Evaluation of Transmyocardial Laser Revascularization by Following Objective Parameters of Perfusion and Ventricular Function1

Abstract

TMLR significantly improves long-term clinical status and treadmill stress tolerance, but appears to have little if any effect upon regional and global function, perfusion, and metabolism.

Transmyocardial Laser Revascularization: A Meta-Analysis and Systematic Review of Controlled Trials

“…[23][24][25][26] Only 3 nonrandomized trials were identified, and each of these compared TMR ϩ CABG versus CABG alone (938,452 patients). [27][28][29] Trials with overlapping or duplicate data were excluded, 30 and one trial of TMR plus sympathectomy was excluded. 31 Figures 1 and 2 outline the trial selection for randomized and nonrandomized trials, respectively.…”

“…It has been previously demonstrated that TMR may increase the risk of postoperative heart failure, and the purported mechanism includes inflammatory reaction, edema, or reversible myocardial injury. 29,32 Regardless of the mechanism, the potential for TMR-induced heart failure remains a concern that should be studied further so that the risk-benefit ratio of TMR can be better delineated. Overall, the results at this time suggest that there may be a small increase in risk of decreased left ventricular function within the first year.…”

“…The reasons for the observed heterogeneity in perfusion remains unknown and is consistent with the variation in observations in previous nonrandomized clinical investigations, some of which report demonstrable increased perfusion in ischemic myocardium after TMR and others of which report no change. 29 One randomized trial and one nonrandomized trial of adjunctive TMR evaluated perfusion, and both found no difference. 26,29 Considered in aggregate, the results of this systematic review and meta-analysis contribute little to our understanding of the mechanism of action for TMR and its impact on perfusion.…”

Pathomorphological and Histological Analysis of the Indirect Revascularization Method

“…Despite the fact that TMLR significantly increases myocardial water content in experimental healthy myocardium on a short term basis [23], TMLR is clinically performed mainly in areas of hypo-to akinesia because of the underlying chronic ischemia in viable myocardium [24]. Nevertheless, even in this degenerated myocardium TMLR might cause significant increases in myocardial water content indicating myocardial damage paralleled by a deterioration of myocardial contractility [1,7,8,13,23].…”

Digital Radiographic Quantification of Myocardial Blood Flow Around a Transmyocardial Laser Channel in Rabbit Hearts

“…Although histological, immunohistochemical and molecular studies in animal models have demonstrated the presence of angiogenesis in the myocardium surrounding the treated region, [3][4][5][6][7] the controversy continues as to whether or not TMLR can enhance myocardial perfusion in clinical settings. [8][9][10][11] Various modalities have been employed to assess myocardial perfusion in the TMLR-treated heart such as the microsphere technique, 3,5 positron emission tomography and Tc-sestamibi scintigraphy. [12][13][14] However, perfusion around an individual laser channel has not been analyzed because the required spatial resolution cannot be achieved through these methods.…”