Effect of revascularization on lower extremity muscle function in combined type 2 diabetes and critical limb threatening ischemia

Background: Critical limb-threatening ischemia (CLTI) and type 2 diabetes (T2D) frequently co-exist and often with less favorable outcome after revascularization. The objective was to evaluate the effects of revascularization on muscle function, perfusion and mitochondrial respiration in patients with combined CLTI and T2D. Methods: A prospective translational observational study. Two groups of patients facing unilateral peripheral revascularization was included: Patients suffering from combined disease with CLTI+T2D (N.=14) and patients suffering from CLTI (N.=15). During pedal exercise testing, calf muscle perfusion was monitored with near infrared spectroscopy (NIRS) and leg arterial volume flow in the common femoral artery with duplex ultrasound. Calf muscle biopsy and subsequent assessment of mitochondrial respiratory capacity on isolated muscle fibers was performed. Tests was performed before and six weeks after revascularization. Results: After revascularization, patients CLTI+T2D improved in muscle force from 8.48 kg (CI: 7.49-9.46) to 13.11 kg (CI: 11.58-14.63), (P<0.001). Conversely, muscle force in patients suffering from non-diabetic CLTI decreased from 10.03 kg (CI: 9.1-10.96) to 9.73 kg (CI: 8.77-10.69), (P=0.042). Muscle oxygenation during exercise improved more in the CLTI+T2D group (6.36 mu M/kg/s [CI: 5.71-7.01] compared to 2.11 mu M/kg/s [CI:1.38-2.83] in the CLTI group; P=0.002). No improvement or difference between groups regarding mitochondrial function was detected. Conclusions: Patients with combined CLTI+T2D, had an unsuspected better effect of revascularization compared to patients with non-diabetic CLTI, in terms of increased muscle force and improved muscle perfusion. Further studies are needed to elucidate the apparent interaction of the CLTI and T2D syndromes.