Impairment of Coronary Flow Reserve Evaluated by Phase Contrast Cine‐Magnetic Resonance Imaging in Patients With Heart Failure With Preserved Ejection Fraction

Background Phase contrast ( PC ) cine‐magnetic resonance imaging ( MRI ) of the coronary sinus allows for noninvasive evaluation of coronary flow reserve ( CFR ), which is an index of left ventricular microvascular function. The objective of this study was to investigate coronary flow reserve in patients with heart failure with preserved ejection fraction ( HF p EF ). Methods and Results We studied 25 patients with HF p EF (mean and SD of age: 73±7 years), 13 with hypertensive left ventricular hypertrophy ( LVH ) (67±10 years), and 18 controls (65±15 years). Breath‐hold PC cine‐ MRI images of the coronary sinus were obtained to assess blood flow at rest and during ATP infusion. CFR was calculated as coronary sinus blood flow during ATP infusion divided by coronary sinus blood flow at rest. Impairment of CFR was defined as CFR HF p EF patients had decreased CFR . CFR was significantly decreased in HF p EF patients in comparison to hypertensive LVH patients and control subjects ( CFR : 2.21±0.55 in HF p EF vs 3.05±0.74 in hypertensive LVH , 3.83±0.73 in controls; P ANOVA ). According to multivariable linear regression analysis, CFR independently and significantly correlated with serum brain natriuretic peptide level (β=−68.0; 95% CI, −116.2 to −19.7; P =0.007). Conclusions CFR was significantly lower in patients with HF p EF than in hypertensive LVH patients and controls. These results indicated that impairment of CFR might be a pathophysiological factor for HF p EF and might be related to HF p EF disease severity.