Impact of Kidney Function on the Survival of Patients with Chagas Cardiomyopathy and Implantable Cardioverter Defibrillators

Background/Objectives: Impaired kidney function significantly increases mortality in recipients of implantable cardioverter defibrillators (ICDs). However, in the landmark studies evaluating ICDs and cardiac resynchronization therapy with a defibrillator (CRT-D) for the treatment of heart failure (HF) with a reduced ejection fraction (HFrEF), patients with Chagas cardiomyopathy (CC) have been underrepresented. This study aimed to determine whether kidney dysfunction has the same negative impacts on patients with ICDs or CRT-Ds and CC. Methods: We prospectively followed patients with CC and left ventricular ejection fractions (LVEFs) of ≤40% who underwent ICD or CRT-D implantation and had at least one prior creatinine measurement. The primary outcome was the survival rate during follow-up. Variables with a p of <0.10 from the univariate analysis were selected for inclusion in the Cox regression model. Results: A total of 343 patients were enrolled, with a median follow-up duration of 777 days. The mean age was 60.2 (±11.2) years. Fifty percent of patients were observed to have a New York Heart Association (NYHA) functional class of III, and the median left ventricular ejection fraction (LVEF) was 27% (22-32). Overall mortality events occurred in 113 (32.9%) participants during follow-up. Although the estimated glomerular filtration rate (eGFR) was significantly associated with survival in the univariate analysis [HR 0.98 (CI 95% 0.98-0.99), p = 0.007], it did not retain significance in the multivariate model [HR 0.99 (0.98-1.00), p = 0.138], which was adjusted for age, gender, atrial fibrillation (AF), body mass index (BMI), and the use of digoxin, furosemide, anticoagulants, and LVEF. Conclusions: Unlike other cardiomyopathies, impaired eGFR was not an independent predictor of mortality in this cohort of CC patients undergoing ICD or CRT-D implantation, possibly due to the distinctive pathophysiological mechanisms of the disease. These findings suggest that clinicians should not be discouraged from recommending CIEDs in patients with CC and moderately impaired kidney function, although further studies are warranted to assess outcomes in those with advanced CKD.