Systematic Approach to the Peripheral Vascular Exam: Pearls & Pitfalls

Authors: Sophia Gorgens, MD (EM Resident Physician, Northwell NS/LIJ); Jessica Army, MD (EM Attending Physician, Northwell NS/LIJ) // Reviewed by: Marina Boushra, MD; Alex Koyfman, MD (@EMHighAK); Brit Long, MD (@long_brit)

Case

A 62-year-old male with a history of hypertension, congestive heart failure, type II diabetes mellitus, and tobacco use presents to the emergency department (ED) with severe left lower leg pain that started six hours ago. Notably, he works as a long-distance trucker. Vital signs are notable for tachycardia to 116 bpm and a blood pressure of 160/89 mmHg. Upon further questioning, he notes that he was diagnosed with peripheral arterial disease (PAD) a few years ago, but that pain is only present with ambulation. His current pain is worse and present at rest.

• Peripheral arterial disease and its complications
• Deep vein thrombosis or superficial thrombophlebitis
• Diabetic neurovasculopathy
• Compartment syndrome
• Undifferentiated shock
• Trauma

One such systematic approach is to work from the upper extremities to the lower extremities, assessing limb appearance, edema, skin temperature, capillary refill time, and bruits at each level. A useful mnemonic for examination findings is PULSES: ^{1, 3}

Pulses

Ulcers

Looks (appearance of skin and limb, including color, edema, skin thinning)

Skin temperature

Extra time to fill capillary bed

Sound of bruit

1. Pulses—check for presence and strength of all peripheral pulses

This includes radial, brachial, femoral, popliteal, posterior tibial and dorsalis pedis. The strength of the pulse can be characterized as absent, reduced, bounding, or normal.¹

Pearl: The popliteal pulse is notoriously difficult to find.

Pearl: Checking for decreased pedal and tibial pulses and for the presence of femoral bruits has a high specificity for the diagnosis of peripheral arterial disease.^{3, 4}

Pearl: Using the index and third fingers instead of the thumb for palpation improves accuracy and avoids the pitfall of the provider feeling his or her own pulse.

If the pedal or tibial pulses are proving difficult to find, this can be due to anatomical variation. Doppler can be used to find the location of the pulse and direct palpation can then be used to gauge the strength of the pulse and compare it to the contralateral limb.

Pearl: The doppler probe should be held at a 60-degree angle to the skin, pointing towards the flow of blood. Clinicians should avoid applying pressure on the probe as this might block a weak signal.³ Applying extra gel can help to avoid pressure on the area in question.

Pulses are key to a good trauma examination. Although obvious blunt or penetrating trauma easily prompts a vascular exam, knee dislocations—which can be subtle as they may self-reduce—also mandate a thorough vascular exam, especially of peripheral pulses. Knee dislocation or reduction can sever or incarcerate popliteal vasculature. Ultrasound is superior when assessing for vascular damage but not as easy to use or as readily available as doppler. ^{5, 6}

2. Ulcers—are ulcers or gangrene present? If so, what is their type and severity?

Ulcers are usually found on the lower extremities and most can be sorted into the categories of venous, arterial, neurotrophic, lymphatic, malignant, infectious, medication-induced, and inflammatory. The three most common—venous, arterial, and neuropathic—are discussed below.

Venous ulcers (Figure 1) result from poor venous flow and tend to occur on the lateral, medial, and posterior aspects of the leg between the knee and above the ankle. Traditionally, venous ulcers were thought not to be painful unless infected; however, in reality, many patients with uninfected venous ulcers experience pain.⁷

Figure 1: Venous ulcer

Arterial ulcers are from arterial obstruction, are painful, and affect bony pressure points: think heel, shin, or malleoli.

Neuropathic ulcers (Figure 2) most commonly result from the pathologic neurovascular changes associated with diabetes. They are often initiated by casual trauma to the foot (i.e. a small scrape or abrasion) that worsens due to poor wound healing and may become infected.

