Abstract 15094: Prevalence of Coronary Microvascular Dysfunction in Women With Angina and No Obstructive Coronary Artery Disease: Preliminary Results From the iPower Study

Abstract

Background: Women are more often than men found to have no obstructive coronary artery disease (CAD) when evaluated with a coronary angiogram (CAG) due to angina pectoris and suspected ischemic heart disease. Coronary microvessel dysfunction (CMD) is a possible explanation, and can be assessed by transthoracic Doppler echocardiography (TTDE) with measurement of coronary flow reserve (CFR). Reduced CFR carries an adverse prognosis despite absence of obstructive CAD. The aim of the ongoing iPower study is to evaluate CFR in women with angina pectoris and no obstructive CAD. Methods: Women with angina pectoris and a CAG without obstructive coronary artery disease (>50%) are systematically invited to participate. Assessment includes demographic and clinical data, blood samples and TTE during rest and high-dose dipyridamole stress (0.84mg/kg) with measurement of CFR by Doppler of the left anterior descending artery. Results: To date (May 21st 2014) 3500 women have been screened (flowchart), 793 women have been included (response rate 23%). Mean age was 62.4 (+/-9.6) and the burden of risk factors was relatively high (Table 1). CFR was successfully measured in 763 patients (96%). Median (IQR) CFR was 2.4 (2.0-2.8). Cut-off point for CMD of both 2 and 2.5 has been used previously. In this population, 214 (28%) had a CFR≤2 and 468 (61%) a CFR≤2.5. Conclusions: To our knowledge, iPower is the largest and most comprehensive study systematically assessing CMD in women with angina pectoris and no obstructive CAD. Non-invasive CFR assessment is feasible, and microvascular function impaired in a large proportion. Future follow-up will determine the prognostic value of CFR as a measure of CMD.