Thrombotic thrombocytopenic purpura associated with ticlopidine. A review of 60 cases

Systemic Barriers and Potential Concerns from Reporting Serious Adverse Drug Reactions

About 1-10% of all serious adverse drug reactions (sADRs) are reported to the Food and Drug Administration (FDA) ( Moore T, Bennett C. Underreporting of Hemorrhagic and Thrombotic Complications of Pharmaceuticals to the U.S. Food and Drug Administration: Empirical Findings for Warfarin, Clopidogrel, Ticlopidine, and Thalidomide from the Southern Network on Adverse Reactions (SONAR). Semin Thromb Hemost. 2012;38(08):905-907. https://doi.org/10.1055/s-0032-1328890 ). Prevailing opinion suggests that low reporting rates reflect time constraints.

Plasmapheresis in Sepsis-induced Thrombotic Microangiopathy: A Case Series

Introduction

Cytokines and granulocyte elastase produced in sepsis cleave a disintegrin and metalloprotease with thrombospondin type I motif 13 (ADAMTS13) and deplete its levels. By this mechanism, sepsis results in microangiopathic hemolytic anemia (MAHA) with thrombocytopenia. Hence, the hypothesis is that plasmapheresis may help in sepsis-induced thrombotic microangiopathy (sTMA), by removing the factors responsible for low levels of ADAMTS13. In tropical countries like India, the contribution of sepsis to intensive care unit (ICU) mortality is high; and hence, it is essential to look out for newer modalities of sepsis treatment. There is abundant literature on the use of plasmapheresis in sepsis but data on its use in sTMA are limited, thus necessitating further research in this field.

Case description

This case series studies the outcomes of five patients admitted with sTMA in the ICU and attempts to evaluate the effectiveness of plasmapheresis in improving their outcomes. All patients diagnosed with sTMA and treated with plasmapheresis, between January 2016 and August 2018 at our tertiary care center, were selected for the study. The diagnosis of sepsis was based on sepsis-3 definition.

Results

Four different gram-negative organisms were found to have caused MAHA, with the commonest source being either urinary tract infection (UTI) or lower respiratory tract infection. Three of five patients required hemodialysis and two had disseminated intravascular coagulation (DIC). All five had good outcome and recovered well from the acute episode post plasmapheresis.

Discussion

In two of five patients, the initial smear was negative and hence the need for repeated examination of the peripheral blood smear should be kept in mind in cases of sTMAs. The median of the number of plasmapheresis sessions required in sTMA is six, which is lesser than that required for primary thrombotic thrombocytopenic purpura (TTP). Hence, the duration of central line placement and the risk of catheter-related complications are low. Based on the observations made in this case study, further exploratory studies are required to evaluate the efficacy of plasmapheresis in sTMA secondary to tropical infections.

How to cite this article

Upadhya SRS, Mahabala C, Kamat JG, Jeganathan J, Kumar S, Prabhu MV. Plasmapheresis in Sepsis-induced Thrombotic Microangiopathy: A Case Series. Indian J Crit Care Med 2020;24(3):195–199.

Haemolytic uremic syndrome: diagnosis and management

The thrombotic microangiopathies (TMAs) are a group of diseases characterised by microangiopathic haemolysis, thrombocytopenia, and thrombus formation leading to tissue injury. Traditionally, TMAs have been classified as either thrombotic thrombocytopenic purpura (TTP) or haemolytic uremic syndrome (HUS) based on the clinical presentation, with neurological involvement predominating in the former and acute kidney injury in the latter. However, as our understanding of the pathogenesis of these conditions has increased, it has become clear that this is an over-simplification; there is significant overlap in the clinical presentation of TTP and HUS, there are different forms of HUS, and TMAs can occur in other, diverse clinical scenarios. This review will discuss recent developments in the diagnosis of HUS, focusing on the different forms of HUS and how to diagnose and manage these potentially life-threatening diseases.

