Transmyocardial laser revascularization: histopathological findings

Transmyocardial laser revascularization (TMLR) is a new surgical technique clinically tested in patients with advanced severe coronary arteriosclerosis when classic routine treatment by medicaments, percutaneous transluminal coronary angioplasty (PTCA), or aorto-coronary bypass surgery does not improve symptoms of ischemic heart disease. During the procedure high-energy CO 2 laser performs 35-40 transmyocardial channels via left-sided thoracotomy. Channels are drilled from the epicardial side of the heart through the myocardium into the left ventricle cavity. Impulses are synchronized with EKG (diastole), the channel diameter is about 1 mm. Transmural laser penetration is confirmed by intraoperative transesophageal echocardiography (TEE). This technique is based on a theory that channels allow blood supply from left ventricle directly into the intramyocardial vessels (possibly capillaries) and so improve oxygenation of ischemic myocardium. Presented are gross and microscopic findings in a 75-year-old woman who suffered from classic class IV angina with shortness of breath. She had a history of an inferior myocardial infarct, ventricular tachyarrhythmia, aorto-coronary bypass, and mitral valvuloplasty. Her ejection fraction by echocardiography was 25%. Angiographically, she had multiple occlusions of native coronary arteries and diffuse distal stenosis in the graft of the left internal mammary artery (LIMA) to the left anterior descending coronary artery (LAD). Thirty six of forty laser pulses were confirmed by TEE as transmural. The patient died suddenly of ventricular fibrillation 5 days after TMLR surgery. The autopsy was performed 6 hours after death. After cross-sectioning of the heart all the laser-bored channels were found partially or completely filled by fibrin and cell infiltrate composed mainly of polymorphonuclear leukocytes. Patent channels were found within myocardial scars, channels performed through viable myocardium appeared to be partially collapsed and occluded.