Assessing maternal clotting function with novel global coagulation assays: A prospective pilot study

Abstract

Introduction Women are at higher risk of venous thromboembolism (VTE) during pregnancy and the puerperium. Global coagulation assays (GCAs), including thromboelastography (TEG), thrombin generation using the calibrated automated thrombogram (CAT) and fibrin generation using the overall haemostatic potential assay (OHP), provide a more comprehensive assessment of the coagulation process than conventional coagulation assays. We aimed to evaluate the ability of these GCAs to analyse the coagulability among pregnant women of varying VTE risk profile. Methods Women undergoing term elective caesarean delivery provided a single predelivery blood sample for conventional and novel coagulation testing (TEG, CAT and OHP). Data from 47 healthy nonpregnant women aged 18‐45 years were used as controls. Results Sixty women with term singleton pregnancies were included. Samples from pregnant women were hypercoagulable on most GCA parameters compared to nonpregnant controls, demonstrating increased maximum amplitude (clot strength) (71.5 vs 60.6 mm, P < .001) on whole blood TEG and increased endogenous thrombin potential (1895.22 vs 1399.33 nmol/L·min, P < .001) and overall coagulation potential (fibrin generation) (57.58 vs 36.21 units, P < .001) on platelet‐poor plasma. Pregnant women with booking BMI ≥ 30 kg/m2 had significantly higher maximum amplitude compared to pregnant women of normal BMI (18.5‐25 kg/m2) (73.2 vs 66.1 mm, P < .001). Conclusions Global coagulation assays reliably detect the physiological hypercoagulability of pregnancy. Thromboelastography in particular appears to correlate with obesity in the pregnant population. GCAs may be potential adjuncts to risk factor‐based criteria to guide VTE thromboprophylaxis during pregnancy and the puerperium.

Risk stratification for pregnancy-associated venous thromboembolism: Potential role for global coagulation assays

“…In studies which have included postpartum measurements, it has been determined that hypercoagulability persists until at least 24 h postpartum. 50,55 Our recent study also demonstrated marked hypercoagulability in term pregnant women, 56 in particular increased alpha angle (rate of clot formation) (65.8 vs 54.1 , p < 0.001) and maximum amplitude (clot strength) (71.5 vs 60.6 mm, p < 0.001), consistent with published data. 14,[49][50][51][52][53] ROTEM has also demonstrated the hypercoagulability of pregnancy at term in several studies.…”

“…66 Multiple studies with CAT demonstrate hypercoagulability in pregnancy, including a significant increase in peak thrombin generation and ETP early in pregnancy, [67][68][69][70][71][72] consistent with our recent publication. 56 We reported that term pregnant women demonstrated markedly increased ETP (1895.2 vs 1399.4 nM/min, p < 0.001), thrombin peak (320.9 vs 240.0 nM) and velocity index (110.7 vs 83.4 nM/min, p < 0.001). Joly et al reported that thrombin generation appears to increase early on in pregnancy and remained stable during pregnancy 67 although this differed to the findings by McLean et al who reported the increase of thrombin generation with pregnancy progression.…”

“…Multiple studies with CAT demonstrate hypercoagulability in pregnancy, including a significant increase in peak thrombin generation and ETP early in pregnancy, 67–72 consistent with our recent publication. 56 We reported that term pregnant women demonstrated markedly increased ETP (1895.2 vs 1399.4 nM/min, p < 0.001), thrombin peak (320.9 vs 240.0 nM) and velocity index (110.7 vs 83.4 nM/min, p < 0.001). Joly et al.…”

“…73 We recently reported the trend of OHP in term pregnancy in 60 women -compared to healthy controls, pregnant women had significant higher fibrin generation as measured with overall coagulation potential (57.6 vs 36.2 units, p < 0.001) and overall haemostatic potential (13.4 vs 6.7 units, p < 0.001) with reduced overall fibrinolytic potential; (76.3 vs 82.1%, p < 0.001). 56 Goldenberg et al also demonstrated hypercoagulability in pregnant women using their assay, CloFAL (clot formation and fibrinolysis), which also utilised turbidimetric assay. 74 In addition, a study of 88 non-pregnant women who had experienced a prior pregnancy-related DVT revealed increased OHP levels compared with controls.…”

Viscoelastic haemostatic point‐of‐care assays in the management of postpartum haemorrhage: a narrative review

“…Altered haemostasis is common in obstetric patients as pregnancy is associated with increases in coagulation factors and changes in pro-and anti-fibrinolytic factors [1][2][3]. Haemostatic assessment is vital for identifying and correcting major haemostatic abnormalities that can contribute to events such as postpartum haemorrhage (PPH) [4]. The timely identification of coagulopathy is paramount as obstetric haemorrhage is the leading cause of maternal mortality, accounting for 27% of the 295,000 maternal deaths reported worldwide [5].…”