Left and right coronary circulation in left ventricular hypertrophy: effects of angiotensin converting enzyme inhibition.
The circulation in the left and right coronary beds in pressure overload-induced left ventricular (LV) hypertrophy was studied in Wistar male rats (n=6/group) that were subjected to abdominal aortic constriction or to sham-operation. From 3 to 6 weeks after surgery, the animals with aortic constriction received vehicle or 0.01, 0.1, or 1 mg/kg per day po of the angiotensin converting enzyme (ACE) inhibitor, ramipril. At 6 weeks, after measuring blood pressure in the carotid artery in vivo, the hearts were isolated and the left and right coronary beds subjected to independent perfusion. Minimum coronary vascular resistance per unit heart weight (MCVR/g) was determined in both beds during simultaneous infusion of 10 micromol/L adenosine. Aortic constriction resulted in a significant increase in blood pressure, LV weight/body weight ratio, and bilateral MCVR/g. Ramipril lowered arterial pressure in a dose-dependent manner and reversed the increased right MCVR/g at the anti-hypertensive dose, but it did not affect LV mass or left MCVR/g. These results suggest that both coronary hypertension and myocardial hypertrophy contribute to the global impairment of coronary circulation in LV hypertrophy. ACE inhibitors may improve coronary circulation in LV hypertrophy when administrated at an appropriate dose and for a sufficient period.
Shimada
Yasuyuki
Y
Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Japan. yasuyuki.shimada@ma8.seikyou.ne.jp
Avkiran
Metin
M
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D017379:Hypertrophy, Left Ventricular / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D009206:Myocardium / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D017257:Ramipril / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D014655:Vascular Resistance / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A; D017257:Ramipril