Diabetic foot is a concern for a specific reason: it is the result of two problems that often add up. One is loss of sensation; the other is poor circulation. And it is precisely blood flow that decides whether a foot wound will heal or not, although it is not the only factor.
Two problems combined
Over time, diabetes can lead to two changes in the foot:
- Neuropathy: loss of sensation. The foot stops signalling pain, so wounds, chafing or burns can go unnoticed, allowing them to progress and become complicated by infection.
- Ischaemia: lack of blood flow. The arteries of the leg and foot narrow and less blood reaches the area.
When they combine, a small injury that goes unnoticed and also does not receive enough blood can turn into an ulcer that will not close.
Why blood flow changes everything
A wound only heals if it receives enough blood: blood carries the oxygen and the elements that repair tissue and fight infection. If the supply is reduced because the arteries are narrowed or blocked, the wound stalls. That is why, in a diabetic foot ulcer, assessing circulation is a priority: it is not enough to treat the wound from the outside if blood is not reaching it from the inside.
Signs that blood flow may be lacking
It is worth seeking advice if you notice in the foot or leg:
- A wound or ulcer that has not closed in weeks.
- A cold, pale foot or one with colour changes.
- Foot pain at rest, especially at night, or calf pain when walking.
- Loss of leg hair, or nails that grow poorly or crack.
We cover this in more detail in the article on the signs of poor blood flow in the diabetic foot.
How blood flow is assessed: vascular diagnosis
The good news is that checking whether blood is reaching the foot is simple and painless. Several tests are combined in a vascular surgery consultation:
- Examination of the pulses in the foot and leg, along with assessment of skin temperature and colour.
- Ankle-brachial index: compares pressure at the ankle with pressure at the arm to estimate the degree of blood flow. You can see what this involves in the article on the ankle-brachial index.
- Doppler ultrasound: a scan that shows in real time how blood is flowing through the arteries and where narrowing is present.
- When an intervention is being considered, this can be complemented with a CT angiogram or arteriography to map the arteries in detail.
With these tests, it becomes clear whether the foot is well supplied with blood or whether there is ischaemia that needs treatment, and the next step is decided.
In diabetic foot my role is clear: check whether blood is reaching the area and, if not, restore blood flow in indicated cases. An ulcer with proper external dressing usually will not heal if the foot is ischaemic underneath. Circulation is the foundation.
Revascularisation
When the arteries are narrowed and this compromises healing, the goal is to restore blood flow. Today this is often done endovascularly, through catheterisation with angioplasty or a stent, and in other cases with surgery using a bypass or other techniques. The choice is made depending on where and how the arteries are affected. The purpose is for enough blood to reach the area so the wound can close and to prevent major complications. You can find more context on the diabetic foot page.
This vascular approach is combined with wound care, diabetes control and, often, adapting footwear and custom insoles to the patient.
In summary
Diabetic foot combines loss of sensation with, in many cases, poor blood flow, and it is circulation that decides whether a wound heals. That is why, faced with an ulcer that will not close, assessing blood flow is a priority. When it is lacking, revascularisation — endovascular or surgical — restores the blood supply and improves healing. Seeking help early is what helps most to avoid complications.