The coronary arteries supply the heart tissue with oxygen-rich blood. With coronary heart disease, deposition of fat-laden material, or plaques, within the arteries narrows the internal space, decreasing blood flow. Coronary artery bypass grafting, also known as cardiac bypass surgery or CABG, involves removing a section of blood vessel from another part of the body and sewing it to the coronary artery. This procedure bypasses the plaque-narrowed area and restores oxygen-rich blood flow to the heart. Although most CABG surgeries are successful, complications may arise.
Infection
Major infections remain a potential complication of CABG surgery. In a large 2005 study published in the journal "Circulation," Dr. Vance Fowler, Jr. and colleagues report that approximately 4 percent of CABG patients develop a major postoperative infection. The most common types of infection include bloodstream infections; infections at the surgical site from which the grafted vessels were harvested; and deep tissue infection of the chest surgical site, also known as mediastinitis.
Fowler and colleagues point out several factors associated with an increased risk of CABG-associated postoperative infection including obesity, previous heart attack, diabetes mellitus, high blood pressure, unplanned surgery, prolonged operative time, immunosuppressant medications and dialysis-dependent kidney failure. CABG patients who develop a major postoperative infection have a significantly increased risk of death compared to patients who do not develop an infection.
Stroke
Stroke is an uncommon but potentially catastrophic complication of cardiac bypass surgery. In a 2003 article published in the journal "Stroke," Donald Likosky, Ph.D., and colleagues note that approximately 1 to 4 percent of people undergoing CABG surgery experience a procedure-related stroke, most commonly during the first postoperative day. A blood clot traveling to one of the arteries supplying the brain causes the majority of post-CABG strokes, notes Likosky.
A 2001 study reported by Dr. Sotiris Stamou and colleagues in the journal "Stroke" notes that factors associated with an increased risk for CABG-related stroke include chronic kidney disease, recent heart attack, previous stroke, high blood pressure, diabetes mellitus, advanced age and certain heart rhythm abnormalities. A stroke associated with cardiac bypass surgery increases the risk for a fatal outcome, notes Stamou.
Acute Kidney Failure
Varying degrees of kidney failure may develop during the postoperative period after CABG. In a 2009 article published in the journal "Blood Purification," Dr. Alina Nicoara and colleagues report that up to 10 percent of patients undergoing CABG develop acute kidney failure. Less than 1 percent, however, require kidney dialysis. Among this small group of patients, the risk for death in the postoperative period increases. Most CABG patients with acute postoperative kidney failure recover their preoperative level of kidney function in the weeks following surgery.
References
- "Circulation"; Clinical Predictors of Major Infections After Cardiac Surgery; Vance G. Fowler, Jr., M.D., M.H.S., et al.; 2005
- "Stroke"; Determination of Etiologic Mechanisms of Strokes Secondary to Coronary Artery Bypass Graft Surgery; Donald S. Likosky, Ph.D., et al.; 2003
- "Stroke"; Stroke After Coronary Artery Bypass Incidence, Predictors, and Clinical Outcome; Sotiris C. Stamou, M.D., Ph.D., et al.; 2001
- "Blood Purification"; Mortality Trends Associated with Acute Renal Failure Requiring Dialysis after CABG Surgery in the United States; Alina Nicoara, M.D., et al.; 2009
- National Heart, Lung and Blood Institute: Coronary Artery Bypass Grafting
