Matching between regional coronary vasodilator capacity and corresponding circumferential strain in individuals with normal and increasing body weight

Abstract

Background: To define the relationship between regional coronary vasodilator capacity and myocardial circumferential strain at rest in normal weight, overweight, and obese individuals with normal global left-ventricular function.

Methods and results: Myocardial blood flow at rest and during pharmacologic vasodilation was measured with (13)N-ammonia PET/CT in mL/g/minute in normal weight control (CON, n = 12), overweight (OW, n = 10), and obese individuals (OB, n = 10). In addition, resting myocardial function was evaluated as circumferential strain (Єc, %) by MRI. Global myocardial flow reserve (MFR) did not differ significantly between CON and OW (2.98 ± 0.96 vs 2.70 ± 0.66, P = .290), whereas it declined significantly in OB (1.98 ± 1.04, P = .030). Further, global Єc (%) was comparable between CON, OW, and OB (-0.24 ± 0.03, -0.23 ± 0.02, and -0.23 ± 0.04) but it was lowest in OB when normalized to the rate-pressure product (NЄc: -0.31 ± 0.06, -0.32 ± 0.05, and -0.26 ± 0.08). When MFR of the three major coronary territories was correlated with corresponding Єc, a positive association was observed in CON (r = 0.36, P = .030), in OW (r = 0.54, P = .002), and also in OB when relating NЄc to coronary vascular resistance during pharmacologic vasodilation (r = -0.46, P = .010).

Conclusions: Higher coronary vasodilator capacity is related to corresponding regional circumferential strain at rest in non-obese individuals, while this is also observed for reduced MFR in obesity.