Absent peripheral pulses

Absent or diminished peripheral pulses are found when a palpable pulse in the upper or lower limb (radial, ulnar, brachial, femoral, popliteal, dorsalis pedis, posterior tibial) cannot be felt. They may reflect acute arterial occlusion, chronic arterial disease, aortic disease, low flow states or normal variation. The first question is whether the limb is acutely threatened.

Clinical relevance. Pulse examination is the simplest screen for peripheral artery disease. About 8% of normal people lack a dorsalis pedis pulse (and 2% a posterior tibial pulse) from congenital variation; absence of both pedal pulses is abnormal. Acute absence with pain, pallor and neurological change is a surgical emergency: limb loss follows within 6 hours without reperfusion.

Classification.

• Acute: embolism (atrial fibrillation, myocardial infarction, valve disease, endocarditis, paradoxical emboli), acute thrombosis in atheroma or aneurysm, aortic dissection, trauma (fracture, dislocation, penetrating injury, iatrogenic after catheterisation), compartment syndrome, thrombosis of graft or stent, vasospasm, cardiac arrest and shock, phlegmasia.
• Chronic: atherosclerosis of aorta, iliac, femoral or tibial arteries, Leriche syndrome, Takayasu arteritis, giant cell arteritis, Buerger disease, radiation arteritis, fibromuscular dysplasia, coarctation of the aorta, popliteal entrapment, subclavian or brachiocephalic stenosis, thoracic outlet syndrome.
• Physiological and non vascular: congenital absence of dorsalis pedis, oedema, obesity, cold limb, hypotension, examiner error, thick skin, ankle swelling.

Related signs. Pulse deficit and delay (radiofemoral delay in coarctation), reduced and delayed pulses (aortic stenosis, pulsus parvus et tardus), unequal pulses (dissection, subclavian steal, embolism), absent pulses with a bruit or aneurysm.

History.

• Onset: sudden (hours) or gradual (months to years), pain, numbness, weakness, coldness, colour change, claudication, rest pain, ulcers.
• Cardiac disease: atrial fibrillation, recent infarction, valve disease, endocarditis, cardiomyopathy, aneurysm, anticoagulation stopped.
• Chest or back pain, tearing pain, syncope (dissection); arm claudication, dizziness with arm use (subclavian steal); neck and arm symptoms (thoracic outlet).
• Trauma, fractures, procedures, arterial puncture, drug injection, cold exposure.
• Vascular risk factors: smoking, diabetes, hypertension, lipids, kidney disease, family history.
• Systemic: fever, weight loss, jaw claudication, headache, visual loss (giant cell arteritis), malaise, arthralgia (Takayasu).
• Drugs: ergots, vasopressors, cocaine, amphetamines.
• Pregnancy and postpartum (spontaneous dissection, thrombosis).

Examination.

• Palpate all pulses and compare sides: radial, brachial, axillary, carotid, femoral, popliteal, dorsalis pedis and posterior tibial; grade 0 (absent), 1 (diminished), 2 (normal), 3 (bounding); use Doppler for absent pulses; check radiofemoral delay.
• Blood pressure in both arms and, if possible, in the legs (difference over 20 mmHg in arms, ankle pressure lower than arm pressure).
• Limb: colour (pallor, mottling, cyanosis), temperature, capillary refill, sensory loss, motor weakness, muscle tenderness and tension, venous filling, skin lesions.
• Bruits (carotid, subclavian, renal, aortic, femoral), aneurysm (abdominal aorta, femoral, popliteal), cardiac rhythm and murmurs, signs of heart failure.
• Look for the six Ps: pain, pallor, pulselessness, paraesthesia, paralysis, perishing cold.
• Signs of aortic dissection: pulse deficit, new aortic regurgitation murmur, neurological signs.
• Signs of vasculitis: tender temporal arteries, bruits, absent pulses, nodules.

Red flags.

• Sudden onset with pain, pallor, paraesthesia or paralysis (acute limb ischaemia).
• Tearing chest or back pain with pulse or blood pressure difference (aortic dissection).
• Hypotension, shock, or cardiac arrest.
• Absent pulses after trauma, fracture, catheterisation or injection.
• Tense, painful compartment, sensory loss, pain on passive stretch.
• Blood pressure difference over 20 mmHg between arms with neurological symptoms.
• Young woman with absent arm pulses, fever, malaise, weight loss (Takayasu arteritis).
• Jaw claudication, scalp tenderness, visual symptoms (giant cell arteritis).
• Pulsatile mass with absent distal pulses.

Acute arterial occlusion. Embolism from the heart (atrial fibrillation, infarct thrombus, vegetation, myxoma), thrombosis of an atherosclerotic or aneurysmal artery, graft occlusion, dissection of the aorta or limb arteries, trauma, iatrogenic injury, compartment syndrome, heparin induced thrombocytopenia with thrombosis, low flow with vasoconstrictor use, popliteal aneurysm thrombosis.

