Different Microcirculation Response Between Culprit and Non-Culprit Vessels in Patients With Acute Coronary Syndrome

Background This study investigated whether the microvascular dysfunction differed between culprit and non-culprit vessels in patients with acute coronary syndrome who underwent percutaneous coronary intervention. Methods and Results In 115 prospectively recruited patients, after successful percutaneous coronary intervention, culprit and non-culprit intracoronary hemodynamic measurements were performed and repeated at 6-month follow-up. N-ammonia positron emission tomography was performed at 6-month follow-up visit to determine absolute myocardial blood flow. The resistance values of each vessel were calculated using the coronary pressure data and the myocardial blood flow values obtained from N-ammonia positron emission tomography data. We compared the measurements between culprit and non-culprit vessels and assessed changes in microvascular dysfunction during the study period. In 334 vessels (115 culprit and 219 non-culprit), the culprit vessel group showed a lower fractional flow reserve and coronary flow reserve than the non-culprit vessel group at baseline and 6-month follow-up, respectively. The value of index of microcirculatory resistance was different between the 2 groups in the baseline but not at 6-month follow-up. The microvascular resistance at rest and hyperemic microvascular resistance were not different between the 2 groups, but resistance to stenosis was higher in the culprit vessel group, under both resting and hyperemic status ( =0.02 and