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“Medical Therapy” for Acute Type B Aortic Dissections is not ideal • False lumen thrombosis • unpredictable • Long-term stabilization of septum • No assurance to prevent risk of di

Subacute thoracic aortic dissection: When and how to perform TEVAR ?

I-Hui Wu , MD, PhD

Clinical Assistant Professor

Division of Cardiovascular Surgery,

Department of Surgery National Taiwan University Hospital,

Taipei, Taiwan

Aortic Dissections: special considerations

Classification of aortic dissection

Anatomic Classification

Stanford Type A Stanford Type B

DeBakey

“Medical Therapy” for Acute Type B Aortic

Dissections is not ideal

• False lumen thrombosis

• unpredictable

• Long-term stabilization of

septum

• No assurance to prevent risk

of dissection and rupture

• 19% when intervention was required

• 8.3% when able to treat medically

Estrera et al Circulation 2006; 114: I-384-389

Procedural Goals of TEVAR in Type B dissection

 Coverage of primary entry tear

 Stabilize septum

 Re-establish perfusion to hypo-perfused / ischemic organs

 Aortic Remodeling

 15 patients with Type B dissections and 4 Type A— covered entry tear

 Branch vessel involvement in 14; seven patients

Acute vs Subacute vs Chronic Dissections

 What is different?

 The integrity and

plasticity of the aortic

wall?

 Can the true lumen be re

expanded….if so, at what

cost?

 How much coverage?

94%

63%

55%

Re-intervention

Uncomplicated Type B Aortic

Dissection

 Acute: ADSORB (Acute Dissection Stentgraft OR Best Medical Treatment) trial

 Chronic: the INSTEAD trial (Investigation of STEnt grafts in Acute Dissection) for dissections between

14 days and 1 year

 The VIRTUE Registry

Max True Lumen Diameter

Max False Lumen Diameter

Overall Transverse Diameter

Conclusion:

•Uncomplicated AD can be safely treated with the Gore TAG device

•Remodelling with thrombosis of the false lumen and

reduction of its diameter is induced by the stent graft, but long term results are needed

INSTEAD-XL Trial

Kaplan–Meier estimates of

all-cause mortality

Kaplan–Meier estimates of

aorta-specific mortality

Kaplan–Meier

estimates of a

combined end point

of progression and adverse events

(aorta-related death, conversion, and

ancillary interventions)

• prospective, nonrandomised, multicentre European Clinical Registry that enrolled 100 patients with type B aortic dissection treated with the Valiant (Medtronic) thoracic stent-graft

• Acute dissection (14 days from first dissection)

• Aortic rupture, malperfusion syndromes (visceral, renal, lower limb), impending rupture (persistent pain), refractory

hypertension

• Subacute dissection (15～92 days)

• complicated/symptomatic dissection, aortic expansion >5.5 cm, aortic diameter >4.0 cm with true and false lumens both patent

• Chronic dissection ( >92 days)

• complicated/symptomatic dissection, aortic diameter>5.5 cm or expanding>0.5 cm/year

All cause mortality

Dissection related mortality

Aortic re-intervention

True lumen area

False lumen area

False lumen thrombosis

Conclusions:

The principle clinical findings suggest that TEVR is able to provide good protection from aortic related death in the mid-term, but with a high rate

of aortic reintervention

Analysis of aortic morphology suggested that aortic remodelling in

subacute patients is similar to the acute group Retention of aortic

plasticity in the subacute group lengthens the therapeutic window for the treatment of uncomplicated type B dissection

• Aorta retained its plasticity after the classical 2-week

window had elapsed following onset of symptoms

 this is novel

 patients with sub-acute dissection may also benefit from

TEVR through aortic remodeling, thereby avoiding the risks of aneurysmal degeneration

• Low dissection related mortality following TEVR at 3 years

 it is still unknown whether TEVR offers similar protection

(from late aortic related mortality) as open surgery

• Relatively high rate of re-intervention at 3 years (especially

in the chronic dissection group

 8 out of 26 (31%) of patients with a chronic dissection required distal extension after their primary TEVR

JACC Vol.6 7, No.10, 2016 Mar 15, 2016:1254–60

Conclusion:

