Aortic Trauma, Dissections, Ulcers Flashcards
What are indications for emergent throacotomy in the setting of trauma?
Shock with penetrating injury, CT output >1500 or >350 cc/hr for 3 hr.
Name 5 exposures and their uses for vascular thorax trauma
1- left anterolateral, most expedient for patients in extremis, can’t access posterior structures 2 - posterolateral - optimal for elective thorax, descending thorax, but often not versatile enough for trauma 3 - sternotomy - access heart/great vessels and is versatile 4 - “trap door” - rarely used because left sided thoracic vessels can be approached with sternotomy extension 5 - Clamshell
What are the 4 grades of BTAI?
1 - intimal tear 2 - intramural hematoma 3 - pseudoaneurysm 4 - free rupture
What are anatomic restrictions that would preclude TEVAR for BTAI
Inadequate seal zone Diseased iliofemoral vessels < 7mm
What type of thoracotomy would you use for a BTAI?
Left posterolateral - gives access to most common site of injury - the isthmus
When performing an open thoracic aortic repair, what is the most expedient way to preserve distal aortic perfusion?
Left heart bypass - cannulation of left inferior pulmonary vein and distal aorta
What is the cut off between “acute”, “subacute” vs “chronic” aortic dissections?
2 weeks - 75% of patients who die from aortic dissections do so in the first 14 days >3 months - chronic, length of time required for flap to become stiff and fibrotic
How frequent are type A vs B dissections?
A - 60% B - 40%
What are 10 risk factors for aortic dissection?
Age, HTN, male, bicuspid aortic valve, annulaortic ectasia, turner, noonan syndrome, arch hypoplasia, Marfan, Ehlers-Danlos, cocaine, pregnancy
Which vessels typically arise from true vs false lumen in type B dissection?
Left renal - false Right renal, SMA, celiac - true
What pathologic vessel wall process is associated with increased risk of aortic dissection?
Medial degeneration - cystic medial necrosis of collagen/elastin in media by elastolysis
Why does the false lumen expand to a larger diameter than the true in a dissection?
Laplace law: wall tension is proportional to vessel radius for a given pressure - wall tension = p x r/w where r = radius of vessel and w = wall thickness. Wall thickness of false lumen lower (only adventitial layer) therefore radius has to grow to accomodate the same wall tension at a given BP. True lumen has most of the elastic components of aortic wall and undergoes radial elastic collapse
What are presenting symptoms of aortic dissection
Pain most common HTN - often refractory Neurologic symptoms - syncope (stretching of baroreceptors in aortic wall cause vasovagal), spinal cord ischemia 10% or type b, parasthesias, hoarseness (compression of recurrent laryngeal), Horner syndrome (compression of sympathetic ganglion) Peripheral Vasc - arch vessels and ilieofem compromise
Why do pleural effusions occur in patients with type b dissection?
Inflammatory reaction of mediastinal pleura
What constitutes standard medical therapy for acute dissection?
Beta blocker and vasodilator (nitroprusside). Beta blocker first because direct vasodilator can have reflex sympathetic stimulation and cause catecholamine release and increase dP/dt
What is the mortality of uncomplicated type b dissection with medical management?
10%
What were the main results of the INSTEAD trial?
No survival advantage of TEVAR over med therapy at 2 years but survival advantage at 5 years on. IRAD data supports this too.
What are hard signs of extremity arterial injury?
Pulsatile bleeding, expanding hematoma, absent distal pulse, thrill/bruit
What are soft signs of arterial extremity injury?
Diminished distal pulse, history of hemorrhage, proximity to named vessel, neurologic deficit
Which imaging modality would you use to evaluate extremity arterial trauma?
CTA, duplex not very useful
Which imaging features suggest an arterial extremity injury can be watched?
No active hemorrhage, no distal ischemia. E.g. intimal tears, pseudoaneurysm, AV fistula
What is the rationale for harvesting the uninjured leg when revascularizing extremity trauma?
Preserve collateral venous drainage (no evidence)
What are 3 ways for getting proximal control in a extremity arterial trauma?
Tourniquet, Cut down proximal vessel (e.g. subclavian, iliac), endovascular placement of occlusion balloon
Why is prosthetic not a good choice in upper extremity arterial trauma?
All wounds considered infected. Also high graft occlusion rate ~5%
