Diagnosis and management of thrombotic thrombocytopenic purpura (TTP) in Australia: findings from the first 5 years of the Australian TTP/thrombotic microangiopathy registry

Characterization of bleeding in thrombotic thrombocytopenic purpura in the precaplacizumab era: a retrospective nationwide analysis

Background

The addition of caplacizumab to immune thrombotic thrombocytopenia (iTTP) treatment options has led to a renewed interest in characterizing the epidemiology and risk factors for bleeding in iTTP. Limited data exist on the bleeding risk in iTTP due to systemic underreporting in earlier cohorts.

Objectives

To describe the incidence, patterns, and predictors of bleeding in hospitalized iTTP patients independent of caplacizumab use.

Methods

We retrospectively analyzed the National Inpatient Sample database (2012-2019) and identified adult patients with a diagnosis of iTTP. Predictors of bleeding were determined by multivariable logistic regression analysis.

Results

We identified 3103 iTTP hospitalizations; bleeding occurred in 594 (19.1%), and 157 (5.1%) were characterized by major bleeding. Mucocutaneous bleeding (7.6%) was the most frequent type of bleeding and included heavy menstrual bleeding (2.6%), gingival (2.3%), epistaxis (1.4%), and skin/procedure-related bleeding (1.3%). This was followed closely by gastrointestinal bleeding (5.6%). Patients with bleeding were more likely to be Hispanic, have a weekend admission, and have a higher prevalence of comorbidities. In the multivariable analysis, Hispanic race (odds ratio [OR], 1.48; 1.14-1.91), Asian/Pacific Islander/Native American race (OR, 2.04; 1.51-2.76), coronary artery disease (OR, 1.70; 1.38-2.11), heart failure (OR, 1.39; 1.13-1.72), autoimmune disease (OR, 2.61; 2.08-3.26), Charlson Comorbidity Index ≥ 3 (OR, 2.08; 1.66-2.61), weekend admission (OR, 1.45; 1.22-1.72), and delay ≥2 days in plasma exchange initiation (OR, 1.63; 1.38-1.92), were significantly associated with major bleeding.

Conclusions

Bleeding is a relatively common issue in acute iTTP that has not been adequately addressed in existing literature. Further studies are needed to elucidate this risk and associated factors, especially given the incorporation of caplacizumab in the treatment of iTTP.

Main features of ischemic stroke in patients with acute immune-mediated thrombotic thrombocytopenic purpura

BACKGROUND

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a microangiopathy often characterized by acute neurological involvement including ischemic stroke (IS). The characteristics of IS in iTTP remain largely unknown.

AIMS

To evaluate the epidemiology, neuroimaging patterns and risk factors of IS in iTTP patients.

METHODS

We performed a cross-sectional study of patients enrolled in the Milan TTP Registry presenting with neurological signs/symptoms and underwent neuroimaging evaluation during their first acute iTTP episode.

RESULTS

Seventy-eight patients were enrolled, the majority of patients were female (72 %), with a median age of 46 years. Computed tomography (CT) was performed in all patients, and magnetic resonance (MRI) was performed in 38 % of patients. IS was confirmed in 18 out of 78 patients (23 %), most of whom (70 %) showed a non-lacunar pattern with multifocal involvement. In the subgroup of patients who had MRI (n = 30), IS was identified in 12 patients (40 %) and of them 6 (50 %) had a false negative result with CT scan. Patients with IS were slightly older than those without, whereas the prevalence of cardiovascular risk factors and iTTP-related parameters were comparable between the two groups.

CONCLUSION

23 % of patients presenting with neurological manifestations at their first acute TTP episode, showed brain IS. As expected, MRI showed higher sensitivity in detecting ischemic lesions underscoring its usefulness over CT in this setting. An unexpected prevalence of non-lacunar and multifocal stroke patterns warrants further investigation. Cardiovascular risk factors and iTTP-related clinical and laboratory parameters were similarly distributed in patients with and without IS.

Identification of HLA alleles involved in immune thrombotic thrombocytopenic purpura patients from Turkey

Thrombotic thrombocytopenic purpura (TTP) is one of the rare group disorders classified as thrombotic microangiopathies (TMAs). Approximately 90% of TTP developed immune-mediation by the formation of antibodies against the enzyme ADAMTS-13. The exact cause is unknown. To establish an association between human leukocyte antigen (HLA) and autoimmune basis, as susceptibility or protection against the disease, we contributed a study aiming to evaluate the role of HLA in immune-mediated TTP (iTTP). Considering epidemiological factors such as age, sex, ethnicity, and geographical origins, we contributed the study in our country, Turkey, which consist of a very heterogeneous population. Patients' data collection was retrospectively from electronic database on two University hospitals having big therapeutic apheresis service. Control arm was healthy people registered as stem cell donors matched in terms of age and sex. The frequency of HLA-DRB1 and HLA-DQB1 alleles between acquired TTP and the control group was compared using the chi-square method. Yates correction and logistic regression were performed on these results. A total of 75 iTTP patients and 150 healthy individuals enrolled to the study. HLA-DRB1∗11, HLA-DQB1∗03, HLA-DRB1∗11:01, HLA-DRB1∗14:01, HLA-DRB1∗13:05, HLA-DRB1∗11 + HLA-DQB1∗03 allele pair and HLA-DRB1∗15 + HLA- DQB1∗06 were proved to be susceptibility allele pairs for iTTP. HLA-DRB1∗15, HLA-DRB1∗01:01, HLA-DRB1∗07:01, HLA-DRB1∗13:01, HLA-DRB1∗14:54, HLA-DQB1∗05:01, HLA-DQB1∗02:02 and HLA-DRB1∗07 + HLA-DQB1∗02 allele pair were found to be protective against iTTP. Our findings support an association with iTTP across very heterogenous populations in Turkey.

