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Assessment of Prognosis Post-Myocardial Infarction

Date: May 16, 2012
Result type: Resources

Indication Overview

According to the International Classification of Diseases (ICD), myocardial infarction (MI) — also known as acute myocardial infarction (AMI) or a heart attack, acute coronary syndrome (ACS), angina pectoris, and other forms of coronary heart disease (CHD) are all classified as ischemic heart disease (IHD).1 An AMI occurs when a coronary plaque ruptures, causing a blood clot which may partially or completely block blood flow to the downstream heart muscle.2 Lack of blood flow results in the death of cardiac muscle cells. Blood flow has to be restored promptly to prevent further loss of cardiac muscle cells.

Prognosis following MI depends on a number of factors including geographic location, patient's health, extent of heart damage, and treatment given.3,4 Early risk stratification post-MI is important to determine patients at increased risk for a recurrent ischemic event and those at increased risk for cardiac death (arrhythmic or non-arrhythmic). Imaging allows for in-hospital assessment of prognosis and may guide patient post-MI management. If a patient is at high-risk for another event, treatment planning will likely be more aggressive and include invasive coronary angiography and possibly coronary revascularization.

Population: Patients who have been diagnosed with myocardial infarction.

Intervention: Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) using technetium-99m (99mTc )-labelled radiotracers.

During MPI, the radiopharmaceutical is taken up by the myocardium in proportion to regional blood flow. At rest, regional blood flow is similar in both stenotic and non-stenotic arteries. During stress by either exercise or pharmacological stressors (vasodilators or dobutamine) in the presence of coronary stenosis, the myocardium region supplied by the stenotic artery receives less coronary blood flow, resulting in less uptake of the radiopharmaceutical and an observed perfusion defect. The resulting image using 99mTc-labelled radiotracer SPECT provides information regarding infarct size and residual myocardium at risk, and allows for the calculation of an ejection fraction.5 Infarct size, myocardium at risk, and left ventricular ejection fraction are predictors of mortality.6

Comparators: For this report, the following diagnostic tests are considered as alternatives to 99mTc-labelled radiotracer SPECT:

  • Computed tomography (CT) coronary angiography
  • Stress echocardiogram (Echo)
  • Stress magnetic resonance imaging (MRI)
  • Stress positron emission tomography (PET)
  • Stress 201thallium SPECT (201Tl-SPECT).

Outcomes: Eleven outcomes (referred to as criteria) are considered in this report:

  • Criterion 1: Size of the affected population
  • Criterion 2 : Timeliness and urgency of test results in planning patient management
  • Criterion 3: Impact of not performing a diagnostic imaging test on mortality related to the underlying condition
  • Criterion 4: Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition
  • Criterion 5: Relative impact on health disparities
  • Criterion 6: Relative acceptability of the test to patients
  • Criterion 7: Relative diagnostic accuracy of the test
  • Criterion 8: Relative risks associated with the test
  • Criterion 9: Relative availability of personnel with expertise and experience required for the test
  • Criterion 10: Accessibility of alternative tests (equipment and wait times)
  • Criterion 11: Relative cost of the test.

Definitions of the criteria are in Appendix 1.

Methods

The literature search was performed by an information specialist using a peer-reviewed search strategy.

Published literature was identified by searching the following bibliographic databases: MEDLINE with In-Process records and daily updates via Ovid; The Cochrane Library (2011, Issue 1) via Wiley; and PubMed. The search strategy consisted of both controlled vocabulary, such as the National Library of Medicine's MeSH (Medical Subject Headings), and keywords. The main search concepts were radionuclide imaging and myocardial infarction.

Methodological search filters were applied to limit retrieval to health technology assessments, systematic reviews, meta-analyses, randomized controlled trials, and controlled clinical trials, including diagnostic accuracy studies. Where possible, retrieval was limited to the human population. The literature search was also limited to the English language. No date limits were applied for the systematic review search. The primary studies search was limited to documents published between January 1, 2006 and February 24, 2011. Regular alerts were established to update the search until October 2011. Detailed search strategies are located in Appendix 2.

Grey literature (literature that is not commercially published) was identified by searching relevant sections of the CADTH Grey Matters checklist. Google was used to search for additional web-based materials. The searches were supplemented by reviewing the bibliographies of key papers. See Appendix 2 for more information on the grey literature search strategy.

Targeted searches were done as required for the criteria, using the aforementioned databases and Internet search engines. When no literature was identified addressing specific criteria, experts were consulted.

Search Results

Forty-six potential HTA, SR, and MA articles were identified and 11 were subjected to full text review. There were no MAs of the diagnostic accuracy of 99mTc-labelled radiotracer SPECT head-to-head comparisons with any comparator.

There were 480 primary study articles identified of which 44 were subjected to full-text screening. Two studies identified in the primary literature search evaluated the diagnostic accuracy of 99mTc- labelled radiotracer SPECT versus its comparators in the assessment of prognosis post-MI: one comparing 99mTc-labelled radiotracer SPECT with echo and MRI7 and one comparing 99mTc-labelled radiotracer SPECT with MRI.8 One additional study,9 comparing the diagnostic accuracy of 99mTc-labelled radiotracer SPECT and rubidium-82 (82Rb) PET in a broader patient population, was also included. No studies comparing 99mTc-labelled radiotracer SPECT with CT or 201TI-labelled radiotracer SPECT met the inclusion criteria.

Two guidelines of interest were identified in the grey literature search: the American College of Cardiology (ACC) /American Heart Association (AHA) guidelines for the management of patients with ST-segment elevation myocardial infarction (STEMI)10 and those for patients with non-STEMI (NSTEMI).11

Summary table

Table 1: Summary of Criterion Evidence

Domain 1: Criteria Related to the Underlying Health Condition
Criterion Synthesized Information
1 Size of the affected population There were 60,996 hospitalizations due to heart attacks in the 2006/2007 fiscal year (crude rate: 188.2 per 100,000 people).12 66,707 Canadians were hospitalized for a heart attack in the 2008/2009 fiscal year (age-standardized rate: 217 per 100,000 adults, 20 years of age or older).13 Myocardial infarction (MI) rates vary across the country; however, the rate is lowest in Nunuvat (112/100,000; range: 49 to 176) and highest in Newfoundland and Labrador (347/100,000; range: 330 to 363).13

The size of the affected population is more than 1 in 1,000 (0.1%) and less than or equal to 1 in 100 (1%).
2 Timeliness and urgency of test results in planning patient management A delay in the revascularization process may result in irreversible damage to the myocardium and is associated with an increase in mortality.2 Established nuclear medicine procedure wait times aim to optimize patient care and suggest that MPI should be performed within 24 hours for an emergency case (immediate danger to life, required for therapeutic management) and within three days for urgent cases (situation is unstable and has the potential to deteriorate quickly and result in an emergency admission).14,15 Imaging results have moderate impact on patient management.
3 Impact of not performing a diagnostic imaging test on mortality related to the underlying condition The ACC/AHA guidelines for the management of patients with NSTEMI estimate the annual mortality rate to be between 1% (low risk) and 3% (high risk).11 Improper risk stratification, as a result of not performing a diagnostic imaging test, could result in inappropriate treatment and could increase patient's risk of mortality. Diagnostic imaging test results can have a moderate impact on mortality.
4 Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition Imaging allows for the identification of patients at risk of having a repeat MI and their appropriate treatment planning. Patients receiving treatment may be less likely to have a repeat MI. QoL scores are higher for MI patients if they believe they have control over their illness and treatment.16 Some patients who did not undergo risk assessment may develop symptoms associated with MI including angina and shortness of breath (MIIMAC expert opinion). These symptoms may be associated with some morbidity and lower QoL. Diagnostic imaging test results can have a moderate impact on morbidity and quality of life.

 

Domain 2: Criteria Comparing 99mTc with an Alternative or Comparing Between Clinical Uses
Criterion Synthesized Information
5 Relative impact on health disparities To be scored locally.

