Improved survival with plasma exchange in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome

Complement Inhibitors in the Management of Complement-Mediated Hemolytic Uremic Syndrome and Paroxysmal Nocturnal Hemoglobinuria

BACKGROUND

Complement-mediated HUS (CM-HUS) and paroxysmal nocturnal hemoglobinuria (PNH) are rare hematologic disorders that cause dysregulation and hyperactivation of the complement system. Historically, treatment of CM-HUS involved plasma exchange (PLEX), often with limited benefit and variable tolerance. Conversely, PNH was treated with supportive care or hemopoietic stem cell transplant. Within the last decade, monoclonal antibody therapies that block terminal complement pathway activation, have emerged as less invasive and more efficacious options for management of both disorders. This manuscript seeks to discuss a relevant clinical case of CM-HUS and the evolving landscape of complement inhibitor therapies for CM-HUS and PNH.

AREAS OF UNCERTAINTY

Eculizumab, the first humanized anti-C5 monoclonal antibody, has been the standard of care in treating CM-HUS and PNH for over a decade. Although eculizumab has remained an effective agent, the variability in ease and frequency of administration has remained an obstacle for patients. The development of novel complement inhibitor therapies with longer half-lives, has allowed for changes in frequency and route of administration, thus improving patient QOL. However, there are limited prospective clinical trial data given disease rarity, and limited information on variable infusion frequency and length of treatment.

THERAPEUTIC ADVANCES

Recently, there has been a push to formulate complement inhibitors that improve QOL while maintaining efficacy. Ravulizumab, a derivative of eculizumab, was developed to allow for less frequent administration, while remaining efficacious. In addition, the novel oral and subcutaneous therapies, danicopan and crovalimab, respectively, along with pegcetacoplan are currently undergoing active clinical trials, and poised to further reduce treatment burden.

CONCLUSION

Complement inhibitor therapies have changed the treatment landscape for CM-HUS and PNH. With a significant emphasis on patient QOL, novel therapies continue to emerge and require an in-depth review of their appropriate use and efficacy in these rare disorders.

CLINICAL CASE

A 47-year-old woman with hypertension and hyperlipidemia presented with shortness of breath and was found to have hypertensive emergency in the setting of acute renal failure. Her serum creatinine was 13.9 mg/dL; elevated from 1.43 mg/dL 2 years before. The differential diagnosis for her acute kidney injury (AKI) included infectious, autoimmune, and hematologic processes. Infectious work-up was negative. ADAMTS13 activity level was not low at 72.9%, ruling out thrombotic thrombocytopenic purpura (TTP). Patient underwent a renal biopsy, which revealed acute on chronic thrombotic microangiopathy (TMA). A trial of eculizumab was initiated with concurrent hemodialysis. The diagnosis of CM-HUS was later confirmed by a heterozygous mutation in complement factor I (CFI), resulting in increased membrane attack complex (MAC) cascade activation. The patient was maintained on biweekly eculizumab and was eventually transitioned to ravulizumab infusions as an outpatient. Her renal failure did not recover, and the patient remains on hemodialysis while awaiting kidney transplantation.

Evaluation of thrombotic thrombocytopenic purpura and other thrombotic microangiopathies: Lessons learned from a 14-year retrospective study

INTRODUCTION

Thrombotic thrombocytopenic purpura (TTP) is a clinical thrombotic microangiopathy (TMA) syndrome defined by the pentad of symptoms. Therapeutic plasma exchange with plasma replacement is an ASFA Category I modality that can reduce morbidity and mortality if initiated early. We describe a 14-year review of patients referred for plasma exchange with a suspected diagnosis of TTP.

METHODS

For 70 patients referred for urgent plasma exchange, clinical, therapeutic, and laboratory data were retrospectively analyzed, and the diagnosis was determined.

RESULTS

Fifteen of the patients were diagnosed with TTP based upon ADAMTS-13 activity with the other 51 patients having other non-TTP TMA diagnoses. The mortality rate was significant for both TTP and non-TTP TMAs. PLASMIC scores were also calculated retrospectively and were noted to have limited value. TMA is a diagnostic challenge and encompasses different syndromes with similar presentations.

CONCLUSION

Determining an accurate diagnosis, including prompt ADAMTS-13 testing, makes it possible to initiate appropriate therapy for the multiple different TMAs that can be seen in clinical practice.

ADAMTS13 conformations and mechanism of inhibition in immune thrombotic thrombocytopenic purpura

ADAMTS13, a plasma metalloprotease that cleaves von Willebrand factor, is crucial for normal hemostasis. Acquired autoantibody-mediated deficiency of plasma ADAMTS13 results in a potentially fatal blood disorder, immune thrombotic thrombocytopenic purpura (iTTP). Plasma ADAMTS13 protease appears to exist in multiple conformations. Under physiological conditions, plasma ADAMTS13 exists predominantly in its "closed" conformation (or latent form), which may be activated by lowering pH, ligand binding, and binding of an antibody against the distal domains of ADAMTS13. In patients with iTTP, polyclonal antibodies target at various domains of ADAMTS13. However, nearly all inhibitory antibodies bind the spacer domain, whereas antibodies that bind the distal C-terminal domains may activate ADAMTS13 through removing its allosteric inhibition. Additionally, the anti-C-terminal antibodies may alter the potency of inhibitory antibodies towards ADAMTS13 activity. This review summarizes some of the most recent knowledge about the ADAMTS13 conformation and its mechanism of inhibition by its autoantibodies.

Management of acquired, immune thrombocytopenic purpura (iTTP): beyond the acute phase

Modern therapy for acute TTP has resulted in a dramatic improvement in outcomes, with the combination of plasma exchange, immunosuppression, and caplacizumab being associated with >90% survival rates following an acute episode. TTP is no longer associated with just the acute episode, but requires long-term follow-up. There remains significant morbidity associated with acute TTP, and many patients suffer marked neuropsychological sequelae, including impairment in cognitive functioning, affective disorders, and reduction in health-related quality of life measures. The focus of management beyond the acute phase centres on relapse prevention, via careful monitoring of patients and the use of either ad hoc or regular immunosuppressive therapies. The main therapy used is rituximab, but despite more limited evidence, other immunosuppressive therapies may be required to aim for normalisation of ADAMTS 13 activity. Follow-up with a reduction in ADAMTS 13 activity levels (ADAMTS 13 relapse), rituximab is central to normalisation of activity levels and prevention of a clinical relapse. Fundamental to elective therapy is the role of ADAMTS 13 activity monitoring, and impact of reduced ADAMTS13 activity on end organ damage. This review discusses monitoring and treatment strategy for long-term management of TTP, including the variety of therapies available to maintain remission, prevent relapse and a summary of a long-term treatment pathway.

Interventions for atypical haemolytic uraemic syndrome

BACKGROUND

Atypical haemolytic uraemic syndrome (aHUS) is a rare disorder characterised by thrombocytopenia, microangiopathic haemolytic anaemia, and acute kidney injury. The condition is primarily caused by inherited or acquired dysregulation of complement regulatory proteins with ~40% of those affected aged < 18 years. Historically, kidney failure and death were common outcomes, however, improved understanding of the condition has led to discovery of novel therapies.

