Longitudinal changes in vascular function parameters in pregnant women with chronic hypertension and association with adverse outcome: a cohort study

Objectives Raised vascular function measures are associated with adverse maternal and perinatal outcomes in low‐risk pregnancy. This study aimed to evaluate the association between longitudinal vascular function parameters and adverse outcome in pregnant women with chronic hypertension, and to assess whether these measures vary according to baseline parameters such as black ethnicity. Methods This was a nested cohort study of women with chronic hypertension and a singleton pregnancy recruited to the PANDA (Pregnancy And chronic hypertension: NifeDipine vs lAbetalol as antihypertensive treatment) study at one of three UK maternity units. Women had serial pulse‐wave analyses performed using the Arteriograph®, while in a sitting position, from 12 weeks' gestation onwards. Statistical analysis was performed using random‐effects logistic regression models. Longitudinal vascular parameters were compared between women who developed superimposed pre‐eclampsia (SPE) and those who did not, between women who delivered a small‐for‐gestational‐age (SGA) infant (birth weight < 10th centile) and those who delivered an infant with birth weight ≥ 10th centile and between women of black ethnicity and those of non‐black ethnicity. Results The cohort included 97 women with chronic hypertension and a singleton pregnancy, of whom 90% (n = 87) were randomized to antihypertensive treatment and 57% (n = 55) were of black ethnicity, with up to six (mean, three) longitudinal vascular function assessments. SPE was diagnosed in 18% (n = 17) of women and 30% (n = 29) of infants were SGA. In women who developed subsequent SPE, compared with those who did not, mean brachial systolic blood pressure (SBP) (148 mmHg vs 139 mmHg; P = 0.002), mean diastolic blood pressure (DBP) (87 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (139 mmHg vs 128 mmHg; P = 0.001) and mean augmentation index (AIx‐75) (29% vs 22%; P = 0.01) were significantly higher across gestation. In women who delivered a SGA infant compared to those who delivered an infant with birth weight ≥ 10th centile, mean brachial SBP (146 mmHg vs 138 mmHg; P = 0.001), mean DBP (86 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (137 mmHg vs 127 mmHg; P < 0.0001) and mean pulse‐wave velocity (9.1 m/s vs 8.5 m/s; P = 0.02) were higher across gestation. No longitudinal differences were found in vascular function parameters in women of black ethnicity compared with those of non‐black ethnicity. Conclusion There were persistent differences in vascular function parameters and brachial blood pressure throughout pregnancy in women with chronic hypertension who later developed adverse maternal or perinatal outcome. Further investigation into the possible clinical use of these findings is warranted.