Late gadolinium enhancement on cardiac magnetic resonance imaging is associated with coronary endothelial dysfunction in patients with dilated cardiomyopathy.

Myocardial fibrosis and coronary endothelial dysfunction are important determinants of outcome in patients with heart failure. However, the relationship of these factors in patients with dilated cardiomyopathy (DCM) is not fully understood. This study aimed to investigate the relationship between endothelium-dependent coronary vasomotor abnormality and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) in patients with DCM. We examined 38 consecutive patients with DCM. All patients underwent CMR and the acetylcholine (ACh) provocation test using cardiac catheterization. During the ACh provocation test, we sampled blood simultaneously from the coronary sinus and aortic root to compare lactate concentrations, and quantified coronary blood flow volume using an intracoronary Doppler-tipped guidewire. LGE was detected in 17 (44.7%) patients. The lactate extraction ratio (LER) in the ACh provocation test was significantly decreased in the LGE-positive group (before vs after ACh, 18.6 ± 13.6 vs - 13.3 ± 24.8%; p < 0.001) and in the LGE-negative group (before vs after ACh, 14.2 ± 19.5 vs 3.3 ± 16.2%; p = 0.02). The rate of patients with an LER < 0% (indicating myocardial lactate production due to myocardial ischemia) was significantly higher in the LGE-positive group than in the LGE-negative group [12 (70.6%) vs 7 (33.3%); p = 0.02]. Multivariable logistic regression analysis showed that a post-ACh LER < 0% was a significant predictor of LGE positivity (odds ratio 7.75; 95% confidence interval 1.37-43.68; p = 0.02). In conclusion, ACh-provoked coronary vasomotor abnormality is associated with myocardial fibrosis in patients with DCM. These results suggest that coronary endothelial dysfunction is involved in myocardial fibrosis and worsening heart failure concomitant with DCM.