A case of acute limb ischemia due to arterial thrombus formation following trauma

 A 60 year old male patient presented with history of trauma and injury in the posterior aspect of left thigh 6 days back. He developed swelling in this region. Patient also had pain, loss of sensation, absent distal pulse. A clinical diagnosis of compartment syndrome was made.

This was the intraoperatve image of the patient showing swollen lower thigh . Fasciotomy was performed to relieve pressure in the lateral compartment of thigh. Tensor fascia Lata incision was performed to release the pressure in lateral compartment. Vastus lateralis is muscle is seen. There was no clinical improvement following fasciotomy, so further investigations were done 

USG Doppler demonstrate a segment of occlusion by thrombus for 1.2 cm in the distal part of superficial femoral artery. Distal to this site of thrombus no absent arterial flow. The popliteal, anterior tibial, posterior tibial and dorsalis pedis artery are showing monophasic waveform with very low peaksystolic velocity but maintained flow probabaly due to collateral formation. Bilateral lower limb arteries are showing severe atherosclerotic changes

Volume rendering reconstruction of CT angiography demonstrates occlusion of the distal left superficial femoral artery with multiple collateral formation maintaining the distal flow.

CT angiography coronal MIP images of the patient shows segmental occlusion in the distal part of  left superficial femoral artery by thrombus for a 1.1 cm length in the region of adductor canal. However arterial flow is noted distally into the distal part femoral artery, popliteal artery and its branches due to development of multiple collateral vessels. Severe atherosclerotic changes in the arteries explains the development of collaterals. In this case acute thrombus might have developed in a previously atherosclerotic vessel which already had multiple collaterals.

CT axial sections at the level of thigh demonstrates multiloculated collection in the medial aspect of left thigh in the inter muscular plane.

From clinical and radiological evaluation a diagnosis of acute limb ischemia due to thrombus formation following trauma is made.

Acute limb ischemia 

Acute limb ischemia occur when a leg or foot suffers from inadequate blood flow to maintain vital metabolic functions. Both arterial embolism and arterial thrombosis precipitate acute limb ischemia. By convention patient will be presenting with symptoms less than 2 weeks.

It can be due to embolism or thrombosis.

Thrombosis can be due to plaque progression and complication, thrombosis of popliteal artery aneurysm, trauma or graft thrombosis. 

Embolism can be due to cardiac embolization, aortic embolization, thrombosed graft, ergotism, hypercoagulable state, paradoxical venous to arterial embolization, iatrogenic complications related to endovascular procedures.

Clinical features : pain, pallor, parasthesia, pulse deficit and poikilothermia.

The gradual progression of atherosclerosis is frequently accompanied by growth of collateral vessels to distal regions. Acute occlusion in a preconditioned limb may not produce overt ischemia. However propagation of thrombus may induce extensive ischemia. 

Duplex ultrasound: a pre occlusive flow has attenuated systolic peak and absent diastolic flow. Distal to an  occluded segment flow is typically absent. At the site of arterial occlusion a non pulsatile artery without colour flow with a thrombus within the lumen is noted. A well delineated round thrombus in the lumen of artery without significant atherosclerotic burden will be an embolism thrombus.

Other investigations : CT angiography, Gd enhanced mr angiography, DSA