OBJECTIVES

To evaluate the benefits and harms of interventions for aHUS.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies for randomised controlled studies (RCTs) up to 3 September 2020 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. MEDLINE(OVID) 1946 to 27 July 2020 and EMBASE (OVID) 1974 to 27 July 2020 were searched for non-RCTs.

SELECTION CRITERIA

All randomised and non-randomised clinical trials comparing an intervention with placebo, an intervention with supportive therapy, or two or more interventions for aHUS were included. Given the rare nature of the condition in question, prospective single-arm studies of any intervention for aHUS were also included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted pre-specified data from eligible studies and evaluated risk of bias using a newly developed tool based on existing Cochrane criteria. As statistical meta-analysis was not appropriate, qualitative analysis of data was then performed.

MAIN RESULTS

We included five single-arm studies, all of which evaluated terminal complement inhibition for the treatment of aHUS. Four studies evaluated the short-acting C5 inhibitor eculizumab and one study evaluated the longer-acting C5 inhibitor ravulizumab. All included studies within the review were of non-randomised, single-arm design. Thus, risk of bias is high, and it is challenging to draw firm conclusions from this low-quality evidence. One hundred patients were included within three primary studies evaluating eculizumab, with further data reported from 37 patients in a secondary study. Fifty-eight patients were included in the ravulizumab study. After 26 weeks of eculizumab therapy there were no deaths and a 70% reduction in the number of patients requiring dialysis. Complete thrombotic microangiopathic (TMA) response was observed in 60% of patients at 26 weeks and 65% at two years. After 26 weeks of ravulizumab therapy four patients had died (7%) and complete TMA response was observed in 54% of patients. Substantial improvements were seen in estimated glomerular filtration rate and health-related quality of life in both eculizumab and ravulizumab studies. Serious adverse events occurred in 42% of patients, and meningococcal infection occurred in two patients, both treated with eculizumab.

AUTHORS' CONCLUSIONS

When compared with historical data, terminal complement inhibition appears to offer favourable outcomes in patients with aHUS, based upon very low-quality evidence drawn from five single-arm studies. It is unlikely that an RCT will be conducted in aHUS and therefore careful consideration of future single-arm data as well as longer term follow-up data will be required to better understand treatment duration, adverse outcomes and risk of disease recurrence associated with terminal complement inhibition.

Plasma exchange and thrombotic microangiopathies: From pathophysiology to clinical practice

Thrombotic microangiopathy (TMA) brings together many diseases that have a commonality in the apparition of mechanical hemolysis with consuming thrombopenia. In all cases, these diseases can be life threatening, thereby justifying the implementation of treatment as an emergency. First-line treatment represents plasma exchange. This treatment has proven efficiency in improving the vital patient's and functional prognosis. However, the administration methods of plasma exchange can be redefined in light of the understanding of the pathophysiology of TMA. The aim of this review is to try to define, from pathophysiology, the place of plasma exchanges in the modern therapeutic arsenal of TMA.

Thrombotic thrombocytopenic purpura developed during the conservative treatment of anti-phospholipase A2 receptor antibody-positive idiopathic membranous nephropathy: a case report

Background

Idiopathic membranous nephropathy (MN) is one of the major glomerulonephritis that cause nephrotic syndrome. The phospholipase A₂ receptor (PLA₂R) has recently been identified as an endogenous antigen of idiopathic MN. Thrombotic thrombocytopenic purpura (TTP) is a disorder characterized by schistocytes, hemolytic anemia, thrombocytopenia, and organ dysfunction which occurs as a result of thrombi. Patients with acquired TTP have autoantibodies against a disintegrin and metalloprotease with thrombospondin type 1 motif 13 (ADAMTS13). These autoantibodies act as an inhibitor and cause ADAMTS13 deficiency. Idiopathic MN and acquired TTP are usually considered as independent autoimmune diseases. We experienced a patient who developed TTP during the conservative treatment of idiopathic MN, with the coexistence of ADAMTS13 inhibitor and anti-PLA₂R antibody.

Case presentation

A 73-year-old man presented with thrombocytopenia, hemolytic anemia, disturbance of consciousness, and acute kidney injury after 4-year course of biopsy-proven idiopathic MN. ADAMTS13 activity was undetectable and the ADAMTS13 inhibitor was identified. Additionally, he was positive for anti-PLA₂R antibody. The patient did not have any diseases that could cause secondary thrombotic microangiopathy, and he was diagnosed with acquired TTP. Steroid therapy and plasma exchange were initiated and the acquired TTP resolved. MN achieved remission 3 months after the anti-PLA₂R antibody disappeared.

Conclusions

This is the first reported case of acquired TTP developed during conservative treatment of idiopathic MN, with both ADAMTS13 inhibitor and anti-PLA₂R antibody positive at the onset of the TTP. The present case suggests that idiopathic MN might be associated with the development of some cases of acquired TTP.

Atypical haemolytic-uraemic syndrome in patient with metastatic colorectal cancer treated with fluorouracil and oxaliplatin: a case report and a review of literature

Background. Thrombotic microangiopathies (TMA) are relatively rare but severe disorders characterised by non-immune haemolytic anaemia, thrombocytopaenia and organ failure. In patients with metastatic cancer, sporadic forms of TMA can be triggered by chemotherapeutic agents or can occur as complication of malignancy itself or of infections.

Case report. Hereby, we report a case of a patient diagnosed with metastatic colorectal cancer who experienced an atypical haemolytic-uraemic syndrome (aHUS) during chemotherapy treatment with FOLFOX6 scheme. The use of eculizumab led to prompt recovery of laboratory parameters that was maintained despite treatment discontinuation due to appearance of pneumonia infectious. Additionally, genetic analyses revealed the presence in heterozygosis of CFH gene polymorphisms associated with aHUS.

Conclusion. This case emphasises the importance of considering TMA as a possible diagnosis in patients with cancer presenting with haemolytic non-immune mediate anaemia and thrombocytopaenia associated with worsening of renal function. Prompt diagnosis is crucial for the requirement of its specific treatment that can impact on long-term outcome and prognosis.

Plasma Therapies in Thrombotic Syndromes

Background

Plasma therapies are being applied to thombotic syndromes, but there are limited controlled studies.

Objective

To review the evidence and the current practices for plasma therapies in thrombotic syndromes.

Methods

Expert-enhanced evidence-based analysis. Evidence obtained as of Dec 31, 2002 using Pub Med electronic reference library and expert-obtained library for a total of > 3,000 references obtained using the terms plasma therapy or plasma exchange or plasmapheresis or plasmafiltration or sorbents each combined with the words thrombotic syndrome or sepsis or septic shock. The authors screened the abstracts, reviewed the agreed set of papers, and compiled the recommendations.

Results

Plasma therapies, which alter the plasma components in patients, have been applied in thrombotic syndromes worldwide. In these patients, there is a biologic plausibility for plasma therapies since they have molecules that are prothrombotic and/or antifibrinolytic which would put them at risk for microvascular thrombosis and end-organ damage. There are respectively one randomized controlled trial (RCT) in primary thrombotic syndrome, and secondary thrombotic syndrome, which showed an improvement in mortality in applying plasma therapies (plasma exchange by centrifugation). However, there are numerous non-randomized and case series. Plasma exchange is accepted as the standard therapy for primary thrombotic syndrome as in thrombotic thrombocytopenic purpura (TTP). However, no consensus has been reached for plasma exchange in secondary thrombotic syndromes such as in sepsis, hemolytic uremic syndrome (HUS), thrombocytopenia associated multiple organ failure, TTP/HUS, s/p bone marrow or solid organ transplant, HELLP syndrome, immunologic disorders, drug exposure, or pancreatitis.

