Aortocoronary bypass or coronary bypass – an operation that allows to restore blood flow in the arteries of the heart (coronary arteries) by bypassing the narrowing of the coronary vessel with shunt.
Aortocoronary bypass refers to surgical methods to treat coronary heart disease, which are aimed at directly increasing coronary blood flow, ie, myocardial revascularization.
Indications for myocardial revascularization (coronary bypass surgery)
The main indications for myocardial revascularization are:
- severe angina pectoris, resistant to medication therapy,
- Prognostically unfavorable coronary channel lesions – proximal hemodynamically significant lesions of the trunk and main coronary arteries with narrowing by 75% or more and passable distal channel,
- preserved contractile function of left ventricle myocardium 40% and higher.
Contraindications to aortocoronary bypass
Traditionally, the following are considered: diffuse lesions of all coronary arteries, a sharp drop in the left ventricle to 30% or less as a result of scarring, clinical signs of congestive heart failure. There are also general contraindications in the form of severe concomitant diseases, in particular, chronic non-specific diseases of the lungs, renal failure, cancer. All these contraindications are relative. Adult age is also not an absolute contraindication to myocardial revascularization, that is, it is more correct to speak not about contraindications to aortocoronary bypass, but about operational risk factors.
Technique of myocardial revascularization operation
Surgery aortocoronary bypass involves creating a bypass pathway for blood bypassing the affected (stenozed or occluded) proximal segment of the coronary artery. There are two main methods to create a bypass pathway: mammarocoronary anastomosis and aortocoronary bypass with an autovenous (own vein) or autoarterial (own artery) graft (conduit).
In mammarocoronary bypass, the inner mammary artery is used, it is usually “switched” to the coronary channel by anastomoses with the coronary artery below the stenosis of the latter. The inner pectoral artery is filled naturally from the left subclavian artery, from which it departs.
In aortocoronary bypass, the so-called “free” conduits (from a large saphenous vein, radial artery or internal thoracic artery) are used to anastomize the distal end with the coronary artery below the stenosis, and the proximal end with the ascending aorta.
First of all, it is important to emphasize that aortocoronary bypass is a microsurgical operation, because the surgeon works on arteries with a diameter of 1.5-2.5 mm. It was the awareness of this fact and the introduction of precision microsurgical techniques that ensured the success that was achieved in the late 70s – early 80s of the last century. The operation is performed with the use of surgical binocular magnifying glasses (x3-x6 magnification), and some surgeons operate with the use of an operating microscope, which allows achieving x10 – x25 magnification. Special microsurgical instruments and fine atraumatic filaments (6/0 – 8/0) allow to form distal and proximal anastomoses with maximum precision. The operation is performed under a general multi-component pain relief, and in some cases, especially when performing operations on the beating heart, additionally use a high epidural anesthesia.