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Continued Warfarin Better Approach to Cardiac Device Surgery.

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Higher-risk patients undergoing cardiac device surgery are better off continuing warfarin than switching to heparin as guidelines recommend, according to a New England Journal of Medicine study.

The study included nearly 700 patients at moderate-to-high risk for thromboembolic events who were taking warfarin and required nonemergency pacemaker or implantable cardioverter-defibrillator surgery. Patients were randomized to either continue warfarin (target INR: 3.0 or less; 3.5 or less for patients with mechanical valves) or receive bridging therapy with heparin as recommended by the American College of Chest Physicians.

The study was stopped early after an interim analysis found that the primary outcome — device-pocket hematoma — had occurred four times as often with heparin as with warfarin (16% vs. 3.5%). Continued warfarin didn’t increase major perioperative bleeding.

One explanation for the “counterintuitive” finding, the authors write, “is the concept of an ‘anticoagulant stress test.’ That is, if patients undergo surgery while receiving full-dose anticoagulation therapy, any excessive bleeding will be detectable and appropriately managed while the wound is still open. In contrast, if bridging therapy with heparin is used, such bleeding may be apparent only when full-dose anticoagulation therapy is resumed postoperatively.”

Source: NEJM 

HAS-BLED for Assessing Bleeding Risk with Anticoagulation: Best of the Mediocre.

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Notwithstanding a lackluster performance, HAS-BLED beat two other scoring systems in a comparative analysis of trial data.

Bleeding continues to be the Achilles heel of systemic anticoagulation, whether the agent used is warfarin or any of the new anticoagulants entering the market. Predictive models for bleeding include the following:

ATRIA (anticoagulation and risk factors in atrial fibrillation)

Investigators for the AMADEUS trial comparing warfarin with idraparinux (JW Gen Med Feb 26 2008) retrospectively applied all three scoring systems to the 2293 patients randomized to the warfarin arm. Although none of the three demonstrated more than modest efficacy in predicting any clinically relevant bleeding (c-index range, 0.50–0.60), HAS-BLED — the simplest to use — outperformed the others, especially with regard to intracranial hemorrhage (c-index, 0.75).

Comment: Although their predictive value is limited, these scoring systems quantify bleeding risk and thus are better than qualitative clinical judgment alone. The simple HAS-BLED model performed better than the others and is a reasonable tool to assess bleeding risk in clinical practice, at least for now.

Source: Journal Watch Cardiology