We previously reported that heart transplant patients given cyclosporine for more than 2 years (short-term evaluation) had severe renal lesions and markedly reduced glomerular filtration rate and renal plasma flow (Kidney Int 40:243-250, 1991). We report the analysis of renal function in the same patients after 3 additional years of follow-up (long-term evaluation) while they continued to take cyclosporine. Since the previous evaluation, the dose of cyclosporine was adjusted to maintain stable trough levels and antihypertensive therapy was unchanged. The mean time-averaged dose of cyclosporine during the follow-up was 4.5 +/- 2.1 mg/kg/d. The systolic blood pressure at long-term evaluation (146 +/- 16 mm Hg) was increased (P < 0.05) compared with that at short-term evaluation (140 +/- 13 mm Hg), whereas diastolic blood pressure (long-term 91 +/- 9 mm Hg v short-term 88 +/- 9 mm Hg) and mean blood pressure (long-term 110 +/- 12 mm Hg v short-term 108 +/- 11 mm Hg) did not change significantly. Serum creatinine concentrations at long-term (1.7 +/- 0.3 mg/dL) and at short-term (1.7 +/- 0.4 mg/dL) evaluations were similar. At long-term evaluation the renal plasma flow (300 +/- 64 mL/min/1.73 m2) was not decreased compared with that at short-term evaluation (325 +/- 94 mL/min/1.73 m2), while the glomerular filtration rate increased significantly (43 +/- 15 mL/min/1.73 m2 v 36 +/- 8 mL/min/1.73 m2, respectively; P < 0.05). None of the patients became proteinuric after short-term evaluation; in those patients who were already proteinuric, urinary protein excretion did not increase over time.(ABSTRACT TRUNCATED AT 250 WORDS)