Authors' objectives:

To review the scientific knowledge about the effectiveness and safety of transmyocardial laser revascularization (TMLR), and the legislative frameregarding the application of lasers in TMLR.

Authors' results and conclusions: Nineteen references have been found about experimentation with laser in different laboratory animals and about the perforation of channels (transmural or not) in the myocardial wall (via epicardium or endocardium). There are broad discrepancies in theresults. Clinical experience in humans beings published in the literature is scarce (less than 200 cases), and they are non-controlled studies (clinical report, descriptive studies). All studies coincide in the improvement of symptoms. Generally, improvements in myocardial perfusion are described, although there are studies in which no statistically significant differences are found. TMRL does not seem to improve ventricular function, and there are contradictory results as regards wall motion. There are very few histologic studies about the patency/persistence of the channels, and more recent and in short term studies show opposite results. TMLR seems a lesser risk revascularization procedure. The TMRL register and other clinical series show a 10-12 % mortality during follow-up. A laser device proposed for TMRL (Heart LaserTM) has been recently endorsed with the "CE mark" as regards electrical safety, laser performance, labelling, and instructions for use, but with no mention to clinical effectiveness or safety. The endorsement of the "CE mark" implies the authorization for its free marketing in the European economic space. In the USA the same equipment is currently under IDE with a strict research protocol supervised by the FDA. Experiments with laser in different laboratory animals to create channels in the ventricular wall show contradictory results. Clinical experiences in humans beings are, on the other side, very limited and with great qualitative deficiencies. No randomized controlled trial has been reported so far about TMLR, although some of them have been proposed and are currently under way. All studies report a symptomatic improvements of the patients intervened. However this is a very subjective parameter, and, therefore, very influenceable (placebo effect). Other more objective effectiveness parameters show variable results. In the assessment of TMRL it should be considered, firstly, the need of trials avoiding the bias inherent to observational studies. It should be guaranteed that those studies are sized enough to detect differences, and have a blind assessment of the efficacy measures. One single device (CO2 laser for TMLR) has been differently considered (marketing) in Europe and in the USA. In the former it has been endorsed the "CE mark", which grants its free marketing, and in the USA this is a research device with limited distribution and under a strict research protocol. Prior to its diffusion, any type of health technology should be accurately assessed in terms of efficacy and safety. However, it seems that this technology is rapidly spreading, thanks to the availability of the "CE mark".

Authors' recommendations: The reported limitations should influence its introduction, under strict research protocol, in centres with adequate staff and technical equipment. Assessment of TMLR should address a design avoiding the biases of observational studies, considering the ethical principles of research in human beings, and the current clinical trials regulations. These considerations are applicable to any type of laser proposed for TMLR. The role of the European notify bodies and its capacity to interpret the current regulations should be revised, since, as in this case, the features of the certifications may prevent the creation of the grounds for a rational distribution of new technologies according to criteria of clinical efficacy and safety.

Project Status: Completed

URL for project: http://www.gencat.net/salut/depsan/units/aatrm/html/en/dir393/doc7921.ht ml

Year Published: 1996

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Spain

Organisation Name: Agencia de Qualitat i Avaluacio Sanitries de Catalunya

Contact Address: Antoni Parada, CAHTA, Roc Boronat, 81-95 (2nd floor), 08005 Barcelona, Spain, Tel. +34 935 513 928, Fax: +34 935 517 510

Contact Name: direccio@aatrm.catsalut.net / aparada@aatrm.catsalut.net

Contact Email: direccio@aatrm.catsalut.net / aparada@aatrm.catsalut.net

Copyright: Catalan Agency for Health Technology Assessment and Research