B P5 C42 Diseases of the Aorta Flashcards
Begins at the aortic valve and extends to the sinotubular junction. This supports the bases of the aortic valve leaflets.
Aortic root
The right and left coronary arteries arise from the __________________
Sinuses of Valsalva
Begins at the sinotubular junction and rises to join the aortic arch. The proximal portion of the ascending aorta lies within the pericardial cavity, anterior to the pulmonary artery bifurcation
Upper portion of the ascending aorta
Gives rise to the innominate artery, the left common carotid artery, and the left subclavian artery.
Aortic arch
Begins distal to the left subclavian artery.
Descending thoracic aorta
Marks the point at which the aortic arch joins the descending aorta
Ligamentum arteriosum
Marks the site of transition between the relatively mobile ascending aorta and the fixed descending aorta making it vulnerable to deceleration trauma.
Aortic isthmus
Gives rise to the celiac artery and the superior mesenteric artery anteriorly, followed by the posterolateral origins of the left and anterolateral right renal arteries.
Abdominal aorta
This segment of the aorta is called the suprarenal or visceral segment. The infrarenal aorta lies anterior to the lumbar spine, where paired lumbar artery branches arise posteriorly.
The aorta ends by bifurcation into _________________
Common iliac arteries
In the proximal aortic segments, the vasa vasorum supply additional nutrients to the outer third of the thoracic aortic media. The ____________ aorta normally lacks an independent microvascular supply.
Infrarenal
The aortic wall pressure-diameter relationship is nonlinear; a more distensible component is demonstrated at lower pressures and a stiffer component at higher pressures, with the transition from distensible to stiff behavior occurring at pressures higher than _________________
80 mm Hg
Aortic diameter is generally less than __________________ at the root and becomes smaller distally.
< 40 mm
The bifurcation typically occurs at the level of the umbilicus and the _______________
L4 vertebral body.
refers to a pathologic segment of aortic d tation that expands and can eventually rupture or dissect. One criterion for abnormal aortic dilatation is a diameter of at least 50% greater than expected for the same aortic segment or l dilation 50% greater than the adjacent normal aorta
Aortic aneurysm
The more common type, are symmetrically dilated with involvement of the entire aortic circumference
Fusiform
Exhubits focal outpouching. These both are “true” aneurysms with an intact aortic wall involving all layers.
Saccular
Bleeding has occurred through the aortic wall r ing in a contained periaortic hematoma in continuity with the aortic lumen; may result from trauma, infection or contained rupture of an aortic aneurysm, dissection, or penetrating ulcer.
Pseudoaneuyrsm
Defined by an abdominal aorta greater than 3.0 cm in diameter
AAA
The most common form of aortic aneurysms, being present in 2.3% of those 75 to 79 years old.
AAA
Most AAA (>80%) arise in the ______________
Infrarenal aorta
AAAs are approximately five times more prevalent in _____ than in women, and are associated strongly with age, with most occurring in those ______________ and even higher risk in those older than 75 years.
Men
>60 years
AAAs strongly are associated with ______________
Cigarette smoking
Current smokers are seven times more likely to have an AAA than nonsmokers with duration and quantity of smoking increasing risk. Smoking also increases AAA growth rate. Other risk factors include emphysema, hypertension, and hyperlipidemia.
A family history is a potent risk factor for AAA being present in about 20%
Matrix-degrading enzymes released by inflammatory cells lead to ___________________ and play a role in dilation and rupture.
Medial degeneration
AAA formation associates with chronic aortic wall inflammation, increased local expression of proteinases, and degradation of structural connective tissue proteins
Enzymes including ____________________ and elastolytic cathepsins degrade arterial matrix constituents contributing to aneurysm expansion and rupture.
Matrix metalloproteinases (MMPs)
In the absence of vasa vasorum, the nutrient supply to the media of the distal aorta depends on __________________, which may be jeopardized by intimal thickening and atherosclerotic plaque.
Diffusion from the lumen
Only ___________ of AAAs are noted on physical examination, although aneurysms larger than 5 cm can be detected in approximately 75% of patients, depending on body habitus
30% to 40%
Patients with AAA may have coexisting ________ (25%) and have an increased prevalence of iliac and popliteal aneurysms
TAA disease
_________________ can detect AAAs with high accuracy and is preferred over CT in screening for AAAs
Abdominal ultrasound
________________ is more accurate than ultrasound; especially useful in demonstrating the relationship of the AAA to the renal, visceral, and iliac arteries and patterns of mural thrombus, calcification, or coexisting occlusive atherosclerosis; useful for follow up in larger AAA
CT angiography (CTA)
The U.S. Preventive Services Task Force recommends a one-time ultrasound screening for AAAs in ____________________ and selective screening for those who never smoked
Men 65 to 75 years of age with a history of smoking
The Society for Vascular Surgery (SVS) recommends a one-time screening for AAAs in _________________ of AAAs.
All men ≥65 years and for women ≥65 years with a history of tobacco use or a family history
The Centers for Medicare and Medicaid Services will currently reimburse screening for ________________ of AAA.
Men 65 to 75 who ever smoked and men and women 65 to 75 with a family history
AAAs expand gradually and variably with an average growth rate of ___________________ per year and larger aortas grow more rapidly
2.2 mm (range 1 to 5 mm) per year
AAA ___________ is most important in predicting rupture
Diameter
The ________________ may predict risk better in women.
Aortic size indexed to body size
Factors associated with risk of AAA rupture include
Current smoking
Female gender
Emphysema
Hypertension
Immunotherapy after organ transplantation
Repair should be considered for asymptomatic aneurysms greater than
5.0 to 5.5 cm in diameter
Symptomatic aneurysms and those with rapid growth (_________) require more urgent consideration.
> 1 cm/year
AAA repair at smaller size (closer to ___________) should be considered for women due to increased risk of rupture.
