The relationship between INTEM/HEPTEM coagulation time ratio and heparin plasma concentration in obstetric patients: an exploratory in vitro investigation.

PURPOSE: Unfractionated heparin continues to be one of the main agents used for thromboprophylaxis in obstetrics, which can complicate the placement of neuraxial anesthetics. In this study, we explored the relationship between a point-of-care coagulation test (thromboelastometry) and plasma heparin concentrations in vitro. METHODS: We obtained blood from consenting obstetric patients with uncomplicated pregnancies in their third trimester who were not in labour and had a specific hematocrit range. Blood was processed and analyzed. We added increasing amounts of unfractionated heparin to samples from 0 to 0.3 U·mL-1 in 0.05 U·mL-1 increments to simulate increasing doses of unfractionated heparin. We performed INTEM and HEPTEM testing in parallel with activated partial thromboplastin time (aPTT) testing. We created a model of the relationship between heparin concentration and the INTEM/HEPTEM coagulation time (IH CT) ratio using nonlinear regression. A similar model for aPTT was also created. RESULTS: Seventy-seven patients were included in the study. Only one concentration of heparin was added to blood samples of each patient. At a concentration of 0.05 U·mL-1, the IH CT ratio was less than or equal to 1.1 in 9/11 (82%) samples. Activated partial thromboplastin time was not prolonged (> 35 sec) until a concentration of 0.1 U·mL-1 heparin was added. In all samples, the IH CT ratio was prolonged at a concentration ≥ 0.2 U·mL-1 as measured by thromboelastometry; however, at no concentration of heparin was aPTT prolonged in all samples. CONCLUSION: The point-of-care IH CT ratio may be useful in identifying the presence of little to no heparin activity. Further research is needed to determine if this ratio can predict heparin activity in vivo.

RéSUMé: OBJECTIF: L'héparine non fractionnée demeure l'un des principaux agents utilisés pour la thromboprophylaxie en obstétrique, ce qui peut compliquer la mise en place d'anesthésiques neuraxiaux. Dans cette étude, nous avons exploré la relation entre un test de coagulation au chevet de la patiente (thromboélastométrie) et les concentrations plasmatiques d'héparine in vitro. MéTHODE: Nous avons obtenu du sang de patientes obstétricales consentantes ayant des grossesses non compliquées au cours de leur troisième trimestre qui n'étaient pas en travail et dont l'hématocrite était dans une plage spécifique. Le sang a été traité et analysé. Des quantités croissantes d'héparine non fractionnée ont été ajoutées à des échantillons de 0 à 0,3 U·mL−1 en incréments de 0,05 U·mL−1 pour simuler des doses croissantes d'héparine non fractionnée. Des tests INTEM et HEPTEM ont été réalisés en parallèle avec des tests de temps de thromboplastine partielle activée (aPTT). Un modèle de la relation entre la concentration d'héparine et le ratio temps de coagulation INTEM/HEPTEM (IH CT) a été créé en utilisant une régression non linéaire. Un modèle similaire pour l'aPTT a également été créé. RéSULTATS: Soixante-dix-sept patientes ont été incluses dans l'étude. Une seule concentration d'héparine a été ajoutée aux échantillons de sang de chaque patiente. À une concentration de 0,05 U·mL−1, le ratio IH CT était inférieur ou égal à 1,1 dans 9/11 échantillons (82 %). L'aPTT n'a pas été prolongé (> 35 sec) jusqu'à ce qu'une concentration d'héparine de 0,1 U·mL−1 soit ajoutée. Dans tous les échantillons, le ratio IH CT a été prolongé à une concentration ≥ 0,2 U·mL−1 telle que mesurée par thromboélastométrie; cependant, dans tous les échantillons, aucune concentration d'héparine n'a prolongé l'aPTT. CONCLUSION: Le ratio IH CT au chevet de la patiente peut être utile pour identifier la présence d'une activité d'héparine faible ou nulle. D'autres recherches sont nécessaires pour déterminer si ce ratio peut prédire l'activité héparinique in vivo.

Managing anticoagulation in pregnancy for the anaesthetist on the labour ward.

Pregnancy is a hypercoaguable state. As part of the multidisciplinary team on labour ward, the anaesthetist plays a role particularly in advising the women and the obstetric team regarding the timing and even choice of regional analgesia given the potential risk of complications, as this may be affected by the anticoagulation treatment pregnant women may be on. It is important to understand the type of anticoagulation regimens parturients might be on and what sort of risk assessment they must undergo, as this has obstetric and anaesthetic implications. Although a rare presentation, management of women with mechanical prosthetic heart valves who are pregnant requires detailed and highly specialised care in tertiary care centres with a well-developed multidisciplinary team and pathway. Despite their rare presentation, it is important to understand the intricate and complex management that these women require as they have a high morbidity and mortality rate.

Pregnancy in women with cardiac disease: a one-year retrospective review of management and maternal and neonatal outcomes in a tertiary hospital in Johannesburg, South Africa.

INTRODUCTION: In South Africa, cardiac disease continues to be the most important non-obstetric cause of maternal death. METHODS: A record review of 74 pregnant women with cardiac disease was performed to determine the prevalence and outcomes of cardiac disease at Charlotte Maxeke Johannesburg Academic Hospital between January and December 2017. RESULTS: Rheumatic heart disease was the most common cardiac diagnosis (n = 21, 28.4%), followed by pulmonary hypertension (n = 13, 17.6%) and congenital heart disease (n = 12, 16.2%). There were one (1.4%) maternal and two (2.7%) perinatal deaths. Neonatal complications included pre-term delivery (n = 20, 32.3%) and small-for-gestational-age infants (n = 10, 16.1%). Cardiac complications (n = 30, 40.5%) included heart failure (n = 15, 20.3%), pulmonary hypertension (n = 11, 14.9%) and blood transfusions (n = 8, 10.8%). CONCLUSIONS: Cardiac disease in pregnancy was associated with a high risk of maternal and neonatal complications. Pre-conceptual counselling and managing pregnant women at a dedicated centre by a multidisciplinary team could, however, improve outcomes.

Complicated Cerebral Venous Thrombosis During the First Trimester of Pregnancy.

Pregnancy and puerperium are known conditions associated with venous thrombotic events, which may present atypically in cases such as cerebral venous thrombosis. Since these are uncommon events, there is a paucity of reports and protocols for the management of these patients, resulting in no clear consensus in the literature. We report a case of a woman, nine weeks pregnant, who developed thrombosis of the right transverse and superior sagittal sinuses. Our diagnosis was made with computed tomography angiography, and due to a significant midline shift, an emergency decompressive hemicraniectomy was required. Although medical and surgical therapies for intracranial hypertension and anticoagulation were optimized in accordance with current medical literature, the patient suffered a spontaneous abortion and remained with significant neurological sequelae.

Management of high risk cardiac conditions in pregnancy: Anticoagulation, severe stenotic valvular disease and cardiomyopathy.

Cardiovascular disease contributes to approximately one third of all maternal mortality and remains a significant source of peri­ and postpartum morbidity. As more women at risk for and with cardiovascular disease are desiring pregnancy, it is imperative that general cardiologists and obstetricians participate collaboratively in preconception counseling and are more facile with management of these lesions during peri­ and postpartum periods. This review aims to address this growing need and highlights the management strategies for some of the major high risk cardiac conditions encountered during pregnancy including anticoagulation, cardiomyopathies as well as severe mitral and aortic stenosis; aortopathy, pulmonary hypertension, and severe congenital heart lesions will not be addressed.