Microvascular Dysfunction in Patients with Idiopathic Dilated Cardiomyopathy: Quantitative Assessment with Phase Contrast Cine MR Imaging of the Coronary Sinus

Purpose: The purposes of this study were to compare global coronary flow reserve (CFR) between patients with idiopathic dilated cardiomyopathy (DCM) and risk-matched controls using cardiac MRI (CMR), and to evaluate the relationship between global CFR and CMR left ventricular (LV) parameters. Methods: Twenty-six patients with DCM and 26 risk-matched controls who underwent comprehensive CMR examination, including stress-rest coronary sinus flow measurement by phase contrast (PC) cine CMR were retrospectively studied. LV peak global longitudinal, radial, and circumferential strains (GLS, GRS, and GCS) were determined by feature tracking. Results: Patients with DCM had significantly lower global CFR compared with the risk-matched controls (2.87 +/- 0.86 vs. 4.03 +/- 1.47, P= 0.001). Among the parameters, univariate linear regression analyses revealed significant correlation of global CFR with LV end-diastolic volume index (r = -0.396, P= 0.045), LV mass index (r = -0.461, P= 0.018), GLS (r = -0.558, P= 0.003), and GRS (r = 0.392, P= 0.047). Multiple linear regression analysis revealed GLS as the only independent predictor of global CFR (standardized beta= -0.558, P= 0.003). Conclusion: Global CFR was significantly impaired in patients with idiopathic DCM and independently associated with LV GLS, suggesting that microvascular dysfunction may contribute to deterioration of LV function in patients with idiopathic DCM.