(328) Individual predictors of platelet response to aspirin therapy in pregnancy

Thursday, February 9, 2023

10:30 AM – 12:00 PM

Objective: Aspirin (81mg daily) reduces the risk of preeclampsia in high-risk individuals, however, up to 30% of treated high-risk individuals still develop preeclampsia. Aspirin response in non-pregnant adults can vary widely. The objective of this study is to identify individual factors predictive of response to aspirin therapy in pregnancy. PFA-100 closure time is a measure of platelet response to epinephrine and is a quantitative measure of aspirin induced platelet inhibition.

Study Design: We conducted a prospective cohort study at Thomas Jefferson University Hospital of 130 patients with a singleton pregnancy at risk for preeclampsia and recommended aspirin therapy, 81mg daily initiated <16 weeks. PFA-100 closure time was analyzed at baseline and then 2-4 weeks after aspirin initiation. The primary outcome was PFA-100 closure time at follow-up #1. Predictors were evaluated with multivariable least squares model with stepwise variable selection using R package.

Results: 114 participants completed follow-up visit #1 with complete data for all variables. Average gestational age at baseline was 12.6±1.5 and at follow-up#1 was 16.0 ±2.3 weeks’ (p < 0.001). There was a significant increase in mean PFA-100 from baseline to follow-up #1 (131±39 vs 170±61, p< 0.001). In multivariable logistic regression, obesity and pre-gestational diabetes were associated with reduced aspirin response (lower PFA-100). Those with diabetes or obesity had lower mean PFA-100 at follow up in unadjusted and adjusted analyses (Figure). In contrast, Black race was associated with increased platelet response to aspirin therapy (MD 29 (95% CI 7-51), p=0.01) (Table). Baseline PFA-100 was also positively associated with follow-up PFA-100 (Table).

Conclusion: Individuals with pre-gestational diabetes or obesity have a reduced platelet response to aspirin therapy. This is consistent with findings in non-pregnant adults. Aspirin dosing in pregnancy may need to be adjusted based on individual characteristics.

Primary & Presenting Author(s)

Rupsa C. Boelig, MD, MS
Assistant Professor
Thomas Jefferson University Hospital
Philadelphia, Pennsylvania, United States

Coauthor(s)

EF
Emily Foecke Munden, MA
Sidney Kimmel Medical College, Thomas Jefferson University
Philadlephia, Pennsylvania, United States
TZ
Tingting Zhan, PhD
Thomas Jefferson University
Philadelphia, Pennsylvania, United States
WK
Walter Kraft, MD
Sidney Kimmel Medical College, Thomas Jefferson University
Philadelphia, Pennsylvania, United States
SM
Steven McKenzie, MD
Sidney Kimmel Medical College, Thomas Jefferson University
Philadelphia, Pennsylvania, United States