Management of acute type B aortic dissection

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Management of acute type B aortic dissection Powered By Docstoc
					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
          Eggebrecht, H, Eur Heart J 2006;27:489.


for acute type B aortic
dissection
• 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

  Management of ruptured
          reexpansion of true lumen
          aortic remodelling with healing of false lumen.
  acute dissection type B
Endovascular treatment
    • Stent graft
    • Stent
of acute type B aortic
    • composite

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
2- Open repair for acute
  arrest

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
                 Penetrating ulcer/intramural hematoma
                   Asymptomatic                                       III                   C
                   Symptomatic                                       IIa                    C
                 Acute traumatic                                       I                    B
                 Chronic traumatic                                   IIa                    C
                 Acute Type B dissection
                   Ischemia                                            I                    A
                   No ischemia                                       IIb                    C
                 Subacute dissection                                 IIb                    B
                 Chronic dissection                                  IIb                    B
                 Degenerative descending
                   >5.5 cm, comorbidity                              IIa                    B
                   >5.5 cm, no comorbidity                           IIb                    C
                   <5.5 cm                                            III                   C
                 Arch
                   Reasonable open risk                               III                   A
                   Severe comorbidity                                IIb                    C
                 Thoracoabdominal/Severe comorbidity                 IIb                    C

     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 = 0.1-
  0.74 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           Benefit ≥ Risk             Risk ≥ Benefit
                            Additional studies        Additional studies with    No additional studies
                            with focused              broad objectives           needed
                            objectives needed         needed; Additional
                                                      registry data would be     Procedure/Treatment
  Procedure/                IT IS REASONABLE          helpful                    should NOT be
  Treatment SHOULD          to perform                                           performed/administered
  be performed/             procedure/administer      Procedure/Treatment        SINCE IT IS NOT
  administered              treatment                 MAY BE                     HELPFUL AND MAY BE
                                                      CONSIDERED                 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
             • Marfan Syndrome                         1
             • 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                      2
     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.
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 Ehlers-
                  Danlos 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    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
  I IIa IIb III
                     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
                                                 No      Hypotension
     Rate/Pressure Control
                                         1              or shock state?
       Intravenous beta blockade
             or Labetalol
  (If contraindication to beta blockade                                   Yes
      substitute diltiazem or verapamil)
         Titrate to heart rate <60
                    +
                                                 Anatomic based management
           Pain Control
         Intravenous opiates
                                     2
        Titrate to pain control

        Systolic BP >120mm HG?
        Secondary pressure control
                BP Control
         Intravenous vasodilator             3
Titrate to BP <120mm HG (Goal is lowest
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                              Type B dissection

    Urgent surgical                                 Intravenous fluid bolus
 1 consultation                              1    •Titrate to MAP of 70mm HG
                 +                                          or Euvolemia
      Arrange for expedited                       (If still hypotensive begin
     operative management                    intravenous vasopressor agents)

 2   Intravenous fluid bolus                 2      Evaluate etiology of
       •Titrate to MAP of 70mm HG                   hypotension
              or Euvolemia                          • Review imaging study for
   (If still hypotensive begin                       evidence of contained
intravenous vasopressor agents)                    rupture
                                                    • Consider TTE to evaluate
 3   Review imaging study for:                       cardiac function
     • Pericardial tamponade
     • Contained rupture
                                             3      Urgent surgical
     • Severe aortic insufficiency                 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 intravenous                       Based on results from anatomic
rate and pressure control:                              based management:
                                          No
    Dissection involving                                         Etiology of hypotension
   the ascending aorta?                                          Amenable to operative
                                                                      management?
                            Ongoing medical management

                            Close hemodynamic monitoring
                            Maintain systolic BP < 120mm Hg
                                (Lowest BP that maintains
                                  end organ perfusion)



  Operative or                                                            Operative or
  intervention
                             Complications requiring operative            intervention
                              or interventional management?
         al           Yes                                        Yes             al
  manageme                     Limb or mesenteric ischemia                manageme
         nt                      Progression of dissection                       nt
                                   Aneurysm expansion
                                Uncontrolled hypertension
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 IIa IIb 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

				
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