Chronic intractable angina, also called refractory angina, is a condition characterized by debilitating chest pain, known as angina, despite being on a prescribed medication plan. Patients with refractory angina often respond poorly to invasive procedures such as angioplasty or bypass surgeries. Angina is a recurring pain or discomfort in the chest that occurs when part of the heart muscle does not receive enough blood. When there is a reduction in blood flow to the heart muscle (i.e., ischemia), the body's response is to form tiny new blood vessels to facilitate blood flow around the blockage. This process is called angiogenesis. The process of angiogenesis is turned off for unknown reasons in patients with chronic unstable angina. Therefore, therapeutic angiogenesis is employed to enhance the formation of new vessels in order to re-vascularize ischemic tissues. Therapeutic angiogenesis often involves delivery of growth factors or stem cells. Gene therapy is considered one of the best approaches for treating chronic intractable angina through therapeutic angiogenesis. Gene therapy involves the transference of growth factor genes into the heart to reduce or stop the debilitating chest pain (angina).
With gene therapy, the heart incorporates the genes, allowing sustained release of the angiogenic proteins for weeks. These released proteins or growth factors induce angiogenesis in order to reduce the symptoms of refractory angina for a long duration. Several studies are in the process of exploring more genes for improved treatment of chronic intractable angina.
Baylor Heart Hospital