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11-12-2011 | Cardiology | Article

Premature heparin re-initiation during bridging therapy puts patients at risk

Abstract

Free abstract

MedWire News: Premature re-initiation of therapeutic heparin within 24 hours of surgery is an independent risk factor for a major bleeding event among chronically anticoagulated patients requiring temporary warfarin interruption for invasive procedures, show study findings.

"In our current practice, we have restructured our post-procedural heparin strategy such that therapeutic heparin (either unfractionated heparin or low-molecular-weight heparin [LMWH]) are held for 48 hours to allow adequate hemostasis following the invasive procedure," say Robert McBane (Mayo Clinic, Rochester, Minnesota, USA) and colleagues.

McBane and team followed up 2182 patients (average age 66 years) who were referred to the Mayo Clinic Thrombophilia Center for periprocedural anticoagulation management during 1997-2007.

The 3-month cumulative incidence of periprocedural bleeding and potential predictors for bleeding were determined.

Decisions to "bridge" therapy with LMWH were based on estimated thromboembolism and bleeding risk.

Of the 2182 patients, 1496 (69%) received bridging therapy with LMWH. Indications for chronic anticoagulation management included venous thromboembolism (38%), atrial fibrillation (30%), and mechanical heart valves (27%). Post-procedural heparin use did not differ according to surgical risk.

At 3 months of follow-up, the overall bleeding rate was 5% and the major bleeding rate was 2%. Compared with patients who received periprocedural heparin, those who did not receive it had a lower overall bleeding rate (3% vs 6%) and major hemorrhage rate (1% vs 3%).

Of the 1714 patients who used heparin, 967 resumed heparin at 24 hours, 210 resumed heparin at 48 hours after surgery, and the rest resumed it at a later date. In total, 27 patients experienced a major bleeding event, which occurred only among patients who resumed heparin within 24 hours of surgery.

Multivariate analysis revealed that independent predictors for major bleeding included mitral mechanical heart valve (hazard ratio [HR]=2.2), prior bleeding history (HR=2.6), and re-initiation of heparin therapy within 24 hours of the procedure (HR=1.9). Aspirin use was not associated with major bleeding.

Further analysis showed that independent predictors of major bleeding specific to patients who received heparin bridging therapy included mitral mechanical heart valve (HR=2.4), undergoing a "moderate-high risk" procedure (HR=1.9), active cancer (HR=1.9), thrombocytopenia less than 150,000 (HR=2.3), and a history of bleeding (HR=2.1).

In light of the findings, the team proposes a scoring system for risk assessment of periprocedural bleeding (BleedMAP) during heparin bridging therapy using the four identified predictors of major bleeding. Patients are assigned to low, intermediate, and high-risk groups, thus providing an estimate of major hemorrhage stratified by bridging strategy.

The findings are published in the Journal of Thrombosis and Haemostasis.

MedWire (http://www.medwire-news.md/) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Ingrid Grasmo

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