Peripheral Arterial Evaluations
Lower Extremity Arterial Evaluation
Lower Extremity Arterial Evaluation is an excellent diagnostic tool that accurately reports the extent of arterial insufficiency or occlusive disease and localizes and quantifies stenoses within the lower extremities utilizing a non-invasive approach. The presence, size and location of aneurysms and pseudoaneurysms can also be identified using this exam. Particularly helpful is the ability to non-invasively differentiate true claudication from pseudoclaudication (e.g., leg pain of non-vascular etiology).
- Chronic arterial occlusive disease
- Symptoms of Claudication – calf, thigh and/or hip pain with walking or exercise that resolves with short rest
- Rest pain – persistent severe ache in the foot that is present at rest
- Acute limb ischemia: pain, pallor, pulselessness , paresthesias (burning or tingling), paralysis, and perishing cold (freezing cold feeling, a painful cold temperature)
- Follow-up post PTA/stenting
- Follow-up post bypass grafting
Routine testing involves measurements of resting ankle-brachial indices (ABI) followed by measurements after treadmill exercise (unless contraindicated by the patient’s cardiac status or mobility).
If ankle pressures are abnormal, either at rest and/or following exercise, duplex ultrasound scanning is performed to determine the location and severity of arterial lesions. Specific arteries examined include the abdominal aorta, common and external iliac arteries, common and superficial femoral arteries, popliteal, posterior tibial, anterior tibial and peroneal arteries.
Toe pressures measured by photoplethysmography are performed selectively in patients when there is evidence of medial calcification, any foot symptoms or signs of ischemia or when ankle pressures were not able to be taken. All examinations are performed bilaterally unless otherwise specifically requested.
Special instructions for patients – No food or drink (except water with medications) 8 hours prior to the Lower Extremity Arterial exam. Diabetic patients should eat and take medications as usual.
Upper Extremity Arterial Duplex
Measurements of upper extremity segmental pressures (arm and forearm) are taken to evaluated ischemia related to atherosclerotic disease. The innominate, subclavian, axillary, brachial, ulnar, and radial arteries are evaluated with duplex/color ultrasound for potential arterial stenosis. If there is suspicion for digital ischemia, a “modified Allen’s test” is performed to assess the completeness of the palmar arches, and digit pressures are evaluated by photoplethysmography.
A pseudoaneurysm, also known as a false aneurysm, is a dilated artery that forms as a result of a leaking hole in an artery. When an artery is injured, blood can leak and pool outside the artery’s wall, most often resulting as complication from cardiac catheterization procedures.
- Painful, tender, pulsatile mass at the site of catheterization or trauma
- Patient history of catheterization or trauma
- Pulsatile mass that is gradually expanding
A pseudoaneurysm evaluation assesses the arteries and veins surrounding catheterization puncture site or trauma site for patency, stenosis, thrombus, hematoma, pseudoaneurysm and AV fistula. The diameter and length of the pseudoaneurysm is measured if present.
Thoracic Outlet Syndrome
Pacific Vascular is often called upon to evaluate changes in arterial blood flow associated with positional changes of the upper extremity related to thoracic outlet syndrome. This syndrome is often suspected in patients with shoulder/arm complaints resulting from occupational repetitive motion traumas, motor vehicle accidents, shoulder or low neck trauma. Although symptoms attributable to this syndrome can occur as a result of arterial compression, it is quite clear that most symptoms are neurogenic in nature due to brachial plexus nerve compression.
- Shoulder/arm numbness and tingling
Continuous wave Doppler is used to take segmental pressures of the upper extremities in order to rule out focal organic obstruction of the arterial circulation. Color Duplex ultrasound is use to evaluate changes in the subclavian artery and vein with arm maneuvers. Photoplethysmography (PPG) at the level of the digits is used to rule out small vessel obstruction by the presence of “fixed” lesions that might result in arterial compromise and provocation of symptoms. With PPG sensors on the digits, changes are noted related to arm elevation maneuvers. The primary purpose of this exam is to provide relevant clinical information, rule out vascular phenomena mimicking TOS, and provide clinical correlates in those situations where arterial compression can be demonstrated with the appropriate symptoms.[/vc_column_text]
Raynaud’s Phenomenon Examination
Raynaud’s phenomenon is defined as episodic digital pallor, cyanosis, or both accompanied by moderate to severe discomfort caused by cold exposure, emotional stress or chronic repetitive trauma to the hand/foot and/or digits. It is believed that the cause is due to an underlying vasospastic condition.
- Digital color changes
- Hand or foot numbness, tingling, pain, and throbbing/burning sensations
- Often the onset is related to cold exposure and/or emotional stress
Predisposing risk factors to Raynaud’s include occupational trauma (repetitive stress to the hand/foot//digits such as when operating a jack hammer), cold injury (frostbite), scleroderma, Rheumatoid Arthritis, Lupus and Berger’s Disease.
A physical exam in our laboratory identifies any diminished wrist or foot pulses or the presence of supraclavicular or femoral bruits. Next, the extremity arterial systems are evaluated segmental pressures including digital measurements with photoplethysmography and spectral analysis. Digital pressures and photoplethysmography are then used to evaluate the digits of the affected limbs in room temperature, ice water immersion, and warm water immersion.
Transcutaneous oxygen pressure (TcPO2) testing evaluates oxygen delivery to tissue, and aids in determining potential success of wound healing, or indication for tissue transfer or revascularization (e.g., bypass grafting) procedure.
To perform a Tcp02 evaluation, the patient remains in the supine position. Small electrodes are placed on standard sites on the chest, below the knee, and two over the dorsum of the foot. An index of the central chest measurement to a regional limb value or a Regional Perfusion Index also contributes to the determination of likelihood of healing.
Radial Artery Mapping
Radial artery mapping is ordered when the radial artery is in consideration for coronary artery bypass graft material. The role of this exam is to evaluate the adequacy of flow to the hand and fingers should the radial artery be removed for use as grafting material.
The radial artery evaluation includes ruling out significant arterial occlusive disease of the upper extremity arterial circulation in general; assessing the completeness of the palmar arches; evaluating dependency of blood flow to the hand on radial versus ulnar arteries; and direct visualization of the radial artery to assess for size, bifurcation level and wall abnormalities.
All studies are performed bilaterally unless otherwise requested.