Thrombotic thrombocytopenic purpura associated with clopidogrel

Tirofiban-Induced Profound Thrombocytopenia: A Case Report

Platelet glycoprotein IIB/IIIA antagonists are potent inhibitors of platelet aggregation. Although the incidence of thrombocytopenia following their administration is relatively low, it can sometimes lead to fatal consequences. We report a case of a 57-year-old gentleman presenting with non-ST elevation myocardial infarction complicated with tirofiban-induced profound thrombocytopenia that developed within 12 hours of administration. Given the high risk of acute-onset thrombocytopenia following treatment with glycoprotein IIb/IIIa inhibitors, platelet count monitoring is highly encouraged at frequent intervals. This case highlights the importance of early detection and treatment of thrombocytopenia.

Clopidogrel-induced thrombotic microangiopathy: a case report

Thrombotic microangiopathy is a serious condition that can be precipitated by exposure to certain medications. Although rare, it is life threatening and requires a high index of clinical suspicion, appropriate laboratory testing and immediate cessation of the offending agent. We present a case of a 75-year-old man with a history of ischaemic heart disease treated with clopidogrel and aspirin. One month after initiating the treatment he developed microangiopathic haemolytic anaemia and thrombocytopenia. Extensive clinical and laboratory investigations suggested thrombotic microangiopathy secondary to clopidogrel. The drug was immediately discontinued and treatment with intravenous corticosteroids was started. Within a week the patient's laboratory parameters normalised, indicating successful recovery. This case highlights the role of early detection and immediate discontinuation of suspected medication in the effective management of clopidogrel-induced thrombotic microangiopathy. Healthcare professionals should consider drug-induced thrombotic microangiopathy as a possible diagnosis in patients receiving clopidogrel who present with thrombocytopenia and microangiopathic haemolytic anaemia.

Evaluation of clopidogrel, hypercoagulability, and platelet count in dogs undergoing splenectomy for splenic masses

Dogs that had splenectomy are predisposed to fatal thrombotic conditions, and thrombocytosis is a risk factor for post-splenectomy hypercoagulability. However, in veterinary medicine, there are no specific therapeutic approaches for managing this hypercoagulability. This study aimed to determine the preventive effect of clopidogrel on post-operative hypercoagulability during the first 2 weeks post-splenectomy in dogs with splenic masses. This study included 12 dogs that had splenectomy. Seven dogs received no treatment (group A), and five were treated with clopidogrel (group B). Clopidogrel was loaded at 10 mg/kg on day 2 and continued at 2 mg/kg until day 14. Blood samples were collected on the day of surgery and 2, 7, and 14 days after splenectomy in both groups. In group B, thromboelastography (TEG) was performed on the same days. In group A, there was significant elevation of platelet counts on days 7 (p = 0.007) and 14 (p = 0.001) compared to day 0. In group B, the platelet counts were significantly elevated on day 7 (p = 0.032) but no significant difference was found on day 14 compared to day 0. Platelet counts on day 14 were significantly higher in group A than in group B (p = 0.03). The lower platelet counts were correlated with alterations in TEG parameters, and no significant differences were found in the K and α-angle values at all postoperative assessment points compared to day 0. Our study suggests that clopidogrel may reduce post-operative thrombocytosis and hypercoagulability in dogs that undergo splenectomy for splenic masses.

A retrospective analysis of e-prescriptions for non-communicable diseases on a telehealth platform in Malaysia

BACKGROUND

The management of non-communicable diseases (NCDs) has benefited from telehealth services. As these services which include teleconsultation services and e-prescriptions are relatively new in Malaysia, the data generated provide an unprecedented opportunity to study medication use patterns for the management of NCDs in the country. We analyze e-prescriptions from a local telehealth service to identify medication use patterns and potential areas to optimize medication use in relation to clinical practice guidelines.

METHODS

A cross sectional observational study was conducted by retrieving e-prescription records retrospectively from a telehealth service. 739,482 records from January 2019 to December 2021 were extracted using a designated data collection form. Data cleaning, standardization and data analysis were performed using Python version 3.11. The diagnoses were classified according to the International Classification of Disease 10 (ICD-10), while medications were classified using the Anatomical Therapeutic Chemical (ATC) system. Diagnoses, frequency of use for medication classes and individual medications were analyzed and compared to clinical practice guidelines.

RESULTS

The top five NCD diagnoses utilized by the service were hypertension (37.7%), diabetes mellitus (25.1%), ischemic heart disease (24.3%), asthma (14.4%), and dyslipidemia (11.7%). Medications were prescribed mostly in accordance with guideline recommendations. However, angiotensin receptor blockers (ARBs) were significantly more frequently prescribed compared to angiotensin converting enzyme inhibitors (ACEIs). Several medication classes appeared underutilized, including ACEIs in hypertensive patients with diabetes or ischemic heart disease, sodium glucose cotransporter 2 inhibitors in diabetic patients with ischemic heart disease, and metformin in patients with diabetes.

CONCLUSIONS

Telehealth services are currently being utilized for the management of NCDs. Medication use for the management of NCDs through these services are mostly in accordance with guideline recommendations, but there exist areas that would warrant further investigation to ensure optimal clinical and economic outcomes are achieved.