5 cm
In patients with AAAs larger than 4.5 cm, _________ is preferred over ultrasound for more accurate measurement.
CT
The following surveillance imaging strategy for AAAs of various sizes has been proposed:
2.5 to 2.9 cm
3.0 to 3.9 cm
4.0 to 4.9 cm
5.0 to 5.4 cm
2.5 to 2.9 cm, every 7 years
3.0 to 3.9 cm, every 3 years
4.0 to 4.9 cm, every 1 year
5.0 to 5.4 cm, every 3 to 6 months
True or False
Patients with small AAAs should exercise regularly because moderate physical activity does not adversely influence the risk for rupture and may limit AAA growth.
True
AAA repair is recommended when the diameter exceeds _______ with earlier repair considered for those with rapid expansion, young age, and in women.
5.4 cm
AAA is treated surgically by either open surgical repair (OSR) or EVAR, with _______ associated with a threefold less perioperative mortality
EVAR (1.5% with EVAR vs. 4.2% to 5.2% for OSR)
Perioperative medical management to reduce cardiac risk may include continuation of beta blockers, statins, and/or aspirin.
Selection of the approach depends on the AAA anatomy, age, and risks associated with anesthesia and surgery,
Late complications develop in as many as _______ of patients after OSR for AAAs, including hernia and bowel obstruction, perianastomotic aneurysms (including pseudoaneurysms at suture lines and true aneurysms proximally), graft infection, graft-enteric fistula, and graft limb occlusions with lower extremity ischemia.
15% to 30%
OSR for AAAs should optimally be performed at centers with demonstrable operative mortality rates lower than 5%
After OSR patients should generally have annual clinical follow-up with CT at 5-year intervals, or more frequently if there are small aneurysms in adjacent vessels
In patients with suitable anatomy, EVAR offers a less invasive alternative to OSR. EVAR requires adequate ________________ attachment sites.
Nonaneurysmal proximal and distal
Long-term, multicenter, randomized, controlled trial comparing open repair with endovascular repair in 351 patients with an abdominal aortic aneurysm of at least 5 cm in diameter who were considered suitable candidates for both techniques. The primary outcomes were rates of death from any cause and reintervention
Six years after randomization, endovascular and open repair of abdominal aortic aneurysm resulted in similar rates of survival. The rate of secondary interventions was significantly higher for endovascular repair.
DREAM trial (Long-Term Outcome of Open or Endovascular Repair of Abdominal Aortic Aneurysm)
Long-term, multicenter, randomized, controlled trial comparing open repair with endovascular repair in 351 patients with an abdominal aortic aneurysm of at least 5 cm in diameter who were considered suitable candidates for both techniques. The primary outcomes were rates of death from any cause and reintervention
Six years after randomization, endovascular and open repair of abdominal aortic aneurysm resulted in similar rates of survival. The rate of secondary interventions was significantly higher for endovascular repair.
DREAM trial (Long-Term Outcome of Open or Endovascular Repair of Abdominal Aortic Aneurysm)
Randomly assigned 1252 patients with large abdominal aortic aneurysms (≥5.5 cm in diameter) to undergo either endovascular or open repair; 626 patients were assigned to each group. Patients were followed for rates of death, graft-related complications, reinterventions, and resource use until the end of 2009
Endovascular repair of abdominal aortic aneurysm was associated with a significantly lower operative mortality than open surgical repair. However, no differences were seen in total mortality or aneurysm-related mortality in the long term. Endovascular repair was associated with increased rates of graft-related complications and reinterventions and was more costly
EVAR-1 trial (Endovascular versus Open Repair of Abdominal Aortic Aneurysm)
It is reasonable to consider an ________ first strategy for younger, low-risk patients with long life expectancy.
OSR
Persistent blood flow in the aneurysm sac outside the endograft) develop in almost 25% of patients at follow-up with many requiring subsequent therapy
Endoleaks
The most common endoleak, result from retrograde filling of the aneurysm sac by aortic branch vessels, usually by the lumbar or inferior mesenteric arteries
Type II
Types of endoleaks and treatment
loss of complete sealing at the proximal or end of the stent graft, lead to increased pressure in the aneurysm sac and are associated with increased risk for rupture and therefore warrant repair
Type I
Caused by separation of components or disruption of the endograft fabric and require treatment, usually by re-lining with a stent graft.
Type III
Endoleaks are related to blood seeping through porous graft material and are self-limited.
Type IV
An enlarging AAA after EVAR without a demonstrated endoleak and with a diameter increased to greater than 10 mm, usually requires repair
Type V
Imaging with contrast-enhanced CTA is typically performed at ____________ after implantation of the device.
One month and annually
Aortic diameters ____________ in adults generally considered to be enlarged.
Greater than 40 mm
Prolonged _____________ exercise is associated with an increased prevalence of ascending aortic dilatation.
Endurance exercise
Most common (approximately 60%) of TAA
Aortic root or ascending aortic aneurysms
Followed by aneurysms of the descending aorta (approximately 35%) and aortic arch (<10%)
_______________ (approximately 10%) refers to descending thoracic aneurysms that extend distally to involve the abdominal aorta.
Thoracoabdominal aortic aneurysm
Many of the heritable disorders preferentially involve the ___________________, but some may involve the arch and descending aorta.
Aortic root and ascending aorta
Causes of TAAs include heritable disorders, congenital disorders, degenerative (atherosclerotic), mechanical,inflammatory,and infectious diseases.
Up to _______ of patients with AAA have either synchronous or metachronous TAA.
25%
__________ describes degeneration and fragmentation of elastic fibers, loss of SMCs, increase in deposition of collagen, and interstitial “cysts” of mucoid-appearing basophilic-staining extracellular matrix
Cystic medial degeneration (CMD)
Syndromic HTADs
MFS
LDS
vEDS
Nonsyndromic HTADs (also called familial TAA disorders) are due to mutations in multiple genes. 7 Up to 20% of individuals with a TAA will have a family history of TAA or will have an affected first-degree relative.
