NEW YORK (Reuters Health) – Heparin bridging while withholding warfarin before implantation of a heart rhythm device substantially increases the risk of bleeding, new research shows.
By contrast, the bleeding risk was no different between patients maintained on warfarin with an international normalized ratio (INR) of 1.5 or higher and patients who had warfarin withheld until the INR was normal.
Aspirin plus clopidogrel, but not aspirin alone, significantly increased bleeding risk, but to a much smaller extent than heparin.
“Our findings suggest that patients at greatest risk for thromboembolic events off anticoagulation therapy can be safely continued on warfarin rather than transitioning to heparin, whereas patients at low risk should have warfarin held without instituting heparin ‘bridging,’’’ said Dr. Charles A. Henrikson and colleagues from Johns Hopkins Hospital in Baltimore.
They made a similar recommendation for dual antiplatelet therapy, though they emphasize the danger of thrombosis in patients with coronary stents.
Their conclusions are based on a review of bleeding complications in 1388 patients who had pacemaker or implantable cardioverter-defibrillator devices (ICD) implanted at their hospital.
In their May 25th article in the Journal of the American College of Cardiology, they stratify patients by periprocedural anticoagulant or antiplatelet strategy: aspirin plus clopidogrel (n = 139), aspirin only (n = 536), warfarin with an INR < 1.5 (n = 258), warfarin with an INR of 1.5 or higher (n = 46), heparin (n = 154), and no antiplatelet or anticoagulant medications (n = 255).
The authors defined significant bleeding complications – the primary end point -- as need for pocket exploration or blood transfusion, hematoma requiring pressure dressing or change in anticoagulation therapy, or prolonged hospitalization.
Seventy-one patients (5.1%) met the primary endpoint. Complication rates were 14.8% with heparin, 7.2% with aspirin plus clopidogrel, 6.5% with warfarin and an INR of 1.5 or more, 4.3% with warfarin and an INR < 1.5, 3.9% on aspirin only, and 1.6% without antiplatelets or anticoagulants.
On multivariate analysis, bleeding complications were associated with dual antiplatelet therapy (odds ratio 3.84, p = 0.04) or heparin (OR 9.88, p < 0.001). Other predictors of bleeding were male sex (OR 2.51, p = 0.005) and longer procedure time (OR 1.04 per 10-minute intervals, p = 0.006). Being overweight (OR 0.97, p = 0.001) and of African-American race (OR 0.5, p = 0.025) were protective.
The authors note that warfarin increased the risk of bleeding when compared with controls, but the risk was substantially less than with heparin, even when the INR was 1.5 or higher.
Study limitations include its retrospective observational design, small sample size, and lack of a uniform protocol for antiplatelet and anticoagulant management.
But in the end, Dr. Henrikson and colleagues say, “The use of heparin around the time of device implantation is clearly the strongest risk factor for the development of bleeding complications.”
J Am Coll Cardiol 2010;55:2376-2382.