Image: The Neovasc hourglass-shaped reducer system (Photo courtesy of Neovasc).
Using a procedure similar to a coronary stent implantation, a novel stent addresses refractory angina (RA) by narrowing the coronary sinus, creating backflow pressure into the heart.
The Neovasc (Richmond, Canada) Neovasc Reducer System is comprised of the Reducer, a stainless steel, hourglass-shaped mesh that is three millimeters in diameter at its smallest point, which is delivered premounted on a proprietary balloon catheter. In a standard percutaneous coronary intervention (PCI) procedure, a catheter is inserted in the patient's groin area, delivering the Reducer inside the coronary sinus; the procedure is usually completed in 20 minutes. Within six to eight weeks, tissue grows over the mesh, narrowing the coronary sinus.
The narrowing creates a resistance backflow pressure, which provides relief of RA symptoms by altering blood flow in the heart's circulatory system, thereby increasing the perfusion of oxygenated blood to ischemic areas of the myocardium. A nonrandomized study involving 15 patients with RA who were treated with the device showed a significant improvement in symptoms, which was maintained at three years of follow-up. Patency of all the devices was documented by means of computed tomographic (CT) angiography, and showed no evidence of device migration.
“Physicians are frustrated by the current lack of options for treating the growing population of refractory angina patients, who can have great difficulty simply walking to the mailbox or going to the bathroom,” said Christopher White, MD, medical director of the John Ochsner Heart & Vascular Institute (New Orleans, LA, USA). “Data shows the Reducer improved angina ratings in a significant proportion of patients. We are also optimistic that its simplicity of implantation and strong safety data will help make the Reducer widely accessible to patients with severe angina.”
Refractory angina currently affects over two million patients worldwide, who typically experience severe chest pain from even minor physical exertion, and as a result lead restricted lives. The incidence of RA is growing, yet these patients have largely exhausted available treatment options. But occlusion of the coronary sinus, the major venous drainage of the left heart, results in preservation of the endocardial to epicardial perfusion ratio and reduction of myocardial infarction size.