Short ischemia causes endothelial dysfunction in porcine coronary vessels in an in vivo model

Background. The aim of this study was to evaluate the effects of a short pe riod of ischemia (10 mins) and a prolonged period of ischemia (60 mins) fol lowed by reperfusion on coronary flow changes induced by acetylcholine (ACh ), adenosine (ADO), and endothelin (ET). Methods. The left anterior descending coronary artery in anesthetized pigs was occluded for 10 or 60 minutes followed by 120 minutes reperfusion. Ther eafter, the now changes in the left anterior descending coronary artery wer e studied after intracoronary infusion of ACh, ADO, and ET. Results. Short-term ischemia (10 minutes) caused a decrease in vasodilatati on, but not the vasoconstriction response to ACh. Prolonged ischemia (60 mi nutes) impaired ADO induced vasodilatation and aggravated ET evoked vasocon striction. Conclusions. The present findings suggest that a short period of ischemia ( 10 minutes) causes disturbances of the endothelial regulation of coronary v ascular tone and that this endothelial regulation is more sensitive, and pr ecedes changes in vascular smooth muscle function after ischemia and reperf usion. (Ann Thorac Surg 2001;71:265-9) (C) 2001 by the Society of Thoracic Surgeons.