The most common complications of coronary bypass surgery include bleeding and heart rhythm irregularities, according to Mayo Clinic. Other less-frequent complications include kidney failure, infections of the surgical site, memory loss and stroke. If a blood clot breaks free after surgery, a heart attack may occur.
Scheduled coronary bypass surgery is less risky for the patient than emergency coronary bypass surgery, notes Mayo Clinic. The patient’s health prior to surgery determines the patient’s individual risk for complications. For example, patients with conditions such as diabetes, kidney disease, emphysema or peripheral artery disease are more likely to experience complications of surgery than those who are in better health.