Diagnostic uncertainty presented barriers to the timely management of acute thrombotic thrombocytopenic purpura in the United Kingdom between 2014 and 2019

De-novo immune-mediated thrombotic thrombocytopenic purpura following surgical and non-surgical procedures: A systematic review

When de-novo immune-mediated thrombotic thrombocytopenic purpura (TTP) is diagnosed following an invasive procedure, clinical presentation patterns and outcomes are poorly defined. Therefore, in a systematic literature review of patients diagnosed with TTP following an invasive surgical or non-surgical procedure, we identified 19 studies reporting data on 25 patients. These data suggest that 1) TTP pathogenesis likely begins prior to the invasive procedure, 2) patients experience significant diagnostic delays, and 3) there is a high incidence of renal replacement therapy. Although invasive procedures may trigger TTP, further studies are needed to clarify the mechanisms underlying this association.

Should we consider caplacizumab as routine treatment for acute thrombotic thrombocytopenic purpura? An expert perspective on the pros and cons

INTRODUCTION

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening disorder. Caplacizumab has been the latest drug incorporated into the initial treatment of acute episodes, allowing for faster platelet recovery and a decrease in refractoriness, exacerbation, thromboembolic events, and mortality. However, caplacizumab is also associated with a bleeding risk and higher treatment costs, which prevent many centers from using it universally.

AREAS COVERED

Studies that included iTTP and/or caplacizumab to date were selected for this review using PubMed and MEDLINE platforms. We describe outcomes in the pre-caplacizumab era and after it, highlighting the benefits and risks of its use early in frontline, and also pointing out special situations that require careful management.

EXPERT OPINION

It is clear that the availability of caplacizumab has significantly and favorably impacted the management of iTTP patients. Whether this improvement is cost-effective still remains uncertain, and data on long-term sequelae and different healthcare systems will help to clarify this point. In addition, evidence of the bleeding/thrombotic risk of iTTP patients under this drug needs to be better addressed in future studies.

Misdiagnosis of thrombotic microangiopathy in the emergency department: a multicenter retrospective study

To estimate the rate of inappropriate diagnosis in patients who visited the ED with thrombotic microangiopathy (TMA) and to assess the factors and outcomes associated with emergency department (ED) misdiagnosis. Retrospective multicenter study of adult patients admitted to the intensive care unit (ICU) for TMA from 2012 to 2021 who had previously attended the ED for a reason related to TMA. Patient characteristics and outcomes were compared in a univariate analysis based on whether a TMA diagnosis was mentioned in the ED or not. Forty patients were included. The diagnosis of TMA was not mentioned in the ED in 16 patients (40%). Patients for whom the diagnosis was mentioned in the ED had more frequently a request for schistocytes research, and therefore had more often objectified schistocytes. They also had more frequently a troponin dosage in the ED (even if the difference was not significant), an ECG performed or interpreted, and were admitted more quickly in the ICU (0 [0-0] vs 2 [0-2] days; P = 0.002). Hemoglobin levels decreased significantly in both groups, and creatinine levels increased significantly in the misdiagnosis group between ED arrival and ICU admission. In patients with a final diagnosis of TTP, the time to platelets durable recovery was shorter for those in whom the diagnosis was mentioned in the ED without reaching statistical significance (7 [5-11] vs 14 [5-21] days; P = 0.3).

Evaluation of two fully automated ADAMTS13 activity assays in comparison to manual FRET assay

INTRODUCTION

The objective of the present study was to evaluate and compare the validity and utility of two fully automated ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity assays for clinical diagnostic decision-making and to compare their performance.

METHODS

Two automated ADAMTS13 activity assays (Werfen HemosIL® AcuStar ADAMTS13 Activity, Technoclone Technofluor ADAMTS13 Activity) were compared with a manual FRET assay (BioMedica ACTIFLUOR ADAMTS13 Activity). The following samples were used: 13 acute phase TTP (thrombotic thrombocytopenic purpura) samples from 11 different patients, one sample from a patient with congenital ADAMTS13 deficiency, 16 samples from control patients, three follow-up samples from TTP patients in long-term remission and one sample from a patient with stem cell transplantation related thrombotic microangiopathy (TMA). The WHO 1st International Standard for ADAMTS13 and several dilutions of normal plasma with ADAMTS13-depleted normal plasma were also tested. Statistical analysis included descriptive statistics, sensitivity and specificity, Passing & Bablok regression and Bland-Altman plot.

RESULTS

The quantitative comparison between the HemosIL® (x) and Technofluor (y) methods showed a strong correlation (Pearson r = 0.98, n = 49). When considering an ADAMTS13 activity of <10% as a hallmark for the diagnosis of TTP, two fully automated assays were both able to identify all TTP- and non-TTP-samples correctly, resulting in sensitivities and specificities of 100%.

