Coronary bypass surgery

The aim of treatment of CHD is to improve the circulation in the areas of heart muscle under threat by means of bypasses. The bypass is similar to what happens with roads: saturated blood is diverted past the narrowed or blocked parts of the coronary arteries and ultimately back into a healthy terminal segment. Coronary bypasses abolish the angina and produce markedly prolonged survival.

The indication for bypass surgery is main stem stenosis, three-vessel disease when the bypass can be joined to the distal coronary arteries, two-vessel disease involving the LAD (with left-dominant supply), a change in the angina symptoms despite adequate medical therapy and stenoses in anatomically difficult locations (very close to the origin of the artery or at sites of branching). Diabetics and patients with renal failure in particular are referred for bypass surgery more often by cardiologists than are treated with PTCA and stents on account of the complex stenoses. It is also indicated in patients with two-vessel disease and a reduction in pump function (ejection fraction below 50%) and patients with valvular heart disease, aortic aneurysms or stenosis of the carotid arteries in addition. Dilatation, imminent cardiogenic shock and acute coronary syndrome (ACS) prior to the onset of infarction are emergency indications. Immediate bypass surgery using a heart-lung machine is not possible when a major myocardial infarction has just occurred but only after an interval of at least 2 weeks so that other stenosed arteries can be treated. In the case of an unstable patient, a bypass operation can also be performed on the beating heart without cardioplegia to stop the heart and with the aid of a stabilisation system (see: OPCAB). In a life-threatening emergency, the cardiac surgeon can also offer patients a system for mechanical circulatory support ("assist device").