There may be a disparity associated with how women are diagnosed, but this may be due in part to the fact that women are slower to present themselves to an emergency room compared to men.17
6 Relative acceptability of the test to patients A 2004 British study compared patient satisfaction and preference toward SPECT versus MRI adenosine stress myocardial perfusion scans and found little difference.18 The only statistically significant finding was that the SPECT scan was preferred in terms of space on the scanner.18 Three participants (9%) stated that they would not have an MRI again, while two patients (6%) said they would not repeat a SPECT.18 The study authors recognized that the relatively small sample size may have affected their ability to demonstrate statistically significant preference for one scan over the other.18 Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

Patients undergoing CTCA may have concerns about radiation exposure and may also feel claustrophobic while in the scanner.

Echo may be preferred by some patients, as there is no radiation exposure with it. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

Because of the closed space of an MRI, patients may experience feelings of claustrophobia, as well as be bothered by the noise. It has been reported that up to 30% of patients experience apprehension and 5% to 10% endure some severe psychological distress, panic, or claustrophobia.19,20 Some patients may have difficulty remaining still during the scan. Patients are not exposed to radiation during an MRI scan, which may be more acceptable to some. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

PET patients may have concerns about radiation exposure and the intravenous injection of a radiopharmaceutical agent. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

SPECT stress MPI with 99mTc-labelled radiotracers:
  • is minimally less acceptable than CTCA
  • is minimally less acceptable than stress Echo
  • has similar acceptability as stress MRI
  • is minimally less acceptable than stress PET
  • has similar acceptability as stress SPECT with 201TI-labelled radiotracers.
7 Relative diagnostic accuracy of the test

Two studies evaluated the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus its comparators in the assessment of prognosis post-MI: one compared 99mTc-labelled radiotracer SPECT with echo and MRI7 and one compared 99mTc-labelled radiotracer SPECT with MRI.8 Given the limited evidence regarding the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus its comparators in the assessment of prognosis post-MI, one study evaluating the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus PET was included.

Diagnostic Accuracy: Assessment of Prognosis Post-MI
Author, Date N Gold Standard Intervention Sensitivity (%) Specificity (%) Accuracy (%)
Lombardo, 20067 14 99mTc-sestamibi SPECT Echo 83 73 77
MRI 65 78 73
Ibrahim, 20068 78 Coronary angiography MRI 97-100 NR NR
99mTc-sestamibi SPECT 79-89 NR NR
Bateman, 20069 224 (112 PET and 112 SPECT) Clinical coronary angiogram reports 82Rb-PET 87 93 89
99mTc-sestamibi SPECT 82 73 79

Echo = echocardiogram; MRI = magnetic resonance imaging; n = size of a sub-sample; PET = positron emission tomography; 82Rb = rubidium-82; SPECT = single-photon emission computed tomography; 99mTc = Technetium-99m.

Based on the available evidence, the diagnostic accuracy of 99mTc-SPECT is:

  • minimally better than stress CTCA
  • similar to stress Echo
  • minimally lower than stress MRI
  • minimally lower than stress PET
  • minimally better than 201TI-SPECT stress imaging.

8

Relative risks associated with the test

Non–radiation-related risks

The main risks of non-invasive preoperative assessment relate to the stress component of the tests. With exercise stress testing, there is a small risk of the patient sustaining an MI if they have significant coronary artery disease.21 With dipyridamole stress testing, there are multiple potential side effects, including headache, exacerbated asthma, and heart attack (risk of this event is low).21 With adenosine stress testing, side effects similar to dipyridamole may be experienced. Symptoms of chest pain or pressure may also occur, but these side effects disappear quickly once the adenosine administration stops.21 With dobutamine stress testing, some patients may experience light-headedness and nausea. There is a theoretical risk of inducing a fast and abnormal cardiac rhythm (i.e., atrial fibrillation, ventricular tachycardia, ventricular fibrillation); however, this is unlikely with the doses of dobutamine used. The overall risk of sustaining a heart attack from a stress test is estimated to be about 2 to 4 in 10,000.21

Apart from risks associated with stress testing, the radiopharmaceuticals used in SPECT imaging may cause reactions in some patients. These reactions are rare and include skin and anaphylactic reactions.22

With CTCA, some patients may experience mild, moderate, or severe side effects from the contrast agent. The frequency of severe, life-threatening reactions with Gd are extremely rare (0.001% to 0.01%) and the frequency of moderate reactions is also rare (0.004% to 0.7%).23

Apart from risks associated with stress testing, there is a low risk of adverse events associated with the contrast used in stress Echo imaging.

Apart from risks associated with stress testing, some patients may experience a reaction to the contrast agent Gd used in MRI. Reactions may include headaches, nausea, and metallic taste. The frequency of severe, life-threatening reactions with Gd are extremely rare (0.001% to 0.01%) and the frequency of moderate reactions is also rare (0.004% to 0.7%)23

Apart from risks associated with stress testing, the Pharmacopeia Committee of the SNM conducted a four-year prospective evaluation of adverse reactions to PET and reported no adverse reactions among the 33,925 scans conducted in 22 participating PET centres in the United States.24 The risks associated with stress testing would apply for cardiac imaging using PET.

Radiation-related Risks

Among the modalities to diagnose ischemia, SPECT MPI, CTCA, and stress PET expose the patient to ionizing radiation. The average effective dose of radiation delivered with each of these procedures can be found in the following table.

Effective Doses of Radiation
Procedure Average Effective Dose (mSv)
99mTc-SPECT MPI 7 to 12.825
201Tl-SPECT MPI 17 to 4125,26
Cardiac 18FDG-PET 7 to 14 (MIIMAC expert opinion)26
Cardiac 82Rb-PET 1.1 to 5.026-28
Cardiac 13NH3-PET 1.5 to 2.228
CTCA 2.1 to 1629,30
MRI 0
Echo 0
Average background dose of radiation per year 1-3.031-33

CTCA = computed tomography coronary angiography; Echo = echocardiogram; 18FDG = fluorodeoxyglucose; MPI = myocardial perfusion imaging; mSv = millisievert; 13NH3 = 13N-labelled ammonia; PET = positron computed tomography; 82Rb = rubidium-82; SPECT = single-photon emission computed tomography; 99mTc = Technetium-99m; 201Tl = thallium-201.

Overall, 99mTc-SPECT MPI:

  • and CTCA have similar safety profiles
  • and stress Echo have similar safety profiles
  • and stress MRI have similar safety profiles
  • and stress PET have similar safety profiles
  • and 201TI-SPECT have similar safety profiles.
9 Relative availability of personnel with expertise and experience required for the test In Canada, physicians involved in the performance, supervision, and interpretation of diagnostic nuclear imaging, CT scans, MRI, and U/S should be diagnostic radiologists or nuclear medical physicians. According to the CMA, there are 1,149 practicing cardiologists in Canada (CMA, 2011). Not all radiologists, nuclear medical physicians, nuclear cardiologists, or cardiologists have the expertise to conduct 99mTc-SPECT and all of its alternatives. For example, a 2002 report by the Canadian Cardiovascular Society reported that 43% of cardiologists do Echo.

Assuming the necessary equipment is available, if 99mTc-SPECT imaging is not available, it is estimated that:
  • 25% to 74% of the procedures can be performed in a timely manner using CTCA
  • 25% to 74% of the procedures can be performed in a timely manner using Echo
  • fewer than 25% of the procedures can be performed in a timely manner using MRI
  • 25% to 74% of the procedures can be performed in a timely manner using PET
  • more than 95% of the procedures can be performed in a timely manner using 201TI-SPECT.
10 Accessibility of alternative tests (equipment and wait times) For SPECT MPI, nuclear medicine facilities with gamma cameras (including SPECT) are required. As of 2007, no nuclear medicine cameras are available in the Yukon, Northwest Territories, or Nunavut.34

No CT scanners are available in Nunavut.35 For CT scanners, the average weekly use ranged from 40 hours in PEI to 69 hours in Ontario, with a national average of 60 hours.34 In 2010, the average wait time for a CT scan in Canada is 4.2 weeks.36 The average wait time for a CTCA was not reported. Of note, not all CT scanners are capable of performing cardiac CT.

