Chapter 76 - TAAA introduction Flashcards
Frequency of thoracic aortic aneurysms
Ascending 40% Descending 35% Arch 15% Thoracoabdominal 10%
Mean thoracic aortic diameter by anatomic region
Ascending 3cm arch 2.5-3.5 cm descending 2-2.3 cm thoracoabdominal 1.7-2.6 cm
growth rate of TAAA
1.9-3.4 mm/year < 5 cm: 1.7/year > 5cm: 7.9/mm/year rupture > 7 cm/year
male vs female normal thoracic aortic size
2-3 mm bigger in men
Epidemiology of TAAA age and gender
65 years average male 1.7x more 6x more male if age > 75
Percentage of TAAA with first degree relative with aneurysms
20%
Risk factors of TAAA
1) hypertension diastolic > 100 mmhg 2) 20% due to dissection
Percentage of TBAD that required subsequent repair
28-40%
Predictive factor of TBAD needing subsequent repair
initial aortic diameter > 3.5 cm
Protective factor against needing repair after TBAD
false lumen thrombosis at discharge
Rate of reoperation in Marfan patients
20% at 5 years
Mechanisms responsible for familial thoracic aortic aneurysm and dissection
1) TAAD2 (TFGBR2 mutation) 2) 16p (MYH11 gene) 3) TAAD4 (ACTA2 gene) aortic wall building block of actin myosin mutated
5 year survival of a 6cm TAAA and annual rupture risk and annual death risk
54% alive at 5 years 3.7%/year rupture 12%/year death
Risk factors for TAAA rupture
1) COPD 3.6x 2) age 2.6 3) pain 2.3 4) aortic diameter 1.5-1.9x
Estimated annual event rate (rupture or dissection) based on aortic diameter
50mm: < 1% 50-60 mm: 2.7-8.1% > 60 mm: 37.5-62.5% > 80 mm: 80%
Composition difference of ascending vs descending aorta
More elastin in ascending media thicker in ascending
MMPs responsible for TAAA formation
MMP2, MMP9
Causes of TAAA
1) medial degeneration 80% 2) dissection 15-20% 3) connective tissue disorder (MS, EDS, LDS) 4) infection 2% 5) post-op pseudoaneurysm <1% 6) traumatic < 1%
Aortitis that cause TAAA
1) takayasu 2) GCA 3) RA 4) ankylosing spondylitis 5) Reiter syndrome 6) polychondritis
Reiter syndrome triad
Reactive arthritis after UG or GI infection 1) urethritis 2) arthritis 3) conjunctivitis
Crawford classification of TAAA
FIGURE 76.5 TYPE 1: 25% - entire descending + upper AAA TYPE 2: 30% - entire descending and entire AAA TYPE 3: <25% - descending under T6 and entire AAA TYPE 4: < 25% - abdominal visceral and renal arteries TYPE 5: descending under T6 + upper AAA
Physical exam needed for TAAA
1) pressure differential upper and lower 2) visceral ischemia 3) neural deficit 4) murmur of aortic regurg 5) bruits 6) cardiac tamponade
TAAA patients that will also have AAA
20-30%
TAAA region definition
Distal to left subclavian until aortic bifurcation
Synchronous proximal ascending and arch aneurysm in TAAA
6-13%
Marfan with type A dissection, how many will need TAAA repaired subsequently
27% more common in DeBakey I
CXR for diagnosing TAAA
Widened mediastinum in 64-71% specificity of widened mediastinum is 86%
MRI pro/con in TAAA
1) better contrast resolution 2) poorer spatial resolution 3) identifies patency of visceral and renal vessels 4) thrombus and calcium not well displayed
Medical management of TAAA
Extrapolated from ascending or abdominal work 1) BP management with beta blocker + ACEi or ARB 2) smk cessation 3) periodic imaging
BP target in TAAA
< 140/90 diabetes or CKD < 130/80
Betablocker in TAAA
Help marfan to reduce dissection by reducing force of myocardial contraction dP/dt not clear in degenerative TAAA but use anyway
ACEI and ARB in TAAA
Evidence of ARB in reducing reactive oxygen species in marfan patients especially losartan to modulate TGF beta mediated signalling
Statin in TAAA
no clear evidence may reduce NADH/NADPH oxidase and thereby reduce formation of TAAA use anyway for other benefits
Size criteria to indicate elective repair in TAAA
Controversial Guideline: 1) chronic dissection without comorbidity > 5.5 cm for open repair 2) degenerative/traumatic aneurysm > 5.5 cm, saccular or post-op - ENDO 3) end organ failure then treat 4) no ENDO option, high morbidity > 6 cm 5) connective tissue disorder lowers the threshold
Patterson mortality calculation after TEVAR
TABLE 76.9
Preoperative evaluation for TAAA repair
1) Coronary investigation - if severe then treat first (if stable then unclear) 2) PFT, holter, carotid duplex, EEG, neurocognitive test
Coronary revasc before TAAA consideratiosn
1) stenting with DES requires > 6 months of DAPT 2) LIMA not used as it serves as spinal perfusion
Dysphagia lusoria
Dysphagia due to aberrant right subclavian artery
Kommerell diverticulum
aneurysm of the aberrant right subclavian artery
