CORRESPONDENCE: LETTER TO THE EDITOR
Percutaneous Laser Revascularization Does Not Equal Transmyocardial Laser Revascularization
Keith A. Horvath, MD*
* Cardiothoracic Surgery Research Program, National Institutes of Health, NHLBI, 10 Center Drive—MSC 1454, Bethesda, Maryland 20892 (Email: khorvath{at}nih.gov).
The recent results of a trial of percutaneous laser revascularization (PMR) (1) are noteworthy for their confirmation that this technique does not appear valid; however, these findings cannot be extrapolated to other forms of laser therapy. Although Leon et al. (1) are to be congratulated for performing this study, they have also peformed a significant disservice by equating results from a 3- or 4-mm subendocardial laser divot placed under remote control using an unapproved laser device with results documented in thousands of patients with a Federal Drug Administration-approved laser in which channels are placed under direct vision and treat the full thickness of the myocardium as is performed with surgical transmyocardial laser revascularization (TMR). The researchers dismissed the TMR results as being largely placebo because their results with PMR were equivalent with a placebo group. Whereas the placebo effect plays a role in any treatment, to dismiss objective data, including improved perfusion as noted by single-photon emission computed tomography (SPECT) and positron emission tomography (PET) scanning, and improved function as noted by echocardiography and magnetic resonance imaging (MRI) (seen with TMR), is wrong. Such improvements cannot be willed by the patient regardless of the strength of the placebo. The symptomatic benefits seen with TMR have lasted longer in more patients than has ever been seen from any placebo.
Furthermore, to equate surgical TMR with internal mammary artery ligation is unfair at best. In addition to severe angina, all of the TMR patients had angiographic evidence and objective demonstration of malperfusion. It is not known whether the patients who underwent mammary artery ligation even had coronary artery disease.
The primary conclusion that can be drawn from this study is that PMR does not work. To extrapolate that to other laser techniques is akin to stating that, like calcium channel blockers, beta-blockers are ineffectual after a myocardial infarction because both are "blockers."
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References
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- Leon MB, Kornowski R, Downey WE, et al. A blinded, randomized, placebo-controlled trial of percutaneous laser myocardial revascularization to improve angina symptoms in patients with severe coronary disease J Am Coll Cardiol 2005;46:1812-1819.[Abstract/Free Full Text]
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