No MRI scanners are available in the Yukon, Northwest Territories, or Nunavut.35 According to CIHI's National Survey of Selected Medical Imaging Equipment database, the average number of hours of operation per week for MRI scanners in 2006–2007 ranged from 40 hours in PEI to 99 hours in Ontario, with a national average of 71 hours.34 In 2010, the average wait time for MR imaging in Canada was 9.8 weeks.36

A 2010 Environmental Scan published by CADTH reported that there are approximately 31 Canadian centres equipped to perform PET scans.37 These centres are located in the provinces of British Columbia, Alberta, Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia.37 There are a total of 36 PET or PET/CT scanners in Canada, four of which are used for research purposes only.37

U/S machines are widely available across the country. According to the Fraser Institute, the average wait time for U/S in 2010 was 4.5 weeks.36
  • 25% to 74% of the procedures can be performed in a timely manner using CTCA
  • 75% to 94% of the procedures can be performed in a timely manner using Echo
  • fewer than 25% of the procedures can be performed in a timely manner using MRI
  • fewer than 25% of the procedures can be performed in a timely manner using PET
  • more than 95% of the procedures can be performed in a timely manner using 201TI-SPECT.
11 Relative cost of the test

According to our estimates, the cost of myocardial perfusion imaging with 99mTc-based radioisotopes is $964.53. The cost of myocardial perfusion imaging with 201TI or with PET is assumed to be greater than imaging with 99mTc-based radioisotopes. Stress MRI is minimally less costly than myocardial perfusion imaging with 99mTc. CTCA and stress echo are moderately less costly.

Relative costs
Test Total costs ($) Cost of test relative to 99mTc-based test ($)
99mTc-SPECT MPI 964.53 Reference
201TI-SPECT MPI 964.53 +0.00
CTCA 506.03 -458.50
Stress Echo 466.90 -497.63
Stress MRI 835.16 -129.37
Stress PET 1128.60 +164.07

ACC = American College of Cardiology; AHA = American Heart Association; AMI = acute myocardial infarction; CIHI = Canadian Institute for Health Information; CMA = Canadian Medical Association; CT = computed tomography; CTCA = computed tomography coronary angiography; Echo = stress echocardiography; 18FDG = 18F-fluorodeoxglucose; Gd = gadolinium; MI = myocardial infarction; MPI = myocardial perfusion imaging; MRI = magnetic resonance imaging; mSv = millisievert; NSTEMI = non-ST elevation myocardial infarction; PET = positron emission tomography; Prof = professional; QoL = quality of life; SNM = Society of Nuclear Medicine; SPECT = single-photon emission computed tomography; Tech = technical; 82Rb = rubidium-82; 99mTc = Technetium-99m; 201Tl = thallium-201; U/S = ultrasound.

Criterion 1: Size of affected population (link to definition)

In 2009, the Public Health Agency of Canada (PHAC) published a report on heart disease and stroke in Canada.12 According to this report, there were 60,996 hospitalizations due to heart attacks in the 2006-2007 fiscal year (crude rate: 188.2 per 100,000 people).12 The authors of the report noted that the age-standardized rate of hospitalization due to heart attack has decreased from 1971 to 2007, likely due to better prevention and management of ischemic heart disease.12

A 2010 publication by Statistics Canada and the Canadian Institute for Health Information (CIHI) reported that 66,707 Canadians were hospitalized for a heart attack in the 2008-2009 fiscal year and provided an age-standardized hospitalization rate of 217/100,000 adults (20 years of age or older).13 This report also noted that 2,266 Canadians (3.4% of heart attack victims) had more than one heart attack in a year.13

MI rates vary across the country; however, the rate is lowest in Nunuvat: 112/100,000 (range: 49 to 176) and highest in Newfoundland and Labrador 347/100,000 (range 330 to 363).13

Return to Summary Table.

Criterion 2: Timeliness and urgency of test results in planning patient management (link to definition)

A delay in the revascularization process may result in irreversible damage to the myocardium and is associated with an increase in mortality.2 Established nuclear medicine procedure wait times aim to optimize patient care and suggest that MPI should be performed within 24 hours for an emergency case (immediate danger to life, required for therapeutic management) and within three days for urgent cases (situation is unstable and has the potential to deteriorate quickly and result in an emergency admission).14,15

Return to Summary Table.

Criterion 3: Impact of not performing a diagnostic imaging test on mortality related to the underlying condition (link to definition)

The goals of non-invasive stress testing are to:

  • determine the presence or absence of ischemia
  • estimate patient prognosis.11

Therefore, the impact of not performing a diagnostic imaging test could include misdiagnosis of ischemia or improper risk stratification.

Misdiagnosis of ischemia

A study published in 200038 investigated the incidence misdiagnosis of acute cardiac ischemia (i.e., either acute myocardial infarction or unstable angina) in ten United States hospitals. The hospitals included a mix of public, private, community, and tertiary care hospitals with urban, suburban, and semi-rural catchment areas in the Midwestern, Southeastern, and Northeastern United States.38 The rate of missed diagnoses of MI among non-hospitalized cases was 2.1% (19 of 889).38 Importantly, the risk-adjusted ratio of observed to predicted mortality showed that non-hospitalized patients with an MI had a risk of death that was 1.9 (95% confidence interval [CI], 0.7 to 5.2) times that of the patients who were hospitalized.

Improper risk stratification

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the management of patients with NSTEMI include a table of non-invasive criteria for estimating patient risk of mortality (Appendix 3).11 According to these criteria, the annual mortality rate varies from 1% (low risk) to greater than 3% (high risk).11 Improper risk stratification, as a result of not performing a diagnostic imaging test, could result in improper treatment and could increase a patient's risk of mortality.

Return to Summary Table.

Criterion 4: Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition (link to definition)

A meta-analysis published in 2007 of 17 MPI studies including 8,008 subjects (mean age 54 years) reported the risk of an MI after a normal MPI test was 1.2%.39

The estimated prevalence of the Ontario population in 2004 that survived a previous MI hospital admission is 2.03% (95% CI, 2.01 to 2.05) or approximately 170,000 people.40

There were five studies identified (1999 to 2010)16,41-44 that measured the quality of life (QoL) of patients with an MI using the Medical Outcomes Study Short-Form 36 (SF-36),45 which is a generic QoL instrument. The SF-36 instrument contains eight domains: physical function (PF), role-physical (RP), bodily pain (BP), general health (GH), vitality (VT), social function (SF), role-emotional (RE), mental health (MH); and two summary scores — physical component score (PCS) and mental component score (MCS). Scores are all standardized and range from zero to 100, with higher scores indicating better QoL.

Brown et al.43 sent questionnaires to a cohort of 495 patients from the Nottingham Heart Attack Register who had an MI in 1992 and were still alive four years later. The SF-36 scores were compared with two population norms: Oxford norms for patients under the age of 65 and Sheffield norms for patients over 65. Statistically significantly lower scores for all eight domains were reported by MI survivors less than 65 years of age. There were no differences in the Nottingham patient scores and the Sheffield normative scores for patients greater than 65 years of age, suggesting that QoL scores of patients of retirement age or older are similar to four-year MI survivors. Similar results are reported by a recent 2010 report by Alsén et al.16 who followed 204 Swedish MI patients, except that bodily pain was not different between the MI patients and the normative group.

Brink et al.42 followed a cohort of Swedish MI patients — 33 women (mean age [standard deviation (SD)]: 64.6 years [9.8 years] and 65 men (mean age [SD]: 71.4 years [8.7years]). The authors reported improved SF-36 scores at one year compared to five months post-MI, with the changes reaching statistical significance for the VT, RE, and MH domains, as well as the MCS score. The BP score for the MI group was the only domain score that reached the level of the normative score. In comparison with normative scores, women scored statistically significantly lower on four domains (PF, RP, SF, RE), whereas men reported statistically significantly lower scores on three domains (PF, RP, VT).

Failde and Soto44 measured QoL using the SF-36 at three months post-MI in 76 Spanish patients, of which 78.5% were > 55 years of age. The authors reported statistically significantly lower scores in the PF, GH, VT, and PCS scores. The other domain scores were not different. This is similar to a 2001 Canadian study,41 where 587 patients were enrolled in a QoL-after-MI study. The mean age (SD) of the patients was 61 years (1.2 years). The authors reported that PCS and MCS scores were slightly lower than the baseline scores and they did not change throughout the one-year follow-up.

