2 The condition, current treatments and procedure
2.1 Angina is pain or constricting discomfort that typically occurs in the front of the chest (but may radiate to the neck, shoulders, jaw or arms). It is brought on by physical exertion or emotional stress. Some people can have atypical symptoms, such as gastrointestinal discomfort, breathlessness or nausea. Angina is the main symptom of myocardial ischaemia. It is usually caused by atherosclerotic obstructive coronary artery disease restricting blood flow and therefore oxygen delivery to the heart muscle. Being diagnosed with angina can have a significant effect on a person's quality of life, restricting daily work and leisure activities.
2.2 NICE's guideline on stable angina describes recommendations on managing stable angina. Options include lifestyle advice, drug treatment and revascularisation using percutaneous or surgical techniques.
2.3 Coronary sinus narrowing device implantation is indicated for angina when other treatment options (medical or surgical) have failed or are not possible (refractory angina). The aim is to reduce symptoms and to improve quality of life.
2.4 The coronary sinus is a large venous structure formed by the merging of veins that drain blood away from the myocardium. It receives most of the cardiac venous blood, which then flows into the right atrium (along with deoxygenated blood from the superior and inferior venae cavae).
2.5 This procedure uses a percutaneously inserted, balloon-expandable device to narrow the coronary sinus. In current practice, an hourglass-shaped device made of stainless steel mesh is used. The device is put into the main vessel of the coronary sinus by a catheter in the right side of the heart, typically through the right or left jugular vein. To define and measure the most suitable position for the device, injected contrast is used to visualise the anatomy of the coronary sinus. A guiding catheter is then used to advance the device to the implantation site. The device is mounted on a balloon, which is inflated to expand it. Once the device is correctly placed, the balloon is deflated and the catheter pulled back. Imaging is used to confirm that there is 'hour-glass' device expansion in the coronary sinus.