Orthotopic heart transplantation (OHT) is an accepted treatment for heart failure refractory to medical management. International registry data reported a 1-year survival after OHT of 79%. The risk factors associated with requiring continuous venovenous hemofiltration or hemodialysis and mortality in patients requiring continuous venovenous hemofiltration (CVVH)/hemodialysis (HD) have not been studied, since improvements have been made in OHT. We tested the hypothesis that requiring CVVH/HD in the immediate posttransplantation period increases mortality after OHT. We studied pretransplantation factors to predict those patients who would need CVVH/HD. Patients undergoing OHT from 1995 to 1996 were studied. Fifty-two patients underwent OHT. Eight patients (15%) needed CVVH/HD. Initial immunosuppression included cyclosporine, azathioprine, and solumedrol. Patients were changed to antilymphocyte therapy if they had oliguric acute renal failure, T or B cell incompatibility, or biopsy-proven rejection. Overall, survival at 1 year was 84.6%. Survival in patients not needing CVVH/HD was 91%, and survival in patients needing CVVH/HD was 36.5%. For each year of age over 55 years, patients had a relative risk of requiring CVVH/HD of 7. (Am J Kidney Dis 1998 Aug;32(2):290-4)