Diabetic foot: why early vascular assessment is decisive for prognosis

A common complication of diabetes with a high risk of amputation

Diabetic foot is one of the most severe complications of diabetes. It is estimated that 15–25% of diabetic patients will develop a foot ulcer during their lifetime, with a high risk of infection, hospitalization, and amputation (1). After amputation, the 5-year overall survival is approximately 70%, dropping dramatically to just 43% following major amputation (4). That is why early assessment is of great importance for patient prognosis.

In most cases, diabetic lesions result from the combination of two major mechanisms:

• peripheral neuropathy, responsible for loss of sensation,

• and lower limb peripheral arterial disease (PAD), which impairs tissue perfusion and wound healing (2,3).

Early identification of these two components is essential, as they directly determine prognosis and therapeutic strategy.

 A major clinical feature: absence of pain

Unlike other conditions, patients with diabetic foot rarely consult due to pain.

As podiatrist Ms. Véronique Labbé-Gentils points out:

“From the very first minute of consultation, the first thing I assess is that my patient has no pain.”

This lack of symptoms is directly related to peripheral neuropathy. It partly explains delayed diagnosis and the severity of lesions at presentation (2).

In practice, patients are most often referred by a healthcare professional (general practitioner, nurse, emergency department) after a wound is discovered, rather than seeking care themselves. 

Three types of lesions, three different prognoses

Management of diabetic foot relies on identifying the type of lesion, which determines evolution and treatment strategy (2).

1. Pure neuropathic lesions

These ulcers occur without significant arterial disease. When treated early, ideally within 48 hours, the prognosis is favorable, with healing times generally between 4 and 8 weeks.

2. Neuro-ischemic lesions

These combine neuropathy and arterial disease. Their management is more complex and primarily requires a thorough vascular assessment (3).

In such cases, revascularization may be necessary, provided it is technically feasible. The presence of medial arterial calcification may complicate or even prevent any revascularization strategy.

3. Pure ischemic lesions

These correspond to advanced forms of arterial disease, often not amenable to revascularization. Management is then frequently palliative, with a high risk of amputation (3), although conservative strategies can now better preserve foot structure.

Vascular assessment: a key element from the first consultation

In the presence of a diabetic foot ulcer, vascular assessment should never be delayed.

The initial clinical examination includes:

• palpation of peripheral pulses (dorsalis pedis and posterior tibial),

• complemented by non-invasive tests.

Several measurements are now available to quickly assess vascular status:

• ankle-brachial index (ABI),

• toe pressure,

• and, secondarily, arterial duplex ultrasound (3).

These tests are essential to guide management of wound care.

As Ms. Véronique Labbé-Gentils emphasizes:

“I will not follow the same protocol at all if the ABI is below 0.9 or if it is normal.”

Adapting management according to vascular status

Vascular status directly determines treatment strategies. It is important to note that in patients with diabetes, arterial calcification can affect ABI reliability. In such cases, measuring TBI (toe-brachial index) is recommended, as ABI values may appear falsely normal, not only elevated, despite underlying arterial disease.

• Abnormal ABI < 0.90 or toe pressure < 30 mmHg indicating critical limb ischemia
  → cautious strategy: drying, limited debridement, avoid techniques promoting moist wound healing, compression therapy in case of arterial wound should not be applied

• Normal ABI ≥ 0.90
  → standard wound care with more active healing strategies

These differences highlight the importance of rapid, objective assessment to avoid inappropriate interventions that may worsen outcomes (2,3).

An organizational challenge: improving the care pathway

One of the main issues today is delayed patient referral.

Many patients present with:

• wounds evolving for weeks or months,

• prolonged ineffective treatments,

• and, most importantly, no recent vascular assessment.

This delay in management directly affects prognosis (1,2).

Another major challenge is the training of healthcare professionals, especially in primary care, that is needed to perform accurate ABI measurements using a Doppler.

Toward a more structured vascular screening approach

Optimal management of diabetic foot relies on a coordinated and stepwise approach:

1. Initial clinical examination (inspection + pulse palpation)

2. First-line assessment (handheld Doppler or measurement with an automated  ABI device

3. Referral to specialized centers to perform additional assessments and provide appropriate care

4. This organization would significantly improve early detection of arterial disease and optimize care pathways (2,3).

Key takeaways

• Diabetic foot is a common complication with a high risk of amputation.

• Peripheral neuropathy masks symptoms and delays diagnosis.

• Vascular assessment is essential from the first consultation.

• Vascular status directly guides treatment strategy.

• Early vascular screening improves prognosis and reduces complications.