The Australian Aplastic Anaemia and other Bone Marrow Failure Syndromes Registry

The bone marrow failure syndromes (BMFS) are a diverse group of acquired and inherited diseases which may manifest in cytopenias, haematological malignancy and/or syndromic multisystem disease. Patients with BMFS frequently experience poor outcomes, and improved treatment strategies are needed. Collation of clinical characteristics and patient outcomes in a national disease-specific registry represents a powerful tool to identify areas of need and support clinical and research collaboration. Novel treatment strategies such as gene therapy, particularly in rare diseases, will depend on the ability to identify eligible patients alongside the molecular genetic features of their disease that may be amenable to novel therapy. The Australian Aplastic Anaemia and other Bone Marrow Failure Syndromes Registry (AAR) aims to improve outcomes for all paediatric and adult patients with BMFS in Australia by describing the demographics, treatments (including supportive care) and outcomes, and serving as a resource for research and practice improvement.

Immune thrombotic thrombocytopenic purpura in older patients: Results from the Spanish TTP Registry (REPTT)

Immune thrombotic thrombocytopenic purpura (iTTP) is an ultra-rare disease that seldom occurs in the elderly. Few reports have studied the clinical course of iTTP in older patients. In this study, we have analysed the clinical characteristics at presentation and response to therapy in a series of 44 patients with iTTP ≥60 years at diagnosis from the Spanish TTP Registry and compared them with 209 patients with <60 years at diagnosis from the same Registry. Similar symptoms and laboratory results were described in both groups, except for a higher incidence of renal dysfunction among older patients (23% vs. 43.1%; p = 0.008). Front-line treatment in patients ≥60 years was like that administered in younger patients. Also, no evidence of a difference in clinical response and overall survival was seen in both groups. Of note, 14 and 25 patients ≥60 years received treatment with caplacizumab and rituximab, respectively, showing a favourable safety and efficacy profile, like that observed in patients <60 years.

A Saudi multicenter experience on therapeutic plasma exchange for patients with thrombotic thrombocytopenic purpura: A call for national registry

BACKGROUND

The improvement in the clinical care for patients with thrombotic thrombocytopenic purpura (TTP) is evolving, and many efforts are being put to standardize it. Here, we aimed to assess the provided care at a national level and identify deficiencies.

METHODS

A national Saudi retrospective descriptive study was carried out at six tertiary referral centers and included all patients who underwent therapeutic plasma exchange (TPE) for the diagnosis of TTP between May 2005, and July 2022. Collected information included demographic data, clinical features on presentation, and the results of laboratory investigations at admission and discharge. In addition, the number of TPE sessions, days till the first session of TPE, usage of immunological agents, and clinical outcomes were all collected.

RESULTS

One hundred patients were enrolled, predominantly female (56%). The mean age was 36.8 years. At diagnosis, 53% of patients showed neurological involvement. The mean platelet count at presentation was 21 × 109 /L. All patients had anemia (mean hematocrit 24.2%). Schistocytes were present in the peripheral blood film of all patients. The mean number of TPE rounds was 13 ± 9.3, and the mean days to start TPE since admission for the first episode was 2.5 days. ADAMTS13 level was measured in 48% of patients and was significantly low in 77% of them. Assessing for clinical TTP scores, 83%, 1000%, 64% of eligible patients had an intermediate/high PLASMIC, FRENCH, and Bentley scores, respectively. Caplacizumab was used on only one patient, and rituximab was administered to 37% of patients. A complete response for the first episode was achieved in 78% of patients. The overall mortality rate was 25%. Neither time to TPE, the use of rituximab or steroid affected survival.

CONCLUSIONS

Our study shows an excellent response to TPE with a survival rate approximate to the reported international literature. We observed a deficiency in using validated scoring systems in addition to confirming the disease by ADAMTS13 testing. This emphasizes the need for a national registry to facilitate proper diagnosis and management of this rare disorder.

Treatment Challenges of Acquired Thrombotic Thrombocytopenic Purpura in Pediatric Patients From a Low-Income Country

This study presents a comprehensive analysis of two cases of acquired thrombotic thrombocytopenic purpura (aTTP) observed in pediatric patients from a low-income country. In the instances described, both patients underwent a treatment regimen involving plasma exchange and immunosuppressive therapy conducted without the use of caplacizumab. Caplacizumab, an approved drug for adults known for its limited availability and high cost, has exhibited efficacy in reducing response time and recurrence frequency in aTTP cases. This approach resulted in significant clinical improvement and eventual remission of symptoms in one of the cases. These cases underscore the urgent necessity for a more inclusive approach in national health programs and international treatment guidelines. Specifically, there is a call to expand the existing comprehensive treatment algorithms to accommodate countries lacking access to caplacizumab. This adaptation aims to ensure the availability of suitable and effective treatment options for aTTP patients in regions facing limited pharmaceutical accessibility.

Global Health Resource Utilization and Cost-Effectiveness of Therapeutics and Diagnostics in Immune Thrombotic Thrombocytopenic Purpura (TTP)

In this review, we examine the current landscape of health resource utilization and cost-effectiveness data in the care of patient populations with immune thrombotic thrombocytopenic purpura. We focus on the therapeutic (therapeutic plasma exchange, glucocorticoids, rituximab, caplacizumab) and diagnostic (ADAMTS13 assay) health technologies employed in the care of patients with this rare disease. Health resource utilization and cost-effectiveness data are limited to the high-income country context. Measurement of TTP-specific utility weights in the high-income country context and collection of health resource utilization data in the low- and middle-income country settings would enable an evaluation of country-specific quality-adjusted life expectancy and cost-effectiveness of these therapeutic and diagnostic health technologies. This quantification of value is one way to mitigate cost concerns where they exist.

