Showing papers on "Blood Platelet Disorders published in 2014"

Platelet count and function in paediatric cardiac surgery: a prospective observational study

Abstract: Background Platelet deficiency, impaired platelet function, or both increase the risk of bleeding complications. We assessed platelet count and function during and after paediatric cardiac surgery. Secondary aims included the effect of modified ultrafiltration, identification of factors associated with platelet dysfunction, and to assess associations between platelet function and transfusion requirements. Methods Fifty-seven patients were included in a prospective observational study. Platelet count and platelet function (multiple-electrode impedance aggregometry) were analysed before and during cardiopulmonary bypass (CPB), after modified ultrafiltration, on arrival at the intensive care unit, and on the first postoperative day. Intraoperative transfusions of blood products were registered. Results Both platelet count and platelet aggregation were markedly reduced during surgery with the greatest reduction at the end of CPB. On postoperative day 1, platelet count was still reduced by 50%, while platelet aggregation had returned to—or above—preoperative levels. There were only moderate correlations between platelet count and platelet aggregation. Modified ultrafiltration had no significant influence on platelet count or aggregation. Young age, low weight, and long operation time were associated with poor platelet aggregation during surgery, while young age, low weight, high preoperative haemoglobin levels, and low preoperative platelet count were associated with poor aggregation after operation. Patients with impaired platelet function during CPB had markedly increased intraoperative transfusion requirements. Conclusions Platelet count and platelet aggregation are markedly reduced during and immediately after paediatric cardiac surgery, especially in neonates. The recovery in aggregation is faster than that in platelet count. Intraoperative platelet dysfunction is associated with increased transfusion requirements.

Functional and molecular characterization of inherited platelet disorders in the Iberian Peninsula: results from a collaborative study.

Abstract: The diagnostic evaluation of inherited platelet disorders (IPDs) is complicated and time-consuming, resulting in a relevant number of undiagnosed and incorrectly classified patients. In order to evaluate the spectrum of IPDs in individuals with clinical suspicion of these disorders, and to provide a diagnostic tool to centers not having access to specific platelets studies, we established the project “Functional and Molecular Characterization of Patients with Inherited Platelet Disorders” under the scientific sponsorship of the Spanish Society of Thrombosis and Haemostasis. Subjects were patients from a prospective cohort of individuals referred for clinical suspicion of IPDs as well as healthy controls. Functional studies included light transmission aggregation, flow cytometry, and when indicated, Western-blot analysis of platelet glycoproteins, and clot retraction analysis. Genetic analysis was mainly performed by sequencing of coding regions and proximal regulatory regions of the genes of interest. Of the 70 cases referred for study, we functionally and molecularly characterized 12 patients with Glanzmann Thrombasthenia, 8 patients with Bernard Soulier syndrome, and 8 with other forms of IPDs. Twelve novel mutations were identified among these patients. The systematic study of patients revealed that almost one-third of patients had been previously misdiagnosed. Our study provides a global picture of the current limitations and access to the diagnosis of IPDs, identifies and confirms new genetic variants that cause these disorders, and emphasizes the need of creating reference centers that can help health care providers in the recognition of these defects.

How should we test for nonsevere heritable platelet function disorders

Abstract: Summary Heritable platelet function disorders (HPFD) are a heterogeneous group of bleeding disorders with diverse clinical and laboratory characteristics. In contrast to the severe phenotype disorders, Glanzmann thrombasthenia and Bernard–Soulier syndrome, most nonsevere HPFD are incompletely characterized. This is a consequence of the poor standardization of diagnostic tests and of the lack of consensus about diagnostic criteria for the different subgroups of nonsevere HPFD. Distinguishing patients who have a nonsevere HPFD from those who do not is an essential first step in diagnosis which may be aided by bleeding assessment tools and screening tests such as the Platelet Function Analyser-100. However, high diagnostic accuracy can only be achieved with both light transmission aggregation (LTA) and secretion tests, for which streamlined agonist panels may be of similar utility to extended panels. Standardization of the methodology of these tests and quality assurance are essential for robust diagnosis. Identification of which platelet pathway is defective in patients with nonsevere HPFD is also usually possible with LTA and secretion tests. This strategy also sometimes enables exact diagnosis by implicating a single candidate protein and gene. Next-generation sequencing may offer a rapid approach to diagnosis of nonsevere HPFD, although rigorous strategies must be adopted to distinguish causative gene defects from bystander variations.

