Coronary artery disease
Impact of Baseline Platelet Count in Patients Undergoing Primary Percutaneous Coronary Intervention in Acute Myocardial Infarction (from the CADILLAC Trial)

https://doi.org/10.1016/j.amjcard.2006.11.066Get rights and content

Despite the well-recognized role of platelets in the pathogenesis of acute myocardial infarction (AMI) and in the vascular responses to angioplasty, the relation between platelet count and outcomes after primary percutaneous coronary intervention (PCI) in AMI is unknown. We therefore determined the effect of baseline platelet count on clinical and angiographic outcomes of patients with AMI undergoing primary PCI. In the prospective, randomized CADILLAC trial, platelet count on admission was available in 2,021 of 2,082 patients (97.0%). Angiographic results and outcomes at 30 days and 1 year were stratified by quartiles of platelet count. Median platelet count was 231 × 109/L (range 38 to 709). Primary PCI angiographic success rates were independent of platelet count. The 30-day incidence of target vessel thrombosis or reocclusion increased steadily across the higher quartiles of baseline platelet count (0.2%, 0.6%, 1.0%, and 2.0%, p = 0.027). At 1 year, patients with a baseline platelet count ≥234 versus <234 × 109/L had higher rates of death or reinfarction (8.9% vs 4.5%, p <0.0001), death (5.8% vs 3.1%, p = 0.002), and reinfarction (3.4% vs 1.6%, p = 0.008). By multivariable analysis, a higher baseline platelet count was the strongest predictor of 1-year death or reinfarction (hazard ratio [HR] per 10,000 increase in platelet count 1.02, 95% confidence interval [CI] 1.02 to 1.07, p <0.0001) and independently predicted reinfarction (HR 1.06, 95% CI 1.02 to 1.09, p = 0.002) and cardiac mortality (HR 1.03, 95% CI 1.00 to 1.06, p = 0.055) at 1 year. In conclusion, a higher baseline platelet count in patients with AMI is a powerful independent predictor of death and reinfarction within the first year after primary PCI.

Section snippets

Patient population and treatments

Full details of the CADILLAC protocol have been previously reported.7 Briefly, 2,082 patients of any age with AMI within 12 hours of onset who underwent primary PCI and eligible for stent implantation were randomized in a 2 × 2 factorial design to 1 of 4 mechanical reperfusion strategies: balloon angioplasty with/without abciximab versus stenting with the Multilink stent (Guidant Corp., Santa Clara, California) with/without abciximab. Major exclusion criteria were cardiogenic shock,

Baseline characteristics

Baseline platelet count on admission was available in 2,021 of 2,082 randomized patients (97.0%; Figure 1). Mean ± SD baseline platelet count was 238 ± 66.4 × 109/L (range 38 to 709), and median platelet count (interquartile range) was 231 × 109/L (193 to 274). As presented in Table 1, patients in the higher quartiles were younger, more frequently were women and current smokers, were less likely to have renal insufficiency, previous MI, PCI, and coronary bypass surgery, had higher baseline WBC

Discussion

The present study, to our knowledge the first investigation of the effect of quantitative platelet count in patients undergoing primary PCI, demonstrates that, although procedural success rates are independent of platelet amount, a higher baseline platelet count is a significant and independent predictor of early reinfarction and of late death and reinfarction after primary PCI in patients with AMI.

Reinfarction after primary PCI is uncommon. In the pooled analysis from 7 Primary Angioplasty in

References (30)

  • V. Fuster et al.

    The pathogenesis of coronary artery disease and the acute coronary syndromes

    N Engl J Med

    (1992)
  • C.K. Wong et al.

    Relation of initial platelet counts to Thrombolysis In Myocardial Infarction-3 flow rates at 90 minutes after commencing fibrinolytic therapy in patients with acute myocardial infarction

    Am J Cardiol

    (2002)
  • M.P. Turakhia et al.

    Association of platelet count with residual thrombus in the myocardial infarct-related coronary artery among patients treated with fibrinolytic therapy for ST-segment elevation acute myocardial infarction

    Am J Cardiol

    (2004)
  • H.Q. Ly et al.

    Association of platelet counts on presentation and clinical outcomes in ST-elevation myocardial infarction (from the TIMI Trials)

    Am J Cardiol

    (2006)
  • P.M. Steele et al.

    Balloon angioplastyNatural history of the pathophysiological response to injury in a pig model

    Circ Res

    (1985)
  • Y. Merhi et al.

    Increase of neutrophil adhesion and vasoconstriction with platelet deposition after deep arterial injury by angioplasty

    Am Heart J

    (1995)
  • G.W. Stone et al.

    Comparison of angioplasty with stenting, with or without abciximab, in acute myocardial infarctionThe Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) Investigators

    N Engl J Med

    (2002)

  • Nutritional Anemias: Report of a WHO Scientific Group

    (1968)
  • C. Contal et al.

    An application of changepoint methods in studying the effect of age on survival in breast cancer

    Comput Stat Data Anal

    (1999)
  • S.J. Kernis et al.

    The incidence, predictors, and outcomes of early reinfarction after primary angioplasty for acute myocardial infarction

    J Am Coll Cardiol

    (2003)
  • E.M. Ohman et al.

    An analysis of the cause of early mortality after administration of thrombolytic therapyThe Thrombolysis Angioplasty in Myocardial Infarction Study Group

    Coron Artery Dis

    (1993)
  • A. Halkin et al.

    Prognostic implications of creatine kinase elevation after primary percutaneous coronary intervention for acute myocardial infarction

    J Am Coll Cardiol

    (2006)
  • B.J. Bain

    Platelet count and platelet size in males and females

    Scand J Haematol

    (1985)
  • R. Malacrida et al.

    A comparison of the early outcome of acute myocardial infarction in women and men

    N Engl J Med

    (1998)
  • V. Vaccarino et al.

    Long-term outcome of myocardial infarction in women and men: a population perspective

    Am J Epidemiol

    (2000)

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