Give the corresponding gene affected
Marfan Syndrome
Loeys-Dietz Syndrome
Vascular EDS
Marfan Syndrome - FBN1
Loeys-Dietz Syndrome - TGFBR1, TGFBR2
Vascular EDS - COL3A1
MFS, an autosomal dominant disorder of connective tissue, results from abnormal fibrillin-1 due to mutations in the FBN1 gene.
Aortic dilation in MFS affects most prominently the _________________
Sinuses of Valsalva
____________ is the major component of the microfibril, a primary component of the extracellular matrix, and by interaction with lysyl oxidase (encoded by LOX), promotes vascular SMC adhesion and elastin support.
Fibrillin-1
___________mutations in multiple genes in the TGF-β signaling pathway, leads to craniofacial abnormalities (hypertelorism, bifid/broad uvula, cleft palate, craniosynostosis), arterial tortuosity, and aneurysms and dissections of the aorta and branch vessels. Cutaneous features include easy bruisability, visible veins, widened scars, and facial milia.
Loeys-Dietz Syndrome
___________ may have a more aggressive phenotype than TGFBR1 mutations and aortic surgery is recommended at aortic root dimensions of 4 to 4.5 cm.
TGFBR2 mutations
___________ due to SMAD3 mutations, involves severe osteoarthritis and osteochondritis dissecans, in addition to the vascular, skeletal, and cutaneous features of LDS and may merit aortic surgery at relatively small aortic root diameters and mutations in TGFB2 share features of MFS and LDS.
Aneurysms-osteoarthritis syndrome (AOS or LDS3)
____________ due to mutations in COL3A1 causing abnormal type III procollagen synthesis, associates with aortic and branch vessel aneurysm, rupture, and/or dissection and rupture of visceral organs at a young age leading to reduced lifespan
vEDS
Aortic root disease is less common in vEDS, with more frequent involvement of the _________________
Descending and abdominal aorta and branch vessel
Individuals with vEDS have risk for spontaneous arterial dissection and rupture, often involving medium-sized arteries that did not exhibit significant dilation.
_______________ are inherited as an autosomal dominant trait with decreased penetrance and variable expression (especially in women) and are more common than syndromic aortopathies.
Nonsyndromic HTADs (familial TAA)
__________ affects 1% of the population, associates with ascending aortic aneurysm, coarctation of the aorta, and aortic dissection
BAV
____________ due to helical flow patterns in the setting of BAVs may underlie the aortopathy of BAV disease
Abnormal aortic wall shear stress
The BAV exhibits abnormal leaflet folding, wrinkling, and increased leaflet doming, which can result in turbulence even in the absence of a stenotic or regurgitant lesion.
The aortic dilatation in BAV disease occurs most often in the ___________
Proximal to mid-ascending aorta
Ascending TAAs a ated with BAVs may develop independent of valve function and may develop late after aortic valve replacement (AVR).
________ underlies the aortic aneurysm and risk for dissection associated with BAVs.
CMD
When BAV and TAA coexist, CMD is more pronounced in ____________ than stenotic BAV.
Regurgitant
The lifetime risk of aortic dissection for the BAV patient is ____________ higher than the risk in the general population, but the absolute risk is very low unless aortic aneurysm is present.
4 to 8 times
____________ results from complete or partial loss of a second sex chromosome (XO, Xp)
Turner Syndrome
Patients with TS have an estimated ______________ for aortic dissection than do age-matched controls
100-fold greater risk
Women with TS but without risk factors for aortic dissection should undergo reevaluation of the aorta every _____________ or when clinically indicated (such as when contemplating pregnancy).
5 to 10 years
Most women with TS who suffer aortic d tion have risk factors, including aortic dilatation, BAV, coarctation of the aorta, or hypertension
TS patients have increased aortic diameter relative to body surface area and a higher risk for dissection at ________________.
smaller absolute aortic diameters
Degenerative TAAs occur most commonly in the _____________, have a _______ predominance (1.7 to 1), present at an average age of ________, and are associated with aortic __________________.
Descending aorta
Male
65 years
Atherosclerosis
These aneurysms tend to originate just distal to the origin of the left subclavian artery, may be either fusiform or saccular, and may extend into the abdominal aorta or coexist with AAAs.
Aneurysm formation develops during the chronic stage of dissection, being most common in the ________________
Proximal descending aorta
____________ the embryologic remnant located at the origin of an aberrant subclavian artery that may lead to aneurysmal dilatation, rupture, or aortic dissection.
Kommerell diverticulum
Surgical intervention is considered when the diverticulum diameter exceeds ________ and/or the diameter of the descending aorta adjacent to the diverticulum exceeds ___________
30 mm
50 to 55 mm.
Cardiovascular syphilis occurs in the tertiary stage and typically involves the _________________
Ascending aorta and arch
Pathologic features include lymphocytic and plasma cell inflammation in the adventitia, with the classic appearance of a “tree bark” or wrinkled appearance of the aortic intima.
Tertiary syphilis may cause aortic valvulitis, aortic regurgitation (AR), and coronary ostial stenosis.
Symptoms of TAAs usually relate to
Local mass effect
Progressive AR
Systemic embolization due to mural thrombus or atheroembolism
Eelated to acute dissection or rupture
Obstruction of the superior vena cava or innominate vein may result from ascending aorta or arch aneurysms. TAAs may compress the trachea, bronchus, or esophagus or lead to hoarseness from __________________
Laryngeal nerve compression
Persistent chest or back pain may occur because of a direct mass effect from the TAA, with compression of intrathoracic structures or erosion into bones. The most serious complications
The most serious complications of TAAs are _________________
Rupture and dissection
Aortic rupture leads to sudden severe chest or back pain.
