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Prognostic cardiac catheterization variables in survivors of acute myocardial infarction: a five year prospective
S P Schulman1, S C Achuff, L S Griffith
1Divison of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Insights
Prognostic factors from cardiac catheterization, including coronary artery stenoses and ejection fraction, predict future cardiac events in acute myocardial infarction survivors. Angiographic data significantly improves risk stratification over five years.
Area of Science:
- Cardiology
- Clinical Medicine
- Medical Diagnostics
Background:
- Survivors of acute myocardial infarction (AMI) require prognostic assessment to guide long-term management.
- Predischarge coronary angiography and left ventriculography provide valuable data for risk stratification.
Purpose of the Study:
- To evaluate prognostic variables from predischarge cardiac catheterization in AMI survivors.
- To identify significant predictors of cardiac events over a 5-year follow-up period.
Main Methods:
- Prospective follow-up of 143 AMI survivors for 5 years.
- Analysis of clinical and angiographic variables using Kaplan-Meier curves and multivariate Cox's hazard function.
- Definition of a 'risk segment' as myocardium supplied by a stenosed coronary artery (>50% stenosis).
Main Results:
- Right plus left anterior descending coronary artery stenoses, ejection fraction, and presence of risk segments were significant predictors of outcome.
- Angiographic variables significantly added to clinical variables in predicting cardiac events.
- Only 7% of patients had severely depressed left ventricular function (ejection fraction ≤29%).
Conclusions:
- Cardiac catheterization provides additive prognostic information in AMI survivors.
- These findings aid in stratifying long-term cardiac risk over 5 years.
- Risk stratification can be enhanced by combining clinical and angiographic data.
Abstract:
The prognostic variables from predischarge coronary angiography and left ventriculography in survivors of acute myocardial infarction during the years 1974 to 1978 were evaluated in 143 patients (less than or equal to 66 years of age) with documented myocardial infarction who were then followed up prospectively for 5 years. One half of the study population had triple vessel coronary disease (greater than or equal to 50% stenosis). However, only 7% of patients had severely depressed left ventricular function with an ejection fraction less than or equal to 29%. Evaluation of the contribution of many clinical and angiographic variables to a first cardiac event (death, nonfatal reinfarction or coronary artery bypass surgery) was considered with Kaplan-Meier actuarial curves and multivariate Cox's hazard function analysis. A risk segment was defined as an area of contracting myocardium supplied by a coronary artery with a greater than 50% stenosis. Multivariate analysis demonstrated that right plus left anterior descending coronary artery stenoses (p less than 0.01), ejection fraction (p less than 0.01) and the presence of risk segments (p less than 0.05) were significant predictors of outcome. Furthermore, on separate multivariate analyses, the angiographic variables added significantly to the clinical variables to predict cardiac events over 5 years of follow-up. Therefore, in survivors of acute myocardial infarction who undergo cardiac catheterization, additive prognostic information is obtained that can be used to stratify risk over 5 years.