Determinants of coronary arterial flow-mediated dilatation following percutaneous coronary intervention

It has previously been observed that coronary diameter may increase following relief of flow-limiting obstruction. Flow mediated dilatation (FMD) is a fundamental adaptive mechanism for arteries, which is dependent on intact endothelial function. We thus aimed to characterize whether the degree of this flow-mediated dilatation was related to risk factors, which may impair endothelial function.

We measured coronary diameter with quantitative angiography before and after relief of chronic total or subtotal (>or=99%) occlusion in 171 patients, in which TIMI-0 or TIMI-1 flow was rapidly restored to TIMI-3 (with attendant increase in flow hypothesized to result in FMD).

Of the 171 patients, 73% were male, 62% were current or ex-smokers, 47% were diabetic, 53% had hypertension, 64% had dyslipidemia (documented hypercholesterolemia or total cholesterol >5.0 mg/dL) and 65% were taking statin therapy.

Mean vessel diameter was 2.8 +/- 0.7 mm and flow-mediated dilatation measured 15.1% +/- 20.1% in target vessel, compared with 1.6 +/- 3.1 in control vessels (P < 0.05). FMD was strongly and inversely related to baseline vessel diameter (r = -0.48, P < 0.001). The degree of vessel dilation correlated negatively with the presence of diabetes (r = -0.33, P < 0.001), smoking (r = -0.30, P < 0.001) and extent of coronary artery disease (CAD, r = -0.17, P = 0.01) and positively with the use of statins (r = 0.27, P = 0.001). These factors, apart from extent of CAD, remained significant predictors of FMD on multivariate analysis.

FMD occurs in human coronary arteries following restoration of flow. The magnitude of FMD appears related to vascular risk factors and their treatment.