Left atrial stiffness index is associated with metabolic syndrome and independently related to urine albumin-creatinine ratio in young subjects with hypertension
Authors: Bazdyreva E.I , Ezhova N , Khomova I.A , Shavarova E.K , Kobalava Z.D 
Published: October 2021

Abstract

Background and objective
Left atrial (LA) functional decline seems to be the earliest sign of hypertension-related heart damage detectable with echocardiography for the moment. Left atrial stiffness index (LASI) is a novel index reflecting both LA function and LA–left ventricular (LV) coupling. Early detection of hypertension-mediated organ damage (HMOD) is critically important in clinical decision making in certain groups of patients, such as young persons with first time diagnosed HTN. We intended to analyze the relations of LASI with office and 24 hours blood pressure levels and HMOD characteristics in subjects with HTN aged of 18 to 45 years.

Methods
We included 78 young subjects (median of age 23 [21; 25] years, mean BMI 25,9±4,7 kg/m2, median 24 hours systolic blood pressure (SBP) and diastolic blood pressure (DBP) 134,0 [128,8; 143,3] and 79,5 [74,0; 88,0] mm Hg, respectively) with HTN diagnosed with 24-hours ambulatory blood pressure monitoring (ABPM) according to ESH guidelines criteria (2018). Most patients (73%) had masked HTN. We performed routine clinical evaluation, including registration of anthropometric characteristics and blood and urine tests, central pulse wave assessment with applanation tonometry and echocardiography including two-dimensional speckle tracking. LASI was calculated as E/e$'$ to left atrial longitudinal strain during reservoir phase (LASr) ratio. We performed correlation analysis and multiple linear regression analysis to investigate the relationship between LASI, LASr and variables indicating presence of HMOD.

Results
Correlation analysis did not reveal any significant associations of LASI and LASR with office and ambulatory BP values. Both LASI and LASr were correlated with age, body mass index (BMI), waist circumference (WC) (r=0,312, p&lt;0,05 and (−0,354), p&lt;0,01) and HOMA-IR (r=0,551, p&lt;0,001 and (−0,345), p&lt;0,01). LASI had stronger correlation with albumin-creatinine ratio (ACR) than LASr (r=0,550, p&lt;0,001 vs (−0,288), p&lt;0,05, respectively). Glomerular filtration rate (GFR) was associated with LASI: r=−0,329, p&lt;0,01 but not with LASr. Left ventricular mass index (LVMI) also had a significant correlation with LASI only: r=0,284, p&lt;0,05 as had carotid-femoral pulse wave velocity (cfPWV): r=0,275, p&lt;0,05. We performed multiple linear regression analysis in which LASI remained related to ACR independently of age, sex, BMI, WC, HOMA-IR, GFR and 24 hours SBP and DBP (β=0,306, p&lt;0,05) while LASr lost the association. The link between LASI and other HMOD markers (GFR, cfPWV, LVMI) got insignificant in multiple regression analysis.

Conclusion
Early left atrial functional impairment is associated with overweight, abdominal obesity and insulin resistance in young never treated patients with HTN, while impact of elevated BP in HTN of low grades seems to be not so important. LASI in contrast with LASr is independently related to albuminuria but not with other HMOD markers

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): RFBRRUDN University program 5-100