Rupture into the pleural cavity (usually ______) or into the mediastinum is associated with hypotension, rupture into the esophagus leads to hematemesis, and rupture into the bronchus or trachea leads to hemoptysis.
Left
_____________ are associated with pain, fever, and fistulas.
Acute aortic expansion, contained rupture, and pseudoaneurysm can cause chest or back pain.
Infected TAAs
Some TAAs are evident on chest x-rays with features including
Widened mediastinum
Prominent aortic knob
Displaced trachea
_________________ provide outstanding detail of aortic and branch vessel anatomy in TAA disease
Contrast-enhanced CT and MRA
Multidetector CTA and MRA allow r tion of the axial data into three-dimensional images, permitting aortic measurement in a double oblique technique to obtain an accurate diameter
TAAs are relatively indolent, with a growth rate of approximately ______________ and marked individual variability.
1 to 2 mm/year
Rupture and acute dissection are the major complications of TAAs. Less than half of patients with rupture arrive at the hospital alive; mortality at 24 hours reaches ______
75%
The risk of aortic dissection, rupture, and death increases with enlarging aortic diameters with “hinge points” at
aortic diameters greater than ______________ for ascending aortic aneurysms and ____________ for descending aortic aneurysms
> 5.25 to 5.75 cm - ascending
Above 6.0 cm - descending
_______________ is the most important risk factor for aneurysm complications, but other factors influence this risk including sex, body surface area and height, and indexing of aortic size in certain populations may inform risk.
Aortic diameter
Size Threshold for Prophylactic Aortic Root or Ascending Aortic Aneurysm Resection for Various Conditions
Degenerative aneurysm
BAV
BAV with risk factors or low surgical risk
BAV requiring AVR
MFS
MFS with risk factors
LDS
Familial thoracic aortic aneurysm
Turner syndrome
Degenerative aneurysm - >/= 5.5
BAV - >/= 5.5
BAV with risk factors or low surgical risk - >/= 5.0
BAV requiring AVR - >/= 4.5
MFS - >/= 5.0
MFS with risk factors - >/= 4.5
LDS - 4.0 - 4.5
Familial thoracic aortic aneurysm - 4.5 - 5.0
Turner syndrome - >2.5cm/m2
Identify the ffg aortic landmarks
Treatment of ascending TAAs involves opening the ascending aorta and placement of a prosthetic graft with or without concomitant AVR.
A composite graft consisting of a Dacron tube with a prosthetic aortic valve sewn into one end (the _______________________) is generally the method of choice in treating ascending TAAs involving the root and associated with significant aortic valve disease.
Modified Bentall procedure
The valve and graft are sewn directly into the aortic annulus, and the coronary arteries are reimplanted into the Dacron graft.
Patients with structurally normal aortic valve leaflets and those whose AR is secondary to dilation of the sinotubular junction or aortic annulus may be able to undergo a valve-sparing root replacement—reimplanting the native valve within a Dacron graft ( _____________) or by remodeling the aortic root ( _____________ )
David procedure
Yacoub procedure
The reimplantation technique is preferable to the remodeling technique (especially in genetic aortopathy) because it stabilizes the annulus and limits aortic dilation and late AR
A pulmonary autograft (the _______________) is an alternative to a composite aortic graft in appropriate candidates.
Ross procedure
This procedure involves replacing the native aortic valve and root with the patient’s own pulmonary root, inserted into the aortic position. The pulmonary root is replaced with a cryopreserved homograft root.
The Ross procedure carries risks of late autograft ______________ and should not be used in patients with genetically triggered aortic root diseases.
Aneurysm formation
Aortic arch aneurysms are more difficult to treat surgically because reconstruction of the aortic arch vessels requires interruption of blood flow to these vessels
One approach uses a ______________—the arch vessels remain intact, with the upper aortic arch as a roof, and the remaining arch is replaced.
_________________ requires either removing the entire arch and using branched grafts to replace the arch and great vessels, by using bypasses constructed to each great vessel, or less often reimplanting an island of arch tissue that includes the origins of the great vessels
Hemiarch resection
Extended arch resection
A modification of this procedure uses a c ered endovascular stent graft attached to a vascular graft to allow fixation of the stent graft within the descending aorta and vascular graft reconstruction of the aortic arch
This _____________ procedure allows total replacement of the arch and descending aorta in a single stage for complex aneurysms and also the treatment of acute type A dissection
“frozen elephant trunk”
Because the aortic disease often extends distally, the polyester graft can be extended as an elephant trunk into the descending aorta, and necessitates a second procedure to complete the repair. In this procedure, the distal anastomosis is created to the midportion of a graft and the distal graft is within the lumen of the aorta and thus can be retrieved without manipulation of the arch. A
______________ occurs in 5% to 9% of frozen elephant trunk procedures.
Arch aneurysm surgery has a morbidity and mortality rate of _______ risk for both death and stroke.
Spinal cord injury
2% to 7%
Descending TA
The European Society for Vascular Surgery Guidelines recommend that repair should be considered when descending TAA reaches ________ and may be considered for aneurysms of 56 to 59 mm, with lower thresholds to be considered in _______________
60 mm
Women and in those with heritable aortic disease
The Society for Vascular Surgery Guidelines recommend TEVAR for _______ individuals with descending TAA diameter greater than ________
Low-risk
55 mm
TEVAR are associated with a perioperative mortality of 10% (5% to 22%) and a paraplegia rate of approximately ___________
2% to 6%
Describes the extent of the aneurysm, and this predicts morbidity, mortality, and risk for paralysis with repair
Crawford Classification
Because of the risk of the p dure, in general, surgical repair is considered for ___________ patients with TAAA greater than ______ (less for those with heritable aortic disease, rapid growth [>10 mm/year], or with symptoms)
Low- to moderate-risk
60 mm
Involves the entire thoracic aorta and the upper a inal aorta extending from the proximal descending aorta above the T6 vertebra to the level of the renal arteries (approximately 25 of TAAAs
Type I
The highest-risk group, with the aneurysm involving the entire thoracic and most or all of the abdominal aorta extending from the proximal descending aorta above T6 to below the renal arteries, often to the iliac bifurcation (30% of TAAAs)
Type II
Involve the distal half of the descending thoracic aorta below T6 and extend into the abdominal aorta (<25% of TAAAs)
Type III
Extends from the diaphragm and involves most of the abdominal aorta to the aortic bifurcation (<25% of TAAAs
Type IV
Distal half of the descending aorta (below T6) and extend into the abdominal aorta, but are limited to the visceral segment.