CONCLUSION

Both fully automated ADAMTS13 activity assays showed a good diagnostic performance and quantitative correlation among themselves, discriminating reliably between TTP- and non-TTP-patients.

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.

Acute Hepatitis E Induced the First Episode of Immune-Mediated Thrombotic Thrombocytopenic Purpura: The First Case Report

Purpose

Hepatitis E virus infection mainly presents with liver-related symptoms, and multiple studies have shown that hepatitis E virus infection can also induce extrahepatic-related symptoms. Thrombotic thrombocytopenic purpura is an uncommon and fatal thrombotic microangiopathy characterized by severe thrombocytopenia, organ damage, and microangiopathic haemolytic anaemia. We report the first case in which acute hepatitis E induced the first episode of immune-mediated thrombotic thrombocytopenic purpura.

Patients and Methods

A 53-year-old male was admitted to our emergency department with fever, thrombocytopenia, and abnormal liver function. Laboratory tests revealed significant bilirubin, AST, and ALT elevations, renal impairment, positive anti-HEV IgM and IgG antibody results, schistocytes on the blood smear, 0% ADAMTS-13 activity, and positive ADAMTS13 inhibitor results. He was diagnosed with acute hepatitis E, which induced the first episode of immune-mediated thrombotic thrombocytopenic purpura.

Results

After receiving treatment with plasmapheresis, glucocorticoid medication, rituximab, and other supportive medicines, the patient's physiological circumstances and laboratory indicators improved, and a 4-month follow-up revealed no abnormalities.

Conclusion

This is a unique case report of an acute hepatitis E-induced immune-mediated thrombotic thrombocytopenic purpura initial episode. This case report offers evidence that hepatitis E virus infection can cause thrombotic thrombocytopenic purpura. In patients with abnormal liver function and thrombocytopenia, we advise screening for hepatitis E or thrombotic thrombocytopenic purpura.

Challenges in the diagnosis of thrombotic thrombocytopenic purpura

INTRODUCTION

Immune-mediated TTP (iTTP) is a rare condition without pathognomonic signs and symptoms. For this reason, the diagnosis of iTTP may be delayed or even missed, with potentially catastrophic consequences.

AREAS COVERED

The authors performed an extensive literature review on the diagnosis of iTTP and its challenges combined with their own experience in a referral center for patients with iTTP.

EXPERT OPINION

Although a definitive diagnosis of iTTP depends on the ADAMTS13 activity result, timely testing is rarely available at many centers to which patients present. If less complex tests were to become available, they would decrease the chances of late and/or missed diagnoses of iTTP throughout the world. While clinical scores to estimate the likelihood of iTTP exist, they are not well known, and can be misleading if used in the wrong context. Furthermore, the three scoring systems (PLASMIC, Bentley, and French) only moderately correlate with each other, which further complicates the landscape. The existence of these scores and how they should be used in practice is but one opportunity that can be seized through more robust programs to educate nonspecialist clinicians on how to recognize and treat patients with iTTP.

In patients with suspected immune TTP, admission source impacts hospital length of stay and time to therapeutic plasma exchange impacts clinical outcomes

INTRODUCTION

When immune thrombotic thrombocytopenic purpura (TTP) is suspected, outcomes are impacted by time to therapeutic plasma exchange (TPE). We evaluated the impact of time to TPE on outcomes in suspected TTP cases admitted through the Emergency Department (ED) vs. transferred from another facility (Transfer).

MATERIALS AND METHODS

In a retrospective analysis of the National Inpatient Sample, we examined the association between TTP outcomes and admission source (ED vs. Transfer) for the primary outcome of time to TPE. A second stratified analyses within each analytic group examined the association of time to TPE (<1 day, 1 day, 2 days, and >2 days) and outcomes for the composite outcome of mortality, major bleeding and thrombosis.

RESULTS

Of 1195 cases, 793 (66 %) were admitted through the ED and 402 (34 %) were transferred. Compared to ED cases, Transfers had a longer hospital length of stay (14.69 vs. 16.65 days, p = 0.0060). For ED cases, TPE after >2 days was associated with higher odds of the composite outcome (OR = 1.68 95 % CI: 1.11-2.54; p = 0.0150) and mortality (OR = 3.01 95 % CI: 1.38-6.57; p = 0.0056). For Transfers, TPE on day 2 was associated with higher odds of the composite outcome (OR = 3.00 95 % CI: 1.31-6.89; p = 0.0096) and mortality (OR = 4.95 95 % CI: 1.12-21.88; p = 0.0350).

CONCLUSIONS

In suspected TTP admitted through the ED or transferred, there was no significant difference in time to TPE. A longer time to TPE was associated with worse outcomes. Future studies should evaluate strategies to decrease initial time to TPE.