Transmyocardial laser revascularization (TMR) is a procedure used to treat inoperable heart disease in people with persistent angina that is not relieved by any other

revascularization In medical and surgical therapy, revascularization is the restoration of perfusion to a body part or organ that has had ischemia. It is typically accomplished by surgical means. Vascular bypass and angioplasty are the two primary means of rev ...

method. Most people with coronary artery disease are treated with

angioplasty Angioplasty, is also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atheroscle ...

and stenting or coronary bypass surgery and medications to improve blood flow to the heart muscle. The objective of each of these approaches is to increase

blood flow Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously m ...

through the

coronary arteries The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ o ...

to the heart. When these treatment options are exhausted, the patient is left with no viable surgical alternative other than, in limited cases,

heart transplantation A heart transplant, or a cardiac transplant, is a surgical transplant procedure performed on patients with end-stage heart failure or severe coronary artery disease when other medical or surgical treatments have failed. , the most common procedu ...

. Without a viable surgical alternative, the patient is generally managed with drug therapy, often with significant lifestyle limitations. TMR, or transmyocardial laser revascularization, is a newer treatment aimed at improving blood flow to areas of the heart that were not treated by angioplasty or surgery.

Procedures

TMR is a surgical procedure. It is performed through a small incision in the left side of the chest. Frequently, it is performed along with coronary bypass surgery, occasionally alone. When performing TMR a qualified cardiac surgeon delivers a precise laser therapy (either with a Holmium:YAG

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fi ...

or CO₂), directly to the target area(s) of the heart muscle. When performed as a primary therapy, it is done through a small incision between the ribs (

thoracotomy A thoracotomy is a surgical procedure to gain access into the pleural space of the chest. It is performed by surgeons (emergency physicians or paramedics under certain circumstances) to gain access to the thoracic organs, most commonly the hea ...

) with the patient under

general anesthesia General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...

. Transmyocardial laser revascularization (TMR) can also be performed as a secondary procedure in patients that have ischemic heart disease with areas of the heart that cannot be bypassed. The precise laser therapy is delivered to create small channels into the heart chamber. During a typical procedure, approximately 10 –50 channels are made in each targeted region of the

heart muscle Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that ...

. The channels in the heart muscle seal over almost immediately with little blood loss while the new channels allow fresh blood to perfuse the heart wall immediately.The Heart Laser uses a computer to direct laser beams to the appropriate area of the heart in between heartbeats, when the ventricle is filled with blood and the heart is relatively still.

TMR demand

TMR is a treatment option for patients who: * Have severe chest pain ( angina), which limits the patient's daily activities or causes the patient to wake from pain at night, despite medications * Have pre-operative tests that show ischemia * Have a history of previous bypass surgery or angioplasty, and no further intervention is available. * Have been told by their doctor that there is nothing that can be further done to help their symptoms. TMR has shown positive clinical benefits for patients who may require one or two bypass grafts, yet also have other areas of the heart that are not able to be bypassed by direct bypass-surgery. This is often seen in patients with

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

. The surgeon will bypass the targeted blockages and use the Heart Laser on the heart muscle with diffuse disease to achieve more complete blood flow to the heart. TMR is not suitable for patients whose: * Heart muscle is severely damaged due to

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...

s; the heart muscle is dead or scarred rather than affected by inadequate blood supply (ischemic) * Heart muscle has no areas of ischemia

References

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External links

Emedicine: Transmyocardial Laser Revascularization
Cardiac procedures