Monday, December 1, 2003

Laser Heart Treatment Not Used As Intended
By Mike Upchurch

An expensive, risky, and controversial treatment for heart disease-related chest pain is frequently given to patients who do not meet the FDA criteria for its use. A DCRI-led study shows that 83% of transmyocardial revascularization (TMR) procedures occur in combination with other cardiac procedures, despite TMR being approved only as a stand-alone treatment.

Dr. Eric Peterson

The study, led by the DCRI’s Dr. Eric Peterson and Dr. Bruce Ferguson of Louisiana State University, was a joint effort by the Society of Thoracic Surgeons and the Centers for Education & Research on Therapeutics (CERTs) program. CERTs is a nationwide research network of private and academic research institutions headquartered at the DCRI. The FDA was the primary sponsor of the study via a grant to the Society.

Using the Society of Thoracic Surgeons (STS) National Cardiac Database, Peterson and his team identified 3717 patients undergoing TMR at 173 hospitals across the country. Through the extensive details in the database, which collects data on two-thirds of all hospitals performing cardiac surgery in the U.S., the investigators gathered information on patient baseline health and the outcomes of their TMR operations.

The controversial laser procedure, which drills holes in a beating heart to improve blood flow and improve severe chest pain, is approved by the FDA only for high-risk patients who cannot undergo angioplasty or bypass surgery.

But this CERTs study found that surgeons are more and more frequently using it in conjunction with those same procedures, particularly bypass surgeries. Just 21% of patients undergoing TMR met the FDA’s strict criteria for its use.

This “off-label” use is common for medications and slightly less so for surgical procedures. TMR’s approval even for its current indication was met with skepticism. Assessing its impact outside that indication, according to Peterson, is difficult.

“No one really knows what happens,” he said.

But this study is helping to shed at least a little light on that dim subject. Peterson and his colleagues found that patients who had had a heart attack in the previous 3 weeks were twice as likely to die undergoing TMR than those who had not. Similarly, patients experiencing unstable or worsening chest pain were at greater risk. These two conditions, previous heart attack and unstable pain, were the very risk factors the FDA warned physicians about when TMR was first approved.

Simply changing the timing of TMR and waiting until patients were more stable, according to Peterson, could effectively halve its risks.

When combined with bypass surgery, TMR did not offer improved survival rates or lower rates of complications, according to the CERTs study results. A much smaller, single-site study of TMR in 2000 suggested it would, but Peterson and his team found otherwise.

This sort of insight would not be possible without the collaboration between the DCRI, CERTs, and the STS, according to Peterson and his co-authors.

“The STS National Database offered a prime opportunity to track use and results of a new technology in the ‘real world’,” they write.

Joining Dr. Peterson from the DCRI were Padma Kaul and Bradley Hammill. Their results were published in the November 5 issue of the Journal of the American College of Cardiology.