EXPERIMENTAL OFF-PUMP GRAFTING OF A CIRCUMFLEX BRANCH VIA STERNOTOMY USING A SUCTION DEVICE

Background. We have shown previously in the pig that coronary artery b ypass grafting on the beating heart may be facilitated by local cardia c wall immobilization by a suction device (''Octopus'') applied to the anterolateral side of the heart. The purpose of this study was to inv estigate the feasibility of the method on the posterolateral side. Met hods. In a consecutive series of 8 pigs, after median sternotomy, the posterior wall was taken hold of by the Octopus and subsequently broug ht up anteriorly and immobilized while hemodynamics were monitored. A posterolateral branch of the circumflex artery was grafted with the le ft internal mammary artery. After the coronary artery was ligated prox imally, the heart was repositioned. At 6 weeks, bypass graft angiograp hy and functional testing (postocclusion hyperemia testing) were perfo rmed. After sacrifice, histologic examination of the anastomosis was p erformed. Results. Dislocation of the heart to expose the distal anast omosis site caused a minor drop in mean arterial blood pressure from 7 1 +/- 14 (baseline) to 63 +/- 6 mm Hg (dislocated) (not significant) a nd recovery to 70 +/- 12 mm Hg, 15 minutes after repositioning. Cardia c output decreased from 4.0 +/- 1.0 to 3.2 +/- 0.7 L/min (p = 0.02) an d recovered to 4.3 +/- 0.3 L/min. No inotropic drugs were necessary. A nastomosing required 21.5 +/- 6.5 minutes. Baseline graft now was 8 +/ - 3 mL/min and increased threefold to 24 +/- 10 mL/min (p < 0.05) at p ostocclusive hyperemia testing. At sacrifice after 6 weeks (n = 8), gr aft flow increased fourfold from 5 +/- 2 to 20 +/- 8 mL/min (p = 0.002 ) (n = 7). At histologic examination all eight anastomoses were patent without stenosis or mural thrombus. Conclusions. Off-pump coronary ar tery bypass grafting of the posterolateral circumflex branches using t he Octopus method on the beating pig heart is feasible, with full pate ncy maintained for at least 6 weeks. (C) 1997 by The Society of Thorac ic Surgeons.