Endovascular management of Aortic Dissection

ENDOVASCULAR
TREATMENT OF
AORTIC
DISSECTION
SATYAM RAJVANSHI

AORTIC DISSECTION (AD)
 Disruption of the medial layer provoked by intramural bleeding.
 Results in separation of the aortic wall layers and subsequent formation of a True Lumen
(TL) and a False lumen (FL) with or without communication.
 An intimal tear is the initiating condition, resulting in tracking of the blood in a dissection
plane within the media – Identified on noninvasive imaging in 90%, on autopsy in 95%.
 Followed either by an aortic rupture in the case of adventitial disruption or by a re-entering
into the aortic lumen through a second intimal tear.
 Can be antegrade or retrograde.
 15% have Intramural hematoma.

ESC guideline. Eur heart J. 2014;35:2873-2926

EPIDEMIOLOGY
 Underestimated incidence. 1-4 cases per 100000 per year. Highest in Italy.
 0.5% of patients presenting with chest pain to ED.
Circulation 2013;127:2031–2037
 Incidence increases with age. Mean age 63 years.
 Males (65%) > Females
 Risk factors - Hypertension (70%)- uncontrolled commonly
- Pre-existing aortic diseases or aortic valve disease,
- History of cardiac surgery
- Cigarette smoking
- Direct blunt chest trauma
- IV drug abuse (e.g. cocaine and amphetamines)
 Risk factors in age < 40 yr - Marfan S. and other CTDs
IRAD registry. JAMA 2000;283:897–903

ACUTE DISSECTION
 ACUTE - diagnosed within 2 weeks of symptom onset. Highest mortality.
 SUBACUTE - survived first 2 weeks
 CHRONIC - survived first 8 weeks - Behave more like aneurysm
- Rupture is the risk
- Malperfusion is uncommon
ACC/AHA guideline. Circulation 2010;121:e266

ACUTE DISSECTION: SIGNS AND
SYMPTOMS
 Pain (95%) – Abrupt onset (85%)
 Sharp nature (65%)
 Tearing/Ripping (50%)
 Chest (75%) – Anterior (60%) > Post. (35%)
 Back (55%)
 Abdominal (30%)
 May extend down to hips and legs
 Malperfusion syndromes (30%)
 Hypotension/Shock (25%) - Tamponade
- Acute AR (33%)
- Aortic rupture
- Spinal shock
 Acute MI/Ischemia
 Syncope; CHB
 Neurological - Stroke; paraplegia
- Hoarseness
 Acute renal failure
 Mesenteric ischemia
Dynamic (FL pressure)
Static (Branch dissection)

ANATOMICAL
CLASSIFICATIO
N
 DeBakey
 Stanford : MC used
 Presentation and natural
history depends on type
 Therefore management and
prognosis is decided by type

ANATOMICAL
CLASSIFICATIO
N
 Type A and B behave
differently!

NATURAL HISTORY
TYPE A
Mortality (untreated)
 1st 24 hrs – 1-2% per hour
 1st 48 hrs – 36-72%
 1st week – 60-90%
Mortality (on Medical Mx only)
 1st 24 hrs – 24%
 1st 48 hrs – 29%
 1st week – 44%
 1st 2 weeks – 50%
 1st year – 90% - Most die in 3 mos.
TYPE B
Mortality (Untreated)
 1st month – 10%
 1st year – 15%
 5 years – 20%
‘Complicated’ Type B (on Medical Mx only)
 1st 48 hrs – 20%
 1st month – 25%
ESC task force. Eur heart J. 2001;22:1642-81

NATURAL HISTORY
PREDICTORS OF MORTALITY
Age > 70 yr
Hypotension
Pericardial tamponade
Myocardial infarct/ischemia
Stroke/Coma
Intestinal ischemia
Renal failure
Pulse differences
‘COMPLICATED’ TYPE B – 30-42% of
TBAAD
Persistent or recurrent pain
Uncontrolled HTN despite full medication
Early aortic expansion
Malperfusion
Signs of rupture (haemothorax, increasing
periaortic/mediastinal haematoma)
Retrograde dissection into the aortic arch
ESC task force. Eur heart J. 2001;22:1642-81

