April 2016
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Increasing the Success Rate of Diabetic Limb Salvage

A recent report from the International Diabetes Federation (IDF) showed that Singapore has the second-highest proportion of diabetics amongst developed countries. 10.53% of people here between the ages of 20 and 79 – after correcting for age differences between countries – suffer from the chronic disease.

This is a worrying situation, especially when one considers that around 700 major lower limb amputations due to complications from diabetes, take place a year (approximately two per day). These sobering numbers reflect the grim outcomes that diabetics with peripheral arterial disease (PAD) face if they are not well managed.

 What is Peripheral Arterial Disease (PAD)?

Peripheral Arterial Disease (PAD) is a medical condition that is commonly seen in diabetics wherein the arteries of the lower extremities are narrowed or blocked by cholesterol, blood clots, and scar tissues (“plaque”), resulting in reduced blood flow to the legs and feet. The condition not only causes gradual tissue death in the legs; it also makes the affected limb(s) susceptible to infection. If left untreated, gangrene will set in, which would warrant lower limb amputation.

Two Symptom Groups of PAD

Patients with PAD are classified according to two progressive symptoms groups.

Intermittent Claudication is the most common symptom. It is characterized by severe cramping pain in the thigh, calf or foot of the affected limb, which manifests after walking a repeated and/or fixed distance or after a specific duration of exercise and is relieved by standing still (but not while sitting down).

At this stage, PAD is diagnosed by the weakness or total absence of pulses in the affected limb or foot. Other clinical tests that can aid in the diagnosis include Ankle Brachial Pressure Index (ABPI) and ultrasound of the arteries of the lower extremity.

Critical Ischemia and Tissue Loss occurs if the limb that is already symptomatic of intermittent claudication is left untreated. At this stage, the affected limb is noticeably pale and cold. Pain occurs both at rest and lying down, and can only be relieved by dangling it (because of improved blood flow due to gravity). Patients are also prone to infection. Small wounds may lead to purulent, non-healing foot ulcers, ultimately leading to gangrene which is life-threatening, thus necessitating lower limb amputation.

Treatment of PAD

Patients with diabetes and PAD can benefit greatly from a holistic three- prong approach to prevent major lower limb amputations.

Control of risk factors and exercise therapy

This forms the cornerstone of treatment for patients with diabetes and PAD. Our aim is for patients to have optimal blood glucose, cholesterol and blood pressure levels. This can be achieved by taking the correct types of medication in the right doses to control these risk factors. Patients are also started on anti-platelet drug therapy (aspirin or clopidogrel). Anti-platelet therapy has been proven to reduce the risk of developing a heart attack or stroke in PAD patients.

For patients with intermittent claudication, exercise therapy is also encouraged. This involves getting patients to continue walking despite the pain.The aim of exercise therapy is to encourage smaller collateral arteries to enlarge and grow so as to induce new supplementary blood supply to the limb muscles.

Improvement of arterial blood flow

Another key pillar of treatment involves improving the blood flow in the narrowed and blocked main arteries to the limb.This can be done using minimally-invasive angioplasty, stenting techniques or open bypass surgery.

  • Angioplasty: With the patient under local anesthesia or light sedation, a guide wire is inserted via a small puncture wound through the groin or foot arteries. A balloon is inflated to force the artery to re-open.
  • Stenting: In addition to a balloon, metal stents are used to keep the arteries open to prevent future narrowing or blocking.
  • Open Bypass Surgery: A lower limb vein is harvested from the patient’s leg and used as a bypass for the blocked artery.

Control of wound infections

The third pillar is early and adequate treatment of wound infections. When detected early, antibiotics targeting specific bacteria can be prescribed according to wound cultures. Infected tissues are extensively removed while taking care to preserve a functional lower limb and foot. Major amputations are avoided unless absolutely required.

After surgery to remove infected tissues, the resultant wounds are then cared for using a wide-range of techniques. These include special anti-bacterial and negative pressure wound care dressings. Sometimes, skin/muscle flap or skin grafts may be required to cover the wounds so as to accelerate wound healing. This process then allows the patient to regain their mobility and resume their activities of daily living.

Early Intervention Is Necessary For Good Outcomes

Early intervention for diabetics with PAD is crucial in ensuring good outcomes. The rapidly improving techniques and technology such as angioplasty and stenting now offer most patients a lower risk solution to saving their lower limbs.

When combined with advanced wound care techniques, patients whose options for limb salvage were once limited can now look forward to avoiding limb loss. The main aim is to keep patients walking, thus maintaining their quality of life.

The Vascular and Interventional Centre is a leading Singapore-based private clinic dedicated exclusively to the care of disorders relating to the circulatory system, primarily the arteries and veins.