Great Saphenous Vein Cutdown-The Great Saphenous Vein in Coronary Bypass Surgery

Great Saphenous Vein Cutdown

Exposure of the great saphenous vein through a skin incision (a“cutdown”) is usually performed at the ankle. This site has the disadvantage that phlebitis (inflammation of the vein wall) is a potential complication. The great saphenous vein also can be entered at the groin in the femoral triangle, where phlebitis is relatively rare; the larger diameter of the vein at this site permits the use of large-diameter catheters and the rapid infusion of large volumes of fluids

Anatomy of Ankle Vein Cutdown

The procedure is as follows:

1. The sensory nerve supply to the skin immediately in front of the medial malleolus of the tibia is from branches of the saphenous nerve, a branch of the femoral nerve.

The saphenous nerve branches are blocked with local anesthetic.

2. A transverse incision is made through the skin and subcutaneous tissue across the long axis of the vein just anterior and superior to the medial malleolus. Although the vein may not be visible through the skin, it is constantly found at this site.

3. The vein is easily identified, and the saphenous nerve should be recognized; the nerve usually lies just anterior to the vein

Anatomy of Groin Vein Cutdown

1. The area of thigh skin below and lateral to the scrotum or labium majus is supplied by branches of the ilioinguinal nerve and the intermediate cutaneous nerve of the thigh. The branches of these nerves are blocked with local anesthetic.

2. A transverse incision is made through the skin and subcutaneous tissue centered on a point about 1.5 in. (4 cm) below and lateral to the pubic tubercle . If the femoral pulse can be felt (may be absent in patients with severe shock), the incision is carried medially just medial to the pulse.

3. The great saphenous vein lies in the subcutaneous fat and passes posteriorly through the saphenous opening in the deep fascia to join the femoral vein about 1.5 in. (4 cm), or two fingerbreadths below and lateral to the pubic tubercle. It is important to understand that the great saphenous vein passes through the saphenous opening to gain entrance to the femoral vein. However, the size and shape of the opening are subject to variation.

The Great Saphenous Vein in Coronary Bypass Surgery

In patients with occlusive coronary disease caused by atherosclerosis, the diseased arterial segment can be bypassed by inserting a graft consisting of a portion of the great saphenous vein. The venous segment is reversed so that its valves do not obstruct the arterial flow. Following removal of the great saphenous vein at the donor site, the superficial venous blood ascends the lower limb by passing through perforating veins and entering the deep veins.

The great saphenous vein can also be used to bypass obstructions of the brachial or femoral arteries.

Coronary Artery Disease-Arteriosclerotic disease of the coronary arteries

Coronary Artery Disease

The myocardium receives its blood supply through the right and left coronary arteries. Although the coronary arteries have numerous anastomoses at the arteriolar level, they are essentially functional end arteries. A sudden block of one of the large branches of either coronary artery will usually lead to necrosis of the cardiac muscle (myocardial infarction) in that vascular area, and often the patient dies. Most cases of coronary artery blockage are caused by an acute thrombosis on top of a chronic atherosclerotic narrowing of the lumen

Arteriosclerotic disease of the coronary arteries

it may present in three ways, depending on the rate of narrowing of the lumina of the arteries: (1) General degeneration and fibrosis of the myocardium occur over many years and are caused by a gradual narrowing of the coronary arteries. (2) Angina pectoris is cardiac pain that occurs on exertion and is relieved by rest. In this condition, the coronary arteries are so narrowed that myocardial ischemia occurs on exertion but not at rest. (3) Myocardial infarction occurs when coronary flow is suddenly reduced or stopped and the cardiac muscle undergoes necrosis. Myocardial infarction is the major cause of death in industrialized nations.

Because coronary bypass surgery, coronary angioplasty, and coronary artery stenting are now commonly accepted methods of treating coronary artery disease, it is incumbent on the student to be prepared to interpret still- and motion-picture angiograms that have been carried out before treatment. For this reason, a working knowledge of the origin, course, and distribution of the coronary arteries should be memorized.

 

Internal Thoracic Artery in the Treatment of Coronary Artery Disease- Lymph Drainage of the Thoracic Wall

Internal Thoracic Artery in the Treatment of Coronary Artery Disease

In patients with occlusive coronary disease caused by atherosclerosis, the diseased arterial segment can be bypassed by inserting a graft. The graft most commonly used is the great saphenous vein of the leg. In some patients, the myocardium can be revascularized by surgically mobilizing one of the internal thoracic arteries and joining its distal cut end to a coronary artery.


 Lymph Drainage of the Thoracic Wall

 The lymph drainage of the skin of the anterior chest wall passes to the anterior axillary lymph nodes; that from the posterior chest wall passes to the posterior axillary nodes. The lymph drainage of the intercostal spaces passes forward to the internal thoracic nodes, situated along the internal thoracic artery, and posteriorly to the posterior intercostal nodes and the para-aortic nodes in the posterior mediastinum.