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

Outcomes in patients with thrombotic microangiopathy associated with a trigger following plasma exchange: A systematic literature review

Plasma exchange (PE) outcomes in patients with trigger-associated thrombotic microangiopathy (TMA) have not been comprehensively reviewed. Embase and MEDLINE® were searched on 03/14/2022 for English language articles published after 2007, alongside a congress materials search (2019-2022; PROSPERO: CRD42022325170). Studies with patients with trigger-associated TMA (excluding thrombotic thrombocytopenic purpura, 'typical' hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli, post-partum TMA, and TMAs with known genetic cause) who received PE or plasma infusion (PI) and reported treatment response (including measures), safety, patient-/caregiver-reported outcomes, or economic burden data were examined. The NICE quality appraisal checklist assessed bias risk. After screening 695 articles, 49 PE or PI studies were identified, of which 42 reported PE exclusively; most were retrospective observational studies (n = 37). The most common TMA trigger was transplantation (n = 12). The median number of PE sessions was 3.5-25.0. Outcomes following PE varied by trigger type. Treatment response rates and definitions varied (0-100 %; 24 studies); in studies of > 25 patients, response rates were 5-63 %. TMA relapse rates were 0-67 % (7 studies). Mortality was 10-91 % (23 studies). Progression to chronic kidney disease (CKD; 5 studies) and end-stage renal disease (ESRD; 6 studies) occurred in 0-93 % and 17-100 % of patients, respectively. Two serious adverse events were identified (transfusion-related injury, acute lung injury; 10 studies; 231 patients). Patients with trigger-associated TMA may experience a substantial burden in terms of mortality, relapse, and progression to CKD and ESRD following PE, leading to increased healthcare resource utilization. Additional interventions may be required.

A Systematic Review of the Epidemiology and Disease Burden of Congenital and Immune-Mediated Thrombotic Thrombocytopenic Purpura

Congenital (cTTP) and immune-mediated (iTTP) thrombotic thrombocytopenic purpura are serious and rare clotting disorders resulting from a deficiency in the ADAMTS13 enzyme. A systematic review was conducted using the Ovid® MEDLINE & Embase databases to synthesize the epidemiology and burden of cTTP and iTTP worldwide (from January 1, 2010, to February 6, 2020, with an update that covered the period January 1, 2020-February 11, 2022). Outcomes of interest were incidence and prevalence of TTP, incidence of acute episodes, mortality, burden of illness (eg complications, healthcare utilization, patient-reported outcomes) and disease management. A total of 221 eligible observational studies were included. The incidence rate of acute episodes ranged from 0.19-0.35 person-years in adult patients with cTTP, and 1.81-3.93 per million persons per year for iTTP in the general population. Triggers of acute episodes were similar for cTTP and iTTP, with pregnancy and infection the most commonly observed. Exacerbation in patients with iTTP varied widely, ranging from 2.4-63.1%. All-cause mortality was observed in 0-13.4% of patients with cTTP, across studies and follow-up periods, and in 1.1% (median follow-up: 0.4 years) to 18.8% (1 year) of patients with iTTP during acute episodes. Cardiovascular, renal, and neurological disease were common complications. TTP also led to work disturbances, feelings of anxiety and depression, and general activity impairment. TTP treatment regimens used were generally reflective of current treatment guidelines. The evidence identified describes a high patient burden, highlighting the need for effective treatment regimens leading to improvements in outcomes. Considerable evidence gaps exist, particularly for disease epidemiology, patient-reported outcomes, costs of disease management, and associated healthcare resource utilization. This review may help increase disease awareness and highlights the need for additional real-world studies, particularly in geographical regions outside the United States and Western Europe.

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.

Prospective registry of adult patients receiving therapeutic plasma exchange with a presumptive diagnosis of thrombotic microangiopathy (TMA): The Turkish hematology research and education group (ThREG)-TMA02 study

Thrombotic microanjiopathy (TMA) is a pathological diagnosis characterized by abnormalities of small vessels leading to microvascular thrombosis of arterioles and capillaries. The current prospective, non-interventional, multicenter study aimed to define the distribution of different TMA forms in adult Turkish patients who were referred for therapeutic plasma exchange (TPE) for presumptive diagnosis of TMA. Patients with serum ADAMTS13 activity <5% were diagnosed as having acquired thrombotic thrombocytopenic purpura (aTTP). Patients presenting with ADAMTS13 activity 6-10 % / normal renal function and patients with ADAMTS13 activity >10 %, normal renal function and no secondary TMA were treated as unclassified TMA. The study included a total of 80 patients (women: 50; man: 30) with a median age of 48 (20-74). Detailed evaluation at 1 month after hospital admission revealed aTTP, secondary TMA, infection/complement-associated hemolytic uremic syndrome and unclassified TMA in 29 (36.2 %), 22 (27.5 %), 23 (28.8 %) and 6 (7.5 %) patients respectively. As subclassification of various TMAs will dictate specific therapy, proper diagnosis in a timely manner is of utmost clinical significance.

Prospective registry of adult patients receiving therapeutic plasma exchange with a presumptive diagnosis of thrombotic microangiopathy (TMA): The Turkish hematology research and education group (ThREG)-TMA02 study

Thrombotic microangiopathy(TMA) is a pathological diagnosis characterized by abnormalities of small vessels leading to microvascular thrombosis of arterioles and capillaries. The current prospective, non-interventional, multicenter (n:18) study aimed to define distribution of different TMA forms in adult Turkish patients who were referred for therapeutic plasma exchange (TPE) for a presumptive diagnosis of TMA. Patients with serum ADAMTS13 activity <5% were diagnosed as acquired thrombotic thrombocytopenic purpura (aTTP). Patients presenting with ADAMTS13 activity 6-10 % / normal renal function and patients with ADAMTS13 activity >10 %, normal renal function and no secondary TMA were treated as unclassified TMA. The study included a total of 97 patients (female: 60; male: 30) with a median age of 48 (18-74). Detailed evaluation at 1 month after hospital admission revealed aTTP, secondary TMA, infection/complement-associated hemolytic uremic syndrome and unclassified TMA in 32 (33 %), 33 (34 %), 26 (27 %) and 6 (6%) patients respectively. As subclassification of various TMAs will dictate specific therapy, proper diagnosis in a timely manner is of utmost clinical significance.

Comparison of Clinical Scoring Systems in the Management of Patients with Microangiopathic Hemolytic Anemia and Thrombocytopenia

Objective:

Several clinical scoring systems have been developed for the differential diagnosis of thrombotic microangiopathies (TMAs), all to predict and identify patients with ADAMTS13 deficiency and to start treatment as soon as possible. The first scoring system in this regard was the Bentley score, and the French score and PLASMIC score were developed afterwards.

Materials and Methods:

We aimed to evaluate the laboratory parameters and clinical features of patients who underwent plasma exchange with a prediagnosis of TTP at our clinic between 2007 and 2019 and whose ADAMTS13 enzyme levels were measured and to compare the findings with the scoring systems.

Results:

Data of 35 patients were evaluated. Twelve patients were evaluated as high risk according to all three scoring systems. A statistically significant relation was observed between all three scoring systems and ADAMTS13 levels.

Conclusion:

A moderate correlation was found between all three scoring systems and ADAMTS13 levels. We observed similar potential strength of all three scoring systems to predict TTP among other TMAs and we conclude that they are applicable in daily practice.