梗塞責任血管における再灌流後の冠微小循環障害の検討 : 冠予備能と冠コンダクタンスによる評価

Abstract

Previous studies have utilized coronary flow reserve (CFR) to evaluate coronary microcirculation. However, the limitations of CFR in the assessment of coronary microcirculation have been well described. Recently, coronary conductance can be mea- sured in patients with ischemic heart disease. Measurements of coronary conductance are obtained from the slope of the instantaneous end-diastolic relation between coronary flow velocity and atrtic pressure using spectral analysis of the intracoronary Doppler signal. It has been reported that coronary conductance may be able to evaluate coronary microcir- culation less affected by hemodynamic conditions than CFR. The purpose of this study was to investigate whether evaluation of coronarry microcirculation in the infarct related artery by coronary conductance is more useful than CFR. We studied 15 anterior myocardial infarction patients with single vessel disease. Follow-up coronary angiography was performed 3 months after successful direct angioplasty, where no restenosis occurred. In the acute phase and chronic phase, we assessed the phasic coronary flow velochity pattern of the infarct related artery (IRA) and the non-infarcted artery (NIA) using a 0.014-inch Doppler guidewire (FloWire, Cardiometrics, Inc.) at rest and during hyperemia induced by intravenous administration of adenosine triphosphate disodium (150 μg/kg/min). CFR was obtained from the hyperemic/baseline flow velocity ratio. We also calculated coronary conductance at rest and during hyperemia. As a result, the CFR values were found to be lower in the IRA than the NIA in the acute phase. However, in the chronic phase there were no significant differences between the CFR values obtained in the IRA and in the NIA. The recovery of CFR in the IRA was sufficient 3 months after successful direct angioplasty. There were no significant differ- ences between coronary conductance at rest in the IRA and in the NIA, although coronary conductance during hyperemia was lower in the IRA than the NIA both in the acte and chronic phases. The recovery of coronary conductance in the IRA was insufficient 3 months after successful direct angioplasty. These results have been taken to suggest that impair- ment of coronary microcirculation in the IRA remains for a period of 3 months after successful direct angioplasty.