The CHADS score role in managing anticoagulation after surgical ablation for atrial fibrillation.

BACKGROUND: Managing anticoagulation after surgical ablation is challenging, especially when sinus rhythm has been restored and the left atrial appendage has been surgically managed. The study purpose was to examine the applicability of the CHADS(2) in determining anticoagulation strategies after surgical ablation. CHADS(2) is a scoring system (0 to 6) used to indicate a patient's risk for a thromboembolic stroke and used for anticoagulation strategies. One point is given for any of the following conditions: C, congestive heart failure; H, hypertension; A, age 75 years old or greater; D, diabetes mellitus; and S, stroke which receives 2 points. A score of 2 or greater is an indication for a patient to be placed on warfarin unless otherwise contraindicated.

METHODS: A prospective, longitudinally designed study where CHADS(2) was calculated for all patients (n = 385). Clinical data on rhythm, anticoagulation medication, bleeding, and embolic stroke-transient ischemic attack (TIA) was obtained every 3 months. Logistic regression models were used to determine significant predictors of either event.

RESULTS: Of the 385 patients, 17% presented with a history of stroke-TIA. In a mean follow-up of 32.77 ± 16.33 months, embolic stroke-TIA events occurred in 4 patients (4.2 first events per 1,000 patient years) and bleeding events occurred in 69 patients (72.8 first events per 1,000 patient years). There was no significant difference in mean CHADS(2) between the stroke event and nonevent group (0.75 vs 1.46, respectively; p = 0.21), but there was a significant difference in CHADS(2) between the major bleed event group and the nonevent group (2.31 vs 1.41, respectively; p < 0.003). The logistic regression model was not predictive of stroke-TIA, but was significantly predictive of bleeding events (χ(2) = 10.30, p < 0.02).

CONCLUSIONS: The number of thromboembolic events after surgical ablation procedure is low and appears unrelated to the CHADS(2). This, together with the higher rate of bleeding, raises questions regarding the applicability of the CHADS(2) for patients after surgical ablation. A randomized study is required to define the risks and anticoagulation strategies for patients after surgical ablation.