#5834 ALBUMINURIA AND RENAL RESISTIVE INDEX ARE ASSOCIATED WITH MICROVASCULAR REMODELING IN PATIENTS WITH SEVERE OBESITY

Background and Aims Renal hemodynamics is impaired since the early stage of cardiometabolic disease. However, in severe obesity, its noninvasive assessment with ultrasound still fails to provide pathophysiologic and clinical meaningfulness. The aim of the study is to explore the relationship between peripheral microcirculation and renal hemodynamics in severe obesity. Method We enrolled forty-eight patients affected by severe obesity with an indication for bariatric surgery referring to our Clinic. Patients underwent an extensive renal examination with evaluation of eGFR with EPI-Cr formula, albuminuria and urinary TGF-β as indirect markers of kidney fibrosis, paired with Doppler ultrasound to measure renal resistive index (RRI). On the day of the surgery, visceral fat biopsies were collected to perform an ex-vivo complete microcirculatory assessment. Media-to-lumen ratio (M/L), wall-cross sectional area (WCSA) and vascular response to acetylcholine (ACh), alone or co-incubated with L-NAME, were measured. Results Patients were stratified according to their normotensive (NT) or hypertensive (HT) status. HT had lower eGFR and higher RRI compared to NT. The presence and extent of albuminuria were similar between the two groups, while TGF-β was slightly higher in the HT group (p = 0.059). Concerning microcirculatory assessment, there were no differences between groups as regards the microvascular structure, while the vasorelaxation to ACh was lower in HT (p = 0.039). Multivariable analysis showed a relationship between M/L and RRI (p = 0.022, St.β 0.38) and between albuminuria and the inhibitory response of L-NAME to Ach vasodilation (p = 0.039, St. β = -0.36). Notably, all these correlations were consistent also after adjustment for confounding factors. Conclusion The RRI and albuminuria relationship with microvascular remodeling in patients affected by severe obesity supports the clinical implementation of RRI to improve risk stratification in obesity and suggests a tight pathophysiologic connection between renal hemodynamics and microcirculatory disruption.