Association of left atrial strain with hypertension in pregnancy: a prospective observational study.

Introduction

Maternal hypertension, be it gestational or pre-existing, has been a health concern throughout the modern world. Although advances in healthcare have drastically improved the outcome of pregnancies in the past decade or so, the increasing age of expectant mothers, as well as the prevalence of hypertension in the general population and its associated complications, have dealt a different dilemma for current medical practitioners. Hypertension was documented as the 3rd third leading cause of maternal mortality in the Philippines. Studies also showed that Filipinos, when compared to their other Asian counterparts, have a higher incidence of maternal hypertension and its complications. Left atrial strain, a non-invasive, early marker of diastolic dysfunction, has been studied as predictor of chronicity of cases of gestational hypertension. As of writing of this paper, no local study using left atrial strain has been conducted on Filipino people, less so for pregnant women. Hence, further investigation to determine the baseline values and the effect of hypertension in left atrial strain in this population is warranted.

Objectives

This study aims to determine the relationship between left atrial strain using 2D echocardiogram and the presence of hypertension in pregnant Filipino women.

Methods

This was a single center, prospective, cross-sectional observational study involving pregnant patients seen at a tertiary hospital. The primary endpoint was the difference in left atrial strain and compliance between hypertensive and non-hypertensive subjects. For comparison, demographics and other systolic and diastolic echocardiographic parameters were evaluated. A sub-analysis between gestational and chronic hypertensive patients was also done.

Results

Twenty-six pregnant patients between 20 to 38 weeks age of gestation were divided into hypertensive (n=7) and normotensive (n=19) groups. Age (p=0.938), gestational age (p=0.909), and other co-morbidities were comparable between both groups. The left atrial reservoir strain (LASr) was significantly lower in hypertensive patients (32.15 ± 6.17%) compared to normotensive patients (43.85 ± 4.50%), indicating impaired left atrial function in hypertensive individuals (p<0.001). Left atrial compliance was also significantly lower in the hypertensive group (p=0.006), suggestive of elevated filling pressure. Comparison between gestational (n=2) and chronic hypertensive patients (n=5) yielded minimal difference in strain values.

Conclusion

Aside from the physiologic decrease in left atrial strain in pregnancy, the presence of hypertension further decreases left atrial function, specifically, the left atrial reservoir strain and compliance, despite normal standard echo parameters. Its implication on the future cardiac complication requires further investigation.

LA strain: Normotensive pregnant woman

LA strain: Hypertensive pregnant woman