The heart is actually a muscular hollow organ. Through the regular contraction of the heart muscle, it pumps oxygen-rich blood throughout the body. The heart must beat day and night; otherwise, organs that are not receiving enough blood would die within minutes.
But this also applies to the heart itself. The heart muscle needs oxygen to function. The coronary arteries (coronary vessels) are responsible for supplying the heart muscle with oxygen. If not enough oxygen-rich blood reaches the heart, it can no longer beat—and the person suffers a life-threatening heart attack.
Such a situation can occur due to a narrowing of the coronary arteries (coronary stenosis) or a sudden blockage.
Bypass surgery creates a detour around narrowed or blocked coronary arteries © lom123 | AdobeStock
Coronary stenosis is most often caused by atherosclerosis, colloquially known as “hardening of the arteries.” In the case of narrowing of the coronary arteries, the term “coronary heart disease” is used more precisely.
As the coronary arteries become increasingly narrowed, an imbalance develops between oxygen demand and supply (coronary insufficiency). This results in shortness of breath and a tightness in the chest (angina pectoris).
Over time, atherosclerosis can cause the coronary arteries to become completely blocked. However, a blood clot can also suddenly block such a vital blood vessel.
In coronary artery bypass surgery (also known as coronary artery bypass), the blood supply to the heart muscle is rerouted around narrowed or blocked coronary arteries. The surgery is performed under general anesthesia and is one of the most common procedures in cardiac surgery. For patients with coronary artery disease (CAD), bypass surgery can alleviate symptoms and prevent complications such as heart attacks.
Bypass surgery is performed under general anesthesia; access to the heart is usually gained through the sternum. The surgeon often uses the left internal mammary artery (LIMA) for the front wall of the heart below the left breast; alternatively, veins are used as bypass grafts.
As a rule, before bypass surgery, doctors assess whether the narrowed coronary artery can be sufficiently widened through medication or interventional procedures—such as balloon angioplasty with or without a stent.
Depending on the extent and location of the bypass, the procedure usually takes two to five hours. The chest is often opened by making an incision in the sternum (sternotomy), allowing the surgeon to operate on the heart under direct visualization; in select cases, minimally invasive procedures involving small incisions are possible.
Chest wall arteries and veins (e.g., from the leg) are usually used as bypass grafts; artificial prostheses are used less frequently. The vessels are connected to the coronary artery above and below the narrowing(s); veins adapt functionally to the higher pressure load.
The aorta (main artery) often serves as the connection point for the coronary artery.
Bypass Methods (Brief Overview):
- Arterial bypass: A thoracic artery running along the inner side of the chest wall is connected to the coronary artery. Advantages: proximity to the heart, long-term durability, low risk of reocclusion.
- Venous bypass: A vein from the upper or lower leg is harvested and sutured into the coronary artery as a bypass.
- Artificial bypass: Rarely used today, as deposits can impair its function.
The choice of procedure depends on the narrowing or blockages in the coronary arteries (also called stenoses) and the severity of coronary artery disease (CAD).
Depending on the situation, the bypass surgery is performed using a heart-lung machine on a stopped heart or as off-pump coronary artery bypass grafting (OPCAB) on a beating heart.
Traditionally, aortocoronary bypass surgery is performed as open-heart surgery using a heart-lung machine. During this procedure, the heart is temporarily stopped (“off-pump”), and the machine takes over the pumping function and gas exchange—that is, the supply of blood and oxygen.
If the patient’s anatomy is suitable, coronary artery bypass surgery can also be performed on a beating heart (OPCAB). In this case, the use of a heart-lung machine is not necessary; special stabilization systems keep the area being sutured still.
What does this mean for you?
- With a heart-lung machine (on-pump): a proven standard procedure that provides the surgeon with a very clear view; suitable when there are multiple narrowings or complex sutures on the coronary arteries are required.
- OPCAB (off-pump): Surgery on a beating heart without a heart-lung machine; may offer advantages for selected patients, such as reduced fluid shifts, but is technically more demanding.
The cardiac surgery team decides which method to use on a case-by-case basis—depending on the location and number of narrowings, comorbidities, and the team’s experience.
In OPCAB, coronary bypass surgery is performed on a beating heart without the use of a heart-lung machine.
Immediately after surgery, patients are closely monitored in the intensive care unit. Tubes and drains are gradually removed, and pain management and breathing exercises support recovery.
Early mobilization begins in the first few days after surgery: Patients are usually able to get out of bed and walk around after one to three days. Follow-up rehabilitation can begin as early as ten to twelve days after heart surgery, depending on the patient’s progress. It is important to monitor blood pressure and blood sugar levels, undergo respiratory therapy, and care for the incision site on the chest/sternum.
Possible symptoms and risks: A pulling sensation in the chest and shoulder area is not unusual at first; physical therapy often alleviates these symptoms. As with any surgical procedure, complications are possible (e.g., bleeding, cardiac arrhythmias, wound healing complications). The team will inform you which symptoms should be evaluated by a doctor.
Long-term: The risk of atherosclerosis remains. Lifestyle changes (quitting smoking, exercise, diet) and the prescribed anticoagulant therapy are crucial to ensuring that the bypasses remain open. Regular checkups (e.g., annually) monitor the bypasses and remaining coronary arteries for narrowing or blockages—this allows problems to be detected and treated early. Individual life expectancy depends, among other things, on risk factors, comorbidities, and cardiac output.
Which hospitals perform bypass surgery?
Bypass surgeries are performed at specialized cardiac surgery centers (heart centers). These centers are staffed by a well-coordinated team of cardiac surgeons, cardiologists, anesthesiologists, and intensive care specialists—which is crucial because diagnosis, surgery, and postoperative care must be seamlessly integrated. Minimally invasive procedures and off-pump coronary artery bypass grafting (OPCAB) also require a great deal of experience.
How can you identify a suitable clinic? (Quick checklist)
- Experience & Scope: The center offers both on-pump (with a heart-lung machine) and OPCAB procedures and routinely uses standard chest wall arteries and veins as bypass grafts.
- Interdisciplinary cardiac team: Joint case discussions between cardiology and cardiac surgery; clear determination of indications for coronary artery disease (CAD).
- 24/7 Infrastructure: Cardiac catheterization on-call service, intensive care unit with cardiac surgery expertise, capability to treat complications.
- Quality & Transparency: Access to quality reports and outcomes; structured infection control and pain management protocols; standardized rehabilitation coordination.
- Patient Information: Preoperative consultations regarding anesthesia, access route (sternum/small incisions), expected course of care (ICU/general ward), and postoperative medication (e.g., anticoagulation).
Note: Minimally invasive bypass surgeries and complex multivessel procedures, in particular, should be performed by experienced teams. If you are unsure, it is advisable to seek a second opinion at a recognized cardiac center. Cardiac surgeons will advise you on which method is most likely to benefit you in your specific case.
