Thrombotic Microangiopathies Making Sense… Thrombotic Microangiopathies ‘TTP & AHUS’ Tina Dutt Roald Dahl Haemostasis &Thrombosis Centre Royal Liverpool University Hospital

The Thrombosis –Complement Crossroads For those of you familiar with this territory you will be aware that the relationship between coagulation and complement is historic but very much a work in progress and at the best of times not always an easy map to navigate!

Complement and Coagulation Common ancestry Pro-coagulant complications Platelets Inflammation Partners in attack and defence The clot thickens.. NETosis, complement, and coagulation: a new triangular relationship De Bont et al, Nature 2018

Making sense..?

Thrombotic Microangiopathies TTP & AHUS What we knew? Rare Complex pathophysiology Significant Morbidity and Mortality Difficult to diagnose and treat well What we know? Increasing awareness of rare disease Better understanding of underlying pathology Novel Targeted therapies available Impact of Specialist care on patient outcomes

Thrombotic Microangiopathies

Microvascular thrombosis Common Endpoint Microvascular thrombosis Haemolytic anaemia Thrombocytopaenia

Untreated Untreated patients will suffer devastating consequences. The result of Thromboses in the small vessels feeding the skin and peripheries is shown here. Renal failure is a common presenting symptom. Patient will often have neurological symptoms such as mood changes, seizures or a stroke And if the heart muscle is involved these cases are often fatal

TTP Case 48 yr old female, carer, no PMHx 12pm: A&E Minors 3 day Hx of red urine, abdo pain, tired, sick, unwell 14.30: Seen by Junior doctor Plan: blood tests, antibiotics, home and refer to haematuria OPD Patient awaits antibiotic prescription in the waiting area So to start with straight in to a case which I think really shaped my thinking in this area and dare I say the direction of travel in the UK

Abnormal FBC result flagged Hb 11 (11.5-15.5) (15) 16.00 Haematology Lab: Abnormal FBC result flagged Hb 11 (11.5-15.5) (15) Platelets 10(150-450) (250) Creatinine 120 (70-100) (60) Blood film: multiple fragmented red blood cells The results are brought to the attention of the Hematology Consultant who based on the lab results strongly suspects a diagnosis of TTP

This shows a similar blood film to that which would have been found for this patient showing lots of broken red blood cells Instead of a regular and round appearance of the red blood cells there are fragments representing broken down RBCs

Referral for urgent Plasma Exchange made Haematology Consultant Review - Patient moved to RESUS for close monitoring Referral for urgent Plasma Exchange made Critical Care Outreach Team informed about patient – ‘call us if you need us’ Patient Early Warning Score 0 Within 10 minutes the Haematology team make their way to A and E where they find the patient mildly jaundiced, clutching a sick bowl awaiting her TTOs. The patient complains of tiredness, headaches and feeling worse. She is informed that it is likely that she has a very serious condition which requires urgent tx and that she will need to stay in hospital. It is suggested that a next of kin is informed of admission however the patient is reluctant as she does not wish to worry her 80 year old mother with whom she lives. The A and E sister is requested move the patient to a bed in resus and to keep the curtains open MEWS CLINIAL SCORING SYSTEM

21.00: Plasma Exchange commenced on Haematology Ward 23.00 Patient R.I.P. ADAMTS 13 < 5% Id like to now read out the account form the plasma exchange nurse who was with the patient form the time she arrived on the ward. p9

Treatment for TTP –Therapeutic Apheresis X Plasma Exchange is the only treatment that has been shown to lower the mortality of TTP and the national guidelines recommend that patients should be treated within 4-8hours of presentation. The treatment involves the patient being attached to an exchange machine as shown here and their blood volume being removed, the plasma filtered off and then the patients blood is returned with donor plasma which contains the missing ADAMTS 13 enzyme. This is an intensive process requiring secure venous access and daily exchange for at least one week daily

?TTP Door to needle time as imp as MI, acute stroke etc

TTP IS A MEDICAL EMERGENCY It is due to a deficiency of the VWF cleaving protein, ADAMTS 13, leading to spontaneous platelet aggregation in the microvasculature Suspect if LOW PLATELETS + MAHA* *MAHA = micro-angiopathic haemolytic anaemia = falling Hb with fragmentation and micro-spherocytes on blood film REFERRAL CRITERIA CLINICAL FEATURES Bruising, bleeding Neurological symptoms e.g. headache, confusion, seizures Fever History of TTP LABORATORY TESTING Platelets median 10-30 Hb median 8-10, fragmentation on film Haemolysis screen +ve retics, haptoglobins, LDH , bilirubin eGFR Clotting screen normal IF YOUR PATIENT HAS ALL OR A COMBINATION OF THE ABOVE CALL ROYAL LIVERPOOL UNIVERSITY HOSPITAL HAEMOSTASIS CONSULTANT ON CALL

