PROGNOSTIC-SIGNIFICANCE OF PROGRESSION OF CORONARY ATHEROSCLEROSIS

Background. Angiographic progression of coronary atherosclerosis is frequently observed in clinical practice and is used as an end point in clinical trials; however, its prognostic significance is unclear. Methods and Results. Progression defined as an increase in diameter stenosis by greater-than-or-equal-to 15% of at least one coronary lesion was seen in 141 (42%) of 335 patients who underwent repeat coronary arteriography after a 2-year interval as part of clinical trial. Coronary lesions were measured quantitatively from comparable end-diastolic frames selected by a radiologist viewing each pair of films together. During a mean follow-up of 44+/-10 months after the second arteriogram, cardiac death occurred in 19 patients (5.7%), cardiac death or nonfatal infarction was seen in 40 cases (11.9%), and 90 patients (26.9%) underwent coronary revascularization. At least one end point event occurred in 112 of the 335 patients. Sixteen of the 19 cardiac deaths were in progressors, a relative risk of 7.3 (95% Cl, 2.2-24.7; p < 0.001). The relative risk of cardiac death or nonfatal infarction for progressors was 2.3 (1.3-4.2, p=0.009) and of any cardiac event was 1.7 (1.3 -2.3, p < 0.001). A stepwise multivariable Cox regression model of time to event was used to assess the relative contribution of progression as a predictor of coronary events. Low ejection fraction (p=0.001), progression (p=0.001), and hypertension (p=0.011) were retained as predictors of cardiac death. Angina and the number of diseased vessels were the strongest predictors of revascularization. Conclusions. Coronary progression is a strong, independent predictor of future coronary events, particularly cardiac death, and its use as a surrogate end point in clinical trials is justified.