Comparative Effects ofACE Inhibitors and an Angiotensin Receptor Blocker on Atherosclerosis and Vascular Function

Background: Both angiotensin-converting enzyme inhibitors (ACE-IS) and angiotensin receptor blockers (ARBS) provide vascular protection. This study was designed to compare ACE-IS with widely differing tissue affinity (captopril and quinapril) and an ARB (losartan) on vascular protection against the adverse effects of high cholesterol. Methods and Results: Forty-two New Zealand rabbits on a 0.5 % cholesterol diet were ran-domized into control, captopril (10 mg/kg/d), quinapril (0.3 mg/kg/d), and losartan (8 mg/kg/d) groups for 14 weeks. Captopril, quinapril, and losartan significantly attenuated aor-tic lipid lesions (P = 0.001). Captopril and quinapril were more effective than losartan in pre-serving vascular relaxation. Conclusions: Captopril, quinapril, and losartan had similar protective effects against athero-genesis. Captopril and quinapril were more effective than losartan in preserving vascular function. Increased bradykinin by ACE inhibition may be responsible for this improved vas-cular endothelial function. Key words: angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, vascular function, atherosclerosis