An inability to return to work or be fit for work, chest pain on a weekly basis, use of inhalers, anxiolytic/hypnotics, and antiarrhythmics were all associated with lower QoL scores.43 The more patients believed their illness to be chronic and episodic in nature, and the more they believed that the condition would have consequences in their lives, the lower the PSC and MCS scores.16 Higher PCS scores were seen when the patients believed they had more personal and treatment control over their illness.16 Age and previous bypass surgery are predictors of impaired PSC scores.41 Having a subsequent MI after discharge is associated with a statistically significantly increased risk for decline in physical functioning (odds ratio [OR]=2.64; 95% CI, 1.45 to 4.82, P < 0.001).46

Return to Summary Table.

Criterion 5: Relative impact on health disparities (link to definition)

In a population-based study of patients hospitalized for an MI from four American centres, published in 2008,47 it was reported that women with no history of MI were less likely to undergo angiography (OR 0.72 [95% CI, 0.57 to 0.89]) or Echo (OR 1.58 [95% CI, 1.32 to 1.90]). In the two sites where there was a large number of patients of black race, they reported that black people were more likely to undergo an Echo (OR 1.89 [CI, 1.62 to 2.19]) or have nuclear testing (OR 1.63 [95% CI, 1.27 to 2.09]) compared to Caucasian patients.

From a German registry, female patients with an acute ST-elevation MI had a pre-hospital delay of 195 minutes, and fewer women presented to the emergency room during the first hour following the onset of symptoms.17

Return to Summary Table.

Criterion 6: Relative acceptability of the test to patients (link to definition)

SPECT
A 2004 British study compared patient satisfaction and preference toward SPECT versus MRI adenosine stress myocardial perfusion scans and found little difference.18 Forty-one patients who had undergone both SPECT and MRI were sent a retrospective questionnaire within two weeks of scan completion. Thirty-five completed questionnaires were returned. When asked, "If the two tests (nuclear heart scan and MRI) could provide the same information, which of the two would you prefer?", 12 patients (34%) stated a preference for MRI, nine (26%) stated a preference for SPECT, and 14 (40%) stated no preference.18 Patients rated the two tests similarly on overall preference, duration, comfort, and safety, with a non-significant preference for MRI on all of the above mentioned.18 The only statistically significant finding was that the SPECT scan was preferred in terms of space on the scanner.18 Three participants (9%) stated that they would not have an MRI again, while two patients (6%) said they would not repeat a SPECT.18 Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients. The study authors recognized that the relatively small sample size may have affected their ability to demonstrate statistically significant preference for one scan over the other.18

CTCA
Patients undergoing computed tomography coronary angiography scans may have concerns about radiation exposure and may also feel claustrophobic while in the scanner. This is less of a problem with new CT scanners (MIIMAC expert opinion).

Stress Echo
This test is likely to be well-tolerated by patients. Echo may be preferred by some patients, as there is no radiation exposure. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

Stress MRI
Because of the closed space of an MRI, patients may experience feelings of claustrophobia, as well as being bothered by the noise This may be less of a problem with new MRI machines, if available (MIIMAC expert opinion). It has been reported that up to 30% of patients experience apprehension, and 5% to 10% endure some severe psychological distress, panic, or claustrophobia.19,20 Some patients may have difficulty remaining still during the scan. Patients are not exposed to radiation during an MRI scan, which may be more acceptable to some. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

Stress PET MPI (82Rb or 13N-labelled ammonia [13NH3])
Patients may have concerns about radiation exposure and the intravenous injection of a radiopharmaceutical agent. Exercise or pharmacological agents used to induce stress conditions may be unpleasant for some patients.

Return to Summary Table.

Criterion 7: Relative diagnostic accuracy of the test (link to definition)

Two studies identified in the primary literature search evaluated the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus its comparators in the assessment of prognosis post-MI: one comparing 99mTc-labelled radiotracer SPECT with Echo and MRI7 and one comparing 99mTc-labelled radiotracer SPECT with MRI.8 No studies comparing 99mTc-labelled radiotracer SPECT with CT, PET, or 201TI-labelled radiotracer SPECT met the inclusion criteria.

MRI and myocardial contrast echo (MCE) versus 99mTc-labelled radiotracer SPECT
Lombardo et al.7 evaluated the accuracy of MCE and MRI in identifying myocardial perfusion defects in AMI patients, using 99mTc-labelled radiotracer SPECT as the reference standard. The study population consisted of 14 patients admitted with a diagnosis of first acute MI.7 MCE, MRI, and 99mTc-labelled radiotracer SPECT studies were performed within five days of hospital admission, while standard coronary angiography was conducted within the initial seven days.7 Five patients underwent percutaneous coronary intervention (PCI) and five were treated with thrombolytic therapy.7 Only 153 of 224 segments (68%) imaged with Echo and 220 of 224 segments (98%) imaged by MRI were suitable for interpretation and analysis. Echo showed a statistically significantly higher sensitivity than MRI, when compared with 99mTc-labelled radiotracer SPECT (Table 2).

Table 2: Diagnostic Accuracy of Echo and MRI with 99mTc-labelled Radiotracer SPECT as the Reference Standard

Criterion Echo MRI
Sensitivity (%) 83 65
Specificity (%) 73 78
Accuracy (%) 77 73

Echo = echocardiography; MRI = magnetic resonance imaging SPECT = single-photon emission computer tomography; 99mTc = Technetium-99m.
MRI versus 99mTc-labelled radiotracer SPECT

Ibrahim et al.8 investigated the diagnostic value of contrast-enhanced MRI and 99mTc-labelled radiotracer SPECT for the detection of myocardial necrosis in patients early on following an AMI and reperfusion therapy. Seventy-eight patients with a diagnosis of AMI (based on chest pain lasting a minimum of 20 minutes and associated with electrocardiographic changes and elevated troponin T activity) were included in the analysis. MRI and 99mTc-labelled radiotracer SPECT tests were performed in all patients a median of seven days post-MI.8 MRI and 99mTc-labelled radiotracer SPECT images were analyzed using a 17-segment model, with semi-quantitative scoring. Sensitivity of MRI and SPECT was determined for the detection of myocardial necrosis. The sensitivity of MRI was shown to be higher in all vascular areas, although the difference was not statistically significant (Table 3).8

Table 3: Sensitivity of MRI and 99mTc-labelled Radiotracer SPECT for Detection of Myocardial Necrosis8

Infarct-Related Artery 99mTc-labelled Radiotracer SPECT MRI
Left anterior descending artery (%) 89 97
Left circumflex artery (%) 79 100
Right coronary artery (%) 87 97

MRI = magnetic resonance imaging; SPECT = single-photon emission computed tomography; 99mTc = technetium-99.

Given the limited evidence regarding the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus its comparators in the assessment of prognosis post-MI, studies evaluating the diagnostic accuracy of 99mTc-labelled radiotracer SPECT versus its comparators in the diagnosis of ischemia are subsequently included.

82Rb-PET versus 99mTc-labelled radiotracer SPECT

Bateman et al.9 compared the diagnostic accuracy of 99mTc-sestamibi SPECT and 82Rb-PET for MPI of patients matched by gender, body mass index, and presence and extent of coronary disease. Included patients were identified retrospectively from an electronic nuclear cardiology database and were categorized as having a low likelihood for coronary artery disease (n = 54) or had coronary angiography within 60 days (n = 170).9 Twenty-four of the 112 patients (21%) who underwent SPECT and 28 of the 112 patients (25%) who underwent PET had had a previous MI.9 Four experienced nuclear medicine cardiologists blinded to patients' clinical information interpreted scans obtained from 112 99mTc-labelled radiotracer SPECT and 112 82Rb-PET electrocardiogram-gated rest/pharmacologic stress studies.9 By consensus, the quality of the perfusion images were deemed superior with PET (78% and 79% for rest and stress scans, respectively) than SPECT (62% and 62%; both P > 0.05).9 Interpretive certainty was also rated higher with PET versus SPECT scans (96% versus 81%, P = 0.001). Diagnostic accuracy was better for PET over SPECT. For patients with a stenosis severity of 70% by angiography, the sensitivity was 82% for SPECT and 87% for PET (P = 0.41), and the specificity was 73% for SPECT versus 93% for PET (P = 0.02), resulting in a significant improvement in overall accuracy by PET (89% versus 79%, P = 0.03) (Table 4).9 Bateman and colleagues conclude that, for this patient population, a major benefit of PET versus SPECT is higher diagnostic accuracy.9

Table 4: Diagnostic Characteristics of 18FDG-PET and 99mTc-labelled Radiotracer SPECT (70% stenosis as CAD)

  99mTc-labelled radiotracer SPECT 82RB-PET
Sensitivity (%) 82 87
Specificity (%) 73 93
Accuracy (%) 79 89

CAD = coronary artery disease; 18FDG-PET = fluorodeoxyglucose -18 positron emission tomography; 82RB-PET = rubidium-82 positron emission tomography; SPECT = single-photon emission computer tomography; 99mTc = technetium-99.

