Info

15 (46)

0.6:1c

4 (22)

aIn seven patients, 17 thrombotic events occurred.

bPrecise number of arterial and venous events is unclear from the published data. For this analysis, of six limb amputations associated with intravascular catheters or devices, five were assumed to be arterial and one venous, based on the type of intravascular catheter or device associated with the amputated limb. cTwo events (encephalopathy and quadriplegia) were not classified. Abbreviation: HIT, heparin-induced thrombocytopenia.

aIn seven patients, 17 thrombotic events occurred.

bPrecise number of arterial and venous events is unclear from the published data. For this analysis, of six limb amputations associated with intravascular catheters or devices, five were assumed to be arterial and one venous, based on the type of intravascular catheter or device associated with the amputated limb. cTwo events (encephalopathy and quadriplegia) were not classified. Abbreviation: HIT, heparin-induced thrombocytopenia.

Overall, frequency of antibody formation was similar in the 2 patient groups, using a commercial EIA that detects IgM, IgA, and IgG antibodies. This is consistent with "point immunization" from intraoperative UHF use, rather than any major influence from postoperative UFH or LMWH. The studies from this group also show that detectability of platelet-activating antibodies (by SRA) is far more predictive of thrombocytopenia than a positive anti-PF4/heparin EIA. Thus, in summary:

1. The frequency of HIT antibody formation following heart surgery is influenced primarily by UFH given at CPB, rather than the type of heparin preparation given postoperatively.

2. Among patients who form HIT antibodies following heart surgery, the risk of HIT likely is higher among those receiving postoperative UFH compared with LMWH.

3. The study indicates a greater clinical usefulness of the SRA, compared with the anti-PF4-heparin EIA (see Chapter 10).

The potential to reduce risk of "breakthrough" of HIT among postcardiac surgery patients who form HIT antibodies is a major reason why antithrombotic agents with low (danaparoid) or negligible (fondaparinux) cross-reactivity against PF4-heparin might be ideal anticoagulants for this clinical situation (Warkentin et al., 2005b) (see Chapter 7).

0 0

Post a comment