Can we improve the accuracy of risk assessment in patients with non ST-segment elevation acute coronary syndromes?

Background: In patients with non-ST segment elevation acute coronary syndromes (NSTE-ACS), the long-term risk of death and myocardial infarction (MI) is estimated by scores based on noninvasively derived variables. Much less is known about the relation between the degree of atherosclerotic burden in the coronary tree and the long-term risk of patients with NSTE-ACS. Aim: To evaluate the accuracy of a wide spectrum of coronary angiographic and clinical data in predicting outcomes in a long-term follow-up of patients successfully treated invasively for NSTE-ACS. Methods: The study group consisted of 112 consecutive patients (age 62 +/- 10 years; 76 men) treated invasively for NSTE-ACS. 27 (24%) patients had a history of diabetes mellitus (DM) and 37 (33%) patients a history of MI. The coronary angiograms prior to intervention were evaluated blindly for the four angiographic scores: (1) Stenosis score derived from the assessment of the degree of stenosis in 15 segments of the coronary tree; (2) Vessel score showing the number of main vessels stenosed > 70%; (3) Extensity score assessing the proportion of lumen length irregularity in 15 segments; and (4) Complexity score describing the number of complex plaques. The angiographic analysis also focused on the flow, presence of thrombus and collateral supply prior to intervention (according to TIMI) and the size of the culprit lesion vessel. The intervention was successful in 95% of cases. All patients were followed-up for 6-24 months for the occurrence of death or MI. Results: In the follow-up period, the composite end point of death or MI occurred in 20 (17%) patients. In order to indicate the risk predictors from the group of clinical and angiographic variables (age, sex, history of DM, history of MI, four angiographic scores and culprit lesion vessel characterisation), logistic regression analysis was performed. The independent angiographic predictors of composite end point (selected by forward conditional selection) were stenosis score (OR 1.13; 95% CI 1.05-1.2; p < 0.001) and size of the vessel (OR 0.08; 95% CI 0.01-0.6; p = 0.02) Conclusions: Our preliminary data shows that attempting to add angiographic variables into the risk assessment scoring systems in order to strengthen their predictive accuracy is justified.