What is that
By-pass is a delicate but well-established surgical technique used when the coronary arteries of the heart constrict, or even become occluded, due to atherosclerosis or other pathologies.
We recall how the coronary arteries are responsible for transporting blood to the heart muscle; consequently, their obstruction causes a reduced supply of blood, oxygen and nutrients to the heart muscle.The cells of the heart thus enter a state of suffering, which can lead to serious cardiovascular events, such as
- angina pectoris (transient deficiency in blood flow, responsible for oppressive pain behind the breastbone);
- or heart attack (irreversible death of heart muscle tissue, resulting from prolonged obstruction of one or more coronary arteries).
How it is done
By means of the bypass operation, an artificial bridge is created that allows the obstacle to circulation to be circumvented. This bridge, called bypass, is made up of a healthy and well-functioning stretch of blood vessel, which is taken by the surgeon at the same time as the operation. Whenever possible, some segments of the patient's mammary arteries (which have functional characteristics) will preferably be used optimal for carrying out the bypass action in the best possible way); alternatively, sections of the saphenous vein (venous branch of the lower limbs) are used.
These vascular segments are then grafted upstream and downstream of the occluded coronary artery, creating the famous bypass; this expedient allows an optimal supply of blood and oxygen to flow back to the heart.
Since the early 1970s, when the aortocoronary bypass technique began to take hold, surgical techniques have considerably evolved. From the traditional surgery in general anesthesia and extracorporeal circulation (the heart is stopped and an external machine is used to circulate blood), in more recent times interventions that can be performed with a beating heart and even under local anesthesia have been reached.
Risks and Consequences
As mentioned, the choice of the vessel to be used as a bypass is very important to ensure a longer life and to reduce the risk of this undergoing major degeneration (obstructions, etc.). According to some statistical data, about 40% of venous bypasses and 95% of arterial ones are well functioning after ten years from the operation.
In general, the mortality of the surgery is close to 1%, very little if we consider the high risk of myocardial infarction that patients who are candidates for the operation would face.
An alternative intervention to coronary artery bypass grafting is represented by angioplasty (the occluded artery is dilated by means of an inflatable balloon introduced with a catheter, then a special net called stent is applied to prevent re-occlusion). Certainly less invasive than bypass, it is suitable for patients in whom surgery is contraindicated.
Indications
In general, bypass is used in young patients (aged less than 70 years), with severe occlusions of several coronary arteries and at high risk of adverse cardiovascular events, not preventable with medical therapy alone.
The latter is based on pharmacological treatments (beta-blockers, calcium antagonists, acetylsalicylic acid, etc.) and on behavioral corrections that must in any case be undertaken even while waiting for and after the bypass surgery (smoking abolition, weight reduction, stress control and motor activity aimed at improving the efficacy of the cardiovascular system).
