In atrial fibrillation (AF) patients who must discontinue dabigatran for elective surgery, the risk of both stroke and major bleeding can be reduced to very low levels using a formalized strategy for stopping and then re-starting anticoagulation, according to results of a prospective study.

Among key findings presented at a press conference at the ISTH 2015 Congress on Tuesday, no strokes were recorded in more than 500 patients managed with the protocol, and the major bleeding rate was less than 2%, reported the study’s principal investigator, Sam Schulman, professor in the Division of Hematology and Thromboembolism, McMaster University, Hamilton, Canada.

Data from this study, which are being presented in full on Wednesday morning (OR282) and are available online (Schulman S et al. Circulation 2015; epub ahead of print May 12), were reported at the press conference alongside a second study of perioperative warfarin management. Both studies are potentially practice changing, because they supply evidence-based guidance for anticoagulation in patients with AF.

Based on the findings from these two studies, “it is important to get this message out” that there are now data available on which to base clinical decisions, reported Schulman, who is also president of the ISTH 2015 Congress. His data were presented alongside a study that found no benefit from heparin bridging in AF patients when warfarin was stopped 5 days in advance of surgery.

In the study presented by Schulman, 542 patients with AF who were on dabigatran and scheduled for elective surgery were managed on a prespecified protocol for risk assessment. The protocol provided a time for stopping dabigatran before surgery based on such factors as renal function and procedure-related bleeding risk. Dabigatran was restarted after surgery on prespecified measures of surgery complexity and severity of consequences if bleeding occurred.

The primary outcome evaluated in the study was major bleeding in the first 30 days. Other outcomes of interest included thromboembolic complications, death and minor bleeding.

Major bleeding was observed in 1.8% of patients, a rate that Schulman characterized as “low and acceptable” in the context of expected background bleeding rates. There were four deaths, but all were unrelated to either bleeding or arterial thromboembolism. The only thromboembolic complication was a single transient ischemic attack (TIA). Minor bleeding occurred in 5.2%.

On the basis of the protocol, about half of the patients discontinued dabigatran 24 hours before surgery. No patient discontinued therapy more than 96 hours prior to surgery. The median time to resumption of dabigatran after surgery was 1 day, but the point at which it was restarted ranged between hours and 2 days. Bridging, which describes the injection of heparin for short-term anticoagulation, was not employed preoperatively but was used in 1.7% of cases postoperatively.

At the press conference, data also were reported from the BRIDGE study, which was presented as a latebreaker earlier in the week (LB002). That study, summarized earlier in the ISTH Daily News and published online in the New England Journal of Medicine (Douketis et al. epub ahead of print June 22), found that bridging was not an effective strategy in AF patients who discontinue warfarin prior to elective surgery. In the press conference, Thomas L. Ortel, Hematology/Oncology Division, Duke University Medical Center, Durham, North Carolina, U.S.A., agreed with Schulman that this is an area where evidence is needed to guide care.

In the absence of data, “physicians do whatever they think is best,” Schulman noted at the press conference. Referring to strategies for stopping anticoagulants for surgery in patients with AF, Schulman said, “some of them stop the blood thinner too early because they are afraid that the patient is going to bleed during surgery and instead the patient can have a stroke. Some stop too late, and the patient can have bleeding.”

The data presented at the meeting provide an evidence base for clinical decisions. Schulman suggested that these data are meaningful for guiding care.

By Ted Bosworth |June 23, 2015