[The coronary sinus reducer stent for the treatment of chronic refractory angina pectoris].

We were very interested to read the article dealing with therapeutic options in patients with chronic refractory angina pectoris (RAP) signed by Cohen et al. 1 The authors presented an excellent review of the therapeutic options for such ''no-option'' patients suffering from chronic RAP caused by severe symptomatic and chronic coronary artery disease. May we quote Dr. Cohen and colleagues: ''Refractory angina is a major clinical challenge in contemporary cardiovascular medicine. .. Management strategies aimed at improving quality of life are fundamental in the management of these patients and may also be associated with a survival benefit.'' Dr. Cohen and colleagues are right, since chronic refractory angina pectoris has high social impact, making this a socio-medical issue that cannot be left without appropriate solution. Dr. Cohen and colleagues discussed five invasive anti-anginal therapies for chronic RAP: spinal cord stimulation, percutaneous myocardial laser revascularization, transmyocardial laser revas-cularization, autologous CD34+ stem cells, and intramyocardial bone marrow stem cells injection; however, a very important, evolving innovation is missing: coronary sinus intervention. We would ask for the opportunity to provide the readers with supplemental information about the Neovasc coronary sinus reducer stent (CSRS) for the treatment of chronic RAP. Coronary sinus intervention for the treatment of ischemic heart disease is an evolving innovation for patients with chronic angina who are not candidates for coronary artery revascularization. In the mid-1990 s we developed the upside-down strategy to support ischemic myocardium. This means: (1) catheterization of the coronary venous system instead of catheterization of the coronary arteries and (2) reduction of the effective cross area in the coronary sinus instead of expanding a narrowed coronary artery. Our initial studies in pig models proved that either acute permanent occlusion or constriction of the coronary sinus causes epicardial and intramyo-cardial neovascularization. This observation could be seen even at the macroscopic level. After a few years of development we came out with the first percutaneous intravenous CSRS and gave it the name ''Neovasc'', later known as Neovasc Medical, Inc. The CSRS is a balloon-expandable stent, implanted by percutaneous transvenous approach through the right internal jugular vein or any other large peripheral vein. It has a unique shape that reduces the coronary sinus diameter to 3 mm; therefore, instead of increasing the coronary circulation input it reduces its output. The first human study began in 2004. 2 This was a prospective, open-label, safety feasibility study. The CSRS was implanted in …