Elevated lymphatic vessel density measured by Lyve-1 expression in areas of replacement fibrosis in the ventricular septum of patients with hypertrophic obstructive cardiomyopathy (HOCM).

Lymphatic microvessel density (LMVD) contributes to fibrosis in patients with myocardial infarction. However, the role of LMVD in the process of myocardial fibrosis in hypertrophic obstructive cardiomyopathy (HOCM) patients is unclear. We studied LMVD in ventricular septal (VS) samples from 52 individuals (42 was HOCM patients who underwent a transaortic extended septal myectomy, and 10 traffic accident victims), and examined the relationships between the LMVD stained immunohistochemically with lymphatic vessel endothelial hyaluronan receptor (LYVE-1) antibodies, collagen volume fraction (CVF), and clinical characteristics. Compared with traffic accident victims, LMVD was significantly increased in VS of HOCM patients (132.0 ± 49.0 VS 57.8 ± 48.8/mm2, p = 0.000). HOCM patients with syncope had higher level of LMVD than without syncope [166.7 (131.0-201.1) VS 116.4 (80.7-152.1)/mm2, p = 0.017], and LMVD were positively correlated with Log (CVF) (r = 0.431, p = 0.004). On multiple variables regression analysis, LMVD was independently associated with Log (CVF) (r = 0.379, p = 0.009) and syncope (r = 0.335, p = 0.020). In conclusions, the LYVE-1-positive lymphatics have close associations with VS fibrosis in HOCM patients.