[Adverse drug reactions reported to the Brazilian pharmacovigilance system from 2008 to 2013: descriptive study]

The study aimed to analyze suspected adverse drug reactions reported to Brazil's pharmacovigilance system (Notivisa-medicamento) from 2008 to 2013. This was a descriptive study whose analytical units in the database were reports and drug-adverse reactions pairs. A total of 26,554 reports were identified, for a reporting rate of 22.8/million inhabitants/year. Reports in female patients prevailed (60.5%), as did white color/race (58.1%). Age ranged from 0 to 112 years (median = 46 years). Nearly one-third (32.5%) of suspected adverse drug reactions occurred in vulnerable populations (elderly and children). A total of 54,288 drug- adverse reactions pairs were analyzed, with a prevalence of severe adverse drug reactions (59.2%), featuring those that resulted in clinically important effects (83.1%). The most frequent drugs in severe adverse drug reactions belonged to groups L, antineoplastic and immunomodulating agents (32.1%), and J, general anti-infectious agents for systemic use (27%), while the most affected system-organ-class was conditions of the skin and related disorders (23.7%). Notivisa-medicamento is an important resource for producing warning signs and hypotheses on the safety of drugs marketed in Brazil. However, the reporting rate per million inhabitants/year was far lower than that described in middle and high-income countries.

A Rare Case of Thrombotic Thrombocytopenic Purpura Caused by Pancreatitis and Clopidogrel

Patient: Male, 71

Final Diagnosis: Thrombotic thrombocytopenic purpura

Symptoms: Abdominal and/or epigastric pain

Medication: —

Clinical Procedure: —

Specialty: General and Internal Medicine

ADAMTS13: origins, applications, and prospects

ADAMTS13 is an enzyme that acts by cleaving prothrombotic von Willebrand factor (VWF) multimers from the vasculature in a highly regulated manner. In pathologic states such as thrombotic thrombocytopenic purpura (TTP) and other thrombotic microangiopathies (TMAs), VWF can bind to the endothelium and form large multimers. As the anchored VWF chains grow, they provide a greater surface area to bind circulating platelets (PLTs), generating unique thrombi that characterize TTP. This results in microvasculature thrombosis, obstruction of blood flow, and ultimately end-organ damage. Initial presentations of TTP usually occur in an acute manner, typically developing due to an autoimmune response toward, or less commonly a congenital deficiency of, ADAMTS13. Triggers for TMAs that can be associated with ADAMTS13 deficiency, including TTP, have been linked to events that place a burden on hemostatic regulation, such as major trauma and pregnancy. The treatment plan for cases of suspected TTP consists of emergent therapeutic plasma exchange that is continued on a daily basis until normalization of PLT counts. However, a subset of these patients does not respond favorably to standard therapies. These patients necessitate a better understanding of their diseases for the advancement of future therapeutic options. Given ADAMTS13's key role in the cleavage of VWF and the prevention of PLT-rich thrombi within the microvasculature, future treatments may include anti-VWF therapeutics, recombinant ADAMTS13 infusions, and ADAMTS13 expression via gene therapy.

Diagnostic modalities in peripheral artery disease

Peripheral artery disease (PAD) affects approximately one in five persons older than 70 years of age and it is often present in patients with concomitant vascular disease in different body territories (e.g. coronary artery disease). Diagnosis at an early stage is important in order to achieve improvement in patient's symptoms and prognosis. Remarkable improvements in the field of noninvasive and invasive imaging techniques have led to an advanced level the management of patients with PAD. Throughout this review article, the clinically available diagnostic modalities in PAD are presented. Strong and weaker points are stressed out in a manner that elucidates that no perfect diagnostic method exists. Based on the patient's individual profile, as well as on certain aspects of the disease (e.g. morphology of carotid plaque lesions) the attending physician will ultimately decide which diagnostic path will lead to a prompt and correct diagnosis of PAD with the minimum amount of exams and risk for the patient.

Evaluation and Management of Patients With Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) describes syndromes with multiple etiologies, some of which are rapidly fatal without plasma exchange treatment. Although there have been advances in understanding the pathogenesis of TTP, evaluation and management remain difficult because there are no specific diagnostic criteria, as TTP can be clinically similar to other acute disorders, such as sepsis, disseminated malignancy, malignant hypertension, and preeclampsia, and because urgent treatment is required. An unexpected observation of anemia and thrombocytopenia should trigger consideration of TTP; evidence that the anemia is due to microangiopathic hemolysis, suggested by the presence of red cell fragmentation on the blood smear, supports the diagnosis. When the diagnostic criteria of microangiopathic hemolytic anemia and thrombocytopenia without an apparent alternative etiology are fulfilled, plasma exchange treatment is appropriate. However, plasma exchange has risks for severe complications and death; therefore, this management decision must be balanced against the confidence in the diagnosis. With plasma exchange treatment, approximately 80% of patients survive, in contrast to only 10% in the era prior to the availability of plasma exchange. The continuing mortality from TTP, the risks of plasma exchange treatment, and the potential for recurrent episodes of TTP are clinical challenges that remain to be solved.