Conclusions

As we understand more about the pathophysiology of thrombotic syndromes, specific plasma therapies can be applied for the specific need of a particular patient population. There are sufficient preliminary data to recommend a definitive RCT to evaluate the efficacy of the different types of plasma therapies in secondary thrombotic syndromes.

Use of Cellular and Plasma Apheresis in the Critically Ill Patient: Part II: Clinical Indications and Applications

Apheresis is the process of separating the blood and removing or manipulating a cellular or plasma component for therapeutic benefit. Such procedures may be indicated in the critical care setting as primary or adjunctive therapy for certain hematologic, neurologic, renal, and autoimmune/rheumatologic disorders. In part I of this series, the technical aspects of apheresis were described and the physiologic rationale and clinical considerations were discussed. This review highlights the pathophysiologic basis, specific clinical indications, and treatment parameters for disorders that more commonly require management in the intensive care unit. The choice of plasma or cellular apheresis in these cases is guided by wellaccepted, evidence-based clinical treatment guidelines. For some disorders, such as liver failure, severe sepsis, and multiple-organ dysfunction syndrome, apheresis treatment approaches remain experimental. Ongoing studies are investigating the potential utility of conventional plasma exchange, ex vivo plasma manipulation, and newer technologies for these and other disorders in severely ill patients.

Liver transplantation for aHUS: still needed in the eculizumab era?

BACKGROUND

The risk of disease recurrence after a kidney transplant is high in patients with atypical hemolytic uremic syndrome (aHUS) and mutations in the complement factor H (FH) gene (CFH). Since FH is mostly produced by the liver, a kidney transplant does not correct the genetic defect. The anti-C5 antibody eculizumab prevents post-transplant aHUS recurrence, but it does not cure the disease. Combined liver-kidney transplantation has been performed in few patients with CFH mutations based on the rationale that liver replacement provides a source of normal FH.

METHODS

We report the 9-year follow-up of a child with aHUS and a CFH mutation, including clinical data, extensive genetic characterization, and complement profile in the circulation and at endothelial level. The outcome of kidney and liver transplants performed separately 3 years apart are reported.

RESULTS

The patient showed incomplete response to plasma, with relapsing episodes, progression to end-stage renal disease, and endothelial-restricted complement dysregulation. Eculizumab prophylaxis post-kidney transplant did not achieve sustained remission, leaving the child at risk of disease recurrence. A liver graft given 3 years after the kidney transplant completely abrogated endothelial complement activation and allowed eculizumab withdrawal.

CONCLUSIONS

Liver transplant may definitely cure aHUS and represents an option for patients with suboptimal response to eculizumab.

Re-examination of 30-day survival and relapse rates in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome

BACKGROUND AND OBJECTIVES

Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are characterized by microangiopathic hemolytic anemia and thrombocytopenia. Interestingly, markedly different survival rates have been reported despite increases in survivability. We studied TTP-HUS 30-day mortality and relapse rates of patients who received TPE at our institution and compared them to published data.

PATIENTS AND METHODS

Retrospective study analyzed 30-day mortality and relapse rates attributed to TTP-HUS from 01/01/2008 to 12/31/2012 and compared them to comparable literature reporting mortality and survival. Studies describing other etiologies for TPE and different mortality time interval were excluded.

RESULTS

Fifty-nine patients were analyzed and all were initially treated with TPE and corticosteroids. Eleven patients were classified as not having TTP-HUS due to testing or clinical reassessment which ruled in other etiologies, and 18/59 patients had ADAMTS13 activity <10%. Of remaining patients, 36/48 (75%) were diagnosed as idiopathic and 12/48 (25%) as secondary TTP-HUS. Patients received a mean of 12 TPEs (range 1-42); 42/48 (87.5%) patients had ADAMTS13 activity measured; complete response obtained in 39/48 (81.2%) patients (platelet count >100 x 10(9)/L); partial response in 4/48 (8%); and 5/48 (10.4%) did not have increases in platelet counts (2/5 of these patients died within the study period). Forty percent of patients obtained platelet counts >150 x 10(9)/L. Overall 30-day mortality for our patient cohort was 6.7% (4/59). Comparison of our mortality rate to combined data of five published studies of 16% (92/571) showed a significant difference, p = 0.04. Our relapse rate was 18.6% (11/59) similar to previous reports.

CONCLUSIONS

Wide differences in mortality may be due to grouping of two distinct pathologic entities under TTP-HUS; and presence of confounding factors in the patient populations under study such as co-morbidities, promptness of TPE initiation, delay in diagnosis and therapeutic practice.

Does corticosteroid treatment cause prolonged recovery and increased total bilirubin level in severe ADAMTS-13-deficient TTP patient?

A 41-year-old female patient complaining of fatigue, headache, mild confusion, and rush on her lower extremities was admitted to our emergency department. Laboratory tests revealed that he had anemia, thrombocytopenia, and increased levels of indirect bilirubin and lactic dehydrogenase (LDH) in blood tests. Direct and indirect Coombs tests were negative, and fragmented erythrocytes were observed in peripheral blood smears. The patient was diagnosed with thrombotic thrombocytopenic purpura (TTP). The best supportive care was provided. Therapeutic plasma exchange (TPE) and 1 mg/kg methylprednisolone treatments were administered. On the 10th day of treatment, LDH level and fragmented red blood cells in peripheral blood smear were decreased, but his direct and indirect bilirubin levels increased despite the fact that he was treated with 1 mg/kg methylprednisolone and TPE. The patient had severe ADAMTS-13 deficiency. After discontinued steroids treatment, his bilirubin level normalized within 4 days. On the 4th day after bilirubin level normalized, vincristine treatment was administered. TPE was also continued. There was no consensus about the optimal schedule for discontinuing plasmapheresis therapy, and also we observed total bilirubin level improvement with discontinued corticosteroid treatment. In this case, corticosteroid treatment was linked with the increase of total bilirubin level in severe ADAMTS-13-deficient TTP patient.

Diagnosis and management of atypical hemolytic uremic syndrome in children: single centre experience

Atypical hemolytic uremic syndrome (aHUS) although rare is the commonest cause of acute renal failure (ARF) in children and has poor prognosis. We present single centre experience of aHUS. Thirty six children (29 males, 7 females) with mean age, 7.9 years presented with ARF, 2 children also had tonic-clonic type convulsions. Their hematology examination revealed hemolytic anemia with s. creatinine (SCr), 5.54 mg/dl. Acute HUS was observed in 75 %, acute on chronic HUS in 19.4 % and patchy cortical necrosis (PCN) in 5.6 % biopsies. Mean 5.4 plasma exchanges (PE) were carried out. Supportive management of anti-hypertensives and prednisone was also given. Recovery end points were establishment of urine output, improvement of SCr and hematological profile. Hematology and renal function profile improved variably in all children, 5.6 % died, relapse was observed in 80.5 % over mean 70 days; 13.9 % children are doing well over mean follow-up of 268.8 days. Thus poor prognosis was observed in 86.1 % children. Children with acute on chronic HUS and PCN did not recover. Six children who recovered had acute HUS. aHUS in Indian children occurs at an older age of around 8 years and chronic/irreversible changes on histopathology examination are harbingers of poor prognosis. PE is life-saving however further research for developing strategies to improve long-term survival is needed.

