Annual meeting
of RCST
Kittichai Luengtaviboon M.D.
King Chulalongkalongkorn Memorial Hospital
16 July 2011
• Still one of the most leathal disease of the aorta.
• Acute type A aortic dissection is a surgical disease.
• Acute type B is medical disease unless it is complicated.
Aortic dissection – what
is the current situation?
• Diagnosis – markers-plassma smooth muscle heavy chain
myosin, D-dimer, CRP –diagnostic promise but lack of
large prospective studies.
• Extent of surgical management
Acute type A aortic
dissection
• Disruption of medial layer of aorta with bleeding within,
resulting in separation of the layers of the wall
• Intimal tear is present in 90%
• This may rupture through adventitia or back through the
intima into the lumen.
• Non invasive imaging, IMH is present in 15%
• In autopsy only 4% did not have intimal tear
definition
• 1. acute aortic valve regurgitation
• 2. myocardial ischemia and infarction
• 3. pericardial effusion and tamponade
Cardiac complications
• Proximal part or aortic root :
aortic commissure resuspension if
not severely involved
not annulo aortic ectasia
otherwise
replacement = modified Bentall’s operation
aortic valve sparing = David’s reimplantation
• Distal part or aortic arch
ascending aorta replacement with aortic cross clamping
aortic arch replacement
hemiarch
total arch with elephant trunk
frozen elephant trunk
Extent of surgical management of
acute type A aortic dissection
• Remain the same :
resection of the intimal tear
obliteration of false lumen
replace aorta with prosthetic vascular graft
resuspension of aortic commissures
Surgical principle
• In experienced center, mortality is 3.5-10%, but much
higher overall.
• Causes of death- stroke, mesenteric ischemia, renal
failure and myocardial ischemia.
Result of surgical repair of
aortic dissection
• Phases
acute within 14 days
subacute from 14 days to 2 months
chronic after 2 months
behave like aneurysm
rupture is the risk
malperfusion is rare
Aortic dissection type B
•
•
•
•
Not as lethal as acute type A aortic dissection
85% of patients will be successfully managed medically.
Only 15% require interventional or surgical treatment
The most common indications are
aortic rupture – pain, hemothorax, frank rupture with shock
malperfusion syndrome
abdominal
lower extremity
spinal cord
Natural history of acute
type B dissection
• Patients with complicated acute type B aortic dissections
have a very high (>50%)likelihood of dying and require
emergency surgical or interventional treatment
Svensson et al
Expert concensus document
Ann Thorac Surg 2008;85:S1-41
• Toru Suzuki, et al
• Circulation 2003;108;II-312-II-317.
384patients (65 +- 13 years, male 71%) with acute type B aortic dissection
in hospital mortality 13%
most death occurred within the first week.
factors associated with increased in hospital mortality on univariate analysis
were
hypotension/ shock
widened mediastinum
periaortic hematoma
excessive dilated aorta >6cm
inhospital complications of coma, altered consciousness, mesenteric/limb
ischemia, acute renal failure, and surgical management.
Clinical profiles and outcomes of acute type B aortic
dissection in the current era: Lessons from the
International Registry of Aortic Dissection (IRAD)
• Branch vessel involvement or malperfusion was an
independent predictor of early death, odd ratio = 2.9
• Options for type B malperfusion are
open surgical repair
percutaneous fenestration + bare metal stenting to
create a reentry tear
TEVAR to cover the primary tear will reverse dynamic
obstruction
• The early mortality for those requiring operative repair
ranges from 18% to 36%.
• What is the mechanism?
dynamic – high pressure in false lumen with collapse of
true lumen ( due to lack of re entry intimal tear)
- aortic fenestration – open vs balloon is
treatment of choice
- some groups recommend TEVAR to prevent
flow into false lumen
Management of
malperfusion syndrome
Dynamic obstruction
• Static malperfusion
aortic branch stenting is treatment of choice
extra anatomical bypass is the alternative.
Static obstruction
• Wilson Y Szeto, et al U. of Pennsylvania
• Ann Thorac Surg 2008;86:87-94
from 2004-2007 35 patients with acute complicated type B aortic
dissection were treated with TEVAR
18 (51.4%) for rupture 17 (48.6% )for malperfusion –
mesenteric or renal 5
lower extremities 3
both 9
in malperfusion group distal adjunct to expand the true lumen include
infrarenal aortic stent 4
mesenteric/renal stent 4
iliofemoral stent 7
Results of a new surgical paradigm: endovascular repair for
acute complicated type B aortic dissection
• Results
technical success (coverage of primary tear) was
achieved in 34 (97.1%)
coverage of left subclavian 25 (71.4%)
30 day mortality = 2.8%
stroke = 2.8%
spinal cord ischemia 5.7% - transient 2.8% permanent
vascular access 14.2%
G Michael Deeb, Himanshu J. Patel, David M Williams
U of Michigan
J Thorac Cardiovasc Surg 2010;140:S98-S100.
