Impact of renal insufficiency on long-term clinical outcome in patients with heart failure treated by cardiac resynchronization therapy

Abstract

BackgroundRenal insufficiency is recognized as a predictor of mortality and adverse outcome in heart failure (HF) patients. However, the long-term clinical outcome of cardiac resynchronization therapy (CRT) in Japanese HF patients with renal insufficiency remains uncertain. MethodsWe evaluated 67 consecutive patients who underwent CRT at our hospital. The patients were divided into two groups according to a baseline estimated glomerular filtration rate (e-GFR) cut-off value of 50ml/min, which is defined as the time at which patients should be referred to a nephrologist, by the Japanese Society of Nephrology. Follow-up echocardiographic findings and renal function were examined at 3–6 months after CRT. Then, we compared long-term clinical outcomes between the two groups, and analyzed the effect of CRT on renal function, echocardiographic parameters and cardiac survival. ResultsDuring a mean follow-up period of 30.3 months, patients with advanced renal insufficiency (e-GFR<50ml/min) had significant higher all-cause mortality (log-rank p=0.033) and higher cardiac mortality combined with HF hospitalization (log-rank p=0.017) than patients with e-GFR≥50ml/min. Multivariate analysis revealed that advanced renal insufficiency was an independent predictor of cardiac mortality combined with HF hospitalization (odds ratio=3.01, p=0.008). Subgroup analysis in the baseline advanced renal insufficiency group revealed that patients with preserved renal function by CRT (<10% reduction in e-GFR) had a higher rate of decrease of left ventricular end-systolic diameter (−14.0% vs. −0.8%, p=0.023) and lower cardiac mortality combined with HF hospitalization (log-rank p=0.029) compared with patients with deterioration of renal function (≥10% reduction in e-GFR). ConclusionsThe present study suggests that advanced renal insufficiency is quite useful for the prediction of worsening clinical outcomes in HF patients treated by CRT. Preservation of renal function by CRT brings about better cardiac survival through prevention of adverse cardiac events, even in HF patients with advanced renal insufficiency.