This review examines the effectiveness and safety of a surgical intervention using a laser device directly on the heart surface for patients suffering from angina for whom other interventions are not suitable. This is an updated version of the original review published in 2009.
Patients with prolonged or recurrent chest pain due to heart disease have different treatment options, such as medication, catheter interventions, or coronary artery surgery. In spite of the optimal use of such treatments, an increasing number of patients progress to advanced disease, becoming less responsive to medical treatment, suffering from more severe symptoms, very limited exercise capacity and poor quality of life. Transmyocardial laser revascularization (TMLR) is a surgical intervention intended to re-establish blood flow in some areas of the heart, using a laser device directly on the heart surface, thereby relieving angina and improving symptoms.
Several studies have been carried out to determine the efficacy and safety of this intervention, but most had important methodological limitations and high risk of performance bias in relation to subjective outcomes such as angina pain. Overall, 43.8% of patients in the group treated with laser had their chest pain improved significantly, compared with 14.8% in the medication group. However, the evaluation of chest pain was performed without blinding (patients and doctors were aware of the intervention) and this may have biased the results. On the other hand, the risk of dying at one year was similar between the groups, but there is an excess risk of early mortality following the intervention in the laser group.
This updated review concludes that there is no evidence of clinical benefits after TMLR, but data on safety suggests that the procedure may pose unacceptable risks. The intervention is becoming obsolete and it is not expected that new research in this field would change this conclusion.
This review shows that risks associated with TMLR outweigh the potential clinical benefits. Subjective outcomes are subject to high risk of bias and no differences were found in survival, but a significant increase in postoperative mortality and other safety outcomes suggests that the procedure may pose unacceptable risks.
This is an update of a review previously published in 2009. Chronic angina and advanced forms of coronary disease are increasingly more frequent. In spite of the improvement in the efficacy of available revascularization treatments, a subgroup of patients continue suffering from refractory angina. Transmyocardial laser revascularization (TMLR) has been proposed to improve the clinical situation of these patients.
To assess the effects (both benefits and harms) of TMLR versus optimal medical treatment in people with refractory angina who are not candidates for percutaneous coronary angioplasty or coronary artery bypass graft, in alleviating angina severity, reducing mortality and improving ejection fraction.
We searched the following resources up to June 2014: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the metaRegister of Controlled Trials database, ClinicalTrials.gov, and the WHO International Clinical Trials Registry. We applied no languages restrictions. We also checked reference lists of relevant papers.
We selected studies if they fulfilled the following criteria: randomized controlled trials (RCTs) of TMLR, by thoracotomy, in patients with Canadian Cardiovascular Society or New York Heart Association angina grade III-IV who were excluded from other revascularization procedures.
Three authors independently extracted data for each trial about the population and interventions compared and assessed the risk of bias of the studies, evaluating randomisation sequence generation, allocation concealment, blinding (of participants, personnel and outcome assessors), incomplete outcome data, selective outcome reporting, and other potential sources of bias.
From a total of 502 references, we retrieved 47 papers for more detailed evaluation. We selected 20 papers, reporting data from seven studies, which included 1137 participants, of which 559 were randomized to TMLR. Participants and professionals were not blinded, which suggests high risk of performance bias. Overall, 43.8% of participants in the treatment group decreased two angina classes, as compared with 14.8% in the control group: odds ratio (OR) 4.63, 95% confidence interval (CI) 3.43 to 6.25), and heterogeneity was present. Mortality by intention-to-treat analysis was similar in both groups at 30 days (4.0% in the TMLR group and 3.5% in the control group), and one year (12.2% in the TMLR group and 11.9% in the control group). However, the 30-day mortality as-treated was 6.8% in the TMLR group and 0.8% in the control group (pooled OR was 3.76, 95% CI 1.63 to 8.66), mainly due to a higher mortality in participants crossing from standard treatment to TMLR. The assessment of subjective outcomes, such as improvement in angina, was affected by a high risk of bias and this may explain the differences found. Other adverse events such as myocardial infarction, arrhythmias or heart failure, were not considered in this review, as they were not predefined outcomes in trials design and they show a high inconsistency across studies. No new trials on transmyocardial laser revascularization have been published in the last ten years and it is very unlikely that new research will be undertaken in this field.