Aortic dissection surgery

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]; Aarti Narayan, M.B.B.S [3]; Hardik Patel, M.D.; Hibatullah Abdul Aleem, M.B.B.S[4]

The surgical and endovascular management of aortic dissection is determined by the type of dissection, the presence of complications, and patient-specific anatomy and risk. Acute type A aortic dissection is a surgical emergency; medical management alone carries a mortality of approximately 57% compared with 18% with surgical repair in contemporary registry data. Urgent surgical repair is recommended for all patients with suspected or confirmed acute type A dissection. Transfer to a high-volume aortic center is reasonable for stable patients. Type B aortic dissection is managed medically in the uncomplicated setting. Complicated type B dissection — defined by rupture, branch artery malperfusion, progressive aortic enlargement, intractable pain, or refractory hypertension — requires intervention, with endovascular stent grafting (TEVAR) preferred over open repair when anatomy is suitable. Preemptive TEVAR for uncomplicated type B dissection with high-risk anatomic features is supported by a Class IIb recommendation (2022 ACC/AHA) and upgraded to Class IIa in the subacute phase by the 2024 EACTS/STS Guidelines. Intramural hematoma (IMH) involving the ascending aorta is managed surgically; type B IMH is managed medically with selective endovascular repair for high-risk features or unfavorable anatomy.

Acute type A aortic dissection is a surgical emergency.^[1] IRAD data demonstrate surgical mortality declining from 25% to 18% over two decades, while in-hospital mortality with medical management alone remains approximately 57%.^[2] Among patients with intended surgical treatment, 48-hour mortality approximates 0.09% per hour; among medically managed patients, the corresponding rate approximates 0.5% per hour, a difference that includes the approximately 1% who die before reaching the operating room in the surgical group.^[3]

Nonhemorrhagic stroke complicating acute type A dissection is not a contraindication to surgery; surgical intervention is reasonable to reduce mortality and improve neurologic outcomes. Acute hemorrhagic stroke is a relative contraindication due to the necessity of intraoperative heparinization.

Risk factors associated with higher surgical mortality include tamponade, shock, neurologic or visceral malperfusion, and preoperative myocardial ischemia. Even elderly patients benefit from surgery over medical management; circulatory collapse is the primary predictor of long-term survival.

• When the aortic root is partially dissected but aortic valve leaflets are structurally intact, aortic valve resuspension is recommended over valve replacement (Class I, LOE B-NR). Algorithmic use of resuspension as the preferred strategy yields operative mortality as low as 8.1%.
• When there is extensive root destruction, a root aneurysm, or a known genetic aortic disorder, aortic root replacement with a mechanical or biological valved conduit is recommended (Class I, LOE B-NR).
• Valve-sparing root repair (VSRR) may be reasonable in selected stable patients when performed by experienced surgeons in a Multidisciplinary Aortic Team (Class IIb, LOE C-LD).^[1]

• An open distal anastomosis (without aortic cross-clamping during circulatory arrest) is recommended to improve survival and increase false lumen thrombosis rates (Class I, LOE B-NR).^[1]
• Hemiarch repair is recommended over more extensive arch replacement when no intimal tear in the arch and no significant arch aneurysm is present (Class I, LOE B-NR).
• Extended aortic repair with antegrade stenting of the proximal descending thoracic aorta (frozen elephant trunk, FET) may be considered when the dissection flap extends through the arch into the descending aorta, to treat malperfusion and reduce late distal aortic complications (Class IIb, LOE C-LD).^[1]

The 2024 EACTS/STS Guidelines recommend a tear-oriented approach with exclusion or resection of the primary entry tear (Class I, LOE B) and state that inspection and coverage of communications between lumina in the proximal descending aorta may be considered in specialized centers (Class IIb, LOE C).^[4]

Per the 2022 ACC/AHA Guideline, the FET stent length should be less than 15 cm and coverage should not extend to T8, to avoid spinal cord ischaemia.^[1] Delayed spinal cord ischaemia may occur up to 2 weeks after surgery, and delayed paraplegia accounts for nearly 60% of all spinal cord deficits encountered; early recognition and treatment with blood pressure augmentation and CSF drainage remain critical.^[1]

