Tenascin-C and Fibrosis as Prognostic Predictors of Peripartum Cardiomyopathy　- A Histopathological Study

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening condition. The histological characteristics of PPCM as risk factors for poor outcomes have not been thoroughly investigated. This study evaluated the pathological findings of PPCM, with a particular focus on inflammatory factors such as tenascin-C (TNC) and interleukin-6, which may predict left ventricular dysfunction and the prognosis of PPCM.

We conducted a retrospective single-center observational study involving endomyocardial biopsies (from 27 patients) as clinically diagnosed PPCM. We assessed the association between the histology and cardiac events, namely cardiac death, left ventricular assist device implantation, and/or heart transplantation. During the median follow-up period of 2,100 days, 7 (25.9%) composite events were documented. Kaplan-Meier survival curves demonstrated that patients with advanced cardiac fibrosis had significantly poorer long-term outcomes than those with mild cardiac fibrosis (log-rank P=0.0003). Furthermore, TNC-positive patients with advanced fibrosis had significantly worse event-free survival than TNC-negative patients with advanced fibrosis and patients with mild fibrosis (Bonferroni-adjusted P=0.016 and P<0.0001, respectively). Interleukin-6 expression was higher in cardiac tissue from PPCM patients who were TNC positive (P=0.03).

Cardiac histopathology in PPCM patients can predict long-term prognosis; both advanced fibrosis and immunohistochemical TNC expression are associated with poor prognosis.