Anno: 2012 Lavoro: Mese: December titolo breve: COAGULATION ASSESSMENT IN NORMAL PREGNANCY Volume: 78 primo autore: DELLA ROCCA No: 12 pagine: 1357-64 Rivista: MINERVA ANESTESIOLOGICA Cod Rivista: Minerva Anestesiol © , COPYRIGHT 2012 EDIZIONI MINERVA MEDICA ORIGINAL ARTICLE Coagulation assessment in normal pregnancy: thrombelastography with citrated non activated samples G. DELLA ROCCA 1, T. DOGARESCHI 1, T. CECCONET 1, S. BUTTERA 1, A. SPASIANO 1, P. NADBATH 1, M. ANGELINI 2, C. GALLUZZO 2, D. MARCHESONI 2 1Department of Anesthesia and Intensive Care Medicine, University of Udine, Udine, Italy; 2Department of Obstetrics and Gynecology, University of Udine, Udine, Italy ABSTRACT Backgound. Thrombelastography (TEG) provides an effective and convenient means of whole blood coagulation monitoring. TEG evaluates the elastic properties of whole blood and provides a global assessment of hemostatic function. Previous studies performed TEG on native blood sample, but no data are available with citrated samples in healthy pregnant women at term. The aim of this study was to investigate the effect of pregnancy on coagula- tion assessed by TEG and establish normal ranges of TEG values in pregnant women at term comparing them with healthy non pregnant young women. Methods. We enrolled pregnant women at term undergoing elective cesarean section or labour induction (PREG group) and healthy non-pregnant women (CTRL group). Women with fever or inflammatory syndrome, defined as C-reactive protein (CRP) >5 mg/L and with a platelet count <150.000/mm3 have been excluded. For each women hemochrome and standard coagulation test were assessed. At the same time we performed a thrombelastographic test with Hemoscope TEG® after sample recalcification without using any activator. Results. One hundred thirty patients were studied, 65 for each group. There were no differences between groups regarding demographic data. Hemoglobin, platelet count, International Normalized Ratio and Activated Partial Thromboplastin Time Ratio were lower and fibrinogen was higher in PREG group. All TEG parameters resulted as being significantly different between the groups with a hypercoagulable pattern in PREG group compared to CTRL group. Conclusion The main findings of this study confirm the hypercoagulability status of pregnant women at term. This coagulation pattern is well represented by thrombelastographic trace obtained by recalcified citrate blood sample. (Minerva Anestesiol 2012;78:1357-64) Key words: Thrombelastography - Pregnancy - Blood coagulation. regnancy is associated with changes in he- To assess the perioperative coagulation status Pmostasis, including increases in the levels of a patient, routine coagulation tests (e.g., plate- of most clotting factors, a decrease in antico- let count, prothrombin time, activated partial agulants, and a reduction in fibrinolytic activity. thromboplastin time, and fibrinogen) are still These changes result in a state of hypercoagula- widely used despite their limitations.3, 4 They do bility that minimizes the risk of hemorrhage dur- not provide any information on the kinetics of ing pregnancy and immediately after delivery.1, 2 clot formation, on clot strength, on the inter- actions between the coagulation components, Comment in p. 1319. on platelet function, or about fibrinolysis; fur- This document is protected by international laws.This document is protected by copyright No additional reproduction is authorized. of this Article. only one file and print only one copy and save use to download personal It is permitted for It is not permitted additional copies to make either printed purpose. or electronic) of the Article any for or systematically, (either sporadically of the article It is not permitted the electronic copy to distribute through online internetother file sharingelectronic mailing or any and/or intranet systems, access to the Article. allow means which may part The use of all or any Commercial Use is not permitted. of the Article any for works from the Article The creation of derivative is not permitted. personal or commercial use is The production of reprints for post on the Article. notices or terms may copyright of use which the Publisher or change any block, obscure, not permitted. trademark, overlay, logo It is not permitted techniques to enclose any or use framing to frame cover, It is not permitted to remove, or other proprietary of the Publisher. information Vol. 78 - No. 12 MINERVA ANESTESIOLOGICA 1357 © , COPYRIGHT 2012 EDIZIONI MINERVA MEDICA DELLA ROCCA COAGULATION ASSESSMENT IN NORMAL PREGNANCY thermore, the generation of results is slow.3, 4 To Exclusion criteria were: a history of chronic or overcome these limitations, there is a need for a obstetric disease, coagulation disorders, or