The Effect of Chronic Hypertension on Control of Severe Range Blood Pressures in Preeclampsia [36P]

Abstract

INTRODUCTION: We aim to assess the impact of maternal hypertension category on the control and response of urgent hypertension. METHODS: This is a retrospective cohort study of patients who required immediate-acting antihypertensive medications outlined by the ACOG Committee Opinion #692 during the peripartum admission between June 2015 to June 2017. The patients were either diagnosed with preeclampsia with severe features (“preSF”) or chronic hypertension with superimposed preeclampsia with severe features (“cHTN+preSF”). We abstracted maternal medical history and medication dosing. Statistical significance was calculated with the Student's t-test or Mann-Whitney test. Multivariable regression analysis was used to adjust for the effect of confounders. RESULTS: We identified 326 patients, 211 with preSF and 115 with cHTN+preSF. In the antepartum period, patients with cHTN+preSF received significantly more doses of immediate-acting antihypertensive medications than those with preSF (3 vs 2 doses, p<0.01). The cHTN+preSF group also required more time for blood pressures to exit severe range (55 vs 30 minutes, p<0.01) and more frequent re-dosing of anti-hypertensive medication (2 vs 1 times, p=0.02). The differences remained significant in the multivariable regression model when controlled for age, gravidity and BMI. During the postpartum period, the same parameters were similar between the groups. CONCLUSION: While chronic hypertension is recognized as a risk factor for the development of preeclampsia, we demonstrate that it also complicates and prolongs the course of blood pressure management particularly in the antepartum period. Consideration should be given to maternal history when tailoring treatment of severe hypertension in patients with pre-eclampsia.