Laser Technique Improves Quality Of Life In Severe Angina

An invasive surgical technique using lasers can improve the quality of life in patients with coronary artery disease in whom bypass surgery or angioplasty is not possible.

A randomised trial in 12 American and one British center used percutaneous transmyocardial laser revascularisation (PTMR), a catheter-based therapy for refractory angina pectoris.

Researchers, led by Dr. Stephen Oesterle, Division of Cardiology, Massachusetts General Hospital, United States, enrolled 221 patients with reversible ischaemia of Canadian Cardiovascular Society angina class III (61 per cent ) or IV (39 percent) and incomplete response to other therapies.

In the trial 110 patients were randomly assigned to PTMR with a holmium:YAG laser, plus continued medical treatment, and 111 were assigned continued medical treatment only. Primary end point was exercise tolerance at 12 months.

Overall, 11 patients died and 19 withdrew, which left 92 patients in the PTMR-group and 99 in the medical-treatment-group who completed the study. Exercise tolerance at 12 months had increased by a median of 89.0 s among the PTMR patients compared with 12.5 s among the medical treatment-only patients.

Researchers point out that diffuse coronary disease limits surgical and angioplasty options for many patients with severe angina. Transmyocardial laser revascularisation (TMR) was recently approved as a palliative procedure by the US Food and Drug Administration. Hand-held laser probes are used via thoracotomy to create multiple transmyocardial channels in areas of ischaemia. The surgical TMR procedure has been adapted to a less invasive catheter-based approach — PTMR.

Researchers conclude that “A limitation of this study is that the randomised treatment allocation could not be concealed from patients or investigators. Investigator bias was detected and accounted for by comparison of masked and unmasked angina assessment. We cannot, however, exclude bias in the participants.

“Although there is controversy as to the mechanisms of action, and the contribution of the placebo effect cannot be quantified, the results of this study suggest that this palliative procedure provides clinical benefits in the defined population of patients.”

Dr. Oesterle comments that their study “lends some credibility to the thought that these laser procedures may relieve angina for individuals with severe diffuse coronary disease. However, we need to recognise the significant potential for placebo effect in these desperately ill patients.”