Risk factors and clinical profile of thrombotic thrombocytopenic purpura in systemic lupus erythematosus patients. Is this a distinctive clinical entity in the thrombotic microangiopathy spectrum?: a case control study

INTRODUCTION

The association of thrombotic thrombocytopenic purpura (TTP) with systemic lupus erythematosus (SLE) is rare. It is associated with high morbidity and mortality. Information about risk factors and clinical outcomes is scant.

MATERIAL AND METHODS

A retrospective case-control study was performed in a referral center in Mexico City between 1994 and 2013. Patients were diagnosed with TTP if they fulfilled the following criteria: microangiopathic haemolytic anaemia, thrombocytopenia, high LDH levels, normal fibrinogen and negative Coombs' test. Patients with SLE were diagnosed with ≥ 4 ACR criteria. We included three study groups: group A included patients with SLE-associated TTP (TTP/SLE; cases n = 22, TTP events n = 24); patients with non-autoimmune TTP (NA-TTP; cases n = 19, TTP events n = 22) were included in group B and patients with SLE without TTP (n = 48) in group C.

RESULTS

After multivariate analysis, lymphopenia < 1000/mm3 [OR 19.84, p = 0.037], high SLEDAI score three months prior to hospitalisation [OR 1.54, p = 0.028], Hg <7g/dL [OR 6.81, p = 0.026], low levels of indirect bilirubin [OR 0.51, p = 0.007], and less severe thrombocytopenia [OR 0.98, p = 0.009] were associated with TTP in SLE patients. Patients with TTP/SLE received increased cumulative steroid dose vs. NA-TTP (p = 0.006) and a higher number of immunosuppressive drugs (p = 0.015). Patients with TTP/SLE had higher survival than NA-TTP (p=0.033); however, patients hospitalised for TTP/SLE had a higher risk of death than lupus patients hospitalised for other causes

CONCLUSIONS

Lymphopenia is an independent risk factor for TTP/SLE. It is likely that patients with TTP/SLE present with less evident clinical features, so the level of suspicion must be higher to avoid delay in treatment.

Macrovascular thrombosis in critically ill patients with thrombotic micro-angiopathies

The purpose of this study is to assess the incidence and describe the clinical and pathological features of macrovascular thrombosis during the course of thrombotic micro-angiopathy (TMA) in a 6 year retrospective study of all adults with TMA, admitted to a teaching-hospital ICU. Of the 55 patients identified, all had anaemia and thrombocytopenia and 45 (82 %) had renal or neurological impairment. All patients received plasmapheresis, steroids, and strict blood pressure control. Macrovascular venous or arterial thromboses were diagnosed in 28 (51 %) patients; among them, 7 had cerebral artery thrombosis and 21 (including 13 with central venous catheters) had deep vein thrombosis. Median time from plasmapheresis initiation to thrombosis was 7 (4-10) days. Clinical findings were suggestive of deep venous thrombosis in 7 of the 21 patients (33 %) and only one of the 7 patients with stroke had corresponding clinical signs. By multivariate analysis, factors independently associated with macrovascular thrombosis were undetectable ADAMTS13 activity (odds ratio 7.33, 95 % confidence interval 1.3-41.3), cardiac involvement with TMA (odds ratio, 3.46; 95 % confidence interval, 1.1-13.9) and TMA flare (odds ratio 9.03; 95 % confidence interval 1.03-79.4). In conclusion, half of the patients with TMA experience macrovascular thrombosis. Patients with TTP-related ADAMTS13 deficiency and those with cardiac manifestations of TMA are at higher risk for arterial or deep venous thrombosis.

Tacrolimus-induced thrombotic microangiopathy in orthotopic liver transplant patients: case series of four patients

Thrombotic microangiopathy (TMA) is a potentially fatal complication in solid organ and bone marrow transplant patients, with reported incidence of 0.5-3% and mortality of about 75%. To emphasise the importance of early diagnosis and prompt commencement of therapy results in improved clinical outcomes. A retrospective study of all patients who underwent orthotopic liver transplantation (OLTX) at the Western Australian Liver Transplantation Service from May 1994 to December 2010 was conducted to identify patients who developed tacrolimus-induced TMA. We identified four patients with tacrolimus-induced TMA post-OLTX, derived from a cohort of 104 patients treated with tacrolimus in our institution. The mean age at diagnosis was 40 years, and the mean time of onset was 63 ± 7.5 weeks after OLTX. The indications for OLTX in the four patients were fulminant hepatic failure in three (Wilson disease, paracetamol overdose and post-partum thrombotic thrombocytopenic purpura) and hepatitis C virus-related cirrhosis. All patients had tacrolimus post-OLTX. At diagnosis, tacrolimus was discontinued in all patients, and three of the four patients underwent plasma exchange and all patients improved clinically. Mean duration of follow up was 15 ± 7.5 months. There was no mortality 6 months post-TMA. Early diagnosis with immediate discontinuation or conversion of calcineurin inhibitors and plasma exchange should be offered to OLTX patients with TMA as it results in good outcomes.

Monogenic diseases that can be cured by liver transplantation

While the prevalence of most diseases caused by single-gene mutations is low and defines them as rare conditions, all together, monogenic diseases account for approximately 10 in every 1000 births according to the World Health Organisation. Orthotopic liver transplantation (LT) could offer a therapeutic option in monogenic diseases in two ways: by substituting for an injured liver or by supplying a tissue that can replace a mutant protein. In this respect, LT may be regarded as the correction of a disease at the level of the dysfunctional protein. Monogenic diseases that involve the liver represent a heterogeneous group of disorders. In conditions associated with predominant liver parenchymal damage (i.e., genetic cholestatic disorders, Wilson's disease, hereditary hemochromatosis, tyrosinemia, α1 antitrypsin deficiency), hepatic complications are the major source of morbidity and LT not only replaces a dysfunctional liver but also corrects the genetic defect and effectively cures the disease. A second group includes liver-based genetic disorders characterised by an architecturally near-normal liver (urea cycle disorders, Crigler-Najjar syndrome, familial amyloid polyneuropathy, primary hyperoxaluria type 1, atypical haemolytic uremic syndrome-1). In these defects, extrahepatic complications are the main source of morbidity and mortality while liver function is relatively preserved. Combined transplantation of other organs may be required, and other surgical techniques, such as domino and auxiliary liver transplantation, have been attempted. In a third group of monogenic diseases, the underlying genetic defect is expressed at a systemic level and liver involvement is just one of the clinical manifestations. In these conditions, LT might only be partially curative since the abnormal phenotype is maintained by extrahepatic synthesis of the toxic metabolites (i.e., methylmalonic acidemia, propionic acidemia). This review focuses on principles of diagnosis, management and LT results in both paediatric and adult populations of selected liver-based monogenic diseases, which represent examples of different transplantation strategies, driven by the understanding of the expression of the underlying genetic defect.

