Platelet-endothelial interactions: sepsis, HIT, and antiphospholipid syndrome

The potential impact of Covid-19 on the capacity of routine laboratory tests to detect heparin-induced thrombocytopenia

In Covid-19, anticoagulation with heparin is often administered to prevent or treat thromboembolic events. Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin treatment, caused by heparin-dependent, platelet activating anti-platelet factor 4 (PF4)/heparin antibodies. Diagnosis of HIT is based on the combination of clinical parameters, allowing to determine the pretest probability, and laboratory testing for anti-PF4/heparin antibodies and confirmatory functional assays, such as the heparin-induced platelet activation (HIPA) test.

We report the case of a patient with severe Covid-19 pneumonia requiring ECMO treatment, who developed recurrent clotting of the ECMO filter and a drop in platelet count under heparin treatment. He was therefore suspected to have HIT and the anticoagulation was switched to argatroban. Despite high clinical probability and high titres of anti-PF4/heparin antibodies, the functional HIPA test was negative. Nevertheless, argatroban was continued rather than to reinstate anticoagulation with heparin. Reevaluation 7 days later then demonstrated a strongly positive functional HIPA test and confirmed the diagnosis of HIT. Under anticoagulation with argatroban the patient gradually improved and was finally weaned off the ECMO.

In conclusion, this case highlights the critical importance of clinical judgement, exploiting the 4 T score, given that Covid-19 patients may present a different pattern of routine laboratory test results in HIT diagnostics. The possibility of a false negative HIPA test has to be considered, particularly in early phases of presentation. In cases of a discrepancy with high clinical probability of HIT and/or high titre anti-PF4/heparin antibodies despite a negative HIPA test, a reevaluation within 3 to 5 days after the initial test should be considered in order to avoid precipitant reestablishment of unfractionated heparin, with potentially fatal consequences.

Thrombocytopenia in chronic liver disease: Physiopathology and new therapeutic strategies before invasive procedures

Chronic liver disease is characterized by several hematological derangements resulting in a complex and barely rebalanced haemostatic environment. Thrombocytopenia is the most common abnormality observed in these patients and recent advances have led to researchers focus the attention on the multifactorial origin of thrombocytopenia and on the key role of thrombopoietin (TPO) in its physiopathology. Severe thrombocytopenia (platelet count < 50000/μL) complicates the management of patients with chronic liver disease by increasing the potential risk of bleeding for invasive procedures, which may be therefore delayed or canceled even if lifesaving. In the very last years, the development of new drugs which exceed the limits of the current standard of care (platelet transfusions, either immediately before or during the procedure) paves the way to a new scenario in the management of this population of patients. Novel agents, such as the TPO-receptor agonists avatrombopag and lusutrombopag, have been developed in order to increase platelet production as an alternative to platelet transfusions. These agents have demonstrated a good profile in terms of efficacy and safety and will hopefully allow reducing limitations and risks associated with platelet transfusion, without any delay in scheduled interventions. Altogether, it is expected that patients with chronic liver disease will be able to face invasive procedures with one more string in their bow.

The Association between Kidney Function and the Severity of COVID-19 in Children

BACKGROUND: Kidney manifestations are life-threatening conditions, such as end-stage kidney disease, notably when caused by viral infections. The severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2), is an emerging global health problem, potentially affecting all organs, including the kidney. Most reports on kidney manifestations were focused on the adult and elderly population but limited on children. AIM: This study aims to analyze the association between kidney function and the severity of the disease of pediatric patients suffering from COVID-19. METHODS: From March 2020 to March 2021, an observational analytic study was conducted in Hasan Sadikin General Hospital, Bandung, Indonesia. The demographic data, clinical signs, laboratory results, and notable kidney function were analyzed, and based on its clinical appearance the disease was classified as severe and non-severe. Subsequently, the Mann–Whitney test for nonparametric was used to analyze the collected data. RESULTS: In this study, 40 COVID-19 children were selected as the subjects, and the median estimated glomerular filtration rate (eGFR) value in the severe group was discovered to be lower (88.2 mL/min/1.73 m2) compared to the non-severe (124.4 mL/min/1.73 m2), it was statistically significant (p = 0.041). There was no difference in hemoglobin and leukocyte values between the two groups (p > 0.05). Furthermore, the CRP and NLR results showed no difference between the groups (p > 0.05). CONCLUSION: A severe SARS-CoV-2 infection correlates with kidney function, which was manifested by a lower median eGFR value in the severe compared to the non-severe group.

What Function Do Platelets Play in Inflammation and Bacterial and Viral Infections?

The article presents the function of platelets in inflammation as well as in bacterial and viral infections, which are the result of their reaction with the endovascular environment, including cells of damaged vascular endothelium and cells of the immune system. This role of platelets is conditioned by biologically active substances present in their granules and in their specific structures - EV (extracellular vesicles).

Coagulopathy in SARS-CoV-2 Infected Patients: Implication for the Management of COVID-19

COVID-19 disease has led to an extraordinary inclusive health crisis globally. Elevation of D-dimer is the major remarkable abnormal coagulation test in seriously ill COVID-19 patients. In nearly 50% of COVID-19 patients, the value of D-dimer was significantly enhancing. Recent literature indicated that COVID-19 patients were at higher risk of developing disseminated intravascular coagulation. Pro-inflammatory cytokines and chemokines are some of the factors leading to these conditions. The majority of COVID-19 patients showed a higher profile of pro-inflammatory cytokines and chemokines in severe clinical conditions. Tumor necrosis factor-α (TNF-α) and interleukins (ILs) elevated in COVID-19 infected patients. TNF-α, IL-6, and IL-1 are major cytokines vital for the inhibition of intrinsic anticoagulant pathways. COVID-19 becomes a higher complication with a significant effect on blood cell production and hemostasis cascades. Deep vein thrombosis and arterial thrombosis are common complications. Changes in hematological parameters are also frequently observed in COVID-19 patients. Especially, thrombocytopenia is an indicator for poor prognosis of the disease and is highly expected and aggravates the likelihood of death of SARS-CoV-2 infected individuals. Thrombopoiesis reduction in COVID-19 patients might be due to viral abuse of the bone marrow/the viral load may affect thrombopoietin production and function. In other ways, immune-inflammation-mediated destruction and increased consumption of platelets are also the possible proposed mechanisms for thrombocytopenia. Therefore, the counting of platelet cells is an easily accessible biomarker for disease monitoring. All SARS-CoV-2 infected patients should be admitted and identifying potential higher-risk patients. It is also obligatory to provide appropriate treatments with intensive care and strict follow-up. In addition, considerations of chronic diseases are essential for better prognosis and recovery. The current review discusses coagulopathy among SARS-CoV-2 infected individuals and its complication for the management of the disease.

