CardioExchange Archive

An entirely predictable consequence of medical progress is the growing number of heart patients with persistent and symptomatic angina who have run out of treatment options. A small new study published in the New England Journal of Medicine raises the possibility that a new device one day may provide them some relief. The experimental device, a coronary sinus reducer system, is delivered through a catheter to the coronary sinus, where the device is then expanded with a balloon, blocking flow through most of the vessel except for a small central orifice. Once in place the device causes an increase in coronary sinus pressure that appears to relieve angina, though the authors acknowledge that the “physiological rationale for a beneficial effect… remains unclear.”

Investigators in the Coronary Sinus Reducer for Treatment of Refractory Angina (COSIRA) trial studied 104 patients with CCS class III or IV angina who were not considered suitable candidates for revascularization. Patients were randomized to the device or a sham procedure. Only the team in the cath lab was aware of the treatment assignment.

The device was successfully implanted in 50 out of the 52 patients in the treatment group. The primary endpoint, an improvement of at least two CCS classes at 6 months, was reached in 18 of 52 patients in the treatment group compared with 8 of 52 patients in the control group (35% versus 15%, p=0.02). Mean CCS class went from 3.2 to 2.1 in the treatment group and from 3.1 to 2.6 in the control group (p=0.001).

An improvement of at least one CCS class occurred in 71% of patients in the treatment group versus 42% of the control group. Quality of life, as measured by the Seattle Angina Questionnaire, was also improved more in the treatment group, but there were no significant differences in angina stability or frequency. Exercise duration increased by 59 seconds in the treatment group versus 4 seconds in the control group.

In an accompanying editorial, Christopher Granger and Bernard Gersh write that the study was “well performed and showed significant improvements in reducing angina and improving quality of life.” Its chief limitations are its small size and the possibility that patients or physicians may have become unblinded during the trial. “If confirmed in subsequent trials, coronary-sinus reducing therapy may be a welcome and needed addition to the options to improve the quality of life of patients with refractory angina.”

Commenting on the study, John Spertus said that despite the limitations of the study its results are plausible. “The study design is about as good as can be done for something like this,” he said. He was struck by the “large and impressive” improvement in quality of life.