Cardiac Biomarkers in Pregnancies with and without Hypertension

Abstract Background Mechanisms of injury due to hypertension (HTN) in pregnancy remain poorly characterized. This study examined trends in markers of cardiac injury (high-sensitivity troponin I, hs-cTnI), strain (N-terminal pro-B-type natriuretic peptide, NT-proBNP), and inflammation (high-sensitivity C-reactive protein, hs-CRP) in pregnancies with and without HTN. Methods This prospective, 1:1 case-control study enrolled pregnant women with and without HTN (24-32 weeks gestation) from 2019-2022. HTN was defined by a clinical diagnosis of HTN or baseline blood pressure (BP)≥140/90 mmHg. Serum was collected at baseline, pre-delivery, and postpartum day 1. Mixed effects tobit models compared log-transformed hs-cTnI, NT-proBNP, and hs-CRP across HTN groups and over time, adjusted for age and BMI. Results Mean baseline BP was 130.5 (17.5)/88.2 (13.5) mmHg for the HTN group (n=38, 86.8% chronic, 13.2% gestational HTN), and 112.0 (9.8)/70.9 (8.2) mmHg for those without HTN (n=38). Over pregnancy, the HTN group had higher hs-cTnI than those without HTN (2.12 [0.43] vs. 1.07 [0.25], Δ1.05 [95%CI: 0.07-2.03] ng/L). Compared to baseline, hs-cTnI increased at pre-delivery and postpartum for both groups. Overall, the two groups had similar NT-proBNP (HTN: 39.0 [4.5] vs. no HTN: 35.6 [4.3] pg/mL) and hs-CRP (HTN: 12.0 [1.7] vs. no HTN: 9.9 [1.5] mg/L). For both groups, NT-proBNP and hs-CRP increased from baseline to postpartum (NT-proBNP, HTN: 127% [58-227%], no HTN: 120% [51-219%]; hs-CRP: HTN: 550% [343-853%], no HTN: 664% [415-1034%]). Conclusion HTN was associated with markers of cardiac injury during pregnancy, while delivery alone led to increases in markers of strain and inflammation. These biomarker changes associated with HTN in pregnancy may represent potential mechanisms to explain adverse cardiovascular events.