Clinically significant anticardiolipin antibodies associated with COVID-19

The novel coronavirus strain known as SARS-CoV-2 has rapidly spread around the world creating distinct challenges to the healthcare workforce. Coagulopathy contributing to significant morbidity in critically ill patients with SARS-CoV-2 has now been well documented. We discuss two cases selected from patients requiring critical care in April 2020 in New York City with a unique clinical course. Both cases reveal significant thrombotic events noted on imaging during their hospital course. Obtaining serial inflammatory markers in conjunction with anti-phospholipid antibody testing revealed clinically significant Antiphospholipid syndrome (APS). This case series reviews the details preceding APS observed in SARS-CoV-2 and aims to report findings that could potentially further our understanding of the disease.

Risk Factors for Myocardial Infarction and Stroke Among Sepsis Survivors: A Competing Risks Analysis

Objectives:

Predictors for post-sepsis myocardial infarction (MI) and stroke are yet to be identified due to the competing risk of death.

Methods:

This study included all hospitalized patients with sepsis from National Health Insurance Research Database of Taiwan between 2000 and 2011. The primary outcome was the first occurrence of MI and stroke requiring hospitalization within 180 days following hospital discharge from the index sepsis episode. The association between predictors and post-sepsis MI and stroke were analyzed using cumulative incidence competing risk model that controlled for the competing risk of death.

Results:

Among 42 316 patients with sepsis, 1012 (2.4%) patients developed MI and stroke within 180 days of hospital discharge. The leading 5 predictors for post-sepsis MI and stroke are prior cerebrovascular diseases (hazard ratio [HR]: 2.02, 95% confidence interval [CI]: 1.74-2.32), intra-abdominal infection (HR: 1.94, 95% CI: 1.71-2.20), previous MI (HR: 1.81, 95% CI: 1.53-2.15), lower respiratory tract infection (HR: 1.62, 95% CI: 1.43-1.85), and septic encephalopathy (HR: 1.61, 95% CI: 1.26-2.06).

Conclusions:

Baseline comorbidities and sources of infection were associated with an increased risk of post-sepsis MI and stroke. The identified risk factors may help physicians select a group of patients with sepsis who may benefit from preventive measures, antiplatelet treatment, and other preventive measures for post-sepsis MI and stroke.

Evaluation of a rapid and automated heparin-induced thrombocytopenia immunoassay

Introduction

Heparin‐induced thrombocytopenia (HIT) is a potentially life‐threatening adverse reaction of heparin. Laboratory evaluation of HIT is often not available within a reasonable time. We evaluated the HemosIL^® HIT‐Ab_(PF4‐H) (Instrumentation Laboratory), a rapid, on‐demand, fully automated, latex immunoturbidimetric assay (LIA).

Materials and methods

Following determination of the LIA's reference interval and cutoff values, a multicenter study was conducted between March 2013 and June 2015. Plasma samples of HIT‐suspected patients (n = 632) were collected and evaluated by LIA on the ACL TOP^® Family systems (Instrumentation Laboratory), enzyme‐linked immunosorbent assays (EIA), and serotonin release assay (SRA). Patient characteristics, medical conditions, comorbidities, laboratory results, and medications were collected via medical chart review. The pretest clinical probability of HIT was also calculated for each patient.

Results

Based on the 95% reference interval for healthy donors and HIT‐negative patients, a LIA value ≥1.0 U/mL was interpreted positive. The overall agreement of LIA versus EIA and SRA results were 90% (95% CI 88%‐92%) and 79% (95% CI 75%‐82%), respectively. The negative predictive value for LIA and EIA was comparable (87%) with SRA. The positive and negative percent agreements with the clinical probability were 89% (95% CI 69%‐97%) and 86% (95% CI 83%‐89%), respectively, with a negative predictive value of 99.6% (95% CI 98%‐100%).

Discussion

Overall, the LIA results were comparable to those of EIA and SRA. This fully automated assay with a remarkable short analytical turnaround time of <20 minutes can be performed on‐demand, which would greatly facilitate more prompt management of HIT.

[Venous thromboembolic complications in oncological patients: present-day possibilities of effective and safe anticoagulant therapy]

Cancer-associated thromboembolic complications in malignant neoplasms are commonly encountered. They deteriorate the course of the underlying disease and are frequent causes of death. The oncological patient is at high risk of not only thrombosis but haemorrhage during anticoagulant therapy. Recent randomized clinical trials have positively appreciated the possibilities of direct oral anticoagulants in treatment and prevention of thromboses in oncological patients. Analysing subgroups in these studies demonstrated that direct oral anticoagulants during long-term administration were at least as effective and safe as vitamin K antagonists. The most significant by the number of cases, duration of therapy, and methodology of analysis are the reports regarding rivaroxaban - an oral, direct factor Xa inhibitor. There are also findings obtained in a separate randomized study, confirming efficacy and safety of rivaroxaban in treatment of patients with cancer-associated venous thromboembolic complications as compared with therapy with low-molecular-weight heparins. Namely these results formed the basis for the guidelines of the International Society on Thrombosis and Hemostasis (SSC ISTH), according to which rivaroxaban may be regarded as an alternative to low-molecular-weight heparins in certain clinical situations.