Malperfusion – adverse risk factor for survival in both type a and
b dissection
1/3 of acute type A, if delayed diagnosis with organ failure ->
aortic repair has poor outcome
treated malperfusion first = overall mortality 25% including a
15%mortality from rupture. ( compared to 89% of historical
control)
Treatment for malperfusion syndrome in
acute type A and B aortic dissection: A long
term analysis
• 196 patients with acute type A dissection, 70 with organ
malperfusion and end organ dysfunction
percutaneous end organ reperfusion and medical
stabilization, followed by surgical repair
95% success rate in opening obstructed vessel
percutaneously
38% died before surgical repair
19% of rupture
19% of malperfusion complication
126 patients without malperfusion or end organ dysfunction ->
early operative mortality = 9.5%
• Meta analysis of 39 studies
609 patients with type B dissection
procedure success 98%
major complications
21% in acute
9.1% in chronic
mortality 5.2%
Endovascular technique
for acute type B aortic
dissection
Eggebrecht, H, Eur Heart J 2006;27:489.
• TEVAR for acute dissection with malperfusion
90% success excluding the entry tear and reestablishing perfusion
20% mortality
30% complication
• Long term results for percutaneous fenestration with bare metal
stenting to recreate a reentry tear and establish reperfusion in acute
type B dissection with malperfusion
69 patients
technical success rate 96%
17% mortality, 7% from false lumen rupture, 10% of malperfusion
syndrome complication
1 yr survival 76%, 5 yr survival 65%
freedom from open repair or rupture at 1 yr = 80%, 5 yr = 55%
• The most common site of rupture is at the intimal tear (
proximal descending aorta)
• Options of treatment
1- TEVAR
principle of treatment
coverage of intimal tear with stent graft
reexpansion of true lumen
aortic remodelling with healing of false lumen.
Management of ruptured
acute dissection type B
• Stent graft
Endovascular
treatment
• Stent
of acute
• compositetype B aortic
dissection
• Principle of open repair for acute type B dissection
resect intimal tear and segment of descending aorta
prone to rupture or has ruptured
obliteration of proximal and distal false lumen
direct flow into true lumen only
usually replace proximal ½ or ¾ of descending aorta
• Incision – left thoracotomy
• Technique- under deep hypothermia with circulatory
arrest
2- Open repair for acute
type B dissection with
rupture
• Medical management
hospital mortality 10-15%
survival at 1 yr
73%
5 yr
58%
 Surgical treatment
hospital mortality
28-65%
paraplegia
30-36%
survival at 1 yr 48%
5 yr 29%
Elefteriades JA, Ann Thorac Surg 1999;67(6):2002
Type B aortic dissection
• Ahmad Zeeshan, et al
• J Thorac Cardiovasc Surg 2010;140:109-115
2002-2010 170 patients with type B dissection, U of Pennsylvania
data base – 147 acute – 70 uncomplicated , 77 complicated
group A – endovascular repair =45
group B – surgical treatment = 20 (mostly resection of aorta under
DHCA)
medical treatment = 12
Mortality 30 day
A = 4%, B surgical = 40% and medical 33%
Survival 1,3,5 yrs
A = 82,79, 79% vs B = 58, 52, 44%
Thoracic Endovascular aortic repair for acute complicated type B
aortic dissection: superiority relative to conventional open surgical
and medical therapy
Society of Thoracic Surgeons Recommendations
for Thoracic Stent Graft Insertion (summary
Entity/Subgroup
)
Classification
Level of Evidence
Asymptomatic
III
C
Symptomatic
IIa
C
Acute traumatic
I
B
IIa
C
I
A
IIb
C
Subacute dissection
IIb
B
Chronic dissection
IIb
B
>5.5 cm, comorbidity
IIa
B
>5.5 cm, no comorbidity
IIb
C
<5.5 cm
III
C
Reasonable open risk
III
A
Severe comorbidity
IIb
C
IIb
C
Penetrating ulcer/intramural hematoma
Chronic traumatic
Acute Type B dissection
Ischemia
No ischemia
Degenerative descending
Arch
Thoracoabdominal/Severe comorbidity
Note: Table 15 in full-text version of TAD Guidelines. Reprinted from Svensson et al. Expert
consensus document on the treatment of descending thoracic aortic disease using endovascular stent
grafts. Ann Thorac Surg. 2008;85:S1– 41.
