More detailed investigations can be organised on an individual basis. If the patient is admitted to hospital, then relevant NICE recommendations should be followed.24 Ankle brachial pressure index (ABPI). Although there is controversy and confusion surrounding the interpretation of ABPIs in diabetes patients, the recommendation is still that all patients should have
a measurement recorded. This reading, however, should be interpreted carefully. Recent OSI906 NICE guidance in PAD gives details on the practicalities of ABPI measurement.10 Incompressible vessels at the ankle can make ABPI interpretation difficult, and the measured pressure artificially elevated. There should be a low threshold for obtaining formal vascular assessment in patients with ABPI values >1.3, particularly when wound healing is delayed, or when foot pulses are absent on palpation. Waveform patterns heard with a hand-held Doppler are useful but take time to learn. ABPIs of <0.5 signify the presence of severe PAD;
however, the result in itself does not establish the diagnosis of CLI. Most patients with ABPIs <0.5 will not require intervention in the absence of rest pain or tissue loss. Palbociclib The absolute pressure in mmHg is a more useful value than the ABPI ratio as a predictor of wound healing Toe pressures. Toe pressures have the advantage of being more representative of the perfusion to the distal extremity than ankle pressures and are useful when the calf arteries are incompressible. In the healthy individual the toe pressure is usually Resveratrol 0.8–0.9 of the brachial pressure. Ischaemic rest pain usually exists when the absolute toe pressure is <30mmHg,5 and recommendations from the European Society of Vascular Surgery suggest that healing is severely impaired when the toe pressure is <30mmHg.25 The authors' opinions are that ankle pressures of 50–70mmHg and toe pressures of 30–50mmHg remain a ‘grey’ area for healing and the feet require close observation. Recent NICE guidance in PAD10 has recommended Duplex ultrasonography
as the first-line investigation in all patients in whom revascularisation is being considered. If further imaging is then required, contrast enhanced magnetic resonance angiography (MRA) is advised with computed tomography (CT) angiography only if MRA is contraindicated, not tolerated or not available. Duplex. Duplex imaging has the advantage over other forms of imaging as it gives real-time information about blood flow in a vessel. It can also provide functional information on the severity of an arterial stenosis and its effect on blood flow. The calf vessels can be more difficult to assess due to their size, calcification and in the presence of more proximal disease. MRA. MRA avoids the need for ionising radiation and is better at assessing the lumen of calcified vessels than CT. This has obvious value when looking at calcified tibial vessels. However, optimal imaging does require contrast. CTA – CT angiogram.