In this episode, Yogi and Sam delve into discussing thoracic aortic stenting.

Podcast 26 - Thoracic Aortic Stenting

The first endovascular thoracic aneurysm repair was performed by Dale in 1994 - with the use of custom designed graft with a combination go Gianturco Z-stents and polyester fabric. It was not till 2005 that a commercially available thoracic graft became available

The introduction of TEVAR has added further dimensions to open surgery by creating treatment options not previously available in treating aortic dissection, thoracic and thoracoabdominal aneurysm and traumatic injury.

• In elderly patients, TEVAR has replaced open surgery and medical management for problems confined to the descending thoracic aorta 

Indications

• Aneurysmal disease (>5.5cm) - true degenerative aneurysms vs. post dissection aneurysms vs. mycotic vs. pseudo aneurysms (Zone 2)
• Complicated acute aortic syndromes
• Blunt thoracic aortic injury 
• Evolving techniques - management of dissection aneurysms in Zone 0/1

Approved Devices 

• Gore TAG Conformable Thoracic Stent Graft
• Medtronic Valiant Thoracic Stent Graft with Captivia Delivery System  
• Cook Zenith Alpha
• Endospan Nexus and Bolton
• Terumo Aortic Relay Device  

Pre-operative Considerations

How do we do it?

• General consideration - 
• vascular access, iliac vessel diameters
• For suitable iliac and femoral access vessels are required
• Small diameters <7mm, existing calcification and vessel tortuosity have a profound impact on the procedure especially if present in combination 
• The right femoral artery is typically favoured for device insertion, whereas the contralateral femoral artery is reserved for diagnostic imaging 
• An ideal access vessel should be >7mm in diameter to accommodate a 22Fr sheath and >8mm for a 24 Fr sheath 
• Alternate options - iliac conduits or endo-paving 
• Landing zone 
• General role >20mm of normal appearing aorta for an adequate seal zone - proximal and distal 
• Longer seal zones is considered adequate for most cases, longer seal zones are preferable in angulated aortic segments to decrease the occurrence of Type 1 end-leaks and device migrations 
• Anatomical boundaries include the left subclavian artery and the coeliac artery should be considered a
• Proximal and distal aortic diameters 
• Ishimaru’s Classification of Landing Zone 
• Coverage of the left subclavian artery is generally well tolerated because of a rich collateral network - however routine exclusion should be discouraged because experimental and clinical evidence suggest that not all patients tolerate the occlusion safely 
• The left subclavian artery is vital for perfusion of both the spinal cord and the brain via the left vertebral artery through the internal management and anterior intercostal branches 
• When left subclavian coverage is considered, pre-operative CTA imaging should assess latency of the right vertebral artery, connections to the Basilian artery and the COW in order to identify patients that may not tolerate left SCA occlusion 
• As we approach Zone 0,1 or sometimes in 2 supra-aortic debranching may be necessary 
• Open CTS vs. CCA-CCA-SCA, CCA- SCA, chimney stents 
• Imaging
• CTA with fine slices
• Sizing
• Overzealous device sizing is associated with graft infolding, gutter formation and aortic neck degeneration due to excessive radial force \
• Aortic diameters are measured with orthogonal reconstructions...