Patients with previous definite stent thrombosis have a larger fraction of immature platelets and a reduced antiplatelet effect of aspirin

Morten Würtz, Erik Grove, Lise Nielsen Wulff, Anne Kaltoft, Hans-Henrik Tilsted Hansen, Lisette Okkels Jensen, Anne-Mette Hvas, Steen Dalby Kristensen

Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskning

Abstract

Objectives
This study sought to evaluate the platelet response to aspirin and the immature platelet fraction in patients with previous stent thrombosis (ST).

Background
ST is a potentially fatal complication of coronary stenting. A reduced platelet response to aspirin increases the risk of cardiovascular events.

Methods
We included 117 patients previously undergoing percutaneous coronary intervention. A total of 39 patients had suffered ST and 78 patients served as controls matched at a 1:2 ratio with respect to age, sex, stent type, and percutaneous coronary intervention indication. All patients were treated with aspirin 75 mg once daily. Platelet function was assessed by multiple electrode aggregometry in citrated and hirudinized blood and by VerifyNow Aspirin Assay (Accumetrics, San Diego, California). Flow cytometric determination of the immature platelet fraction was performed to evaluate platelet turnover. Platelet activation was evaluated by soluble serum P-selectin. Compliance was confirmed by serum thromboxane B2.

Results
All patients were fully compliant, which was confirmed by suppressed levels of serum thromboxane B2. Platelet aggregation was increased in patients with previous ST when assessed by multiple electrode aggregometry induced by collagen (pcitrated blood = 0.003; phirudinized blood < 0.0001) and by arachidonic acid (pcitrated blood = 0.16; phirudinized blood = 0.04), respectively. Similarly, platelet aggregation assessed by VerifyNow was higher in ST cases (p = 0.12). A trend toward an increased immature platelet fraction among cases was seen (p = 0.13), whereas P-selectin levels (p = 0.56) did not differ between groups.

Conclusions
Overall, patients with previous ST had a reduced antiplatelet effect of aspirin, which might be explained by an increased platelet turnover.

Key Words: aspirin; immature platelets; platelet aggregation; platelet function tests; stent thrombosis

Abbreviations: ARU, aspirin reaction units; AU, aggregation units; BMS, bare-metal stent(s); DES, drug-eluting stent(s); IPF, immature platelet fraction; MEA, multiple electrode aggregometry; PCI, percutaneous coronary intervention; RNA, ribonucleic acid; ST, stent thrombosis; S-TxB2, serum thromboxane B2
OriginalsprogDansk
Publikationsdato2010
Antal sider1
StatusUdgivet - 2010
Udgivet eksterntJa
BegivenhedJournal of the American College of Cardiology - Atlanta
Varighed: 9 mar. 20109 mar. 2010

Konference

KonferenceJournal of the American College of Cardiology
ByAtlanta
Periode09/03/201009/03/2010

Citationsformater