Characterization of left atrial function during cardiac (reverse) remodeling induced by pregnancy

Abstract

Abstract Introduction The hemodynamic overload in pregnancy leads to cardiovascular remodeling, characterized by enlargement of left atrial (LA) and ventricular (LV) volumes associated with impaired LV relaxation, maintaining preserved systolic function. These changes are reversible during postpartum. Few scientific evidence has been published about LA function yet. Purpose To assess the changes in LA function through two-dimensional speckle tracking echocardiography analysis during pregnancy and its recovery up to 1 year after delivery and to determine potential predictors of its progression. Methods This prospective cohort study included volunteer pregnant women (healthy, obese and/or hypertensive and/or with gestational diabetes) recruited in two tertiary centers between 2019 and 2021. Women were evaluated by transthoracic echocardiography at the 1st trimester [1T, 10-15 weeks, baseline], 3rd trimester [3T, 30-35 weeks, peak of cardiac remodeling] of pregnancy as well as at the 1st, 6th and 12th month after delivery (during RR). Generalized linear mixed-effects models evaluated the extent of RR, including the variation of left atrial strain and its potential predictors. Results We included 130 pregnant women with a median age of 33 [30,36] years, 39,2% multiparas. Fifty-four (41.5%) were diagnosed with at least one cardiovascular risk factor. A significant enlargement of LA volume (24 [22, 28]mL/m2 to 29 [25, 33]mL/m2, p<0.001) associated with the increase of E/e’ (5.85 [5.08, 6.36] to 6.70 [5.67, 7.82], p<0.001) was observed from 1T to 3T, both recovering as soon as 1 month after delivery (LA volume: 29 [25, 33]mL/m2 to 24 [20, 27] mL/m2, p<0.001; E/e’: 6.70 [5.67, 7.82] to 5.70 [4.82, 6.47], p<0.001). Regarding LA function, a significant reduction of LA strain was verified from 1T to 3T (35 [31, 41]% to 31 [29, 36]%, p<0.001), recovering 6 months postpartum (31 [29, 36]% to 33 [30, 38]%, p=0.035). Systemic vascular resistance seemed to be an independent predictor of lower LA strain (-3.83 [-6.40, -1.25], p=0.004). The presence of cardiovascular risk factors (-0.80 [-2.28, 0.68], p=0.287), smoking habits (-1.26 [-2.82, 0.30], p=0.112), parity (-0.33 [-1.93, 1.27], p=0.684) and age (-0.11 [-0.29, 0.08], p=0.257) showed a non-significant impact in LA strain. Conclusion Despite the recovery in diastolic function and LA volume 1 month after delivery, the LA function only significantly improved 6 months later. Systemic vascular resistance was revealed as an independent predictor of LA strain.