Therapeutic plasma exchange in patients with thrombotic thrombocytopenic purpura: a retrospective multicenter study

Thrombotic thrombocytopenic purpura (TTP) is a particular form of thrombotic microangiopathy typically characterized by thrombocytopenia, microangiopathic hemolytic anemia, fever, neurological abnormalities, and renal dysfunction. TTP requires a rapid diagnosis and an adapted management in emergency. Daily sessions of therapeutic plasma exchange (TPE) remain the basis of management of TTP. Also, TTP is a rare disease that is fatal if it is not treated. TPE has resulted in excellent remission and survival rates in TTP patients.

AIM

We aimed to present our experience in 163 patients with TTP treated with TPE during the past 5years from 10 centers of Turkey.

PATIENTS AND METHODS

One hundered and sixty-three patients with TTP treated with TPE during the past 5years from 10 centers of Turkey were retrospectively evaluated. TPE was carried out 1-1.5times plasma volume. Fresh frozen plasma (FFP) was used as the replacement fluid. TPE was performed daily until normalization of serum lactate dehydrogenase (LDH) and recovery of the platelet count to >150×10(9)/dL. TPE was then slowly tapered. Clinical data, the number of TPE, other given therapy modalities, treatment outcomes, and TPE complications were recorded.

RESULTS

Fifty-eight percent (95/163) of the patients were females. The median age of the patients was 42years (range; 16-82). The median age of male patients was significantly higher than female (53 vs. 34years; p<0.001). All patients had thrombocytopenia and microangiopathic hemolytic anemia. At the same time, 82.8% (135/163) of patients had neurological abnormalities, 78.5% (128/163) of patients had renal dysfunction, and 89% (145/163) of patients had fever. Also, 10.4% (17/163) of patients had three of the five criteria, 10.4% (17/163) of patients had four of the five criteria, and 6.1% (10/163) of patients had all of the five criteria. Primary TTP comprised of 85.9% (140/163) of the patients and secondary TTP comprised of 14.1% (23/163) of the patients. Malignancy was the most common cause in secondary TTP. The median number of TPE was 13 (range; 1-80). The number of TPE was significantly higher in complete response (CR) patients (median 15.0 vs. 3.5; p<0.001). CR was achieved in 85.3% (139/163) of the patients. Similar results were achieved with TPE in both primary and secondary TTP (85% vs. 87%, respectively; p=0.806). There was no advantage of TPE+prednisolone compared to TPE alone in terms of CR rates (82.1% vs. 76.7%; p=0.746). CR was not achieved in 14.7% (24/163) of the patients and these patients died of TTP related causes. There were no statistical differences in terms of mortality rate between patients with secondary and primary TTP [15% (21/140) vs. 13% (3/23); p=0.806]. But, we obtained significant statistical differences in terms of mortality rate between patients on TPE alone and TPE+prednisolone [14% (12/86) vs. 3% (2/67), p<0.001].

CONCLUSIONS

TPE is an effective treatment for TTP and is associated with high CR rate in both primary and secondary TTP. Thrombocytopenia together with microangiopathic hemolytic anemia is mandatory for the diagnosis of TTP and if these two criteria met in a patient, TPE should be performed immediately.

Acute Progression of Adult-Onset Atypical Hemolytic-Uremic Syndrome due to CFH Mutation: A Case Report

Atypical hemolytic-uremic syndrome (aHUS), unlike typical HUS, is not due to bacteria but rather to an idiopathic or genetic cause that promotes dysregulation of the alternative complement pathway. It leads to hemolytic anemia, thrombocytopenia, and renal impairment. Although aHUS secondary to a genetic mutation is relatively rare, when occurring due to a mutation in Factor H (CFH), it usually presents with younger onset and has a more severe course, which in the majority ends with end-stage renal failure. Paradoxically to most available data, our case features acute aHUS due to a CFH mutation with late onset (38-year-old) and rapid progression to end-stage renal disease. Due to current data indicating a high risk of graft failure in such patients, the diagnosis of aHUS secondary to a genetic cause has disqualified our patient from a living (family) donor renal transplantation and left her with no other option but to begin permanent renal replacement therapy.

ADAMTS-13 activity and autoantibodies classes and subclasses as prognostic predictors in acquired thrombotic thrombocytopenic purpura

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a rare life-threatening disease. Of surviving patients, 45% develops an exacerbation or a late recurrence. Severe ADAMTS-13 deficiency, both during the acute episode and remission, is a well-established predictor of recurrence. The predictive value of anti-ADAMTS-13 antibodies, their inhibitory activity and Ig class subtype for disease recurrence is still to be established.

OBJECTIVES

To analyze ADAMTS-13-related biomarkers (ADAMTS-13 and anti-ADAMTS-13 immunoglobulins, classes and subclasses) and their potential relationship with prognosis.

PATIENTS/METHODS

In 115 patients with TTP, we assessed the association between levels of these biomarkers and the severity of acute episodes; we analysed also the hazard ratio (HR) and 95% confidence interval (CI) of recurrence in association with biomarkers levels retrieved at the previous acute episode or during remission, using Cox regression models.

RESULTS

During the acute phase, higher IgA, IgG1 and IgG3 titers showed the strongest association with acute episode severity. In the survival analyzes, the only biomarker significantly associated with a high hazard of recurrence after an acute episode was the presence of IgG. Conversly, low ADAMTS-13 activity or antigen levels (<10%), the presence of ADAMTS-13 inhibitor or IgG during remission were all significantly associated with a higher hazard of recurrence.

CONCLUSIONS

Both the Ig class and subclass are of predictive value for acute episode severity in patients with TTP. Although markers that could predict the risk of recurrence in the acute phase are limited, a thorough assessment of ADAMTS-13-related parameters during remission is warranted.

Development and validation of a predictive model for death in acquired severe ADAMTS13 deficiency-associated idiopathic thrombotic thrombocytopenic purpura: the French TMA Reference Center experience

BACKGROUND

Acquired thrombotic thrombocytopenic purpura is still associated with a 10-20% death rate. It has still not been possible to clearly identify early prognostic factors of death. This study involved thrombotic thrombocytopenic purpura patients with acquired severe (<10% of normal activity) ADAMTS13 deficiency and aimed to identify prognostic factors associated with 30-day death.

DESIGN AND METHODS

The study involved a prospective cohort of patients and was carried out between October 2000 and August 2010. A validation cohort of patients was set up from September 2010 to August 2011. Altogether, 281 (analysis cohort) and 66 (validation cohort) consecutive adult thrombotic thrombocytopenic purpura patients with acquired severe ADAMTS13 deficiency were enrolled. The study evaluated 30-day mortality after treatment initiation according to characteristics at inclusion.

RESULTS

Non-survivors (11%) were older (P=10(-6)) and more frequently presented arterial hypertension (P=5.10(-4)) and ischemic heart disease (P=0.013). Prognosis was increasingly poor with age (P=0.004). On presentation, cerebral manifestations were more frequent in non-survivors (P=0.018) and serum creatinine level was higher (P=0.008). The most significant independent variables determining death were age, severe cerebral involvement and LDH level 10 N or over. A 3-level risk score for early death was defined and confirmed in the validation cohort using these variables, with higher values corresponding to increased risk of early death.