Progress in the clinical effects and adverse reactions of ticagrelor

BACKGROUND

Ticagrelor is a novel receptor antagonist that selectively binds to the P2Y12 receptor, thereby inhibiting adenosine diphosphate (ADP)-mediated platelet aggregation. Compared to clopidogrel, ticagrelor has the advantages of a fast onset, potent effects, and a reversible platelet inhibition function, which make this drug clinically suitable for treating acute coronary syndrome (ACS), especially acute ST-segment elevation myocardial infarction (STEMI).

OBJECTIVE

This review was performed to determine the basic characteristics, clinical effects, and adverse reactions of ticagrelor.

METHODS

Relevant trials and reports were obtained from the MEDLINE, Embase, and Cochrane Library databases.

RESULTS

Ticagrelor is rapidly absorbed by the body after oral administration, exhibits inherent activity without requiring metabolic activation, and binds reversibly to the P2Y12 receptor. Ticagrelor has been recommended in ACS treatment guidelines worldwide due to its advantageous pharmacological properties and significant clinical benefits. Ticagrelor inhibits platelet aggregation, inhibits inflammatory response, enhances adenosine function, and has cardioprotective effects. However, ticagrelor also causes adverse reactions such as bleeding tendency, dyspnea, ventricular pause, gout, kidney damage, and thrombotic thrombocytopenic purpura in clinical treatment. Therefore, it is necessary to pay attention to risk assessments when using ticagrelor.

CONCLUSION

Ticagrelor is a promising drug for the effective treatment of ACS. When using ticagrelor, individualized treatment should be provided based on the specific conditions of the patients to avoid serious adverse events.

A Case Report of Quinine-Induced Thrombotic Microangiopathy Successfully Treated With Eculizumab

Drug-induced thrombotic microangiopathy (DITMA) is a life-threatening condition which may be immune or nonimmune mediated. Quinine is the most implicated drug in immune-mediated DITMA. However, the optimal treatment is unclear. Complement inhibition by eculizumab has demonstrated success in many DITMA (e.g., carfilzomib, gemcitabine, and tacrolimus), but there are limited data in DITMA, including quinine-associated cases. A 55-year-old female was diagnosed with quinine-associated thrombotic microangiopathy (TMA), as confirmed by a positive quinine-dependent platelet-associated antibody. This was successfully treated with eculizumab with complete resolution of thrombocytopenia and anemia by 1 and 6 weeks. She required hemodialysis for a month and gained full recovery of renal function. We discuss various challenges with the diagnosis and management of DITMA. We also review published data on the use of eculizumab in various DITMA. Our case demonstrates successful treatment of quinine-induced TMA with eculizumab. We recommend further studies to assess the efficacy of complement inhibition in quinine and other DITMA.

A Case of Thrombotic Thrombocytopenic Purpura and ST-Elevation Myocardial Infarction: An Unusual Correlation

Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially devastating blood disorder depicted by thrombocytopenia, fever, widespread small vessel hemolytic anemia, and neurological symptoms. The involvement of the renal and neurological systems is frequently reported in TTP; however, TTP-induced acute coronary syndrome is not widely reported. We describe a case of myocardial infarction induced by TTP in a patient who presented with the typical manifestation of acute coronary syndrome. Echocardiogram revealed a myocardial injury, and detailed investigations revealed increased levels of troponin I, lactate dehydrogenase, diminished levels of haptoglobin and von Willebrand factor-cleaving protease, and schistocytes on peripheral smear, suggestive of TTP-induced myocardial infarction. His condition was stabilized after commencing plasmapheresis, steroids, and rituximab. The initial steps in the management of this patient involve the prompt administration of steroids and the urgent start of plasmapheresis to increase platelet count.

Use of Japanese big data from electronic medical records to investigate risk factors and identify their high-risk combinations for linezolid-induced thrombocytopenia

PURPOSE

Thrombocytopenia is a major event associated with linezolid (LZD) therapy. Factors affecting LZD-induced thrombocytopenia (LIT) have been reported in previous studies. However, several issues pertaining to LIT have not yet been clarified. In the present study, we used Japanese big data to investigate associated factors and their high-risk combinations that influence LIT.

METHODS

Patients administered LZD between May 2006 and October 2020 were included in this study. LIT was defined as either a 30% or more reduction from the baseline platelets or platelet values of < 100,000/µL. We evaluated factors affecting LIT and combinations of factors that alter LIT risk according to a decision tree (DT) analysis, a typical machine learning method.

RESULTS

We successfully enrolled 1399 patients and LIT occurred in 44.7% of the patients (n = 626). We classified the laboratory data on renal function, LZD duration, age, and body weight (BW) into smaller categories. The results of multivariate analysis showed that prolonged LZD therapy, BW < 45 kg, estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m², and dialysis were risk factors for LIT. The DT analysis revealed that the highest risk was a combination of LZD duration ≥ 14 days and eGFR < 30 mL/min/1.73 m².

