Dialytic Support in Patients with Acute Renal Failure with Implantable Left Ventricular Assist Devices

Abstract

The left ventricular assist device (LVAD), used thus far as a bridge to heart transplantation, may offer an alternative to heart transplantation. Because patients receiving LVADs are in cardiogenic shock, many experience acute ischemic renal failure in the peri-implantation period. We describe 10 patients who underwent dialysis after receiving LVADs for end-stage heart disease. Among 37 patients who received an LVAD, 10 required dialytic support (8 men, 2 women; mean age, 47.3 ± 11.3 yr; mean APACHE II score at ICU admission, 18.0 ± 4.7). Renal replacement therapy was started for fluid removal within 48 hours of LVAD implantation in 8 patients. Continuous renal replacement therapy (CRRT) was the first-line modality for 9 patients, including 3 slow continuous ultrafiltrations (SCUF), 4 continuous venovenous hemofiltrations (CWH), 5 continuous venovenous hemodiafiltrations (CWHD), 2 continuous arteriovenous hemofiltrations (CAVH), and 1 continuous arteriovenous hemodiafiltration (CAVHD). Patients remained on CRRT for a mean of 14.4 ± 6.1 days, and 5 were eventually changed to intermittent hemodialysis. The mean time on renal replacement therapy was 27.8 ± 19.7 days. During CRRT, despite daily average ultrafiltration of 3,445 ± 623 mL, net fluid loss was only 358 ± 507 mL/day. Metabolic control achieved with CRRT, expressed as mean ± SD, was: BUN 75.5 ± 13.0 mg/dL (26.9 ± mmol/L), serum creatinine 4.0 ± 0.7 mg/dL (354 ± 62 mmol/L), carbon dioxide content (bicarbonate plus dissolved CO₂) 21.5 ± 1.7 mEq/L, and serum electrolytes within normal limits. Survival for patients with LVADs who did not require dialysis was 93% compared with 40% for the group with combined LVADs and dialytic support. The 4 patients who survived in the dialysis group all recovered renal function, and their need for dialysis ceased within 18 to 33 days. Mean serum creatinine levels at follow-up after transplantation were 2.0 ± 1.0 mg/dL (177 ± 88 mmol/L). In conclusion, CRRT provides good metabolic control and allows large ultrafiltration volume in patients supported by an implantable LVAD. We observed a 40% survival rate in patients with combined LVADS and dialytic support, and the survivors all recovered renal function.