Transmyocardial laser revascularization in patients with diffuse coronary artery disease — early clinical results

Krabatsch, T.; Hemple, B; Hofmeister, J.; Lieback, E.; Hetzer, Roland

doi:10.1016/0967-2109(95)94020-w

Cited by 4 publications

(2 citation statements)

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“…Firstly, this was the channel density used in previous experimental studies [10,14]. Secondly, although various numbers of channels have been drilled in the clinical setting, the few studies describing the channel density reported one channel per square centimetre [5,6,18]. scar.…”

Section: Microscopic Examination Of the Laser Channelsmentioning

confidence: 99%

Transmyocardial laser revascularisation in acutely ischaemic myocardium1

Mueller

Tevaearai

Genton

et al. 1998

European Journal of Cardio-Thoracic Surgery

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Objective: Although recent experience suggests that transmyocardial laser revascularisation (TMLR) relieves angina, its mechanism of action remains undefined. We examined its functional effects and analysed its morphological features in an animal model of acute ischaemia. Methods: A total of 15 pigs were randomised to ligation of left marginal arteries (infarction group, n =5), to TMLR of the left lateral wall using a holmium:yttrium-aluminium garnet (Ho:YAG) laser (laser group, n= 5), and to both (laser-infarction group, n=5). All the animals were sacrificed 1 month after the procedure. Haemodynamics and echocardiography with segmental wall motion score were carried out at both time intervals (scale 0-3: 0, normal; 1, hypokinesia; 2, akinesia; 3, dyskinesia). Histology of the involved area was analysed. Results: Laser group showed no change of the segmental wall motion score of the involved area 30 min after the laser channels were made (score: 0 90). Infarction and laser-infarction groups both showed a persistent and definitive increase of the segmental wall motion score (at 30 min: 1.6 9 0.3 and 2 90, respectively; at 1 month: 1.8 90.2 and 1.8 90.4, respectively). These increases were all statistically significant in comparison with baseline values (PB0.5), however comparison between infarction and laser-infarction groups showed no significant difference. On macroscopic examination of the endocardial surface, no channel was opened. On histology, there were signs of neovascularisation around the channels in the laser group, whereas in the laser-infarction group the channels were embedded in the infarction scar. Conclusions: In this acute pig model, TMLR did not provide improvement of contractility of the ischaemic myocardium. To the degree that the present study pertains to the clinical setting, the results suggest that mechanisms other than blood flow through the channels should be considered, such as a laser-induced triggering of neovascularisation or neural destruction.

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Section: Microscopic Examination Of the Laser Channelsmentioning

confidence: 99%

Transmyocardial laser revascularisation in acutely ischaemic myocardium1

Mueller

Tevaearai

Genton

et al. 1998

European Journal of Cardio-Thoracic Surgery

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“…So konnten etwa drei Viertel der Patienten nach der Laseroperation um zwei CCSAnginaklassen geringer eingestuft werden [6,10]. Auch scheint die ergometrische Belastbarkeit nach der TMLR signifikant h6her zu sein als pr~ioperativ [8]. Wenngleich es auch noch keine groBen randomisierten Studien zur Wirksamkeit der TMLR gibt, so verdichten sich zumindest die Hinweise auf einen signifikanten und dauerhaften Rª des Angina-pectoris-Syndroms bei g|eichzeitig steigender physischer Belastbarkeit.…”

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Histomorphologie nach transmyokardialer Laserrevaskularisation

Krabatsch

Schäper

Tambeur

et al. 1997

Herz

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From 11/1994 to 4/1997 we enrolled 140 patients with diffuse CAD refractory to maximum antianginal therapy who are not candidates for PTCA or CABG for transmyocardial laser revascularisation (TMLR). Of these patients aged 63.5 +/- 15 years, 98 had coronary 3-vessel disease, and the average left ventricular ejection fraction was 44%. Eleven out of these 140 patients died from different reasons (pneumonia, myocardial infarction, septicemia). Seven patients who died between the 1st and 20th postoperative day underwent a postmortem examination with histological analysis of the areas treated by TMLR. On the seven investigated ventricles a total of 220 channels were created. The predominant finding in specimens within five days after TMLR was recently closed channels. Furthermore, a zone of necrosis with an average extension of 500 microns on each side of the channel was evident. Many changes were noticeable in specimens from patients who died two or three weeks after TMLR. Freshly clotted material had been replaced by a granular tissue of variable density. High macrophage and monocyte activity was evident. The extent of this cellular activity could be depicted by staining with a special proliferation marker, such as MiB. On the one hand numerous dividing macrophages were observed, on the other, active fibroblasts indicative for the transformation into scar-like tissue. After staining for type-4-collagen, typical for the basal membrane of capillaries, a large number of stained structures was noticeable in the closed channel lumen. Numerous garlandlike structures became visible under higher magnification. By CD 31 incubation, these structures, were found to be lined with endothelium. Further research will be required to indicate whether the laser channels later are partially or completely open, from where the capillaries are supplied, and whether they even connect to the ventricle lumen. But in conclusion, it seems unlikely, that TMLR follows the mechanism of the amphibian heart.

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Histological Findings After Transmyocardial Laser Revascularization

Krabatsch

Schäper²,

Leder³

et al. 1996

J Cardiac Surgery

112

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In recent time, it has become more and more probable that patients with severe diffuse coronary artery disease, who are not candidates for aortocoronary bypass surgery or percutaneous transluminal coronary angioplasty procedures, can benefit from transmyocardial laser revascularization (TMR). But the underlying principle of TMR still remains unclear. This study reports on a histological analysis of eight patients, in whom a total of 250 channels had been created, who died after TMR. The TMR channels were created by a C02 laser surrounded by a zone of necrosis with an extent of about 500 Fm. In the hearts of patients who died in the early postoperative period (1 to 7 days postoperative), almost all channels were closed by fibrin clots, erythrocytes, and macrophages. There were no obvious connections between the channels and the ventricular cavity. In specimens from patients, who died 2 or more weeks after the procedure, a granular tissue with high macrophage and monocyte activity was observable. Within this tissue, we observed a developing network of capillaries. Otherwise, the tissue filling the channels did not substantially differ from scar tissue. We failed to observe connections between the ventricular cavity and the new capillaries. Whether these vessels within the closed channels have any impact on myocardial perfusion remains unclear, but it seems unlikely that the clinical effects of TMR are based on the principle of the amphibian heart. (J Card Surg 1996;11:326-331) There are patients with coronary artery disease, who despite severe angina and significantly restricted quality of life cannot be treated by percutaneous transluminal coronary angioplasty (PTCA) or aortocoronary bypass operation. This concerns patients with diffuse sclerosis of the coronary arteries, as well as those with very small coronaries (small vessel disease). Currently, these patients were more and more treated by transmyocardial laser revascularization (TMR).During a TMR procedure, the surgeon drills

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Transmyocardial laser revascularization in patients with diffuse coronary artery disease — early clinical results

Cited by 4 publications

References 0 publications

Transmyocardial laser revascularisation in acutely ischaemic myocardium1

Transmyocardial laser revascularisation in acutely ischaemic myocardium1

Histomorphologie nach transmyokardialer Laserrevaskularisation

Histological Findings After Transmyocardial Laser Revascularization

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