Alterations of retinal vessels in patients with sepsis

Abstract

Background and study objective The retina is a window where the microvascular profile can be imaged directly and non-invasively at the bedside. Sepsis is associated with a decrease in microvascular density and its severity is related to mortality [1]. However, features of retinal vessels calibers and density during sepsis are not fully characterized. ObjectivesTo compare the retinal vasculature between septic patients and age matched healthy volunteers. Méthodes Prospective observational study from January 2018 to April 2019 in a third-level ICU. We performed a single fundus imaging using a hand-held digital fundus camera (Aurora, Optomed Oy, Finland) in patients with sepsis or septic shock (n=37) during first 24 hours after ICU admission and compared these data with age-matched healthy controls (n = 20). Image analysis was performed using ARIA software. The average retinal arteriolar and venular caliber were calculated and summarized as the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE). Arteriole–venular ratio (AVR) defined as the ratio of CRAE to CRVE. The density of manually segmentated retinal vessels was calculated using ImageJ software: vascular length density = skeletonized vessel area/total area * 100%. Data are reported as medians with 25th and 75th percentiles. ResultsOut of 37 patients, 35 (95%) were in septic shock, 37 (100%) required mechanical ventilation. Median APACHE II and SOFA scores were 16 (12-20) and 9 (7-11), respectively. Mean arterial pressure (MAP) and cardiac index (CI) were 74 (64-81) mmHg and 2.9 (2.1-4.1) L/min/m2, respectively, and the median norepinephrine (NE) dose was 0.24 (0.10-0.33) mcg/kg/min. Patients with sepsis had a median CRAE of 161.8(146.6-183.2) µm compared with 146.3(141.9-157.7) µm in healthy subjects (p = 0.008). Their median CRVE was 257.6(225.0-286.7) µm compared with 243.7(215.1-272.2)µm in healthy subjects (p = 0.221) and AVR was 0.6(0.6-0.7) compared with 0.6(0.5-0.7) in healthy subjects (p=0.508). We found significant correlation between CRAE and diastolic blood preesure (r=0.35, p=0.047), between arterial tortuosity and systolic blood pressure (r=-0.36, p=0.042). Patients with sepsis showed a significant decrease in retinal vascular lenght density compared with healthy subjects (p=0.001).Conclusion We found retinal signs of arteriolar vasodilation and decreased retinal vascular density in septic patients.