SPP and wound healing in hemodialysis patient

Background : Patients with chronic limb-threatening ischemia are often on hemodialysis. It is unclear which skin perfusion pressure (SPP) values, i.e., those measured immediately after hemodialysis on a hemodialysis day or those measured on a non-hemodialysis day, reflect the actual wound healing course in chronic limb-threatening ischemia. Methods : Eighteen patients undergoing hemodialysis (49 measurements) who were treated for leg ulcers due to critical limb ischemia were included in the study. The SPP values were divided into two groups : those measured immediately after hemodialysis (HD day group) and those measured on non-hemodialysis days (non-HD day group). The wound healing outcomes were investigated. The cutoff SPP value for predicting wound healing was set to ≥ 35 mmHg. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SPP in each group were measured. The relationship between SPP and blood pressure was analyzed by regression analysis. Results : Significant differences were observed in the positive predictive value (HD day : 100%, non-HD day : 50% ; P = 0.002), The correlation coefficient was 0.698 in the HD day group and 0.292 in the non-HD day group. Diastolic blood pressure had a significant effect on SPP (P = 0.039). Conclusions : The measurements are best taken immediately after hemodialysis for more accuracy