Response to cardiac resynchronization therapy in patients with heart failure and renal insufficiency

Renal insufficiency (RI) adversely impacts prognosis in heart failure (HF) patients, partly because renal and cardiac dysfunction are intertwined, yet few cardiac resynchronization therapy (CRT) studies have examined patients with moderate-to-severe RI.

We analyzed 787 CRT-defibrillator (CRT-D) recipients with a glomerular filtration rate (GFR) measured prior to implant. Patients were grouped by GFR (in mL/min/1.73 m(2)): >or=60 (n = 376), 30-59 (n = 347), and <30 (n = 64). Overall survival, changes in left ventricular (LV) ejection fraction and LV end-systolic diameter, and GFR change at 3-6 months were compared among CRT-D groups and with a control cohort (n = 88), also stratified by GFR, in whom LV lead implant was unsuccessful and a standard defibrillator (SD) was placed. All patients met clinical criteria for CRT-D.

Among CRT-D recipients, overall survival improved incrementally with higher baseline GFR (for each 10 mL/min/1.73 m(2) increase, corrected hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.13-1.30, P < 0.0001). Survival among SD and CRT-D patients within GFR < 30 and GFR >or= 60 groups was similar, whereas CRT-D recipients with GFR 30-59 had significantly better survival compared to SD counterparts (HR 2.23, 95% CI 1.34-3.70; P = 0.002). This survival benefit was associated with improved renal and cardiac function. CRT recipients with GFR >or= 60 derived significant echocardiographic benefit but experienced a GFR decline, whereas those with GFR < 30 had no echocardiographic benefit but did improve GFR.

CRT may provide the largest survival benefit in HF patients with moderate RI, perhaps by improving GFR and LV function. Severe baseline RI predicts poor survival and limited echocardiographic improvement despite a modest GFR increase, such that CRT may not benefit those with GFR < 30 mL/min/1.73 m(2). CRT recipients with normal renal function derive echocardiographic benefit but no overall survival advantage.