Platelets and Cardiovascular Disease

Platelets play an important, but often under-recognized role in cardiovascular disease. For example, the normal response of the platelet can be altered, either by increased pro-aggregatory stimuli or by diminished anti-aggregatory substances to produce conditions of increased platelet activation/aggregation and occur in active cardiovascular disease states both on a chronic (e.g. stable angina pectoris) and acute basis (e.g. acute myocardial infarction). In addition, platelet hyperaggregability is also associated with the risk factors for coronary artery disease (e.g. smoking, hypertension, and hypercholesterolaemia). Finally, the utility of an increasing range of anti-platelet therapies in the management of the above disease states further emphasizes the pivotal role platelets play in the pathogenesis of cardiovascular disease. This paper provides a comprehensive overview of the normal physiologic role of platelets in maintain homeostasis, the pathophysiologic processes that contribute to platelet dysfunction in cardiovascular disease and the associated role and benefits of anti-platelet therapies.

Comparative effects of the anti-platelet drugs, clopidogrel, ticlopidine, and cilostazol on aspirin-induced gastric bleeding and damage in rats

AIMS

The present study compared the effects of frequently used anti-platelet drugs, such as clopidogrel, ticlopidine, and cilostazol, on the gastric bleeding and ulcerogenic responses induced by intraluminal perfusion with 25 mM aspirin acidified with 25 mM HCl (acidified ASA) in rats.

MAIN METHODS

The stomach was perfused with acidified ASA at a rate of 0.4 ml/min for 60 min under urethane anesthesia, and gastric bleeding was measured as the concentration of hemoglobin in the luminal perfusate, which was collected every 15 min. Clopidogrel (10-100mg/kg), ticlopidine (10-300 mg/kg), or cilostazol (3-30 mg/kg) was given p.o. 24h or 90 min before the perfusion of acidified ASA, respectively.

KEY FINDINGS

Perfusion of the stomach with acidified ASA alone led to slight bleeding and lesions in the stomach. The pretreatment with clopidogrel, even though it did not cause bleeding or damage by itself, dose-dependently increased the gastric bleeding and ulcerogenic responses induced by acidified ASA. Ticlopidine also aggravated the severity of damage by increasing gastric bleeding, and the effects of ticlopidine at 300 mg/kg were equivalent to those of clopidogrel at 100mg/kg. In contrast, cilostazol dose-dependently decreased gastric bleeding and damage in response to acidified ASA.

SIGNIFICANCE

These results demonstrated that clopidogrel and ticlopidine, P2Y12 receptor inhibitors, increased gastric bleeding and ulcerogenic responses to acidified ASA, to the same extent, while cilostazol, a phosphodiesterase III inhibitor, suppressed these responses. Therefore, cilostazol may be safely used in dual anti-platelet therapy combined with ASA, without increasing the risk of gastric bleeding.

Cisplatin: process and future

One of the most important anticancer agents is cisplatin (CDDP). Numerous studies with a CDDP-based combination have been reported over the last 30 years. The use of CDDP in the 1980s and 1990s showed responses in advanced stage non-small-cell lung cancer (NSCLC). Over the years it was found that the side effects of this agent (particularly nephrotoxicity) were a common problem. Agents such as carboplatin, taxanes, gemcitabine, irinotecan and pemetrexed proved to be effective in NSCLC with reduced or no nephrotoxicity. The administration of these newer agents improved several side effects, but without improving efficacy. When prophylactic (adjuvant) treatment for NSCLC was introduced, CDDP was the agent selected, which indicated the value of the drug. Recently, a novel formulation of CDDP, liposomal cisplatin, which has shown very low toxicity, no nephrotoxicity and equal effectiveness was produced; its importance is its higher effectiveness than standard CDDP in lung adenocarcinoma.

Results from the first decade of research conducted by the Research on Adverse Drug Events and Reports (RADAR) project

INTRODUCTION

In 1998, a multidisciplinary team of investigators initiated the Research on Adverse Drug events And Reports (RADAR) project, a post-marketing surveillance effort that systematically investigates and disseminates information describing serious and previously unrecognized serious adverse drug and device reactions (sADRs).

OBJECTIVE

Herein, we describe the findings, dissemination efforts, and lessons learned from the first decade of the RADAR project.

METHODS

After identifying serious and unexpected clinical events suitable for further investigation, RADAR collaborators derived case information from physician queries, published and unpublished clinical trials, case reports, US FDA databases and manufacturer sales figures.