Return to Summary Table.

Criterion 8: Relative risks associated with the test (link to definition)

Non–radiation-related risks

Cardiac stress tests
The main risks of non-invasive preoperative assessment relate to the stress component of the tests:

  • With exercise stress testing, there is a small risk of the patient sustaining an MI if they have significant coronary artery disease.21
  • With dipyridamole stress testing, there are multiple potential side effects, including headache, exacerbated asthma, and heart attack (risk of this event is low).21
  • With adenosine stress testing, side effects similar to dipyridamole may be experienced. Symptoms of chest pain or pressure may also occur, but these side effects go away quickly once the adenosine administration stops.21
  • With dobutamine stress testing, some patients may experience light-headedness and nausea. There is a theoretical risk of inducing a fast and abnormal cardiac rhythm (i.e., atrial fibrillation, ventricular tachycardia, ventricular fibrillation); however, this is unlikely with the doses of dobutamine used. A slight risk of MI exists.21

The overall risk of sustaining a heart attack from a stress test is estimated to be about two to four per 10,000 tests.21

Stress SPECT
Apart from risks associated with stress testing, a review of undesirable events with radiopharmaceuticals reported anaphylactic reactions and erythema multiforme (i.e., a type of skin reaction) with sestamibi, although these reactions may be rare.22

CTCA
Some patients may experience an allergic reaction to the contrast agent (if required), which may worsen with repeated exposure.48 In addition, patients may experience mild side effects from the contrast agent such as nausea, vomiting, or hives. A 2009 retrospective review of all intravascular doses of low-osmolar iodinated and gadolinium (Gd) contrast materials administered at the Mayo Clinic between 2002 and 2006 (456,930 doses) found 0.15% of patients given CT contrast material experienced side effects, most of which were mild. A serious side effect was experienced by 0.005% of patients.49 CT is contraindicated in patients with elevated heart rate, hypercalcemia, and impaired renal function. Patients must be able to take rate-lowering medications. Although rarely used in cardiac imaging, Gd is contraindicated in patients with renal failure or end-stage renal disease, as these patients are at risk of nephrogenic systemic fibrosis. According to the American College of Radiology Manual on Contrast Media,23 the frequency of severe, life-threatening reactions with Gd are extremely rare (0.001% to 0.01%). Moderate reactions resembling an allergic response (i.e., rash, hives, urticaria) are also very unusual and range in frequency from 0.004% to 0.7%.23

Stress Echo
Apart from risks associated with stress testing, three relatively large studies with sample sizes of 42,408 patients (2009),50 26,774 patients (2009),51 and 5,069 patients (2008)52 compared cardiac outcomes (non-fatal MI or death) between patients who underwent contrast-enhanced Echo with patients who had an Echo without contrast. All three studies concluded that the risk of an adverse event is low and is no different than that of patients who received no contrast. No additional risks associated with Echo were identified.

Stress MRI
Apart from risks associated with stress testing, MRI is contraindicated in patients with metallic implants including pacemakers.53 MRI is often used in conjunction with the contrast agent Gd. Some patients may experience an allergic reaction to the contrast agent (if required), which may worsen with repeated exposure.48 Side effects of Gd include headaches, nausea, and metallic taste. Gd is contraindicated in patients with renal failure or end-stage renal disease, as they are at risk of nephrogenic systemic fibrosis. According to the American College of Radiology Manual on Contrast Media,23 the frequency of severe, life-threatening reactions with Gd are extremely rare (0.001% to 0.01%). Moderate reactions resembling an allergic response (i.e., rash, hives, urticaria) are also very unusual and range in frequency from 0.004% to 0.7%.23

Stress PET
The Pharmacopeia Committee of the Society of Nuclear Medicine conducted a four-year prospective evaluation of adverse reactions to PET and reported no adverse reactions among the 33,925 scans conducted in 22 participating PET centres in the United States.24 The risks associated with stress testing would apply for cardiac imaging using PET.

Radiation-related Risks

Among the modalities to diagnose ischemia, SPECT MPI, CTCA, and stress PET expose the patient to ionizing radiation. The average effective dose of radiation delivered with each of these procedures can be found in Table 5.

Table 5: Effective Doses of Radiation

Procedure Average Effective Dose (mSv)
99mTc-SPECT MPI 7 to 12.825
201Tl-SPECT MPI 17 to 4125,26
Cardiac 18FDG-PET 7 to 14 (MIIMAC expert opinion)26
Cardiac 82Rb-PET 1.1 to 5.026-28
Cardiac 13NH3-PET 1.5 to 2.228
CTCA 2.1 to 1629,30
MRI 0
Echo 0
Average background dose of radiation per year 1-3.031-33

CTCA = computed tomography coronary angiography; Echo = echocardiography; 18FDG = fluorodeoxyglucose -18; MPI = myocardial perfusion imaging; MRI = magnetic resonance imaging; mSv = millisevert; 13NH3 = 13N-labelled ammonia; PET = positron emission tomography; 82Rb = rubidium-82; SPECT = single-photon emission tomography; 99mTc = technetium-99; 201Tl = thallium-201.

Return to Summary Table.

Criterion 9: Relative availability of personnel with expertise and experience required for the test (link to definition)

The personnel required for the performance of the imaging tests to assess patient prognosis post-MI are presented by imaging modality. A summary of the availability of personnel required for the conduct of post-myocardial infarction assessment of prognosis, by SPECT or any of the alternative imaging modalities, is provided in Table 6.

99mTc-labelled radiotracer SPECT MPI
In Canada, physicians involved in the performance, supervision, and interpretation of cardiac nuclear imaging (specifically MPI using 99mTc-labelled radiotracer) should be nuclear medicine physicians with particular expertise in nuclear cardiology (nuclear cardiologists). Cardiologists also provide nuclear cardiology services. According to the Canadian Medical Association (CMA), there are 1,149 practicing cardiologists in Canada (CMA, 2011).

Nuclear medicine technologists are required to conduct MPI. Technologists must be certified by the Canadian Association of Medical Radiation Technologists (CAMRT) or an equivalent. A stress technologist or dedicated physician should be on hand to monitor any procedures involving stress testing.

All alternative imaging modalities
In Canada, physicians involved in the performance, supervision, and interpretation of diagnostic CT scans, MRI, and ultrasound (U/S) should be diagnostic radiologists34 and must have a Fellowship or Certification in Diagnostic Radiology with the Royal College of Physicians and Surgeons of Canada and/or the Collège des médecins du Québec. Foreign-trained radiologists are also qualified if they are certified by a recognized certifying body and hold a valid provincial license.54 According to the CMA, there are 1,149 practicing cardiologists in Canada (CMA, 2011).

Medical radiation technologists (MRTs) must be certified by CAMRT, or an equivalent licensing body. A stress technologist or dedicated physician should be on hand to monitor any procedures involving stress testing.

Service engineers are needed at regularly scheduled intervals for system installation, calibration, and preventive maintenance of the imaging equipment. The service engineer's qualification will be ensured by the corporation responsible for service and the manufacturer of the equipment used at the site.

Qualified medical physicists (onsite or contracted part-time) should be available for the installation, testing, and ongoing quality control of CT scanners, MR scanners, and nuclear medicine equipment.54

CTCA
CTCA is a CT-based test. Cardiologists provide much of the CTCA service. According to the CMA, there are 1,149 practicing cardiologists in Canada (CMA, 2011).