Type V
TEVAR, a far less invasive alternative to OSR of descending TAAs, has lower morbidity and mortality rates than OSR and is preferable when feasible.
For TEVAR, the aorta must have adequate proximal and distal landing zones of at least ________P_ in length and diameters that accommodate the endograft and adequate vascular access.
20 to 25 mm
TEVAR for descending TAA has a lower 30-day mortality rate than OSR (5.6% vs. 17%) and a lower risk of ______________
Stroke risk in TEVAR for TAA disease is 3% to 6%.
Stroke and paraplegia
Transposition of the ______________ or a left carotid-to-subclavian bypass is recommended before TEVAR when covering the left subclavian is required to lessen ischemic risk
Left subclavian artery
_______________ with the development of paraparesis or paraplegia is a major source of morbidity
Spinal cord dysfunction
Drainage of cerebrospinal fluid has been used in combination with a mean arterial pressure of at least ___________ (>90 mm Hg in those at high risk) to lessen spinal cord complications
70 mm Hg
Placement of a spinal drain is also associated with complications and routine use is typically not recommended unless there are risk factors such as
Coverage greater than 15 cm of descending thoracic aorta
Loss of the left subclavian, hypogastric, or lumbar arteries from prior or concomitant aortic surgery or occlusive disease
_____________ are the most common complication of endovascular repairs and occur in 10% to 20% of patients
Endoleaks
Recommended timing of surveillance imaging for
Degenerative TAA 4.0 - 4.5 cm
Degenerative TAA 4.5 - 5.4 cm
Small TAA
MFS and familial TAAD 3.5 - 4.4 cm
MFS and familial TAAD 4.5 - 5.0 cm
BAV with aortic dilatation
Degenerative TAA 4.0 - 4.5 cm - Annual
Degenerative TAA 4.5 - 5.4 cm - 612 months
Small TAA - 2.-3 years
MFS and familial TAAD 3.5 - 4.4 cm - Annual
MFS and familial TAAD 4.5 - 5.0 cm - Annual or Biannual
BAV with aortic dilatation - Annual
Aortic events have been associated with _______________ use and avoidance of this antibiotic class is recommended for those with or at risk for aneurysm disease.
Fluoroquinolone
Avoidance of strenuous physical activity, especially ___________
Isometric exercise and weightlifting
Include aortic dissection, aortic intramural hematoma (IMH), and penetrating atherosclerotic aortic ulcer (PAU)
Acute aortic syndromes
In 80% to 90% of acute aortic syndromes, ___________ is present, with intimal disruption leading to a dissection plane in the media that may propagate anterograde
Aortic dissection
In aortic dissection, an intimal flap exists between the two lumens (true and false lumens).
Ten to 20% of acute aortic syndromes result from ________, where bleeding in the aortic wall occurs without imaging evidence of an intimal tear or dissection flap
IMH
_________ also lead to acute aortic syndromes in approximately 5% of cases.
PAUs
Two thirds of aortic dissections occur in _______
Acute aortic dissection has a very high early mortality, with up to a _______death rate
Men
1% per hour after type A dissection
_____________ occurs most commonly in individuals between 50 and 60 years of age
_____________ at a peak of 60 to 70 years of age.
Women present at older ages than men
Type A aortic dissection
Type B dissection
The main hypothesis for acute aortic dissection is a primary entry tear in the ____________ with blood penetrating into the diseased media and leading to propagation of the dissection and creation of the true and false lumens.
Aortic intima
Primary rupture of the vasa vasorum with r tant intimal disruption is a second hypothesis.
Distention of the false lumen with blood causes the intimal flap to compress the true lumen and narrow its caliber and may lead to __________________
Malperfusion syndromes
Give the classification of dissection
Originates in the ascending aorta and extends at least to the aortic arch and typically to the descending aorta (and beyond)
Stanford A Debakey I
Identify
Stanford B Debakey III
Most type A dissections begin within a few centimeters of the aortic valve, and most type B dissections begin just distal to the left subclavian artery.
Approximately 65% of intimal tears occur in the ascending aorta, 30% in the descending aorta, less than 10% in the aortic arch, and approximately 1% in the abdominal aorta.
Entry tear originates only in the ascending aorta (zone 0)
Type A
Cut offs for the Classical definition of Duration of dissection from symptom onset
Acute: < 14 days
Chronic : > 14 days
Several conditions predispose the aorta to dissection, most due to _________________ or _________________.
Some 75% of all patients with aortic dissection have __________
Disruption of the integrity of the aortic wall
Marked increases in aortic wall circumferential stress
Hypertension
In the IRAD, conditions associated with dissection included: hypertension (77%), atherosclerosis (27%), previous cardiac surgery (16%), known aortic aneurysm (16%), MFS (5%), iatrogenic (3%), and cocaine use
Type B dissection may also complicate HTAD, may be the first presentation of the disease, and is more common after _______________
Prior root replacement
________ is an important risk factor for ascending aortic aneurysm and dissection
BAV
Cocaine-related aortic dissection is more commonly _________, often presenting with hypertension and small aortic diameters.
Type B
Women with ________________ have increased risk for acute aortic dissection related to pregnancy.
