P2.C045: Risk of Adverse Events Following Outpatient Carvedilol Dose Titration in Pediatric and Young Adult Patients with Dilated Cardiomyopathy

Background: Nonselective beta blockade with carvedilol is a key component of heart failure management in pediatric dilated cardiomyopathy. Due to the risk of bradycardia and hypotension following administration, some practitioners prefer to monitor for adverse events following dose titration in the outpatient setting. We sought to determine the incidence and risk factors for adverse events following outpatient carvedilol dose titration in pediatric patients with dilated cardiomyopathy.

Methods: This was a single center, retrospective review of 116 carvedilol dose titrations among 48 patients with dilated cardiomyopathy aged 0-26 years old. Data including patient demographics, anthropometrics, left ventricular internal diameter in diastole (LVIDd) Z score, ejection fraction (EF), fractional shortening (FS), severity of mitral regurgitation, and carvedilol dosing was collected. Heart rate and blood pressure monitoring data every 15 minutes for one hour after carvedilol dose titration was reviewed for any adverse events, defined as signs and symptoms of bradycardia and hypotension. Inpatient carvedilol titrations were excluded. Following Shapiro-Wilk testing for normality, the Mann Whitney test compared continuous variables and Fisher’s exact test compared categorical variables. A p value of < 0.05 was considered significant.

Results: Of 48 patients with median (IQR) age of 4 (1.4-14) years, 18 (37.5%) were male. Seven of 48 (14.6%) patients experienced an adverse event and 8 of 116 (6.9%) dose titrations were associated with an adverse event. Moderate and severe mitral regurgitation portended a greater risk of adverse events (moderate: 25.0% vs 13.0%; severe: 25.0% vs 6.5%, p = 0.0495). There were no significant differences in patient sex, race/ethnicity, LVIDd Z score, EF, FS, and carvedilol dosing between patients who experienced adverse events and those who did not.

Conclusion: Outpatient carvedilol dose titration was associated with a low adverse event rate in our cohort of pediatric and young adult patients with dilated cardiomyopathy. Moderate and severe mitral regurgitation were associated with an increased risk of adverse events. These findings can be used to better identify patients at risk for adverse events following outpatient carvedilol dose titration. Additionally, these findings can inform quality improvement initiatives in cardiology clinic workflow and resource utilization.