CONCLUSIONS

The present study extracted four risk factors and identified high-risk combinations for LIT. Patients with these risk factors should be closely monitored.

Non-ST-Segment Elevation Myocardial Infarction As Initial Thrombotic Event of Thrombotic Thrombocytopenic Purpura: A Rare Challenging Case

Thrombotic thrombocytopenic purpura (TTP) is a rare autoimmune and devastating blood disorder that results in micro-clots throughout the body, leading to tissue damage and organ dysfunction resulting in widespread microangiopathic hemolytic anemia, thrombocytopenia, fever, and neurological symptoms. TTP patients commonly manifest renal and neurological symptoms; however, cardiovascular involvement is not widely reported in the literature. We report a case of non-ST-segment elevation myocardial infarction (NSTEMI) as an initial manifestation of TTP. Although rare, TTP complications must be considered among other possible causes of unexpected thrombocytopenia during acute phase treatment of acute coronary syndrome because of high morbidity and mortality.

Drug‐induced thrombotic thrombocytopenic purpura: A systematic review and review of European and North American pharmacovigilance data

Many medications have been reported to be associated with thrombotic thrombocytopenic purpura (TTP) through pharmacovigilance data and published case reports. Whilst there are existing data available regarding drug-induced thrombotic microangiopathy, there is no available synthesis of evidence to assess drug-induced TTP (DI-TTP). Despite this lack of evidence, patients with TTP are often advised against using many medications due to the theoretical risk of DI-TTP. This systematic review evaluated the evidence for an association of medications reported as potential triggers for TTP. Of 5098 records available 261 articles were assessed further for eligibility. Fifty-seven reports, totalling 90 patients, were included in the final analysis. There were no cases where the level of association was rated as definite or probable, demonstrating a lack of evidence of any drug causing DI-TTP. This paucity of evidence was also demonstrated in the pharmacovigilance data, where 613 drugs were reported as potential causes of TTP without assessment of the strength of association. This systematic review demonstrates the need for standardised reporting of potential drugs causing TTP. Many reports omit basic information and, therefore, hinder the chance of finding a causative link if one exists.

Davids versus Goliaths: Pharma and academia threats to individual scientists and clinicians

Background

We previously described experiences of clinicians who published adverse drug reaction reports. We now report on threats and intimidations leveled against clinicians and scientists who received publicly documented threats after communicating safety, efficacy, or data integrity findings contrary to corporate interests.

Methods

Data on threats and intimidations were obtained from transcripts of governmental hearings or agencies, university-affiliated reports, media interviews, and investigative journalism articles. Content and timing of threats and intimidation, subsequent harms, numbers of persons seriously injured or who died from individual toxicities, financial payments from sponsors related to safety, efficacy, or data integrity concerns, and civil settlements and criminal findings were evaluated.

Findings

Twenty-six individuals who communicated safety, efficacy, or data integrity concerns were targets of threats and intimidation from corporate employees (twenty-three individuals) or regulatory personnel (three). Seventeen individuals identified instances where pharmaceutical sponsors submitted fraudulent data in support of regulatory approval of a drug or device. Scientist and clinician communications were followed by drug/device withdrawals (fourteen drugs/devices), black box warnings (six drugs), withdrawal of a sponsor’s application for regulatory approval (one device), and delay of approval of a sponsor’s application for regulatory approval (one drug). Actions mainly occurred after persons communicated with pharmaceutical employees (fourteen). Intimidation efforts by corporate personnel included threats of lawsuits (eighteen individuals), hiring private investigators (nine), and public disparagement at conferences (eleven). Related intimidation efforts carried out by academia or regulatory agency superiors included threats of: loss of positions (six), loss of grant funding (two), delays in decisions regarding tenure (two); or reassignment to a low-level position (one). Academic harms included lost: hospital or university appointments (nine and six, respectively), grant funding (two), chairperson title of an international clinical trial group (one), and journal editorial board position (one). Corporate harms included payment of $1 million to defense attorneys in three cases filed against clinicians.

Interpretation

Threats and intimidation carried out by corporate employees and/or academic supervisors followed public communication of concerns regarding patient safety, drug efficacy, or data integrity, including instances where sponsors were identified as having submitted fraudulent data to regulatory or government agencies. Consideration should be given to filing criminal charges against pharmaceutical executives who are discovered by scientists or clinicians to have knowingly submitted fraudulent data to regulatory or governmental agencies, rather than causing the scientists and clinicians who submit such reports to risk losing their reputations and occupations.

ST-Segment-Elevation Myocardial Infarction Unmasking Underlying Systemic Lupus Erythematosus or Representing Thrombotic Thrombocytopenic Purpura? Report of a Challenging Case

Thrombotic thrombocytopenic purpura (TTP) is a multisystem disorder that frequently manifests itself with renal and neurological involvements. Cardiac involvement, however, has been rarely reported. In this report, we present a rare case of acquired TTP with acute myocardial infarction (AMI) as the initial manifestation. Although AMI was successfully managed by percutaneous coronary intervention, the patient developed hemolytic anemia, fever, marked thrombocytopenia, oliguria, and renal dysfunction, requiring treatment with plasma exchange and corticosteroids. TTP, albeit extremely rare, should be considered in cases with unexpected thrombocytopenia during acute-phase treatment for AMI as it can be highly lethal if not treated immediately.

