Author + information
- Francesco Giannini, MD∗ (, )
- Luca Baldetti, MD,
- Neil Ruparelia, MD,
- Francesco Ponticelli, MD and
- Antonio Colombo, MD
- ↵∗Interventional Cardiology Unit, San Raffaele Scientific Institute, Via Olgettina 6020132, Milan, Italy
We read with interest the letter by Dr. Lozano and colleagues regarding our paper (1). Their letter raises the hypothesis of an adjunctive potential role of the coronary sinus (CS) Reducer (Neovasc, Richmond, BC, Canada) for a patient population beyond the scope for which it is currently approved, namely: patients with severe diffuse coronary artery disease (CAD) not amenable for revascularization, regardless of angina status. As the authors state, this patient group represents a significant minority of those presenting to the cardiac catheterization laboratory; however, they currently have limited therapeutic options but an associated high mortality rate (2).
The CS Reducer is currently approved for the treatment of patients with refractory angina who are unsuitable for coronary revascularization procedures. In March 2015, the randomized, double-blind COSIRA (Coronary Sinus Reducer for Treatment of Refractory Angina) trial demonstrated a significant improvement in angina symptoms following Reducer implantation when compared with a sham procedure (3). However, despite a clear need for novel effective therapies to improve symptoms and quality of life in this challenging population, just over 800 implants have been performed in over 3 years.
The low adoption rate is related to 2 main reasons: the absence, in many countries, of reimbursement policies for this procedure, and the concern in the wider interventional community that Reducer implantation may be associated with a large placebo effect that may not result in a persistent long-term benefit. There are also many unanswered questions relating to its exact mechanism of action. Indeed, although Reducer is hypothesized to alleviate symptoms by improving perfusion in ischemic myocardial territories, to date, no study has evaluated its effect upon myocardial perfusion with no clear demonstration of its mechanism of action.
We are currently working on evaluating the impact of CS Reducer implantation upon myocardial ischemia by dipyridamole stress cardiac magnetic resonance in patients with advanced CAD and refractory angina. The study may also provide useful insights with regards to CS Reducer mechanism of action.
The objective demonstration of a reduction in myocardial ischemia following CS Reducer implantation may have several clinical implications. Primarily, it should further support the use of this novel technology in CAD-related refractory angina patients and evidence of inducible myocardial ischemia with the aim of improving angina symptoms and quality of life. Moreover, according to the proposal by Lozano and colleagues, it should prompt CS Reducer therapy evaluation in clinical scenarios characterized by advanced CAD not amenable to further revascularization, with evidence of myocardial ischemia and regardless of angina symptoms. Indeed, other patient populations that may potentially benefit include individuals suffering from ischemic cardiomyopathy related to severe systolic or diastolic dysfunction in spite of optimal medical therapy. In both conditions, when inducible myocardial ischemia is evident despite optimal medical therapy, any tool to reduce the ischemic burden should improve heart failure symptoms, quality of life, and theoretically, survival.
In conclusion, we agree with the proposal to test the CS Reducer in patients with severe diffuse CAD regardless of anginal symptoms in order to improve survival. However, we first need to demonstrate that patients undergoing CS Reducer have inducible myocardial ischemia and that CS Reducer therapy results in reduction of myocardial ischemia burden.
Please note: Dr. Giannini has been a consultant for Neovasc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
- Giannini F.,
- Baldetti L.,
- Ponticelli F.,
- et al.
- Lozano I.,
- Capin E.,
- de la Hera J.M.