Hypertensive disorders during pregnancy are associated with a 2.4 times higher risk of hypertension even in the 10 years after pregnancy, according to a new study involving predominantly Black women.
Longer-term cardiovascular (CV) risk – i.e., over 20 to 30 years – is already well-established following hypertensive disorders of pregnancy (HDP), including gestational hypertension and pre-eclampsia.
The new findings – published Monday online ahead of the June 21 issue of the Journal of the American College of Cardiology – are some of the first to demonstrate ongoing risk in the intervening decade post-HDP, particularly within a predominantly Black (85% self-identifying as Black) cohort.
“The importance of studying a more diverse population, including a larger percentage of Black patients, is of critical importance given that both HDP and [cardiovascular disease – CVD] disproportionally affect Black women,” lead author Lisa Levine, MD, MSCE, from the University of Pennsylvania, said in an accompanying press statement.
HDP impacts close to 20% of all pregnancies and is the leading cause of maternal death around the world, and carries higher long-term risk of heart disease and stroke.
A total 135 patients were enrolled into the prospective cross-sectional study from April 2016 to December 2019 from a previous observational study, conducted from 2005 to 2007, which had enrolled 439 patients with obstetrician-confirmed HDP.
Subjects were included both with (84 subjects) and without (51 subjects) a history of HDP in a pregnancy ≥10 years earlier, and who underwent in-person visits with echocardiography, arterial tonometry and flow-mediated dilation of the brachial artery. Only patients without a history of cardiac disease, chronic hypertension or pregestational diabetes at the time of enrollment into the original parent study, 10 years earlier, were included.
In the group without a history of HDP, 78.4% were Black and 21.6% white, while 91.7% of those in the group who had a history of HDP were Black vs. 8.3% white (P = 0.037).
At study visit, those with no HDP history had a median age of 39.1 years compared to 35.7 years in HDP, while those with HDP history were heavier (median body mass index [BMI] of 31.4 kg/m2 vs. 29.9 kg/m2), more likely to smoke (25% vs. 21.6% current tobacco users), and more likely to have a history of preterm birth (50% vs. 19.6%; P = 0.001).
HDP severity was most commonly marked as “severe preeclampsia (including [hemolysis, elevated liver enzymes, low platelets])” (61.9%), while 38.1% had mild gestational hypertension or preeclampsia. For 39.3%, HDP was recurrent.
Stage 2 chronic hypertension more than twice as likely following HDP
The researchers found that patients with a history of HDP had a 2.4-fold increased risk of new stage 2 chronic hypertension vs. those without HDP (56% vs. 23.5%, respectively) a relative risk of 2.38 (95% confidence interval [CI]: 1.40 – 4.40), “even when adjusting for race, maternal age, BMI, and history of preterm birth” (adjusted relative risk: 2.4; 95% CI: 1.39-4.14).
Criteria for stage 1 or 2 chronic hypertension were met in 82.1% of those with HDP history and 60.7% of those without (P < 0.001).
There was no association with other identifiable clinical CV risk factors such as diabetes, obesity or metabolic syndrome, the researchers found.
The researchers also found that there were no differences in non-invasive subclinical measures of CV risk, including left ventricular structure, global longitudinal strain, diastolic function, arterial stiffness or endothelial function.
The patients who did develop hypertension – regardless of HDP history – had greater left ventricular remodeling, including greater relative wall thickness; worse diastolic function, including lower septal and lateral e’ and E/A ratio; more abnormal longitudinal strain; and higher effective arterial elastance than those without hypertension, the researchers added.
“Differences in noninvasive measures of CV risk were driven mostly by the hypertension diagnosis, regardless of HDP history, suggesting that the known long-term risk of CVD after HDP may primarily be a consequence of hypertension development,” the researchers said.
Underdiagnosis and importance of routine screening
“Importantly, 18% of patients with a history of HDP met criteria for a new diagnosis of hypertension identified through the study visit,” the researchers added.
More than 60% of all patients who met criteria for either stage 1 or 2 hypertension did not have a formal diagnosis before the study, while among those with HDP history, just 39% of patients with either stage 1 or 2 hypertension had a formal diagnosis, “potentially missing the other half of patients in this category if screening had not otherwise been performed outside of our current study,” the researchers noted.
This, together with the effect hypertension has on future CV risk, “highlights the importance of early screening for hypertension in women post-pregnancy complicated by HDP and the importance of initiating antihypertensive treatments to decrease the long-term risk of CVD,” said the researchers.
“Future studies should evaluate the optimal time period to screen for postpartum hypertension and a monitoring plan for these at-risk women.”
In an accompanying editorial, Josephine C. Chou, MD, MS, of the Yale University School of Medicine, went on to highlight studies showing that chronic hypertension increases the risk of symptomatic heart failure in the 3 years after a preeclampsia/ eclampsia-related pregnancy, adding “even at 1 year postpartum, patients with HDP have not only a 4-fold increased risk of [chronic hypertension] but also higher 30-year CVD risk scores.”
“The initial postpartum years offer a window of opportunity to impact lifelong CV health, with ample evidence supporting [chronic hypertension] as the most important condition to target for reducing CVD in patients with HDP,” she added.
Yet, the high incidence of undiagnosed hypertension observed in the study highlights that the opportunity is “frequently missed,” said Chou.
“Only [around] 60% of patients with HDP have a continuity care visit by 6 months postpartum,” she said, potentially because of caregiving challenges faced by parents, fatigue, pain and exacerbation of mental health disorders.
“In contrast to the intensity of prenatal visits, postpartum care is relatively episodic and limited,” she lamented, but highlighted “promising strategies” incoming, such as postpartum transitional clinics providing CVD risk assessments with counseling.
Chou went on to call for further studies to evaluate new interventions, adding: “Black patients are known to be disproportionately affected by HDP and their complications. However, it is important to recognize race as a social construct, and not an inherent risk factor for disease.
“Therefore, addressing these disparities requires an understanding of the distinct CV profiles and sociodemographic factors that contribute to HDP and CVD in Black patients.”
The current study paves the way for such efforts, she said.
“[Our trial] along with studies with similar findings, further highlights the importance of routine screening for hypertension in this population,” Levine added. “Future studies should evaluate the optimal time period to screen for postpartum hypertension and a monitoring plan for these at-risk women.”
Levine LD, Ky B, Chirinos JA, et al. Prospective Evaluation of Cardiovascular Risk 10 Years After a Hypertensive Disorder of Pregnancy. J Am Coll Cardiol 2022;79:2401–2411.
Chou JC. Hypertensive Disorders of Pregnancy and Cardiovascular Risk: We Are Missing the Opportunity of a Lifetime. J Am Coll Cardiol 2022;79:2412–2414.
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