Experts Question Use of Laser Therapy for Angina -- Despite Promising Research Results
Lange tells WebMD that two other studies have not produced the positive results of the Texas study, which is why he and others remain cautious about recommending TMR. "What you're looking for in a therapy that's going to be effective is some consistency, and that's the thing we're lacking."
In the second reported study, researchers at 18 U.S. medical centers followed 275 patients with class 4 (the most serious) angina. Those who received TMR saw their angina improve and had lower hospitalization rates, but did not have improved heart function.
While no one denies that TMR improves quality of life for certain patients, Lange tells WebMD that it is imperative to determine precisely how and why. "If it's a placebo effect [a positive response to the fact of taking medication, rather than to the medication itself], then there are other [lower-risk] therapies that can also have a powerful placebo effect," he says.
The researchers and editorialists do agree that all studies to date point to a specific population most likely to benefit from TMR. "If people are going to apply this to anyone," says Lange, "it should be applied only to those without markedly depressed heart function or unstable angina."
Horvath tells WebMD that in his clinical trials, patients with unstable angina have fared best when the procedure was performed "two weeks after their last episode." In patients with chronic, stable angina, the death rate following the procedure is 1%, he adds.
To help settle the TMR debate and move toward formal guidelines, Lange suggests "continued studies with a hard end point, such as improvement in survival, rather than the soft end point of 'How do you feel?'"