Coronary artery bypass surgery

Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG, pronounced "cabbage") surgery, and colloquially heart bypass or bypass surgery, is a surgical procedure to restore normal blood flow to an obstructed coronary artery. A normal coronary artery transports blood to and from the heart muscle itself, not through the main circulatory system.

CABG is performed to relieve angina unsatisfactorily controlled by maximum tolerated anti-ischemic medication, prevent or relieve left ventricular dysfunction, and/or reduce the risk of death. CABG does not prevent myocardial infarction (heart attack). This surgery is usually performed with the heart stopped, necessitating the usage of cardiopulmonary bypass. However, two alternative techniques are also available, allowing CABG to be performed on a beating heart either without using the cardiopulmonary bypass, a procedure referred to as "off-pump" surgery, or performing beating surgery using partial assistance of the cardiopulmonary bypass, a procedure referred to as "on-pump beating" surgery. The latter procedure offers the advantages of the on-pump stopped and off-pump while minimizing their respective side-effects.

The surgeon reviews the coronary angiogram prior to surgery and identifies the number of obstructions, the percent obstruction of each, and the suitability of the arteries beyond the obstruction(s) as targets. The presumed number of bypass grafts needed as well as the location for graft attachment is determined in a preliminary fashion prior to surgery, but the final decision as to number and location is made during surgery by direct examination of the heart.

Veins that are used either have their valves removed or are turned around so that the valves in them do not occlude blood flow in the graft. External support may be placed on the vein prior to grafting into the coronary circulation of the patient. LITA grafts are longer-lasting than vein grafts, both because the artery is more robust than a vein and because, being already connected to the arterial tree, the LITA need only be grafted at one end. The LITA is usually grafted to the left anterior descending coronary artery (LAD) because of its superior long-term patency when compared to saphenous vein grafts.

Hybrid Coronary Revascualrisation, where the LIMA-to-LAD anastomosis is combined with percutaneous stents in other atherosclerotic sites, has been shown to have significant advantages compared to conventional CABG, including a decrease in the incidence of blood transfusion, and a reduced intubation time. A 2018 meta-analysis has however demonstrated a greater financial cost when compared to conventional CABG.

CABG is one of the most common procedures performed during U.S. hospital stays; it accounted for 1.4% of all operating room procedures performed in 2011. Between 2001 and 2011, however, its volume decreased by 46%, from 395,000 operating procedures performed in 2001 to 213,700 procedures in 2011.

The first coronary artery bypass surgery was performed in the United States on May 2, 1960, at the Albert Einstein College of Medicine-Bronx Municipal Hospital Center by a team led by Robert H. Goetz and the thoracic surgeon, Michael Rohman with the assistance of Jordan Haller and Ronald Dee. In this technique the vessels are held together with circumferential ligatures over an inserted metal ring. The internal mammary artery was used as the donor vessel and was anastomosed to the right coronary artery. The actual anastomosis with the Rosenbach ring took fifteen seconds and did not require cardiopulmonary bypass. The disadvantage of using the internal mammary artery was that, at autopsy nine months later, the anastomosis was open, but an atheromatous plaque had occluded the origin of the internal mammary that was used for the bypass.