TcPO2 is also used to define amputation levels as values of >50 mm Hg predict a good likelihood of surgical wound healing, whereas healing is uncertain at values of 30–50, and improbable at values of <30 [64]. Duplex ultrasonography (echo Doppler) allows the morphological/functional study of the vascular tree [65]. According to some experts, the information provided by duplex scans is sufficient to indicate which patients should undergo revascularisation, but others believe further diagnostic evaluations such as magnetic resonance (angio-MR) or computed tomography angiography (angio-CT)

are necessary. It needs to be underlined that the American College of Cardiology/American Heart Association guidelines recommend the use of angio-MR rather than angio-CT because it allows better definition and leads to fewer technique-related risks [66]. Invasive arteriography is never considered a diagnostic technique per se, but represents the first step in EGFR inhibitor endovascular therapy; it can only be proposed check details for diagnostic purposes in cases in which the other methods have failed to define the extent and

topography of stenotic/obstructive arterial disease. The preoperative evaluation of diabetic patients at risk of limb loss is a much-debated subject because the need to characterise the arterial bed of patients with advanced vasculopathy in a detailed manner conflicts not only with the need to be as uninvasive as possible but also with the high costs of the most advanced diagnostic techniques. Furthermore, despite the tumultuous progress of vascular imaging techniques, none can be considered a gold standard that satisfies all diagnostic needs. The correct evaluation of patients with PAD cannot be limited to the lower limbs but should also include the aortic vessels, abdominal aorta and renal arteries because this would reduce the number of co-morbidities associated with revascularisation. The techniques currently used for vascular studies are duplex ultrasonography, angio-CT and angio-MR. Duplex ultrasonography is considered to be the most important and, in many centres, is the only technique used before revascularisation

procedures. One of its main advantages is that it provides information concerning the haemodynamics of the obstructive arteriopathy buy Obeticholic Acid and the state of run-off [67]. However, it has often been limited by its operator dependence and the patient’s condition [68], although these factors certainly have less impact in centres that carry out a large number of examinations. Nevertheless, a complete evaluation including the renal arteries, the abdominal aorta, the iliac axes, the femoro-popliteal axis and leg vessels takes a long time. The use of angio-CT and angio-MR has made it possible to obtain repeatable and panoramic images that not only assist the planning of the revascularisation procedure but also allow the simultaneous evaluation of any other area of vascular disease in just a few minutes [69].