Type B Aortic DissectionsFlorida Vascular Society

2019

Ravi K. Veeraswamy, MD

Professor and Chief, Division of Vascular Surgery

The Medical University of South Carolina

Charleston, SC USA

DISCLOSURES

• Consultant/Speaker• Cook, Inc

• W.L.Gore, Inc

• Medtronic, Inc

• Medical Advisory Board• Boston Scientific

▪ 10-15 cases/100,000 adults/year

▪ 10-12,000 new cases yearly

▪ 2/3 type A, 1/3 type B

▪ Acute type B

▪ 30% complicated, uncomplicated 70%

▪ Acute Aortic Syndrome

▪ AD, IMH, PAU

Aortic Dissection (USA)

Classification System

• Anatomic

• Temporal

• Acute (<14 days)

• Sub-Acute (14 days-3 months)

• Chronic (> 3months)

• Physiologic

• Uncomplicated

• Complicated

Uncomplicated Dissections: INSTEAD and INSTEAD XL

Management of Uncomplicated Type B Aortic Dissection

2-Year and 5-Year Results of the Randomized

Investigation of Stent Grafts in Aortic Dissection Trial

• Characterize short-term and long-term outcomes and vessel morphology of uncomplicated, TBAD patients treated with OMT vs OMT+TEVAR

• 7 European Centers, 2002 – 2005

• N = 140 subjects, OMT = 68, OMT+TEVAR = 72. 2 year and 5 year follow-up

• Primary Endpoint: All-cause mortality

• Secondary Endpoints: Aorta-specific mortality and disease progression

TEVAR placed acutely appears to offer an advantage at longer time points

• controversial data

• crossover rate

• underpowered study

Circ Cardiovasc Interv August 2013

INSTEAD XL: Key Results

TEVAR FOR AORTIC DISSECTIONPREVENTS LATE EXPANSION; ENCOURAGES AORTIC REMODELING

0%

10%

20%

30%

40%

50%

All-Cause Mortalityp=0.13

Aorta-Specific Mortalityp=0.04

Disease Progressionp=0.04

OMT n=68

TEVAR+OMTn=72

Cumulative Clinical Results: Year 0 through Year 5

19.3% 19.3%

46.1%

11.1%

27.0%

19.1%Absolute Risk

Reduction

12.4%Absolute Risk

Reduction

6.9%

8.2%Absolute Risk

Reduction

INSTEAD XL: Conclusions

• INSTEAD XL demonstrates:

• Elective TEVAR results in favorable aortic remodeling and long-term survival

• Reinterventions were low and clustered in first year

• TEVAR prevents late expansion and malperfusion and encourages aortic remodeling

• TEVAR associated with improved 5-year aortic-specific survival and delayed aortic disease progression

TEVAR in Uncomplicated Dissections

What’s Complicated?

▪ Rupture

▪ Malperfusion

▪ Rapid diameter expansion of thoracic aorta (>4.0cm total diameter)

▪ Unrelenting pain

▪ Uncontrolled HTN

▪ Extension of dissection

Contemporary Results of TEVAR for acute complicated Type B Dissections

• Low mortality• 3.9% in-hospital

• 5.8% one year

• Stroke rates• 3.9%

• No paraplegia

• False lumen thrombosis• 81% proximal thoracic aorta

• 77% mid thoracic aorta

• 33% hiatus

• True lumen expansion

• Low mortality• 2-9% in-hospital

• Stroke rates• 9%

• 6% paraplegia

Contemporary Results of TEVAR for acute complicated Type B Dissections

Tsai T, Evangelista A, Nienaber C et al., N Engl J Med. 2007 Jul 26;357(4):349-59

31.6%

mortality

@ 3 years

22.6%

mortality

@ 3 years

Predictors of Late Aortic Events

Predictors of Late Aortic Events

• Maximal aortic diameter ≥ 4.0cm at 1st CT scan

• IMH with localized PAU in proximal DTA

• ≥ 22mm false lumen

• Large entry tear (>10mm)

Van Bogerijan, et al. JVS. 2014;59:1134-43; Codner et al. JVS. 2019:69

• Recurrent/refractory pain or HTN

• Primary entry tear on aortic inner curve

• Distance from LSA

• Zone 3

Recent Criteria…

• Partial false lumen thrombosis Tsai T, NEJM 2007

• Focal FDG-uptake (inflammation) Sakalihasan N, p.c.

