Laser Heart Therapy Brings Hope to Chest Pain Patients With Few Options
It appears that there are more questions than answers when it comes to PTMR. Timothy Sanborn, MD, professor of medicine at Weill Medical College of Cornell University in New York, says the original theory of transmyocardial revascularization was that "one could increase blood flow by creating these channels." When it was clear that the channels close up, other theories surfaced, he says.
For example, the therapy may promote new blood vessel growth in the heart, improving blood flow. Or it may be that the laser injures nerves in the heart wall, thus blocking the ability of those nerves to send pain signals. "Or it may be a combination of various mechanisms that produce these results," Sanborn says.
Another possibility is that the improvement is caused by the placebo effect. Other studies have demonstrated that giving a placebo such as a sugar pill can produce improvement in symptoms. This same placebo effect has been demonstrated in several other studies, says Sanborn.
Perin tells WebMD that it is unclear why PTMR improves both exercise tolerance and chest pain, which doctors measure by using an angina class scale. Angina class III/IV means severe, disabling disease. "I think it has something to do with these channels, even though we know that the channels do close," he says. "We are not tickling the ventricle; these are real channels. And so I believe the effect is in some way related to these channels."
Hendel says that he, too, "thinks there is really something happening here -- something more than a placebo effect."
Hendel and Kornowski agree. They say that this trial is being followed by a larger study that's being conducted at several medical centers. That study, they say, may provide the final answer to the placebo issue.