Neurological complications of cardiovascular drugs

Cardiovascular drugs are used to treat arterial hypertension, hyperlipidemia, arrhythmias, heart failure, and coronary artery disease. They also include antiplatelet and anticoagulant drugs that are essential for prevention of cardiogenic embolism. Most neurologic complications of the cardiovascular drugs are minor or transient and are far outweighed by the anticipated benefits of treatment. Other neurologic complications are more serious and require early recognition and management. Overtreatment of arterial hypertension may cause lightheadedness or fatigue but often responds readily to dose adjustment or an alternative drug. Other drug complications may be more troublesome as in myalgia associated with statins or headache associated with vasodilators. The recognized bleeding risk of the antithrombotics requires careful calculation of risk/benefit ratios for individual patients. Many neurologic complications of cardiovascular drugs are well documented in clinical trials with known frequency and severity, but others are rare and recognized only in isolated case reports or small case series. This chapter draws on both sources to report the adverse effects on muscle, nerve, and brain associated with commonly used cardiovascular drugs.

Clinicopathological features of cutaneous and renal glomerular vasculopathy in 178 dogs

BACKGROUND

One hundred seventy-eight dogs with cutaneous and renal glomerular vasculopathy (CRGV) were evaluated to further the understanding of the natural course of CRGV. CRGV, a form of thrombotic microangiopathy, can cause skin lesions and potentially acute kidney injury (AKI) with a high mortality rate.

METHODS

Cases were submitted from multiple practices from 2012 until June 2019. Clinical histories and laboratory data were reviewed to describe the features of CRGV.

RESULTS

Most cases (91%) occurred between November and May. Fifteen dogs (8.4%) with CRGV were in contact with another dog that developed skin lesions +/- AKI. Limb lesions were present on 144 dogs (80.9%) at presentation. Median time from appearance of a lesion to AKI was 3 days (range -4-45 days). Neurological signs occurred in 33 dogs (18.6%) including at presentation in 2 (1.1%). Systemic signs were present in 13 dogs prior to a skin lesion (7.3%). Non-steroidal anti-inflammatory drugs were prescribed prior to AKI identification in 92 of 170 dogs (54.1%). Thrombocytopenia was present in 115 of 137 (83.9%) of dogs.

CONCLUSION

The timeframe over which AKI may develop is longer than previously reported, neurological signs can be identified at presentation or during hospitalisation, and thrombocytopenia is even more common than previously reported.

Clopidogrel Hypersensitivity: Pathogenesis, Presentation and Diagnosis

This paper provides an overview of the pathogenesis, presentation and diagnosis of clopidogrel hypersensitivity. The majority of clopidogrel hypersensitivity cases are due to a T cell mediated Gell and Coombs Type IV reaction. History, histology, and patch testing have shown consistency with a T cell mediated mechanism. Clopidogrel reactions most commonly present as a mild delayed maculopapular erythematous rash 5 to 10 days after introduction of the drug, and do not always require discontinuation of the drug. Severe cutaneous, systemic, and immediate adverse reactions to clopidogrel are rare. For the diagnosis of clopidogrel hypersensitivity, drug causality can be determined using patch testing, or for mild reactions, recurrence of symptoms after drug reintroduction, although neither are required for diagnosis.

[Current antiplatelet agents, new inhibitors and therapeutic targets]

Cardiovascular diseases are the leading cause of deaths in the world. Platelets play a major role in the occurrence of these diseases and the development of antiplatelet drugs is a priority in the fight against cardiovascular diseases-associated mortality. Aspirin and thienopyridine-based P2Y12 inhibitors are the main drugs currently used. These molecules target the initiation of platelets activation and are responsible for a moderate inhibitory action. Other antiplatelet agents, as glycoprotein (GP) IIb/IIIa antagonists, inhibit platelet aggregation independently of initial activation-associated pathways, but are responsible for increased hemorrhagic events. Regarding each antiplatelet agent's specific characteristics, the prescription of these drugs must take into account the type of cardiovascular event, the age of the patient, the past medical history, and the potential hemorrhagic adverse events. Thus, there is a need for the development of new molecules with a more targeted effect, maintaining optimal efficiency but with a reduction of the hemorrhagic risk, which is the principal limitation of these treatments.

Association of ABCB1 Gene Polymorphisms and Clopidogrel Responsiveness in Iranian Patients undergoing Percutaneous Coronary Intervention

Clopidogrel is an antiplatelet agent currently used for preventing stent thrombosis. Despite certain clinical benefits of clopidogrel in patients undergoing percutaneous coronary intervention (PCI), adequate antiplatelet effect has not been obtained in some patients. The present study was designed to investigate the potential association of ABCB1 (ATP-Binding Cassette, Subfamily B, member1) gene polymorphism, and clopidogrel responsiveness in Iranian patients after PCI. Sixty-seven patients were included in the study. Blood samples were taken from patients at baseline, 2 h after administration of 600-mg loading dose of clopidogrel, 24 h and 30 days after PCI. Platelet aggregation was measured by light transmittance aggregometry (LTA) with two levels of adenosine diphosphate (ADP) concentrations (5 and 20 µM). ABCB1 genotyping was performed by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). The allelic frequencies of wild type, heterozygote, and homozygote genotypes of ABCB1 were 20.9%, 74.6%, and 4.5%, respectively. There was no significant association between polymorphism of ABCB1 and clopidogrel non-responsiveness (P > 0.05) in various situations. No significant difference was observed for demographic characteristics. Genetic and demographic factors had no significant effect on the platelet activity of clopidogrel in an Iranian population.

