The effects of lisinopril on renal function in proteinuric renal transplant recipients.

Renal transplantation is frequently accompanied by systemic hypertension. In the present study we evaluated the effect of 2.5 mg lisinopril in 12 hypertensive and proteinuric renal graft recipients with stable graft function over 3 months. Only patients with absence of renal artery stenosis, at least as judged by technetium-scan imaging, were included. Lisinopril was effective in lowering systemic blood pressure. Mean arterial pressure was unchanged despite reduction of concomitant antihypertensive medication. Mean serum creatinine was unchanged during the study (1.95 +/- 0.8 mg/dl in the pretreatment period vs. 1.77 +/- 0.76 mg/dl in the intervention period, n.s.). Glomerular filtration rate remained stable (62.75 +/- 21.96 vs. 60.17 +/- 18.27 ml/min/1.73 m2, n.s.) whereas renal plasma flow increased (224.75 +/- 91.66 vs. 244.92 +/- 94.13 ml/min/1.73m2, P < 0.01), leading to a drop in filtration fraction (31.4 +/- 12.4 vs. 26.8 +/- 8.6, n.s.). Renal vascular resistance was significantly reduced following angiotensin-converting enzyme (ACE) inhibitor therapy (26,447 +/- 14,574 vs. 23,425 +/- 12,430 dyne sec cm-5/1.73 m2, P < 0.01). Mean daily proteinuric decreased significantly (2.98 +/- 2.06 vs. 2.06 +/- 2.29 g, P < 0.01) whereas in a group of patients with comparable blood pressure but without ACE inhibitor therapy and similar degree of proteinuria, 24-hr proteinuria remained stable. No severe side effects were observed--in particular, mean serum potassium showed only a slight increase and no clinically significant hyperkalemic condition was observed. When lisinopril therapy was withdrawn after 3 months, blood pressure increased in all patients, requiring reinstitution of additional antihypertensive medication. Renal hemodynamic parameters and daily proteinuria returned to baseline values. We conclude that 2.5 mg lisinopril daily was safe and effective in this group of renal transplant recipients and showed a good antihypertensive as well as antiproteinuric effect.