Thoracic Aortic Aneurysm and TEVAR

23.1Descending thoracic aortic aneurysm: who needs repair

The first decision in descending thoracic aortic aneurysm care is whether the aneurysm has reached repair. In the standard-risk patient the contemporary society documents place the elective threshold near 5.5 to 6.0 cm; ACC/AHA 2022 ACC/AHA 2022 and ESVS 2017 Editor's Choice Management 2017 use the 5.5–6.0 cm band while ESC 2014 ESC 2014 typically used 6.0 cm, and all three documents downshift the threshold for genetic aortopathies (Marfan, Loeys-Dietz, vascular Ehlers-Danlos), rapid growth, saccular morphology, family history of dissection, and symptomatic disease. The diameter number itself reflects the rupture and dissection risk curve, which rises steeply above 6.0 cm in pooled aortic-disease series; below 5.5 cm the annual event rate in a true standard-risk patient is low enough that the periprocedural risk of repair usually exceeds the rupture risk of surveillance, and that calculus inverts as the aneurysm grows.

The threshold should be applied as a clinical judgment, not as a single number. Symptomatic disease — back pain that maps to the aneurysm, new hoarseness, embolic events — is itself an indication for repair regardless of diameter, because symptomatic aneurysms behave like impending complications rather than like stable disease. Rapid growth on serial imaging is treated by most teams as an indication independent of absolute diameter, and saccular morphology, which concentrates wall stress, is given similar weight. In the genetic-aortopathy population the specific class/level wording differs by society and remains a verification target rather than a memorised cut-off, so the chart should record the patient's syndrome, family history, and the specific guideline framework being applied.

23.2Thoracic endovascular vs open repair

Thoracic endovascular aortic repair (TEVAR) deploys a stent graft across the descending thoracic aorta to exclude the aneurysm from the circulation and remodel the wall onto the device. The original comparative evidence base is now mature. The Makaroun 2008 long-term outcomes from the TAG investigators Gore TAG 5-year results 2008 and the Cheng 2010 pooled review Cheng TEVAR vs open meta-analysis 2010 remain the reference comparisons that shaped contemporary practice: pooled series generally show lower 30-day mortality and shorter hospital stay with TEVAR than with open repair, with broadly comparable mid-term aneurysm-related survival, while long-term outcomes are dominated by seal-zone integrity and reintervention for endoleak or device migration rather than by aneurysm-related death.

For an individual patient the decision is rarely binary. The pooled signal favours TEVAR for older patients, for patients whose anatomy and physiology fit the device, and for those whose perioperative reserve makes a thoracotomy a high-risk proposition. Open repair retains a role for younger fit patients with hostile endovascular anatomy, for patients with connective-tissue disease in whom an endovascular seal in a fragile aorta is unlikely to remain durable, for arch-involvement that exceeds branched-device capability at the local center, and for chronic dissection anatomy in which a thoracoabdominal extent will eventually need replacement anyway. Center experience is real and should be discussed openly with the patient: high-volume aortic centers show better risk-adjusted outcomes than low-volume ones for both TEVAR and open thoracic repair, and the volume effect is most visible for the difficult anatomy at the margins of the pooled trials.

The access-strategy conversation is part of the operative plan rather than a same-day decision. Sex- and age-specific anatomy matters: older patients and women more often have small or calcified iliac access, and the team should decide in advance whether femoral cut-down, an iliac conduit, or percutaneous closure with a large-bore device will be used. Operative timing should also be made explicit, particularly for symptomatic disease where a several-day delay for full work-up may be acceptable while overt rupture or contained leak demands immediate transfer. The mid-term durability picture should be carried into the consent conversation: the patient who chooses TEVAR is also choosing the surveillance ladder that follows, and acceptance of lifelong imaging and possible reintervention is part of the consent.

23.3Left subclavian artery coverage and revascularization

Most thoracic stent grafts that achieve a durable proximal seal in the standard descending-aorta landing zone need to cover the left subclavian artery origin. Coverage is generally well tolerated when there is no dominant left vertebral flow, no patent left internal mammary coronary graft, no hypoplastic or absent right vertebral, no left-arm haemodialysis access dependence, and the coverage length does not push spinal cord perfusion into a marginal zone. Where any of those features is present, society guidance recommends planned revascularization before or with the TEVAR — either carotid-subclavian bypass or left subclavian-to-common-carotid transposition ACC/AHA 2022 · Editor's Choice Management 2017 · Open aortic surgery 2016 · Descending thoracic aortic 2005.