Spanish registry of thrombotic thrombocytopenic purpura (REPTT): Data evidence and new developments

Immuno Thrombotic thrombocytopenic purpura (iTTP) is a rare and potentially fatal disorder characterized by systemic microvascular thrombosis because of a severe deficiency of ADAMTS13. It is difficult to generate knowledge about TTP because of its low incidence and the lack of clinical trials. Most of the evidence on diagnosis, treatment, and prognosis has been generated from real-world data registries. In 2004, the Spanish Apheresis Group (GEA) implemented the Spanish registry of TTP (REPTT) with 438 patients suffering 684 acute episodes in 53 hospitals up to January 2022. REPTT has studied several aspects of TTP in Spain. The iTTP incidence in Spain our country is 2.67 (95 % CI 1.90-3.45) and the prevalence is 21.44 (95 % CI % 19.10-23.73) patients per million inhabitants. The refractoriness incidence is 4.8 % and exacerbation incidence was 8.4 %, with a median of follow-up of 131.5 months (IQR: 14-178 months). In a 2018 review, the mortality in the first episode due to TTP was 7.8 %. We have also found that de novo episodes require fewer PEX procedures than relapses. Since June 2023, REPTT will involve Spain and Portugal, with a recommended sampling protocol and new variables to improve the neurological, vascular and quality of life evaluation of these patients. The main strength of this project will be the involvement of a combined population of more than 57 million inhabitants, which implies an annual incidence of close to 180 acute episodes per year. This will allow us to provide better answers to questions like treatment efficacy, associated morbidity and mortality, and the possible neurocognitive and cardiac sequelae.

Characterizing the process of urgent referrals and transfers to a large tertiary care apheresis centre in Ontario: A retrospective database review

BACKGROUND

Therapeutic plasma exchange (TPE) and red blood cell exchange (RBCX) are life-saving apheresis procedures offered in 7 Ontario hospitals. Most referrals are directed by CritiCall Ontario (CritiCall), a 24/7 service funded by the Ontario Ministry of Health and Long-Term Care. We used CritiCall data to examine referral requests, acceptances, and transfers for urgent apheresis to our centre.

METHODS

Retrospective CritiCall referral and transfer data for urgent apheresis between October 2013 and December 2018 were included. Continuous variables were analyzed by linear regression. Categorical variables were analyzed using nonparametric tests.

RESULTS

Eighty-five cases (52 TPE, 33 RBCX) were identified. Median patient age was 52 years (interquartile range [IQR] 32) for TPE, 29 years (IQR 18) for RBCX. Most patients (58%) were female. Total time from referral to arrival at our centre was 243 (IQR 166) minutes. The greatest proportion of this total was from patient acceptance to arrival (169 [IQR 112] minutes). Median distance between referring and accepting centres was 39 (IQR 30) kilometres, with ground transportation used most often. Multiple linear regression examining factors that contribute to total time demonstrated that the number of physicians contacted prior to patient acceptance and inter-hospital distance were independently associated (p = 0.007 and p = 0.048, respectively).

INTERPRETATION

Addressing modifiable factors to reduce time is important given that time to initiate treatment is associated with better outcomes. Quality improvement strategies should be aimed at coordinated provincial resource sharing, pairing referrals with nearest available apheresis centres, and creating efficiency in the interval between patient acceptance and arrival.

Lombardy diagnostic and therapeutic network of thrombotic microangiopathy

Background

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening thrombotic microangiopathy (TMA) requiring urgent treatment. Standardization of its diagnosis and optimal management is challenging. This study aimed to evaluate the role of centralized, rapid testing of ADAMTS13 in patients experiencing acute TMAs requiring plasma-exchange (PEX) and to estimate the incidence of TTP in a large Italian Region.

Methods

We perfomed a cohort study in the frame of the project “Set-up of a Lombardy network for the study and treatment of patients undergoing apheresis”, including 11 transfusion centers in the Region. Consecutive patients referred from 2014 to 2016 with acute TMAs requiring PEX were enrolled. Centralized ADAMTS13 activity testing was performed at the Milan Hemophilia and Thrombosis Center within 24 h.

Results

Forty-three TMA patients (44 events) were enrolled, of whom 35 (81%) had severe ADAMTS13 deficiency. Patients with severe ADAMTS13 deficiency were younger, mainly women, with a higher prevalence of autoimmune disorders and a lower prevalence of cancer. Clinical and laboratory characteristics of patients with and without severe ADAMTS13 deficiency largely overlapped, with a lower platelet count being the only baseline marker that significantly differed between the two patient groups (ADAMTS13 activity < 10% vs ≥ 10%: median difference of -27 × 10⁹/l, 95% CI − 37 to − 3). PEX treatment was initiated in all patients, but soon discontinued in cases without severe ADAMTS13 deficiency. In this group, the mortality rate was higher and no episode exacerbations or relapses within 6 months occured. The estimated average annual incidence of acute acquired TTP events was 1.17 [0.78–1.55] per million people.

Conclusions

Severe ADAMTS13 deficiency distinguished two groups of patients with largely overlapping clinical features but different treatment and disease course. This study provides a feasible model implemented in a large Italian region for the practical clinical approach to TMAs and underlines the importance of urgent ADAMTS13 activity testing for an accurate differential diagnosis and therapeutic approach.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02400-y.

Recent advances in the management of immune-mediated thrombotic thrombocytopenic purpura

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially life-threatening thrombotic microangiopathy caused by autoantibody-mediated severe ADAMTS13 deficiency. TTP should be suspected in patients with microangiopathic hemolytic anemia and thrombocytopenia without a definite cause. Early detection of iTTP and prompt treatment with plasma exchange and corticosteroids are essential. Rituximab administration should be considered for refractory or relapsed iTTP, and can be used as a first-line adjuvant or preemptive therapy. Treatment with caplacizumab, a novel anti-von Willebrand factor nanobody, resulted in a faster time to platelet count response, significant reduction in iTTP-related deaths, and reduced incidence of refractory iTTP. TTP survivors showed a higher rate of chronic morbidities, including cardiovascular disease and neurocognitive impairment, which can lead to a poor quality of life and higher mortality rate. Meticulous long-term follow-up of TTP survivors is crucial.

