Typical Chest Pain and Normal Coronary Angiogram: Cardiac Risk Factor Analysis Versus PET for Detection of Microvascular Disease

摘要

id="p-1">Angiography of patients with typical chest pain reveals normal epicardial coronary arteries in about 20%. Coronary flow reserve (CFR) determination is an elaborate, but helpful, task, as only the evidence of microvascular disease enables appropriate therapy. We prospectively evaluated the incidence of a dysfunctional microcirculation and searched for predictive parameters of a reduced CFR. >Methods: In 79 consecutive patients (52 females, 27 males) with typical angina and a normal angiogram and 10 control subjects (6 females, 4 males), CFR was measured by 13N-ammonia rest/dipyridamole PET and correlated with clinical parameters individually and summarized as the number of risk factors (NRF) using an elaborated cardiac risk factor score. >Results: Sixty-five percent of patients had a reduced CFR (CFR 2.5). CFR correlated with NRF (r = 0.55, P 0.001), systolic blood pressure (r = 0.46, P 0.001), interventricular septal thickness (r = 0.33, P 0.01), and age (r = 0.25, P = 0.02). Eighty-five percent of patients with a high risk factor score (NRF a‰￥ 5) had a reduced CFR. In contrast, 100% of our patients with a low risk factor score (NRF 2) presented a normal CFR. In total, 55% of our patients could be allocated to either one of these groups. >Conclusion: In about two thirds of patients, anginal pain can be explained by a reduced CFR. Risk factors have a cumulative negative effect on CFR. A clinical cardiac risk factor analysis enables estimation of individual probability of microvascular dysfunction in a significant proportion of these patients. However, CFR measurements are recommended for those with an intermediate NRF.