• Ongoing episodes of pain Trimarchi S, Circ 2010

• Intractable hypertension Evangelista A, Circ 2012

• Large entry size (> 10-15 mm) IRAD, Circ 2010

Classic Criteria for complicated type B dissection:

• Total aortic diameter ≥ 5.5 mm Elefteriade 2002, Ann

Thoracic Surgery

• Malperfusion Syndromes Nienaber 2011, JVS

• Impending rupture (extraaortic blood) Davies 2002, Annals of

thoracic surgery

• Early false lumen expansion Song 2007, JACC

Current Literature 2012

What is left as uncomplicated dissection?

Predictors of Late Aortic Events

TEVAR for Chronic Type B Dissections

• 51 patients

• Follow-up27 months

• Diameter Reduction

6cm to 5.2cm

• Meta-analysis• 1081 open surgeries

• 1397 TEVAR

• 61 B/FEVAR

• TEVAR and B/FEVAR with fewer serious adverse events

TEVAR for Chronic Type B Dissections

PLoS One. 2016 May 4;11(5)

Chronic Dissections after TEVAR

Ruddy et al Annal of Vasc Surg. 2014

• Significant Issue • After Open Type A

• After Acute Type B

• Open Surgery Has High Morbidity

• Role of TEVAR Being Defined

• Hybrid Approaches are Common

• ’Total’ Endovascular Solutions Are Coming

• Predictors of ‘At Risk” Dissections Needed

TEVAR for Chronic Type B Dissections

Why Has This Been a Struggle?

Tsai et al, J VascSurg 2008

Cheng et al, J VascSurg 2013

Rudenick et al, J Vasc Surg 2013

Limitations:

Non-anatomic

Non-physiologic

Non-systematic

Aortic Dissection Model

Segmented aorta from patient CT Silicone aortic model

4D PCMR Imaging

• Gradient echo sequence sensitive to moving fluid

• Can be used to acquire fluid velocities throughout a volume

• Velocity encoding value of 80 cm/s chosen following vencselection study

Markl et al., J MRI 2012

Increased number of fenestrations results in reduced flow reversal

(reduced false lumen thrombosis)

Two Tears Three Tears Four Tears

A

B

C

D

E

Retrograde

(Towards Head)

Antegrade

(Towards Feet)

Blood Pressure Does Not Affect Flow Reversal or Flap Motion

Hemodynamic Consequences

• Dissection with mobile intimal flap subjected to pulsatile flow causes flow reversal not seen in normal aorta

• Increased Number of fenestrations decrease false lumen flow reversal

• Complex fluid structures develop at fenestration sites

Clinical Implications

• Covering fenestrations with TEVAR may promote increased false lumen thrombosis (cover from subclavian to celiac)

• Acutely- Do NOT control blood pressure “aggressively”• What is ‘best medical therapy’ for managing acute Type B

dissections?

Conclusions

• Global evidence is evolving

• TEVAR data supports survival advantage – as long as

you can minimize the risk with early intervention

• High-risk groups are being better defined

• “Look for reasons to treat” as opposed to “look for

reasons not to treat”.

34 Presentation Title (Edit on Slide Master) | June 1, 2015 | Confidential, for Internal Use Only

TEVAR Rx of Acute Type B Aortic Dissection:

Important technical principles

▪ Measure aorta above dissection at LSA or Z-2

▪ Minimal or no graft oversizing <10%

▪ Cover PET plus 15-20 cm of the TL in the DTA

▪ Avoid post-ballooning

▪ Avoid hypertension during procedure

▪ Utmost gentleness in all endovascular maneuvers

Case 1

• 43 year old African American man presents with acute back pain and hypertension.

• HTN, pain persist despite HTN control

• CR elevated to 2.5 from baseline 1.0

CASE 2

• 39 Year old African American man, transferred with Type B dissection and acute R LE ischemia.

• HTN

• + Meth, Cocaine

• No pulses R LE

• CR 2.0