The effectiveness of various modes of nonsynchronized retrovenous perfusion in salvage of ischemic myocardium in the pig.

The effectiveness of intermittent coronary sinus occlusion was compared to a new non-electrocardiogram-synchronized coronary sinus retroperfusion system in terms of ability to reduce myocardial infarct size. In 40 anesthetized, open-chest pigs the left anterior descending coronary artery was occluded for 4 h and then reperfused for 1 h. In the arterial group, the coronary sinus was intermittently occluded (5 s inflation, 5 s deflation) with retroperfusion of arterial blood at 60 mL/min during balloon inflation. In the venous group, the protocol was identical to the arterial group except that venous blood was retroperfused at the same flow rate during balloon inflation. In the intermittent coronary sinus occlusion group, the coronary sinus was similarly occluded, but there was no active retroperfusion. In the control group, no intervention was performed. In the three experimental groups, retroperfusion was maintained throughout the 4 h occlusion period. Infarct size, assessed by tetrazolium staining and expressed as a percentage of the in vivo area at risk, was greater in control animals (86.3 +/- 7.5%) compared to either arterial (44.1 +/- 12.9%; P less than 0.001) or venous groups (57.7 +/- 15.5%; P less than 0.001) but not compared to the intermittent coronary sinus occlusion group (78.0 +/- 10.2%; not significant). Active retroperfusion with arterial blood did not achieve significantly greater salvage compared to active retroperfusion with venous blood (not significant), although both produced significantly greater salvage than intermittent coronary sinus occlusion (P less than 0.03). Mean coronary sinus pressure was 56.1 +/- 25.4, 38.8 +/- 5.6 and 17.1 +/- 6.4 mmHg in the arterial, venous and intermittent coronary sinus occlusion groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)