Rotational thromboelastometry (ROTEMÒ) in Pre-eclampsia – a Pilot Study
P Squires1, G Crossingham1, D Thorp-Jones2, P Moor2, R Roberts3, S Welchmann4
1Anaesthetic Registrar, Derriford Hospital, Plymouth, 2 Consultant Anaesthetist, Derriford Hospital, Plymouth
3 Consultant Obstetrician, Derriford Hospital, Plymouth, 4 Registrar Colorectal Surgery, Derriford Hospital, Plymouth
Introduction: Coagulopathy associated with pre-eclampsia (PET) can increase the risk of peri-partum haemorrhage and have implications for anaesthesia, yet standard coagulation tests are relatively slow and limited.1 Rotational thromboelastometry (ROTEMâ) examines real-time whole-blood clotting and could potentially provide faster, more accurate results allowing more rapid, targeted management.1
Peri-partum ROTEMâ studies consistently demonstrate the hypercoagulable state of pregnancy. 2 However there has been very little research into the use of ROTEMâ in PET. We therefore aim to increase understanding of PET-associated coagulopathy using ROTEMâ, and assess the feasibility of a larger study of routine ROTEMâ use in PET.
Methods:Ethics approval and local funding for a 9-month recruitment period aiming to recruit 50 patients with PET was obtained. Patients in established labour, with a known thombophilia or coagulopathy, or within 12 or 24 hours of a dose of prophylactic or treatment dose enoxaparin respectively, were excluded.
Patients consented for a single blood test to run a full ROTEMâ coagulation profile using INTEM, EXTEM and FIBTEM reagents. Routine platelet count and clotting screen results were also recorded. Data was collected on patient demographic, antenatal aspirin and enoxaparin use, PET severity and treatment, and ROTEMâ testing issues. All maternity theatre staff were trained to use the ROTEMâ machine.
Results:17 patients have been recruited to date and we have complete ROTEMâ data for 14 patients (age range: 20-48 years, median 29.5 years; gestation range 26+6 - 39+4). 3 patients were on aspirin and 3 were on enoxaparin. No patients had HELLP syndrome. All patients had a platelet count of >100 x 109/L and normal INRs.
Using standard reference ranges3, 6 patients had increased clotting activity evident on INTEM and 7 had increased activity on EXTEM. 1 patient had decreased activity on both tests. The majority of patients (8/14) had increased clotting activity on FIBTEM testing.
This is compared to using proposed peri-partum reference ranges2, where only 2 patients had increased activity on INTEM and EXTEM tests. On FIBTEM tests 4 patients had increased clotting activity using these ranges, whilst 1 patient showed reduced activity.
Discussion: Recruitment to the study has been challenging due to lower numbers of PET patients than predicted and initial ROTEMâ machine issues. Early findings demonstrate that many of the PET patients have increased clotting activity on ROTEMâ testing to some degree; consistent with the hypercoagulability seen in ROTEMâ studies in healthy parturients. Possible explanations for this include: a true hypercoagulable state, non-severe PET with no coagulopathy, or perhaps inability of ROTEMâ to detect mild PET-associated coagulopathy. Potentially, PET-associated coagulopathy is only detected by ROTEMâ in those with very severe PET and/or HELLP syndrome.
FIBTEM testing revealed increased clotting activity, even when using proposed peripartum ranges in some patients. This may indicate hyperfibrinogenaemia in these patients or in pregnant patients in general.
One patient had reduced activity in INTEM/EXTEM tests using both sets of reference ranges evidenced by a low MCF despite a normal platelet count. This could indicate abnormal platelet function. If HELLP syndrome or abnormal platelet function is the main cause of severe coagulopathy in PET then investigation of platelet function itself using modern platelet-mapping techniques may be the key to identifying coagulopathy and guiding treatment in these patients. In order to draw firm conclusions, further research with greater sample numbers is needed in the use of ROTEMâ in PET.
1. C.Solomon, R.E.Collis and P.W.Collins. ‘Haemostatic monitoring during postpartum haemorrhage and implications for management’. BJA 2012, 109 (6): p851-63.
2. N M De Lange et al. ‘Peri-partum reference ranges for ROTEMâ thromboelastometry’. BJA 2014, 112 (5) p852-9.
3. Lang et al. 'Multi-centre investigation on reference ranges for ROTEMâ thromboelastometry' Blood Coagul Fibrinolysis. 2005 Jun; 16(4):301-10