STUDY SELECTION

All major RADAR publications from 1998 to the present are included in this analysis.

DATA EXTRACTION

For each RADAR publication, data were abstracted on data source, correlative basic science findings, dissemination and resultant safety information.

RESULTS

RADAR investigators reported 43 serious ADRs. Data sources included case reports (17 sADRs), registries (5 sADRs), referral centers (8 sADRs) and clinical trial reports (13 sADRs). Correlative basic science findings were reported for ten sADRs. Thirty-seven sADRS were described as published case reports (5 sADRs) or published case-series (32 sADRs). Related safety information was disseminated as warnings or boxed warnings in the package insert (17 sADRs) and/or 'Dear Healthcare Professional' letters (14 sADRs).

CONCLUSION

An independent National Institutes of Health-funded post-marketing surveillance programme can supplement existing regulatory and pharmaceutical manufacturer-supported drug safety initiatives.

Commonly used drugs in hematologic disorders

The drugs used to treat hematologic disorders constitute an extraordinary array of agents and include therapy for anemias, bleeding diatheses, thromboembolism and hematologic malignancies. Within many of these categories, hematologic therapies represent molecular understanding of the disease pathophysiology and a treatment targeted precisely at the known aberration. In this chapter we discuss these treatments, with greater emphasis on the most commonly used agents and the latest advances in the specific field. The chapter includes discussion on old (cyclooxygenase inhibitors) and new antiplatelet agents (ADP receptor P2Y12 inhibitors), newly described oral thrombin inhibitors such as dabigatran, treatment targeted at the bcr-abl tyrosine kinase in chronic myeloid leukemia and demethylating agents in myelodysplasia. The discussion is also oriented towards neurologic implications, both therapeutic and toxic, for each therapy or therapeutic group.

Postoperative thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disease characterized by acute episodes of thrombocytopenia and microangiopathic hemolytic anemia occurring due to platelet and von Willebrand factor deposition and hyaline thrombi formation in arterioles and capillaries throughout the body, which results in organ ischemia. TTP can be idiopathic or secondary, and there are several causes of secondary TTP. There is a clinical syndrome resembling TTP that occurs after surgical procedures, so-called "postoperative TTP" (pTTP). In this review, the differential diagnosis, pathogenesis and clinical and laboratory features of pTTP, together with the treatment modalities and outcomes of the patients, are discussed. The pTTP is a diagnosis of exclusion, and disseminated intravascular coagulation, heparin-induced thrombocytopenia and medication-induced effects should be ruled out. As in classical TTP, patients with pTTP should be diagnosed and treated with therapeutic plasma exchange (TPE) as early as possible to reduce their morbidity and mortality. Although rarely seen, surgeons and physicians of all specialties should be alert to the possibility of pTTP, and since pTTP is a life-threatening event that usually can be treated successfully with TPE, especially when diagnosed early in its course, it is critical to recognize and treat pTTP promptly.

Medical management and strategies to prevent coronary artery disease in patients with type 2 diabetes mellitus

Coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM) is associated with increased immediate and long-term mortality compared with patients without T2DM. The amplified incidence of CAD stems partly from the aggregation of multiple risk factors, such as obesity, dyslipidemia, and hypertension, which occur in this population. In addition, there appear to be increased forces at play at the molecular and vascular levels in these individuals, which is evidenced by the increased thrombosis and inflammation that is seen in those with diabetic atherosclerosis. Hence, there is a growing need to emphasize early and vigilant risk factor management in patients with T2DM to help reduce their burden of cardiovascular-related mortality. In this article, we review the primary and secondary prevention measures as well as the management of CAD in patients with T2DM.

Leucocytoclastic vasculitis as a late complication of clopidogrel therapy

We describe a case of leucocytoclastic vasculitis manifested as exanthematous rash in a 57-year-old woman on long-term therapy with clopidogrel. The diagnosis was confirmed by skin biopsy. The patient was managed symptomatically with oral antihistaminics and topical steroids in consultation with dermatologists. Clopidogrel therapy was discontinued on suspicion of drug-induced vasculitis. The rash resolved completely within 2 weeks of withdrawal of clopidogrel, satisfying criteria for a probable adverse drug reaction. Leucocytoclastic vasculitis is an unusual adverse effect of clopidogrel therapy and even rarer as a late complication.