TTP: From empiricism for an enigmatic disease to targeted molecular therapies

The 100th anniversary of the first description of Thrombotic Thrombocytopenic Purpura (TTP) as a disease by Dr. Eli Moschcowitz approaches. For many decades, TTP remained mostly a mysterious fatal condition, where diagnosis was often post-mortem. Initially a pentad of symptoms was identified, a pattern that later revealed to be fallible. Sporadic observations led to empiric interventions that allowed for the first impactful breakthrough in TTP treatment, almost 70 years after its first description: the introduction of plasma exchange and infusions as treatments. The main body of knowledge within the field was gathered in the latest three decades: patient registries were set and proved crucial for advancements; the general mechanisms of disease have been described; the diagnosis was refined; new treatments and biomarkers with improvements on prognosis and management were introduced. Further changes and improvements are expected in the upcoming decades. In this review, we provide a brief historic overview of TTP, as an illustrative example of the success of translational medicine enabling to rapidly shift from a management largely based on empiricism to targeted therapies and personalized medicine, for the benefit of patients. Current management options and present and future perspectives in this still evolving field are summarized.

Severe Thrombotic Thrombocytopenic Purpura (TTP) with Organ Failure in Critically Ill Patients

Thrombotic thrombocytopenic purpura (TTP) is a multiorgan disorder. Organ dysfunction occurs as a consequence of widespread microvascular thrombosis, especially in the heart, brain and kidney, causing transient or partial occlusion of vessels, resulting in organ ischemia. Intensive care unit (ICU) admission varies between 40% and 100% of patients with TTP, either because of severe organ failure or in order to initiate emergency plasma exchange (PEx). Severe neurologic manifestations and cardiac involvement have been associated with higher mortality. Acute kidney injury, although usually less severe than that in hemolytic and uremic syndrome, is common during TTP. Initial management in the ICU should always be considered in TTP patients. The current treatment of TTP in the acute phase is based on urgent PEx, combined with corticosteroid therapy, B-cell-targeted immunotherapy, rituximab and inhibition of the interaction between ultra-large Von Willebrand factor multimers and platelets, using caplacizumab, a monoclonal antibody. ICU management permits close monitoring and the rapid introduction of life-sustaining therapies. This review details the epidemiology of TTP in the ICU, organ failures of critically ill patients with TTP, and the initial management of TTP patients in the ICU.

ADAMTS13 Autoantibodies and Burden of Care in Immune Thrombotic Thrombocytopenic purpura: New Evidence and Future Implications

The introduction Caplacizumab in the management of Immune thrombotic thrombocytopenic purpura (iTTP) has raised different questions, considering its cost-efficacy and the optimal immunosuppressive treatment (IST) to associate. A retrospective multicenter collection of 42 first iTTP cases was conducted to identify variables associated with a higher burden of care and necessity of an implemented IST with early Rituximab (RTX) rescue. A significant correlation resulted between ADAMTS13 inhibitors (ADAMTS13inh) at diagnosis with total plasma exchange (PEXtot) and PEX needed to achieve clinical response (PEXtoCR, r = 0.46; r = 0.48), along with age (r = - 0.31; r = -0.35), platelet count (r = -0.30; r = -0.30), LDH (r = 0.44; r = 0.41) and total bilirubin (r = 0.54; r = 0.35). ADAMTS13inh also correlated with number of days of hospitalization (DoH, r = 0.44). A significant difference was observed in terms of median ADAMTS13inh titer at diagnosis in patient treated with RTX rescue and those responding to only steroid treatment. Thus, ADAMTS13inh titer resulted a marker of iTTP burden of care, associated with higher number of PEXtot, PEXtoCR, DoH and higher probability of needing RTX rescue to achieve clinical response and could be a useful tool for management of new iTTP cases and an interesting variable to optimize iTTP cases stratification in future Caplacizumab cost-efficacy analysis.

Focus on Key Issues in Immune Thrombotic Thrombocytopenic Purpura: Italian Experience of Six Centers

Immune-mediated thrombotic thrombocytopenic purpura is a rare and challenging hematological disease caused by the antibody anti-ADAMTS13. Though the mortality rate has decreased considerably in recent years, fatalities still remain unacceptable. This study aimed at further adding to the existing knowledge of this medical challenge. We enrolled 89 consecutive patients observed in six Italian centers (from 8 August 2013 to 28 May 2021) with a diagnosis of immune-mediated thrombotic thrombocytopenic purpura. Clinical information and blood parameters were collected for all patients. We describe clinical manifestations and laboratory data, possible risk factors and the therapeutic management of first episodes or relapses. A total of 74 first episodes and 19 relapses (median 3 years (interquartile range (IQR): 2-7)) were recorded. Seventy percent of patients enrolled at the first episode showed neurological signs and/or symptoms. All the patients enrolled at the first episode were treated with plasma exchange (median = 12; IQR: 8-19.5) and methylprednisolone (1 mg/kg/day). Rituximab (375 mg/m² weekly for four weeks) and caplacizumab were given to 15 (20.2%) and 2 patients (2.6%), respectively. We observed an overall mortality of 5.4% in the follow-up (median 60 months; IQR: 36.0-103.5). All fatalities occurred after a diagnostic delay. Present data point to the importance of the early detection of factors mostly associated with poor outcomes. It is likely that use of caplacizumab could improve the prognosis in those patients.

Evaluation and Management of Thrombotic Thrombocytopenic Purpura in the Emergency Department

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a dangerous condition that can be misdiagnosed in the emergency department.

OBJECTIVE

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of TTP, with a focus on emergency clinicians.

