Transmyocardial revascularization aggravates myocardial ischemia around the channels in the immediate phase

Abstract

We examined whether transmyocardial revascularization (TMR) relieves myocardial ischemia by increasing regional perfusion via the transmural channels in acute canine experiments. Regional blood flow during transient coronary ligation (2 min) was compared before and 30 min after TMR, and at the third transient ischemia the mid-left ventricle (LV) was cut and immediately frozen along the short axis for the analysis of NADH fluorescence in the regions around the TMR channels. In low-resolution analysis (2-4 g tissue or 2-3 cm(2) area), regional perfusion was not significantly altered after TMR, and NADH fluorescence was observed throughout the ischemic region without significant spatial variation. High-resolution analysis (2.8 mg, 1 mm x 1 mm) revealed that the flow after TMR was lower, and NADH fluorescence was higher in the regions close to the channels (1-2 mm) than in the regions 3-4 mm away from them. Creating TMR channels did not improve the regional perfusion and rather aggravated the local ischemia in the vicinity of the channels in the immediate phase.

Transmyocardial Laser Revascularization

“…We, and others, have demonstrated that with acute sustained myocardial ischemia due to coronary artery ligation, TMR channels do not protect the myocardium against infarction. [6] More recently, [16] investigators compared regional flow during coronary ligation in canine hearts before and half an hour after TMR. This indicates lack of meaningful oxygenated blood flow through the TMR channels.…”