Transmyocardial Laser Revascularization

  Can you respond to who currently is performing this procedure, indications for treatment and if it is an approved treatment option.

[CCF Cardio MD - MTR]

Dear Heart RN: thank you for your question.  Transmyocardial laser revascularization (TMR)
has been developed as a therapeutic option for patients with severe coronary artery
disease who are not candidates for revascularization procedures (angioplasty or bypass
surgery) yet who still have incapacitating angina.  Currently, TMR can be performed by
cardiac surgeons in the OR or by interventional cardiologists in the cath lab (it is
called percutaneous TMR or PMR in that instance).
  When the coronary arteries are severely diseased yet are too small or are technically
too difficult to revascularize, medical therapy used to be the only option to relieve
angina.  However, as you may know, many patients fail medical therapy.  Pioneering
research has identified angiogenesis (the growth of new blood vessels) as a potential
scientific alternative to medical treatment of severe coronary disease.  Certain growth
factors (the most common being VEGF) stimulate the growth of new, small blood vessels
and are being tested in humans now to improve blood flow to the heart.  However, how to
deliver VEGF to the site where it's needed has proven difficult.  TMR was first developed
by surgeons as an alternative approach.  In TMR, the chest wall is opened and the surface
of the heart is exposed.  Targeting areas of ischemia previously identified by stress
imaging studies, a surgeon uses a high-frequency laser to open tiny holes in the
myocardial tissue to bring blood in from the left ventricular cavity to the heart muscle.
Normally, blood flows in the coronary arteries which lie on the outside surface of the heart
and percolates from the "outside in" to the heart muscle.  With TMR, holes are opened to
direct blood from the "inside out" - that is from the left ventricular cavity to the
heart muscle directly.  These tiny channels are only microns in diameter and do not
transverse the entire thickness of the muscle wall.  With PMR, the same procedure is done
by cardiologists with a catheter inside the left ventricle and the laser beam is fired
from the "inside out" but the intended effect is the same as with TMR.  The goal is to
establish tiny conduits through which blood from the left ventricular cavity can supply oxygen and
nutrients to the nearby starved heart muscle.  Preliminary trials of TMR showed that it relieved angina in comparison to
maximum medical treatment while recent results suggest a mortality benefit from combined
bypass surgery and TMR (for areas unable to be bypassed).  PMR is still being evaluated.
  Let me emphasize however, that TMR and PMR should only be considered experimental
at this time and are available only at tertiary medical centers like Cleveland Clinic
that are involved in ongoing clinical trials evaluating these therapies.  Patients who
would be potential candidates for TMR/PMR include those who have debilitating angina and
who are not candidates for CABG or angioplasty and who have not had extensive scarring of
the ventricle from prior heart attacks. A combined approach of CABG and TMR is also now
being evaluated and is being compared to CABG alone. If you know of a patient who would be
a potential candidate, please call Cleveland Clinic at 1-800-CCF-CARE and ask to speak
with Dr. Steven Ellis or Dr. Patrick Whitlow.
  I hope you find this information useful.  I couldn't find a specific reference to point
you toward but there should be more information in the cardiology literature in the next
year.
Information provided in the heart forum is for general purposes only.  Specific diagnoses
and therapies can only be provided by your physician.