post- specific, sensitive, and rapid bedside test for mon- partum hemorrhage; the consumption of estro- itoring coagulation. Thrombelastography (TEG) progestinics, antiplatelet or anticoagulant drugs; allows for a qualitative and dynamic analysis of the presence of fever or inflammatory syndrome the specific blood clotting process, from clot for- (defined as C-reactive protein [CRP]>5 mg/L); mation through its lysis, highlighting alterations or a platelet count <150x103/mm3. at every single step in the cascade.5 It studies the viscoelastic properties of a blood sample and Study protocol their changes during coagulation process, repro- ducing them in a graphical trace and measuring Following hospital admission, venous blood defined parameters well explained by Di Bene- was collected through a single 18 gauge can- detto.5 Camezind et al. studied TEG using fresh nula placed in a peripheral vein. Routine blood native blood, but, if samples cannot be processed tests were performed: hemoglobin concentration in few minutes, they can be citrated and then (Hb), hematocrit (Hct), platelet count (PLT), assessed at a later time following recalcification6 activated partial thromboplastin time ratio as Armstrong and collagues did with ROTEM®.7 (aPPTr), international normalized ratio (INR), No data are available regarding TEG for the as- and fibrinogen (FBN); all samples were analyzed sessment of citrated blood samples from preg- in one central laboratory. Through the same 18 nant women; furthermore, the reference values gauge cannula, a consecutive blood sample was supplied by manufacturers of TEG machines are collected into a 4.5 mL tube (BD Vacutainer wide, and they cannot be applied to pregnant System, Belliver Industrial Estate, UK) contain- women. ing a 3.8% sodium citrate solution (0.129 M). The aim of this study was to investigate the Within 1 h from the time of collection, TEG effects of pregnancy on coagulation assessed by was performed using a Hemoscope TEG 5000 TEG and establish the normal ranges of TEG Coagulation Analyzer® (Hemoscope Corp., values, including: reaction time (R, minutes), Niles, IL, USA) following the recalcification of clot formation time (k, minutes), α-angle (α, 340 µL of blood with 20 µL CaCl (0.2 M) with- degrees), maximum amplitude (MA, mm), and out activators by just two defined expert opera- clot lysis at 30 and 60 min (Ly30 and Ly60%). tors to reduce the possibility of inter-tester vari- TEG values for citrated/recalcified blood taken ability affecting the results. TEG data analyzed from pregnant women at term were compared were: reaction time (R, minutes), clot formation to those obtained from healthy young women time (k, minutes), α-angle (α, degrees), maxi- confirmed not to be pregnant. mum amplitude (MA, mm) and clot lysis at 30 and 60 min (Ly30 and Ly60, respectively; %). Materials and methods Statistical analysis Inclusion and exclusion criteria A preliminary analysis of TEG data of a pilot Following approval by the Ethics Committee study detected a 15% difference in mean R val- and informed written consent, healthy women ues between the PREG and CTRL groups; so a with single spontaneous pregnancies were en- sample size of 63 patients per group was required rolled into the study. All women were at term (α 0.05, β 0.05). (gestational age >38 weeks) and scheduled for Student-t tests were used to compare the elective cesarean delivery or induction of labor PREG and CTRL group data, except for Lys 60 (PREG group). As controls, healthy non preg- data that did not have a normal distribution, so nant women (under 40 years of age) scheduled a Mann-Withney test was performed. A value of for gynecological, maxilla-facial or orthopedic P<0.05 was considered statistically significant. surgery (CTRL group) were enrolled. Statistical analysis was conducted using Graph- This document is protected by international laws.This document is protected by copyright No additional reproduction is authorized. of this Article. only one file and print only one copy and save use to download personal It is permitted for It is not permitted additional copies to make either printed purpose. or electronic) of the Article any for or systematically, (either sporadically of the article It is not permitted the electronic copy to distribute through online internetother file sharingelectronic mailing or any and/or intranet systems, access to the Article. allow means which may part The use of all or any Commercial Use is not permitted. of the Article any for works from the Article The creation of derivative is not permitted. personal or commercial use is The production of reprints for post on the Article. notices or terms may copyright of use which the Publisher or change any block, obscure, not permitted. trademark,