High prevalence of heparin induced thrombocytopenia with thrombosis among patients with essential thrombocytemia carrying V617F mutation

Arterial and venous complications are major causes of morbidity and mortality in myeloproliferative neoplasms (MPNs). MPNs patients, frequently receive heparin. Heparin-induced thrombocytopenia (HIT) is a rare but potentially life-threatening complication resulting in a severe acquired thrombophilic condition. We carried out a retrospective analysis to evaluate occurrence of new thrombotic events during heparin therapy in essential thrombocythemia (ET) patients. We studied 108 ET patients on heparin for treatment of previous thrombotic events or in thromboprophilaxis. Fifty-eight of them carried JAK 2 V617F mutation while 50 patients were without V617F mutation. Ten patients, among those with JAK 2 V617F mutation after a median of 10 days from heparin treatment presented a platelet drop, new thrombotic events and in 10/10 cases heparin-related antibodies were found. In the other group, two patients (4%) presented a platelet drop, thrombotic manifestations and heparin related antibodies. Our data show that HIT is more frequent, during heparin treatment, in patients with ET carrying V617F mutation, as compared with patients without mutations (P = 0.029). ET with V617F mutation seems to be associated with higher risk of thrombotic complications during heparin treatment. Monitoring platelet counts very closely during the course of heparin is essential especially in ET patients in which platelet drop may be hidden by constitutional thrombocytosis.

An infrequent complication of a not so infrequent disease. Hit by HIT

Heparin-induced thrombocytopenia is not uncommon in cardiac surgery. Thrombosis is the most frequent complication. A 77-year-old man suffered cardiac arrest due to right coronary emboli. Transesophageal echocardiography revealed tissue valve thrombosis. He required support with an extracorporeal membrane oxygenator that also thrombosed. Heparin-induced thrombocytopenia was diagnosed, and anticoagulation was switched to argatroban. Heparin- induced thrombocytopenia normally presents as vascular thrombosis. In this case, the first symptom was tissue valve thrombosis causing an acute coronary syndrome. It is not an uncommon complication and should be considered if unexpected thrombosis and a sudden drop in platelet count develops after heparin exposure.

A case series: Association of anaphylaxis with a significant decrease in platelet levels and possible secondary risk of thrombosis

Introduction

Anaphylaxis is a life threatening systemic inflammatory process that share mediators involved in the coagulation cascade. Platelet activating factor, known to increase platelet aggregation, has also been implicated as an important mediator of anaphylaxis. Although other inflammatory reactions are associated with an increased risk of thrombosis, anaphylaxis is currently not reported as one of them. Furthermore the role platelets may have in the perianaphylaxis period is not well understood. We here in present a retrospective case series of three patients that had platelet aberrations suggestive of PAF involvement and clinically significant thrombosis in close relationship with anaphylaxis.

Objective

To investigate platelet response before and after anaphylaxis and indirect observation evidence of platelet activating factors involvement with possible increased risk of thrombosis.

Methods

A retrospective investigation into medical records including medication administrations times, laboratory, and radiology results. Platelet levels pre‐ and post‐ anaphylaxis were statistically analyzed.

Results

Case 1, a 44 year old man had an anaphylactic reaction shortly after envenomation and subsequently suffered an acute infarction with thrombus in a cerebral artery. Case 2 is a 49 year old man with idiopathic anaphylaxis who developed a deep vein thrombosis after a protracted anaphylaxis event. Case 3 involved an 18 year old female with acute myeloid leukemia was found to have a thrombus in the celiac trunk following anaphylaxis. A paired two‐tailed Wilcoxon test on the subjects pre and post anaphylactic platelet levels resulted in a overall P < 0.0001.

Conclusions and Clinical Relevance

These three cases illustrate the potential role platelets may have in anaphylaxis and possible increased secondary risk for the development of thrombosis. Larger studies are required to determine incidence and risk factors for blood clots following anaphylaxis in order to provide management or screening recommendations.

Blood platelets and sepsis pathophysiology: A new therapeutic prospect in critically [corrected] ill patients?

Beyond haemostasis, platelets have emerged as versatile effectors of the immune response. The contribution of platelets in inflammation, tissue integrity and defence against infections has considerably widened the spectrum of their role in health and disease. Here, we propose a narrative review that first describes these new platelet attributes. We then examine their relevance to microcirculatory alterations in multi-organ dysfunction, a major sepsis complication. Rapid progresses that are made on the knowledge of novel platelet functions should improve the understanding of thrombocytopenia, a common condition and a predictor of adverse outcome in sepsis, and may provide potential avenues for management and therapy.

Coagulation and sepsis

Severe sepsis is almost invariably associated with systemic activation of coagulation. There is ample evidence that demonstrates a wide-ranging cross-talk between hemostasis and inflammation, which is probably implicated in the pathogenesis of organ dysfunction in patients with sepsis. Inflammation not only leads to initiation and propagation of coagulation activity, but coagulation also markedly influences inflammation. Molecular mechanisms that play a role in inflammation-induced effects on coagulation have been recognized in much detail. Pro-inflammatory cells and cyto- and chemokines can activate the coagulation system and downregulate crucial physiological anticoagulant mechanisms. Initiation of coagulation activation and consequent thrombin generation is caused by expression of tissue factor on activated monocytes and endothelial cells and is ineffectually offset by tissue factor pathway inhibitor. At the same time, endothelial-associated anticoagulant pathways, in particular the protein C system, is impaired by pro-inflammatory cytokines. Also, fibrin removal is severely obstructed by inactivation of the endogenous fibrinolytic system, mainly as a result of upregulation of its principal inhibitor, plasminogen activator inhibitor type 1 (PAI-1). Increased fibrin generation and impaired break down lead to deposition of (micro)vascular clots, which may contribute to tissue ischemia and ensuing organ dysfunction. The foundation of the management of coagulation in sepsis is the explicit and thorough treatment of the underlying disorder by antibiotic treatment and source control measures. Adjunctive strategies focused at the impairment of coagulation, including anticoagulants and restoration of physiological anticoagulant mechanisms, may supposedly be indicated and have been found advantageous in experimental and initial clinical trials.