Postoperative thrombotic thrombocytopenic purpura after aortofemoral bypass

Thrombotic thrombocytopenic purpura (TTP) is uncommon in the postoperative setting, even more so after vascular surgery. We present a case of thrombocytopenia after aortofemoral bypass, which highlights the importance of a high index of suspicion for postoperative TTP to avoid life-threatening consequences.

Ticlopidine-, clopidogrel-, and prasugrel-associated thrombotic thrombocytopenic purpura: a 20-year review from the Southern Network on Adverse Reactions (SONAR)

Thienopyridine-derivatives (ticlopidine, clopidogrel, and prasugrel) are the primary antiplatelet agents. Thrombotic thrombocytopenic purpura (TTP) is a rare drug-associated syndrome, with the thienopyridines being the most common drugs implicated in this syndrome. We reviewed 20 years of information on clinical, epidemiologic, and laboratory findings for thienopyridine-associated TTP. Four, 11, and 11 cases of thienopyridine-associated TTP were reported in the first year of marketing of ticlopidine (1989), clopidogrel (1998), and prasugrel (2010), respectively. As of 2011, the FDA received reports of 97 ticlopidine-, 197 clopidogrel-, and 14 prasugrel-associated TTP cases. Severe deficiency of ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) was present in 80% and antibodies to 100% of these TTP patients on ticlopidine, 0% of the patients with clopidogrel-associated TTP (p < 0.05), and an unknown percentage of patients with prasugrel-associated TTP. TTP is associated with use of each of the three thienopyridines, although the mechanistic pathways may differ.

Peripheral arterial disease of the lower extremities

Persons with peripheral arterial disease (PAD) are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Smoking should be stopped and hypertension, dyslipidemia, diabetes mellitus, and hypothyroidism treated. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. The serum low-density lipoprotein cholesterol should be reduced to < 70 mg/dl. Antiplatelet drugs such as aspirin or clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to persons with PAD. β-Blockers should be given if coronary artery disease is present. Cilostazol improves exercise time until intermittent claudication. Exercise rehabilitation programs should be used. Revascularization should be performed if indicated.

Anaemia in pregnancy

Anaemia in pregnancy, defined as a haemoglobin concentration (Hb) < 110 g/L, affects more than 56 million women globally, two thirds of them being from Asia. Multiple factors lead to anaemia in pregnancy, nutritional iron deficiency anaemia (IDA) being the commonest. Underlying inflammatory conditions, physiological haemodilution and several factors affecting Hb and iron status in pregnancy lead to difficulties in establishing a definitive diagnosis. IDA is associated with increased maternal and perinatal morbidity and mortality, and long-term adverse effects in the new born. Strategies to prevent anaemia in pregnancy and its adverse effects include treatment of underlying conditions, iron and folate supplementation given weekly for all menstruating women including adolescents and daily for women during pregnancy and the post partum period, and delayed clamping of the umbilical cord at delivery. Oral iron is preferable to intravenous therapy for treatment of IDA. B12 and folate deficiencies in pregnancy are rare and may be due to inadequate dietary intake with the latter being more common. These vitamins play an important role in embryo genesis and hence any relative deficiencies may result in congenital abnormalities. Finding the underlying cause are crucial to the management of these deficiencies. Haemolytic anaemias rare also rare in pregnancy, but may have life-threatening complications if the diagnosis is not made in good time and acted upon appropriately.

Therapeutic plasma exchange in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: the 10-year experience of a single center

BACKGROUND

Therapeutic plasma exchange (TPE) has been used for the treatment of patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS). We report the 10-year treatment results along with the risk factors analyses.

METHODS

Retrospective analyses were performed on patients who were treated with TPE for TTP-HUS.

RESULTS

Fifty-two patients were included. Secondary causes were identified in 38 patients (73·1%). The others were classified as idiopathic. After a median five sessions of TPE, 26 patients (50·0%) achieved remission. Remission rate in patients with idiopathic and secondary TTP-HUS was 71·4 and 42·1%, respectively. Overall 30-day mortality rate was 34·6% and median overall survival was 5·2 months. Patients with hematopoietic stem cell transplantation-associated TTP-HUS did not respond and had poor overall survival. Males had a lower remission rate than females (P = 0·009).

CONCLUSIONS

TPE was an effective treatment in patients with idiopathic TTP-HUS. Treatment results were various according to etiology and gender.

