Coronary sinus size and ischemia improvement after reducer implantation; "one size to fit them all?"

Aim Coronary sinus (CS) reducer implantation is associated with symptomatic relief of patients with refractory angina. However, 15% to 30% of the patients do not respond to this treatment. Aim if this study was to evaluate the effect of CS size in the effectiveness of the device. Methods Prior to device implantation and at 4-month resting ventricular function was assessed by stress cardiac magnetic resonance. Ischemia was assessed by the myocardial perfusion reserve index (MPRI). Results Fifteen patients (66 +/- 10 years) underwent successful CS Reducer implantation, with improvements in angina class and exercise tolerance. Patients with a smaller CS size (<5.8 mm) presented a significantly higher percentage increase in MPRI (63 +/- 51 vs 9 +/- 30%, P = .03) and a higher reduction in left ventricle end-diastolic volumes. Conclusions Greater benefits, in terms of ischemia improvement, after CS Reducer implantation were seen in patients with smaller CS sizes, suggesting a potential mechanism underlying the observed rates of reducer non-responsiveness.