Prognostic Value of Coronary Flow Reserve in Asymptomatic Moderate or Severe Aortic Stenosis with Preserved Ejection Fraction and Nonobstructed Coronary Arteries

Aim: Patients with moderate and severe aortic stenosis (AS) and without obstructive epicardial coronary disease have been shown to have an impairment of coronary flow reserve (CFR). We investigated the prognostic significance of CFR in predicting death during mid‐to‐long‐term follow‐up in asymptomatic patients with moderate/severe AS, preserved ejection fraction (EF), and with nonobstructed coronary arteries. Method and Result: A total of 127 patients with moderate or severe AS (effective orifice area of 1.5 cm² or less), mean age 66 ± 11 were enrolled in this prospective study. The median follow‐up was 32 ± 7 months. All patients had standard Doppler echo study, coronary angiography, and adenosine‐stress transthoracic Doppler echo for CFR measurement. Univariate analysis showed that diabetes mellitus, CFR, aortic valve area (AVA), maximal velocity (V_max), mean pressure gradient (P_mean), energy loss index (ELI), aortic valve resistance (AVR), NT‐proBNP, E/E′, valvulo‐arterial impedance (Z_va), and stroke work loss (SWL) were associated (P < 0.05) with death. Multivariable logistic regression analysis revealed that only Z_va and CFR were independent predictors of death, with the CFR being the single strongest predictor (Table 2). Using receiver operating characteristics (ROC) analysis, the CFR value of 1.85 had the highest accuracy in predicting the death during mid‐to‐long‐term follow‐up (area under the curve; AUC 0.890, P = 0.009, sensitivity 96.3%, specificity 75%; 95% CI 0.287–0.946; Fig. 1). The Z_va value of 5.52 Hg/mL per m had a sensitivity 70.0% and specificity 72.0% (AUC 0.766, 95% CI 0.587–0.946; P = 0.005). Conclusion: This study demonstrates that CFR has a prognostic value in patients with asymptomatic moderate or severe AS with preserved EF and nonobstructed coronary arteries.