Lower Silesia Sinus Reducer Registry is a , single-center, single-arm registry including patients with chronic disabling refractory angina pectoris (Canadian Cardiovascular Society [CCS] classes 2-4) despite maximally tolerated anti-angina medical therapy who underwent Coronary Sinus Reducer implantation .

Lower Silesia Sinus Reducer Registry is a single-center, single-arm registry including all consecutive patients who were referred to the Cardiac Department of Copper Health Center due to chronic disabling refractory angina pectoris (Canadian Cardiovascular Society [CCS] classes 2-4) despite maximally tolerated anti-angina medical therapy and underwent Coronary Sinus Reducer implantation. All patients were evaluated by the local Heart Team and considered not amenable to percutaneous or surgical revascularization procedures. After the Heart Team evaluation patients were qualified for the procedure or Coronary Sinus Reducer implantation unless they met one of the exclusion criteria.

Initial patient evaluation (prior to device implantation) consisted of past medical history, actual clinical assessment with an evaluation of CCS class, Seattle Angina Questionnaire - 7 items (SAQ-7) scores, 6-min walk distance (6-MWT) test, and echocardiography. First, a follow-up visit was scheduled 1 month after the implantation procedure.The study will include clinical assessments every six months during an observation period. The primary outcomes will be gathered one year after the implantation of the CS. Nevertheless, clinical follow-up will continue for up to five years after the procedure.

Inclusion Criteria:

1. present of chronic disabling refractory angina pectoris (Canadian Cardiovascular Society [CCS] classes 2-4) despite maximally tolerated anti-angina medical therapy
2. Heart team evaluation with consideration of ineligibility for percutaneous or surgical revascularization procedures.

Exclusion Criteria:

1. recent acute coronary syndrome (<3 months),
2. recent coronary revascularization (<3 months)
3. a mean right atrial pressure higher than 15 mm Hg
4. coronary sinus proximal diameter <10mm and >14mm
5. life expectancy under 12 months,
6. advanced heart failure (New York Heart Association [NYHA] Classification - classes 3-4),
7. potential implantable cardiac resynchronization therapy defibrillator (CRT-D) implantation candidate.

The study population will consist of subjects with chronic disabling refractory angina pectoris (Canadian Cardiovascular Society [CCS] classes 2-4) who have not responded to treatment with maximally tolerated anti-angina medical therapy. The local Heart Team will evaluate all patients and determine that they are not suitable for percutaneous or surgical revascularization procedures. Following the Heart Team evaluation, patients who do not have any revascularization options available to them are eligible for the procedure or Coronary Sinus Reducer implantation, unless they meet one of the exclusion criteria.