Platelets
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Randomized Controlled Trial Clinical Trial
A prospective randomized trial comparing the recovery of platelet function after loading dose administration of prasugrel or clopidogrel.
Prasugrel results in greater platelet inhibition compared to clopidogrel which may prolong the time to platelet P2Y(12) receptor function recovery following drug cessation after loading dose (LD) administration. This randomized study assessed the time to recovery of platelet function in patients with coronary artery disease after a LD of prasugrel or clopidogrel. Enrolled patients (n = 21) received either prasugrel (30 mg or 60 mg) or clopidogrel (600 mg) in preparation for coronary angiography. Platelet function was assessed by the VerifyNow P2Y12 assay, Multiplate and LTA at baseline and over time (1, 3, 5, 7, 9, and 11 days) post-LD treatment. Recovery of platelet function was defined as occurring on the first day that P2Y12 reaction units were ≤60 below pre-drug values and remained in this range. The relationship between platelet inhibition at 24 h post-LD to time of recovery was also evaluated. Recovery of platelet function occurred from days 3-7 for clopidogrel-treated subjects, by day 7 for patients treated with prasugrel 30 mg and from days 7-9 for patients treated with prasugrel 60 mg. Time for platelet function to return to baseline was independent of treatment assignment, reflecting instead the extent of platelet inhibition at 24 h post-LD (correlation coefficient = 0.81, p < 0.001), which was greater following a prasugrel LD. ⋯ Prasugrel-treated subjects require a longer time for recovery compared with clopidogrel due to greater post-LD platelet inhibition. Platelet function testing after cessation of P2Y(12) receptor blockers may prove useful to guide the timing of surgical procedures (clinicaltrials.gov identifier: NCT01107899).
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Pneumatic tube systems (PTS) present a convenient way for blood sample transport in medical facilities. Associated preanalytical interference in various tests is largely unknown. Implementing point-of-care coagulation management at our institution, we investigated multiple electrode aggregometry (MEA) and rotational thromboelastometry (ROTEM) after PTS transportation. ⋯ PTS transport caused invalid results in MEA while only one ROTEM parameter was found to be affected in this study. Variable acceleration during transport provides a potential reason for platelet activation. The authors recommend sample transport by hand or the device to be placed patient-side when MEA is performed.
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Sickle cell disease (SCD) is characterized by a complex vasculopathy, consisting of endothelial dysfunction and increased arterial stiffness, with a global effect on cardiovascular function. The hypercoagulable state may result from chronic hemolysis and circulating cell-derived microparticles (MPs) originating mainly from activated platelets and erythrocytes. We measured the levels of platelet and erythrocyte-derived MPs (PMPs and ErMPs) in 50 young SCD patients compared with 40 age- and sex-matched healthy controls and assessed their relation to clinicopathological characteristics and aortic elastic properties. ⋯ We suggest that PMPs and ErMPs overproduction may be considered a potential biological marker for vascular dysfunction and disease severity in SCD and may be implicated in the pathogenesis of coagulation abnormalities encountered in those patients. Their levels are closely related to sickling crisis, pulmonary hypertension, markers of hemolysis, fibrinolysis, and iron overload. Therefore, quantification of MPs in SCD may provide utility for identifying patients who are at increased risk of thrombotic events or cardiovascular abnormalities and would help to monitor response to hydroxyurea therapy.
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Heparin-induced thrombocytopenia (HIT) is a potentially lethal adverse effect of heparin therapy. Accurate and rapid HIT laboratory diagnosis when HIT is suspected is crucial. The combination of an immunological assay with a functional test improves the accuracy of HIT, but functional assays are currently limited to a few laboratories. ⋯ Both tests showed a high negative predictive value while HIMEA had a better positive predictive value. HIMEA has overall better performance characteristics than PAT for the detection of HIT platelet-activating antibodies. The combination of an immunological assay with HIMEA could be a feasible option in non-specialized laboratories for HIT diagnosis optimization.
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Familial Mediterranean fever (FMF) is an autosomal recessive hereditary disease which is characterized by recurrent attacks of fever and peritonitis, pleuritis, arthritis, or erysipelas-like skin disease. Mean platelet volume (MPV) is a sign of platelet activation. There are limited studies in the literature about MPV levels in FMF patients. ⋯ The mean platelet count of group 1 was higher than that of group 3 (p = 0.010). In conclusion, this study results suggested that MPV level did not increase on the contrary, it decreased in patients with FMF both in group 1 and/or group 2 when compared to group 3. It was concluded that the lower MPV level was an expected result of secondary thrombocytosis in FMF patients.