CHADS score

Periprocedural Anticoagulation Management of Patients With Nonvalvular Atrial Fibrillation
WALDEMAR E. WYSOKINSKI, MD; ROBERT D. MCBANE, MD; PAUL R. DANIELS, MD; SCOTT C. LITIN, MD; DAVID O. HODGE, MS; NICOLE F. DOWLING, PHD; AND JOHN A. HEIT, MD
OBJECTIVE: To estimate the 3-month cumulative incidence of thromboembolism (TE), bleeding, and death among consecutive patients with nonvalvular atrial fibrillation (AF) who were receiving long-term anticoagulation therapy and were referred to the Thrombophilia Center at Mayo Clinic for periprocedural anticoagulation management.
PATIENTS AND METHODS: In a prospective cohort study of consecutive patients receiving long-term anticoagulation therapy who were referred to the Thrombophilia Center for periprocedural anticoagulation management over the 7-year period, January 1, 1997, to December 31, 2003, 345 patients with nonvalvular AF were eligible for inclusion. Warfarin was stopped 4 to 5 days before and was restarted after surgery as soon as hemostasis was assured. The decision to provide bridging therapy with heparin was individualized and based on the estimated risks of TE and bleeding.
RESULTS: The 345 patients with AF (mean ± SD age, 74±9 years; 33% women) underwent 386 procedures. Warfarin administration was not interrupted for 44 procedures. Periprocedural heparin was provided for 204 procedures. Patients receiving heparin were more likely to have prior TE (43% vs 24%; P<.001) and a higher CHADS2 (congestive heart failure, hypertension, age, diabetes, stroke) score (2.2 vs 1.9; P=.06). Four patients had 6 episodes of TE (3 strokes and 3 acute coronary episodes; TE rate, 1.1%; 95% confidence interval, 0.0%-2.1%). Nine patients had 10 major bleeding events (major bleeding rate, 2.7%; 95% confidence interval, 1.0%-4.4%). There were no deaths. Neither bleeding nor TE rates differed by anticoagulant management strategy. CONCLUSION: The 3-month cumulative incidence of TE and bleeding among patients with AF in whom anticoagulation was temporarily interrupted for an invasive procedure was low and was not significantly influenced by bridging therapy. Mayo Clin Proc. 2008;83(6):639-645

Comment by Joel Hernández

The idea of this study was to determine if patients anticoagulated for non-valvular AF that were going to be summited to surgical or invasive diagnostic procedures could de left without anticoagulation, or if it´s necessary to either continue oral anticoagulation or to "bridge" from oral anticoagulation to low-molecular-weight-heparin (LMWH) or non-fractioned-heparin (NFH). This was investigated because it is considered that the risk of emboly is not very high when anticoagulation is suspended for a few days, while, on the other hand, the risk of important hemorrage elevates importantly when it´s not suspended. Some patients were left anticoagulated with Warfarin (an oral anticoagulant like Sintrom) or with heparin (either LMWH or NFH), and some were left without anticoagulation. The decision of whether to anticoagulate or not was done taking into account every patient´s risk of having an emboly and the type of procedure. The conclusion was that the incidence of embolic and hemorragic events in both groups was low and there were no statistically significant differences in these two parameters between both groups. It wasn´t an experimental study, so results must be interpreted cautiously. What´s most important is that the low rates of hemorrage and emboly were probably due to an accurate determination of every patient´s risk, for which the "CHADS index" was used. C (congestive heart failure), H (hypertension), A (age; >75), D (diabetes), S (previous stroke). With 3 or more of these, a patient is considered at high risk for embolic events.