Short-term oral treatment with the angiotensin II receptor antagonist losartan does not improve coronary vasomotor function in asymptomatic type 2 diabetes patients

Background: We have previously found that acute intravenous infusion of an ACE inhibitor normalized the reduced coronary vasomotor function in type 2 diabetes. The aim of the present study was to extend this investigation to an angiotensin II receptor blocker (ARB) administered orally in normotensive, asymptomatic type 2 diabetes patients without albuminuria. Results: Fourteen type 2 diabetes patients were included. Each patient had myocardial perfusion measured by PET at three occasions: at baseline, following 3 weeks of treatment with 50 mg/d and following another 3 weeks of treatment with 100 mg/d of losartan. Baseline myocardial perfusion was similar at all three sessions (0.89 ± 0.05, 0.90 ± 0.08 and 0.84 ± 0.05 mL/(min g) tissue, respectively). Likewise, maximal hyperaemic perfusion after i.v. dipyridamole (0.56 mg/kg bwt) was low but similar at the three sessions (2.01 ± 0.14, 2.05 ± 0.17 and 1.90 ± 0.20 mL/(min g) tissue, respectively). Myocardial perfusion reserve, i.e. maximal hyperaemic flow relative to baseline flow, was also low, but similar before and after treatment with losartan (2.36 ± 0.24, 2.44 ± 0.24 and 2.62 ± 0.42 mL/(min g) tissue, respectively). Conclusions: Oral treatment with an ARB did not normalize coronary vasomotor function in type 2 diabetes patients without cardiovascular disease.