Cardiovascular disease is the leading cause of death and disability in the U.S., according to the American Heart Association (the “AHA”). 
Coronary artery disease is the principal form of cardiovascular disease and is characterized by a progressive narrowing of the coronary arteries, which supply blood to the heart. This narrowing process is usually due to atherosclerosis, the buildup of fatty deposits, or plaque, on the inner lining of the arteries. Coronary artery disease reduces the available supply of oxygenated blood to the heart muscle, potentially resulting in severe chest pain known as angina and damage to the heart. Typically, the condition worsens over time and often leads to heart attack or death. According to the AHA, 1.5 million Americans have heart attacks each year, of which 500,000 die annually.
Based on standards promulgated by the Canadian Heart Association, angina is typically classified into four classes, ranging from Class I, in which anginal pain results only from strenuous exertion, to the most severe class, Class IV, in which the patient is unable to conduct any physical activity without angina and angina may be present even at rest. The AHA estimates that more than 16 million Americans suffer from coronary heart disease and over 9 million experience anginal symptoms, increasing at a rate of 8% per year.55
The primary therapeutic options for treatment of coronary artery disease are drug therapy, percutaneous coronary intervention (PCI) including techniques such as PTCA, stent placement and atherectomy, and coronary artery bypass graft surgery (“CABG” or “open heart bypass surgery”). The objective of each of these approaches is to increase blood flow through the coronary arteries to the heart. Drug therapy may be effective for mild cases of coronary artery disease and angina (e.g., by reducing blood levels of cholesterol). Due to the progressive nature of the disease, however, many patients with angina ultimately undergo either PCI or bypass surgery.
When these treatment options are exhausted, the patient is left with no viable surgical alternative other than, in limited cases, heart transplantation. Without a viable surgical alternative, the patient is generally managed with drug therapy, often with significant lifestyle limitations. Transmyocardial laser revascularization (TMR) offers proven relief to a class of patients with severe cardiovascular disease refractory to other therapies. These patients are characterized by moderately compromised ejection fractions, double and triple vessel coronary artery disease and a history of failed prior interventions, including previous bypass surgery. These patients are refractory to medical therapy and are not candidates for other conventional interventions, and account for up to 12% of CAD patients undergoing diagnostic catheterization.8
Additionally patients who are candidates for CABG procedures, but who will be left incompletely revascularized by CABG alone, may benefit from the adjunctive application of TMR. In a contemporary series of patients undergoing angiography, Williams estimates that 28.8% of patients had significant CAD and did not undergo complete revascularization.53