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Survival of medically treated patients in the coronary artery surgery study (CASS) registry
Insights
Survival rates for obstructive coronary artery disease patients significantly decrease with more diseased vessels. Left ventricular function is a more critical predictor of survival than the number of affected coronary arteries.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Public Health
Background:
- Obstructive coronary artery disease (CAD) affects millions globally.
- Assessing survival predictors in CAD is crucial for patient management.
- Left ventricular (LV) performance is a key factor in cardiovascular health.
Purpose of the Study:
- To evaluate the impact of obstructive coronary artery disease extent on patient survival.
- To determine the influence of two left ventricular (LV) performance measures on survival.
- To analyze survival rates in medically managed patients with varying degrees of obstructive CAD.
Main Methods:
- Analysis of 20,088 patients without prior coronary artery bypass graft surgery from the National Heart, Lung, and Blood Institute Coronary Artery Surgery Study registry (1975-1979).
- Evaluation of cumulative 4-year survival rates in medically managed patients.
- Assessment of obstructive coronary artery disease severity (number of diseased vessels, left main disease) and LV performance (ejection fraction, systolic contraction pattern score).
Main Results:
- Four-year survival for medically treated patients decreased from 97% (no disease) to 68% (three-vessel disease).
- Left main coronary artery disease significantly reduced survival, particularly in three-vessel disease patients (70% to 60%).
- LV ejection fraction and contraction pattern scores were more significant predictors of survival than the number of diseased vessels. For instance, patients with poor LV function (score 17-30) had 4-year survival rates of 42% for three-vessel disease, compared to 79% for those with good LV function.
Conclusions:
- The extent of obstructive coronary artery disease negatively impacts survival.
- Left ventricular function is a more critical determinant of long-term survival in patients with obstructive coronary artery disease than the number of diseased vessels.
- These findings underscore the importance of assessing LV performance in risk stratification and treatment planning for CAD patients.
Abstract:
The objective of this study was to evaluate the impact on survival of the anatomic extent of obstructive coronary artery disease and of two measures of left ventricular (LV) performance. This study is based on 20,088 patients without previous coronary artery bypass graft surgery who were enrolled in the registry of the National Heart, Lung, and Blood Institute Coronary Artery Surgery Study from 1975 to 1979. The cumulative 4-year survival of medically managed patients was analyzed to determine the survival of specific subsets of patients with obstructive coronary disease. The vital status of 99.8% of the patients was known. The 4-year survival of medically treated patients with no significant obstructive disease was 97%, in contrast to 92%, 84% and 68% in patients with one-, two- and three-vessel disease, respectively. The presence of left main coronary artery disease decreased survival significantly. The 4-year survival decreased from 70% to 60% in patients with three-vessel disease when significant obstruction of the left main coronary artery was also present. Patients with significant coronary artery disease who had an ejection fraction of 50--100%, 35--49%, and 0--34% had a 4-year survival of 92%, 83% and 58%, respectively. The systolic contraction pattern was assessed in five selected segments and given a score of 1--6, with a score of 1 for normal function, increasing to 6 if an aneurysm was present. In a patient with normal LV contraction in all five segments of the LV ventricular angiogram, the LV score would equal 5. Patients with an LV score of 5--11, 12--16 and 17--30 had 4-year survivals of 90%, 71% and 53%, respectively. Patients with good LV function (a score of 5--11) had a 4-year survival of 94%, 91% and 79% for one-, two- and three-vessel disease, respectively. Patients with poor left ventricular function (score of 17--30) had a 4-year survival rate of 67%, 61% and 42% in one-, two- and three-vessel disease, respectively. Thus, LV function is a more important predictor of survival than the number of diseased vessels.