Salvage of ischemic myocardium by nonsynchronized retroperfusion in the pig

Salvage of ischemic myocardium, with the aid of a nonsynchronized coronary sinus retroperfusion system, was studied in a pig infarct model. In anesthetized open chested animals, the left anterior descending coronary artery was occluded for 4 hours and then reperfused for 1 hour before the animals were killed. In the control group (n = 12) no therapy was used. In the experimental group (n = 13), nonsynchronized retrovenous coronary sinus perfusion was applied during the 4 hours of coronary artery occlusion. Therapy consisted of intermittent balloon occlusion of the coronary sinus (5-second inflation, 5-second deflation) with retroperfusion of arterial blood at 60 ml/min during the inflation part of the cycle. Infarct size, expressed as a percentage of the area at risk (+/- standard deviation), was significantly smaller in the experimental group (41.5% +/- 15.0%) than in the control group (80.5% +/- 6.1%) (p less than 0.001). Mean coronary sinus pressure (+/- standard deviation) was 51 +/- 12 mm Hg in the experimental group but was not elevated in the control animals. We conclude that nonsynchronized retrovenous coronary sinus perfusion was able to significantly salvage ischemic myocardium in a model of minimal intercoronary collateral circulation.