For the performance of a CT scan, medical radiation technologists certified by CAMRT, or an equivalent licensing body recognized by CAMRT, are required. The training of technologists specifically engaged in CT should meet with the applicable and valid national and provincial specialty qualifications.

Stress Echo
Echocardiography is a U/S-based test. Cardiologists provide much of the Echo service. A 2002 report by the Canadian Cardiovascular Society (CCS) reported that 43% of cardiologists do echocardiography. According to the CMA, there are 1,149 practicing cardiologists in Canada (CMA, 2011). It is assumed that less than 500 of them do echocardiography.

Sonographers (or ultrasonographers) should be graduates of an accredited school of sonography or have obtained certification by the Canadian Association of Registered Diagnostic Ultrasound Professionals (CARDUP). They should be members of their national or provincial professional organizations. Sonography specialties include general sonography, vascular sonography, and cardiac sonography.34 In Quebec, sonographers and MRTs are grouped together; in the rest of Canada, sonographers are considered a distinct professional group.34 A stress technologist or dedicated physician should be on hand to monitor any procedures involving stress testing.

Stress MRI
Medical technologists must have CAMRT certification in MRI or be certified by an equivalent licensing body recognized by CAMRT. A stress technologist or dedicated physician should be on hand to monitor any procedures involving stress testing.

Stress PET
In Canada, physicians involved in stress PET scanning should be nuclear medicine physicians, nuclear cardiologists, or cardiologists with training and expertise in nuclear imaging. In Canada, physicians who perform PET imaging studies must be certified by either the Royal College of Physicians and Surgeons of Canada or le Collège des médecins du Quebec.

Technologists must be certified by CAMRT or an equivalent licensing body. A stress technologist or dedicated physician should be on hand to monitor any procedures involving stress testing.

Table 6: Medical Imaging Professionals in Canada, 200634

Jurisdiction Diagnostic Radiology Physicians Nuclear Medicine Physicians MRTs Nuclear Medicine Technologists Sonographers Medical Physicists
NL 46 3 263 15 NR NR
NS 71 5 403 71 NR NR
NB 47 3 387 55 NR NR
PEI 7 0 57 3 NR 0
QC 522 90 3,342 460 NR NR
ON 754 69 4,336 693 NR NR
MB 58 8 501 42 NR NR
SK 61 4 359 36 NR NR
AB 227 18 1,229 193 NR NR
BC 241 21 1,352 212 NR NR
YT 0 0 0 0 NR 0
NT 0 0 26 1 NR 0
NU 0 0 0 0 NR 0
Total 2,034 221 12,255 1,781 2,900* 322*

AB = Alberta; BC = British Columbia; MB = Manitoba; MRT = medical radiation technologist; NB = New Brunswick; NL = Newfoundland and Labrador; NR = not reported by jurisdiction; NS = Nova Scotia; NT= Northwest Territories; NU = Nunavut; ON = Ontario; PEI= Prince Edward Island; QC = Quebec; YT = Yukon.
* This represents a total for all of the jurisdictions.

Expertise

Two studies determined the intra- and inter-observer variability of 99mTc-labelled radiotracer SPECT, Echo, and MRI images. An Italian study55 evaluated scans from 56 patients (mean age [SD]: 52 years [9 years]) who had an MI and the second study56 evaluated 42 patient scans (mean age [SD]: 59 years [19 years]). The kappa scores for inter- and intra-rater agreement are listed in Table 7.

Table 7: Kappa Scores

Study   99mTc-labelled Radiotracer SPECT Echo MRI
Ferro55 Inter-rater

Intra-rater
0.92

0.96
0.56

0.81
NA

NA
Janardhanan56 Inter-rater

Intra-rater
NA

NA
0.76

0.77
0.66

0.72

Echo = echocardiography; MRI = magnetic resonance imaging; NA=not applicable; SPECT = single-photon emission computed tomography; 99mTc = technetium-99.

Based on the data provided in Table 7, 99mTc-labelled radiotracer SPECT has a better interpretive reproducibility than Echo or MRI.

Others have reported intra-observer variability between two experienced readers evaluating contrast-enhanced Echo images of 4 ± 2% and 1 ± 1% for MRI. The inter-observer variability (images read 15 days later) was reported as 8 ± 3% for contrast-enhanced Echo and 3 ± 1% for MRI .7

Cardiac measures using Echo scans are the least reproducible compared with SPECT and MRI scans.

A report from the United States57 states that employment of cardiovascular technologists and technicians is expected to increase 24% through the year 2018 — much faster than the average for other occupations. Demand will stem from the prevalence of heart disease and the aging population, because older people have a higher incidence of heart disease and other complications of the heart and vascular system.

Return to Summary Table.

Criterion 10: Accessibility of alternative tests (equipment and wait times) (link to definition)

There are notable variations in the availability of medical imaging technologies across Canada. Table 8 provides an overview of the availability of equipment required to detect ischemia. Data for nuclear medicine cameras (including SPECT) are current to January 1, 2007. The number of CT, MRI, and SPECT/CT scanners is current to January 1, 2010. Information on the availability of PET and PET/CT scanners is current to November 30, 2010. Data were not available for Echo.

Table 8: Diagnostic Imaging Equipment in Canada34,35,37

  Nuclear Medicine Cameras CT Scanners MRI Scanners PET or PET/CT
Number of devices 60334 46035 21835 3637
Average number of hours of operation per week (2006-2007) 40 60 71 NA
Provinces and Territories with no devices available YT, NT, NU NU YT, NT, NU NL, PEI, SK, YT, NT, NU

CT = computed tomography; PET = positron emission tomography; MRI = magnetic resonance imaging; NB = New Brunswick; NL. = Newfoundland; NS = Nova Scotia; NU = Nunavut; NT = Northwest Territories; PEI = Prince Edward Island; SK = Saskatchewan; YT = Yukon.

99mTc-labelled radiotracer SPECT
Nuclear medicine facilities with gamma cameras are required for SPECT imaging. Three jurisdictions — the Yukon, the Northwest Territories, and Nunavut — do not have any nuclear medicine equipment.34

CT
No CT scanners are available in Nunavut.35 The average weekly use of CT scanners ranged from 40 hours in PEI to 69 hours in Ontario, with a national average of 60 hours.34 In 2010, the average wait time for a CT scan in Canada is 4.2 weeks.36 The average wait time for CTCA was not reported.

Echo
No information was found to identify how many Echo machines are available in Canada.

MRI
No MRI scanners are available in the Yukon, Northwest Territories, or Nunavut.35 According to the Canadian Institute for Health Information's National Survey of Selected Medical Imaging Equipment database, the average number of hours of operation per week for MRI scanners in 2006–2007 ranged from 40 hours in PEI to 99 hours in Ontario, with a national average of 71 hours.34 In 2010, the average wait time for MRI in Canada was 9.8 weeks.36

PET
A 2010 Environmental Scan published by CADTH reported that there are approximately 31 Canadian centres equipped to perform PET scans.37 These centres are located in the provinces of British Columbia, Alberta, Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia.37 There are 36 PET or PET/CT scanners in Canada, four of which are used for research purposes only.37

Wait times
Wait time benchmarks for cardiac nuclear imaging set by the Wait Time Alliance14 are immediate to 24 hours for emergency cases (immediate danger to life, limb, or organ); within three days for urgent cases (situation that is unstable and has the potential to deteriorate quickly and result in an emergency admission); and within 14 days for scheduled cases (situation involving minimal pain, dysfunction, or disability — routine or elective).

Return to Summary Table.

Criterion 11: Relative cost of the test (link to definition)

Fee codes from the Ontario Schedule of Benefits were used to estimate the relative costs of SPECT MPI and its alternatives. Technical fees are intended to cover costs incurred by the hospital (i.e., radiopharmaceutical costs, medical/surgical supplies, and non-physician salaries). Maintenance fees are not billed to OHIP; estimates here were provided by St. Michael's Hospital in Toronto. Certain procedures (i.e., PET scan, CT scan, MRI scan) are paid for, in part, out of the hospital's global budget; these estimates were provided by The Ottawa Hospital. It is understood that the relative costs of imaging will vary from one institution to the next.