Nonthrombotic proliferative vasculopathy associated with antiphospholipid antibodies: A case report and literature review

A 20-year-old man presented with recurrent hemoptysis for seven months. A small subpleural nodule in his right lower lobe was found and excised surgically. Based on the presence of antiphospholipid antibodies (aPL) and vascular wall hypertrophy without vasculitis or an intraluminal thrombus, nonthrombotic proliferative vasculopathy (NTPV) affecting pulmonary arteries was diagnosed. Recently, aPL have been postulated to directly induce the proliferation of vascular cells in the intima and media, leading to NTPV. We review 5 cases of NTPV-associated aPL with critical ischemia in the lower extremities and gastrointestinal infarction. NTPV-associated aPL might be distinct from classic antiphospholipid syndrome and should be considered in aPL-positive patients who present with vascular occlusions of medium-sized vessels in the absence of atherosclerotic risk factors and systemic or local inflammation.

Catastrophic Antiphospholipid Syndrome

Catastrophic antiphospholipid syndrome is a rapidly progressive life-threatening disease that causes multiple organ thromboses and dysfunction in the presence of antiphospholipid antibodies. A high index of clinical suspicion and careful investigation are required to make an early diagnosis so that treatment with anticoagulation and corticosteroids can be initiated; plasma exchange and/or intravenous immunoglobulins can be added if the life-threatening condition persists. Despite aggressive treatment and intensive care unit management, patients with catastrophic antiphospholipid syndrome have a 48% mortality rate, primarily attributable to cardiopulmonary failure. This article reviews the current information on the etiopathogenesis, clinical manifestations, diagnosis, management, and prognosis of catastrophic antiphospholipid syndrome.

A Prospective Study of the Clinical Profile, Outcome and Evaluation of D-dimer in Cerebral Venous Thrombosis

INTRODUCTION

Cerebral Venous Thrombosis (CVT) is a well known disease with diverse clinical presentation and causes. With advances in neuroimaging and changing lifestyles, the clinical profile and causes of CVT are changing. D-dimer has been studied in early diagnosis of CVT with variable results. This prospective study was carried out to assess the clinical profile of CVT and role of D-dimer in diagnosis of CVT.

AIM

To study various aspects of CVT and role of D-dimer.

MATERIALS AND METHODS

The study period was September 2012 to July 2014 and included 80 imaging proven patients of CVT. We also included 39 controls for assessing D-dimer. Data was collected according to a preformed format. D-dimer was assessed by a rapid semi-quantitative latex agglutination assay. Discharged patients were followed up to six months.

RESULTS

Of the total 44 were women and 36 were men (F: M=1.2:1). The mean age of the patients was 29.5±9.68 years. Most common clinical features were headache 77 (96.25%), papilloedema (67.5%) and seizures 51 (63.75%). Pregnancy was the most common cause of CVT. Superior sagittal and transverse sinuses were the most common sinuses to be affected. The sensitivity and specificity of D-dimer for diagnosing CVT was 84.62% and 80% respectively. The risk factors for poor prognosis were altered sensorium, presence of sepsis, increased sinus involvement and deep sinus thrombosis.

CONCLUSION

CVT affects both sexes equally. Puerperium still contributes to majority of the cases. Iron deficiency anaemia needs to be evaluated as a contributing factor for incidence of CVT. D-dimer is not useful in puerperal female with CVT. Positive D-dimer will strengthen the suspicion of CVT in patients with acute headache followed by a neurological deficit.

The pathophysiology of thrombocytopenia in chronic liver disease

Thrombocytopenia is the most common hematological abnormality encountered in patients with chronic liver disease (CLD). In addition to being an indicator of advanced disease and poor prognosis, it frequently prevents crucial interventions. Historically, thrombocytopenia has been attributed to hypersplenism, which is the increased pooling of platelets in a spleen enlarged by congestive splenomegaly secondary to portal hypertension. Over the past decade, however, there have been significant advances in the understanding of thrombopoiesis, which, in turn, has led to an improved understanding of thrombocytopenia in cirrhosis. Multiple factors contribute to the development of thrombocytopenia and these can broadly be divided into those that cause decreased production, splenic sequestration, and increased destruction. Depressed thrombopoietin levels in CLD, together with direct bone marrow suppression, result in a reduced rate of platelet production. Thrombopoietin regulates both platelet production and maturation and is impaired in CLD. Bone marrow suppression can be caused by viruses, alcohol, iron overload, and medications. Splenic sequestration results from hypersplenism. The increased rate of platelet destruction in cirrhosis also occurs through a number of pathways: increased shear stress, increased fibrinolysis, bacterial translocation, and infection result in an increased rate of platelet aggregation, while autoimmune disease and raised titers of antiplatelet immunoglobulin result in the immunologic destruction of platelets. An in-depth understanding of the complex pathophysiology of the thrombocytopenia of CLD is crucial when considering treatment strategies. This review outlines the recent advances in our understanding of thrombocytopenia in cirrhosis and CLD.

Thrombocytopenia: A Risk Factor of Mortality for Patients with Sepsis in the Intensive Care Unit

OBJECTIVES

The objective of this study was to evaluate the intensive care unit (ICU) and long-term mortality in sepsis patients with/without thrombocytopenia on the fifth day of ICU admission.

MATERIALS AND METHODS

The retrospective observational cohort study was performed in a teaching hospital, and patients with sepsis who stayed more than 4 days in the ICU between January 2012 and December 2012 were included. Patients were divided into two groups according to thier platelet count at fifth day of ICU stay: Group 1, < 150.000/μL; Group 2, >150.000/μL. Patients having thrombocytopenia on admission were excluded. The patients' characteristics, comorbid diseases, body mass index, arterial blood gas analysis and blood biochemistry results, SIRS criteria, Acute Physiological and Chronic Health Evaluation Score II (APACHE II), implication of invasive and non-invasive mechanical ventilation, use of sedation, nutrition information, and culture results of microbiological samples were recorded. The groups were compared according to the recorded data. Logistic regression analysis was performed for ICU mortality; the Kaplan-Meier test was used to evaluate 12-month survival after ICU discharge.