[Thrombotic microangiopathy after extracorporeal circulation: important differential diagnosis]

Thrombotic microangiopathies are characterized by platelet activation, endothelial damage, hemolysis and microvascular occlusion. This group of diseases is primary represented by thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Patients present with microangiopathic hemolytic anemia and thrombocytopenia as well as occlusion-related organ ischemia to a variable degree. A deficiency of the metalloprotease ADAMTS-13 is a major risk for acute disease manifestation as this is a regulator of unusually large von Willebrand factor (vWF) multimers, which are extremely adhesive and secreted by endothelial cells. In classical TTP an ADAMTS-13 activity below 5% is specific, whereas in other forms of thrombotic microangiopathies activity of ADAMTS-13 ranges from very low to normal. Symptoms of different forms of thrombotic microangiopathy are frequently overlapping and a clear classification according to clinical criteria is often difficult. Due to a high mortality, particularly of TTP, immediate diagnosis and therapy are essential. In this article two cases of thombotic microangiopathy after cardiac surgery are reported. After exclusion of TTP and HUS as well as other etiologies of thrombotic microangiopathy a relationship between the use of extracorporeal circulation and the pathogenesis of thrombotic microangiopathy is assumed.

Thrombotic microangiopathies: multimers, metalloprotease, and beyond

The pathophysiology of various types of thrombotic microangiopathies is coming progressively into focus. Therapeutic advances are likely to follow at a quickening pace. This discussion focuses on thrombotic thrombocytopenic purpura (TTP), the hemolytic-uremic syndrome (HUS), thrombotic microangiopathies associated with transplantation-immunosuppression or anti-angiogenesis therapy, and the preeclampsia/hemolysis-elevated liver enzymes and low platelets syndrome (HELLP).

[Hemolytic uremic syndrome in adults]

Hemolytic uremic syndrome (HUS) is related to a renal thrombotic microangiopathy, inducing hypertension and acute renal failure (ARF). Its pathogenesis involves an activation/lesion of microvascular endothelial cells, mainly in the renal vasculature, secondary to bacterial toxins, drugs, or autoantibodies. An overactivation of the complement alternate pathway secondary to a heterozygote deficiency of regulatory proteins (factor H, factor I or MCP) or to an activating mutation of factor B or C3 can also result in HUS. Less frequently, renal microthrombi are due to an acquired or a constitutional deficiency in ADAMTS-13, the protease cleaving von Wilebrand factor. Hemolytic anemia with schistocytes, thrombocytopenia without evidence of disseminated intravascular coagulation, and renal failure are consistently found. In typical HUS, a prodromal diarrhea, with blood in the stools, is observed, related to pathogenic enterobacteria, most frequently E. Coli O157:H7. HUS may also occur in the post partum period, and is then related to a factor H or factor I deficiency. HUS may also occur after various treatments such as mitomycin C, gemcitabine, ciclosporin A, or tacrolimus, and as reported more recently bevacizumab, an anti VEGF antibody. Atypical HUS are not associated with diarrhea, may be sporadic or familial, and can be related to an overactivation of the complement alternate pathway. More recently, some of them have been related to a mutation of thrombomodulin, which also regulates the alternate pathway of complement. In adults, several HUS are encountered in the course of chronic nephropathies: nephroangiosclerosis, chronic glomerulonephritis, post irradiation nephropathy, scleroderma, disseminated lupus erythematosus, antiphospholipid syndrome. Overall the prognosis of HUS has improved, with a patient survival greater than 85% at 1 year. Chronic renal failure is observed as a sequella in 20 to 65% of the cases. Plasma infusions and plasma exchanges are effective in most of the cases to treat hemolysis and thrombocytopenia. Steroid therapy is debated, as well as immunosuppressive drugs, including rituximab, in autoimmune forms. A new monoclonal anti-C5 antibody is tested, and seems to be effective in atypical HUS with abnormal complement alternate pathway activation. If terminal renal failure occurs, renal transplantation can be performed but the risk of recurrence, which very low in post infectious forms of HUS, is about 70 to 80% in genetic forms of complement regulatory protein deficiency.

Komplexe Gerinnungsstörungen

Die thrombotisch-thrombozytopenische Purpura (TTP) und das hämolytischurämische Syndrom (HUS) sind thrombotische Mikroangiopathien, gekennzeichnet durch eine Endothelzellschädigung mit nachfolgender Bildung von Thromben in der Mikrozirkulation mit intravasaler Hämolyse und Thrombozytopenie. Ischämische Organdysfunktionen im Gehirn, den Nieren und anderen Organen Prägen das klinische Bild. Während bei Erwachsenen das Auftreten einer neurologischen Symptomatik zur Diagnose TTP führt, wird bei Kindern mit dem Leitsymptom Nierenversagen die Diagnose HUS gestellt.