Carotid-subclavian bypass is the most common revascularization technique. It is well tolerated when performed under local or regional anesthesia by an experienced team; a small-diameter prosthetic graft is the typical conduit and the proximal subclavian stump is then ligated or coil-occluded to prevent type II endoleak from retrograde flow. Transposition — direct reimplantation of the left subclavian onto the common carotid — avoids a prosthetic interposition graft, has the durability profile of a native-to-native anastomosis, and is preferred when patient anatomy and operator experience allow. The staging question (revascularization first as a separate operation, or concurrent revascularization on the day of TEVAR) is center-specific; staging may reduce single-procedure physiological stress in fragile patients, while a same-session approach shortens the overall pathway and is preferred when access logistics allow.

Emergent settings often force coverage without revascularization. The patient and team should be explicit about the deferred stroke risk, the left-arm claudication and ischemic-pain risk, and the plan to revascularize once stabilised. Branched and fenestrated thoracic devices that preserve subclavian flow without an extra-anatomic bypass are an emerging option that should be mentioned in the consent discussion as a reasonable alternative at centers with custom-device experience, and they are likely to shift this decision over the next decade. A pragmatic decision rule is therefore: assume coverage will be needed at the planned proximal landing zone, check the four anatomic and physiologic risk features explicitly, and have an elective revascularization plan ready before the operative day rather than after.

23.4Spinal cord protection and retrograde type A dissection

Spinal cord ischemia is the complication that defines extensive TEVAR and that distinguishes a technically successful procedure from a life-altering one. The mechanism is collateral collapse: when long segments of intercostal arteries are covered without sufficient lumbar, subclavian, hypogastric, and pelvic collateral network reserve, the cord falls below its perfusion threshold and can infarct hours or even days after the procedure. Risk rises with the length of aortic coverage, with prior abdominal or descending repair that has already disrupted collaterals, with low intraoperative blood pressure, and with any condition that limits collateral reserve (severe atherosclerosis of the pelvic vessels, prior hypogastric occlusion, prior left subclavian coverage without revascularization).

Layered protection is the standard at high-volume centers. Cerebrospinal fluid drainage lowers spinal canal pressure and widens the cord perfusion gradient; permissive hypertension preserves collateral perfusion during the highest-risk window; staged repair, where anatomy and physiology allow, gives the collateral network time to expand before the next coverage; and prompt neurological assessment in the immediate postoperative period allows perfusion targets, drainage, and oxygen delivery to be escalated at the first sign of deficit Editor's Choice Management 2017. Drainage carries its own bleeding and catheter-related risk; the routine-versus-selective drainage choice is center-specific and should be a written local protocol rather than an ad hoc decision in the operating room.

Retrograde type A dissection is a separate, less common, but high-mortality complication of TEVAR. The intimal tear arises in the ascending aorta, usually at the proximal stent edge, and propagates retrograde from a landing zone that is too proximal, oversized, or aggressively ballooned. The known risk factors are proximal landing in the arch (especially zone 0 and 1), aggressive proximal oversizing, post-deployment ballooning over a fragile arch, and underlying aortic fragility from a genetic aortopathy or chronic dissection. The avoidance strategies follow directly: conservative device oversizing (favouring the lower end of the manufacturer-recommended range over the upper end), elimination of unnecessary proximal ballooning, careful attention to aortic-wall fragility, and a low threshold for open repair when the proximal arch is the dominant lesion or when an endovascular seal would require a hostile zone-0/zone-1 landing in a fragile patient Editor's Choice Management 2017 · Retrograde Type Aortic 2017 · Open aortic surgery 2016 · Endovascular Repair 2015 · Retrograde aortic dissection 2014.

23.5Post-TEVAR imaging surveillance

Surveillance after TEVAR follows a structured cadence rather than a fixed interval: society guidance places the first cross-sectional study at 1 month, the second at 6 months, the third at 12 months, and then annually for the life of the device ACC/AHA 2022 · Editor's Choice Management 2017 · Gore TAG 5-year results 2008 · Thoracic stent graft 2016. The cadence is modified by what the studies show. A stable graft with a shrinking or stable sac at 12 months can usually move to longer intervals — many programs step to 18-month then 24-month studies once a stable mid-term picture is documented — while an unstable seal, a type Ia endoleak, distal sac growth, or a new endoleak finding shortens the next study and triggers a reintervention conversation rather than another routine follow-up.

The modality is usually contrast-enhanced CT angiography because it answers the largest number of questions in one study: sac diameter, endoleak presence and type, device position, branch patency, and any new aortic disease. MR angiography and non-contrast techniques are useful adjuncts for the patient with renal impairment, a contrast allergy, or a long expected lifespan in whom cumulative radiation matters; gated cardiac imaging is being used at some centers to reduce motion artefact at the arch and to better resolve early proximal endoleak. The surveillance plan should be agreed and documented before discharge: the patient should know when their next study is due, where it will be performed, and which team is responsible for reading and acting on it, because lost-to-follow-up is the single most common preventable cause of late TEVAR failure.