DISCUSSION

TTP is a disorder with microangiopathic hemolytic anemia, severe thrombocytopenia, and multiorgan ischemic injury. It may be acquired or hereditary, and is caused by a reduced amount or function of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), which is an enzyme involved in cleaving von Willebrand factor. The classic presentation of TTP includes fever, neurologic abnormalities, thrombocytopenia with purpura, microangiopathic hemolytic anemia, and acute renal injury. However, < 7% of cases have all of these findings present. Testing should include a complete blood count, complete metabolic panel, blood smear, coagulation panel, fibrinogen, D-dimer, lactate dehydrogenase, ADAMTS13 level, troponin, human immunodeficiency virus assessment, urinalysis, pregnancy test as appropriate, and electrocardiogram. Management includes hematology consultation if available, plasma exchange and corticosteroids, and treatment of end-organ complications. All patients require admission for treatment and close monitoring.

CONCLUSION

TTP is a potentially dangerous medical condition requiring rapid diagnosis and management. It is essential for emergency clinicians to know how to diagnose and treat this disorder.

Pattern of Brain Injury in Patients With Thrombotic Thrombocytopenic Purpura in the Precaplacizumab Era

OBJECTIVES

To describe short- and long-term neurologic prognosis of patients with thrombotic thrombocytopenic purpura and to identify clusters associated with evolution.

DESIGN

Prospective French cohort.

SETTING

ICU in a reference center.

PATIENTS

All consecutive patients with newly diagnosed thrombocytopenic purpura.

INTERVENTION

Comprehensive clinical, biological, and radiological evaluation at admission. Neurocognitive recovery was assessed using Glasgow Outcome Scale (range 1-5, with 1 representing death and 5 representing no or minimal neurologic deficit).

MEASUREMENTS AND MAIN RESULTS

Among the 130 newly diagnosed patients with thrombocytopenic purpura, 108 (83%; age 43 [30-52]; 73% women) presented with neurologic signs, including headaches (51%), limb weakness, paresthesia, and/or aphasia (49%), pyramidal syndrome (30%), decreased consciousness (20%), seizure (19%), cognitive impairment (34%), cerebellar syndrome (18%), and visual symptoms (20%). A hierarchical cluster analysis identified three distinct groups of patients. Cluster 1 included younger patients (37 [27-48], 41 [32-52], and 48 [35-54], in clusters 1, 2 and 3, respectively; p = 0.045), with a predominance of headaches (75%, 27%, and 36%; p < 0.0001). Cluster 2 patients had ataxic gait and cerebellar syndrome (77%, 0%, and 0%; p < 0.0001) and dizziness (50%, 0%, and 0%; p < 0.0001). Cluster 3 included patients with delirium (36%, 0%, and 9%; p < 0.0001), obtundation (58%, 0%, and 24%; p < 0.0001), and seizure (36%, 0%, and 14%; p < 0.0001). Acute kidney injury was 32%, 68%, and 77%, in clusters 1, 2, and 3, respectively (p < 0.0001). The three clusters did not differ for other biological or brain imaging. After a median follow-up of 34 months (12-71 mo), 100 patients (93%) were alive with full neurocognitive recovery (i.e., Glasgow Outcome Scale score 5) in 89 patients (89%). Patients from cluster 1 more frequently exhibited full recovery (Glasgow Outcome Scale score of 5) compared with clusters 2 and 3, (44 [98%], 13 [65%], and 21 [60%] at 3 mo; p < 0.0001), (44 [100%], 15 [68%], and 23 [69%] at 6 mo; p < 0.0001), and (40 [100%], 15 [79%], and 20 [57%] at 1 yr; p < 0.0001).

CONCLUSIONS

Initial clinical neurologic evaluation in thrombocytopenic purpura patients distinguishes three groups of patients with different clinical and functional outcomes.

Thrombotic microangiopathies: First report of 294 cases from a single institution experience in Argentina

Introduction

Introduction: Thrombotic microangiopathies (TMAs) are rare disorders associated with fatal outcomes if left uncared for. However, healthcare problems in developing countries tend to limit medical assistance to patients.

Methods

Methods: We prospectively studied an Argentine cohort of 294 consecutive patients from 2013 to 2016. Patients’ subcategory classification relied on clinical symptoms and presence or absence of trigger events associated with TMA.

Results

Main suspected disorders were the primary TMAs known as thrombotic thrombocytopenic purpura (TTP) (n = 72/294, 24%) and atypical haemolytic uraemic syndrome (aHUS) (n = 94/294, 32%). In acute phase, demographic parameters for acquired TTP (aTTP) (n = 28) and aHUS (n = 47) showed that both groups were characterised by a young median age (37 and 25 years, respectively) and female predominance (60% and 86%). Median of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 activity was significantly lower in aTTP than in aHUS group (1.4% vs 83%) and was associated with a more severe thrombocytopenia (15 × 10⁹ vs 53 × 10⁹/L). Creatinine (Cr) and urea (Ur) were significantly increased in aHUS compared to aTTP subjects (Cr: 3.7 vs 0.7 mg/dL, Ur: 118 vs 33 mg/dL). Gastrointestinal and neurological symptoms were more frequent in aHUS and aTTP, respectively.

Conclusion

The first description of a TMA cohort in Argentina revealed similar clinical presentations to those of other countries.

Incidence, diagnosis, and outcome of immune-mediated thrombotic thrombocytopenic purpura: A nationwide survey by the Spanish registry of thrombotic thrombocytopenic purpura

BACKGROUND

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare disease characterized by the presence of anti-ADAMTS13 autoantibodies. Achieving accurate information on incidence and customary disease management is important to provide appropriate diagnostic and therapeutic resources. The aim of this study was to determine the incidence and outcomes of iTTP in Spain.

STUDY DESIGN AND METHODS

A cross-sectional survey was carried out among Spanish hospitals, focused on iTTP patients ≥16 years old attended between 2015 and 2017, and those at follow-up before that interval. Incidence, prevalence, mortality, refractoriness, exacerbations, treatment complications, relapses, and sequelae were estimated.