Cutaneous and Renal Glomerular Vasculopathy: What Do We Know so Far?

Cutaneous renal glomerular vasculopathy (CRGV), colloquially named "Alabama rot," is an emerging condition in the United Kingdom, previously reported from the United States and Germany. The cause of CRGV is not yet determined; no definitive link to an infectious agent has been made. Dogs diagnosed with CRGV initially develop cutaneous lesions, and a proportion of these dogs go on to manifest acute kidney injury, which may result in oligoanuric acute renal failure. Antemortem diagnosis is challenging given the lack of a specific diagnostic test, and confirmation of CRGV is therefore currently dependent on identification of thrombotic microangiopathy on renal histopathology.

Validated liquid chromatography-tandem mass spectrometry method for quantification of ticagrelor and its active metabolite in human plasma

A rapid, simple and sensitive LC-MS/MS method was established and validated for simultaneous quantification of ticagrelor and its active metabolite AR-C124910XX in human plasma. After plasma samples were deproteinized with acetonitrile, the post-treatment samples were chromatographed on a Dikma C₁₈ column interfaced with a triple quadrupole tandem mass spectrometer. Electrospray negative ionization mode and multiple reaction monitoring were adopted to assay ticagrelor and AR-C124910XX. Acetonitrile and 5 mΜ ammonium acetate was used as the mobile phase with a gradient elution at a flow rate of 0.5 mL/min. The method was linear in the range of 0.781-800 ng/mL for both ticagrelor and AR-C124910XX with a correlation coefficient ≥0.994. The intra- and inter-day precisions were within 12.61% in terms of relative standard deviation and the accuracy was within ±7.88% in terms of relative error. The LC-MS/MS method was fully validated for its sensitivity, selectivity, stability, matrix effect and recovery. This convenient and specific LC-MS/MS method was successfully applied to the pharmacokinetic study of ticagrelor and AR-C124910XX in healthy volunteers after an oral dose of 90 mg ticagrelor.

A Review of Antiplatelet Activity of Traditional Medicinal Herbs on Integrative Medicine Studies

Thrombotic events mainly occurred by platelet activation and aggregation. The vascular occlusion causes serious disease states such as unstable angina, ischemic stroke, and heart attack. Due to the pervading of thrombotic diseases, new antiplatelet drugs are necessary for preventing and treating arterial thrombosis without adverse side effects. Traditional medicinal herbs have been used for the treatment of human ailments for a long time. The clinically useful and safe products from traditional medicinal herbs were identified and developed in numerous pharmacological approaches. A complementary system of traditional medicinal herbs is a good candidate for pharmacotherapy. However, it still has a limitation in its function and efficacy. Thus, it is necessary to study the mode of action of traditional medicinal herbs as alternative therapeutic agents. In this review, we focused on our current understanding of the regulatory mechanisms of traditional medicinal herbs in antiplatelet activity and antithrombotic effect of traditional medicinal herbs on platelet function.

Proteolytic inactivation of ADAMTS13 by plasmin in human plasma: risk of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is caused by inactivation of a von Willebrand factor (VWF)-cleaving enzyme, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), which leads to platelet-rich thrombi comprising unusually large VWF multimers. We have found that ADAMTS13 can bind to the inactivated form of plasmin. In addition, plasmin cleaves purified ADAMTS13 into several fragments and inactivates it. Hence, we hypothesized that activation of plasminogen to plasmin becomes a new-onset factor for TTP due to ADAMTS13 inactivation. Plasmin was added exogenously or activated from plasminogen by streprokinase addition in human plasma (HP). ADAMTS13 digestion and effects of the digestion on ADAMTS13 activity were evaluated. Exogenous plasmin cleaved ADAMTS13 into several fragments, but a portion of ADAMTS13 remained in full-length form. Digestion profile of ADAMTS13 with streprokinase added exogenously in HP was similar to that of ADAMTS13 with exogenous plasmin. ADAMTS13 activity measured using FRETS-VWF73 decreased to ∼40% compared with that for normal plasma. Endogenous VWF multimer-cleaving activity was attenuated more severely (∼10%). These data suggest that endogenous plasmin cleaves ADAMTS13 into fragments and reduces its activity to ∼10%. We suggest that endogenous plasmin activation alone is not sufficient to cause TTP, but plasmin activation with ADAMTS13 deficiency might increase the risk of TTP onset.

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.

Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP; also known as Moschcowitz disease) is characterized by the concomitant occurrence of often severe thrombocytopenia, microangiopathic haemolytic anaemia and a variable degree of ischaemic organ damage, particularly affecting the brain, heart and kidneys. Acute TTP was almost universally fatal until the introduction of plasma therapy, which improved survival from <10% to 80-90%. However, patients who survive an acute episode are at high risk of relapse and of long-term morbidity. A timely diagnosis is vital but challenging, as TTP shares symptoms and clinical presentation with numerous conditions, including, for example, haemolytic uraemic syndrome and other thrombotic microangiopathies. The underlying pathophysiology is a severe deficiency of the activity of a disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13), the protease that cleaves von Willebrand factor (vWF) multimeric strings. Ultra-large vWF strings remain uncleaved after endothelial cell secretion and anchorage, bind to platelets and form microthrombi, leading to the clinical manifestations of TTP. Congenital TTP (Upshaw-Schulman syndrome) is the result of homozygous or compound heterozygous mutations in ADAMTS13, whereas acquired TTP is an autoimmune disorder caused by circulating anti-ADAMTS13 autoantibodies, which inhibit the enzyme or increase its clearance. Consequently, immunosuppressive drugs, such as corticosteroids and often rituximab, supplement plasma exchange therapy in patients with acquired TTP.

Syndromes of Thrombotic Microangiopathy

Thrombotic thrombocytopenia purpura (TTP) and the hemolytic uremic syndrome (HUS) are rare thrombotic microangiopathies that can be rapidly fatal. Although the acquired versions of TTP and HUS are generally highest on this broad differential, multiple rarer entities can produce a clinical picture similar to TTP/HUS, including microangiopathic hemolysis, renal failure, and neurologic compromise. More recent analysis has discovered a host of genetic factors that can produce microangiopathic hemolytic syndromes. This article discusses the current understanding of thrombotic microangiopathy and outlines the pathophysiology and causative agents associated with each distinct syndrome as well as the most accepted treatments.

Pernicious Anemia Associated Cobalamin Deficiency and Thrombotic Microangiopathy: Case Report and Review of the Literature

A 43-year-old Hispanic male without significant previous medical history was brought to emergency department for syncope following a blood draw to investigate a 40 lbs weight loss during the past 6 months associated with decreased appetite and progressive fatigue. The patient also reported a 1-month history of jaundice. On examination, he was hemodynamically stable and afebrile with pallor and diffuse jaundice but without skin rash or palpable purpura. Normal sensations and power in all extremities were evident on neurological exam. Presence of hemolytic anemia, schistocytosis, thrombocytopenia, and elevated lactate dehydrogenase (LDH) was suggestive of thrombotic thrombocytopenic purpura (TTP). However, presence of leukopenia, macrocytes, and an inadequate reticulocyte response to the degree of anemia served as initial clues to an alternative diagnosis. Two and one units of packed red blood cells were transfused on day 1 and day 3, respectively. In addition, one unit of platelets was transfused on day 2. Daily therapeutic plasma exchange (TPE) was initiated and continued until ADAMTS-13 result ruled out TTP. A low cobalamin (vitamin B12) level was evident at initial laboratory work-up and subsequent testing revealed positive intrinsic factor-blocking antibodies supporting a diagnosis of pernicious anemia with severe cobalamin deficiency. Hematological improvement was observed following vitamin B12 supplementation. The patient was discharged and markedly improved on day 9 with outpatient follow-up for cobalamin supplementation.

The Top 12 Advances in Vascular Medicine

In the past decade, impressive strides have been made in the diagnosis and management of atherosclerotic, aneurysmal, and thromboembolic diseases, thanks in large part to the explosive growth in both vascular biology and clinical vascular medicine. We review what we consider to be the top 12 advances in this field: the discovery of nitric oxide, the metabolic syndrome, new thrombophilic disorders, therapeutic angiogenesis, endoluminal treatment of chronic venous disease, and a variety of drugs, including sildenafil, cilostazol, low-molecular-weight heparins, oral direct thrombin inhibitors, clopidogrel, statins, and angiotensin-converting enzyme inhibitors and angiotensin-receptor blocking agents.

The effect of in-hospital acquired thrombocytopenia on the outcome of patients with acute coronary syndromes: A systematic review and meta-analysis

BACKGROUND

In-hospital acquired thrombocytopenia (TP) is relatively common among patients hospitalized with acute coronary syndromes (ACS). However, its effect on short-term and long-term outcomes has yet to be reviewed systematically.

METHODS

We conducted a systematic review and meta-analysis of clinical studies assessing the relationship between new-onset in-hospital TP and adverse outcomes among ACS patients. MEDLINE, Scopus and the Cochrane Library were searched for eligible studies published before March 20, 2016.

