While the heart pumps blood to the entire body, it cannot function without its own blood supply. This blood comes through coronary arteries that surround the heart and penetrate into the heart muscle from the outside. In coronary artery disease, these arteries become stuff, constricted, and narrow. This blocks a good deal of blood flow and causes chest pain (angina). In many cases this blockage is treated with angioplasty, coronary stent placement, or even coronary artery bypass graft (CABG) surgery. However, in some cases these interventions are not possible. That is where transmyocardial laser revascularization becomes a major treatment for angina.
Transmyocardial laser revascularization uses a carbon dioxide laser to cut small channels, about the width of a straight pin, through the entire heart muscle. The surgical approach is surprisingly simple-it takes about two hours. The patient is placed under general anesthesia and an incision is made in the left chest. A laser is then moved to the heart and holes are essentially “burned” from the outside to the inside of the heart. Twenty to forty holes are cut in the heart during transmyocardial laser revascularization.
The holes made during transmyocardial laser revascularization close on the outside surface of the heart but the inside sections remains open. This means that blood can penetrate into the heart tissue from the inside of the heart rather than relying on the diseased coronary arteries alone.
The squeeze of the systolic phase of a heartbeat is forces blood out of the coronary arteries but with transmyocardial laser revascularization, the laser-cut channels actually fill up with blood during the major squeeze of the heart.
The reasons that transmyocardial laser revascularization is an effective treatment for angina are two: the channels permit blood flow and oxygen to the heart muscle and the laser stimulates the growth of new capillaries in heart tissue. The capillaries or thin blood vessels improve blood flow to an oxygen starved heart.
While transmyocardial laser revascularization is a relatively new procedure, there have been enough clinical trials to support it widespread use in properly selected patients. These patients are usually those seeking treatment for angina but have failed to receive full benefit from medical interventions and angioplasty. Heart function improves after transmyocardial laser revascularization and patients report fewer cardiac chest pain symptoms. Also, patients undergoing the procedure report a higher tolerance for exercise and more cardiovascular reserve.
There is some evidence that transmyocardial laser revascularization achieves even better results when combined with coronary artery bypass graft (CABG) surgery. In fact, these two procedures are being performed at the same time. The advantage of this “hybrid” approach is that it provides better symptom relief and possibly long term benefit. Perhaps more importantly the combined surgery means that the patient only has to endure and recover from a single open heart surgery procedure.
Transmyocardial laser revascularization may not be available at all hospitals. It is generally only available at institutions that perform coronary artery bypass graft (CABG) surgery and, even then, not all heart surgeons currently perform transmyocardial laser revascularization.