•Subacute patients

• gained better clinical results after TEVAR

• the dissecting intimal flap matures and stabilizes in the

subacute phase and would make the delivery of stent grafts safer

•Acute and Subacute patients

• exhibited greater aortic remodeling in any part of the aorta than the chronic

•With better clinical results and aortic remodeling, the

subacute phase (15 to 90 days) may be an optimal timing of TEVAR for those patients

• 102 patients were treated for

non-traumatic acute complicated type B dissection

• 22 patients undergoing TEVAR for an

acute dissection-related complication occurring >14 days (median time to TEVAR was 23 days (range, 15-85

days) after onset of symptoms

• In this subset of patients, median age was 58 years compared to

69 in those operated on within 14 days (p = 0.01)

• There were no early deaths or neurological complications among the 22 patients with acute complications after more than 14 days

• A significant proportion of patients presented with

acute complications requiring TEVAR 15-85 days

after onset of aortic dissection

• The distribution of complications occurring in the

sub-acute patients differed from those in patients

treated within < 14 days (p < 0.0001)

• There is a sub-acute, unstable phase in the transition

between acute and chronic dissection during which acute and life-threatening complications might occur

Conclusion

TEVAR in the subacute phase:

•Lower rate of perioperative complications compared

to acute phase

•aorta retained its plasticity after the classical 2- week

window had elapsed following onset of symptoms

•the low dissection related mortality following TEVR at

3 years

•the relatively low rate of re-intervention at 3 years

compared with chronic dissection group

Conclusion

• Is it safer to intervene in the sub-acute period?

• the acute and sub-acute groups are non-comparable

• Subacute group

• significantly younger

• different pathology

• a large proportion present with rapid aortic

dilatation rather than impending or actual aortic rupture or malperfusion

• If it is safer to intervene in the sub-acute phase,

would this influence a more aggressive policy of

re-intervention in the uncomplicated patients?

• the INSTEAD trial failed to demonstrate and advantage

for early intervention

However, Is there really a Subacute Phase ?

• Do sub-acute dissections behave in the long term in

a similar manner to acute dissections?

• significantly greater degrees of favourable aortic

remodelling in the acute dissection compared to chronic

• This should ultimately lead to improved long term

outcomes in terms or reintervention and aortic expansion

• Longer term data are clearly required to further guide

clinical practice

However, Is there really a Subacute Phase ?

Thank You Very Much For

Your Attention !!

When to treat acute ?

When to treat chronic

Surgical replacement of aorta

operation due to injured aortic wall

Outcome of surgical treatment

of acute dissection

 82 patients with acute dissection enrolled in

IRAD who required surgery (out of 476 patients)

from 1996-2003

 International Registry of Acute Aortic Dissection

represents consecutively studied patients from

18 aortic centers around the world

 In hospital mortality 29.3%

Trimarchi et al Circulation 2006; 114:I357-364

Acute type B dissection with rupture

Chronic type B dissection with

aneurysmal formation

Does TEVAR improve long term survival for chronic dissection?

WHAT IS KNOWN

• Short-term outcomes improve with endovascular management of complicated type B dissection

WHAT WE WANT TO KNOW

• In survivors of type B dissection, is TEVAR

associated with improved 5-year aorta-specific survival and delayed disease progression?

• In stable type B dissection with suitable anatomy, should TEVAR be considered to avoid late

complications

• Long-term outcomes of uncomplicated (initially stable) type B dissection subjected to TEVAR?

Typical chronic type B dissection

Chronic Dissection

Chronic Dissection: 3 years follow up

TEVAR

Jan 30, 07 / Post

Jan 30, 07 / Pre

Follow-up: 1 year and 3 year later

INSTEAD-XL Trial

Kaplan–Meier estimates of

all-cause mortality

Kaplan–Meier estimates of

aorta-specific mortality

Complications!

• Conformity to the arch knuckle

 Bird beak

• Oversizing with endograft collapse

• Retrograde type A dissection

• Endoleaks

Conformity…

*

Type B

Dissection w/ extreme

oversizing:

COLLAPSE !!

Modifications of Current Devices

Flexibility is KEY !

