Drug eluting stents

Gershlick[1] highlights the high morbidity and mortality of late drug
eluting stent thrombosis, particularly associated with premature cessation
of clopidogrel therapy to reduce the risk of bleeding from procedures.
Glycoprotein (GP) IIb/IIIa antagonist use in cardiology patients, in
combination with aspirin, clopidogrel and heparin, has increased markedly
in the acute setting, particularly in those receiving percutaneous
intervention (PCI). Adjusted registry data suggest that they increase the
risk of bleeding at least twofold in these patients, particularly when
combined with heparin.[2]

Both heparin and GP IIb/IIIa antagonists can cause thrombocytopaenia
and increase the risk of mucosal, gastrointestinal and intracranial
bleeding. The reported incidence of thrombocytopaenia associated with GP
IIb/IIIa antagonists varies depending on the agent and platelet definition
used. However, its presence is associated with an increase in severe
bleeding, a higher risk of recurrent myocardial infarction, a greater
transfusion requirement, and an increased 30-day[3] and one-year risk of
death.[4] Platelet transfusion with heparin-induced thrombocytopaenia
(HIT) is contraindicated and markedly increases the risk of thrombosis.
Conversion to a heparinoid with immune-modulatory therapy may improve the
platelet count. Premature platelet transfusion with GP IIb/IIIa antagonist
-induced thrombocytopaenia may also contribute to stent thrombosis.

Combined aspirin and clopidogrel therapy alone increases the risk of
adverse events from bleeding, including upper gastrointestinal.[5]
However, continuation of clopidogrel maybe recommended in the latter if it
occurs soon after PCI, with a high dose 72 hour proton pump inhibitor
infusion, on a case by case basis in the context of non-variceal
gastrointestinal bleeding, with appropriate maintenance of blood pressure
using blood product and fluid support, in close consultation with a
haematologist.

[1] Gershlick AH, Richardson G. Drug eluting stents. BMJ
2006;333:1233-4.

[2] Horwitz PA, Berlin JA, Sauer WH, Laskey WK, Krone RJ, Kimmel SE.
Bleeding risk of platelet glycoprotein IIb/IIIa receptor antagonists in
broad-based practice (results from the Society for Cardiac Angiography and
Interventions Registry). Am J Cardiol 2003;91:803-6.

[3] Merlini PA, Rossi M, Menozzi A, Buratti S, Brennan DM, Moliterno
DJ, Topol EJ, Ardissino D. Thrombocytopenia caused by abciximab or
tirofiban and its association with clinical outcome in patients undergoing
coronary stenting. Circulation 2004;109:2203-6.

[4] Scirica BM, Cannon CP, Cooper R, Aster RH, Brassard J, McCabe CH,
Charlesworth A, Skene AM, Braunwald E. Drug-induced thrombocytopenia and
thrombosis: Evidence from patients receiving an oral glycoprotein IIb/IIIa
inhibitor in the Orbofiban in Patients with Unstable coronary Syndromes-
(OPUS-TIMI 16) trial. J Thromb Thrombolysis 2006;22:95-102.

[5] Jesper Hallas, Michael Dall, Alin Andries, Birthe Søgaard
Andersen, Claus Aalykke, Jane Møller Hansen, Morten Andersen, Annmarie
Touborg Lassen. Use of single and combined antithrombotic therapy and risk
of serious upper gastrointestinal bleeding: population based case-control
study. BMJ 2006;333:726-28.

Competing interests:
None declared