Principles of Coronary Sinus Narrowing to Relieve Myocardial Ischemia and Improve Angina.

Effective therapy for patients suffering from refractory angina remains a major unmet need. Chronic angina, which is refractory to medical and interventional therapies, affects patients who are not suitable for revascularization, patients following successful revascularization, and patients with coronary microvascular dysfunction. Coronary sinus (CS) narrowing has been studied as a potential therapy for patients with angina. Pre-clinical and clinical data, including 2 randomized sham-controlled clinical trials and 2 large prospective multi-center registries, have confirmed the safety and effectiveness of CS narrowing in patients with refractory angina due to obstructive coronary artery disease (CAD). Preliminary pathophysiologic studies suggest that CS narrowing may also improve coronary microvascular function and alleviate microvascular angina. Here, we review the historical perspective, mechanism of action, and clinical applications of CS narrowing. In Conclusion: With the accumulation of new data, the time is ripe to revisit the therapeutic benefits seen in historical CS interventions and demonstrated in recent clinical research to reduce angina and ischemia and improve quality of life of patients with disabling refractory angina.