Atrial fibrillation after coronary bypass: etiology and pharmacologic prevention.

Coronary bypass surgery is performed on over 400,000 patients each year in the United States. Atrial Fibrillation (AF) is the most common complication after bypass surgery. The significance of its occurrence lies not only in the potentially dangerous and physiologic derangement to patients, but also in the impact it has on the utilization of health care resources. Several clinical observations suggest that the occurrence of atrial fibrillation after bypass surgery has some unique features related to the perioperative circumstances. Numerous therapies, both pharmacologic and non-pharmacologic have been tested to prevent this tenacious problem. Its persistence continues to intrigue cardio-thoracic surgeons, cardiologists, anesthesiologists and the insurers alike. In this review we discuss the published literature on postbypass AF, with a special emphasis on pharmacologic prevention.

How safely and for how long can warfarin therapy be withheld in prosthetic heart valve patients hospitalized with a major hemorrhage?

STUDY OBJECTIVES: To identify the risk of thromboembolism after withholding or reversing the effect of warfarin therapy following a major hemorrhage. DESIGN: Retrospective medical record review. SETTING: Tertiary-care hospital. PATIENTS: Twenty-eight patients with prosthetic heart valves receiving warfarin were hospitalized for major hemorrhage from 1990 to 1997. The mean +/- SD age was 61 +/- 11 years (15 men and 13 women). Twenty patients had St. Jude valves, 4 patients had Carpentier-Edwards bioprosthetic valves, 2 patients had Starr Edwards valves, and 2 patients had Bjork-Shiley valves. Valves were in the mitral position in 12 patients, the aortic position in 12 patients, and both mitral and aortic positions in 4 patients. The average interval from valve surgery to index bleeding was 7 years. Twenty-five patients had GI or retroperitoneal hemorrhage, 2 patients had an intracranial hemorrhage, and 1 patient had a subdural hematoma. INTERVENTIONS: Vitamin K was administered to five patients and fresh frozen plasma was given to seven patients to reverse anticoagulation. The mean duration of anticoagulation withholding was 15 +/- 4 days. MEASUREMENTS AND RESULTS: None of the patients had thromboembolic complications. There were four in-hospital deaths. Twenty-two of the 24 hospital survivors resumed warfarin therapy at hospital discharge. At 6-month follow-up, 10 of 19 patients remaining on warfarin therapy had recurrent GI bleeding. CONCLUSIONS: Thromboembolic risk is low in prosthetic heart valve patients hospitalized with major hemorrhage when their warfarin therapy is reversed or withheld. Recurrent bleeding within 6 months of the resumption of anticoagulation is common, and aggressive treatment of the bleeding source and the risk-benefit ratio of continued anticoagulation need to be considered.