CONCLUSIONS

A risk score for early death was defined in patients with thrombotic thrombocytopenic purpura and validated on an independent cohort. This score should help to stratify early treatment and identify patients with a worse prognosis.

Indicators of acute and persistent renal damage in adult thrombotic microangiopathy

Background

Thrombotic microangiopathies (TMA) in adults such as thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are life-threatening disorders if untreated. Clinical presentation is highly variable and prognostic factors for clinical course and outcome are not well established.

Methods

We performed a retrospective observational study of 62 patients with TMA, 22 males and 40 females aged 16 to 76 years, treated with plasma exchange at one center to identify clinical risk factors for the development of renal insufficiency.

Results

On admission, 39 of 62 patients (63%) had acute renal failure (ARF) with 32 patients (52%) requiring dialysis treatment. High systolic arterial pressure (SAP, p = 0.009) or mean arterial pressure (MAP, p = 0.027) on admission was associated with acute renal failure. Patients with SAP>140 mmHg on admission had a sevenfold increased risk of severe kidney disease (OR 7.464, CI 2.097–26.565). MAP>100 mmHg indicated a fourfold increased risk for acute renal failure (OR 4.261, CI 1.400–12.972). High SAP, diastolic arterial pressure (DAP), and MAP on admission were also independent risk factors for persistent renal insufficiency with the strongest correlation for high MAP. Moreover, a high C-reactive protein (CRP) level on admission correlated with renal failure in the course of the disease (p = 0.003). At discharge, renal function in 11 of 39 patients (28%) had fully recovered, 14 patients (23%) remained on dialysis, and 14 patients (23%) had non-dialysis-dependent chronic kidney disease. Seven patients (11%) died. We identified an older age as risk factor for death.

Conclusions

High blood pressure as well as high CRP serum levels on admission are associated with renal insufficiency in TMA. High blood pressure on admission is also a strong predictor of sustained renal insufficiency. Thus, adult TMA patients with high blood pressure may require special attention to prevent persistent renal failure.

Platelet count and prothrombin time help distinguish thrombotic thrombocytopenic purpura-hemolytic uremic syndrome from disseminated intravascular coagulation in adults

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) and disseminated intravascular coagulation (DIC) may have identical manifestations in adults. Because TTP-HUS is 90% fatal without plasma exchange, prompt diagnosis is essential. To test the hypothesis that routine laboratory assays can discriminate between the 2 entities, we retrospectively identified adult patients with TTP-HUS and matched each with 2 patients with DIC. Although the platelet count, prothrombin time (PT), and partial thromboplastin time were different (P < .05) between the 2 patient groups, after regression analysis, only PT and profound thrombocytopenia remained associated with TTP-HUS (P = .001 and P = .003, respectively). A platelet count of less than 20 x 10(3)/microL (20 x 10(9)/L) and a PT within 5 seconds of the upper limit of the reference interval had a specificity of 92% for TTP-HUS. Our data confirm that readily available laboratory assays in the proper clinical scenario can increase the likelihood of TTP-HUS over DIC.

Thrombotic thrombocytopenic purpura at the Johns Hopkins Hospital from 1992 to 2008: clinical outcomes and risk factors for relapse

BACKGROUND

Plasma exchange, the standard treatment for thrombotic thrombocytopenic purpura (TTP), has significantly decreased disease mortality. However, TTP recurs in 20% to 50% of patients who survive the initial episode. We aimed to describe the clinical spectrum of TTP, to determine the valid endpoint for plasma exchange cessation, and to explore the risk factors for disease relapse.

STUDY DESIGN AND METHODS

Using the ICD-9 diagnosis code, we identified patients treated for TTP at the Johns Hopkins Hospital between 1992 and 2008. Complete demographic, clinical, laboratory, treatment, and outcome data were collected from the medical records.

RESULTS

A total of 72 patients were treated for 134 episodes of TTP at the Johns Hopkins Hospital during the study period. With standardized combined immunosuppression and plasma exchange treatment, the all-cause mortality rate was 4%. Lactate dehydrogenase (LDH) normalization lagged behind platelet (PLT) recovery by an average of 9 days and did not predict response. Relapse occurred in 36% of patients during a median follow-up of 30 months with most (76%) occurring in the first 24 months. African American ethnicity was associated with increased risk of relapse (odds ratio = 4.8, p = 0.03).

CONCLUSIONS

Excellent outcomes in patients with TTP are achievable with multimodality therapy. LDH normalization lags behind PLT recovery and might not be an informative endpoint for plasma exchange cessation. Prospective studies are warranted to confirm the influence of race on relapse and identify additional risk factors for adverse outcomes that could be targeted to improve therapeutic outcomes for patients with TTP.

Clinical outcomes after platelet transfusions in patients with thrombotic thrombocytopenic purpura

BACKGROUND

Reports of deterioration and death after platelet (PLT) transfusions in patients with thrombotic thrombocytopenic purpura (TTP) have led to recommendations that they should not be given except for life-threatening hemorrhage.

STUDY DESIGN AND METHODS

Published reports of PLT transfusions in patients with TTP were systematically reviewed and data from the Oklahoma TTP-HUS Registry, an inception cohort of 382 consecutive patients, 1989 through 2007, were analyzed.

RESULTS

A systematic review identified 34 publications describing outcomes of patients with TTP after PLT transfusions: 9 articles attributed complications to PLT transfusions, 4 suggested that they may be safe, and 21 articles did not comment about a relation between PLT transfusions and outcomes. Fifty-four consecutive patients from the Oklahoma TTP-HUS Registry were prospectively analyzed. ADAMTS13 activity was less than 10 percent in 47 patients; also included were 7 patients whose activity was not measured but who may have been deficient. Thirty-three (61%) patients received PLT transfusions. The frequency of death was not different between the two groups (p = 0.971): 8 (24%) patients who received PLT transfusions died (thrombosis, 5; hemorrhage, 1; sepsis, 2) and 5 (24%) patients who did not receive PLT transfusions died (thrombosis, 4; hemorrhage, 1). The frequency of severe neurologic events was also not different (p = 0.190): 17 (52%) patients who received PLT transfusions (in 5 of these 17 patients, neurologic events only occurred before PLT transfusions) and 7 (33%) patients who did not receive PLT transfusions.

CONCLUSION

Evidence for harm from PLT transfusions in patients with TTP is uncertain.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS): a 24-year clinical experience with 178 patients

Background

Thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome (TTP-HUS) are related and uncommon disorders with a high fatality and complication rate if untreated. Plasma exchange therapy has been shown to produce high response rates and improve survival in patients with many forms of TTP-HUS. We performed a retrospective cohort study of 178 consecutively treated patients with TTP-HUS and analyzed whether clinical or laboratory characteristics could predict for important short- and long-term outcome measures.

Results

Overall 30-day mortality was 16% (n = 27). 171 patients (96%) received plasma exchange as the principal treatment, with a mean of 8 exchanges and a mean cumulative infused volume of 42 ± 71 L of fresh frozen plasma. The rate of complete response was 65% or 55% depending on whether this was defined by a platelet count of 100,000/μl or 150,000/μl, respectively. The rate of relapse was 18%. The Clinical Severity Score did not predict for 30-day mortality or relapse. The time to complete response did not predict for relapse. Renal insufficiency at presentation was associated with a decreased risk of relapse, with each unit increase in serum creatinine associated with a 40% decreased odds of relapse. 72% of our cohort had an idiopathic TTP-sporadic HUS, while 17% had an underlying cancer, received a solid organ transplant or were treated with a mitomycin-based therapy. The estimated overall 5-year survival was 55% and was significantly better in those without serious underlying conditions.