Device Attributes that Remain the Same

Endoprosthesis

Stent is nitinol, wound in a sinusoidal pattern

 ePTFE on luminal and abluminal surfaces

 Sutureless graft attachment

 Deployment mechanism

Sealing cuffs

 Delivery system

Enhancements

Expanded sizes and oversizing windows

 Designed to treat a broad range of anatomies and

etiologies

 Expanded oversizing of 6-33% allows treatment of

tapered aorta with a single straight device

 Able to treat thoracic aortas down to 16 mm

Optimized Stent Frame

Eliminated flared scallops Partially uncovered stents are designed to help achieve excellent wall apposition in angulated anatomy to seal

Increased wire diameter optimizes radial force to resist compression in high flow aortas

Nine apex pattern further distributes point load and contributes to adequate

fatigue life in maximum oversizing conditions

Optimized Stent Frame

Modified Stent Frame

 positioned at the leading end

of the graft material; at the

base of the partially

uncovered stent

 positioned at the trailing end

of graft material

 the trailing end of the device

is fully covered

Expanded Sizing and Oversizing Windows

 Expanded sizes for the Conformable GORE ® TAG ® Thoracic Endoprosthesis allow treatment of a broad range of vessel diameters (16–42 mm)

 includes small diameter, low-profile stent grafts for smaller aortic diameters

Acute type B dissection treated with C-Tag

Acute Complicated

Dissection Study

(TAG 08-01)

 the short-term safety and effectiveness of the

conformable GORE TAG Device in the treatment of acute complicated type b dissections of the DTA

 a non-randomized, multicenter study conduct

 minimum enrollment of 50 patients and a maximum

enrollment of 200 patients

 the primary safety endpoint of this study

 all-cause mortality incidence through 30 days

post-treatment

Results

•All device implants were successfully completed

•Six patients (12%) required additional device

implantations less than1 year from the index procedure

•no conversion to open repair at 1 year

•Exclusion of the primary entry tear at 30 days occurred

in 97.5% of patients

•All-cause mortality through 30 days was 8%

•Survival was 88% at 1 year and 85% at 2 years

Results

•At 1 year after treatment, 35.1% of patients had

experienced a decrease of 5 mm in overall diameter in the treated segment of the aorta

•30 days outcome

• Stroke rate: 18%

• none were fatal, and one permanent deficit

occurred

• Spinal cord ischemia: 8%

• without any permanent or significant deficits

•New aortic dissection (3 retrograde, 2 de novo) occurred

in five patients (10%)

•The secondary intervention rate was 18%

88% 85%

Conclusions

Treatment with the cTAG produced favorable

perioperative clinical and anatomic outcomes

 an operative mortality of 8% in this cohort is

comparable to that noted in a Society for Vascular Surgery objective performance criteria publication

 Late survival in our cohort compares favorably

with historical data referable to complicated type

B dissection

Retrograde type A dissectgion !

Device Ballooning for Dissection

 Caution must be taken when ballooning

distally – balloon can propagate entry site

• Uncomplicated Type B dissections are still largely

managed medically with β-blockers and nitrates

• Shift from open repair to TEVAR in most cases of

complicated aortic dissection

• High-risk uncomplicated subset of patients: larger

false lumen, larger primary tear, partial thrombosis of false lumen, uncontrolled hypertension

• Intervention (Endovascular or Surgical) is warranted for rapidly expanding false lumen, branch vessel

compromise or aneurysmal degeneration

• TEVAR offers improved 5-year morbidity and mortality

• Acute complicated patients

• Chronic complicated patients

Thank You Very Much For

Your Attention !!

• Do sub-acute dissections behave in the long term in

a similar manner to acute dissections?

• a number of studies have demonstrated significantly

greater degrees of favourable aortic remodelling in the acute dissection compared to chronic, with diminution

of the false lumen and re-expansion of the acute lumen

• This should ultimately lead to improved long term

outcomes in terms or reintervention and aortic expansion

• Longer term data are clearly required to further guide

clinical practice

However, Is there really a Subacute Phase ?

• Do sub-acute dissections behave in the long term in

a similar manner to acute dissections?

• a number of studies have demonstrated significantly

greater degrees of favourable aortic remodelling in the acute dissection compared to chronic, with diminution

of the false lumen and re-expansion of the acute lumen

• This should ultimately lead to improved long term

outcomes in terms or reintervention and aortic expansion

• Longer term data are clearly required to further guide

clinical practice

However, Is there really a Subacute Phase ?