MFS, LDS, nonsyndromic HTAD, vEDS, TS, and BAV with aneurysm
Individuals with TAA have risk for aortic dissection, with higher risk for dissection and rupture as aortic size increases.
True or False
However, many aortic dissections occur in patients with aortic dimensions that are not markedly dilated and are below thresholds for prophylactic aortic repair.
_____________ is the most classic feature.
Abrupt onset of severe chest or back pain
Distinct from the discomfort of coronary ischemia, the pain is described as severe in approximately 90% of patients and usually of sudden onset, with maximum intensity occurring at its inception.
Some patients describe a “sense of doom.” The pain quality is most often described as “sharp,” “severe,” or “stabbing,” and descriptors such as “tearing” or “ripping” are less common.
Acute CHF related to type A dissection may result from ___________
__________ in patients with type A dissection usually associates with hemopericardium, rupture, arch vessel involvement, or stroke.
Syncope
_______________ occurs in 6% of patients and associates with syncope, stroke, previous aortic aneurysm, and prior cardiac surgery.
“Painless” aortic dissection
Other clinical features at presentation include congestive heart failure (CHF) (<10%), syncope (9%), acute stroke (6%), acute MI, paraplegia, and cardiac arrest or sudden death.
A ___________ is reported in 30% of type A dissections and 20% of type B dissections with frank limb ischemia less common.
Malperfusion, occurring in up to 30%, is the most common _________, but may be static or mixed.
Pulse deficit
Dynamic
_________________ results from the pressurized false lumen pushing the septum toward the true lumen leading to collapse of the true lumen, obstructing branch vessels.
Dynamic malperfusion
_____________ results from stenosis or occlusion of a branch artery due to the dissection flap, hematoma, embolism, or thrombosis
Static malperfusion
__________ occurs in 41% to 76% of patients with type A dissection, with a diastolic murmur audible in 40%
Aortic regurgitation
Mechanisms of AR relate to the functional aortic annulus and aortic valve and may be due to
Acute dilation of the aortic sinuses and/or sinotubular junction, commissural disruption
Restrictive cusp mobility
Aortic leaflet prolapse
Circumferential dehiscing intimal flap prolapsing into the left ventricular outflow tract during diastole interfering with valve coaptation
Preexisting AR due to a preexisting aortic root aneurysm or BAV
______________ occur in 15% to 40% of patients with aortic dissection and are more common with type A dissections.
Neurologic manifestations
Neurologic syndromes include persistent or transient ischemic stroke, spinal cord ischemia, ischemic neuropathy, and hypoxic encephalopathy and are related to malperfusion of one or more branches supplying the brain, spinal cord, or peripheral nerves
Coronary ischemia is present in 5% to 10% of patients with type A dissection and ST-segment elevation myocardial infarction (STEMI) occurs in approximately 2% (most commonly affecting the ___________)
Right coronary artery
Coronary malperfusion may be due to the false lumen involving the coronary ostium, dissection flap extending into the coronary, or avulsion of the coronary artery
Renal artery involvement occurs in at least 5% to 10% of patients and may lead to ______________________
Renal ischemia, infarction, or renal insufficiency or refractory hypertension
_________________ occurs in less than 5% of dissection and associates with a marked increase in mortality.
Mesenteric ischemia
Aortic dissection may lead to a ______________ bland or inflammatory pleural effusion, but hemothorax may occur from aortic rupture.
Left-sided
The most common abnormalities are _______________________, appearing in approximately 70% to 80% of cases
(83% of type A; 72% of type B).
Abnormal aortic contour or widening of the aortic silhouette
Patients with acute aortic dissection have elevated _________ levels making this a very useful biomarker for classic acute dissection
D-dimer
In patients seen within the first 24 hours of onset, a D-dimer level lower than 500 ng/mL had a negative likelihood ratio of 0.07 and a negative predictive value of 95%. D-dimer is reported as having a sensitivity of 97% and a specificity of 47%. 1 , 41 Notably, normal D-dimer levels can occur with aortic dissection and a thrombosed false lumen, as well as with aortic IMH and PAU
The modality most commonly used for evaluating aortic dissection and is best performed with an ECG-gated, multidetector scanner, which may eliminate aortic pulsation motion artifacts
Contrast-enhanced CTA
On CTA, aortic dissection is diagnosed by the presence of two distinct lumens with a visible intimal flap or by detection of two lumens by their differing rates of opacification with contrast material
Contrast-enhanced CT has a sensitivity and specificity of 98% to 100% in diagnosing aortic dissection, but false-negative results may occur with inadequate contrast bolus. CTA allows three-dimensional reconstruction for evaluation of the dissection and branch vessels and is critical for endovascular repair
Characteristics of false lumen
If the false lumen is completely thrombosed, it demonstrates low attenuation.
The false lumen usually has slower flow and a larger diameter than the true lumen
Echocardiogram (and ultrasound) diagnosis of aortic dissection is based on the presence of an _________________ with independent motion within the aortic lumen that separates the true and false lumens.
Undulating intimal flap
Features of the true lumen on TEE include a __________________________
Smaller lumen, systolic expansion, systolic anterograde flow, communication from the true to the false lumen in systole, and early and fast contrast-enhanced echocardiographic flow
TEE may not adequately visualize the distal ascending aorta and proximal aortic arch, but it interrogates the remaining thoracic aortic segments
True or False
Routine coronary angiography is not recommended before surgery for acute type A aortic dissection because of concern about delay in emergency surgery.
True
Coronary angiography may be technically difficult in the setting of dissection. Arterial access may fail to gain entry into the true lumen, and injury to the aorta from the catheter or guidewire may cause extension of the dissection or perforation of the aorta.
