Angiogenesis three months after clinical transmyocardial laser revascularization using an excimer laser

Abstract

These results suggest that angiogenesis might play a role in the clinical improvement after TMLR.

Evaluation of myocardial perfusion and left ventricular function six months after percutaneous transmyocardial laser revascularization: Comparison of two Ho‐YAG laser systems with the same wavelength, but different energy delivery and navigation systems

“…The mechanisms of the significant improvement in the electrical activity consistent with an increased tracer uptake at redistribution in the present study, remain unclear; they probably involve the concepts of stunned and hibernating myocardium in the event of significant coronary stenosis with repetitive ischemic episodes [26]. This might indicate a recovery of the hibernating or stunned cells to a more functional state in the surrounding areas of the revascularized scars of the laser channels [12], even if the neovascularization is unable either to supply sufficient blood flow to compensate the epicardial coronary artery occlusion [12] or to improve the regional function. Neovascularization in the zone surrounding the channels is believed to be induced by an increase in local growth factor production following laser irradiation [12].…”

“…This might indicate a recovery of the hibernating or stunned cells to a more functional state in the surrounding areas of the revascularized scars of the laser channels [12], even if the neovascularization is unable either to supply sufficient blood flow to compensate the epicardial coronary artery occlusion [12] or to improve the regional function. Neovascularization in the zone surrounding the channels is believed to be induced by an increase in local growth factor production following laser irradiation [12]. The uncoupling between increased electrical activity and unchanged regional ventricular function confirms that the functional recovery requires a higher perfusion threshold than achieved by PTMR-induced neovascularization.…”

“…As concerns the mechanism of TMLR, that is, direct blood flow through the laser channels [1,5], conflicting data have been published [6][7][8][9]. However, the clinical improvements observed after TMLR were not negligible; thus, other mechanisms were suggested, such as myocardial denervation through small local infarcts caused by laser injury, the prevention of left ventricular remodeling of the chronic ischemic area, and laser-triggered neoangiogenesis [10][11][12].…”

The vascular response induced by transmyocardial laser revascularization is determined by the size of the channel scar: Results of CO2, holmium and excimer lasers

“…In the past years, extensive experimental TMLR research has been performed [8]. However, none of the used animal models displays the increased myocardial fibrosis which is observed in the chronic ischemic myocardium of the average TMLR patient [9]. In the study presented, we compared the angiogenic response after CO 2 , Ho:YSGG (wavelength 2.09 mm, similar to the 2.12 mm of the clinically used Ho:YAG) and XeCl excimer laser TMLR in a different animal model, the spontaneously hypertensive rat (SHR), that does display increased myocardial fibrosis.…”

Measurement of Myocardial Oxygen Tension: A Valid and Sensitive Method in the Investigation of Transmyocardial Laser Revascularization in an Acute Ischemia Model

“…farction as well as after transmyocardial laser revascularization. Neoangiogenesis in the ischemic heart is supposed to be responsible for the clinical improvement [16][17][18]. In contrast to the positive clinical effects of TMLR, methods such as myocardial scintigraphy, stress-echocardiography, and, partly, magnetic resonance imaging did not show a significant improvement of regional myocardial perfusion in many experimental studies.…”