Hyperosmotic mannitol and collateral blood flow to ischemic myocardium.
Elevation of extracellular osmolality reduces the extent of myocardial and endothelial cell swelling that accompanies acute ischemia, and the reduction of cell swelling is associated with an increase in collateral blood flow to the ischemic area. However, little is known about the effects of hyperosmolality on the vascular resistance of the collateral coronary vasculature. We compared the effects of hyperosmolar mannitol with those of nitroglycerin and dipyridamole on the vascular resistance of large collateral coronary vessels and of the small arterial vasculature in an isolated heart model of regional ischemia. Elevation of osmolality by mannitol increased collateral blood flow to the ischemic region through at least two mechanisms. First, increasing osmolality resulted in dilation of large arterial conductance vessels, similar to that produced by nitroglycerin. In addition, mannitol produced an effect on the coronary circulation at a microvascular level which, per se or in combination with its effect on larger collateral conductance vessels, increased collateral blood flow to ischemic regions.
Vlahakes
G J
GJ
Department of Surgery (Cardiac Surgical Unit), Massachusetts General Hospital, Boston.
Giamber
S R
SR
Rothaus
K O
KO
Powell
W J
WJ
D000818:Animals; D003097:Collateral Circulation / Q000187:drug effects*; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000503:physiopathology; D004176:Dipyridamole / Q000494:pharmacology; D004285:Dogs; D005260:Female; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D009994:Osmolar Concentration; D014655:Vascular Resistance / Q000187:drug effects
D008353:Mannitol; D004176:Dipyridamole; D005996:Nitroglycerin