The relationship between collateral blood flow and infarct zone regional wall motion in patients with recent acute myocardial infarction

Abstract

After acute myocardial infarction (AMI), the most significant prognostic determinants of myocardial viability and function are deterioration degree of the distal myocardial microcirculation and collateral flow. Quantification of coronary collateral circulation is possible by using intracoronary pressure measurement techniques. We hypothesized that quantitatively determined coronary wedge pressure (CWP) and collateral flow index (CFI) may be useful in order to designate regional left ventricular function and indirectly viability after MI. In this study, we investigated the relationships between angiographically quantified wall motion scores and CWP and CFI in patients with recent AMI and treated with thrombolytic therapy. Forty patients early after myocardial infarction with ≥60% residual stenosis in infarct related artery (IRA) after thrombolysis, who underwent PTCA and/or stent implantation for this culprit lesion, were included in this study. None of the patients had significant stenosis in other coronary arteries. Angiographic ventricular wall motion scoring (WMS) was performed semi quantitatively according to coronary artery surgery study criteria. After angiography, fiberoptic pressure monitoring guide wire (pressure wire, Radi) was positioned distal to the stenosis to be dilated. During complete occlusion with balloon inflation distal pressure recorded as CWP. CFI was determined as the ratio of simultaneously measured CWP to aortic pressure. The mean values of CWP, CFI and mean WMS were 18.1 ± 7.9 mmHg, 0.18 ± 0.09 and 3.15 ± 0.8, respectively. The CWP (r: −0.86) and CFI (r: −0.84) values correlated well with WMS determined in the infarcted territory. We concluded that collateral circulation in the infarcted region is related to the left ventricular regional function. Presence of adequate and intact collateral network in the infarct related segments diminishes microvascular damage translating into preserved left ventricular regional functions.