TAAA Flashcards
What does it mean if the aorta has ectasia? What about aneurysm?
Ectasia: Dilation of the aorta <150% of normal diameter; Aneurysm: >150% of normal diameter (of all 3 layers of the aorta - intima, media, adventia)
What is the difference between an aneurysm and a pseudoaneurysm?
A pseudoaneurysm does NOT involve all 3 layers of the aorta (an aneurysm involves all 3)
What is the cause of dilation of the aorta?
Loss of elastic fibers and increased deposition of proteoglycans (i.e. due to atherosclerosis, fibroelastic diseases, or inflammation of the aorta)
What is the cause of Marfan’s syndrome?
Defect in the FBN1 gene
What system is used to classify aortic aneurysms?
Crawford Classification (different from DeBakey which is for dissections)
What are the various types in the Crawford Classification?
Type I = left subclavian to celiac axis (suprarenal); Type II = left subclavian to the aortic bifurcation (most extensive); Type III = 6th intercostal space to the iliac bifurcation; Type IV = Visceral abdomoinal aorta to the iliac bifurcation (no thoracic component); Type V = 6th intercostal space to above the renal arteries
How many landing zones are there of the aorta?
Eleven
What size aneurysm should you consider surgical intervention?
TAA with diameters >/= 5.5cm OR <5.5cm but risk of rupture OR if there is increased risk for perioperative morbidity and mortality regardless of size
What constitutes increased risk of rupture for TAAs?
Rapid growth >/= 0.5 cm/year + symptomatic aneurysm + connective tissue disease + saccular aneurysm + female + infectious aneurysm
Why is the spinal cord at risk of injury during TAA repairs?
Multifactorial: decreased blood flow due to restriction of segmental arterial inflow + increased tissue pressure from edema or increased ICP + increased venous pressure limiting outflow
What part of the spinal cord is more often damaged?
The anterior spinal cord (versus the posterior) because there is only one anterior spinal artery while there are two posterior spinal arteries
What do you see if you have anterior spinal cord injury?
Decreased motor function
What is the formula for spinal cord perfusion pressure?
SCPP = MAP - ICP; should be > 70mmHg
How far after can you have delayed paraplegia?
Delayed paraplegia can occur any time in the first 2 weeks after open repair (accounts for 60% of spinal cord injuries encountered)
What should you do to optimize spinal cord and end-organ perfusion after open aneurysm repair?
CDV for tachyarrhythmias + increase lumbar drain + increased MAP + transfusion Hbg > 10 g/dL + volume resuscitation
What is the leading cause of morbidity and mortality after TAAA repair?
Respiratory failure
What Crawford classification types require lung isolation?
Type I, Type II, and Type III
What can be damaged during TAAA repair that would affect respiratory function?
The left recurrent laryngeal nerve
What is the perioperative morbidity and mortality rate for an open TAAA repair?
10-15%
What intervention helps reduce postop renal insufficiency?
Delivery of cold crystalloid perfusate into the renal arteries during repair
In what situation are open repairs the recommended route over endovascular?
In patients with connective tissue disorders and aneurysms
What are risk factors for perioperative morbidity and mortality for open surgical repair?
Age >/= 65yo (worse if >/= 75yo) + preoperative renal insufficiency or hemodialysis use + COPD and FEV1 </= 50% predicted + previous stroke
What are risk factors for perioperative morbidity and mortality for TEVAR?
Functional dependence (frailty) + TAAA extent + pulmonary disease + need for iliac access + zone 1/2 landing for thoracic stent graft
What are the different types of endoleaks?
Type I = proximal/distal graft attachment site leaks; Type II = retrograde flow into the aneurysm sac from aortic side branches; Type III = Defect in the graft (i.e. fabric tear or disconnection of modular overlap); Type IV = graft wall porosity; Type V = No identifiable cause
