Blocked coronary arteries must be treated surgically to prevent the patient from suffering a heart attack, or to quickly restore the flow of blood to the heart muscle after a heart attack. There are a variety of treatment options available, such as balloon dilatation, a coronary stent or a bypass operation.
The coronary arteries, also known as coronary vessels, encircle the heart like a crown and ensure the blood flow to the heart. If the coronary arteries become blocked or narrowed due to a build-up of deposits (arteriosclerosis), this can cause the coronary disease angina pectoris; a completely blocked coronary artery will trigger a heart attack.
Modern medicine has various techniques for widening, opening or bypassing narrowed or blocked coronary arteries. The aim of such surgery is to prevent a heart attack or, if the patient has already suffered a heart attack, to quickly restore the blood flow.
Percutaneous transluminal coronary angioplasty, PTCA, balloon dilatation, coronary stent
If narrowed coronary arteries still need to be widened or opened, percutaneous transluminal coronary angioplasty is usually performed in a heart catheter laboratory. This operation, which was invented in Switzerland, is performed via an incision in the groin (occasionally in the arm). X-ray imaging is then used to monitor the insertion of a balloon catheter into an artery, where it is pushed all the way through to the narrowed coronary artery. Once it has reached the narrow section, the balloon is inflatedusing liquid, thereby widening the blocked artery.
Sometimes drug-releasing balloon catheters are used, which involve a balloon coated with medication. When the balloon is inflated, medication which prevents cell growth in the artery walls is applied to the affected area.
A delicate, flexible tube made from metal or plastic mesh (known as a coronary stent) is usually inserted into the vessel at the same time or afterwards to support it and keep it open in the longer term. The stent is also often coated with medication designed to prevent unwanted cell growth, which could potentially block the stent.
What preparations are carried out before the operation?
First a coronary angiography is performed using an x-ray contrast agent to locate the narrowed coronary arteries. Prior to surgery, the patient may also have to stop taking blood-thinning medication. If it is a planned operation and not an emergency, the patient must not consume food or drink prior to the procedure. A blood test and an ECG are usually also performed beforehand. In addition, an infusion may be attached to a vein in the patient’s arm if access to a vein is required.
How is the procedure performed?
The patient is usually conscious during a percutaneous coronary angioplasty procedure; however, they do receive a mild sedative. The area where the incision is made is numbed using a local anaesthetic. The insertion of the catheter into the coronary artery does not cause any pain. Sometimes the patient may experience temporary chest pain when the balloon catheter is inflated. The injection of the contrast agent used to identify the coronary arteries may cause a warm sensation. The procedure takes one to two hours. In general, the patient can leave the hospital one day after the operation (at the latest), as long as it was not an emergency procedure following a heart attack.
What is the success rate of this procedure?
The success rate of coronary angioplasty with a stent implant is very good – over 90%. Optimal blood flow to the heart is usually completely restored and symptoms like angina pectoris disappear.
What are the possible complications and risks of this procedure?
This procedure is low-risk and in most cases does not result in complications. In rare cases, the balloon catheter cannot be pushed through the narrowed section, or the procedure can cause vascular occlusion, which may trigger a heart attack. In such instances, a bypass operation is performed immediately.
What happens after the operation?
Patients can generally resume all their normal daily activities one week after a balloon angioplasty or a stent implant procedure. However, it takes a few more weeks before they can effectively perform more strenuous tasks. Patients should take great care to maintain a healthy lifestyle, in order to minimise the progression of arteriosclerosis. This includes a balanced, healthy diet, regular exercise and no smoking.
Bypass operation, aortocoronary bypass
If the blocked or narrowed coronary arteries cannot be opened with a percutaneous transluminal angioplasty procedure, a bypass operation is required. This operation is used to bypass the coronary arteries using the body’s own blood vessels.
What preparations are carried out before the operation?
Bypass operations are typically open heart operations. The surgery is therefore performed under general anaesthetic. All the usual pre-operative assessments are required, such as a blood test, blood pressure measurement and an ECG. The patient may also have to stop taking blood-thinning medication. The patient is admitted to hospital on the day before the surgery. They should not consume food or drink before the operation.
Recently surgeons have also begun carrying out the procedure using a minimally invasive technique, whereby the heart is accessed via just a small incision. This minimally invasive technique can be used if no more than three of the coronary arteries are blocked.
The following information refers to the open heart operation, which is still the standard procedure.
How is the operation performed?
During an open bypass operation, the breastbone (sternum) is separated to gain access to the heart. In most cases, the narrowed coronary arteries are bypassed using arteries in the chest wall. They are a suitable size and can be removed without any difficulty, because there are other arteries that will continue to supply the chest wall with blood. Often a section of vein from the patient’s leg is also used. The heart is temporarily immobilised using a cardioplegic solution and the patient’s circulation is maintained using a life-support machine, so that the ‘bridging’ blood vessels can be sewn onto the coronary arteries. The other end of the ‘bridging’ vessels are then directly connected to the main artery (aorta). That way, the blocked arteries are bypassed and blood can once again flow smoothly through the heart. After the cardioplegic solution has been flushed out, the heart automatically starts beating again. The operation usually takes around three hours.
Sometimes the OPCAB method is used (off-pump coronary artery bypass) instead of a life-support machine. This method involves using stabilisers to keep the surface of the heart over the coronary arteries as still as possible, so that the ‘bridging’ vessels can be sewn on while the heart is still beating.
What is the success rate of this procedure?
Bypass operations have excellent long-term results. In around 90 per cent of all patients, the ‘bridging’ vessels still work flawlessly twenty years after the procedure.
What are the possible complications and risks of this procedure?
Bypass surgery is a routine operation. As with all surgery, the operation may lead to risks and complications in rare cases. These include infections, post-operative haemorrhaging and the formation of blood clots (thromboses). Complications that do occasionally arise can usually be effectively treated.
What happens after the operation?
People who have undergone this operation should avoid lifting heavy objects and major physical exertion until their wounds have fully healed. After the bypass operation, patients are recommended to complete a rehabilitation programme lasting at least four to six weeks in order to regain a suitable level of cardiovascular fitness. During the rehabilitation programme, they will also receive information about how to maintain a heart-healthy lifestyle. It usually takes around 12 weeks for them to regain their full strength and stamina, and regular check-ups will be scheduled to test the functioning and performance of their heart.
