Endomyocardial Biopsy Utilization and Outcomes Among Patients with Myocarditis.

Right ventricular endomyocardial biopsy (EMB) is uncommonly used for patients admitted with myocarditis. In this study, we assessed the utilization of EMB and outcomes in patients admitted with myocarditis. We used the Nationwide Readmissions Database (NRD) from 2016 to 2019 to include patients ≥ 18 years of age with a primary diagnosis of myocarditis. Appropriate domain and Propensity Score (PS) analyses were applied using SAS 9.4. The outcomes were compared among patients who underwent EMB vs. those who did not. We included 11,927 cases of myocarditis, out of which only 378 patients (3.1%) had EMB. Patients who underwent EMB were older (mean age 45 vs. 41 years, p <0.01), more females (47% vs. 35%, p<0.01) compared to those who did not undergo EMB, respectively. Also, patients who underwent a biopsy, had higher rates of atrial fibrillation (19% vs. 7%), diabetes mellitus (18% vs. 11%), hypertension (40 vs. 34%), End-stage renal disease (4% vs. 1.3%), autoimmune disease (7% vs. 3%) and malignancy (13% vs. 3%) [p<0.01]. Patients who had EMB had higher incidence of cardiogenic shock (40% vs. 5%), ventricular tachycardia (30% vs. 7%), and sudden cardiac arrest (3.4% vs. 1.5%) [p<0.05]. They had higher inpatient mortality during index admission (5% vs. 1.5%), 30-day readmission (14% vs. 7%), hospitalization length (mean of 15 vs. 4 days), and charges ($367,801 vs. $63,726) [p<0.01]. After applying PS analysis and adjusting for comorbidities, age and gender did not affect survival. Although EMB is invasive, it seemed safe (not associated with increased mortality). (Figure 1) EMB was considered in very few selected critically ill patients admitted with myocarditis. EMB use was safe, although not associated with improved outcomes, most likely due to its limited use in the sicker population. Further studies are needed to determine the role of EMB in myocarditis patients. [ABSTRACT FROM AUTHOR]