Safety and efficacy of a novel gel for vascular occlusion in off-pump surgery

Purpose. Coronary occlusion techniques used during off-pump coronary artery bypass surgery often provide suboptimal visualization and can damage the endothelium. We evaluated a novel gel with reverse thermosensitive properties for internal vessel occlusion during off-pump coronary artery bypass surgery. Description. Yorkshire pigs (n = 6 per group) underwent two cycles of mid-left anterior descending coronary artery (LAD) occlusion using the gel (injected into the artery) or microvascular clamps (control group) followed by 30 minutes of reperfusion. Regional wall motion and LAD flow were monitored, microvessel relaxation responses were evaluated, and myocardial tissue was analyzed histologically. Evaluation. Complete left anterior descending coronary artery occlusion was successfully achieved using the gel (median ischemic time, 14 minutes; range, 4.5 to 24 minutes). Anterior wall motion abnormalities as well as flow patterns in the reperfused left anterior descending coronary artery were similar in both groups. Microvessel relaxation to substance P was mildly impaired (-11.7 ± 2.8% vs control; p < 0.001) in the left anterior descending coronary artery territory, but response to adenosine diphosphate and sodium nitroprusside was unaffected. Mild contraction band necrosis was present in both groups, consistent with mild ischemia-reperfusion injury. Conclusions. The gel represents a safe and effective method of vessel occlusion with a potentially important role in off-pump coronary artery bypass surgery.