Abstract MP68: The Correlation Between Left Atrial-left Ventricular-arterial Coupling And Circadian Rhythm Of Blood Pressure In Hypertension

The Correlation between Left Atrial-Left Ventricular-Arterial Coupling and Circadian Rhythm of Blood Pressure in Hypertension Objective: Hypertension induces left atrial (LA) and left ventricular (LV) dysfunction, and arterial stiffness increased. In this study, we further investigated the association between LA-LV-arterial coupling and circadian rhythm of blood pressure (BP) in essential hypertension (HT). Design and Methods: We enrolled 289 HT patients which were evaluated by 2 dimensional speckle tracking echocardiography (2D-STE), ambulatory 24-hour BP monitoring (ABPM) and carotid-femoral pulse wave velocity (PWV). According to BP patterns, these patients were divided into two groups, which included dippers (n=109), patients with a >10% reduction in BP at nighttime; non-dippers (n=180), patients with a <10% reduction in BP at nighttime. 2D-STE based LA and LV strains were studied and the following parameters were measured, LV global longitudinal strain (GLS), LA reservoir strain (LA S-S ), LA conduit strain (LA S-E ), and LA booster pump strain (LA S-A ). LA stiffness index (LASI) defined as the ratio of E/e' to LA S-S , and PWV-to-GLS ratio (PWV/GLS) were calculated to reflect LA-LV-arterial coupling. Furthermore, we also explored the correlation between LASI (or PWV/GLS) and ambulatory blood pressure indexes. The related factors were evaluated by multivariate linear regression analysis to find the independent factors. Results: LASI was significantly higher in non-dippers (0.35±0.24) than dippers (0.29±0.12) ( p <0.05). PWV/GLS was significantly higher in non-dippers (-90.30±34.13) than dippers (-79.62±25.84) ( p <0.05). LA S-S , LA S-A and LV GLS were significantly lower in non-dippers than dippers ( p <0.05). Multivariate linear regression analysis revealed that LV mass index (LVMI), PWV/GLS, nighttime mean SBP (n-SBP) and nighttime mean DBP (n-DBP) were independently correlated with LASI; LASI and n-SBP were independently correlated with PWV/GLS. Conclusions: LA and LV myocardial mechanics, and LA-LV-arterial coupling were associated with circadian rhythm of BP. Nocturnal systolic BP was the independent risk factor of abnormal LA-LV-arterial coupling in HT.

Left ventricular-arterial coupling as a predictor of stroke volume response to norepinephrine in septic shock – a prospective cohort study

Background Left ventricular-arterial coupling (VAC), defined as the ratio of arterial elastance (Ea) to left ventricular end-systolic elastance (Ees), is a key determinant of cardiovascular performance. This study aims to evaluate whether left VAC can predict stroke volume (SV) response to norepinephrine (NE) in septic shock patients. Methods This was a prospective cohort study conducted in an intensive care unit of a tertiary teaching hospital in China. We recruited septic shock patients who had persistent hypotension despite fluid resuscitation and required NE to maintain mean arterial pressure (MAP) > 65 mmHg. Those patients in whom the target MAP was not reached after NE infusion were ineligible. Echocardiographic variables were measured before (baseline) and after NE infusion. SV responder was defined by a ≥ 15% increase in SV after NE infusion. Results Of 34 septic shock patients included, 19 (56%) were SV responders. Before NE infusion, SV responders had a lower Ees (1.13 ± 0.24 mmHg/mL versus 1.50 ± 0.46 mmHg/mL, P = 0.005) and a higher Ea/Ees ratio (1.47 ± 0.40 versus 1.02 ± 0.30, P = 0.001) than non-responders, and Ea in SV responders was comparable to that in non-responders (1.62 ± 0.36 mmHg/mL versus 1.43 ± 0.28 mmHg/mL, P = 0.092). NE significantly increased Ea and Ees in both groups. The Ea/Ees ratio was normalized by NE administration in SV responders but unchanged in non-responders. The baseline Ea/Ees ratio was positively correlated with NE-induced SV increases (r = 0.688, P < 0.001). Logistic regression analysis indicated that the baseline Ea/Ees ratio was a predictor of SV increases induced by NE (odd ratio 0.008, 95% confidence interval (CI): 0.000 to 0.293), with an area under the receiver operating characteristic curve of 0.816 (95% CI: 0.646 to 0.927). Conclusions The left VAC has the ability to predict SV response to NE infusion in septic shock patients. Trial registration Chinese Clinical Trial Registry, ChiCTR1900024031, Registered 23 June 2019 - Retrospectively registered, http://www.chictr.org.cn/edit.aspx?pid=40359&htm=4.