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A metaanalysis of predischarge risk stratification after acute myocardial infarction with stress
L J Shaw1, E D Peterson, K Kesler
1Division of Cardiology, Duke University Medical Center, Durham, North Carolina 27705-4667, USA.
Insights
Predischarge non-invasive tests for myocardial infarction patients have low positive predictive value. Left ventricular dysfunction markers are better predictors of outcomes than ischemia markers.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Testing
Background:
- Risk stratification is crucial for post-myocardial infarction (MI) patients.
- Non-invasive testing is commonly used for risk assessment before hospital discharge.
- Previous studies have evaluated various non-invasive tests, but their predictive accuracy for long-term outcomes requires further clarification.
Purpose of the Study:
- To assess the relationship between abnormal predischarge non-invasive test results and outcomes in patients after myocardial infarction.
- To determine the sensitivity, specificity, and predictive values of various non-invasive tests for 1-year cardiac death or reinfarction.
Main Methods:
- Systematic review and meta-analysis of 54 studies published between 1980 and 1995.
- Included 19,874 post-MI patients with testing within 6 weeks of infarction and >80% follow-up rates.
- Calculated sensitivity, specificity, predictive values, and odds ratios for 1-year outcomes.
Main Results:
- Positive predictive values for most non-invasive risk markers were low (<0.10 for cardiac death, <0.20 for death or reinfarction).
- Markers of left ventricular dysfunction (e.g., exercise duration, ejection fraction) were more sensitive predictors than markers of ischemia (e.g., ST-segment depression, angina).
- One-year mortality varied by test type, ranging from 2.5% for stress echocardiography to 9.3% for radionuclide angiography.
Conclusions:
- The positive predictive value of predischarge non-invasive testing in post-MI patients is generally low.
- Left ventricular dysfunction markers appear more valuable for risk stratification than ischemia markers.
- Limitations in existing literature, including small sample sizes and variable event rates, necessitate more rigorous trials.
Abstract:
We assessed the relation of abnormal predischarge non-invasive test results to outcomes in postmyocardial infarction patients. We included series published from 1980 to 1995 containing only myocardial infarction patients, enrolling most patients after 1980, testing within 6 weeks of infarction, having follow-up rates > 80%, and having 2 x 2 frequency outcome rates for test results, that were the latest of multiple reports. Sensitivity, specificity, and predictive values were calculated for test results for 1-year outcomes (cardiac death, cardiac death or reinfarction). Univariable and summary odds were calculated for test results. Reports (n = 54) included a total of 19,874 patients and were primarily retrospective (76%) and small series (35% of reports included < 5 deaths). One-year mortality ranged from 2.5% for pharmacologic stress echocardiography to 9.3% for exercise radionuclide angiography. Positive predictive values for most noninvasive risk markers were < 0.10 for cardiac death and < 0.20 for death or reinfarction. Electrocardiographic, symptomatic, and scintigraphic risk markers of ischemia (ST-segment depression, angina, a reversible defect) were less sensitive (< or = 44%) for identifying morbid and fatal outcomes than markers of left ventricular dysfunction or heart failure (exercise duration, impaired systolic blood pressure response, and peak left ventricular ejection fraction). The positive predictive value of predischarge noninvasive testing is low. Markers of left ventricular dysfunction appear to be better predictors than markers of ischemia. Limitations of the literature-small samples and widely varying event rates-impede our ability to discern the accuracy of pre-discharge noninvasive testing. More rigorous, controlled trials are required to elucidate the relative value of these tests for risk stratification.