Beneficial effect of nisoldipine in repeated coronary reperfusion

BACKGROUNDWe have demonstrated that when repeated reperfusion is performed after reocclusion, there is a decrease in the amount of myocardial salvage, despite early reperfusion. It is unknown whether this deleterious effect of repeated reperfusion can be antagonized. Therefore, we studied the effect of nisoldipine (a dihydropyridine calcium antagonist) on infarct size, using a repeated-reperfusion model. METHODSThe left anterior descending coronary artery was occluded in anaesthetized dogs. Thirty minutes after occlusion, dogs were allocated randomly to either the treatment group (n = 6; 6 μg/kg per min nisoldipine infused intravenously throughout the experiment) or the control group (n = 8; saline). Occlusion was maintained for 2 h, followed by 1 h of reperfusion, then 1 h of reocclusion and 2 h of second reperfusion. An in vivo area at risk was determined by gentian-violet staining, and mfarct size was defined and quantitated by triphenyl-tetrazolium-chloride staining. RESULTSHaemodynamic measurements were similar in both groups. Mass of necrosis/mass at risk was significantly smaller in the nisoldipine group (33.3 ± 5.8%, mean ± SEM) compared with controls (46.8 ± 4.8%; P