Coronary artery plaque burden is a predictor of myocardial ischemia in non-ST elevation myocardial infarction in both genders

Abstract

Purpose: Women with non-ST elevation myocardial infarction (NSTEMI) have less obstructive coronary artery disease, but the same extent of myocardial ischemia. This may be explained by larger coronary artery plaque burden and tortuosity. The impact of these factors on myocardial ischemia is not entirely known in NSTEMI patients. Methods: In 108 patients (age 67±12 years, 32% women) hospitalized with NSTEMI, coronary artery plaque burden and tortuosity (≥3 curves >45°) was assessed by quantitative coronary angiography. Significant coronary artery stenosis was defined as lumen diameter reduction of ≥ 50%. The extent of myocardial ischemia was assessed by myocardial contrast echocardiography using a 17 segment left ventricular (LV) model. Results: Women with NSTEMI had the same total coronary artery plaque burden as men (35.1±21.8 vs. 43.2±21.3mm2, p=ns) and the same extent of myocardial ischemia (6.9±3.7 vs. 7.2±3.7 LV segments, p=ns). More women had non-significant coronary artery stenoses (27 vs. 10%, p<0.05) and tortuous coronary arteries (82% vs. 61%, p<0.05). There were no significant differences in age (70±12 vs. 66±12 years), prevalence of hypertension (44% vs. 43%) or diabetes (21% vs. 19%) between genders (all ns). Coronary artery plaque burden, significant coronary artery stenosis and age all predicted larger extent of myocardial ischemia independent of gender, tortuosity, diabetes and hypertension in multiple linear regression analysis (Multiple R2= 0.25, all p<0.01) (Table). View this table: Table 1. Predictors of extent of myocardial ischemia in NSTEMI Conclusions: Total coronary artery plaque burden is an independent predictor of myocardial ischemia in NSTEMI patients. The mismatch between coronary artery stenosis and myocardial ischemia previously found in women with NSTEMI cannot be explained by differences in coronary artery tortuosity or plaque burden.