Patient Care

Fondaparinux for Treatment of Heparin-Induced Thrombocytopenia


Clinical question: Is fondaparinux as safe and effective as argatroban and danaparoid in treating heparin-induced thrombocytopenia (HIT)?

Background: Guidelines for the treatment of HIT recommend using danaparoid (factor Xa inhibitor), argatroban, or lepirudin (both direct thrombin inhibitors). Reduced availability, cost, and complexity of administration limit these options, and fondaparinux is often used off label in the treatment of HIT.

Study design: Retrospective cohort study.

Setting: London Health Sciences Centre, Ontario, Canada.

Synopsis: Investigators analyzed 133 patients receiving fondaparinux for HIT against unmatched (n=106) and matched (n=60) cohorts receiving either argatroban or danaparoid. Using a composite of new thrombotic events, amputation, gangrene, thrombosis-related death, or death in which thrombosis cannot be excluded as the primary outcome, there was no difference between fondaparinux (16.5%) and the unmatched (19.8%) or matched (16.5%) cohorts of argatroban/danaparoid.

There also was no difference in major bleeding events between fondaparinux (21.1%) and the unmatched (25.5%) and matched (20.0%) argatroban/danaparoid cohorts, though major bleeding rates in this group were higher than in other studies, possibly reflecting a greater proportion of patients with renal dysfunction.

The single-site study was underpowered, and generalizability is limited, as the authors could not review all potential patient files. The risk of confounding effects is increased in the absence of randomization and universal gold standard confirmatory testing among the cohort. Prospective trials are needed to establish the safety and efficacy of treating HIT with fondaparinux.

Bottom line: In this underpowered and retrospective cohort study, fondaparinux was as effective in treating HIT as argatroban and danaparoid, with a similar safety profile.

Citation: Kang M, Alahmadi M, Sawh S, Kovacs MJ, Lazo-Langner A. Fondaparinux for the treatment of suspected heparin-induced thrombocytopenia: a propensity score-matched study. Blood. 2015;125(6):924-929.

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