Abnormal mid-trimester cardiac strain in women with chronic hypertension predates superimposed preeclampsia

Background: Chronic hypertension (cHTN) affects 7% of all pregnancies. We hypothesized that cHTN during pregnancy would be associated with abnormal myocardial strain patterns and adverse perinatal outcomes.

Methods: This was a retrospective cohort study of patients seen in a high-risk obstetrics clinic with cHTN. Parturients with a singleton pregnancy who had undergone an echocardiogram as part of routine clinical care were eligible. Clinical and demographic information was collected from medical records. Global peak longitudinal strain (GLS) was measured using automated software from stored echocardiographic images.

Results: 60 patients were included in this analysis, of which 48 (80.0%) were African American. The median BMI was 40.6, age was 34 years, and the gestational age was 20.4 weeks at the time of the echo and 37.9 weeks at delivery. Thirty-four patients (56.7%) demonstrated abnormal strain, defined as a GLS <= -19%. Patients with abnormal strain were similar in age and BMI to patients with normal cardiac function. When compared to women with normal strain, those with abnormal strain had lower stroke volume (69.0 ml vs 81.5 ml; p = .001) and ejection fraction (49.6% vs 57.5%; p < .0001). Rates of superimposed preeclampsia were higher (38.2% vs 11.5%, p-value = .02) and a higher proportion of patients in the abnormal strain group delivered before 37 weeks (44.1% vs 19.2%; p = .04).

Conclusion: In a population of parturients with cHTN, we found that more than one-half demonstrated subclinical abnormal cardiac function. The presence of abnormal cardiac strain predates superimposed preeclampsia and preterm delivery. Further studies are needed to validate these findings.