Coronary Sinus Reduction: New Analysis Suggests Modest Benefits for Refractory Angina
A novel approach to treating severe chest pain – coronary sinus reduction (CSR) using an hourglass-shaped stent – is facing renewed scrutiny. While initial studies hinted at significant relief for patients with refractory angina (chest pain that doesn’t respond to conventional treatments), a new meta-analysis published in JACC: Cardiovascular Interventions suggests the benefits may be less substantial than previously thought.
The analysis, led by Dr. rasha Al-Lamee of Imperial College London,pooled data from three randomized controlled trials encompassing 180 patients,alongside 13 single-arm studies involving 668 individuals. The procedure itself appears safe, boasting a 98.3% success rate. However, a key finding reveals a stark contrast between the results of rigorously controlled trials and earlier, less controlled studies.
Patients did report improvements in angina symptoms in both types of studies. however,the magnitude of improvement was considerably smaller in the randomized controlled trials. Specifically, approximately 26% of patients in the controlled trials experienced at least a one-class improvement in angina severity (according to the Canadian Cardiovascular Society classification), while 17% saw at least a two-class improvement. These figures represent roughly a third of the gains observed in the single-arm studies.
Crucially, the controlled trials failed to demonstrate any objective benefits. Continuous measurements like the Seattle Angina questionnaire showed no significant change, and there was no evidence of improved blood flow to the heart muscle following the procedure.
Dr. Deepak Bhatt, a cardiologist at Mount Sinai in New York City, who penned an accompanying editorial, emphasized the need for more effective treatments for refractory angina patients, who have often fatigued all other options. While CSR holds potential, he cautioned that larger, more definitive trials are essential before widespread adoption. “We need robust,objectively measured evidence to justify the cost of this procedure,” he stated. He pointed to past examples, like percutaneous laser therapy, which initially appeared promising but ultimately proved ineffective in rigorous trials.
Currently approved for use in the UK and Europe, where its adoption is growing, the CSR device is not yet available in the United States. The ongoing COSIRA-II trial, enrolling approximately 380 patients, is expected to provide the conclusive data needed for potential US approval.
Dr. Al-Lamee believes that if COSIRA-II demonstrates clear benefits, the device coudl become a preferred treatment option before more invasive procedures like repeat coronary artery bypass surgery. “Why resort to a high-risk revascularization if a safe and effective option exists?” she proposed.
Dr. Al-Lamee disclosed financial ties to Shockwave Medical, the manufacturer of the CSR device. Dr. Bhatt reported no relevant financial conflicts.