THE PREDICTIVE VALUE OF LASER-DOPPLER FLUXMETRY AND TRANSCUTANEOUS OXIMETRY FOR CLINICAL OUTCOME IN PATIENTS UNDERGOING REVASCULARIZATION FOR SEVERE LEG ISCHEMIA

Objectives: To investigate the predictive value of laser Doppler fluxm etry and transcutaneous oximetry in 41 patients undergoing technically successful revascularisation for severe leg ischaemia. Design: Toe an d ankle systolic arterial pressures, transcutaneous oxygen tension (tc pO(2)), and stressed laser Doppler fluxmetry at the foot (time to peak laser Doppler flux following 2 min arterial occlusion, t(p) LDF, and the response of LDF to raising the leg 40 cm, the elevated:supine LDF ratio) were measured before revascularisation. Six months later these measurements were compared in those patients who were clinically impro ved, and those who still had symptoms of severe ischaemia or had lost their limb. Setting: Vascular Laboratory, St. George's Hospital, Londo n SW17, U.K. Results: Six months following revascularisation 30 (73%) of the 41 patients had partial or complete symptomatic relief. Six (15 %) had undergone major amputation and five (12%) still had symptoms of severe ischaemia. Before intervention toe and ankle systolic pressure s were similar in the 30 who were improved and the 11 who had lost, or were still at risk of losing, their leg. Pre-revascularisation tcpO(2 ) was significantly lower (18.3 mm Hg vs 33.5 mm Hg; p < 0.05) and t(p ) LDF significantly longer (140 s vs 92 s; p < 0.05) in the 11 patient s who were not clinically improved at 6 months. Whilst pre-revasculari sation toe and ankle pressure below 30 mm Hg and 50 mm Hg respectively identified only 55% of those patients who were not improved 6 months later, a t(p) LDF in excess of 100 s identified 82% (p < 0.05) and was noted in five of the sic amputees. Conclusion: Microcirculatory asses sments performed in patients with limb-threatening ischaemia are likel y to be more deranged in those patients who suffer clinical failure or amputation despite an apparently successful revascularisation procedu re.