RESULTS

Forty-two hospitals covering roughly 20 million inhabitants answered the survey and reported 203 episodes (138 newly-diagnosed and 65 relapses), of which 193 (95.1%) were treated. Incidence was 2.67 (95% CI 1.90-3.45) patients per million inhabitants per year and prevalence 21.44 (95% CI% 19.10-23.73) patients per million inhabitants. At diagnosis, ADAMTS13 activity and anti-ADAMTS13 autoantibody were measured in 97% and 84.3% of reported episodes, respectively. Fifteen patients (7.4%) died as a direct consequence of iTTP, 6 of them before receiving any iTTP-specific treatment. Thirty-one (16.1%) of the 193 treated episodes were refractory to plasma exchange and corticosteroids, and 51 (26.4%) suffered at least one exacerbation.

CONCLUSION

iTTP incidence and prevalence were somewhat higher than those documented in neighboring countries. Together with data on treatments and outcomes, this information will allow us to better estimate what is needed to improve diagnosis and prognosis of iTTP patients in Spain.

Neurological manifestations of thrombotic microangiopathy syndromes in adult patients

The objective of this study was to compare the frequency and severity of neurologic manifestations in adult patients diagnosed with thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS) and atypical HUS (aHUS). This is a retrospective cohort study of adult patients diagnosed with TTP, HUS and atypical HUS hospitalized at a tertiary center between January 2004 and October 2016. A total of 42 TTP, 16 HUS and 20 aHUS episodes were reviewed to collect clinical, laboratory and radiographic data, as well as information regarding long-term functional outcome. Neurologic symptoms are more common in patients with TTP and HUS as compared to aHUS (p < 0.001 and p = 0.002, respectively). Encephalopathy occurred in 29 TTP (69%) and 11 HUS (68%) episodes. Focal deficits were only observed in patients with TTP (n = 8 [19%]). Seizures were most commonly seen in HUS patients (n = 8 [50%]). Posterior reversible encephalopathy syndrome (PRES) was the most common neuroimaging finding in these syndromes; ischemic infarcts and hemorrhages occurred uncommonly. There was no correlation between presence of neurologic symptoms or neuroimaging abnormalities and poor outcome. Patients with TTP and HUS appear to have a similar spectrum of neurologic manifestations, whereas neurologic involvement is less common in aHUS. PRES is the most common imaging abnormality, and may present atypically. Despite presence of neurologic symptoms or neuroimaging abnormalities, patients with thrombotic microangiopathy (TMA) tend to have favorable long-term outcomes.

Thrombotic Thrombocytopenic Purpura: Pathophysiology, Diagnosis, and Management

Thrombotic thrombocytopenic purpura (TTP) is a rare thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, severe thrombocytopenia, and ischemic end organ injury due to microvascular platelet-rich thrombi. TTP results from a severe deficiency of the specific von Willebrand factor (VWF)-cleaving protease, ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13). ADAMTS13 deficiency is most commonly acquired due to anti-ADAMTS13 autoantibodies. It can also be inherited in the congenital form as a result of biallelic mutations in the ADAMTS13 gene. In adults, the condition is most often immune-mediated (iTTP) whereas congenital TTP (cTTP) is often detected in childhood or during pregnancy. iTTP occurs more often in women and is potentially lethal without prompt recognition and treatment. Front-line therapy includes daily plasma exchange with fresh frozen plasma replacement and immunosuppression with corticosteroids. Immunosuppression targeting ADAMTS13 autoantibodies with the humanized anti-CD20 monoclonal antibody rituximab is frequently added to the initial therapy. If available, anti-VWF therapy with caplacizumab is also added to the front-line setting. While it is hypothesized that refractory TTP will be less common in the era of caplacizumab, in relapsed or refractory cases cyclosporine A, N-acetylcysteine, bortezomib, cyclophosphamide, vincristine, or splenectomy can be considered. Novel agents, such as recombinant ADAMTS13, are also currently under investigation and show promise for the treatment of TTP. Long-term follow-up after the acute episode is critical to monitor for relapse and to diagnose and manage chronic sequelae of this disease.

[Diagnosis of thrombotic thrombocytopenic purpura]

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disease, disease, characterised by microangiopathic hemolytic anaemia, consumption thrombocytopenia, and organ dysfunction. The pathogenesis of TTP is attributed to the deficiency in the activity of the metalloproteinase ADAMTS13, specific von Willebrand factor cleaving protease. TTP is suspected when detecting microangiopathic hemolytic anemia, thrombocytopenia, damage to various organs. Diagnosis of TTP is confirmed by the detection of ADAMTS13 activity in plasma less than 10%. Plasma samples for the study of ADAMTS13 activity should be taken before the start of plasma transfusions or plasma exchange. In patients with severe ADAMTS-13 deficiency autoantibodies anti-ADAMTS13 and inhibitor ADAMTS13 should be investigated. Anti-ADAMTS13 antibodies belonging to IgG not always have inhibitory effects. The inhibitory effect of anti-ADAMTS13 antibodies is confirmed by mixing test. All patients with the first established diagnosis of TTP should be examined for mutations of the ADAMTS13 gene.

Reduced sensitivity of PLASMIC and French scores for the diagnosis of thrombotic thrombocytopenic purpura in older individuals

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder characterized by thrombocytopenia, microangiopathic hemolysis, and ischemic organ failure. The PLASMIC and French TTP scores can help guide clinical decisions when ADAMTS13 testing is not immediately available. Older individuals often present atypically, but the impact of age on these tools is not known.

STUDY DESIGN AND METHODS

We calculated the sensitivity and specificity of the PLASMIC and French TTP scores in patients enrolled in the Johns Hopkins thrombotic microangiopathy (TMA) registry.