RESULTS

During the period, 1003 patients were admitted to the ICU; 307 sepsis patients were included in the study. Group 1 (n= 67) and Group 2 (n=240) had similar patient characteristics and sepsis findings. The groups had similar ICU and hospital stays; mortality was higher in Group 1 than in Group 2 (40.3% vs. 17.5%, respectively, p< 0.001). Fifth day thrombocytopenia, septic shock, male gender, and low albumin levels were found to be risk factors of ICU mortality; the respective odds ratios, 95% confidence intervals, and p values for these factors were 3.03, [1.15-7.45], p= 0.025; 4.97, [1.79-13.86], p= 0.002; 3.61, [1.27-10.23], p= 0.001; and 0.19, [0.07-0.52], p= 0.001. Follow-up after a year indicated that 124 out of 238 (52.1%) patients died, and 50% of the deaths occurred in the first 2 months. Kaplan-Meier analysis revealed no statistically significant effects of thrombocytopenia at ICU day 5 on 12-month mortality after ICU discharge.

CONCLUSION

Higher rates of septic shock and mortality were seen in sepsis patients with thrombocytopenia in the ICU. The measurement of thrombocytopenia in the ICU, which is easy and low-cost, may help to predict mortality. Thus, precautions can be taken early in patient treatment and follow-up. As we know, early intervention is crucial in the approach to sepsis.

Mean platelet volume as a novel predictor of systemic inflammatory response in cirrhotic patients with culture-negative neutrocytic ascites

AIM: To identify a mean platelet volume (MPV) cutoff value which should be able to predict the presence of bacterial infection.

METHODS: An observational, analytic, retrospective study. We evaluated medical records of cirrhotic patients who were hospitalized from January 2012 to January 2014 at the Gastroenterology Department of “Hospital General de México Dr. Eduardo Liceaga”, we included 51 cirrhotic patients with ascites fluid infection (AFI), and 50 non-infected cirrhotic patients as control group. Receiver operator characteristic curves were used to identify the best cutoff value of several parameters from hematic cytometry, including MPV, to predict the presence of ascites fluid infection.

RESULTS: Of the 51 cases with AFI, 48 patients (94.1%) had culture-negative neutrocytic ascites (CNNA), 2 (3.9%) had bacterial ascites, and one (2%) had spontaneous bacterial peritonitis. Infected patients had greater count of leucocytes and polymorphonuclear cells, greater levels of MPV and cardiac frequency (P < 0.0001), and lower mean arterial pressure compared with non-infected patients (P = 0.009). Leucocytes, polymorphonuclear count, MPV and cardiac frequency resulted to be good or very good predictive variables of presence of AFI in cirrhotic patients (area under the receiving operating characteristic > 0.80). A cutoff MPV value of 8.3 fl was the best to discriminate between cirrhotic patients with AFI and those without infection.

CONCLUSION: Our results support that MPV can be an useful predictor of systemic inflammatory response syndrome in cirrhotic patients with AFI, particularly CNNA.

Hemostatic abnormalities in critically ill patients

Hemostatic abnormalities frequently occur in critically ill patients and may vary from prolonged global clotting tests or isolated thrombocytopenia, to composite defects, such as consumption coagulopathies. There are many reasons for a disturbed coagulation in intensive care patients, and each of these underlying syndromes may require specific therapeutic intervention. Hence, an adequate differential diagnosis and initiation of proper (supportive) therapeutic strategies are critical to decrease morbidity and mortality in critically ill patients with hemostatic abnormalities.

Coagulation and the vessel wall in pulmonary embolism

Venous thromboembolism comprises deep-vein thrombosis, thrombus in transit, acute pulmonary embolism, and chronic thromboembolic pulmonary hypertension (CTEPH). Pulmonary thromboemboli commonly resolve, with restoration of normal pulmonary hemodynamics. When they fail to resorb, permanent occlusion of the deep veins and/or CTEPH are the consequences. Apart from endogenous fibrinolysis, venous thrombi resolve by a process of mechanical fragmentation, through organization of the thromboembolus by invasion of endothelial cells, leukocytes, and fibroblasts leading to recanalization. Recent data utilizing various models have contributed to a better understanding of venous thrombosis and the resolution process that is directed at maintaining vascular patency. This review summarizes the plasmatic and cellular components of venous thrombus formation and resolution.

An increase in mean platelet volume after admission is associated with higher mortality in critically ill patients

Background

Platelet activation and consumption are common in critically ill patients and are associated with poorer prognosis. Mean platelet volume is a simple surrogate for platelet activation, with higher MPV being associated with worse clinical condition on a large array of clinical diagnoses. We therefore aimed to investigate associations between changes in platelet count and mean platelet volume (MPV) with prognosis and inflammatory cytokine values in critically ill patients.

Methods

This study prospectively included 84 critically ill patients. Patients were stratified into four groups according to proportional changes in MPV (ΔMPV_24h) and platelet count (ΔPlat_24h) in the first 24 hours after admission. Mortality between groups was compared using the χ² test. Logistic regression was performed using hospital mortality as outcome and Simplified Acute Physiology Score (SAPS 3), ΔPlat_24h and ΔMPV_24h as covariates. Concentrations of the following inflammatory mediators were measured using Miliplex® technology: IL1β, IL6, IL8, IL10, epidermal growth factor, vascular endothelial growth factor, TNFα and IFNα. Cytokine concentrations were compared between groups using the Kruskal-Wallis test with Bonferroni correction.

Results

Patients in whom MPV increased and platelet count decreased had higher mortality rates (46%). According to logistic regression, ΔMPV_24h was independently associated with increased mortality (OR 1.28 per 1% increase; 95% CI 1.08 to 1.48). No strong associations between inflammatory mediators and changes in MPV and platelet count were found.

Conclusion

An increase in MPV after admission to an ICU is independently associated with higher hospital mortality.