Chronic arterial disease. Atherosclerotic occlusion (aortoiliac, femoropopliteal, tibial), Leriche syndrome, Buerger disease, large vessel vasculitis (Takayasu, giant cell arteritis), radiation arteritis, fibromuscular dysplasia, coarctation of the aorta, subclavian steal, thoracic outlet syndrome, popliteal entrapment, cystic adventitial disease, ergotism, arteriopathy in diabetes with calcification.

Systemic causes. Shock and low cardiac output, hypovolaemia, aortic stenosis, severe heart failure, hypothermia, cardiac tamponade.

Normal or artefactual. Congenital absence of the dorsalis pedis (anatomical variant, often bilateral), oedema, obesity, anxiety and cold hands, examiner inexperience, palpating own pulse.

1. Confirm absence with a hand held Doppler (listen for triphasic, biphasic or monophasic signals); a Doppler signal with normal capillary refill and warmth means the limb is not immediately threatened.
2. Measure ankle brachial pressure index and brachial pressures in both arms; segmental pressures and pulse volume recordings; toe pressures when vessels are calcified.
3. Acute limb ischaemia: do not delay treatment for imaging; start heparin and arrange urgent duplex or CT angiography (or on table angiography) agreed with the vascular surgeon.
4. Blood tests: full blood count, urea, creatinine, electrolytes, creatine kinase, potassium (rhabdomyolysis), lactate, troponin, coagulation screen, glucose, group and save; ESR and C reactive protein for vasculitis; thrombophilia and antiphospholipid screen in young patients; platelet count trend (heparin induced thrombocytopenia).
5. Cardiac evaluation: ECG (atrial fibrillation, infarction), echocardiography (thrombus, vegetation, myxoma, aortic dissection, valve disease), and rhythm monitoring.
6. Aortic imaging for dissection or coarctation: CT aortography (arch to femoral vessels), transoesophageal echocardiography, MR angiography.
7. Chronic: duplex ultrasound, CT or MR angiography for planning; large vessel imaging by MR angiography, CT angiography or PET for Takayasu and giant cell arteritis; temporal artery ultrasound or biopsy.
8. Compartment pressure measurement when compartment syndrome is suspected.
9. Chest radiograph (cervical rib, coarctation notching) and cervical spine films when thoracic outlet syndrome is suspected.
10. Genetic and connective tissue screening in young patients with dissection (Marfan, vascular Ehlers-Danlos).

Limits. Pulses may be impalpable in cold, hypotensive or obese patients despite adequate flow. Calcified vessels give falsely high pressures. Pulses can be present with distal embolic disease (blue toe syndrome). Duplex and CT angiography show anatomy but not tissue viability.

Acute limb ischaemia.

• This is an emergency; call the vascular surgeon at once.
• Unfractionated heparin 5,000 units (70 to 100 units/kg) intravenous bolus, then infusion 18 units/kg/hour adjusting to activated partial thromboplastin time 1.5 to 2.5 times control.
• Give oxygen to keep saturation 94% to 98%, and analgesia (morphine 2.5 to 5 mg intravenously with antiemetic).
• Keep the leg level, warm and padded (do not elevate). Give intravenous fluid, correct potassium and acid base, and check urea, creatinine and creatine kinase for rhabdomyolysis.
• Classify by Rutherford category. Viable: no sensory loss, audible arterial Doppler.
• Marginally threatened: minimal sensory loss, no weakness; salvageable if promptly treated.
• Immediately threatened: sensory loss beyond toes, mild to moderate weakness; salvage with immediate revascularisation.
• Irreversible: profound sensory loss, paralysis, no Doppler signals, rigor; primary amputation.
• Revascularisation: embolectomy with balloon catheter (Fogarty), catheter directed thrombolysis, percutaneous thrombectomy, bypass; fasciotomy for reperfusion compartment syndrome; amputation if non salvageable.
• Catheter directed thrombolysis uses alteplase 0.5 to 1 mg/hour up to 24 to 48 hours. It is contraindicated in recent surgery, bleeding, stroke or neurological compromise needing immediate surgery.
• After revascularisation: lifelong anticoagulation for cardiac embolism (rivaroxaban 20 mg daily, or apixaban 5 mg twice daily, 2.5 mg if two of age 80 or more, weight 60 kg or less, creatinine 133 micromol/L or more; warfarin with INR 2.0 to 3.0 for mechanical valves or mitral stenosis).
• Find and treat the embolic source (atrial fibrillation: rate control and anticoagulation; infarct thrombus; endocarditis: antibiotics; myxoma: surgery). Give antiplatelet and statin for atherosclerosis.
• Monitor for reperfusion injury (hyperkalaemia, myoglobinuria, kidney injury, compartment syndrome). Give sodium bicarbonate and intravenous fluid to keep urine output over 1 mL/kg/hour.
• Heparin induced thrombocytopenia: stop heparin, start argatroban or bivalirudin.

