Beneficial effect of HEPES buffer in repeated coronary reperfusion

Background We have demonstrated previously that, when repeated reperfusion is performed after reocclusion, there is a decrease in the amount of myocar dial salvage, despite early reperfusion, Treatment with nisoldipine induced a beneficial effect by reduction of infarct size in this experimental mode l. Objective To study the effect of HEPES buffer on infarct size, using a repe ated-reperfusion model. Methods The left anterior descending coronary artery was occluded in anesth etized dogs. Thirty minutes after the occlusion, dogs were allocated random ly to either the treatment group (n = 7; HEPES 0.64 mmol/l infused intraven ously throughout the experiment) or the control group (n = 8; saline). Occl usion was maintained for 2 h, followed by 1 h of reperfusion, then 1 h of r eocclusion and 2 h of second reperfusion. An in-vivo area at risk was deter mined by gentian violet staining, and infarct size was defined and quantita ted by triphenyl-tetrazolium chloride staining. Results Hemodynamic measurements were similar in both groups. Mass of necro sis/mass at risk was significantly smaller in the HEPES group (30.7 +/- 1.6 % mean +/- SEM) compared with controls (50.6 +/- 3.8%, P < 0.001). Conclusion Treatment with HEPES induces a beneficial effect by reduction of infarct size in repeated coronary reperfusion. Coronary Artery Dis 11:1 79 -182 (C) 2000 Lippincott Williams & Wilkins.