[Implications of the REACH registry for vascular surgery]

Because of the increase in life expectancy, peripheral artery disease (PAD) has become a major health problem. A study performed in Spain in persons aged more than 65 years old found an overall prevalence of PAD of 9.9%. The most important risk factors for PAD were smoking, diabetes mellitus, advanced age, hyperlipidemia and hypertension. Treatment includes smoking cessation, exercise, statins, platelet antiaggregants, cilostazol or hemorheologic agents, and revascularization techniques. Data from the Spanish arm of REACH indicate that the PAD subgroup shows the poorest control of blood pressure and cholesterol and that use of platelet antiaggregants and statins is lowest in these patients, indicating that therapeutic and preventive strategies are not being correctly applied.

Selecting the optimal antithrombotic regimen for patients with acute coronary syndromes undergoing percutaneous coronary intervention

The wide variety of anticoagulant and antiplatelet agents available for clinical use has made choosing the optimal antithrombotic regimen for patients with acute coronary syndromes undergoing percutaneous coronary intervention a complex task. While there is no single best regimen, from a risk-benefit ratio standpoint, particular regimens may be considered optimal for different patients. We review the mechanisms of action for the commonly prescribed antithrombotic medications, summarize pertinent data from randomized trials on their use in acute coronary syndromes, and provide an algorithm (incorporating data from these trials as well as risk assessment instruments) that will help guide the decision-making process.

Ticlopidine- and clopidogrel-associated thrombotic thrombocytopenic purpura (TTP): review of clinical, laboratory, epidemiological, and pharmacovigilance findings (1989-2008)

Thrombotic thrombocytopenic purpura (TTP) is a fulminant disease characterized by platelet aggregates, thrombocytopenia, renal insufficiency, neurologic changes, and mechanical injury to erythrocytes. Most idiopathic cases of TTP are characterized by a deficiency of ADAMTS13 (a disintegrin and metalloprotease, with thrombospondin-1-like domains) metalloprotease activity. Ironically, use of anti-platelet agents, the thienopyridine derivates clopidogrel and ticlopidine, is associated with drug induced TTP. Data were abstracted from a systematic review of English-language literature for thienopyridine-associated TTP identified in MEDLINE, EMBASE, the public website of the Food and Drug Administration, and abstracts from national scientific conferences from 1991 to April 2008. Ticlopidine and clopidogrel are the two most common drugs associated with TTP in FDA safety databases. Epidemiological studies identify recent initiation of anti-platelet agents as the most common risk factor associated with risks of developing TTP. Laboratory studies indicate that most cases of thienopyridine-associated TTP involve an antibody to ADAMTS13 metalloprotease, present with severe thrombocytopenia, and respond to therapeutic plasma exchange (TPE); a minority of thienopyridine-associated TTP presents with severe renal insufficiency, involves direct endothelial cell damage, and is less responsive to TPE. The evaluation of this potentially fatal drug toxicity can serve as a template for future efforts to comprehensively characterize other severe adverse drug reactions.

Pharmacovigilance and reporting oversight in US FDA fast-track process: bisphosphonates and osteonecrosis of the jaw

More than half of all serious adverse reactions are identified 7 or more years after a drug receives approval from the US Food and Drug Administration (FDA). In 2002, 9 months after the intravenous bisphosphonate zoledronic acid received regulatory approval for marketing, the FDA received reports of nine patients with cancer, who were treated with zoledronic acid, who unexpectedly developed osteonecrosis of the jaw. During the next 2 years, three oral surgeons described 104 patients with cancer with osteonecrosis of the jaw in the medical literature and identified intravenous bisphosphonate therapy as being common to the care of these patients. In subspecialty medical, radiology, and dental journals, case reports and case series described clinical features of osteonecrosis of the jaw in patients with cancer who were treated with bisphosphonates. Manufacturer-sponsored epidemiological studies reported the first estimates of the incidence of this toxic effect, ranging from 0.1% to 1.8%. By contrast, independent epidemiological efforts from clinicians and the International Myeloma Foundation reported incidence estimates between 5% and 10%. Between 2003 and 2005, warnings about the risks of bisphosphonate-associated osteonecrosis were disseminated by national regulatory agencies, the manufacturers of bisphosphonates, and the International Myeloma Foundation. From 2006, independent clinical recommendations for diagnosis, prevention, and treatment of this toxic effect have been disseminated by manufacturers, national regulatory authorities, the International Myeloma Foundation, and medical specialty organisations. Furthermore, independent efforts by pharmaceutical manufacturers, dental and medical professionals, a non-profit organisation (the International Myeloma Foundation), patients, and regulatory authorities has led to the rapid identification and dissemination of safety information for this serious adverse reaction. Better coordination of safety-related pharmacovigilance initiatives is now needed.