Aortic dissection. Analgesia (morphine 2.5 to 5 mg intravenously), control heart rate under 60 beats/minute with esmolol (500 micrograms/kg bolus then 50 to 300 micrograms/kg/minute) or labetalol, then systolic pressure 100 to 120 mmHg (add nicardipine 5 to 15 mg/hour); emergency surgery for type A or complicated type B (malperfusion with absent pulses: endovascular fenestration or stenting).

Trauma. Realign fractures and dislocations, urgent surgical exploration and repair or shunt, fasciotomy, tetanus prophylaxis, antibiotics.

Compartment syndrome. Remove constrictive dressings, keep the limb at heart level, urgent fasciotomy.

Chronic occlusion. Antiplatelet therapy (aspirin 75 mg or clopidogrel 75 mg daily), atorvastatin 40 to 80 mg daily, smoking cessation, blood pressure under 130/80 mmHg, glucose control, supervised exercise; revascularisation for lifestyle limiting claudication or critical ischaemia.

Large vessel vasculitis.

• Takayasu arteritis: prednisolone 0.5 to 1 mg/kg daily (up to 60 mg) with taper over 6 to 12 months.
• Add methotrexate 15 to 25 mg weekly with folic acid 5 mg weekly, azathioprine 2 mg/kg daily, or tocilizumab 162 mg subcutaneously weekly if relapse.
• Also give aspirin 75 mg daily; angioplasty or bypass in the inactive phase; control hypertension (renal artery stenosis).
• Giant cell arteritis: prednisolone 40 to 60 mg daily started immediately when suspected (do not wait for biopsy; 1 g methylprednisolone intravenously daily for 3 days if visual loss).
• Taper over 12 to 18 months, give aspirin 75 mg and bone protection, and use tocilizumab 162 mg weekly for relapse.

Coarctation of the aorta. Treat hypertension (beta blockers, ACE inhibitors with caution if renal artery involvement), and stent or surgical repair; follow up for re-coarctation, aneurysm and bicuspid aortic valve. Subclavian steal and thoracic outlet syndrome. Angioplasty with stenting or carotid subclavian bypass for symptomatic steal; first rib resection and anticoagulation for vascular thoracic outlet syndrome.

Normal variants. Reassure when absent dorsalis pedis pulse is isolated, with normal posterior tibial pulse, normal Doppler signals and an ankle brachial index of 0.9 or more; no investigation is needed.

Monitoring. In acute ischaemia: neurovascular checks every 15 to 30 minutes, hourly urine output, serial creatine kinase, potassium and creatinine, and compartment checks every 1 to 2 hours for 24 to 48 hours after reperfusion.

In chronic disease: ankle brachial index and duplex every 6 to 12 months, blood pressure in both arms and four limbs, ESR and C reactive protein in vasculitis, imaging every 6 to 12 months in Takayasu arteritis, echocardiography for sources of embolism.

Referral and escalation. Vascular surgery (acute and chronic ischaemia, dissection, aneurysm, trauma, vasculitis surgery), cardiology (embolic source, dissection, coarctation), rheumatology (vasculitis), haematology (thrombophilia, heparin induced thrombocytopenia), critical care (shock), orthopaedic and plastic surgery (trauma), neurology or ophthalmology (giant cell arteritis).

Admission. All acute pulse loss, suspected dissection, trauma, shock, giant cell arteritis with visual symptoms, graft occlusion, and any limb with pain at rest or tissue loss.

Safety netting. Return at once for sudden coldness, pallor, numbness, weakness or severe pain in a limb, tearing chest or back pain, fainting, visual loss, jaw pain on chewing, fever with arm pain, or any new black skin. Take anticoagulants every day without missing doses.

Special groups. Pregnancy and postpartum: spontaneous dissection, embolism from peripartum cardiomyopathy and paradoxical embolism; use heparin (enoxaparin 1 mg/kg twice daily) and avoid warfarin and direct oral anticoagulants. Children: coarctation, Kawasaki disease, trauma and thrombosis from catheters; specialist care. Older adults: atherosclerosis, atrial fibrillation and giant cell arteritis predominate.

Intravenous drug use: septic emboli, pseudoaneurysm and arterial spasm. Endemic regions: rheumatic heart disease with atrial fibrillation, Chagas cardiomyopathy, tuberculous and syphilitic aortitis, Buerger disease, HIV related vasculopathy, and Takayasu arteritis.