Background: Implantable cardioverter-defibrillator (ICD) implantation is often an elective outpatient procedure, but previous studies have shown that approximately 30% are performed during acute hospitalizations.
Purpose: This study aims to identify predictors of acute hospitalization versus elective outpatient ICD implantation and evaluate differential clinical outcomes.
Methods: We studied 327 first-time ICD recipients between 2011 and 2015. All patients receiving a primary prevention ICD were optimized on guideline directed medical therapy (GDMT) prior to consideration for device implantation. Using multivariate logistic regression, we examined predictors of ICD implantation during acute hospitalization. Cox proportional hazard regression was used adjusting for patient characteristics to examine associations with clinical outcomes including complications, device therapy, heart failure re-admission, and death.
Results: Of all patients, 132 (40.3%) underwent ICD implantation during acute hospitalization, most frequently performed for secondary prevention (n = 76, 57.6%). The most common reason for acute hospitalization ICD implantation in primary prevention patients was an indication for pacing (n = 20, 35.7%). In multivariable adjusted models, secondary prevention indication, non-single chamber device, NYHA class IV symptoms, lower diastolic blood pressure, higher BUN, and lower hemoglobin were significant predictors of ICD implantation during an acute hospitalization. In univariate analysis, acute hospitalization ICD implantation was associated with a higher risk of heart failure re-admission (HR = 1.6, 95% CI 1.1-2.4) and mortality (HR = 3.0, 95% CI 1.1-8.0) but no difference in risk of ICD therapy (HR = 1.4, 95% CI 0.9-2.3) or adverse events (HR = 1.1, 95% CI 0.6-2.1). After multivariable adjustment for potential confounders, all outcomes were no different between acute hospitalization versus elective outpatient ICD recipients.
Conclusions: Among first-time ICD recipients, specific clinical characteristics predicted acute hospitalization ICD implantation. After adjustment for potential confounders, acute hospitalization ICD implantation was not associated with increased risk of morbidity or mortality.
Keywords: Acute hospitalization; Implantable cardioverter-defibrillator; Inpatient; Mortality; Outcomes; Outpatient; Predictors.