According to our estimates (Table 9), the cost of myocardial perfusion imaging with 99mTc-based radioisotopes is $964.53. The cost of myocardial perfusion imaging with 201TI or with PET is assumed to be greater than imaging with 99mTc-based radioisotopes. Stress MRI is minimally less costly than myocardial perfusion imaging with 99mTc. CTCA and stress echo are moderately less costly.

Table 9: Cost Estimates Based on the Ontario Schedule of Benefits for Physician Services Under the Health Insurance Act (September 2011)58

Fee Code Description Tech. Fees ($) Prof. Fees ($) Total Costs ($)
99mTc-SPECT MPI
J866 Myocardial perfusion scintigraphy application of SPECT (maximum 1 per examination) 44.60 31.10 75.7
J813 Studies with ejection fraction 138.60 82.25 220.85
J807 Myocardial perfusion scintigraphy — resting, immediate post-stress 223.15 50.15 273.3
J808 Myocardial perfusion imaging — delayed 82.15 27.45 109.6
G315/G319 Maximal stress ECG 44.60 62.65 107.25
G111/G112 Dipyridamole Thallium stress test 52.05 75.00 127.05
Maintenance fees — from global budget 50.78   50.78
TOTAL 635.93 328.6 964.53
201TI-SPECT MPI
J866 Myocardial perfusion scintigraphy application of SPECT (maximum 1 per examination) 44.60 31.10 75.7
J813 Studies with ejection fraction 138.60 82.25 220.85
J807 Myocardial perfusion scintigraphy — resting, immediate post stress 223.15 50.15 273.3
J808 Myocardial perfusion imaging — delayed 82.15 27.45 109.6
G315/G319 Maximal stress ECG 44.60 62.65 107.25
G111/G112 Dipyridamole Thallium stress test 52.05 75.00 127.05
Maintenance fees — from global budget 50.78   50.78
TOTAL 635.93 328.6 964.53
CTCA
X235 Cardiothoracic CT   155.25 155.25
Technical cost — from global budget 300.00   300.00
Maintenance fees — from global budget 50.78   50.78
TOTAL 350.78 155.25 506.03
Stress echo
G570/G571 Complete study — 1 and 2 dimensions 76.45 74.10 150.55
G577/G578 Cardiac Doppler study, with or without colour Doppler, in conjunction with complete 1 and 2 dimension echocardiography studies 45.15 36.90 82.05
G315/G319 Maximal stress ECG 44.60 62.65 107.25
G111/G112 Dipyridamole Thallium stress test 52.05 75.00 127.05
TOTAL 218.25 248.65 466.90
Stress MRI
X441C MRI — thorax — multislice sequence   77.20 77.20
X445C (×3) Repeat (another plane, different pulse sequence — to a maximum of 3 repeats)   38.65 (×3) = 115.95 115.95
X499C 3-Dimensional MRI acquisition sequence, including post-processing (minimum of 60 slices; maximum 1 per patient per day)   65.40 65.40
G315/G319 Maximal stress ECG 44.60 62.65 107.25
X486C When cardiac gating is performed (must include application of chest electrodes and ECG interpretation), add 30%   96.36 96.36
Technical cost — from global budget 300.00   300.00
Maintenance fees — from global budget 73.00   73.00
TOTAL 417.60 417.56 835.16
Stress PET
J866 Myocardial perfusion scintigraphy application of SPECT (maximum 1 per examination)   31.10 31.10
J813 Studies with ejection fraction   82.25 82.25
J807 Myocardial perfusion scintigraphy — resting, immediate post-stress   50.15 50.15
J808 Myocardial perfusion imaging — delayed   27.45 27.45
G315/G319 Maximal stress ECG   62.65 62.65
G111/G112 Dipyridamole Thallium stress test   75.00 75.00
Technical cost — from global budget 800.00   800.00
TOTAL 800.00 328.60 1128.60

3-D = three-dimensional; CT = computed tomography; CTCA = computed tomography coronary angiography; ECG = electrocardiogram; MPI = myocardial perfusion imaging; MRI = magnetic resonance imaging; PET = positron emission tomography; Prof. = professional; SPECT = single-photon emission computed tomography; 99mTc = technetium-99m; 201TI = thallium-201; tech. = technical.

Return to Summary Table.

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  56. Janardhanan R, Moon JC, Pennell DJ, Senior R. Myocardial contrast echocardiography accurately reflects transmurality of myocardial necrosis and predicts contractile reserve after acute myocardial infarction. Am Heart J. 2005 Feb;149(2):355-62.
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  58. Ontario Ministry of Health and Long-Term Care. Schedule of benefits for physician services under the Health Insurance Act: effective September 1, 2011 [Internet]. Toronto: OMHLTC; 2011. [cited 2011 Oct 5]. Available from: http://www.health.gov.on.ca/english/providers/program/ohip/sob/physserv/physserv_mn.html

 

Appendix 1: Multi-Criteria Decision Analysis Definitions

Domain 1: Criteria Related to the Underlying Health Condition
Criterion Definition
1. Size of the affected population The estimated size of the patient population that is affected by the underlying health condition and that may potentially undergo the test. The ideal measure is point prevalence, or information on how rare or common the health condition is.
2. Timeliness and urgency of test results in planning patient management The timeliness and urgency of obtaining the test results in terms of their impact on the management of the condition and the effective use of health care resources.
3. Impact of not performing a diagnostic imaging test on mortality related to the underlying condition Impact of not performing the test, in whatever way, on the expected mortality of the underlying condition. Measures could include survival curves showing survival over time, and/or survival at specific time intervals with and without the test.
4. Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition Impact of not performing the test, in whatever way, on the expected morbidity or on the quality of life reduction of the underlying condition. Measures of impact may include natural morbidity outcome measures such as events or disease severity, or might be expressed using generic or disease-specific quality of life rating scales with and without the test.
Domain 2: Criteria Comparing 99mTc with an Alternative, or Comparing between Clinical Uses
Criterion Definition
5. Relative impact on health disparities Health disparities are defined as situations where there is a disproportionate burden (e.g., incidence, prevalence, morbidity, or mortality) amongst particular population groups (e.g., gender, age, ethnicity, geography, disability, sexual orientation, socioeconomic status, and special health care needs).

Impact on health disparities is assessed by estimating the proportion of current clients of the 99mTc-based test that are in population groups with disproportionate burdens.

(Explanatory note: The implication of this definition is that, everything else being the same, it is preferable to prioritize those clinical uses that have the greatest proportion of clients in groups with disproportionate burdens.)
6. Relative acceptability of the test to patients Acceptability of the 99mTc-based test from the patient's perspective compared with alternatives. Patient acceptability considerations include discomfort associated with the administration of the test, out-of-pocket expenses or travel costs, factors that may cause great inconvenience to patients, as well as other burdens. This criterion does not include risks of adverse events but is about everything related to the experience of undergoing the test.
7. Relative diagnostic accuracy of the test Ability of the test to correctly diagnose the patients who have the condition (sensitivity) and patients who do not have the condition (specificity) compared with alternatives.
8. Relative risks associated with the test Risks associated with the test (e.g., radiation exposure, side effects, adverse events) compared with alternatives. Risks could include immediate safety concerns from a specific test or long-term cumulative safety concerns from repeat testing or exposure.
9. Relative availability of personnel with expertise and experience required for the test Availability of personnel with the appropriate expertise and experience required to proficiently conduct the test and/or interpret the test findings compared with alternatives.
10. Accessibility of alternatives (equipment and wait times) Availability (supply) of equipment and wait times for alternative tests within the geographic area. Includes consideration of the capacity of the system to accommodate increased demand for the alternatives. Excludes any limitation on accessibility related to human resources considerations.
11. Relative cost of the test Operating cost of test (e.g., consumables, heath care professional reimbursement) compared with alternatives.

99mTc = technetium-99m.

 

Appendix 2: Literature Search Strategy

OVERVIEW
Interface: Ovid
Databases: Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R) <1946 to February 24, 2011>
Date of Search: February 24, 2011
Alerts: Monthly search updates began February 24, 2011 and ran until October 2011.
Study Types: Health technology assessments; systematic reviews; meta-analyses; randomized controlled trials; controlled clinical trials; diagnostic accuracy studies
Limits: English language

Publication years 2006-February 2011 for primary studies search; no date limits for systematic review search.

