Abstract Background Idiopathic dilated cardiomyopathy (DCM) is associated with poor long-term prognosis. Prognostic stratification is important to manage patients with DCM. Late gadolinium enhancement (LGE) evaluated by cardiac magnetic resonance (CMR) is known as a prognostic marker, however, it remains insufficient. Recently, coronary microvascular dysfunction (CMD) is related to adverse cardiovascular events in patients with cardiovascular disease. The Clinical relevance of CMD in patients with DCM is uncertain. Purpose We investigated the relationship between LGE and CMD, and impact of CMD on long-term prognosis in patients with DCM. Methods Patients with DCM who underwent both CMR and coronary angiography were consecutively enrolled. CMD was evaluated by angiography-derived index of microcirculatory resistance (angio-IMR) of left anterior descending artery. Primary endpoint was composite outcome of 3-year all-cause mortality or heart failure hospitalization. Results Among 108 patients (female of 26.6%, mean age of 62.1 years old, mean left ventricular ejection fraction of 33%), composite outcome occurred in 18% (19 patients). The median angio-IMR was 45 (35–56) and LGE was seen in 23% (25 patients). Angio-IMR was significantly higher in LGE positive group than in LGE negative group (52.0 vs 42.5, p = 0.03). Patients were stratified into two groups by median angio-IMR, patients with high angio-IMR had significantly higher incidence of composite outcome than in those with low angio-IMR (27.8% vs. 7.4%, log-lank test p 0.01, Figure 1). When patients were stratified by combination with angio-IMR and LGE, there were significant differences in composite outcome among three groups (low angio-IMR and LGE negative: 4.3% vs. high angio-IMR or LGE positive: 22.2% vs. high angio-IMR and LGE positive: 41.2%, log-lank test p 0.01, Figure 2). Conclusion CMD evaluated by angio-IMR was associated with LGE and long-term prognosis in patients with DCM. Further investigation is needed to elucidate relationship among CMD, LGE and prognosis.
Kawamura et al. (Sat,) studied this question.