Effects of transmyocardial laser revascularization by using a prototype pulsed CO2 laser on contractility and perfusion of chronically ischemic myocardium in a porcine model

The purpose of this study was to test a new prototype pulsed CO2 laser to b e used for transmyocardial laser revascularization (TMR). We wanted to dete rmine whether it can reduce thermal damage and mitigate induced ischemia wi th improvement in contractile reserve of the heart as evidenced by contrast echocardiography at rest and under dobutamine stress. TMR is an emerging s urgical strategy for treatment of myocardial ischemia not amenable to conve ntional percutaneous or surgical revascularization. Eleven pigs underwent a meroid occluder placement at the origin of the circumflex coronary artery. Six weeks later, occlusion of the circumflex coronary artery was documented . TMR was then carried out on 10 pigs by using a prototype pulsed CO2 laser that delivered 8-12 joules in 1.5 ms with a spot size of 1 mm. Six weeks a fter TMR, the pigs were restudied. The animals developed significant ischem ia after 6 weeks of ameroid occlusion, at rest (p = 0.01) and at peak stres s (p = 0.004). Wall motion for the ischemic segments improved significantly 6 weeks after TMR at peak stress (p = 0.02). TMR results in an improvement in wall motion in our model of chronic ischemia and improves wall motion s core index more during induced stress than at rest.