Diagnosis methods for PAD
PAD patients may be asked to undergo the below common (mostly non-invasive) tests to diagnose their disease and its staging, and to allow repeated objective measurements over time to detect improvement or deterioration of their PAD, or to indicate if a revascularization (procedure done to restore the blood supply to their leg) was indeed successful.
These tests / examinations may include (but are not limited to):
Patient’s legs and feet are being examined by the doctor while are fully exposed, to detect any changes in skin color and texture (thin and shiny skin, hair loss and trophic skin changes, tissue loss, ulceration and gangrene, skin pallor), and blood flow indicators are also being externally examined - decreased blood pressure or pulse absence / irregularities, in the leg.
Patient’s blood tests help indicating the risk factors for PAD development (lipid profile, cholesterol, coagulation tests). It can also detect blood indicators for organ injury or worsening of peripheral blood supply, by measuring levels of homocysteine (building blocks for proteins), and C-reactive protein (CRP) (produced by the body in response to inflammation), both when are present in high levels in the blood, associated with atherosclerosis.
ABI/TBI (Ankle/Toe-Brachial Pressure Index)
This is a common non-invasive test with high sensitivity and specificity in identifying healthy individuals or diagnosed with PAD, if the result of the ABI exceeds the normal ranges. ABI is the ratio calculated from the blood pressure measured by an inflated cuff placed on the patients’ ankle/toe and compared to the blood pressure measured with by an inflated cuff placed on the patients’ arm.
DUS (Duplex ultrasonography)
This is a common non-invasive ultrasound imaging of the leg suspected with PAD. This imaging approach presents blood vessels structure with blood flow and allows estimation of the vessel diameter and level and velocity of blood flow. DUS is a useful tool to define the locations of lesion/blockage in the artery.
A minimally invasive examination done by injection of contrast agents into the artery via a catheter inserted at the groin area, and by X-rays (fluoroscopy) imaging allowing to view the blood flow, up from the common femoral artery, to the artery in question with the specific blockage, and downstream until the foot. Although the fluoroscopy by X-ray is the most used imaging method for PAD angiography, the doctor may use other imaging modalities prior to the invasive angiography, such as Computerized Tomography Angiography (CTA) or Magnetic Resonance Angiography (MRA), which are both non -invasive. Yet, if the invasive diagnosis is used, it enables the physician to treat the lesion at the same session.
Walking Impairment Questionnaire (WIQ)
This questionnaire is a validated subjective tool to detect changes in the daily walking ability of PAD patients. This questionnaire is filled out by the patient and evaluates the patient’s walking ability, with a focus on walking distance, walking speed and the ability to climb stairs.
A commonly used clinical staging system for describing PAD, can be used as an objective scale to allow doctors to describe and discuss PAD patients using a common terminology. It has seven stages, from Stage 0 (asymptomatic) to Stage 6 (severe ischemic ulcers or gangrene).