Conclusion

Plasma exchange therapy produced both high response and survival rates in this large cohort of patients with TTP-HUS. The Clinical Severity Score did not predict for 30-day mortality or relapse, contrary to our previous findings. Interestingly, the presence of renal insufficiency was associated with a decreased risk of relapse. The most important predictor of mortality was the presence or absence of a serious underlying disorder.

Translational mini-review series on complement factor H: therapies of renal diseases associated with complement factor H abnormalities: atypical haemolytic uraemic syndrome and membranoproliferative glomerulonephritis

Genetic and acquired abnormalities in complement factor H (CFH) have been associated with two different human renal diseases: haemolytic uraemic syndrome and membrano proliferative glomerulonephritis. The new genetic and pathogenetic findings in these diseases and their clinical implications for the management and cure of patients are reviewed in this paper.

Where next with atypical hemolytic uremic syndrome?

Hemolytic uremic syndrome (HUS) is a systemic disease characterized by damage to endothelial cells, erythrocytes and kidney glomeruli. A "typical" form of HUS follows gastrointestinal infection with enterohemorrhagic E. coli (e.g. O157:H7). Atypical HUS (aHUS) is not associated with gastrointestinal infections but is sporadic or familial in nature. Approximately 50% of aHUS cases are associated with a mutation in one or more genes coding for proteins involved in regulation or activation of the alternative pathway of complement. The link between the disease and the mutations shows the important balance of the alternative pathway between activation and regulation on host cell surfaces. It also demonstrates the power of this pathway in destroying cellular targets in general. In this review we discuss the current knowledge on pathogenesis, classification, diagnostics and management of this disease. We indicate a comprehensive diagnostic approach for aHUS based on the latest knowledge on complement dysregulation to gain both immediate and future patient benefit by assisting in choosing more appropriate therapy for each patient. We also indicate directions in which therapy of aHUS might improve and indicate the need to re-think the terminology and categorisation of the HUS-like diseases so that any advantage in the understanding of complement regulatory problems can be applied to patients accurately.

[Thrombotic microangiopathies. Incidence, pathogenesis, diagnosis, treatment and prognosis]

INTRODUCTION

The objective of this work was to review current data about the pathophysiology, clinical features, and treatment of thrombotic microangiopathies.

CURRENT KNOWLEDGE

Thrombotic microangiopathies are microvascular occlusive disorders characterized by systemic or intrarenal aggregation of platelets, thrombocytopenia, and mechanical injury to erythrocytes. In thrombotic thrombocytopenic purpura, systemic microvascular aggregation of platelets causes ischemia in the brain and other organs. In the hemolytic-uremic syndrome, platelet-fibrin thrombi occlude predominantly the renal circulation. Thrombotic microangiopathy is a rare disorder whose varied clinical manifestations result from the formation of platelet-rich thrombi within the microvasculature and consequent tissue ischemia. The clinical features are acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. This diagnosis is of considerable importance because of the possible fulminant clinical course. Some atypical forms may be unrecognized. Plasma exchange is the current reference treatment of thrombotic thrombocytopenic purpura. However, in the light of recent publications, either infusions of concentrates of purified enzyme or more intensive immunosuppressive therapy would be more specific.

Therapeutic plasma exchange plus corticosteroid for the treatment of the thrombotic thrombocytopenic purpura: a single institutional experience in the southern Marmara region of Turkey

Thrombotic thrombocytopenic purpura (TTP) is a classic, but not a common disorder of hematology. Plasma exchange (PE) was shown to nearly reverse its 90% mortality rate. However, there are still some fatal outcomes in this dramatic disease. We present our experience of plasma exchange plus corticosteroids for the treatment of TTP in our hospital. Patients with TTP diagnosed between January 1996 and January 2005 were identified by a retrospective review of records of the Uludag University Hospital, Bursa (the largest referral center for adults with this disorder in this region with an estimated 2.2 million residents), which performs all therapeutic PE in the southern Marmara region in Turkey. A total of 11 (6 male, 5 female) patients were treated for TTP during this period. The median age was 39 years (range 18-49). One plasma volume exchange daily plus steroid was the principle treatment in all patients. A total of 295 PE sessions were performed. We have obtained six complete responses (CR) and three partial responses (PR) with daily PE and steroid (response rate 9/11). One of our primary refractory patients was saved with pulse steroid+cyclosporine+vincristine. Now, he is disease free for over one year. The other refractory patient did not develop any response to salvage therapy and expired on day 15 with status epilepticus and ventilator related pneumonia (mortality rate 1/11). A CR was obtained with adjuvant treatments in all three PR patients. Only one CR patient developed an early relapse (early relapse rate in CR patients 1/6). She was treated successfully with daily PE plus vincristine. Our median follow up period was 25 months (range 9-108). Considering our local population, our annual incidence is only about 0.63 new cases per one million people. This figure is considerably less than the data from US, which indicated an incidence of 3.7 cases per 1,000,000. To our knowledge, there is no high variability in the incidence of TTP in the different geographical regions of the world. It suggests that considerable number of patients escaped notice. We hope that, demonstrating the successful outcome, this article serves to urge primary physicians to keep in mind the diagnosis of TTP and refer suspected cases quickly.

Therapeutic plasma exchange for the treatment of thrombotic thrombocytopenic purpura: a retrospective multicenter study

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a rare disease that is fatal if it is not treated. Therapeutic plasma exchange (TPE) has resulted in excellent remission and survival rates in TTP patients.

MATERIAL AND METHODS

We describe our experience with 52 TTP patients treated with TPE during the past eight years (65% of the patients were females; patient median age=34 years, range: 17-73). TPE was carried out 1-1.5 times plasma volume. Fresh frozen plasma (FFP) or cryosupernatant plasma (CSP) was used as the replacement fluid. TPE was performed daily until normalization of serum LDH and recovery of the platelet count to >150 x 10(9)/dL; TPE was then slowly tapered. Clinical, laboratory data, the number of TPE, other given therapy modalities, treatment outcomes and survival rate were evaluated retrospectively.

RESULTS

Overall response (OR) and complete response (CR) rates were 77% and 60%, respectively. Response was excellent in 82.8% of the patients with primary TTP among whom 74.2% were CR. Additionally, there were statistical differences in terms of CR rate between patients with primary TTP and secondary TTP (74.2% vs. 29.4%; p=0.005). OR and CR rates were 79% and 57.9% in patients on TPE alone and 75.8% and 60.6% in patients on TPE+prednisolone, respectively (p=1 and p=0.8). Additionally, there were no statistical differences in terms of OR and CR rates between patients on TPE with FFP and CSP (p=0.25 and p=0.16, respectively). The presence of fever and the number of TPE were statistically important factors influencing the probability of response in multivariate logistic regression analysis (p<0.01 and p<0.01, respectively). Additionally, in multivariate Cox's regression analysis, the probability of survival was higher in patients who were responsive to treatment compared to patients who were unresponsive (p<0.001).