RESULTS

Of 257 patients with TMA enrolled in the registry, we excluded patients less than 18 years of age (n = 19), with prior TMA (n = 81) or who initially presented at another hospital (n = 25). The remaining 132 patients (75 with TTP and 57 with other TMA) were analyzed. Sensitivity of a French score of 2 decreased with age and was 72.2%, 61.5%, and 46.2% for ages 18 to 39, 40 to 59, and ≥ 60 years old, respectively. A PLASMIC score ≥ 5 had higher sensitivity than the French score but this also decreased with age; sensitivity was 91.4% (95% confidence interval [CI], 76.9-98.2), 78.3% (95% CI, 56.3-92.5), and 76.9% (95% CI, 46.2-95.0) for patients 18 to 39, 40 to 59, and ≥ 60 years old, respectively. Older patients had higher platelet counts and serum creatinine than the youngest group, contributing to the loss in sensitivity.

CONCLUSION

The PLASMIC and French TTP scores have reduced sensitivity at age ≥ 60 years and are less reliable in identifying TTP in older patients. A high index of suspicion and availability of rapid ADAMTS13 assays is required to correctly diagnose all patients with TTP.

Baseline characteristics of patients with atypical haemolytic uraemic syndrome (aHUS): The Australian cohort in a global aHUS registry

AIMS

To describe the baseline characteristics and treatment of Australian patients diagnosed with atypical haemolytic uraemic syndrome (aHUS) reported to the Global aHUS Registry.

METHODS

Descriptive analysis of the Australian cohort with aHUS (n = 106) was undertaken for demographics, disease characteristics and prior treatment with eculizumab; comparing with the global cohort (n = 1688) for certain pre-specified disease characteristics.

RESULTS

In Australia, almost two-thirds of patients diagnosed with aHUS were female and over 80% of patients were Caucasians, with similar proportions reported in the global cohort. Less than 6% of patients in the Australia and global cohorts were reported to have a history of autoimmune disease (4% vs 2%, respectively; P = .21) or cancer (5% vs 5%, respectively; P = .93), conditions that have been associated with secondary HUS. In the Australian cohort, 26% had received a kidney transplant and 68% of patients had received eculizumab. Kidneys were the most common organ involvement, followed by gastrointestinal tract (26%) and cardiovascular system (19%), with 35% of patients reported to have had at least two organs involved within 6 months prior to baseline visit or entry into the registry. Complement factor H was the most common pathogenic complement gene variant in the Australian patients.

CONCLUSION

Data from the aHUS registry confirms and defines region-specific disease characteristics among a selected group of Australian children and adults with aHUS reported to the registry. Ongoing and more inclusive data will provide further information about temporal trends and treatment outcomes, representing a unique opportunity for clinicians and researchers to further develop knowledge surrounding this rare disease.

Thrombotic thrombocytopenic purpura associated with pesticides: A report of 4 cases and literature review

Thrombotic thrombocytopenic purpura (TTP) is a disease characterized by the presence of microangiopathic hemolytic anemia (MAHA) and thrombocytopenia, caused by the congenital or acquired decrease of the enzyme activity which degrades unusual large vWF multimers. There is no identifiable cause in half of the acquired TTP cases. Herein, we report four possible pesticide-related cases with decreased ADAMTS13 enzyme activity, increased titer of ADAMTS13 inhibitor and typical clinical and laboratory presentation.

Thrombotic Thrombocytopenic Purpura, Heparin-Induced Thrombocytopenia, and Disseminated Intravascular Coagulation

Hemostatic abnormalities are common among critically ill patients and are associated with a high risk of bleeding. The abnormalities range from isolated thrombocytopenia or prolongation of global coagulation assays to complex disease states, such as thrombotic microangiopathic syndromes, and can be associated with a wide range of conditions, including trauma, surgery, acute disease processes, cardiopulmonary bypass, and exposure to drugs and blood products. Prompt identification of underlying causes is important because treatment strategies vary. Moreover, prompt initiation of both supportive and specific treatments is vital to decrease the morbidity and mortality in the intensive care unit.

Thrombotic thrombocytopenic purpura: A 5-year tertiary care centre experience

INTRODUCTION

Thrombotic thrombocytopenic purpura (TTP) is associated with high mortality if not managed timeously with therapeutic plasma exchange (TPE). TTP secondary to human immunodeficiency virus (HIV) infection is unique to sub-Saharan Africa. The management and outcome of TTP in the era of improved access to therapy has not been described.

METHODS

The present study describes the clinical presentation, treatment, therapeutic endpoints, and outcome of TTP patients at the Charlotte Maxeke Johannesburg Academic Hospital, South Africa. The inpatient and outpatient records of 41 consecutive adults with TTP were reviewed between 2012 and 2016. Patients were classified according to aetiology and treatment response.

RESULTS

TTP was the initial presenting feature of HIV infection in 78.0%, and 12.5% were noncompliant with antiretroviral therapy (ART). Most study patients were of black ethnicity (95%) and female gender (78.1%). Treatment included initial TPE (87.8%), plasma infusion (78.1%), antiretroviral therapy (78.3%), corticosteroids (61.0%) intensive care admission (41.5%), renal dialysis (12.2%), and other immunosuppressive agents (4.9%). The median (range) number of TPEs was 10.0 (7.0-15.0). A high rate of refractory disease (63.4%) was reported. Haemoglobin, platelet count, lactate dehydrogenase, red cell distribution width, and creatinine were reliable therapeutic end-points (P < .05). The relapse rate was 9.8% and the mortality rate was 29.3%.

CONCLUSION

The high mortality rate emphasises the importance of early diagnosis, referral, and appropriate management of TTP. Anti-retroviral therapy and adherence monitoring are essential to TTP management associated with HIV. Future studies to identify patients at risk for refractory disease are indicated.