Figure 2: Neuropathic ulcers

Pearl: Clinicians should review the entire lower extremity carefully—ulcers on the back of the calf or on the sole of the foot can be easily missed.⁸

3. Look—examine the appearance of skin and limb.

Shiny skin can be an indication of PAD. Erythema may be secondary to a number of processes, including cellulitis, general inflammation, or rashes. A pale limb is worrisome for an ischemia.^{3, 9}

Edema is classically seen in the feet and lower legs but can extend past the knee. Unilateral non-pitting edema can be indicative of DVT (may also present as pitting) but may be painless and therefore not always noticed by the patient. Bilateral pitting edema is classically associated with CHF; however, other pathology (cirrhosis, renal failure, venous insufficiency) should be considered.¹⁰

4. Temperature of skin—is it cool or warm?

This can be a clue to poor or inadequate circulation, which can be found in shock, acute limb ischemia, and compartment syndrome.  Comparison with the contralateral extremity can help distinguish individual limb pathology from systemic etiologies.

Pitfall: The traditional 5 Ps (pain, paresthesia, pallor, pulselessness, poikilothermia) are the classically taught signs of ischemia.^{2, 9} Whether in compartment syndrome or arterial occlusion, these are late findings and therefore not helpful in detection early disease.¹¹

Pearl: Pain out of proportion to exam or rapidly increasing pain is one of the earlier and more reliable signs of limb ischemia regardless of etiology.¹¹

5. Capillary refill time—testing for circulation and perfusion.

Press the patient’s nailbed until it turns white, then release and check how long it takes for color to return. Normal capillary refill is 1-2 seconds. A prolonged capillary refill time is indicative of poor perfusion.^3,4,6

6. Bruits-

Listen for femoral and abdominal aortic bruits.^{1, 12}

Pearl: Abdominal bruits are indicative of renal artery stenosis, not abdominal aortic aneurysm.¹²

Pearl: Check the patient’s footwear—having the wrong-sized or -shaped shoes can predispose people with neuropathy to ongoing trauma, especially lacerations that can turn into osteomyelitis if left unchecked.¹³

An ABI is calculated by dividing the ankle systolic pressure by the brachial systolic pressure. To measure the ankle systolic pressure, put a blood pressure cuff on the ankle, find the pedal pulse with a doppler, inflate the cuff and then slowly release until the pedal pulse is heard on doppler.³

Traditionally, an ABI less than 0.9 is concerning for PAD or other causes of arterial occlusion. An ABI less than 0.4 is indicative of critical ischemia.³

Studies vary on reported sensitivity and specificity, but this tool has been used historically and may be requested by consulting services. Knowledge of how to perform the test may benefit the emergency clinician in bolstering an argument for acute limb ischemia; however, the test has not been shown to be predictably superior to the experienced provider’s peripheral vascular exam and pulse palpation, thus a strong clinical suspicion should take priority over a reassuring ABI score.^{3, 4}

Pearl: Ultrasound is helpful. Its particular indications include suspected DVT, venous insufficiency, PAD, and assessment of dialysis access.¹⁴ In diagnosing PAD, one systemic review showed color Doppler ultrasonography has a 90% sensitivity and 99% specificity in diagnosing PAD in a whole-leg exam, though studies vary.^{15, 16}

What about the indications for computed tomography angiography of the limb? CTA has a 95% sensitivity and 96% specificity in patients with >50% occlusion of the artery.¹⁷ In cases of acute limb ischemia, CTA is often first-line over ultrasound, as CTA is not only diagnostic but also crucial for pre-surgical planning and can help determine the exact cause of ischemia.¹⁷ It is also useful in traumatic acute limb ischemia as it allows assessment of nearby soft tissue and bone.¹⁷ The decision whether to acquire a CTA prior to revascularization surgery is often left to the surgeon. In some cases, emergent operation is needed without imaging, whereas in other cases, the ischemia has already reached the point where amputation is necessary and a CTA will be of no benefit.¹⁷

1. For a thorough peripheral vascular exam, check PULSES:

Pulses

Ulcers

Looks (appearance of skin and limb including color, edema, skin thinning)

Skin temperature

Extra time to fill capillary bed

Sound of bruit

2. Review the entire lower extremity carefully and systematically, making sure to check the posterior lower extremity and the heels and soles.

3. Rapidly increasing pain or pain out of proportion to exam are earlier and more reliable findings of limb ischemia than the 5 Ps.

4. Ultrasound is a useful extension of the physical exam, but acute ischemic limb requires a surgery consult and likely a CTA.

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