Abstract
Keywords
Gestational hypertensive disease is defined as a condition in which systolic blood pressure is ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg after the gestational age of 20 weeks in women who previously had normal blood pressure. Preeclampsia is hypertension complicated with large amounts of protein in the urine, ≥300 mg/24 h [1]. Several systematic reviews and meta-analyses have consistently stated that women with preeclampsia are at increased risk of cardiovascular and cerebro-vascular disease [2–4]. These studies show that women with early preeclampsia may develop a cardiovascular event at a relatively young age, that is, before the age of 56 years. The occurrence of hypertensive disorders in pregnancy as a serious cardiovascular disease (CVD) risk factor is further supported by studies in which the values of the classical risk factors were determined shortly after pregnancy, for example, higher levels of fasting glucose, lipids and coagulation factors [5,6]. The urgency to have a structured postpartum cardiovascular screening program for women who have experienced a hypertensive pregnancy disorder was stressed in a recent article by the Dutch gynecologists Julia Spaan et al. in Hypertension [7]. This triggered Maria Cusimano and colleagues to launch a maternal health clinic (MHC) within the setting of Kingston General Hospital in Ontario, Canada, to treat women with pregnancy-related complications, identify women with potentially increased CVD risk, encourage lifestyle changes and to ultimately ensure long-term follow-up [sic] and specialist referral [8]. They report on the results of the first 17 months of completed visits at the MHC.
Methods
The MHC started in November 2011. Women were invited for a screening examination if they had experienced gestational hypertension, preeclampsia, gestational diabetes or impaired glucose tolerance. Based on prenatal records, the number of deliveries in the eligible time period to March 2013 was 3015. Of them, 387 were booked in to the MHC. After exclusion of women who did not show up and/or had incomplete test results, there were 92 women in the MHC study population. Their findings on CVD risk were compared with outcomes of 118 women in the normotensive postpartum control group, sampled from a prospectively entered cohort, previously described [9]. Full assessment included medical history in the gynecology and obstetrics field, blood and urine testing and risk-factor determination by three prediction methods, that is, a lifetime and a 30-year CVD risk estimate together with a metabolic syndrome calculation. With this data, the authors can convert the estimates to absolute numbers of CVD events brought about by pregnancy-related complications.
Results
The average age of the patients of the MHC group and the control group was almost similar being, respectively, 32.9 and 31.5 years. The former group had a somewhat higher pre-pregnancy BMI of 26.7 kg/m2 versus 25.4 kg/m2 for the latter, which goes along with elevated postpartum BMI and waist circumference of ca. 90 cm. No differences in parity, annual household income, education and breastfeeding practice were observed.
In this study, the three CVD risk estimates were of particular interest. They appeared to be consistently higher in the MHC women. The median 30-year CVD risk was 7.5 versus 5.3% in the control group. Expressed in a different way, only 16% was predicted as having an optimal risk profile versus 54% in the control women. The prevalence of metabolic syndrome was 17 versus 7%.
Significance
Cusimano's research is interesting as it clearly demonstrates high prevalences of increased CVD risk. The average woman with pregnancy-related complications participating in the postpartum screening program showed twice as many CVD risk factors as did controls. It underpins the importance of access to facilities like the MHC and the need for future lifestyle coaching initiatives. Because this is a recent publication, there is little comparable literature to be found. But the main impression given is one of a valuable new healthcare service. Limitations of the study, however, include the artificial (self-)selection of the study population and their desire for healthy behavior (no data on physical activity were collected in the control group), small sample size and failure to adjust for confounders such as body weight.
Following the detection of elevated risk, the next issue is the timing and effectiveness of lifestyle changes by increasing physical activity levels and reducing caloric intake. For supporting evidence, the authors refer to a meta-analysis that propagates postpartum exercise interventions, particularly those combined with dietary interventions and tools like pedometers and heart rate monitors; all being beneficial in improving weight loss [10]. In this case, it is conceivable that the MHC is a little too optimistic in publishing the results of their target population. The mean weight loss appeared to be 5 pounds (2.27 kg) to 8 pounds (3.64 kg) at best, when exercise interventions were framed in clearly defined targets and monitored by objective software. In addition, the mean difference in body weight loss has to be related to actual baseline body weight and for the resulting decrease in CVD.
Conclusion
Cusimano et al. describe the urgent need for healthcare follow-up for women sustaining hypertensive episodes in pregnancies. MHC-like initiatives will effectively identify women who have elavated cardiovascular risks that prompt lifestyle modification and not to waiting for future cardiovascular disease to manifest itself.
Future perspective
Hypertension-complicated pregnancy serves as a good biomarker for future CVD and metabolic syndrome. Based on this medical knowledge combined with the ‘first-things-first’ information provided by the Canadian MHC, a series of follow-up studies are to be expected. In the meantime, American Guideline committees advise incorporating obstetric history in cardiovascular risk management. The most recent of these are the stroke guidelines for women [11]. The risk of stroke after sustaining preeclampsia increases threefold to fourfold, so the stroke guideline continues: “Because of the increased risk of future hypertension and stroke 1 to 30 years after delivery in women with a history of preeclampsia (Level of Evidence B), it is reasonable to (1) consider evaluating all women starting 6months to 1year post partum, as well as those who are past childbearing age, for a history of preeclampsia/eclampsia and document their history of preeclampsia/eclampsia as a risk factor, and (2) evaluate and treat for cardiovascular risk factors including hypertension, obesity, smoking, and dyslipidemia (Class IIa; Level of Evidence C).”
From this, it is clear that assessment should start early. But we have to bear in mind that this recommendation is only based on moderate levels of evidence.
Furthermore, no controlled study has been conducted in which the clinical effectiveness and cost–effectiveness of preventive measures are integrally examined. However, for the time being, following a slightly modified guideline could be worthwhile for women with pregnancy-related complications. They form a relatively young population who qualify for lifestyle changes, and some of them for medication according to CVD risk assessment of cigarette smoking, blood pressure, cholesterol and age. Because of their young age, most are not eligible for preventive medication, unless we reduce the current age constraints by approximately 15 years.
Executive summary
The maternal health clinic initiative targets women with increased risk of cardiovascular disease caused by hypertensive pregnancy-related conditions.
The yield from the first 17 months of completed clinic visits reveals large contingents of women requiring immediate lifestyle modification.
Before expanding the formula of launching maternal health clinics for risk identification for women with a history of preeclampsia, replication of the findings and cost-effectiveness analysis are needed to tailor follow-up schedules and lifestyle coaching.
Footnotes
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.