The role of visceral obesity and insulin resistance in right ventricular function in patients with metabolic syndrome
Authors: Sedaia E , Revenco V 
Published: October 2021

Abstract

Background
Evidence shows a strong relationship between visceral obesity, insulin resistance, metabolic syndrome (MetS) and cardiovascular disease risk. The role of right ventricular (RV) function is indisputably important in estimating of patient's prognosis. Multiple studies demonstrate that visceral fat represents a metabolically active organ, secreting a plethora of vasoactive substances that may have impact on cardiometabolic risk profile of the patient, especially under the circumstances of MetS.

Purpose
The objective of our study was to evaluate the role of visceral obesity and insulin resistance in RV function in patients with MetS.

Methods
The study included 100 subjects with MetS (mean age 53±8.9 years) and 100 controls without MetS (mean age 51±9.3 years, P=0.08). MetS was defined by ≥3 criteria of IDF, AHA/NHLBI. The participants of the study underwent complete 2D echocardiography and abdominal sonography with the assessment of diastolic function of RV: the ratio of early and late diastolic tricuspid flow velocities (Et/At), the ratio of early diastolic tricuspid flow velocity and early diastolic tricuspid annular velocity (Et/e't), Et deceleration time (DT); systolic RV function: TAPSE, ejection fraction of RV (EF); global RV function: Tei index of RV (by pulsed and pulsed tissue Doppler); visceral obesity sonographic parameters: epicardial fat thickness (EFT), intra-abdominal fat thickness (IFT), abdominal wall fat index (AWFI). The status of insulin resistance was determined by HOMA-IR≥2.5.

Results
All the parameters of RV diastolic function, as well as Tei index, were significantly changed in MetS group (P&lt;0.05 for all parameters). Systolic function of RV showed no statically important differences among the groups (TAPSE 20,4±1,7 mm vs. 21.4±2.3 mm, P=0.087; EF RV 53±3% vs. 54±4%, P=0.092). In patients with MetS we found important correlations of diastolic parameters of RV (Et/At, Et/e'T, EtDT) with EFT (respectively: r=−0.524, P&lt;0.001; r=0.291, P&lt;0.001; r=0.692, P&lt;0.001), IFT (respectively: r=−0.342, P&lt;0.001; r=0.335, P&lt;0.001; r=0.592, P&lt;0.001), and AWFI (respectively: r=−0.426, P&lt;0.001; r=0.212, P=0.002; r=0.538, P&lt;0.001). In MetS group Tei index of RV (determined by pulsed and pulsed tissue Doppler) showed important correlations with EFT (r=0.623, P&lt;0.001; r=0.618, P&lt;0.001), IFT (r=0.498, P&lt;0.001; r=0.530, P&lt;0.001) and AWFI (r=0.313, P=0.001; r=0.307, P=0.001). In patients with HOMA-IR ≥2.5 risk for diastolic dysfunction of RV was 5 times higher. Systolic RV function did not show important correlations with selected parameters of visceral obesity. Multivariate regression analysis showed that EFT and HOMA-IR were independently associated with RV global and diastolic dysfunction in patients with MetS (P&lt;0.05).

Conclusions
Our findings support that visceral obesity (especially determined by EFT) and insulin resistance are associated with diastolic and global dysfunction of RV in patients with MetS.

Funding Acknowledgement
Type of funding sources: None.