CONCLUSION

TPE is an effective treatment for primary TTP; however, it may be used as adjunctive therapy for secondary TTP until it is under control. The addition of steroids to TPE had no advantage compared to TPE alone. CSP as replacement fluid is not superior compared to FFP. Fever appears to be a bad prognostic indicator. Therefore, prolonged treatment with TPE may be needed in patients with fever.

Predictors of response and relapse in a cohort of adults with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: a single-institution experience

BACKGROUND

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is a diagnosis of exclusion when a patient presents with the sine qua non findings of thrombocytopenia and microangiopathic hemolytic anemia without an identifiable cause. Although most patients respond to therapeutic plasma exchange (TPE), a significant number of patients relapse. The aim was to determine if clinical, laboratory, and/or treatment features could predict response and/or relapse.

STUDY DESIGN AND METHODS

This study was a retrospective review of adults with TTP-HUS treated with TPE at our institution from January 1996 to February 2004.

RESULTS

The study population consisted of 90 patients (69% female) with mean age of 45 years and mostly obese (65%). The majority of cases were considered idiopathic. Ten patients died (11%) from the disease before achieving a response, whereas 79 percent were considered responders. Obesity and severe anemia at presentation were predictors of response to TPE (p = 0.0126 and p = 0.0071, respectively). Among the responders, 28 percent relapsed in a median of 14 months. Male sex, severe thrombocytopenia (mean +/- SD, 13 x 10(9) +/- 8 x 10(9)/L), and higher lactate dehydrogenase pre-/posttreatment ratio were associated with relapse (p values of 0.0141, 0.0199, and 0.0407, respectively). ADAMTS-13 values were not obtained on enough number of patients to provide important data.

CONCLUSION

Although patient and laboratory characteristics associated with response and relapse were identified, there was significant overlap between patient groups. Thus, our findings offer preliminary evidence and do not yet justify short- or long-term changes in the management of patients with TTP-HUS.

Time course of organ dysfunction in thrombotic microangiopathy patients receiving either plasma perfusion or plasma exchange

INTRODUCTION

Few studies have investigated adults with thrombotic microangiopathy (TMA) requiring intensive care unit (ICU) admission, and the treatment remains controversial.

OBJECTIVE

To describe causes, outcomes, prognostic factors, and daily organ-failure score changes in adults with TMA requiring ICU admission.

DESIGN

A 3-yr single-center cohort study.

PATIENTS

The patients were 36 adults with TMA admitted to a teaching-hospital medical ICU between January 2000 and June 2003.

RESULTS

Of the 36 patients, 22 received plasma infusion and 15 underwent plasma exchange. All patients had anemia and thrombocytopenia at ICU admission, and 13 had neurologic impairment. Median creatinine clearance was 55.2 mL/min (interquartile range, 28.8-75.4). No patient had congenital TMA. Causative factors included microbiologically documented infection in 14 patients, allogeneic transplantation in 7 patients, and concomitant or subsequent systemic disease in 7 patients; 6 patients were human immunodeficiency virus-positive, 5 had drug-induced TMA, 2 were pregnant, and 2 had cancer. In 10 patients, no causative factors were identified. Plasma exchange was associated with a statistically significant decrease in hospital mortality (0 vs. 7 deaths; p < .001). Moreover, daily organ-failure scores were significantly lower in the plasma-exchange group from day 3 to day 9. Patients in the plasma-exchange group received a larger volume of plasma.

CONCLUSION

Plasma exchange may be associated with faster resolution of organ failure and with improved survival for patients with TMA requiring ICU admission.

Les microangiopathies thrombotiques en réanimation

OBJECTIVES

To analyze the clinico-biological manifestations, identify the causes and evaluate the outcome of patients with severe thrombotic microangiopathies admitted in a Tunisian intensive care unit.

METHODS

Retrospective study over a period of 10 years (1995-2004) in an intensive care unit.

RESULTS

Were included in this study 9 cases with a mean age of 29.2+/-9 years (range 15-44 years). Fever was observed in 5 patients, neurological impairment in 5 and digestive manifestations in 6. Haemolytic anaemia, thrombocytopenia and acute renal failure were observed in 100% of the cases. In our study, the aetiologies of thrombotic microangiopathies were: complicated pregnancy in 6 cases, systemic lupus erythematosus in 1 case. In contrast, no aetiology was found in 2 patients. Plasma exchange was performed in 5 patients, while 4 patients received only plasma infusion. After an average stay of 18+/-12.5 days, evolution was marked by the death 3 patients.

CONCLUSION

The incidence of severe thrombotic microangiopathies is rare in Tunisian ICU. The clinical manifestations are not specific. Despite the improvement in the outcome by exogenous plasma supply, thrombotic microangiopathies with severe organ dysfunctions leading to hospitalization in the intensive care unit are associated with a high mortality rate.

Acute myocardial infarction in thrombotic microangiopathies—clinical characteristics, risk factors and outcome

BACKGROUND

Acute myocardial infarction (AMI) has been reported and is associated with poor outcome in the course of thrombotic microangiopathies (TMA). However, data are very limited in regard to the clinical characteristics, risk factors and outcome of AMI during TMA. Furthermore, current AMI definitions based on troponins are more sensitive and specific to detect myocardial injury.

METHODS

We retrospectively analysed 74 consecutive patients with 78 TMA episodes. TMA was defined as platelets below 150 x 10(9)/l, haemolytic anaemia, elevated lactate dehydrogenase (LDH) and increased red cell fragmentation, and AMI as serum troponin I above 1 ng/ml with symptoms of myocardial ischaemia and/or appropriate electrocardiography (ECG) alterations.

RESULTS

AMI occurred in 14 TMA episodes (18%) (9 non- and 5 ST-segment elevation AMI). AMI occurred 5+/-3 days after TMA diagnosis, predominately in clinically suspected thrombotic thrombocytopenic purpura (TTP) as TMA subtype. Independent risk factors for subsequent AMI were TTP (RR 2.2; 95% CI 1.1-5.6), and serum LDH above 1,000 U/l (RR 2.7; 95% CI 1.3-7.2) as well as serum troponin I above 0.20 ng/ml at TMA presentation (RR 13.5; 95% CI 2.6-86.8). LDH above 1,000 U/l together with troponin I above 0.20 ng/ml had a sensitivity of 86% (95% CI 60-96%) and a specificity of 95% (95% CI 86-98%) to predict AMI in the later course of TMA. AMI contributed substantially to morbidity causing left ventricular dysfunction in three of eight survivors and potentially accounted for the death in five of six non-survivors.

CONCLUSIONS

AMI is an early, frequent and severe complication during TMA. AMI occurs especially in TTP, and serum LDH above 1,000 U/l in combination with serum troponin I above 0.20 ng/ml at TMA presentation are excellent predictors of subsequent AMI.

Thrombotic Microangiopathy Syndrome in the ICU

Major studies designed to improve our understanding of the pathophysiology of TMA have been conducted over recent years. This improved knowledge opens up new perspectives for more targeted treatment. However, until these innovative treatments become available, early diagnosis of these diseases is essential in order to rapidly initiate specific treatment, as the interval between diagnosis and initiation of plasma exchange is a decisive element in the prognosis of TTP. Treatment must not be stopped too early or too rapidly and must take into account the various associated factors, especially the presence of infection.