Long-term follow-up of ACE-inhibitor versus beta-blocker treatment and their effects on blood pressure and kidney function in renal transplant recipients

Abstract

Hypertension and nephrotoxicity are frequent complications of cyclosporine-induced immunosuppression in renal transplant recipients. Long-term antihypertensive treatment is obligatory for hypertensive transplant patients, to protect allograft function. The use of angiotensin-converting enzyme (ACE) inhibitors in the anti-hypertensive treatment of renal transplant recipients who receive immunosuppression with cyclosporine has long been discussed controversially. The aim of this prospective study, with a duration of 2 years and a follow-up of another 3 years, was to estimate the long-term antihypertensive potential of quinapril compared with that of the beta-blocker atenolol and to compare their effects on renal allograft function and proteinuria in 96 hypertensive renal transplant recipients who received cyclosporine A as immunosuppressive therapy. Patients were randomly assigned to receive either quinapril (group Q) or atenolol (group A) as anti-hypertensive treatment. Forty patients of each group completed the 5-year observation period according to protocol. Intention-to-treat and according-to-protocol analyses were performed. With the patients starting at similar baseline blood pressure values, both agents, atenolol and quinapril, decreased systolic and diastolic blood pressure (SBP, DBP) as well as middle arterial pressure (MAP) and pulse pressure (PP) to a similar extent (Delta SBP: group Q: -8+/-3 vs group A mmHg: -5+/-3; Delta DBP: -5+/-2 vs -4+/-2 mmHg; Delta MAP: -6+/-2 vs -5+/-2 mmHg; Delta PP: -2+/-2 vs -1+/-3 mmHg; mean +/- SEM). Neither serum creatinine levels nor Cockcroft-Gault clearance had changed significantly in either group after the 5-year period (Delta creatinine: 0.1+/-0.1 vs 0.2+/-0.2 mg/dl; Delta Cockcroft-Gault clearance: 3.9+/-4.6 vs 2.8+/-4.3 ml/min; mean +/- SEM). Urinary protein excretion remained stable among the quinapril-treated patients, whereas a significant increase was observed in the atenolol group during the 5-year study period (group Q: from 0.52+/-0.08 to 0.54+/-0.14 g/24 h; group A: from 0.34+/-0.03 to 0.72+/-0.13 g/24 h, P<0.02; mean +/- SEM). Albuminuria increased comparably in both groups, while the excretion of alpha-microglobuline increased slightly in the atenolol group, but decreased slightly in the quinapril group. The difference between the groups failed to be statistically significant (ANOVA, P<0.056). In conclusion, quinapril and atenolol may be considered suitable and safe substances in the long-term treatment of hypertensive renal transplant recipients, since both agents prove to be effective in anti-hypertensive treatment, and keep allograft function stable over a period of 5 years.