Endomyocardial Biopsy: Short- and Long-Term Safety in Myocarditis Patients.

Introduction: Aims of the study were to assess the short-term and long-term outcomes of percutaneous endomyocardial biopsy (EMB) in patients with myocarditis and to identify the risk factors for EMB-related complications in this patient population.

Methods: A retrospective analysis was conducted on 294 hospitalized patients with clinically suspected myocarditis at Tongji Hospital from October 2019 to October 2023, with a median follow-up duration of 18 months. Patients were divided into an EMB group (n = 151) and a non-EMB group (n = 143) based on whether they underwent EMB procedure. The incidence of endpoints was compared between the two groups, and the Kaplan-Meier survival curve was used to assess the survival rate without endpoints. Endpoints included major adverse cardiovascular events (MACE), ventricular enlargement, and decline in cardiac function. Multivariate logistic regression analysis was employed to evaluate the risk factors for EMB-related complications.

Results: The incidence of major short-term complications following EMB was 2.0% (3/151), while the incidence of minor complications was 9.3% (14/151). Multivariate risk regression analysis revealed that operative duration (OR: 1.101, 95% CI: 1.02-1.079, p < 0.05) and BNP levels (OR: 1.083, 95% CI: 0.931-1.26, p < 0.05) were associated with short-term complications following EMB. Compared to the non-EMB group, the EMB group had no significant increase in hospital stay (10 [8, 15] vs. 9 [7, 16], p = 0.27) and no significant decline in cardiac function. Long-term follow-up results showed that 8 patients (5.3%) in the EMB group experienced MACE, 14 patients (9.3%) had left ventricular enlargement, and 18 patients (11.9%) had a decline in left ventricular ejection fraction (LVEF) after discharge; in the non-EMB group, 12 patients (8.4%) experienced MACE, 30 patients (19.9%) had left ventricular enlargement, and 18 patients (11.9%) had a decline in LVEF after discharge. The Kaplan-Meier curve revealed a lower incidence of endpoint events in the EMB group (p < 0.05).

Conclusion: In patients with myocarditis, EMB is associated with a risk of short-term complications, with higher levels of BNP and operative duration being independent risk factors for EMB-related complications. However, EMB does not adversely affect cardiac function or hospital stay during the inpatient period and may contribute to the improvement of long-term outcomes in patients with myocarditis.