Overview of platelet physiology: its hemostatic and nonhemostatic role in disease pathogenesis

Platelets are small anucleate cell fragments that circulate in blood playing crucial role in managing vascular integrity and regulating hemostasis. Platelets are also involved in the fundamental biological process of chronic inflammation associated with disease pathology. Platelet indices like mean platelets volume (MPV), platelets distributed width (PDW), and platelet crit (PCT) are useful as cheap noninvasive biomarkers for assessing the diseased states. Dynamic platelets bear distinct morphology, where α and dense granule are actively involved in secretion of molecules like GPIIb , IIIa, fibrinogen, vWf, catecholamines, serotonin, calcium, ATP, ADP, and so forth, which are involved in aggregation. Differential expressions of surface receptors like CD36, CD41, CD61 and so forth have also been quantitated in several diseases. Platelet clinical research faces challenges due to the vulnerable nature of platelet structure functions and lack of accurate assay techniques. But recent advancement in flow cytometry inputs huge progress in the field of platelets study. Platelets activation and dysfunction have been implicated in diabetes, renal diseases, tumorigenesis, Alzheimer's, and CVD. In conclusion, this paper elucidates that platelets are not that innocent as they keep showing and thus numerous novel platelet biomarkers are upcoming very soon in the field of clinical research which can be important for predicting and diagnosing disease state.

Immature platelet fraction levels in a variety of bone marrow pathologies in South African HIV-positive patients with thrombocytopenia

OBJECTIVES

Thrombocytopenia is common in HIV-infected individuals and often requires a diagnostic bone marrow examination. Interpretation may, however, be limited due to the multifactorial nature of HIV-associated thrombocytopenia and the difficulty in assessing megakaryocyte function morphologically. The immature platelet fraction (IPF) is a parameter which reportedly reflects megakaryocyte activity, with an IPF >7.7% suggesting increased platelet production. The aim of this study was to correlate the IPF with the bone marrow findings as well as other clinical variables of interest in South African patients with HIV-associated thrombocytopenia.

METHODS

Seventy-eight HIV-positive patients with thrombocytopenia were enrolled from the Charlotte Maxeke Johannesburg Academic Hospital. The IPF levels were measured using a Sysmex XE-5000 haematology analyzer and were correlated with bone marrow and other findings.

RESULTS

The median IPF was 7.6%, ranging from 1.3 to 44%. It was raised in 78% of patients with immune thrombocytopenia (ITP) (median = 16.3%) and low in 79% of patients with hypocellular marrow (median = 6.5%). Surprisingly, it was highly variable among patients with malignant marrow infiltration and mycobacterial infection of the bone marrow (BMTB) (median = 8.4 and 7.1%, respectively). Multivariate linear regression analysis confirmed a significant independent inverse relationship between the IPF and hypocellular marrow (P < 0.0001), a marginally significant positive association with ITP (P = 0.059), and the absence of any relationship with malignant infiltration or BMTB. The IPF had a significant inverse association with the platelet count (P = 0.0006), but was unrelated to the CD4 count and exposure to anti-retroviral therapy. Unexpectedly, it showed a significant positive association with the HIV viral load (P = 0.005). We speculate this to reflect increased megakaryocyte activity in compensation for accelerated platelet clearance due to HIV-driven platelet activation.

CONCLUSION

This study investigates the role of the IPF in HIV-associated thrombocytopenia, and emphasizes the limitations of morphological analysis in determining megakaryocyte function.

Management of heparin-induced thrombocytopenia (HIT) in patients with systemic vasculitis and pulmonary haemorrhage

Heparin-induced thrombocytopenia (HIT) is a relatively uncommon but potentially fatal complication of the use of heparin in haemodialysis. It is associated with a risk of venous and arterial thrombosis due to the formation of a heparin-platelet factor 4 antibody. Early recognition and immediate treatment of HIT are crucial to reduce the morbidity and mortality rate. Here, we report two patients with acute kidney injury due to anti-glomerular membrane (GBM) glomerulonephritis and granulomatosis with polyangiitis respectively who developed haemoptysis and pulmonary haemorrhage complicated by HIT. We discuss the diagnostic and management challenges of such patients.

Effect of severe sepsis on platelet count and their indices

BACKGROUND

Sepsis is a major disease affecting almost all organs and systems.

OBJECTIVES

To examine platelet count and indices (mean platelet volume (MPV) and platelet distribution width (PDW)) in severe sepsis.

METHODS

Patients with criteria for sepsis at a first examination by an Infectious Diseases specialist were selected. Consecutive patients who were admitted to the out-patient clinic and who were not diagnosed with any infectious disease were selected as the control group.

RESULTS

A total of 145 patients with sepsis and 143 patients as a control group were included in the study. MPV and PDW were significantly differentbetween sepsis patients and control group (P<0.05). Platelet count in sepsis patients was lower than control group but the difference was not significant. PDW was the unique significantly different parameter between survivors and non-survivors (p=0.001).

CONCLUSION

Platelet indices are important laboratory findings in the diagnosis of sepsis and severe sepsis. Severe sepsis patients who have greater than 18 % PDW levels have a higher risk of death. Therefore, PDW, which is part of an inexpensive, easily accessible and routinely performed test for almost all patients admitted to health facilities may be used for predicting mortality.

Meningococcemia and heparin-induced thrombocytopenia: a dangerous combination

We present a dramatic case of a patient presenting with disseminated intravascular coagulation related to meningococcal sepsis who developed heparin-induced thrombocytopenia following heparin administration during continuous renal replacement therapy. Association of these two prothrombotic conditions led to severe limbs ischemia and finally to bilateral legs amputation. We stress the importance of suspect heparin-induced thrombocytopenia in intensive care unit patients, especially when an improvement of other coagulation parameters is observed, and heparin therapy was started.

Anticoagulant use in real time

Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Each year, VTE affects about 300,000 to 600,000 people in the United States, and death is the first manifestation in one-fourth of this population.(1){Beckman, 2010 #79} Moreover, approximately 10% of the US population has genetic factors that increase their risk for developing thrombosis.(1) In addition to inherited disorders, factors that contribute to VTE include prolonged immobilization, trauma, surgery, cancer, and critically ill patients.(2) Routine assessment and prophylaxis are recommended in these groups to avoid DVT-related complications.(2) Anticoagulants are the mainstay of drugs used in DVT/PE prevention and treatment. Despite the availability of evidence-based guidelines for anticoagulant therapy, there is suboptimal implementation of DVT prophylaxis in hospitalized patients.(3) All anticoagulants are "high-alert" drugs, and judicious use is mandatory to prevent bleeding complications.(4) This review discusses treatment guidelines, monitoring, side effects, and reversal agents available for some anticoagulant drugs approved for VTE. Dissemination of the knowledge via pharmacy education programs significantly improves the adherence to VTE prophylaxis.(5) Understanding the clinical aspects of anticoagulant dispensing as presented in this review is hoped to facilitate implementation of the theoretical knowledge as well as evidence-based guidelines in order to maximize patient benefit.