A novel method for the management of patients with heparin-induced thrombocytopaenia during cardiac surgery

Abstract: A 63-year old, male patient presented with prosthetic valve endocarditis and developed heparin-induced thrombocytopaenia (HIT) following heparin administration for continuous veno-venous haemofiltration. Use of cardiopulmonary bypass in patients suffering from heparin-induced thrombocytopaenia is difficult and challenging. We report a novel method that allows heparin use in patients diagnosed with HIT using Multiplate platelet analyser and iloprost. Platelet function analysis is complex, poorly standardized and time consuming. Multiplate platelet analyser represents a convenient, safe, reliable and rapid system that allows the assessment of platelet dysfunction. It allows objective demonstration of platelet inhibition before administration of heparin, allowing safe establishment of cardiopulmonary bypass in patients suffering from HIT.

Genetic basis of congenital platelet disorders

Abstract: Over the past 4 decades, a better understanding of the genetic origins of inherited platelet disorders has illuminated avenues of investigation in megakaryopoiesis and has identified targets of pharmacologic intervention. Many of these discoveries have been translated into clinical medicine. The success of inherited platelet disorder research is underpinned by broader advances in methodology through the biochemical and molecular revolution of the 20(th) and 21(st) centuries, respectively. Recently, modern genomics techniques have affected platelet and platelet disorders research, allowing for the discovery of several genes involved in platelet production and function and for a deeper understanding of the RNA and miRNA networks that govern platelet function. In this short review, we focus on recent developments in the genetic elucidation of several disorders of platelet number and in the molecular architecture that determines the "genetic makeup" of a platelet in health and disease.

Deviation from Normal Values of Leukocyte and Erythroblast Parameters in Complete Blood Count is a Messenger for Platelet Abnormalities

Abstract: Automated blood cell counters have undergone a formidable technological evolution owing to the introduction of new physical principles for cellular analysis and the progressive evolution of software [1,2]. The results have been an improvement in analytical efficiency and an increase in information provided with new parameters. A 61-year-old male patient had the diagnosis of diffuse large B-cell lymphoma 6 years ago, and after chemotherapy, he was still in remission. He was hospitalized for high fever, fatigue, acute renal failure, and bibasilar crepitant rales. Complete blood count measured with a Beckman Coulter LH 780 hematology analyzer revealed an uncorrected leukocyte count (UWBC) of 63.5x109/L, leukocyte count (WBC) of 22.1x109/L, erythroblast count (NRBC) of 21.4x109/L, and platelet count of 197x109/L (Figure 1). Upon peripheral blood smear examination, we detected 5% neutrophils, 22% band forms, 61% metamyelocytes, 5% myelocytes, 1% promyelocytes, 2% myeloblasts, 2% lymphocytes, and 2% eosinophils. We also detected rare erythroblasts and large platelets with profuse platelet clumps (Figures 2 ). Routine biochemical analysis revealed high fasting glucose, blood urea nitrogen, creatinine, serum glutamic oxaloacetic transaminase, alkaline phosphatase, direct and indirect bilirubin, albumin, and lactate dehydrogenase. The erythrocyte sedimentation rate was 100 mm/h, and serum ferritin was 2944 ng/mL. High-resolution computed tomography of the thorax revealed bilateral diffuse infiltrations, nodular opacities, right pleural effusion, and mediastinal lymphadenopathies. Clarithromycin and imipenem/cilastatin were administered for a probable diagnosis of pneumonia. Bone marrow examination revealed myeloid hyperplasia but nothing else significant. No endobronchial mass was detected in bronchoscopy, but mucopurulent secretion was present in the right upper and lower lobes. Biopsy reports showed non-neoplastic bronchial mucosa epithelium. Sputum, blood, and urine cultures; sputum mycobacterial examination; and serum galactomannan antigen were all negative. After the general condition, fever, acute renal failure, signs, and symptoms were relieved, the patient was discharged. Informed consent was obtained. Figure 1 Complete blood count. Figure 2 Peripheral smear. Large platelets with profuse platelet clumps are noteworthy. When we subtracted the WBC and NRBC from the UWBC (=20.0x109/L), a significanT-cell group was composed of big platelets. It is probable that this ratio was higher than calculated. Rare erythroblasts in the peripheral blood smear with high NRBC values support the idea of large platelets as cellular origin. In fact, the peripheral blood smear revealed large, profuse platelet clumps, contradictory to the platelet count. We conclude that complete blood counts should be examined carefully; despite the essential role of automation in the modern hematology laboratory, microscopic control of pathologic samples (i. e. peripheral blood smear) remains indispensable, so much so that in certain cases, it alone is diagnostic.