In the United States, 8 to 12 million people have symptomatic peripheral artery disease or occlusive disease of the arteries. The number-one cause of this disease is cholesterol deposits in the arteries, or atherosclerosis. Other risk factors include cigarette smoking, diabetes, hypertension, age and male gender. Five to 10 percent will require lower-extremity bypass surgery to eliminate pain, according to "The 5-Minute Clinical Consult" textbook. Clot formation in the grafts, infection and reperfusion injury are complications of vascular surgery.
Reperfusion Injury
According to "Sabiston Textbook of Surgery," reperfusion injury is a well-studied phenomenon. Muscles that have been deprived of oxygen for a long time react to the reestablishment of blood flow by releasing many different chemical components into the circulatory system. Injured muscle cells release myoglobin, a protein found in muscle, into the blood stream. The protein is subsequently filtered through the kidneys and can cause kidney failure. Edema of the muscles can create a painful condition called compartment syndrome. This edema causes so much swelling in the muscles, that compression cuts off the blood supply and causes pain and tissue destruction. Patients with reperfusion syndrome are unstable, have severe low blood pressure and will require monitoring in intensive care.
Infection
Infection of a bypass graft is a catastrophic complication, as noted in Sabiston. Infection of a graft may require removal of the graft and possible subsequent amputation of the extremity. Grafts become infected because of poor technique in placing the graft, seeding from another source of infection and/or wound complications that result in exposure of the graft. Synthetic grafts are more likely to become infected than vein grafts. Wound debridement, or surgical excision of dead tissue, and aggressive intravenous antibiotics are required.
Occlusion of the Graft
Reblockage, or occlusion, of the new graft within the first two months, is usually caused by technical or judgmental errors, as explained in Sabiston. Placement of the graft, type of graft used and suturing technique can contribute to early graft occlusion. Patients may complain of increased pain in the hospital and lose their newly acquired pulse in the lower extremity. The wound may not heal well and tissue in the wound may die, requiring excision. Grafts that occlude within two years are generally attributable to an overgrowth of the lining of the vein at the site where it was sutured. Occlusion of the graft may require further surgical intervention.
References
- "The 5-Minute Clinical Consult 2010", 18th ed.; Frank J. Domino, M.D., editor; 2009
- "Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice"; Courtney Townsend, M.D. et al.; 2008.