Etiology and significance of thrombocytopenia in critically ill patients

Thrombocytopenia is common in critically ill patients and increases morbidity and mortality. A diagnosis of heparin-induced thrombocytopenia (HIT) is frequently considered in any ICU patient who develops thrombocytopenia in the context of ongoing heparin exposure. As the usual tests to diagnose HIT are often neither specific nor sensitive enough to be confirmatory, the intensivist must largely rely on clinical judgment in treatment decisions. Patients in the ICU may also develop thrombocytopenia resulting from non-HIT immune mechanisms, nonimmune platelet consumption, and from decreased platelet production due to preexisting disorders or as a result of their critical illness and/or drug therapy.

Thrombotic obstruction of the central venous catheter in patients undergoing hematopoietic stem cell transplantation

This is an integrative literature review with the aim of summarizing the prevention measures and treatment of thrombotic obstruction of long-term semi-implanted central venous catheters, in patients undergoing hematopoietic stem cell transplantation. The sample consisted of seven studies, being two randomized controlled clinical trials, three cohort studies and two case series. Regarding the prevention measures, one single study demonstrated effectiveness, which was a cohort study on the oral use of warfarin. In relation to the treatment measures, three studies evidenced effectiveness, one highlighted the efficacy of streptokinase or urokinase, one demonstrated the benefit of using low-molecular-weight heparin and the other treated the obstruction with heparin or urokinase. Catheter patency research shows a restricted evolution that does not follow the evolution of transplantations, mainly regarding nursing care.

Heparin induced thrombocytopenia: case presentation and review

Heparin Induced Thrombocytopenia (HIT) is an adverse effect of heparin therapy with possibly devastating consequences. We present a case of HIT Type II. An in-depth review of HIT is presented, examining the important clinical symptoms and diagnostic indicators. The treatment of HIT is then discussed, with an emphasis on current therapies. An extensive literature review has been performed to present a comprehensive review of the causes, pathophysiology and treatment of HIT.

Coagulation biomarkers in critically ill patients

This article discusses coagulation biomarkers in critically ill patients where coagulation abnormalities occur frequently and may have a major impact on the outcome. An adequate explanation for the cause is important, since many underlying disorders may require specific treatment and supportive therapy directed at the underlying condition. Deficiencies in platelets and coagulation factors in bleeding patients or patients at risk for bleeding can be achieved by transfusion of platelet concentrate or plasma products, respectively. Prohemostatic treatment may be beneficial in case of severe bleeding, whereas restoring physiological anticoagulant pathways may be helpful in patients with sepsis and disseminated intravascular coagulation.

The septic milieu triggers expression of spliced tissue factor mRNA in human platelets

BACKGROUND

Activated platelets have previously-unrecognized mechanisms of post-transcriptional gene expression that may influence hemostasis and inflammation. A novel pathway involves splicing of pre-mRNAs in resting platelets to mature, translatable mRNAs in response to cellular activation.

OBJECTIVES

We asked if bacterial products and host agonists present in the septic milieu induce tissue factor pre-mRNA splicing in platelets from healthy subjects. In parallel, we asked if spliced tissue factor (TF) mRNA is present in platelets from septic patients in a proof-of-principle analysis.

PATIENTS/METHODS

TF pre-mRNA and mRNA expression patterns were characterized in platelets from septic patients and in platelets isolated from healthy subjects activated with bacteria, toxins and inflammatory agonists. Procoagulant activity was also measured.

RESULTS AND CONCLUSIONS

Live bacteria, staphylococcal α-toxin and lipopolysaccharide (LPS) induced TF pre-mRNA splicing in platelets isolated from healthy subjects. Toxin-stimulated platelets accelerated plasma clotting, a response that was blocked by a previously-characterized splicing inhibitor and by an anti-tissue factor antibody. Platelets from septic patients expressed spliced TF mRNA, whereas it was absent from unselected and age-matched control subjects. Tissue factor-dependent procoagulant activity was elevated in platelets from a subset of septic patients. Thus, bacterial and host factors induce splicing of TF pre-mRNA, expression of TF mRNA and tissue factor-dependent clotting activity in human platelets. TF mRNA is present in platelets from some septic patients, indicating that it may be a marker of altered platelet phenotype and function in sepsis and that splicing pathways are induced in this syndrome.

Association between serum soluble CD40 ligand levels and mortality in patients with severe sepsis

INTRODUCTION

CD40 Ligand (CD40L) and its soluble counterpart (sCD40L) are proteins that exhibit prothrombotic and proinflammatory properties on binding to their cell surface receptor CD40. The results of small clinical studies suggest that sCD40L levels could play a role in sepsis; however, there are no data on the association between sCD40L levels and mortality of septic patients. Thus, the aim of this study was to determine whether circulating sCD40L levels could be a marker of adverse outcome in a large cohort of patients with severe sepsis.

METHODS

This was a multicenter, observational and prospective study carried out in six Spanish intensive care units. Serum levels of sCD40L, tumour necrosis factor-alpha and interleukin-10, and plasma levels of tissue factor were measured in 186 patients with severe sepsis at the time of diagnosis. Serum sCD40L was also measured in 50 age- and sex-matched controls. Survival at 30 days was used as the endpoint.

RESULTS

Circulating sCD40L levels were significantly higher in septic patients than in controls (P = 0.01), and in non-survivors (n = 62) compared to survivors (n = 124) (P = 0.04). However, the levels of CD40L were not different regarding sepsis severity. Logistic regression analysis showed that sCD40L levels >3.5 ng/mL were associated with higher mortality at 30 days (odds ratio = 2.89; 95% confidence interval = 1.37 to 6.07; P = 0.005). The area under the curve of sCD40L levels >3.5 ng/mL as predictor of mortality at 30 days was 0.58 (95% CI = 0.51 to 0.65; P = 0.03).