A bedside risk assessment stratifies patients into low (score 0), intermediate (score 1), and high (score 2 to 3) risk group
Aortic Dissection Detection [ADD] Risk Score
Give high risk conditions
• Marfan syndrome
• Family history of aortic disease
• Known aortic valve disease
• Recent aortic manipulation
• Known thoracic aortic aneurysm
Give high risk pain features
Chest, back, or abdominal pain described as the following:
• Abrupt in onset
• Severe in intensity
• Ripping or tearing
Give high risk exam features
• Evidence of perfusion deficit
• Pulse deficit
• Systolic BP differential
• Focal neurologic deficit (in conjunction with pain)
• Murmur of aortic insufficiency (new or not known to be old and in conjunction with pain)
• Hypotension or shock state
Disposition for patients with ADD risk score of >/= 2
Immediate surgical consultation and arrange for expedited aortic imaging.
Initial medical management includes stabilizing the patient, controlling pain, and lowering blood pressure with beta blockers to ___________________
Reduce the rate of rise in the force (dP/dt) of left ventricular contraction.
Emergency surgery improves survival for acute type A dissections with an 18% in-hospital mortality for surgically treated and ______ mortality for medically treated patients
56%
Reduction of systolic blood pressure to ______________________ and a heart rate of 60 to 80 beats/min is recommended.
100 to 120 mm Hg or the lowest level necessary for adequate perfusion
When encountering refractory hypertension in acute dissection one must consider ______________
Renal artery malperfusion (especially with signs of renal ischemia)
Effect of pericardiocentesis in patients with dissection and cardiac tampnade?
Pericardiocentesis for acute hemopericardium in patients with dissection can result in recurrent bleeding and acute hemodynamic collapse, especially if a larger volume of fluid is removed and increased blood pressure causes further brisk bleeding into the pericardial space.
Hypotension or shock from h cardium secondary to ascending dissection requires emergency aortic surgery.
In patients with persistent hypotension or shock from hemopericardium due to type A dissection who will not survive open surgery, careful aspiration of small volumes of pericardial fluid associates with improved blood pressure and may be lifesaving and should be considered in this setting.
Definitive therapy for acute aortic dissection includes _____________ for type A dissection in patients considered surgical candidates
Emergency surgery
In large registries, the mortality rate of patients with type A aortic dissection undergoing surgery was 18%, as opposed to 56% in those treated medically (typically because of advanced age and comorbid conditions)
Factors associated with mortality include shock, heart failure, cardiac tamponade, MI, renal failure, age, extent of dissection, and malperfusion.1
Acute retrograde type A dissection with a primary intimal tear in the descending aorta is usually treated _____________
Surgically
Patients with acute TBAD have a lower acute mortality rate than do those with acute type A dissection, with overall in-hospital mortality rates of approximately ______
10%
The in-hospital mortality rate is lower for uncomplicated type B dissection, reported as _________ in those requiring only medical therapy
1% to 6%
Indications for TEVAR (or less commonly OSR when TEVAR is not feasible) in complicated TBAD include
Rupture/Impending rupture
Malperfusion
Hemothorax
Refractory pain
Refractory hypertension
dilatation (>55 mm)
Rapid increase in aortic diameter
Recurrent symptom
___________ performed as expediently as possible, is the treatment of choice for acute type A aortic dissection to prevent life-threatening complications
Open surgical repair
Surgical goals are to excise the intimal tear; to restore flow in the true lumen and obliterate the false channel by oversewing the edges of the aorta; and to reconstitute the aorta with placement of an interposition graft.
In type A dissection, AR is treated by _______________ or by prosthetic AVR.
Resuspension of the aortic valve leaflets
_________________ is a potentially lethal complication that may occur during TEVAR for TBAD, emphasizing the requirement for an open repair team at institutions performing TEVAR for aortic dissection.
Retrograde ascending dissection
first randomized controlled trial on acute aortic dissection and compares OMT with OMT plus TEVAR, performed with the aim to cover the primary entry tear in patients with uncomplicated ABAD
One-year results demonstrated that thrombosis of the FL and reduction of its diameter are induced by the stent-graft in uncomplicated ABAD patients, but long-term results are needed
ADSORB trial
One hundred forty patients in stable clinical condition at least 2 weeks after index dissection were randomly subjected to elective stent-graft placement in addition to optimal medical therapy (n=72) or to optimal medical therapy alone (n=68) with surveillance
There was no difference in all-cause deaths, with a 2-year cumulative survival rate of 95.6+/-2.5% with optimal medical therapy versus 88.9+/-3.7% with TEVAR (P=0.15)
INSTEAD trial
In the first randomized study on elective stent-graft placement in survivors of uncomplicated type B aortic dissection, TEVAR failed to improve 2-year survival and adverse event rates despite favorable aortic remodeling.
Typical indications for TEVAR (or OSR) in chronic type B AD include
Progressive aortic enlargement (>5 to 10 mm/year)
Aneurysmal enlargement (>55 to 60 mm)
Malperfusion syndromes
Recurrent pain
Currently, OSR is reserved for patients with aortic diameters greater than ______________ who are good surgical candidates, including those with heritable/genetic aortic conditions, and at greater than 60 mm for reasonable candidates, whereas those at high surgical risk should be considered for ___________ at dedicated centers.
55 to 60 mm
TEVAR
The __________________ are the areas at highest risk for aneurysm formation after aortic dissection.
Distal arch and the proximal descending aorta
Typical imaging after acute dissection includes CT or MRA at ____________ thereafter
1 to 3, 6, and 12 months and annually
Clinical and Imaging Characteristics Predicting Risk of Late Aortic Complications in Initially Uncomplicated Type B Aortic Dissection
Primary entry tear diameter >10 mm
Initial aortic diameter >40 mm
False lumen diameter >22 mm
Partially thrombosed false lumen
Saccular false lumen formation
True or False
Many late deaths following surgery for aortic dissection result from rupture of the aorta at the site of previous dissection or from rupture of another aneurysm at a remote site.
True
Rapid aortic growth (____________) or aortic diameter greater than _________ are risk factors for rupture.
