THE CONTEXT
Clinical patterns help distinguish peripheral arterial embolism from thrombosis. Upper-limb peripheral arterial disease may also present with digital atheroembolism or subclavian steal.
Onset, severity and distribution
•
Embolism produces complete ischaemia without collaterals and begins over seconds or minutes. Thrombosis produces incomplete ischaemia with collaterals and begins over hours or days.
•
The leg-to-arm ratio is 3:1 for embolism and 10:1 for thrombosis.
•
Multiple sites are involved in up to 15% of embolic cases but rarely in thrombosis.
Distinguishing clinical findings
•
An embolic source, usually atrial fibrillation, is present in embolism and absent in thrombosis.
•
Previous claudication is absent in embolism and present in thrombosis.
•
An embolised artery is soft and tender; a thrombosed artery is hard and calcified.
•
Bruits are absent and contralateral leg pulses are present in embolism. Bruits are present and contralateral leg pulses are absent in thrombosis.
Diagnosis, treatment and prognosis
•
The table lists clinical diagnosis for embolism and angiography for thrombosis.
•
Treatment listed for embolism is embolectomy and warfarin. Treatment listed for thrombosis includes medical therapy, bypass and thrombolysis.
•
In embolism, loss of life exceeds loss of limb; in thrombosis, loss of limb exceeds loss of life.
Upper-limb presentations
•
Subclavian arterial atheroembolism can cause blue fingers because small emboli lodge in digital arteries.
•
Atheroembolic symptoms are typically unilateral, helping distinguish them from the bilateral symptoms described in Raynaud syndrome.
•
Subclavian steal presents with dizziness, cortical blindness or collapse during arm use. It is thought to result from diversion of blood from the brain to the limbs through the vertebral artery.