Improvement in renal function after left ventricular assist device placement

Background: Worsening renal function is a common consequence of heart failure (HF), and may be improved with circulatory support. The efficacy of left ventricular assist device (LVAD) support to reverse renal insufficiency in end-stage HF has not previously been quantitatively reported, and would be useful to aid in decision-making regarding utilization of LVAD support in the context of bridge-to-transplant (BTT) and destination therapy. Methods: We addressed this question using data derived from 220 patients who underwent Novacor LVAD placement from 1996–03 (190 for BTT and 30 as destination therapy). Creatinine clearance (CrCl), calculated using the Cockroft-Gault formula, was compared among all surviving hospitalized patients who had renal function assessed pre-operative (n = 220), at 1 (n = 203), 2 (n = 178), 3 (n = 81), and 4 weeks (n = 82) after implant. Paired (same patient, different date) sample t test analyses were then performed for each successive time interval. Similar analyses were performed for patients with baseline CrCl <50 ml/min. Results: Baseline serum creatinine was 1.6±0.7 mg/dl; 60 of patients had CrCl <50 ml/min at implant. Creatinine clearance rose significantly within the first week in the overall study population, from 76.6±46.1 ml/min to 91.8±51.2 ml/min at one week and to 114.9±63.8 ml/min by three weeks. Secondary analysis evaluated patients for whom both pre- and post-implant values were available. This paired sample analysis showed a similar effect (77.0±46.6 pre-implant, rising to 92.1±51.1 ml/min at week 1 (n = 202;p<0.01), and from 89.4±49.2 to 95.2±52.4 ml/min (n = 171;p = 0.01) between weeks 1 and 2. Similar analysis among those with baseline CrCl <50 ml/min showed that the CrCl rose from 36.7±9.2 to 60.1±35.5 (n = 55; p<0.01) from pre-implant to week 1 and from 59.7±36.8 to 66.8±47.3 ml/min (n = 47; p = 0.15) from week 1 to 2. Thirty-seven of the 60 patients with CrCl <50 ml/min (62%) on intra-aortic balloon pump support pre-implant also showed significant improvement in CrCl after LVAD implantation. Overall, 41 of 60 patients (68%) with CrCl <50 improved their creatinine clearance to >50 ml/min during the first 4 weeks after surgery. Conclusion: In patients selected for bridge or destination LVAD support, majority of the patients who demonstrate renal insufficiency that would exclude them from traditional transplant candidacy on the day of LVAD implantation, exhibited substantial improvement in renal function over the first month after device implantation.