Primary studies search limited to human population
SYNTAX GUIDE
/ At the end of a phrase, searches the phrase as a subject heading
MeSH Medical Subject Heading
.fs Floating subheading
exp Explode a subject heading
* Before a word, indicates that the marked subject heading is a primary topic; or, after a word, a truncation symbol (wildcard) to retrieve plurals or varying endings
ADJ Requires words are adjacent to each other (in any order)
ADJ# Adjacency within # number of words (in any order)
.ti Title
.ab Abstract
.hw Heading word: usually includes subject headings and controlled vocabulary
.tw Text word: searches title, abstract, captions, and full text
.mp Keyword search; includes title, abstract, name of substance word, subject heading word, and other text fields
.pt Publication type
.nm Name of substance word: used to search portions of chemical names and includes words from the CAS Registry/EC Number/Name (RN) fields
.jw Journal words: searches words from journal names
/du Diagnostic use

 

Multi-database Strategy
# Searches
1 exp Myocardial Infarction/
2 ((myocardial or postmyocardial or myocardium or heart or cardiac) adj (infarction or infarctions or infarct or infarcts or infarcted or attack or attacks)).ti,ab.
3 1 or 2
4 Technetium/
5 exp Technetium Compounds/
6 exp Organotechnetium Compounds/
7 exp Radiopharmaceuticals/
8 (Technetium* or Tc-99 or Tc99 or Tc-99m or Tc99m or 99mTc or 99m-Tc).tw,nm.
9 Radionuclide Imaging/ or Perfusion Imaging/
10 radionuclide imaging.fs.
11 radioisotope*.mp.
12 ((radionucl* or nuclear or radiotracer*) adj2 (imag* or scan* or test* or diagnos*)).ti,ab.
13 Exp Tomography, Emission-Computed, Single-Photon/
14 (single-photon adj2 emission*).ti,ab.
15 (SPECT or scintigraph* or scintigram* or scintiphotograph*).ti,ab.
16 Myocardial Perfusion Imaging/
17 (myocardial perfusion imag* or MPI or rMPI or rest-stress test* or cardiac-stress test*).ti,ab.
18 (sestamibi or Hexamibi or Tc MIBI or Cardiolite* or tetrofosmin* or myoview*).ti,ab.
19 (109581-73-9 or 112144-90-8 or 113720-90-4).rn.
20 or/4-19
21 meta-analysis.pt.
22 meta-analysis/ or systematic review/ or meta-analysis as topic/ or exp technology assessment, biomedical/
23 ((systematic* adj3 (review* or overview*)) or (methodologic* adj3 (review* or overview*))).ti,ab.
24 ((quantitative adj3 (review* or overview* or synthes*)) or (research adj3 (integrati* or overview*))).ti,ab.
25 ((integrative adj3 (review* or overview*)) or (collaborative adj3 (review* or overview*)) or (pool* adj3 analy*)).ti,ab.
26 (data synthes* or data extraction* or data abstraction*).ti,ab.
27 (handsearch* or hand search*).ti,ab.
28 (mantel haenszel or peto or der simonian or dersimonian or fixed effect* or latin square*).ti,ab.
29 (met analy* or metanaly* or health technology assessment* or HTA or HTAs).ti,ab.
30 (meta regression* or metaregression* or mega regression*).ti,ab.
31 (meta-analy* or metaanaly* or systematic review* or biomedical technology assessment* or bio-medical technology assessment*).mp,hw.
32 (medline or Cochrane or pubmed or medlars).ti,ab,hw.
33 (cochrane or health technology assessment or evidence report).jw.
34 or/21-33
35 exp "Sensitivity and Specificity"/
36 False Positive Reactions/
37 False Negative Reactions/
38 sensitivit*.ti.
39 (distinguish* or differentiat* or enhancement or identif* or detect* or diagnos* or accura* or comparison*).ti.
40 (predictive adj4 value*).ti,ab.
41 Validation Studies.pt.
42 or/35-41
43 (Randomized Controlled Trial or Controlled Clinical Trial).pt.
44 Randomized Controlled Trial/
45 Randomized Controlled Trials as Topic/
46 Controlled Clinical Trial/
47 Controlled Clinical Trials as Topic/
48 Randomization/
49 Random Allocation/
50 Double-Blind Method/
51 Double-Blind Studies/
52 Single-Blind Method/
53 Single-Blind Studies/
54 Placebos/
55 Control Groups/
56 Control Group/
57 (random* or sham or placebo*).ti,ab,hw.
58 ((singl* or doubl*) adj (blind* or dumm* or mask*)).ti,ab,hw.
59 ((tripl* or trebl*) adj (blind* or dumm* or mask*)).ti,ab,hw.
60 (control* adj3 (study or studies or trial*)).ti,ab.
61 (Nonrandom* or non random* or non-random* or quasi-random* or quasirandom*).ti,ab,hw.
62 allocated.ti,ab,hw.
63 ((open label or open-label) adj5 (study or studies or trial*)).ti,ab,hw.
64 or/43-63
65 3 and 20 and 34
66 65
67 limit 66 to english language
68 3 and 20 and 42
69 3 and 20 and 64
70 68 or 69
71 exp animals/
72 exp animal experimentation/
73 exp models animal/
74 exp animal experiment/
75 nonhuman/
76 exp vertebrate/
77 or/71-76
78 exp humans/
79 exp human experiment/
80 or/78-79
81 77 not 80
82 70 not 81
83 82 not case reports.pt.
84 83
85 limit 84 to (english language and yr="2006 -Current")

 

OTHER DATABASES
PubMed Same MeSH, keywords, limits, and study types used as per MEDLINE search, with appropriate syntax used.
The Cochrane Library (Issue 1, 2011) Same MeSH, keywords, and date limits used as per MEDLINE search, excluding study types and human restrictions. Syntax adjusted for The Cochrane Library databases.

 

GREY LITERATURE SEARCHING
Dates for Search: February 25 to March 1, 2011
Keywords: Included terms for myocardial infarction and radionuclide imaging
Limits: English language

The following sections of the CADTH grey literature checklist, "Grey matters: a practical search tool for evidence-based medicine" (http://www.cadth.ca/en/resources/grey-matters) were searched:

  • Health Technology Assessment Agencies (selected)
  • Clinical Practice Guidelines
  • Databases (free)
  • Internet Search

 

Appendix 3: Non-invasive Criteria for Establishing Risk from the American College of Cardiology/American Heart Association/ Guidelines for the Management of Patients with Unstable Angina/ Non–ST-Segment Elevation Myocardial Infarction11

High risk (greater than 3% annual mortality rate)

  • Severe resting left ventricular (LV) dysfunction (left ventricular ejection fraction [LVEF] less than 0.35)
  • High-risk treadmill score (score -11 or less)
  • Severe exercise LV dysfunction (exercise LVEF < 0.35)
  • Stress-induced large perfusion defect (particularly if anterior)
  • Stress-induced multiple perfusion defects of moderate size
  • Large, fixed perfusion defect with LV dilation or increased lung uptake (thallium-201[201Tl])
  • Stress-induced moderate perfusion defect with LV dilation or increased lung uptake (201Tl )
  • Echocardiographic wall-motion abnormality (involving more than two segments) developing at low dose of dobutamine (10 mg per kg per minute or less) or at a low heart rate (less than 120 beats per minute)
  • Stress echocardiographic evidence of extensive ischemia

Intermediate risk (1% to 3% annual mortality rate)

  • Mild/moderate resting LV dysfunction (LVEF -0.35 to 0.49)
  • Intermediate-risk treadmill score (-11 to 5)
  • Stress-induced moderate perfusion defect without LV dilation or increased lung intake (201Tl )
  • Limited stress echocardiographic ischemia with a wall-motion abnormality only at higher doses of dobutamine involving less than or equal to two segments

Low risk (< 1% annual mortality rate)

  • Low-risk treadmill score (score 5 or greater)
  • Normal or small myocardial perfusion defect at rest or with stress
  • Normal stress echocardiographic wall motion or no change of limited resting wall-motion abnormalities during stress