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Transmyocardial Laser Revascularization Fails to Improve Angina

Patients with severe angina due to chronic total occlusion were no better off with percutaneous TMR than with maximal medical therapy.

Transmyocardial revascularization (TMR) with a percutaneous laser catheter has been shown to improve anginal symptoms in unblinded trials, despite lack of a clear scientific basis for expecting benefit in experimental studies. To resolve this apparent contradiction, investigators conducted a prospective, single-blind, randomized trial supported by the manufacturer of a percutaneous holmium/yttrium aluminum garnet (YAG) laser.

Subjects (all with severe angina) underwent planned PCI for chronic total native artery occlusion that subtended viable myocardium; 141 patients in whom PCI was unsuccessful were randomized to TMR with the holmium/YAG laser or to maximal medical therapy (MMT). Although physician-investigators were not blinded to treatment, patients, their families, and treating physicians all were unaware of random assignments. A questionnaire administered to patients before discharge showed that most could not ascertain whether or not they had received TMR.

In-hospital adverse events tended to be more frequent in TMR than MMT patients; 6-month rates were similar in the 2 groups. Angina class improved similarly in both groups by 6 months, as did exercise duration (by 86 seconds after TMR, by 69 seconds after MMT; P=0.73).

Comment: In this single-blind, randomized trial, percutaneous TMR had no benefit over medical therapy in patients with severe angina due to chronic total occlusion. These results contradict those from previous unblinded trials, thereby suggesting an important placebo effect in this study (though across-trial differences might be due to variation in patient populations or revascularization methodology). Nonetheless, these negative findings, coupled with those from unpublished randomized trials, should cause physicians to limit severely the use of percutaneous TMR.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology July 12, 2002

Citation(s):

Stone GW et al. A prospective, multicenter, randomized trial of percutaneous transmyocardial laser revascularization in patients with nonrecanalizable chronic total occlusions. J Am Coll Cardiol 2002 May 15; 39:1581-7.

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