• Although primary medical therapy for uncomplicted type B
dissection may improve hospital survival, it has NOT changed
long term survival.
• Most deaths are related to comorbid conditions.
• Late complications from distal aortic dissection are estimated
to occur in 20-50% of patients.
• The sequelae include
new dissection
rupture of a weak false channel
most commonly saccular or fusiform aneurysmal
degeneration of the thinned walls of the false channel.
Chronic type b dissection
• Growth rate of chronically dissected distal aorta = 0.10.74 cm per year.
strongly dependent on initial diameter of aorta after
dissection and control of hypertension
• Genoni freedom from aortic events at a mean of 4.2 years
was 80% in those treated with beta blocker VS 47% in
those treated with other antihypertensive regimens.
• False lumen patency due to presence of distal
fenestrations
thrombosis of false lumen may be associated with a
slower rate of aortic growth – controversial.
• Same principle of treatment as degenerative descending thoracic
aortic aneurysm , BUT
more likely to rupture, indication for surgery at diameter 5.5
cm.
almost always required replacement from distal aortic arch to
lower descending or thoraco abdominal aorta
common technique is via left thoraco abdominal incision under
DHCA
distal anastomosis to aorta with diameter < 4 cm.
resect dissecting membrane distally to perfuse both lumina
remove clots from false lumen distally
Chronic dissection type B
• This principle of open repair allows removal of the
portion of aorta at risk of rupture, but does not eliminate
risk of subsequent aneurysmal degeneration of the
residual distal aortic false lumen.
• Nienaber reported results of stent graft in subacute and chronic
type B dissection in 1999.
• The rationale is covering the primary intimal tear with stent
graft promotes false lumen thrombosis and subsequent aortic
remodelling by eliminating antegrade (or occasionally
retrograde) flow into the false lumen.
• Based on the INSTEAD (Investigation of STEnt grafts in
patients with type B Aortic Dissection) study, it appears that
stent-graft treatment of patients with chronic aortic dissection
offers no benefit in terms of reducing the risk of aortic rupture
or enhancing life expectancy.
• Regardless of the approach used, as long as patients have
residual dissected aorta, they remain at risk for late
aneurysmal degeration and rupture of the false lumen
and require indefinite serial imaging surveillance, close
blood pressure monitoring and negative inotropic
medication.
Applying Classification of Recommendations and Level of
Evidence
Class I
Class IIa
Class IIb
Class III
Benefit >>> Risk
Benefit >> Risk
Additional studies
with focused
objectives needed
Benefit ≥ Risk
Additional studies with
broad objectives
needed; Additional
registry data would be
helpful
Risk ≥ Benefit
No additional studies
needed
Procedure/
Treatment SHOULD
be performed/
administered
IT IS REASONABLE
to perform
procedure/administer
treatment
Procedure/Treatment
MAY BE
CONSIDERED
Procedure/Treatment
should NOT be
performed/administered
SINCE IT IS NOT
HELPFUL AND MAY BE
HARMFUL
Level of Evidence:
Level A:
Data derived from multiple randomized clinical trials or meta-analyses
Multiple populations evaluated;
Level B:
Data derived from a single randomized trial or nonrandomized studies
Limited populations evaluated
Level C:
Only consensus of experts opinion, case studies, or standard of care
Very limited populations evaluated
2010 ACCF/AHA/AATS/ACR/ASA/
SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and
Management of Patients with Thoracic Aortic Disease
Developed in partnership with the American College of Cardiology
Foundation/American Heart Association Task Force on Practice
Guidelines, American Association for Thoracic Surgery, American
College of Radiology, American Stroke Association, Society of
Cardiovascular Anesthesiologists, Society for Cardiovascular
Angiography and Interventions, Society of Interventional
Radiology, Society of Thoracic Surgeons, and Society for Vascular
Medicine.
Endorsed by the North American Society for Cardiovascular
Imaging.
Estimation of Pretest Risk of Thoracic Aortic Dissection
High Risk Conditions
1
• Marfan Syndrome
• Connective tissue disease*
• Family history of aortic disease
• Known aortic valve disease
• Recent aortic manipulation (surgical or
catheter-based)
• Known thoracic aortic aneurysm
• Genetic conditions that predispose to AoD†
* Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, Turner syndrome, or other
connective tissue disease.
†Patients with mutations in genes known to predispose to thoracic aortic aneurysms and
dissection, such as FBN1, TGFBR1, TGFBR2, ACTA2, and MYH11.
