Evaluation of clinical tests to assess perfusion in chronic critical limb ischemia

Abstract

Background: Evaluation of macro- and microcirculatory tests to confirm diagnosis, and recognize perfusion changes in chronic critical limb ischemia (CLI).

Patients and methods: Forty-two consecutive patients with CLI examined at the University Hospital Bern, with 21 included in this prospective follow-up analysis. Patients underwent serial clinical examinations, and assessment of the macro- (ankle arterial pressure [AP], great toe pressure [TP], oscillography) and microcirculation (transcutaneous partial oxygen pressure [tcPO2] recumbent, sitting, O2-inhalation; capillary microscopy) at baseline, 6 weeks after revascularization (group 1; [n = 11]), or after 10 weeks in patients unsuitable for revascularization (group 2; [n = 10]). Clinical improvement was considered to indicate increased perfusion.

Results: Eleven patients with revascularization (11/11), and 2 without revascularization (2/10) showed clinical improvement. AP measurements were not reliable or feasible in 9 (43%), TP in 4 patients (19%), respectively. All measurable pressures were in accordance to clinical course. Oszillography gave a moderate perception of perfusion changes. Baseline tcPO2 levels were critical (< 30 mmHg) in all 21 patients, whereas follow-up gave poor correlation with the clinical course. Reliability to detect perfusion changes increased by adding provocation manoeuvers in patients with clinical improvement (39% [5/13] recumbent, 77% [10/13] sitting, 85% [11/13] O2-inhalation). Capillary microscopy revealed a relevant pathology at the forefoot level in all patients with feasible examinations (18/21), and significant improvements according to the clinical course in 92% of patients (12/13).

Conclusions: TP measurements represented most reliable test to confirm diagnosis and disclose improved perfusion in CLI. TcPO2 measurements in recumbent position gave unreliable results, improved by provocation manoeuvers. Capillary microscopy was reliable, but time consuming and limited by anatomical restrictions.