RESUMO
A sizable portion of patients with angina pectoris secondary to underlying coronary artery disease [CAD] can be effectively treated. Anti-anginal medication has proven efficacious in most patients, and percutaneous coronary revascularization or coronary artery bypass grafting can successfully treat the rest. Low-level laser therapy [LLLT] via its direct, heat-independent effect on the process of tissue repair may play a significant role in the treatment of patients with advanced CAD. We aimed at assessing the safety and efficacy of LLLT in advanced multi-vessel CAD patients not suitable for myocardial revascularization. We evaluated various clinical parameters as well as the results of laboratory tests to seek the indices of the potential impact of laser therapy on the study population. Twenty-two patients [mean age, 61 years old and male gender, 68.1%] with advanced CAD and a history of myocardial infarction underwent two series of irradiation therapy, each series comprising 10 sessions of LLLT and conducted with a three-month interval. In each series, LLLT was administered every other day for 20 minutes per session [excluding one session that lasted only 10 minutes]. The pre-laser evaluation consisted of blood pressure, heart rate, basic biochemical test, electrocardiogram [ECG], six-minute walk test, transthoracic echocardiography, and ECG-gated single photon emission computed tomography [SPECT] perfusion imaging. Three months later, the pre-laser evaluation was repeated. No side effects associated with laser biostimulation or performed clinical tests were noted. An improvement in functional class, and distance covered in the six-minute walk test and decrease in systolic blood pressure was observed. There was also a significant change in the myocardial perfusion of most anterior segments of the heart according to SPECT [visually and by computer software, P<0.05]. There was no significant change in diastolic blood pressure, heart rate, left ventricular ejection fraction by transthoracic echocardiography, and ECG gated SPECT. LLLT resulted in an improvement in functional capacity and myocardial perfusion as well as a reduction in the frequency of angina symptoms during the six-minute walk test. There were no significant changes, however, in the left ventricular function according to transthoracic echocardiography and ECG-gated SPECT. In the short term, LLLT proved to be a safe method. These encouraging results should be confirmed by larger, placebo-controlled studies