Background: In the absence of obstructive coronary disease (<50% diameter stenosis; NOCAD), coronary microvascular dysfunction, manifested as reduced ability to increase myocardial perfusion with increasing oxygen demand, is the possible explanation for recurrent angina and adverse cardiovascular prognosis. We hypothesized that symptomatic women with NOCAD have reduced myocardial perfusion reserve (MPR) evaluated with cardiac computed tomography (CT) perfusion (CTP) compared to healthy sex-matched reference population.
Methods: We included women with angina and NOCAD on invasive coronary angiography (cases; n=109) and a sex-matched reference population (controls; n=34) without history of angina, coronary heart disease, and NOCAD on coronary CT angiography. A semi-quantitative assessment of MPR, defined as the relative difference of perfusion before and after adenosine-induced vasodilation, was performed by static CTP.
Results: Cases were on average 4 years older (p=0.04) and had a higher burden of risk factors (2±1 vs. 1±1; p<0.001). Cases showed a tendency towards higher basal perfusion and lower hyperemic perfusion, compared to controls. The ability to increase global and regional myocardial perfusion during adenosine-induced vasodilation was significantly lower in cases compared to controls (Table). This remained unchanged when adjusting for age, risk factors and presence of coronary atheromatosis.
Conclusion: Women with angina and NOCAD have impaired microvascular function, manifested as reduced MPR.