Relationship Between Risk Stratification Scores and Sublingual Microcirculatory Monitoring in Major Vascular Surgery Patients: Preliminary Results

IntroductionRisk stratification is important in high-risk vascular surgical patients given the risk of the presence of various comorbidities, such as ischaemic heart disease. Analysis of microcirculatory variables and their correlation with morbidity and mortality scores could possibly give supplementary information about how to manage these patients in the perioperative setting.The purpose of this study is to investigate the relationship between risk stratification scores and microcirculatory variables following aortic (A) and lower extremity bypass (LEB) surgery.MethodsThis retrospective observational study included patients scheduled for A or LEB surgery under general anesthesia at the Universitair Ziekenhuis Brussels between August 2021 and March 2022.All patients underwent general anesthesia with desflurane in combination with remifentanil TIVA. Sublingual microcirculation was measured using the Cytocam-IDF apparatus (Braedius, The Netherlands) twice: 30 minutes before surgery (T1) and 60 minutes following surgery (T2). Measurements were made of the perfused vessel density (PVD) (mm/mm2), the total vascular density (TVD) (mm/mm2), and the microcirculatory flow index (MFI) (AU). Heart rate, arterial blood pressure, and lactate levels were monitored simultaneously. The amount of administered fluids, 24-hour diuresis, as well as the requirement for vasopressors and inotropes during surgery were noted. Subsequently, the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (= P-Possum) and the Vascular Study Group of New England Cardiac Risk Index (= VSG-CRI) were established for each patient.ResultsThe distribution of both study groups proved to be statistically homogenous. No statistically significant correlation could be established between the risk stratification scores (P-possum and VSG-CRI) and the preoperative microcirculatory variables (TVD 1, PVD 1, and MFI 1). Additional findings are displayed in the tables below.DiscussionThe shown correlations are weak, possibly due to the low number of patients enrolled. Our findings lead us to the conclusion that the postoperative TVD and PVD are correlated to mortality and morbidity, respectively, though a larger subset of patients needs to be investigated. In turn, the VSG-CRI appears to be related to the physiology, morbidity, and mortality scores, but not with the P-Possum's operational severity score.