RESULTS

Ten studies reporting on a total of 142,161 ACS patients were identified. 8133 patients showed evidence of new-onset TP during the course of their hospitalization. Compared with patients with normal platelet counts, patients with new-onset TP had a prolonged in-hospital stay, significantly higher risk of both short-term mortality (<30days) (Odds ratio (OR) [95% confidence interval (CI)]: 5.58 [3.63-8.57]) and late death (6months to 1year) (OR [95% CI]: 3.45 [2.35-5.07]), as well as a significantly higher risk of major bleeding events in the first 30days (OR [95% CI]: 6.93 [5.13-9.38]). In addition, risk for other secondary cardiovascular endpoints, including recurrent myocardial infarction, stroke, in-hospital heart failure, stent thrombosis and unplanned revascularization was also significantly higher in the TP versus the no TP group.

CONCLUSIONS

Development of TP during the in-hospital management of ACS patients is a significant predictor of both short- and long-term adverse events, including mortality. In the light of this evidence, clinicians should be cautious and closely monitor abnormal platelet counts that present early following an ACS.

Proteasome inhibitor associated thrombotic microangiopathy

A variety of medications have been implicated in the causation of thrombotic microangiopathy (TMA). Recently, a few case reports have emerged of TMA attributed to the proteasome inhibitors (PI) bortezomib and carfilzomib in patients with multiple myeloma. The aim of this case series was to better characterize the role of PI in the etiology of drug-induced TMA. We describe eleven patients from six medical centers from around the world who developed TMA while being treated with PI. The median time between medication initiation and diagnosis of TMA was 21 days (range 5 days to 17 months). Median laboratory values at diagnosis included hemoglobin-7.5 g dL(-1) , platelet count-20 × 10(9) /L, LDH-698 U L(-1) , creatinine-3.12 mg dL(-1) . No patient had any other cause of TMA, including ADAMTS13 inhibition, other malignancy or use of any other medication previously associated with TMA. Nine patients had resolution of TMA without evidence of hemolysis after withdrawal of PI. Two patients had stabilization of laboratory values but persistent evidence of hemolysis despite medication withdrawal. One patient had recurrence of TMA with rechallenge of PI. There is a strong level of evidence that PI can cause DITMA. In evaluating patients with suspected TMA, PI use should be recognized as a potential etiology, and these medications should be discontinued promptly if thought to be the cause of TMA. Am. J. Hematol. 91:E348-E352, 2016. © 2016 Wiley Periodicals, Inc.

Suicide attempt with clopidogrel

We report the case of a 49-year-old male who took an overdose of 1650 mg of clopidogrel with suicidal intend. The patient developed abnormalities of platelet aggregation, but never developed symptoms. Clopidogrel is a commonly prescribed drug. Reports of overdose of clopidogrel were very rarely reported in the literature.

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.

Thrombocytopenia in Critical Care Patients

Thrombocytopenia is a common laboratory finding in the intensive care unit (ICU) patient. Because the causes can range from laboratory artifact to life-threatening processes such as thrombotic thrombocytopenic purpura (TTP), identifying the cause of thrombocytopenia is important. In the evaluation of the thrombocytopenia patient, one should incorporate all clinical clues such as why the patient is in the hospital, medications the patient is on, and other abnormal laboratory findings. One should ensure that the patient does not suffer from heparin-induced thrombocytopenia (HIT) or one of the thrombotic microangiopathies (TMs). HIT can present in any patient on heparin and requires specific testing and antithrombotic therapy. TMs cover a spectrum of disease ranging from TTP to pregnancy complications and can have a variety of presentations. Management of disseminated intravascular coagulation depends on the patient’s condition and complication. Other causes of ICU thrombocytopenia include sepsis, medication side effects, post-transfusion purpura, catastrophic anti phospholipid antibody disease, and immune thrombocytopenia.

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.

Antiplatelet therapy - a summary for the general physicians

Platelets play a very important role in physiological haemostasis and thrombus formation. Platelet aggregation is the key pathophysiological factor in the development of arterial ischaemic events, including coronary artery disease, cerebrovascular accidents and peripheral arterial disease. As such, antiplatelet therapy plays a very important role in preventing recurrent events in the individuals who are affected by one of these conditions. Until recently, the repertoire of antiplatelet therapy was limited to aspirin and clopidogrel. However, this landscape has changed dramatically with the advent of newer and more potent agents, prasugrel and ticagrelor and also the glycoprotein IIb/IIIa antagonists. This armamentarium is likely to expand further with the advent of protease-activated receptor-1 antagonists and the intravenous cangrelor. This review summarises the different agents available and some practical considerations for their use from a general physician's perspective.

Clopidogrel-induced Thrombotic Microangiopathy in a Patient with Hypocomplementemia

Clopidogrel was administered to a 67-year-old Japanese man to prevent the recurrence of cerebral infarction. Twelve weeks later, he was admitted to our hospital with acute renal failure, hemolytic anemia and thrombocytopenia, and was diagnosed with clopidogrel-induced thrombotic microangiopathy. Clopidogrel was immediately discontinued and corticosteroid and plasma exchange therapy were administered simultaneously. Thereafter, the patient's condition gradually improved. The patient had a decreased serum complement C3 level. This suggests that the activated alternative pathway is related to thrombotic microangiopathy (TMA). TMA is a critical drug-associated adverse reaction that clinicians should always be vigilant about, because clopidogrel is widely prescribed.