CONCLUSIONS

In conclusion, circulating sCD40L levels are increased in septic patients and are independently associated with mortality in these patients; thus, its modulation could represent an attractive therapeutic target.

Antiphospholipid syndrome; its implication in cardiovascular diseases: a review

Antiphospholipid syndrome (APLS) is a rare syndrome mainly characterized by several hyper-coagulable complications and therefore, implicated in the operated cardiac surgery patient. APLS comprises clinical features such as arterial or venous thromboses, valve disease, coronary artery disease, intracardiac thrombus formation, pulmonary hypertension and dilated cardiomyopathy. The most commonly affected valve is the mitral, followed by the aortic and tricuspid valve. For APLS diagnosis essential is the detection of so-called antiphospholipid antibodies (aPL) as anticardiolipin antibodies (aCL) or lupus anticoagulant (LA). Minor alterations in the anticoagulation, infection, and surgical stress may trigger widespread thrombosis. The incidence of thrombosis is highest during the following perioperative periods: preoperatively during the withdrawal of warfarin, postoperatively during the period of hypercoagulability despite warfarin or heparin therapy, or postoperatively before adequate anticoagulation achievement. Cardiac valvular pathology includes irregular thickening of the valve leaflets due to deposition of immune complexes that may lead to vegetations and valve dysfunction; a significant risk factor for stroke. Patients with APLS are at increased risk for thrombosis and adequate anticoagulation is of vital importance during cardiopulmonary bypass (CPB). A successful outcome requires multidisciplinary management in order to prevent thrombotic or bleeding complications and to manage perioperative anticoagulation. More work and reporting on anticoagulation management and adjuvant therapy in patients with APLS during extracorporeal circulation are necessary.

Nosocomial sepsis-induced late onset thrombocytopenia in a neonatal tertiary care unit: a prospective study

BACKGROUND AND OBJECTIVES

Late onset sepsis (LOS)( onset of sepsis >72 hours of age or nosocomial sepsis) is an important cause of morbidity and mortality in the neonatal intensive care unit (NICU). Thrombocytopenia is an important complication of sepsis. We investigated the incidence of thrombocytopenia in LOS patients and studied the influence of various parameters on platelet response.

PATIENTS AND METHODS

Infants born in the level 3 neonatal intensive care unit between January 2002 and December 2006 with documented LOS were included in this prospective study. Multiple hemograms with platelet counts, bacterial blood culture and fungal blood culture were obtained in all patients. Demographic and clinical data were compared between patients without thrombocytopenia and with mild, moderate and severe thrombocytopenia. Duration of thrombocytopenia in relation to type of organism and mortality with respect to degree of thrombocytopenia were also studied.

RESULTS

Of 200 patients with culture-proven nosocomial sepsis, 119 (59.5%) patients developed thrombocytopenia (platelet count <150 X 109/L). In our series Klebsiella pneumoniae was the most frequently isolated organism (125/200, 62.5%) and the incidence of thrombocytopenia was 60.0% (75/125). However, the incidence of thrombo- cytopenia was highest among patients who had concurrent bacterial and fungal sepsis (28/31, 90.3%). Coagulase- negative staphylococcal (CoNS) sepsis was present in 21 (10.5%) patients and the incidence of thrombocytopenia was 33.3%. Isolated fungal sepsis was present only in 6 (3%) patients and the incidence of thrombocytopenia was 66.0%. The incidence of thrombocytopenia was highest among preterm babies and low-birth weight (LBW) babies. Twenty-seven percent (54/200) of babies presented with mild thrombocytopenia, 20% (40/200) presented with moderate thrombocytopenia, and 12.5%(25/200) developed severe thrombocytopenia. Severity of thrombocytopenia was also directly related to the presence of necrotizing enterocolitis (NEC) and disseminated intravascular coagulation (DIC). The mortality rate was significantly associated with the degree of thrombocytopenia.

CONCLUSION

LOS sepsis is an important risk factor for thrombocytopenia in the NICU. Fungal and gram- negative sepsis are frequently associated with a decreased platelet count. Sepsis-induced thrombocytopenia is more common among LBW babies and preterm babies. The mortality rate is significantly related to degree of thrombocytopenia.

Abnormal coagulation tests obtained in the emergency department are associated with mortality in patients with suspected infection

BACKGROUND

Early recognition of acute organ dysfunction in emergency department (ED) patients with suspected infection may help select patients at increased risk of mortality. The hematologic system is often overlooked in the evaluation and management of patients with infection because it is poorly circumscribed and serves a multitude of functions.

STUDY OBJECTIVES

We examine the hypothesis that abnormalities in commonly and easily obtained markers of coagulation function (international normalized ratio [INR], partial thromboplastin time [PTT], and platelet count [PLT]) are associated with mortality in ED patients admitted to the hospital with suspected infection.

METHODS

DESIGN

Secondary analysis of a prospective observational cohort study.

SETTING

Urban tertiary care university hospital with 50,000 annual ED visits.

PATIENTS

Included patients: adults (age 18 ≥ years) evaluated in the ED for a suspected infection, had an INR, PTT, and PLT obtained during the ED stay, admitted to the hospital. Excluded patients: on oral anticoagulant therapy, received heparin, or pre-existing severe liver disease.

RESULTS

There were 1688 patients included. The in-hospital mortality rate was 5.9%. After adjusting for elderly status, comorbid illness burden, and severity of illness, elevated INR was associated with a 2.9 (95% confidence interval [CI] 1.6-5.2) increased odds of death, and a low platelet count (< 150,000/uL) was associated with 2.0 (95% CI 1.2-3.3) increased odds of death. The C-statistic for the model was 0.80.

CONCLUSION

We found an independent association between abnormalities in the coagulation system and mortality in ED patients with suspected infection. These findings underscore the close interaction between inflammation and coagulation and provide evidence that these simple laboratory tests should be routinely considered during the early evaluation of the infected patient.