The risk of cardiovascular death following the first acute ischaemic syndrome: experience in Kaunas between 1997 and 2001

Abstract

The aim of our study was twofold: initially to investigate the effects of the informative value of the variables of the acute period on the risk of cardiovascular death during the long-term period following the first acute coronary syndrome, and then to determine the long-term survival rate in different risk groups.

Methods — The prospective five-year observational study included 732 patients with acute coronary syndrome who had survived the hospital period. Employing multivariable Cox’s proportional-hazard analysis, the most informative variables were selected, the risk score index was calculated, the risk groups for the prediction of cardiovascular death were identified, long-term survival (4.5 ± 2.1 years) in different risk groups was determined and internal validation of the model was performed.

Results — During the observational period, 84 patients (11.5%) died due to cardiovascular causes. Cox proportional-hazard models demonstrated that six variables had significant influence on long-term survival during the five-year period after an acute coronary syndrome. These variables were: age [1-5 points], the presence of pathologic Q wave in > 2 ECG leads [2 points], Killip class II-IV [24 points], left ventricular ejection fraction < 35% [2-4 points], proximal stenosis of coronary arteries [2-4 points], absence of myocardial revascularization in the acute period [2 points].Three strata for risk of cardiovascular death were identified [0-5 points - 14.1% patients, 6-10 points - 62.6%, > 10 points - 23.3%].The probability of survival within the period of five years was found to be favourable for the majority of patients in the low- and medium-risk groups, while the number of such patients in the high-risk group was significantly lower [97.0% vs. 89.0% vs. 73.0%, P< 0.0000].The difference in the survival probability was negligible in developmental and validation sets.

Conclusion — The risk score derived from clinical variables of first acute coronary syndromes permits a reliable determination of risk for cardiovascular death as well as the prediction of long-term survival in different risk groups.

Key Words:

• acute coronary syndrome
• risk for cardiovascular death
• long-term survival