///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Factors Related to Abnormal Coagulation Testing in Preeclampsia

Abstract Number: T2I-168
Abstract Type: Original Research

David J Combs MD, PhD1 ; Brian T Bateman MD, MSc2

Introduction: Along with thrombocytopenia, women with preeclampsia are at heightened risk for coagulopathy, potential contraindications to neuraxial procedures. There is limited evidence to inform laboratory evaluation of coagulopathy in preeclampsia and whether completing such testing should delay neuraxial techniques. Current recommendations are based on an analysis of 100 women with preeclampsia wherein abnormal coagulation testing was rare for platelet counts above 100,000/μL (Leduc L. et al, 1992).

Methods: Using a clinical registry of two academic tertiary care hospitals, we performed a cross-sectional study of abnormal coagulation testing in preeclamptic deliveries between 1995 and 2018. Patients who received anticoagulant medication in the 30 days prior to delivery were excluded. For all patients, the platelet count determined at the time of admission and coagulation parameters (measured no later than 2 hours after the platelet count) were obtained. The frequency of abnormal coagulation test results, defined as either an activated partial thromboplastin time (aPTT) or the international normalized ratio (INR) above the reference range, was compared across patients grouped by their initial platelet count.

Results: Of 2,235 deliveries with preeclampsia, 103 (4.6%) had abnormal coagulation testing. The risk of abnormal coagulation testing increased with decreasing platelet counts. For patients with an initial platelet count ≥ 150,000/μL the risk was 3.3% (95% CI: 2.5% to 4.2%), for 149,000 to 100,00 /μL was 7.1% (95% CI: 4.8% to 10.3%), for 99,000 to 70,000/μL was 6.15% (95% CI: 3.2 to 11.7%), and for less than 70,00 was 18.8% (95% CI: 11.9% to 28.4%; p = 3.0 x 10-9). When abnormal coagulation was defined as an aPTT ≥ 40 s or an INR ≥ 1.4 (potentially more clinically meaningful thresholds) the frequencies of abnormal testing across the four platelet groups were 1.3%, 4.1%, 3.1%, and 7.1%, respectively. Patterns of abnormal coagulation testing were not meaningfully different after excluding patients with antepartum hemorrhage or known congenital coagulopathy.

Conclusion: In patients with preeclampsia at delivery, the frequency of abnormal coagulation testing is higher in those with a lower initial platelet count. In such patients, anesthesiologists will need to weigh the risks and benefits of proceeding with neuraxial techniques without coagulation testing.

SOAP 2019