Response and outcomes of cardiac resynchronization therapy in patients with renal dysfunction

Renal dysfunction is often associated with chronic heart failure, leading to increased morbi-mortality. However, data regarding these patients after cardiac resynchronization therapy (CRT) is sparse. We sought to evaluate response and long-term mortality in patients with heart failure and renal dysfunction and assess renal improvement after CRT.

We analyzed 178 consecutive patients who underwent successful CRT device implantation (age 64 ± 11 years; 69% male; 92% in New York Heart Association (NYHA) functional class ≥ III; 34% with ischemic cardiomyopathy). Echocardiographic response was defined as ≥ 15% reduction in left ventricular end-systolic diameter and clinical response as a sustained improvement of at least one NYHA functional class. Renal dysfunction was defined as an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m².

Renal dysfunction was present in 34.7%. Renal dysfunction was not an independent predictor of echocardiographic response (OR 1.109, 95% CI 0.713-1.725, p 0.646) nor clinical response (OR 1.003; 95% CI 0.997-1.010; p 0.324). During follow-up (mean 55.2 ± 32 months), patients with eGFR < 60mL/min/1.73 m² had higher overall mortality (HR 4.902, 95% CI 1.118-21.482, p 0.035). However, clinical response in patients with renal dysfunction was independently associated with better long-term survival (HR 0.236, 95% CI 0.073-0.767, p 0.016). Renal function was significantly improved in patients who respond to CRT (ΔeGFR + 5.5 mL/min/1.73 m² at baseline vs. follow-up, p 0.049), while this was not evident in nonresponders. Improvements in eGFR of at least 10 mL/min/1.73 m² were associated with improved survival in renal dysfunction patients (log-rank p 0.036).

Renal dysfunction was associated with higher long-term mortality in CRT patients, though, it did not influence echocardiographic nor functional response. Despite worse overall prognosis, renal dysfunction patients who are responders showed long-term survival benefit and improvement in renal function following CRT.