Decline in platelet count in patients treated by percutaneous coronary intervention: definition, incidence, prognostic importance, and predictive factors.
ABSTRACT We investigated the incidence, predictors, and prognostic impact of a decline in platelet count (DPC) in patients treated by percutaneous coronary intervention (PCI).
A total of 10 146 consecutive patients treated by PCI from 2003 to 2006 were included. According to the magnitude of the DPC, the population was divided into four groups: no DPC (<10%), minor DPC (10-24%), moderate DPC (25-49%), and severe DPC (>or=50%). The primary haemorrhagic endpoint was a composite of post-procedure surgical repair major bleeding. The primary ischaemic endpoint was 30-day all-cause mortality-non-fatal myocardial infarction. Among the total population, 36% had a DPC <10%, 47.7% had a DPC of 10-24%, 14% had a DPC of 25-49%, and 2.3% had a DPC >or=50%. On multivariate analysis, moderate and severe DPC were independent predictive factors of the ischaemic outcome. Two procedural practices were identified that, if modified, might reduce the incidence of acquired thrombocytopaenia. Both the intraprocedural use of heparin (as opposed to bivalirudin) and of low molecular weight contrast material were independently associated with severe acquired thrombocytopaenia.
Moderate and severe DPC are independent predictors of adverse bleeding and ischaemic outcomes in PCI. Adoption of intraprocedural anticoagulant other than heparin and avoidance of a low molecular weight contrast agent could potentially decrease the occurrence of severe acquired thrombocytopaenia.
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ABSTRACT: We performed a prospective, double-blind study of the incidence of thrombocytopenia in 149 patients randomly assigned to treatment with one of three heparin preparations--from bovine lung from intestinal-mucosa A, or from intestinal-mucosa O. Thrombocytopenia developed in 21 patients (platelets, < 100 x 10(9) per liter): 13 of the 50 receiving bovine lung heparin, four of 45 receiving intestinal-mucosa-A heparin, and four of 54 receiving intestinal-musoca-O heparin (P < 0.005). There was a significantly increased incidence of thrombocytopenia in the bovine-lung group (P < 0.002); estimated incidence rates after nine days of treatment were 24 per cent in this group and 7 per cent in the combined intestinal-mucosa A and O groups. Thrombocytopenia appeared in the bovine-lung group on days 3 to 16, in the intestinal-mucosa-A groups on Days 4 to 12, and in the intestinal-mucosa-O group on Days 3 to 7; it disappeared in all groups three to eight days after discontinuation of heparin. A total of 121 patients were subsequently given warfarin for four to six months, and thrombocytopenia was not observed.New England Journal of Medicine 11/1980; 303(16):902-7. · 51.66 Impact Factor
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ABSTRACT: Heparin-induced thrombocytopenia, defined by the presence of heparin-dependent IgG antibodies, typically occurs five or more days after the start of heparin therapy and can be complicated by thrombotic events. The frequency of heparin-induced thrombocytopenia and of heparin-dependent IgG antibodies, as well as the relative risk of each in patients given low-molecular-weight heparin, is unknown. We obtained daily platelet counts in 665 patients in a randomized, double-blind clinical trial comparing unfractionated heparin with low-molecular-weight heparin as prophylaxis after hip surgery. Heparin-induced thrombocytopenia was defined as a decrease in the platelet count below 150,000 per cubic millimeter that began five or more days after the start of heparin therapy, and a positive test for heparin-dependent IgG antibodies. We also tested a representative subgroup of 387 patients for heparin-dependent IgG antibodies regardless of their platelet counts. Heparin-induced thrombocytopenia occurred in 9 of 332 patients who received unfractionated heparin and in none of 333 patients who received low-molecular-weight heparin (2.7 percent vs. 0 percent; P = 0.0018). Eight of the 9 patients with heparin-induced thrombocytopenia also had one or more thrombotic events (venous in 7 and arterial in 1), as compared with 117 of 656 patients without heparin-induced thrombocytopenia (88.9 percent vs. 17.8 percent; odds ratio, 36.9; 95 percent confidence interval, 4.8 to 1638; P < 0.001). In the subgroup of 387 patients, the frequency of heparin-dependent IgG antibodies was higher among patients who received unfractionated heparin (7.8 percent, vs. 2.2 percent among patients who received low-molecular-weight heparin; P = 0.02). Heparin-induced thrombocytopenia, associated thrombotic events, and heparin-dependent IgG antibodies are more common in patients treated with unfractionated heparin than in those treated with low-molecular-weight heparin.New England Journal of Medicine 05/1995; 332(20):1330-5. · 51.66 Impact Factor
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ABSTRACT: Diagnosis of immune heparin-induced thrombocytopenia (HIT) is usually based on a fall in platelet count below 150 x 109/L (standard definition of thrombocytopenia). However, this definition may be inappropriate for postoperative patients who often develop postoperative thrombocytosis. We sought to determine an improved definition of thrombocytopenia indicating HIT in postoperative orthopedic patients, including its impact on frequency and thrombotic risk of HIT. We performed a secondary analysis of a clinical trial of 665 patients who received unfractionated or low-molecular-weight heparin following elective hip arthroplasty. Daily platelet counts and objective studies for deep vein thrombosis were performed in all patients. Laboratory detection of HIT antibodies from a 362-patient subgroup was used to define sensitivity and specificity of various definitions of thrombocytopenia to indicate HIT. The improved definition of HIT was a 50% or greater platelet count fall from the postoperative peak, as this definition had greater sensitivity (50% vs 25%) and similar high specificity (99.1% vs 99.4%) for detecting HIT-IgG compared with the standard definition. Patients with HIT who were identified using the improved definition had a higher frequency of thrombosis than patients without HIT (72.2% vs 17.3%; P<.001). The improved definition showed an even greater absolute difference in frequency of HIT between unfractionated and low-molecular-weight heparin (4.8% vs 0.6%; P<.001) compared with the standard definition (2.7% vs 0%; P =.002). A 50% or greater fall in the platelet count from the postoperative peak is a sensitive definition indicating possible HIT that is associated with an increased risk of thrombosis.Archives of Internal Medicine 12/2003; 163(20):2518-24. · 11.46 Impact Factor