RecruitingDevice studySelf Expanding Coronary Sinus Reducer for Treatment of Symptomatic Coronary Microvascular Dysfunction (CMD)VahatiCor's Coronary Sinus Reducer (A-FLUX) has been designed to improve angina or angina-like symptoms in patients with CMD. SERRA-I is an early feasibility study that evaluates the safety and clinical performance of the A-FLUX Reducer in this population.