Peripheral Arterial Disease

Functional and Anatomical Assessment

The Ankle-Brachial Pressure Index (ABI) is the primary reference point. Combined with stress testing it reveals exercise-induced pressure decreases, recovery times and exercise tolerance. Simple and reproducible, the test must be performed on all patients when lower limb arterial insufficiency is suspected. The ABI relates to the relationship between two pressures (mmHg), i.e. the dorsalis pedis or posterior tibial arteries (whichever is highest) at the foot and the brachial pressure. Normally the ABI is 0.95 - 1.00 and should be constant or increase following exercise. In the presence of disease, the ABI decreases in proportion to the severity of stenoses and/or occlusions. Once the ABI is obtained, the patient is exercised on a treadmill at a set speed and gradient. On completion of the exercise the ABI is measured and if abnormal is recorded until it returns to the pre-exercise level. This recovery-time indicates the extent of collateralisation, i.e. the more severe the disease, the longer the recovery time. Data can be used to immediately exclude suspected disease or provide a quantitative assessment for serial review.

Capillary skin flow or small vessel assessments via PPG is also helpful in diagnosing Thoracic Outlet Syndrome, Raynaud's and acute digital ischaemia. It is useful in assessing a patients' response to pharmacological intervention and helps to determine flow in situations where the ABI may not accurate, especially in diabetics.

Colour Duplex Imaging pinpoints the site of stenoses and determines their significance and/or length of occlusion in native vessels or bypass conduits. The combination of the ABI and CDI enables the clinician to determine management; CDI is also used to assess major vessel aneurysms and anatomical anomalies.

Indications:

• Acute and Chronic Limb and Digital Ischaemia
• Adventitial Cystic Disease
• Arterio-Venous Fistulas
• Pulsatile Masses and False Aneurysms
• Femoro-Popliteal Graft Surveillance
• Intermittent Claudication
• Non-healing foot/digit lesions
• Popliteal Aneurysms
• Popliteal Entrapment
• Pre-operative Orthopaedic Surgical Assessment
• Serial Examinations of Peripheral Arterial Disease
• Serial Examinations Post-Angioplasty/Endoluminal Stent Placement
• Subclavian Stenosis and Steal Syndrome
• Thoracic Outlet Syndrome
• Trashing of the foot

Patient Preparation:

Nil preparation required.

Examination Duration:

30-60 minutes