The role of superb microvascular imaging in detecting low-grade inflammation among adults and those with chronic kidney disease: A preliminary study

Background/aim: Pathophysiologic changes associated with chronic inflammation occur with aging and more prominently in patients with chronic kidney disease (CKD), and an association between chronic inflammation and muscle wasting has been identified. The microcirculation is extremely sensitive to the inflammatory process and actively participates in it. In a healthy adult, angiogenesis is a strictly controlled and rare occurrence. However, aberrant angiogenesis and the development of new tiny blood vessels are known in chronic inflammatory diseases. Superb microvascular imaging (SMI) is a noninvasive technique that can evaluate tiny vessels with low blood flow and provide quantitative data. Our goal was to detect increased blood flow secondary to low-grade chronic inflammation in micro-circulation in the rectus femoris (RF) muscle using SMI.Materials and methods: This cross-sectional study involved 30 patients with CKD, 30 adults without CKD or other chronic illnesses, and 32 young healthy volunteers. This study was conducted in our university hospital between March and December 2021. The RF cross-sectional area (CSA) was measured, and vascular index (VI) values were obtained using SMI. All three groups' RF-CSA and VI values were compared.Results: Although there was no statistically significant difference in RF-CSAs between the groups, the VI values of all three groups were statistically different (p < 0.001). The median (min-max) VI values were 0.90 (0.60-1.30), 0.50 (0.20-1.0), and 0.30 (0.10-0.50) for the CKD, adult control, and young healthy groups, respectively. The VI significantly differentiated patients with CKD from all other patients and the adult control group. When a cutoff value of 6.5 was used for the VI in detecting increased blood supply in RF muscle in patients with CKD, the accuracy, positive predictive value, and negative predictive value were 93.5%, 85.3%, and 98.3%, respectively. Conclusion: SMI can detect increased blood supply caused by low-grade inflammation in the RF muscle.