Clinical and laboratory diagnosis of TTP: an integrated approach

Thrombotic thrombocytopenia purpura (TTP) is a rare, life-threatening disease with an incidence of approximately 2 persons per million per year. It is characterized by severe deficiency of the von Willebrand cleaving protease, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), leading to formation of platelet-rich thrombi in the microvasculature. Prompt initiation of appropriate therapy, particularly plasma exchange, may be life-saving. Diagnosis of TTP is challenging because of its diverse clinical manifestations, overlap in clinical presentation with other thrombotic microangiopathies, and limited availability of ADAMTS13 testing. Clinical prediction scores have been developed to estimate the pretest probability of severe ADAMTS13 deficiency and may be used as an adjunct to clinical judgment to guide initial management decisions. An ADAMTS13 activity level of less than 10% supports the diagnosis of TTP in appropriate clinical contexts, but many centers do not offer testing in-house and must send out the test to a reference laboratory with a turnaround time of several days. In such instances, initial management decisions must be made without the benefit of laboratory testing. In patients with TTP, inhibitor tests may be useful for distinguishing immune-mediated from congenital TTP. In this article, we review the epidemiology, natural history, and clinical presentation of TTP and laboratory assays for TTP including ADAMTS13 activity and inhibitor assays. We also describe an evidence-based approach to the evaluation of a patient with suspected TTP that integrates clinical and laboratory assessment.

A multicenter experience of thrombotic microangiopathies in Turkey: The Turkish Hematology Research and Education Group (ThREG)-TMA01 study

Thrombotic microangiopathies (TMAs) are rare, but life-threatening disorders characterized by microangiopathic hemolytic anemia and thrombocytopenia (MAHAT) associated with multiorgan dysfunction as a result of microvascular thrombosis and tissue ischemia. The differentiation of the etiology is of utmost importance as the pathophysiological basis will dictate the choice of appropriate treatment. We retrospectively evaluated 154 (99 females and 55 males) patients who received therapeutic plasma exchange (TPE) due to a presumptive diagnosis of TMA, who had serum ADAMTS13 activity/anti-ADAMTS13 antibody analysis at the time of hospital admission. The median age of the study cohort was 36 (14-84). 67 (43.5%), 32 (20.8%), 27 (17.5%) and 28 (18.2%) patients were diagnosed as thrombotic thrombocytopenic purpura (TTP), infection/complement-associated hemolytic uremic syndrome (IA/CA-HUS), secondary TMA and TMA-not otherwise specified (TMA-NOS), respectively. Patients received a median of 18 (1-75) plasma volume exchanges for 14 (153) days. 81 (52.6%) patients received concomitant steroid therapy with TPE. Treatment responses could be evaluated in 137 patients. 90 patients (65.7%) achieved clinical remission following TPE, while 47 (34.3%) patients had non-responsive disease. 25 (18.2%) non-responsive patients died during follow-up. Our study present real-life data on the distribution and follow-up of patients with TMAs who were referred to therapeutic apheresis centers for the application of TPE.

Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, severe thrombocytopenia, and organ ischemia linked to disseminated microvascular platelet rich-thrombi. TTP is specifically related to a severe deficiency in ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13), the specific von Willebrand factor-cleaving protease. ADAMTS13 deficiency is most frequently acquired via ADAMTS13 autoantibodies, but rarely, it is inherited via mutations of the ADAMTS13 gene. The first acute episode of TTP usually occurs during adulthood, with a predominant anti-ADAMTS13 autoimmune etiology. In rare cases, however, TTP begins as soon as childhood, with frequent inherited forms. TTP is ∼2-fold more frequent in women, and its outcome is characterized by a relapsing tendency. Rapid recognition of TTP is crucial to initiate appropriate treatment. The first-line therapy for acute TTP is based on daily therapeutic plasma exchange supplying deficient ADAMTS13, with or without steroids. Additional immune modulators targeting ADAMTS13 autoantibodies are mainly based on steroids and the humanized anti-CD20 monoclonal antibody rituximab. In refractory or unresponsive TTP, more intensive therapies including twice-daily plasma exchange; pulses of cyclophosphamide, vincristine, or cyclosporine A; or salvage splenectomy are considered. New drugs including N-acetylcysteine, bortezomib, recombinant ADAMTS13, and caplacizumab show promise in the management of TTP. Also, long-term follow-up of patients with TTP is crucial to identify the occurrence of other autoimmune diseases, to control relapses, and to evaluate psychophysical sequelae. Further development of both patients’ registries worldwide and innovative drugs is still needed to improve TTP management.

Profiling clinical platelet and plasma use to inform blood supply and contingency planning: PUPPY, the prospective utilization of platelets and plasma study

BACKGROUND

Demand for platelet (PLT) and plasma transfusions is increasing. Improved clinical supply and contingency planning requires greater understanding of usage profiles and urgency of clinical requirement.

STUDY DESIGN AND METHODS

This study was a random-sample survey of PLT and plasma units produced in Victoria, Australia, to determine product disposition, recipient demographics, clinical indications for transfusion, and urgency (or "deferability") of need. PLTs and fresh-frozen plasma (FFP) were tagged with a case report form before distribution.

RESULTS

A total of 1252 PLT and 1837 FFP units were tagged, comprising 8.3 and 13.3% of all products issued during the study period. The fate of 1243 PLT and 1808 FFP units was determined. Of products issued, 72.2% of PLTs and 87.8% of FFP were transfused. Hematologic and oncologic disorders accounted for 63.9% of PLT transfusions, with acute myeloid leukemia alone accounting for 26%. Conversely, surgical patients received the largest proportion of FFP (40.4%), predominantly for cardiothoracic, solid organ transplant, and vascular surgery. Approximately 15% of PLT transfusions and 35% of plasma transfusions were required within 1 hour, and 80% of PLT transfusions and 90% of FFP transfusions were required within 24 hours. Wastage rates were higher in regional blood banks.

CONCLUSION

The PUPPY study is a comprehensive and detailed population-based assessment of PLT and plasma usage, including urgency of use. It identifies specific clinical areas with high demand for PLT and FFP transfusion and demonstrates the high urgency of need for both products. These data inform clinical supply and contingency planning activities.