Myocardial Laser Revascularization

What is Myocardial Laser Revascularization?

In general revascularization is the process of restoring the functionality of an affected organ. Contrast this term with vasculature, which describes the circulatory structures of an organ.

myocardial laser revascularization (MLR) involves a thorough analysis and diagnosis and treatment of the existing diseased vasculature of the affected organ, and can be aided by the use of different imaging modalities such as magnetic resonance imaging, pet scan, CT scan, and X-ray fluoroscopy.

This is a concept important in the subdisciplines of biomedicine which are concerned with the rehabilitation of important organs, such as the heart, liver, and lungs.

The term revascularization is also used in conjunction with other medical terms such as {moslink othermenu:Angioplasty}angioplasty{/moslink}, cardiac, and myocardial to denote specific forms of revascularization techniques.

Treatment for gangrene often requires revascularization, if possible. The surgery is also indicated to repair ischemia (inadequate tissue perfusion) in some forms of chronic wounds, such as diabetic ulcers (Gottrup, 2004).

Myocardial Laser Revascularization: History

From the earlier and obsolete use of mechanical myocardial revascularization using needle puncture and left ventricular biopsy in the 60’s, the use of CO2 laser in the 80’s initially during CABG and subsequently as a stand alone procedure using lateral thoracotomy, to the introduction of percutaneous laser myocardial revascularization in the late 90’s, a recurring theme was noted: All these procedures resulted in a significant improvement in angina class and exercise capacity without any consistent demonstrable improvement in left ventricular function or myocardial blood flow. The concept, Transmyocardial Laser Revascularization, was based on the work of early investigators who were seeking to emulate reptilian circulation in the mammalian heart. A variety of techniques which included needle acupuncture, punch biopsy boring of left ventricular conduits, and insertion of T-Tubes into the left ventricle were attempted. Initial results, in the first one to two months, were promising. The mechanical injury, initiated the sequence of cell infiltration, fibrosis, scarring, and closure of these channels after two months. A study of what was then a new source of energy, the laser, which was developed in the mid 1960’s by Maimon, and an interest in the work of the early investigators led to the initial animal studies that showed that following coronary ligation infarct size was smaller in hearts that were revascularized by laser, mortality was reduced, and channels remained patent (results first presented in 1971). In the early 80’s (1982), one patient, who could not be weaned from cardiopulmonary bypass following coronary artery bypass grafting, was revascularized using the laser and subsequently successfully weaned from bypass. That patient had an uneventful postoperative course, 12 more patients were studied (adjunct to CABG), with "incredible" anecdotal reports.

Myocardial Laser Revascularization: Modern Developments

Development of the clinical high power CO2 laser system, the Heart Laser, for transmyocardial laser revascularization on the beating heart by Laser Engineering, now PLC Medical Systems, led to the first FDA approved clinical trials as a stand alone therapy in the United States.