Two types of mechanical treatments for ischemic heart disease are being used to improve blood flow (perfusion) to the heart muscle. They include the use of lasers to create new channels for blood flow to the heart, and enhanced external counterpulsation (EECP).  While some patients derive clinical benefit from these procedures, neither modality is specific or optimal for inducing therapeutic angiogenesis.

Transmyocardial revascularization (TMR) is a surgical laser procedure that requires patients to be placed under general anesthesia.  A high-energy laser is employed to drill between 20 and 40 one-millimeter wide channels directly into the disease heart tissue. Angiogenesis then occurs within the heart muscle, driven by processes similar to wound healing.^{2, 3, 4} Symptomatic relief in patients with refractory chest pain (angina) from this procedure is thought to result from inactivation of tiny nerves, as well as from improved blood flow to the heart.
In a controlled clinical trial conducted in patients with untreatable angina and ischemia of the left ventricle significantly more patients who got TMR had improved quality of life, relief of their chest pain, longer survival and fewer hospitalizations than those who received traditional medical therapy.⁵ The long-term effectiveness of TMR was studied in a clinical trial enrolling 212 patients with angina and diffuse coronary artery disease who were not candidates for conventional therapy.⁶ After an average follow-up of 5.7 years, 88% of the TMR patients experienced significant improvement in angina symptoms, while only 44% of patients on medical management improved. Additional studies have also showed improved long-term outcomes for patients receiving TMR.^{7, 8}

Enhanced external counterpulsation (EECP) is a non-invasive method for treating ischemic heart failure. Pressure cuffs are inflated around the patient’s legs to compress the blood vessels in the legs and improve return blood flow to the heart. Experimental studies in dogs have shown that EECP increases capillary density in heart tissue starved of oxygen, and improves blood flow.⁹

A number of medical studies of patients with refractory angina established that EECP could reduce angina and enhance exercise tolerance and quality of life.¹⁰ In a recent study, 1458 patients with moderate to severe angina with no option for further invasive coronary revascularization procedures were evaluated.¹¹ At two years after the start of treatment, 74% of moderate and 70% of severe angina patients had sustained improvement of their angina symptoms and remained free of major adverse cardiovascular events.

Another major study of EECP called PEECH (Prospective Evaluation of Enhanced External Counterpulsation in Congestive Heart Failure). In this study 187 patients with mild-to-moderate symptoms of heart failure were randomized to receive either EECP and drug therapy or drug therapy alone.¹² After three months of treatment, patients who received EECP had significant improvement in heart failure symptoms, compared to the control group. At six months post-treatment, 35% of the EECP-treated group increased their exercise time by at least one minute, compared to 25% of the control group.