Quantifying the effect of cardiorenal syndrome on mortality after left ventricular assist device implant.

BACKGROUND: Comorbidities complicate recovery and contribute to mortality after implant of a left ventricular assist device (LVAD). Coexistent cardiac and renal dysfunction (so-called cardiorenal syndrome) increases the risk of death, both with advanced heart failure and after LVAD implantation. We analyzed patients from the Interagency Registry for Mechanically Assist Circulatory Support to better estimate postimplant mortality according to the severity of renal dysfunction.
METHODS: Patients with a continuous-flow LVAD were grouped according to their pre-implant level of renal dysfunction: severe was defined as dialysis and/or estimated glomerular filtration rate (eGFR) < 30 ml/min; moderate if eGFR was 30 to 59 ml/min or blood urea nitrogen (BUN) was > 60 mg/dl; and mild or no renal dysfunction if eGFR was ≥ 60 ml/min and BUN was < 60 mg/dl.
RESULTS: Of the 4,917 patients with a continuous-flow LVAD implanted between June 2006 and March 2012, 3,160 (64%) were identified with mild or no renal dysfunction, 1,475 (30%) with moderate dysfunction, and 282 (6%) with severe dysfunction. Worsening renal dysfunction correlated with decreased survival, with nearly a 20% reduction in the 2-year survival going from low to severe dysfunction. The major negative survival effect occurred during the first 3 months. Combination of severe renal dysfunction and cardiogenic shock predicted the highest early mortality.
CONCLUSIONS: Pre-implant renal dysfunction predicts higher mortality after LVAD implant. The progressive reduction in survival with higher grades of renal dysfunction supports consideration of LVAD implant before cardiorenal syndrome is advanced. For patients with severe renal dysfunction and other major comorbidities, initial support with a temporary device while awaiting organ recovery before implanting a durable pump could be considered.