> 5 mm/year
> 60 mm
In general, patients with descending aorta diameter after dissection that exceeds ___________ or if the rate of aortic expansion exceeds ___________ should have evaluation for repair.
5.5 to 6 cm
1 cm/year
___________ defined as a hematoma in the medial layer of the aortic wall without identifiable communication between the lumen and hematoma and no evidence of an intimal flap or false lumen.
Aortic IMH, representing 10% to 20% of acute aortic syndromes (and higher incidence [30%] in Asia
IMH involves the ascending aorta in 30%, the arch in 10%, and the ________________ in 60% to 70%.
Descending aorta
IMH may result from rupture of the _____________ and subsequent mural hemorrhage.
Vasa vasorum
Supporting this theory is the location of IMH in the outer aortic media in distinction to the inner medial location of a classic dissection.
IMH is classified as _______________ as for classic aortic dissection.
Type A or type B
The proximity of the IMH to the adventitia may explain the frequent coexistence of _________________, ________________, _________________ and underlies the higher risk for aortic rupture.
Pleural effusion, pericardial effusion, and periaortic hematoma
__________ is less common in IMH
Malperfusion
__________________ is the hallmark of IMH in imaging
Crescentic or circumferential wall thickening without a visible intimal flap
CT features of IMH
Non–contrast-enhanced CT - area of high attenuation (due to bleeding) in the aortic wall
Contrast-enhanced CT - the aortic wall demonstrates low attenuation (because no contrast material enters the wall)
TEE features of IMH
Focal crescentic or circumferential aortic wall thickening ≥5 mm
An eccentric aortic lumen, displaced intimal calcification
Areas of echolucency within the aortic wall and no intimal flap or flow in the aortic wall
Findings associated with higher complication risk
Focal intimal disruptions
Ulcer-like projections (ULP) (a localized blood-filled pouch protruding into the hematoma in the aortic wall which may be due to micro-intimal defects)
Focal contrast enhancement (intramural blood pools) within the hematoma
Thick hematoma
Large aortic diameter
IMH has a ________________ distinct from an aneurysm with mural thrombus
Smooth lumen and curvilinear wall
Thickening beneath the intima suggests IMH, whereas thickening above the intima (on the luminal side) occurs with mural thrombus.
In contrast to aortic atherosclerosis, IMH is not typically associated with diffuse intimal irregularities unless related to a penetrating ulcer.
Current guidelines recommend _________ for type A IMH especially in the setting of hemodynamic instability, hemopericardium, rupture, or proximal aortic complications, and ___________ for type B IMH.
Type A - surgery
Type B - medical therapy
Type B IMH is treated ___________ in the vast majority with endovascular procedures performed for complications
Medical therapy
representing approximately 5% of acute aortic syndromes, is an atherosclerotic plaque that penetrates through the internal elastic lamina into the media and often associates with a variable degree of IMH.
Penetrating Atherosclerotic Aortic Ulcer
PAUs are more common in the ___________________
mid-to distal descending aorta than in the arch or ascending or abdominal aorta
CT findings of PAU
Focal aortic ulceration, associated IMH, and a calcified, displaced intima
Typically, a crater-like outpouching with irregular edges occurs in the setting of heavy atherosclerosis.
In general, patients with ascending PAUs undergo surgical resection. Stable patients with type B PAUs may be managed medically, with close follow-up and serial imaging.
Patients with refractory or r rent pain, overlying IMH or periaortic hemorrhage, or rapid increase in size are at increased risk of rupture and should undergo TEVAR
Indications for TEVAR (or less often, surgery) may include hemorrhage, periaortic hematoma, expanding pseudoaneurysm, saccular aneurysm formation, continued pain, or rupture.
Predictors of disease progression include increasing aortic wall thickness, ulcer craters greater than 15 to 20 mm in diameter or greater than 10 mm in depth, increasing aortic hematoma, and increasing pleural effusion
The classic triad of an infected aortic aneurysm includes
Fever (67%)
Pain (77%) in the abdomen, back, or chest
Pulsatile tender mass
Infected aneurysms most commonly involve the ________________ (60%) and the descending aorta.
Infrarenal aorta
Infected TAAs are less common, most commonly affect the __________________, and are often accompanied by rupture (in 44%) or pseudoaneurysm.
Descending aorta
The most common microorganisms associated with infected aortic aneurysms include __________________, but infections with gram-negative bacilli and fungi can occur.
___________ may directly penetrate an intact intima of a normal aortic wall and lead to arteritis and aneurysm formation.
Staphylococcus aureus, streptococcal, and Salmonella species
Salmonella
Thus, suspicion for aortic seeding is prudent when Salmonella bacteremia occurs.
Features on CT include
Disruption of calcification, irregular wall thickening, periaortic mass, rim enhancement, and periaortic stranding.
The presence of gas and vertebral body erosion is highly suggestive of infection.
MRI features of infected aneurysms include
Soft tissue mass, stranding, and rim enhancement.
Overall mortality from infected aortic aneurysms ranges from ___________ with medical therapy alone
50% to 100%
_______ of infected AAAs involves excision and debridement or exclusion of the infected aortic tissue, revascularization (in situ or extra-anatomic bypass), and prolonged antibiotic therapy.
OSR
Acute and chronic management pathway for type B intramural hematoma (IMH)
Medical treatment and close follow-up with imaging techniques
• Every 3 months (1st year)
• Every 6 months (2nd and 3rd year)
• Annually (3rd year)
Tumors affecting the aorta most commonly arise secondarily from direct invasion by adjacent cancer or metastases, especially from the _______________
Lung and esophagus
The average age at diagnosis is 60 years, with a male preponderance.
These tumors most commonly localize in the descending thoracic (38%) and abdominal (43%) aorta
Symptoms include pain, embolism, claudication, visceral ischemia, or constitutional symptoms.