Grossly underdiagnosed!
 Most common , most lethal aortic emergency
 Among life-threatening causes of chest pain, AD has the highest mortality — an estimated 1-2% per hour for the
first 48 hours.
 Still a formidable diagnostic challenge in ED - As many as 65% AD missed in initial exam.
Freedman DL. Aortic dissection: Be suspicious or the autopsy will make diagnosis.
ED Legal Letter 2000; 11:105-116.
 Diagnostic delays of >24 hrs in 39 % patients. (31 % proximal AD, 53 % distal AD )
Viljanen T. Diagnostic difficulties in aortic dissection.
Ann Chir Gynaecol 1986;75:328–32

PRETEST
PROBABILITY
LOW PROBABILITY
 0-1 risk group features
present
HIGH PROBABILITY
 2-3 risk group features
OR
 Typical chest pain

CLASS I
CLASS I
CLASS I
CLASS IIa
CLASS I
CLASS I
CLASS IIa

IMAGING IN AORTIC DISSECTION
REQUIRED DETAILS
 MDCT – MC used – speed, availability and accuracy (>95% in diagnosis
and identification of side branch involvement)

MEDICAL MANAGEMENT
ANTI IMPULSE THERAPY
Reduces propagation tendency
 BP lowering: SBP 100-120
 Rule out significant AR
 Watch for oliguria
 HR lowering: ≤ 60 bpm
 Decreasing LV contraction velocity
 Decreasing Aortic wall shear stress

MEDICAL MANAGEMENT
ANTI IMPULSE THERAPY
 Beta blockers DOC – but cautious of significant
AR
 IV Labetalol
 IV Esmolol
 Additional drugs +/-
 IV Verapamil/Diltiazem
 IV Enalapril
 IV Nitroprusside
 Vasodilators always with background rate control
 Avoid Hydralazine – increase shear stress
PAIN CONTROL
 Opioids: Morphine DOC

ESC 2014
RECOMMENDATION
FOR AORTIC
DISSECTION

ACC/AHA/STS 2010
RECOMMENDATION
FOR THORACIC
STENT GRAFT
INSERTION

SURGICAL MANAGEMENT OUTCOME
TYPE A
 In hospital mortality - 27%
- 10% by 24 hours
- 16% by 7 days
- 20% by 14 days
(Still 30% mortality benefit at 2 weeks vs. Medical
Rx alone – so, clear TOC!)
 Survival post discharge - 96% at 1 year
- 91% at 3 years
TYPE B ‘COMPLICATED’
 In hospital mortality - 31%
 Paraplegia - varies 2-19%
 Survival post discharge - 83% at 3 year
(Poorer prognosis than Type A!)

 30 day mortality of types
of dissection with medical
/ surgical management

TBAAD Kaplan meier
survival curves

ENDOVASCULAR THERAPY vs. OPEN
SURGERY
Advantages
 Less Invasive – No thoracotomy/No CPB
 Less painful
 Less morbidity – No aortic clamp – Less stroke
– Less intercostal artery coverage –
Less paraplegia
 Shorter hospitalization
 Feasible in high surgical risk pts
 Feasible in hemodynamically unstable pts – less blood
loss
Disadvantages
 Suitable anatomy is pre-requisite
 Contrast related toxicity
 Higher cost
 More secondary interventions
 Lifelong follow-up required

ENDOVASCULAR THERAPY vs. OPEN
SURGERY
Advantages
 Less Invasive – No thoracotomy/No CPB
 Less painful
 Less morbidity – No aortic clamp – Less stroke
– Less intercostal artery coverage –
Less paraplegia
 Shorter hospitalization
 Feasible in high surgical risk pts
 Feasible in hemodynamically unstable pts – less blood
loss
Disadvantages
 Suitable anatomy is pre-requisite
 Contrast related toxicity
 Higher cost
 More secondary interventions
 Lifelong follow-up required
TBAAD TEVAR
• In hospital mortality rates - 5-9%
• Stroke - 2-6%
• Paraplegia - 1-3%

Contemporary Endovascular Rx -
Techniques
 Sealing primary entry tear - Stent Graft
- Bare stent
 Reperfusion of arterial ischemia - Balloon fenestration
- Stenting
 Hybrid Procedures

