In certain situations, ischemic coronary artery disease can be present and disabling, but the more conventional treatments are unable to be performed. These people have persistent angina that does not respond to treatment with medication. Because of unfavorable coronary artery anatomy, or severe, diffuse arterial disease, they are not candidates for balloon dilatation, stenting of the coronary artery, or coronary artery bypass. If there is adequate functioning heart muscle present, the disabling angina can frequently be relieved or reduced by using TMR.

Developed in the early 1990's, TMR is a technique whereby channels are created in the ischemic heart muscle using a high energy laser beam. At. St. Thomas Hospital, an holmiun: YAG laser is utilized. The operation is usually performed through a small left chest incision and does not require use of the heart-lung machine. However, it may also be combined with the standard coronary artery bypass operation through a single incision. This procedure has been available at St. Thomas Hospital since 1996. With minimal risk, TMR has afforded good long-term relief of angina pain in the majority of patients on which it has been utilized.