Estimation of Pretest Risk of Thoracic Aortic Dissection
High Risk Pain Features
Chest, back, or abdominal pain features
described as pain that:
• is abrupt or instantaneous in onset.
• is severe in intensity.
• has a ripping, tearing, stabbing, or
sharp
quality.
2
Estimation of Pretest Risk of Thoracic
Aortic Dissection
High Risk Examination Features
3
• Pulse deficit
• Systolic BP limb differential > 20mm Hg
• Focal neurologic deficit
• Murmur of aortic regurgitation (new or
not
known to be old and in conjunction with
pain)
Recommendations for Estimation of Pretest Risk of
Thoracic Aortic Dissection
I IIa IIb III
Patients presenting with sudden onset of severe
chest, back, and/or abdominal pain, particularly those
less than 40 years of age, should be questioned about a
history and examined for physical features of Marfan
syndrome, Loeys-Dietz syndrome, vascular EhlersDanlos syndrome, Turner syndrome, or other
connective tissue disorder associated with thoracic
aortic disease.
Recommendations for Estimation of Pretest Risk of
Thoracic Aortic Dissection
I IIa IIb III
In patients with suspected or confirmed aortic
dissection who have experienced a syncopal
episode, a focused examination should be
performed to identify associated neurologic injury
or the presence of pericardial tamponade.
I IIa IIb III
All patients presenting with acute neurologic
complaints should be questioned about the
presence of chest, back, and/or abdominal pain
and checked for peripheral pulse deficits as
patients with dissection-related neurologic
pathology are less likely to report thoracic pain
than the typical aortic dissection patient.
Risk-based Diagnostic Evaluation:
Patients with High Risk of TAD
Patients at high-risk for TAD are those that present with at least 2
high-risk features (outlined in more detail in the following
slides).
The recommended course of action for high-risk TAD patients is to
seek immediate surgical consultation and arrange for expedited
aortic imaging.
Expedited aortic imaging
•
•
•
TEE (preferred if clinically unstable)
CT scan (image entire aorta: chest to pelvis)
MR (image entire aorta: chest to pelvis)
Risk Factors for Development of Thoracic
Aortic Dissection
Conditions Associated With Increased Aortic Wall Stress
•
•
•
•
•
•
Hypertension, particularly if uncontrolled
Pheochromocytoma
Cocaine or other stimulant use
Weight lifting or other Valsalva maneuver
Trauma
Deceleration or torsional injury (eg, motor vehicle crash,
fall)
• Coarctation of the aorta
Note: Information on this slide is adapted from Table 9 in full-text version of TAD Guidelines
Risk Factors for Development of Thoracic Aortic
Dissection (continued)
Conditions Associated With Aortic Media Abnormalities
Genetic
• Marfan syndrome
• Ehlers-Danlos syndrome, vascular form
• Bicuspid aortic valve (including prior aortic valve
replacement)
• Turner syndrome
• Loeys-Dietz syndrome
• Familial thoracic aortic aneurysm and dissection
syndrome
Note: Information on this slide is adapted from Table 9 in full-text version of TAD Guidelines
Risk Factors for Development of Thoracic Aortic
Dissection (continued)
Conditions Associated With Aortic Media Abnormalities
(continued)
Inflammatory vasculitides
• Takayasu arteritis
• Giant cell arteritis
• Behçet arteritis
Other
• Pregnancy
• Autosomal dominant polycystic kidney disease
• Chronic corticosteroid or immunosuppression agent
administration
• Infections involving the aortic wall either from bacteremia or
extension of adjacent infection
Note: Information on this slide is adapted from Table 9 in full-text version of TAD Guidelines
Recommendations for Screening
Tests (continued)
I IIa IIb III
Urgent and definitive imaging of the aorta using
transesophageal echocardiogram, computed
tomographic imaging, or magnetic resonance imaging
is recommended to identify or exclude thoracic aortic
dissection in patients at high risk for the disease by
initial screening.
I IIa IIb III
A negative chest x-ray should not delay definitive
aortic imaging in patients determined to be high risk
for aortic dissection by initial screening.
Recommendations for Diagnostic
Imaging Studies
I IIa IIb III
Selection of a specific imaging modality to
identify or exclude aortic dissection should
be based on patient variables and
institutional capabilities, including immediate
availability.
I IIa IIb III
If a high clinical suspicion exists for acute
aortic dissection but initial aortic imaging is
negative, a second imaging study should be
obtained.
