Peripheral Arterial Disease Located in the Feet of Patients With Diabetes and Foot Ulceration Demands a New Approach to the Assessment of Ischemia

Abstract

Peripheral arterial disease (PAD) is common below the knee in diabetes but arteries in the foot are controversially said to be spared of occlusive disease. This is relevant to the convenient site of vascular assessment that is recommended in guidelines. Should assessment be distal at toe/forefoot to detect foot disease or only proximal to detect disease at ankle level? The objective was to determine frequency of PAD at foot and ankle level. This was a cross-sectional observational study, evaluating arterial disease proximally by palpation of pedal pulses and Ankle Brachial Index (ABI), and distally by Toe Brachial Index (TBI), and forefoot transcutaneous oxygen tension (tcpO2), in consecutive patients presenting with foot ulceration. We assessed 301 limbs in 154 patients: 59% of limbs were ulcerated. PAD in the foot was detected in 70% and 74% of limbs by TBI and forefoot tcpO2, respectively, but PAD at ankle level only in 51% and 34% by pulse palpation and ABI, respectively. In limbs with “normal” ABI, PAD was present in the foot in 70% as indicated by low TBI, and in 73% by low tcpO2, with 70% to 64% having associated ulceration, respectively. When compared with arterial waveforms, as a measure of PAD, TBI gave an excellent AUC (area under the curve of the receiver operating characteristic curve) of 0.81 (95% confidence interval: 0.73-0.89), but ABI gave a poor AUC of 0.65 (95% confidence interval: 0.55-0.76). In conclusion, arterial disease is important in the foot and can be detected by TBI, which should be performed even when ABI is normal. Guidelines that recommend TBI only if ABI is artificially raised need updating.

Prognostic and predictive value of ultrasound-based estimated ankle brachial pressure index at early follow-up after endovascular revascularization of chronic limb-threatening ischaemia: a prospective, single-centre, service evaluation

“… 13 The advantage of the pedal acceleration time over our current ankle based eABPI approach is that it also assesses perfusion further distal below the ankle 22 and may pick up remaining foot lesions and not only leg ischaemia potentially similar to toe brachial index. 23 …”

Improving Physical, Physiological, and Psychological Health Outcomes in Patients with Diabetic Foot Ulcers – State of the Art

“…Those with diabetes are more likely to be asymptomatic because of concurrent neuropathy and a significant proportion will have diffuse, below the knee predominant disease and at times limited to the foot level. 23 , 24 In addition to conferring risk for the development of DFU, the presence of PAD is also a marker for slower healing of DFU infection, a higher risk of lower extremity amputation (both major and minor), unplanned hospital admissions, cardiovascular events and mortality. 25 We now recognise that DFU developing on the plantar/pressure regions can still have an additional element of PAD (neuroischaemic DFU) but classically ischaemic lesions, usually presenting with tissue loss and gangrene, are still commonly encountered ( Figure 2 ).…”

The Angiosome-based Revascularization: Overestimated, Misunderstood, or Incomplete?

“…Yet, the angiosome-based revascularization theory does not take into consideration nor evaluates the contribution of tibial of inframalleolar collaterals (Figure 1), which can significantly contribute to the perfusion of the foot especially in diabetic and dialysis patients, where the small artery disease in the foot is particularly evident. 4 According to our personal experience, restoring in-line perfusion to a well-developed collateral network via a proximal angioplasty or bypass suffices to limb salvage and wound healing in most cases.…”