Angina occurs when the heart's demand for oxygen-rich blood is not met by the coronary arteries, which are usually clogged with atherosclerotic plaques. In a bypass procedure, veins from the leg are used to redirect oxygen-rich blood around blockages and directly to heart muscle. In angioplasty, a tiny balloon is threaded through the arteries feeding the heart and inflated, clearing plaque blocking the artery. A computer synchronizes the laser pulses with the pumping of the heart, and the blood in the chamber keeps the laser burst from traveling any farther. Depending on the extent of the heart disease, the surgeons create 20 to 40 channels in the moribund heart muscle, and the holes on the heart's surface almost immediately seal themselves with clotted blood and heal over.
Patients typically go home after four days in the hospital.
The study also showed that TMR might not be as effective for those patients whose heart disease has progressed to unstable angina, a severe form of angina that requires emergency hospitalization and treatment in a cardiac care unit. For this reason, TMR should be offered only to patients before their disease progresses to unstable angina. We do know that there is new capillary growth into the new channels. At Duke, we are using animal models to better understand exactly why this occurs. It appears that the new growth is somehow related to the inflammatory response to the creation of the channels.