Comparison between ticlopidine and clopidogrel in patients undergoing primary stenting in acute myocardial infarction: results from the CADILLAC trial

OBJECTIVE

The aim of this article is to examine whether clopidogrel and ticlopidine treatments produce similar clinical outcomes for patients receiving primary stenting for acute myocardial infarction (AMI).

BACKGROUND

Prior studies have yielded conflicting results on the relative safety and efficacy of clopidogrel and ticlopidine after stent implantation, warranting an evaluation in primary stenting for AMI.

METHODS

In the multicenter, prospective CADILLAC trial, patients undergoing primary infarct stenting were treated at operator discretion with either ticlopidine (931 patients) or clopidogrel (163 patients) and then followed for 1 year. Baseline clinical and angiographic characteristics were comparable except for baseline TIMI 0/1 flow (72.5% clopidogrel vs. 63.9% ticlopidine, P = 0.04).

RESULTS

Patients receiving clopidogrel had more recurrent ischemia in hospital (6.1 vs. 2.8%, P = 0.02) and at 30 days (10.5 vs. 5.8%, P = 0.02), more moderate and severe bleeding at 30 days (7.4 vs. 2.7%, P = 0.002), and similar rates of stent thrombosis out to 1 year (P = 0.11). By multivariable analysis, clopidogrel use was an independent predictor for recurrent ischemia in hospital (P = 0.0002), and at 30 days (P = 0.012); and of moderate and severe bleeding in hospital (P = 0.002), and at 30 days (P = 0.001).

CONCLUSIONS

Despite thienopyridines similarities, their efficacy may be different within the first 30 days of primary stenting for AMI. A prospective, randomized trial is required to confirm these findings.

Use of antiplatelet agents for prevention of ischemic stroke

Overall management to lower risk for ischemic stroke is multifaceted. Management includes measures to treat risk factors for accelerated atherosclerosis and stroke, antithrombotic therapies to lower the risk for thromboembolism, and surgery to treat a defined arterial or cardiac lesion. Treatment decisions are made on a case-by-case basis, with most patients receiving some combination of medication and recommendations for lifestyle modification. Some patients will also undergo surgical or endovascular interventions. This article discusses antithrombotic treatment for ischemic stroke prevention, placing major emphasis on the indications for and administration of antiplatelet therapy.

Comparison of sarpogrelate and ticlopidine in bare metal coronary stent implantation

BACKGROUND

The efficacy and safety of sarpogrelate, a selective 5-hydroxytryptamine receptor subtype 2A antagonist, have not yet been established in bare metal coronary stenting. Accordingly, we sought to clarify whether treatment with sarpogrelate is clinically useful in bare metal coronary stenting.

METHODS

A total of 450 patients who underwent successfully planned or unplanned bare metal coronary stenting were randomly divided into the following 2 groups: the sarpogrelate (300 mg/day) plus aspirin (100 mg/day) group (group S, n=225) and the ticlopidine (200 mg/day) plus aspirin (100 mg/day) group (group T, n=225). Either sarpogrelate or ticlopidine was administered for at least 4 weeks after the procedure. Follow-up coronary arteriography was performed at 6 months after the procedure. The primary endpoints were the incidence of adverse drug reactions requiring a withdrawal of treatment and the rate of binary restenosis. The secondary endpoint was the incidence of stent thrombosis.

RESULTS

The incidence of adverse drug reactions requiring a withdrawal of treatment was significantly lower in group S than in group T (0.44% vs 8%, p=0.002). The rate of binary restenosis did not differ significantly between groups S and T (16.9% vs 18.2%). In addition, the incidence of subacute stent thrombosis did not differ between groups S and T (0.44% vs 0.44%).

CONCLUSIONS

The incidence of adverse drug reactions requiring a withdrawal of treatment was significantly lower with sarpogrelate use than with ticlopidine use. The rate of binary restenosis and the incidence of subacute stent thrombosis did not differ between both drug groups.