Factors Associated With Acute Response To Treatment Of Severe Hypertension In Pregnancy

Pulse pressure (systolic – diastolic blood pressure; PP) has been proposed to guide medication choice for treatment of severe hypertension (HTN), as it may indicate whether the HTN is mediated by cardiac output (high PP) or systemic vascular resistance (low PP). We aimed to identify factors associated with response to treatment during pregnancy that may aid in tailoring therapy. This is a retrospective cohort study of women with severe HTN who were initially treated with intravenous labetalol, hydralazine or oral nifedipine at a tertiary care center (2015-2018). Severe HTN was defined as systolic blood pressure (BP) ≥ 160 mmHg and/or diastolic BP ≥ 110 mmHg sustained for 15 minutes or more. Association between medication choice and demographic characteristics at the time of treatment was evaluated using Pearson’s chi-square and ANOVA, where appropriate. Those with P < .2 were considered for incorporation into a multivariable model to predict resolution of severe HTN within 60 minutes of treatment. We identified 435 women who received treatment for severe HTN and grouped by initial medication received: 194 received labetalol, 137 nifedipine, and 104 hydralazine. Baseline BPs were similar among groups, but women receiving nifedipine had lower post-treatment BP and required less doses (Table 1). In the multivariable model, independent factors negatively correlated with resolution of severe HTN within 60 minutes included mean arterial pressure ≥ 125 mmHg, ≥ 2 doses administered, labetalol as first agent, PP > 75, gestational age < 37 weeks, postpartum treatment, and magnesium sulfate infusion > 10 minutes prior to resolution of severe HTN (Figure 1). The model had an optimism-corrected bootstrapped (1000 replicates) area under the curve of 0.84 (95% CI 0.76-0.86). Labetalol was associated with a longer time to resolution of severe HTN irrespective of PP. Nifedipine was associated with lower post-treatment BP and fewer required doses. Pulse pressure was not predictive of response to antihypertensives in our cohort.View Large Image Figure ViewerDownload Hi-res image Download (PPT)