Saturday, 28 September 2019

Coronary Artery Bypass Grafting

Coronary Artery Bypass Grafting(CABG)

Coronary Artery Bypass Grafting

Coronary Artery Bypass Grafting (CABG) is a procedure to treat severe Coronary Heart Disease (CHD) or Coronary Artery Disease (CAD)usually caused by atherosclerosis which builds up plaque on the artery walls causing by the lumen of the arteries to become narrower. This slows down the flow of blood. Coronary artery disease can be diagnosed by electrocardiogram (EKG), Treadmill stress test, Cardiac catheterization, etc. If the blockages are significant enough, the end result will be a heart attack or sudden death. CABG surgery is performed to treat narrowed and blocked arteries, allowing sufficient blood flow to the deliver oxygen and nutrients to the heart muscle. CABG began in the late 1960s along two parallel paths that are included bypassing coronary artery obstructions using either the Internal Mammary Artery (IMA) the bypass conduit or reversed Saphenous Vein Graft (SVG) from the legs. The use of the latter became the dominant approach as it could be used to graft any coronary artery site.
Coronary Artery Bypass Grafting

CABG Procedure Steps

The majority of patients who undergo CABG surgery today receive a left IMA graft to the left anterior descending coronary artery and reversed saphenous vein grafts with proximal aortic anastomoses.

(1) Different types of surgical accesses are used in CABG, but the most common name is sternotomy. In sternotomy, the cardiac surgeon makes an incision down the middle of the chest (A – B) and then saws through the breastbone (sternum).

CABG Procedure Steps

(2) After the cut, in case of off-pump surgery, the surgeon places devices to stabilize the heart. This type of surgery is called beating heart bypass grafting because the heart does not stop beating and a heart-lung bypass machine (cardiac pulmonary bypass) is not used. In case of on-pump coronary artery bypass grafting, cardiac pulmonary the bypass has to be established by arterial cannulation onto the aortic arch and venous cannulation through the right atrial appendage into the inferior vena cava.

Coronary Artery Bypass Grafting

(3) Greater Saphenous Vein (GSV) of the lower extremity is harvested in two different ways. First, directly through multiple incisions and tunneling over vein along the medial thigh and leg. Second, endoscopic vein harvest in which two small incisions are made by one above the knee and the second on the upper thigh.

Coronary Artery Bypass Grafting

(4) When harvesting is done, heparin is given to inhibit blood clotting. The saphenous vein is slightly tilted and anastomosed to the coronary artery with a single suture.

Coronary Artery Bypass Grafting

(5) In the case of the Internal Mammary Artery (IMA) graft, the internal mammary artery is anastomosed to the Left Anterior Descending coronary artery (LAD). Once an adequate IMA
with pedicle (artery with surrounding tissue) is determined, the LAD is the incised and the IMA incised on an angle at an appropriate distal site.

Coronary Artery Bypass Grafting

(6) The final stage of the grafting procedure is the construction of proximal vein graft anastomoses. The aorta wall punch is used to create opening in the aorta for anastomoses and the distal segment of the vein graft is ana composed with the aorta.

Coronary Artery Bypass Grafting

(7)After the grafting is done, the heart is restarted (in case of on-pump) or the stabilizing devices are removed (in case of off-pump). Protamine is given to the patient to reverse the effects of heparin. Chest tubes are placed in the mediastinal and pleural space to drain blood from around the heart and lungs. The sternum is wired together and the incisions are sutured closed.

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