Search

Background: CO2 and holmium:yttrium aluminum garnet (YAG) transmyocardial laser revascularization (TMLR) are used to treat patients with refractory angina. A randomized trial to investigate the efficacy and safety of XeCl excimer TMLR was performed., Methods: Thirty patients with refractory angina were randomized in pairs to excimer TMLR or maximal medication. We assessed angina, quality of life (QOL), exercise time, myocardial perfusion, and ventricular wall motion at base line and at 3, 6, and 12 months after TMLR., Results: TMLR patients manifested a significantly better outcome with respect to angina class and quality of life. One TMLR patient died perioperatively versus none in the control group. After TMLR angina decreased from class 3.8 +/- 0.4 at base line to 1.9 +/- 0.9 at 12 months versus 3.9 +/- 0.3 to 3.7 +/- 0.6 in the control group, respectively (p = 0.000001). At 12 months a decrease of greater than or equal to two angina classes was indicated in 11 out of 14 TMLR patients versus none in the control group (p = 0.00001). Improved myocardial perfusion or exercise time was not indicated despite a small decrease in reversible wall motion abnormality score., Conclusions: Excimer TMLR significantly relieves angina and improves QOL without evidence of improved cardiac perfusion or function.

Background and Objectives: To investigate the angiogenic effect of CO2, Ho:YSGG, and XeCl excimer TMLR in a rat model with morphologic characteristics of chronic myocardial ischemia., Study Design/materials and Methods: Two channels (200-320 microm) were created per rat heart. After 14 days, vessel numbers and densities in and around laser scars were assessed., Results: Capillary densities in the laser scars were equal between the three lasers ( approximately 130 vessels/mm2) but much lower than in control areas ( approximately 2,100 vessels/mm2). Vessel densities excluding capillaries were significantly higher in Ho:YSGG and CO2 scars compared to excimer scars, while only Ho:YSGG scars contained significantly more large vessels (diameter > or = 20 microm) than control areas. Only rarely, extension of vascular growth into adjacent myocardium was observed in any of the three groups., Conclusions: These results indicate that the angiogenic response following TMLR is limited to the channel scar and related to the scar size rather than the specific laser type.

Animal models used in transmyocardial laser revascularisation (TMLR) research lack the increased fibrosis observed in patients with chronic myocardial ischaemia. This pathology has also been described in patients with chronic elevated afterload, and therefore we evaluated the spontaneously hypertensive rat (SHR) as a model for TMLR research. We compared (1) the myocardial pathology of SHR with the pathology of three TMLR patients, (2) the reaction to TMLR in SHR and human myocardium using three different lasers, and (3) myocardial hypoxia in SHR myocardium and (healthy) Wistar rat myocardium. SHR and human myocardium both showed increased fibrosis and a similar myocardial reaction to TMLR (comparable morphology of fibrotic TMLR channel scars). More hypoxic cells were observed in SHR than in Wistar control rat myocardium. The similarities between SHR and human chronic ischaemic myocardium make the SHR a suitable model for TMLR research.

In the past 35 years many experimental studies have been performed to investigate the revascularization potential of transmyocardial revascularization and the possible working mechanisms underlying the observed clinical improvement in angina pectoris after this treatment. In this review of the experimental literature, the various methods that have been used to create transmyocardial channels and the most supported hypotheses on the working mechanism (channel patency, angiogenesis and myocardial denervation) are discussed and evaluated.

Background and Objective: We present for the first time histologic findings 3 months after clinical transmyocardial laser revascularization using a XeCl excimer laser., Study Design/materials and Methods: Histology was performed on a patient who died from a noncardiac cause 3 months post-excimer TMLR., Results: In the treated myocardium, no patent channels were found but scars were seen with a linear distribution and in continuity with circumscribed small fibrotic endocardial and epicardial scars. The scars were highly vascularized by new vessels, ranging from small capillaries to large thin walled, and sometimes branching ectatic vessels. Sprouting of vessels into the adjacent myocardium was also observed., Conclusion: These results suggest that angiogenesis might play a role in the clinical improvement after TMLR., (Copyright 2001 Wiley-Liss, Inc.)

We present 2-dimensional echocardiographic images of laser-made channels in the myocardium in an experimental model and in a patient treated with transmyocardial laser revascularization.