The predictive value of microperfusion assessments for the follow-up of tibial bypass grafts

Abstract

ObjectiveWe conducted a prospective evaluation of microperfusion parameters after tibial bypass surgery was performed. Differences between grafts with occlusions during follow-up and patent grafts were analyzed in relation to the pedal arch quality. MethodsPatients receiving tibial bypass grafts for chronic limb-threatening ischemia from 2019 to 2020 were included. Assessment of microcirculation (parameters: hemoglobin oxygen saturation [sO2] and flow) was done by laser Doppler flowmetry and white light spectrometry (oxygen-to-see), supine and in elevation, whereas the macrocirculation was evaluated by the ankle-brachial index and duplex ultrasound examination. The quality of run-off was graded for each patient. Measurements were performed preoperatively, 1 day postoperatively, and after 6 months. Patients with graft occlusions during follow-up (OCCLUDED) and patients without occlusions (OPEN) were compared. ResultsWe included 42 patients (13 women, 29 men; mean age, 76.1 years; range, 60-89 years) were included. The patency of all grafts 1 day after the operation was confirmed by ultrasound examination. The overall analysis of the microcirculation showed significant changes in both the supine and elevated leg position between measurements taken preoperatively, 1 day after the operation, and after 6 months for the parameters sO2 and FLOW (sO2 supine, P = .001; sO2 elevated, P < .001; FLOW supine, P < .001; FLOW elevated, P < .001). The comparison of the values 1 day after the operation yielded significantly decreased microperfusion parameters (both O2 and FLOW) in the group that developed bypass occlusion in the later follow-up period (sO2 supine: OCCLUDED, 35.7% [7.3-65.0] and OPEN, 48.7% [25.0-72.3] P = .011; FLOW supine: OCCLUDED, 27.7 A.U. [12.7-52.7] and OPEN, 57.3 A.U. [16.0-106.7], P = .008). No significant differences in the severity of the arch impairment was found between the OPEN and OCCLUDED groups (P = .651). Absolute values of the parameters sO2 and flow showed no correlation with the pedal arch classification. ConclusionsSignificantly poorer microperfusion was detected postoperatively in patients with later occurrence of graft occlusions despite patent grafts on the first postoperative day. Microperfusion measurements might be a possible tool for the prediction of graft failure.