Efficacy of coronary sinus reducer implantation in patients with chronic total occlusion of the right coronary artery

Background: Clinical efficacy of coronary sinus reducer (CSR) in refractory angina (RA) patients with ischemia due to the chronic total occlusion (CTO) of the right coronary artery (RCA) remains unknown. Aims: To evaluate the efficacy of CSR implantation in RA patients with CTO RCA and compare them to CSR recipients with left coronary artery (LCA) ischemia. Methods: Consecutive patients with CTO RCA from 2 centers were prospectively included and compared to patients with LCA ischemia. All patients underwent evaluation of angina severity and quality of life (QoL) at baseline and after 12 months. In a subgroup of CTO RCA patients, stress cardiac magnetic resonance (CMR) imaging was also performed. Results: Twenty-two patients with CTO RCA and predominant inferior and/or inferoseptal wall ischemia (the CTO RCA group) were compared to 24 patients with predominant anterior, lateral, and/or anteroseptal wall ischemia (the LCA group). While the Canadian Cardiovascular Society (CCS) angina score mean (SD) improved in the CTO RCA group from 2.73 (0.46) to 1.82 (0.73) (P <0.001) and in the LCA group from 2.67 (0.57) to 1.92 (0.72) (P <0.001), there was no intergroup difference (P = 0.350). Significant improvement in all domains of the Seattle Angina Questionnaire was observed. Stress CMR did not show a significant reduction of ischemic inferior and/or inferoseptal segments, however, improvements in the transmurality index (P = 0.03) and the myocardial perfusion reserve index in segments with inducible ischemia (P = 0.03) were observed in the CTO RCA group. Conclusions: In CTO RCA patients, CSR implantation alleviated angina symptoms and improved QoL. The extent of improvement was comparable to that observed in patients with LCA ischemia.