There are a number of other procedures or variations of the bypass that are being used or considered as alternatives. In general, two main alternatives have emerged. The first is known as minimally invasive direct coronary artery bypass surgery, or MIDCAB for short. MIDCAB surgery is performed through smaller incisions, often in the side of the chest, rather than the large, frontal sternotomy. This is sometimes referred to as “keyhole” surgery. In some centers, MIDCAB surgeries are performed with the use of advanced robots, although this remains very limited.

The second major alternative to conventional bypass surgery is known an off-pump coronary artery bypass surgery, or OPCAB. During this procedure, the surgeon operates on a beating heart. The heart-lung machine is not used, and the heart is not stopped. Instead, the surgeon uses special stabilizers and other techniques to isolate the coronary arteries and operate on them. The major advantage to this surgery is avoiding any potential complications involved with the bypass machine.

There can be overlap between these alternatives and the more conventional bypass surgery and therapy. For instance, a MIDCAB surgery can be performed without using the heart-lung machine, so it is also off-pump. Similarly, an off-pump surgery may be performed using a sternotomy, so it is comparable in recovery time to a conventional bypass surgery.

There are relative advantages and disadvantages to each of the newer procedures. However, MIDCAB surgery faces greater obstacles to widespread acceptance than OPCAB. Because the incisions are smaller, surgeons are limited in their ability to reach certain areas of the heart during MIDCAB surgery. Thus, studies have looked at combining MIDCAB on one coronary artery (e.g. the left anterior descending coronary artery) with conventional balloon angioplasty on other coronary arteries. At this time, however, MIDCAB remains significantly more expensive and technically demanding than conventional and OPCAB surgeries and there are no long-term studies on its results.

Minimally invasive techniques have also migrated to the harvesting of veins for the bypass grafts. In this procedure, a surgeon uses a special device called an endoscope to remove the leg vein (the saphenous vein) through small incisions. This is called endoscopic vein harvesting. It may be used with either conventional bypass surgery, or it may be used with OPCAB in a series of procedures known as off-pump coronary revascularization with endoscopic saphenous vein harvesting (OPCRES). 

With advancing technology and experience, OPCAB- with or without endoscopic vein harvesting – has become relatively widespread. The Society of Thoracic Surgeons estimated that in 2001, “beating heart” surgeries accounted for 25 percent of bypass operations. Initial studies show that OPCAB has approximately the same results as conventional bypass surgery, and because the surgeon is usually operating in a wide field through a sternotomy, it can be used for multi-vessel disease.

A number of even less invasive techniques may be used to treat a blocked artery. For example, many patients are recommended for balloon angioplasty with stenting. This technique uses an inflatable balloon that crushes plaque against the wall of the artery to improve blood flow. This procedure is usually followed by placement of a coronary stent – a wire mesh metal tube – into the artery to hold it open afterward. 

Catheter-based techniques such as this are less invasive and less expensive than standard bypass surgery. On the other hand, they may need to be repeated sooner than would a bypass. Many first-time bypasses – between 70 and 90 percent, depending on the blood vessel used for the graft – remain open for 5 to 10 years or longer, whereas about 20 percent of catheter-based procedures that use a balloon and stent combination may need to be repeated within the year. Newer stents, called drug-eluting stents, are coated with special medications that further reduce the closure rate, to less than 10 percent. However, newer research has called into question the long-term performance of some drug-eluting stents, and researchers are currently reevaluating the decision to use a traditional or drug-eluting stent.

At least in some patients, it appears that drug-eluting stents may increase the long-term risk of blood clots, with possibly devastating consequences. One study indicated that patients who stop taking their prescribed medicines early are at a higher risk of blood clots than patients who continued to follow their prescriptions. Nevertheless, as a result of advances in stent design, the number of stent procedures has increased, whereas the number of bypass operations has decreased over the past 10 years. 

Some researchers are hoping that therapeutic angiogenesis may one day offer the benefits of a bypass with still less invasiveness. Therapeutic angiogenesis is an experimental treatment for angina, which is a common symptom of the cardiac ischemia that often results from coronary artery disease. Angina is a chest pain, pressure or discomfort that often results from usually temporary episodes of cardiac ischemia – an episode in which the heart does not get enough oxygen–rich blood. In response to this situation, the body often forms new blood vessels (collaterals) that bring more oxygen-rich blood to the heart, relieving cardiac ischemia and angina. This natural process is called angiogenesis. Researchers are attempting to medically coax the body to produce its own natural response of angiogenesis to lessen the need for bypass surgery.