AHUS Case 21 year old primip Uneventful pregnancy, NVD Unwell 1 day post partum Hb 64, Plts 23, WCC 12 Blood Film – ‘fragments’ Urea 22, Creat 411, poor urine output, SOB Diagnosis? Management? TMAs associated with pregnancy

TTP IS A MEDICAL EMERGENCY It is due to a deficiency of the VWF cleaving protein, ADAMTS 13, leading to spontaneous platelet aggregation in the microvasculature Suspect if LOW PLATELETS + MAHA* *MAHA = micro-angiopathic haemolytic anaemia = falling Hb with fragmentation and micro-spherocytes on blood film REFERRAL CRITERIA CLINICAL FEATURES Bruising, bleeding Neurological symptoms e.g. headache, confusion, seizures Fever History of TTP LABORATORY TESTING Platelets median 10-30 Hb median 8-10, fragmentation on film Haemolysis screen +ve retics, haptoglobins, LDH , bilirubin eGFR Clotting screen normal IF YOUR PATIENT HAS ALL OR A COMBINATION OF THE ABOVE CALL ROYAL LIVERPOOL UNIVERSITY HOSPITAL HAEMOSTASIS CONSULTANT ON CALL

AHUS ADAMTS 13 normal! STEC Negative Renal Impairment predominant with suboptimal response to PEX Often require haemodialysis Consider renal biopsy

Features of aHUS Familial occurrence observed Affects adult and paediatric populations Predisposing genetic mutations (vs. causative) in up to 50% cases, disease initiation factors e.g. infection, additional mutation Multi organ involvement, ~40% neuro involvement 20-30% cases present with diarrhoea High mortality ~ 50%, ~ 50% relapse, > 1/3 require long term dialysis Role of PEX unclear

aHUS Coppo and Veyradier, 2009

aHUS and Eculizumab

THROMBOCYTOPENIA and MAHA ∆∆ TTP/HUS/aHUS URGENT REFERRAL TO HAEM/ RENAL SEND ADAMTS 13 & STEC TESTS COMMENCE PEX ADAMTS 13 < 5% TTP ADAMTS 13 > 5% ? aHUS STEC +VE HUS CONTINUE PEX N.B. if ADAMTS not available pre-PEX, consider aHUS if poor response to PEX REFER FOR ECULIZUMAB SEND GENETICS CONSERVATIVE TX DISCONTINUE PEX AFTER 1ST ECULIZUMAB The specificity of severe ADAMTS13 deficiency (<5%) in distinguishing acute TTP from HUS is 90% (Bianchi et al, 2002; Zheng et al, 2004)

Making sense..?

Scully and Goodship, BJH 2014 Specialist TTP Centres When a diagnosis of an acute TMA has been made, suggesting TTP or aHUS, it is imperative that patients are transferred to Specialist Centres for treatment as soon as possible. Scully and Goodship, BJH 2014 Implementing a network of Specialist TTP Centres should drive a higher quality patient service where continuous improvement will be fuelled by volume and experience. Dutt and Scully BJH, 2015

TTP Specialist Centres NHSE HSS Commissioning by 2019 Blue Light Transfer agreement – NWAS now national 4-8 hour ‘door to needle’ – time to PEX 24/7 PEX provision Specialist led care, critical care input Trust board approved formalised care pathways ADAMTS 13 assay provision and use for monitoring National AHUS Service, Newcastle NHSE Approved Eculuzimab Genetic couselling Patient Support National AHUS Service

Rare but Reversible..

Thank you for your attention

The ‘clot’ thickens… NETosis, complement, and coagulation: a new triangular relationship Activated complement proteins can stimulate NET formation, and NETs, in turn, can serve as a platform for complement activation. NETs can act as a scaffold for thrombus formation during coagulation. NETosis appears to be a third important player in the coagulation complement cross talk consortium to protecting host against pathogen effects De Bont et al, Nature 2018 NETosis is a regulated form of neutrophil cell death that contributes to the host defense against pathogens and was linked to various diseases soon after its first description in 2004. During NETosis, neutrophils release neutrophil extracellular traps (NETs), which can capture and kill bacteria and other pathogens to prevent them from spreading. Although substantial progress has been made in our understanding of NETosis, the precise mechanism underlying NETosis is still a matter of debate. Research continues to elucidate the molecular pathways involved in NETosis. In recent years, interactions with the complement and coagulation systems have become increasingly apparent. Activated complement proteins can stimulate NET formation, and NETs, in turn, can serve as a platform forcomplement activation. In addition, NETs can act as a scaffold for thrombus formation during coagulation. While crosstalk between thecoagulation and complement systems has been previously described, NETosis appears to be a third important player in this consortium to protect the host against pathogens. This review summarizes our current knowledge on the mutual interactions between NETosis, the complement system and the coagulation system, with an emerging description of their complex triangular relationship.