Intraprocedural Transcutaneous Oxygen Pressure and Systolic Toe Pressure Measurements During and After Endovascular Intervention in Patients with Chronic Limb Threatening Ischaemia.

Objective: The aim of this study was to evaluate changes in transcutaneous oxygen pressure (tcpO) and systolic toe pressure (TP) during endovascular intervention.

Methods: This was a single centre prospective, non-randomised, observational feasibility study. Patients with chronic limb threatening ischaemia (CLTI) due to infrainguinal disease scheduled for endovascular treatment were included between March 2018 and December 2019. TcpO was measured continuously bilaterally at foot level throughout the procedure and at follow up. Specific time points during the intervention were chosen for comparison to baseline (before arterial puncture): average tcpO level five minutes prior to percutaneous transluminal angioplasty (PTA); 10 minutes after PTA; and at completion. Bilateral TP was recorded using laser Doppler flowmetry before arterial puncture, at completion, and at clinical follow up. Angiograms were analysed for successful revascularisation and vascular lesions classified according to the Global Limb Anatomical Scoring System (GLASS). Rutherford and WIfI (Wound, Ischaemia, and foot Infection) classifications were registered, as well as clinical outcome.

Results: Twenty-one patients completed the study. Completion angiograms showed inline flow to the foot in all but two patients. Median time to follow up was 10 weeks (range 8 - 13 weeks) and all patients except one improved clinically. TcpO decreased during the initial stage of the intervention, from before arterial puncture to five minute average before PTA (p < .001) and did not recover to above baseline values at the end of intervention. TcpO increased significantly at follow up (p < .001). TP increased statistically significantly during intervention (p < .001) and at follow up (p < .001) compared with baseline.

Conclusion: TcpO and TP measurements are safe and feasible non-invasive techniques for haemodynamic monitoring during endovascular revascularisation. TP increased significantly immediately after completion of the successful intervention, whereas tcpO did not. Both TP and tcpO demonstrated a significant increase at the 10 week follow up.