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Like conventional bypass surgery, off-pump coronary artery bypass surgery is an operation that treats blocked coronary arteries , which are the arteries that supply the heart with oxygen-rich blood. By dramatically improving the flow of oxygen-rich blood to the heart (a process called revascularization ), off-pump bypass greatly reduces the risk of chest pain /pressure/discomfort ( angina ), heart attack and death. 
Off-pump bypass involves the same two procedures that are performed
during traditional bypass surgery. In the first, the surgeon
removes ( harvests ) one of the patient's blood vessels
– usually either the saphenous vein in the leg or the mammary
artery. In the second procedure, the surgeon uses the blood
vessel to create a detour ( bypass graft ) around the
blockages in the coronary arteries. Off-pump bypass allows the surgeon to sew the bypass grafts into place in the chest without stopping the heart. This eliminates all risks associated with stopping the heart (which is necessary during traditional bypass surgery). It also reduces the risk that a patient will experience depression and/or mood swings – a not uncommon side effect with traditional bypass surgery. Following the vein harvesting, the surgeon will make an 11- to 12-inch incision in the chest, cutting through the breastbone ( sternum ). The two halves of the breastbone will be divided ( median sternotomy ), and a retractor will be used to pull back the two halves of the breastbone to give the surgeon plenty of room to work. The ribs are not divided, thereby reducing discomfort during recovery. The surgeon will then use certain heart stabilizers and positioners to keep the targeted region of the heart virtually motionless while he or she is working on a particular coronary artery. The stabilizers restrict the heart's motion to create a stable and nearly still work area for the surgeon as he or she completes this very delicate surgery. The next step is to sew the bypass graft into place in the chest. For each blockage, the surgeon will graft one end of the harvested vein to a larger artery (e.g., the aorta ) and will sew the other end into place beyond the blockage in the coronary artery. Once this is finished, blood can flow freely through the bypass graft, around the blockage and into the coronary artery, restoring healthy blood flow to the heart muscle. During traditional bypass surgery, the surgeon stops the heart is in order to perform this procedure, and a heart-lung machine ("pump") takes over the functions of the heart and lungs for about 90 minutes. In contrast, off-pump bypass only requires the heart to be stabilized with special equipment. The avoidance of the heart-lung machine eliminates any risk of complications from the machine (e.g., stroke , memory problems after surgery, or postpump syndrome ). In addition, bleeding is greatly reduced, so patients are less likely to need a blood transfusion. When the surgeon is satisfied that complete blood circulation has been restored to the heart, the surgical site will be carefully closed layer by layer. The sternum will be closed, usually with wire, and the surface incision will closed with staples or sutures, depending on the surgeon's preference. The entire surgery takes approximately two to five hours. Advances in technology now allow off-pump bypass surgery to be combined with another minimally invasive technique, one that allows the surgeon to harvest the saphenous vein with one to three small incisions. This type of bypass is called off-pump coronary revascularization with endoscopic vein harvesting ( OPCRES ).  |