Principles of Endovascular Stent graft
 Rationale of stent-graft Rx is 2-fold:
~ in the acute phase: prevents imminent aortic rupture & relieve dynamic branch-vessel
occlusion
~ in the chronic phase: promote thrombosis of the false lumen & decrease morbidity
associated with patency of the false lumen: aneurysmal dilation, late aortic rupture & late
mortality
 Ability to cover the primary intimal tear & create a seal to stop the flow of blood entering the
false lumen & prevent the transmission of systemic pressure across the major intimal defect

‘COMPLICATED’ TYPE B AD
 If anatomy suitable – Endovascular preferred over surgery
 No randomized trial – but long term registries show lower mortality than surgical
series

UNCOMPLICATED TYPE B AD
 Apart from best medical Mx – endovascular Mx has been tried
 Rationale – To promote Aortic positive remodeling – thinking it would improve
survival
 Compared in 3 randomised trials
 Remains a controversy!

 Adsorb trial
 Instead and instead XL
 Petticoat - Stable trial, petticoat review, modified petticoat
 Hybrid approach

Suitable anatomy is pre-requisite
 Adequate access - Iliofemoral anatomy
 CFA MC access - MC right CFA for device delivery (Right EIA bifurcates at less acute angle from CIA)
- left CFA for diagnostic angiography guide catheters to guide deployment
- But not universal, needs individual assessment by imaging
- 20-24 Fr system MC
 Ideal access - lumen 8 mm or more - females have lower caliber arteries
- lowest diameter at proximal EIA
- no heavy calcified plaque – hinders device delivery
- no substantial tortuosity
- atleast one side iliofemoral artery non-dissected
 If EIA/femoral anatomy inadequate - CIA access by ileal conduit
- rarely, Distal aortic access – entire ilial system is hostile
Rutherford’s vascular surgery. 8th Ed. 2014

 Adequate aortic channel
 Abdominal aorta less often a problem
 Proximal descending thoracic aorta may have tortuous angle specially when aneurysmal – excessive sheath bending
 Severe arch angulation (>60 degrees)

 Aortic sealing zones
 Adequate proximal and distal landing zones
 Adequate lengths vary from 15-30 mm for various devices
 Longer sealing zones preferable - esp. in angulated areas
- decrease late endoleaks
- decrease late aneurysmal degeneration
 But, this urge to cover more aorta - increased risk of spinal cord ischemia/paraplegia
 Landing zone in curved parts – inner curve susceptible to leaks, as graft stiffness straightens it
 Free of significant disease
 “correct” device dimension: diameter based on non-diseased aorta immediately proximal to the entry tear: the segment between Left CC & Left
SCA is used: oversized by 10% to ensure secure anchoring & a tight circumferential seal
 If possible, ideal landing zone in TBAAD – Zone 3/4 proximally (after LSCA) and Zone 5 distally (before celiac trunk)

11 Landing zones
for aortic
interventions

 Adequate device dimension
 Diameter based on non-diseased aorta immediately proximal to the entry tear:
 MC segment between Left CC & Left SCA is used
 Oversized by 10% to ensure secure anchoring & a tight circumferential seal

STENT GRAFT SYSTEMS
 All thoracic stent-grafts have a metallic
skeleton with a covering membrane (either
PTFE or polyester).
 Most have either proximal or distal
uncovered stents for better stent-graft
anchoring to the aortic wall, and some also
have metallic barbs for the same purpose.
 are all self-expanding and constrained by a
sleeve or sheath.

STENT GRAFT SYSTEMS
Zenith TX2 by Cook Medical (A)
TAG by GORE (B)
Valiant by Medtronic AVE (C)
Relay Thoracic Stent-Graft by Bolton Medical
(D)
EndoFit by LeMaitre Vascular (E)

PROCEDURE
 Vascular access is preferably gained through surgical exposure of the right
common femoral artery. If the femoral arteries are too small or diseased, the
common iliac artery or abdominal aorta via a retroperitoneal approach can be
used
 Whenever those vascular accesses are considered inappropriate, anterograde
access through the ascending aorta by direct exposure via median
sternotomy can be achieved.

PROCEDURE
 Vascular access is preferably gained through surgical exposure of the right common
femoral artery. If the femoral arteries are too small or diseased, the common iliac artery
or abdominal aorta via a retroperitoneal approach can be used
 Whenever those vascular accesses are considered inappropriate, anterograde access
through the ascending aorta by direct exposure via median sternotomy can be
achieved.

