Feasibility and safety of percutaneous laser revascularization using the Biosense system in porcine hearts.

Abstract

Direct myocardial revascularization (DMR) is being explored to improve symptoms in patients with refractory ischemic coronary syndromes. This study assessed the safety and feasibility of percutaneous DMR using the Biosense non-fluoroscopic navigation system (incorporating the holmium : yttrium aluminium garnet laser) in pig hearts. Twenty pigs underwent left ventricular mapping using the Biosense system, followed by percutaneous DMR with a holmium : yttrium aluminium garnet laser at 2 J x 1 pulse, and were sacrificed acutely (n = 5), at 24 h (n = 5), and at 3 weeks (n = 10) after the DMR procedure. The hearts were examined grossly and microscopically. Serial creatine kinase-MB level was measured up to 24 h. There were no procedural complications. Animals received 13 +/- 2 channels in 19 +/- 7 min. The catheter was able to reach all regions, including the septum. There was no increase in creatine kinase-MB level up to 24 h. One animal died within an hour of the procedure. There was one sealed perforation into the subepicardial fat as a result of same site laser activation. Histologic evaluation in the acute and 24 h groups revealed laser channels which were 3.6 +/- 2.2 mm long, 1.5 +/- 0.7 mm wide, with an entry angle of 73 +/- 12 degrees. Channels were filled with platelet thrombi acutely and were surrounded by well-defined rims of thermal coagulation and an 'impact zone' of viable myocardium; at 3 weeks, no channels remained patent and they had been replaced by well-healed granulation tissue. It is feasible and safe to perform percutaneous DMR with the Biosense system and the channels created with the chosen laser parameters are rapidly sealed with platelet thrombi and at 3 weeks are replaced by well-healed granulation tissue.