Global and regional haemodynamic effects of urapidil in conscious dogs with chronic coronary artery occlusion.
The haemodynamic effects of urapidil, an alpha 1-antagonist with central serotoninergic properties, were studied in an experimental canine model of chronic ischaemic heart disease. Global and regional haemodynamic recordings were made in conscious dogs with ameroid-induced single vessel coronary artery occlusion. Three intravenous bolus-infusion doses of urapidil (0.1 mg kg-1 + 0.3 mg min-1; 0.5 mg kg-1 + 1.5 mg min-1; 2.5 mg kg-1 + 7.5 mg min-1) were given on separate occasions in 12 animals. Regional blood flows were measured with radioactively labelled tracer microspheres. The effects of urapidil and dipyridamole, a powerful arteriolar vasodilator, on regional myocardial blood flow distribution to normal and collateral-dependent myocardium were compared. Urapidil caused a dose-dependent reduction of arterial blood pressure. There was moderate tachycardia and decreased left atrial filling pressures at the higher doses. Urapidil was a much weaker coronary vasodilator than dipyridamole. Dipyridamole caused maldistribution of intercoronary and transmural flows (endo-to-epicardial flow ratio in collateral-dependent regions from 1.35 +/- 0.07 to 0.7 +/- 0.13 and flow ratio between collateral-dependent and normal regions from 1.09 +/- 0.03 to 0.57 +/- 0.14). Urapidil preserved blood flow to both regions. Urapidil did not affect systolic wall thickening fraction in normal or ischaemic regions of the heart. Renal (+16%) and splanchnic perfusion (+45%) increased during urapidil infusion. Urapidil preserves myocardial function and perfusion and increases renal and intestinal blood flow in dogs with chronically ischaemic hearts.
Wouters
P F
PF
Department of Anaesthesiology, Universitaire Ziekenhuizen Gasthuisberg, Leuven, Belgium.
Marcus
M A
MA
Van Aken
H K
HK
van de Velde
M
M
Miserez
M
M
Deruyter
H A
HA
Mignolet
K
K
Flameng
W
W
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D016279:Atrial Function, Left / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D003097:Collateral Circulation / Q000187:drug effects; D003243:Consciousness / Q000502:physiology; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D004176:Dipyridamole / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D007422:Intestines / Q000098:blood supply; D017202:Myocardial Ischemia / Q000503:physiopathology; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D012079:Renal Circulation / Q000187:drug effects; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D013152:Splanchnic Circulation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D017366:Serotonin Receptor Agonists; D014665:Vasodilator Agents; D004176:Dipyridamole; C015568:urapidil