Transmyocardial Revascularization (TMR)

Transmyocardial revascularization (TMR), also known as transmyocardial laser revascularization (TMLR), is a minimally invasive surgical procedure employed for the treatment of patients with severe angina, a symptom of coronary artery disease. Angina is a type of chest pain or chest discomfort that occurs as a result of decreased oxygen-rich blood flow to the heart (ischemia).

Transmyocardial revascularization involves the use of  special carbon dioxide (CO2) lasers  to make tiny channels or pinholes through the heart muscle and into the lower-left chamber of the heart (the left ventricle) to  improve the flow of oxygen-rich blood to the heart muscle, decreasing the occurrence of angina. The left ventricle pumps oxygenated blood to the rest of the body.

Indications

Transmyocardial revascularization is indicated as an alternative treatment for patients with coronary artery disease who are not a candidate for other treatment interventions such as angioplasty and stenting, and coronary artery bypass graft (CABG) surgery due to factors such as risk of procedure failure, ill-health, advanced age, advanced heart disease, and other health conditions.

Preparation

Pre-procedure preparation for transmyocardial revascularization may involve the following steps:

• A thorough history and physical examination
• Routine tests such as blood work and imaging
• Refraining from blood thinners, aspirin, or NSAIDs
• Informing your doctor of any allergies to medications, anesthesia, or latex
• Informing your doctor of any medications or supplements you are taking
• Refraining from solids or liquids at least 8 hours prior to the procedure
• Arranging for someone to drive you home after the procedure
• Signing a consent form after the procedure has been explained

Surgical procedure

The Transmyocardial revascularization procedure takes about 60 to 90 minutes and involves the following steps:

• You will lie on your back on the operating table and anesthesia is administered.
• Once the anesthesia takes effect, a small incision is made on the left side of the chest in between the ribs. The ribs are spread along one side to access the heart.
• Your surgeon then uses a special CO2 laser under computer assisted guidance to create tiny channels in the heart’s left ventricle. About 20 to 40 one-millimeter channels are made, based on the patient’s condition.
• These new channels quickly close on the outside of the heart, but remain open inside and help restore the flow of oxygen-rich blood to the heart muscle.
• The computer-guided laser penetrates the appropriate section of the heart in between heartbeats, which helps to prevent electrical disturbances.
• As the procedure can be performed with the heart continuing to beat, there is no need for a cardiopulmonary bypass machine.
• Studies indicate that TMR works by stimulating the growth of new blood vessels and destroying nerve fibers that cause chest pain.
• Finally, sutures are used to close the incision and a bandage is applied.

Postoperative care

Postoperative care instructions following TMR will involve the following:

• You will be transferred to the recovery room where your nurse will monitor your vital signs, including heart rate and rhythm.
• You will have some pain, soreness, and bruising around the incision site. Medications will be provided as needed to keep you comfortable.
• Instructions on incision site care and bathing will be provided to keep the wound clean and dry while it heals.
• Avoid strenuous activities and lifting weights heavier than 10 pounds for a defined period.
• A supervised cardiac rehabilitation program is advised to assist with your recovery and activity level.
• You are advised to take all your prescribed medications and make a few lifestyle changes such as quitting smoking, exercising regularly, maintaining a healthy weight, and eating a healthy diet.
• You should be able to resume your normal activities in a month’s time; however, return to work may take a couple of months depending on the type of occupation.

Risks and Complications

As with all surgical procedures, transmyocardial revascularization may involve risks and complications including:

• Bleeding
• Scarring
• Infection
• Anesthetic/allergic reaction
• Damage to adjacent tissues
• Blood clots or deep vein thrombosis (DVT)

Summary

For individuals with coronary artery disease who are not eligible for coronary artery bypass surgery, the transmyocardial revascularization procedure is an ideal choice to relieve angina or chest pain. The procedure was developed for patients whose blood vessels cannot be bypassed and whose angina has not been relieved with medications or other treatments. The symptoms of angina and coronary artery disease should improve after transmyocardial revascularization, but it may take at least 3 months or more to notice improvement.