PROCEDURE
 Initial Preparation - An angiography catheter is inserted through the right
brachial artery
 When the lesion is too close to the LSA, an additional catheter is advanced in the
ascending aorta via a percutaneous left brachial approach and is used as an adequate
landmark for the LSA origin for delivery.

PROCEDURE
Delivery of the Stent-Graft
 A hydrophilic guidewire is placed in the aortic arch under fluoroscopic guidance.
 exchanged for a stiff guidewire.
 intravenous administration of 5000 IU of heparin sodium
 the delivery system is passed over the stiff guidewire and positioned at the proximal end of the aortic
abnormality.
 The exact placement site is selected on the basis of angiographic and transesophageal echocardiography
information, considering aortic wall status and diameter at the neck sites.

PROCEDURE
Deployment of the Stent-Graft
 For optimal fixation, all stent-grafts are oversized in diameter compared with the diameter of the
proximal and distal necks of the lesion, by 10%–15%
 delivered either by holding the stent-graft stationary with a pusher rod while withdrawing the delivery
sheath or by pulling a string that releases the stent-graft– covering sleeve.
 demonstrate no significant shortening during or after deployment.

PROCEDURE
 Once the desired location is reached, the outer sheath is withdrawn to completely deploy the stent-graft.
 During release of the device, the systolic arterial blood pressure is lowered to 70 mm Hg. If
needed, a balloon catheter can then be inflated to achieve full expansion and to anchor the stent to the
aortic wall. Additional segments may be deployed distally as necessary to ensure disease exclusion.
 Completion angiography is performed to confirm proper stent-graft placement and complete disease
exclusion and to verify the presence of correct perfusion through the graft without perigraft leakage.
 No further anticoagulation is administered.

Complications
Early adverse events
 Paraplegia (1-5%)
 Stroke
 Retrograde dissection into the
ascending aorta (2%)
 Stent-graft collapse (3%)
 Periprocedural endoleaks
(<10%): mostly type I
Late adverse events
 Endoleaks (<5%): mostly type II
 Retrograde dissection into the
ascending aorta (2%)
 Stent-graft migration/torsion
 Strut fracture or erosion
 Aortic aneurysm formation &
rupture
 Aorto-oesophageal fistula
 Mobile thrombus within the stent-
graft lumen

Endoleaks
 Coined by White, et al, 1996
 Leak around proximal or distal attachment sites
 Persistent flow in aneurysm sac
 Incomplete exclusion
 Rates
 0 to 44%
 Risks
 Aneurysm Expansion
 Rupture

Endoleak
Classification
(Veith et al)

Endoleak management
 Type I and Type III endoleaks - regarded as treatment failures
o Warrant further treatment to prevent the continuing risk of rupture – Class I indication
o MC endovascular stenting – MC covered graft
 Type II endoleaks – usually conservative Management
o ‘wait-and-watch’ strategy to detect aneurysmal expansion, except for supra-aortic arteries
 Types IV and V endoleaks – usually benign course
o Treatment is required in cases of aneurysm expansion.

Outcome
 The IRAD registry provides an analysis of the different management options for type B aortic
dissection, with data comparing the impact on survival of different treatment strategies in 571
patients with acute type B aortic dissection
 390 patients (68.3%) with uncomplicated aortic dissection were treated medically, whereas among
complicated cases, 59 (10.3%) underwent standard open surgery and 66 (11.6%) underwent
endovascular repair.
 TEVAR provided better outcomes, with 9.3% mortality in patients treated with a stent graft and
33.9% mortality in patients who underwent open surgery.
 In patients discharged to home, longterm results seem to confirm the benefit of stent graft repair
with respect to medical therapy alone.

Outcome
Procedural success: 89%
Periprocedural endoleak: 6.7%
Neurologic complications: 2.3%
30-day mortality rate: 8.4%
One year data was available for 67 pts
Late intervention :1.5%
Late endoleak: 1.5%
Late death: 1.5%
1-year cumulative survival rate:90%

PETTICOAT
concept!
 Entry point is sealed with
endograft
 Remaining thoracic and
potentially abdominal
aorta is stented open
 Decrease chance of true
lumen collapse, enhance
aortic remodeling, and
promote false lumen
thrombosis

MANAGEMENT
TYPE A AD
(Endovascular)

Endovascular management of Aortic Dissection

Endovascular management of Aortic Dissection

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