Clopidogrel-Associated Thrombotic Thrombocytopenic Purpura following Endovascular Treatment of Spontaneous Carotid Artery Dissection

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening multisystem disease secondary to platelet aggregation. We present a patient who developed profound thrombocytopenia and anemia 8 days following initiation of therapy with clopidogrel after stent placement for carotid artery dissection. She did not have a disintegrin and metalloproteinase with thrombospondin domain 13 (ADAMTS 13) deficiency. Management included steroids and therapeutic plasma exchange. Clopidogrel has rarely been associated with TTP. Unlike other causes of acquired TTP, the diagnosis of early clopidogrel-associated TTP is largely clinical given the infrequent reduction in ADAMTS 13 activity.

Anti-platelet activity of water dispersible curcuminoids in rat platelets

Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10-30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two-fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A2 , serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12-lipoxygenase activity and formation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti-platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders.

Ischemic Cardiomyopathy with a Rapid Progression from Thrombotic Thrombocytopenic Purpura

An 83-year-old woman who complained of dizziness and nausea visited our hospital. An electrocardiogram showed ST-segment elevation in multiple leads and an echocardiogram showed severe hypokinesis of the anteroseptal wall of the left ventricle. However, emergency coronary angiography showed no stenotic lesions in any coronary arteries. A laboratory examination showed thrombocytopenia, renal dysfunction, and hemolysis. We therefore diagnosed the patient with thrombotic thrombocytopenic purpura (TTP). While we were preparing to initiate plasma exchange therapy, she suddenly developed cardiopulmonary arrest. A postmortem examination revealed microthrombi in the small vessels of the myocardium. We herein report a case of ischemic cardiomyopathy with a rapid progression from TTP.

Long-term outcomes associated with hospital acquired thrombocytopenia among patients with non-ST-segment elevation acute coronary syndrome

BACKGROUND

Acquired thrombocytopenia after a non-ST-segment-elevation-acute coronary syndrome (NSTE-ACS) has been associated with increased in-hospital mortality and hemorrhagic complications, but longer term outcomes are unclear. We examined the association between thrombocytopenia and long-term outcomes after accounting for thrombocytopenia severity and discharge medication use.

METHODS

Data from 7,435 NSTE-ACS patients enrolled in the SYNERGY trial were analyzed. Severe thrombocytopenia was defined as a nadir platelet count <100 × 10(9)/L or a ≥ 50% drop from baseline. Mild thrombocytopenia was defined as a nadir platelet count between 100 and 149 × 10(9)/L with a <50% drop from baseline. The primary outcomes of interest were in-hospital GUSTO moderate-severe bleeding and 1-year mortality.

RESULTS

Overall, 675 patients (9.1%) developed mild thrombocytopenia and 139 patients (1.9%) developed severe thrombocytopenia. In-hospital bleeding risks were higher in patients with mild (7.7%, adjusted HR 1.63, 95% CI 1.16-2.29) or severe (28.2%, adjusted HR 6.93, 95% CI 4.55-10.56) thrombocytopenia than in patients without thrombocytopenia (5.2%). One-year mortality rates were 6.5%, 8.1%, and 28.1% among patients with no, mild, and severe thrombocytopenia, respectively (log rank P < 0.001) but only severe thrombocytopenia remained significantly associated with increased mortality after adjustment: HR 4.07, 95% CI 2.86-5.78. Patients who developed severe thrombocytopenia were less likely to be discharged on guideline-recommended antiplatelet therapy. The relationship between severe thrombocytopenia and mortality was attenuated by but persisted after adjusting for discharge medication use (HR 2.83, 95% CI 1.49-5.38).

CONCLUSIONS

Thrombocytopenia occurs commonly during the course of NSTE-ACS care; even mild decreases are associated with clinically meaningful bleeding. Patients who developed severe thrombocytopenia were less likely to be discharged on guideline-recommended antiplatelet therapy; this may contribute to their higher associated long-term mortality.

Prognostic significance of post percutaneous coronary intervention thrombocytopenia

Several definitions of post percutaneous coronary intervention (PCI) thrombocytopenia (TC) were formulated. Recent studies demonstrated that a relative drop in platelet count ≥ 25% is the most appropriate criterion. By this definition a population is detected that is exposed not only to increased risk of hemorrhagic complications but also to increased risk of ischemic events, which may appear a paradox. In patients with acute coronary syndromes undergoing PCI, several conditions might be associated with TC: cardiopulmonary by-pass and the presence of extra corporeal membrane oxygenators, intra aortic balloon pump (IABP), cardiogenic shock, thrombolytic drugs and anticoagulant or antiplatelet drugs. Several studies demonstrated that TC and ischemic outcomes are related although it is unclear whether this is a direct relationship or TC is just a secondary effect of another cryptic protagonist. It is suggested that further investigations determine whether there is a real link between TC, a probably well defined covariate, and ischemic outcomes or whether IABP is the joining link between these two variables and whose presence needs in any case be considered in multivariable statistics. Post-PCI TC could be only a secondary effect of IABP use. On turn, the prolonged use of heparin necessarily accompanying the use of IABP, and producing a paradoxical pro-thrombotic TC, might also be implicated.