Recommendations for Initial Management
Initial management of thoracic aortic dissection should be
directed at decreasing aortic wall stress by controlling heart
rate and blood pressure as follows:
I IIa IIb III
a. In the absence of contraindications,
intravenous beta blockade should be
initiated and titrated to a target heart rate of
60 beats per minute or less.
I IIa IIb III
b. In patients with clear contraindications to
beta blockade, nondihydropyridine calcium
channel–blocking agents should be used as
an alternative for rate control.
Recommendations for Initial
Management (continued)
I IIa IIb III
I IIa IIb III
c. If systolic blood pressures remain greater than
120mm Hg after adequate heart rate control
has been obtained, then angiotensin-converting
enzyme inhibitors and/or other vasodilators
should be administered intravenously to further
reduce blood pressure that maintains adequate
end-organ perfusion.
d. Beta blockers should be used cautiously in the
setting of acute aortic regurgitation because
they will block the compensatory tachycardia.
Recommendations for Initial
Management (continued)
I IIa IIb III
Vasodilator therapy should not be initiated
prior to rate control so as to avoid associated
reflex tachycardia that may increase aortic
wall stress, leading to propagation or
expansion of a thoracic aortic dissection.
Acute AoD Management Pathway
STEP 2: Initial management of aortic wall stress
• Obtain accurate blood pressure prior to beginning treatment.
• Measure in both arms.
• Base treatment goals on highest blood pressure reading.
Acute AoD Management Pathway
STEP 2: Initial management of aortic wall stress
Intravenous rate and pressure control
Rate/Pressure Control
No
1
Intravenous beta blockade
or Labetalol
(If contraindication to beta blockade
substitute diltiazem or verapamil)
Hypotension
or shock state?
Yes
Titrate to heart rate <60
+
Pain Control
Intravenous opiates
Anatomic based management
2
Titrate to pain control
Systolic BP >120mm HG?
Secondary pressure control
BP Control
Intravenous vasodilator
Titrate to BP <120mm HG (Goal is lowest
3
possible BP that maintains adequate end organ
perfusion)
Acute AoD Management Pathway
STEP 2: Initial management of aortic wall stress
Anatomic based management
Type A dissection
Urgent surgical
1 consultation
+
Arrange for expedited
operative management
2
Intravenous fluid bolus
•Titrate to MAP of 70mm HG
or Euvolemia
(If still hypotensive begin
intravenous vasopressor agents)
3
Review imaging study for:
• Pericardial tamponade
• Contained rupture
• Severe aortic insufficiency
Type B dissection
1
Intravenous fluid bolus
•Titrate to MAP of 70mm HG
or Euvolemia
(If still hypotensive begin
intravenous vasopressor agents)
2
Evaluate etiology of
hypotension
• Review imaging study for
evidence of contained
rupture
• Consider TTE to evaluate
cardiac function
3
Urgent surgical
consultation
Acute AoD Management Pathway
STEP 3: Definitive management
• Depending on the results from the pressure control or
anatomic based management, continued treatment will
involve either:
– ongoing medical management, or
– operative or interventional management.
Acute AoD Management Pathway
STEP 3: Definitive management
Based on results from anatomic
based management:
Based on results from intravenous
rate and pressure control:
Dissection involving
the ascending aorta?
No
Ongoing medical management
Etiology of hypotension
Amenable to operative
management?
Close hemodynamic monitoring
Maintain systolic BP < 120mm Hg
(Lowest BP that maintains
end organ perfusion)
Operative or
intervention
al
manageme
nt
Complications requiring operative
or interventional management?
Yes
Limb or mesenteric ischemia
Progression of dissection
Aneurysm expansion
Uncontrolled hypertension
Yes
Operative or
intervention
al
manageme
nt
Recommendations for Definitive Management
(continued)
I IIa IIb III
Acute thoracic aortic dissection involving the
descending aorta should be managed medically
unless life-threatening complications develop (ie,
malperfusion syndrome, progression of dissection,
enlarging aneurysm, inability to control blood
pressure or symptoms).
Guidelines for Thoracic Aortic Disease
Recommendation for Intramural
Hematoma Without Intimal Defect
Recommendation for Intramural
Hematoma Without Intimal Defect
I IIaIIb III
It is reasonable to treat intramural hematoma similar
to aortic dissection in the corresponding segment of
the aorta.
Male 76 with Pau of arch
and IMH of ascending and
severe TVD.
Acute AoD Management Pathway
STEP 4: Transition to outpatient management and
disease surveillance
• If no complications present requiring operative or interventional
management, transition to:
• Oral medications (beta blockade/ antihypertensives
regimen)
• Outpatient disease surveillance imaging
Note: For full algorithm, see Figure 26 in full-text version of TAD Guidelines