• Axillary cannulation is reasonable over femoral cannulation to reduce the risk of stroke or retrograde malperfusion when feasible (Class IIa, LOE B-NR). The 2024 EACTS/STS Guidelines similarly recommend antegrade systemic perfusion via axillary or direct aortic cannulation (Class IIa, LOE B).^[1][4]
• Selective antegrade cerebral perfusion during circulatory arrest is reasonable to improve neurologic outcomes (Class IIa, LOE B-NR).
• Direct aortic or innominate artery cannulation with imaging guidance is reasonable as an alternative to femoral or axillary cannulation (Class IIa, LOE B-NR).^[1]

Imaging evidence of malperfusion is present in up to 25% of patients with acute type A dissection. Clinical malperfusion syndrome carries a mortality of 30.5% versus 6.2% without malperfusion, and mortality correlates with the number of malperfused organs.^[1]

• For renal, mesenteric, or lower extremity malperfusion: immediate operative repair of the ascending aorta is recommended (Class I, LOE B-NR). Residual malperfusion should be assessed postoperatively with secondary endovascular or surgical interventions as needed.
• For clinically significant mesenteric (celiac, SMA) malperfusion: either immediate ascending aortic repair or immediate mesenteric revascularization (endovascular or open) before ascending aortic repair is reasonable (Class IIa, LOE C-LD).^[1]

Mesenteric malperfusion carries mortality exceeding 63%; untreated, IRAD data show in-hospital mortality of 95%. A hybrid operating room with endovascular capability is ideal for centers managing this complication.

Medical therapy is recommended as the initial management strategy for all patients with uncomplicated acute type B dissection (Class I, LOE B-NR).

Intervention is recommended for complicated acute type B dissection (Class I, LOE C-LD). Complications include rupture, branch artery occlusion with malperfusion, extension of dissection, progressive aortic enlargement, intractable pain, and refractory hypertension.^[1]

• The 2024 EACTS/STS Guidelines provide a Class I, LOE B recommendation: in any TEVAR involving zone 2, left subclavian artery revascularization is recommended to reduce the risk of neurologic complications including stroke and spinal cord ischaemia.^[4] This applies regardless of whether the TEVAR is performed for dissection, aneurysm, or other indications, and should be planned prospectively when zone 2 coverage is anticipated.
• For other complications with suitable anatomy: endovascular approaches are reasonable over open repair (Class IIa, LOE C-LD).
• The 2024 EACTS/STS Guidelines similarly recommend TEVAR for complicated acute type B dissection with suitable anatomy (Class I, LOE B) and FET repair when TEVAR anatomy is unsuitable (Class IIa, LOE B).^[4]

Endovascular management may be considered for uncomplicated acute type B dissection with high-risk anatomic features (2022 ACC/AHA: Class IIb, LOE B-R; 2024 EACTS/STS: Class IIa for the subacute phase).^[1][4]

High-risk imaging features (2022 ACC/AHA Table 28) include:

• Maximal aortic diameter >40 mm
• False lumen diameter >20–22 mm
• Entry tear >10 mm
• Entry tear on the lesser curvature of the aortic arch
• Increase in total aortic diameter >5 mm between serial imaging studies
• Bloody pleural effusion
• Imaging-only evidence of malperfusion

High-risk clinical features include refractory hypertension despite three or more antihypertensive classes at maximal doses, refractory pain persisting beyond 12 hours, and readmission.^[1]

The 2022 STS/AATS Guidelines recommend open surgical repair as more durable than TEVAR in patients with connective tissue disorders (such as Marfan syndrome or Loeys-Dietz syndrome) who have type B dissection with disease progression despite optimal medical therapy (OMT).^[5] TEVAR may be considered in the emergency setting or as a bridge.

Indications for elective intervention include aneurysmal dilation (total diameter ≥55–60 mm), rate of diameter growth >10 mm/year, or symptoms. The 2022 ACC/AHA Guideline recommends elective thoracic aortic repair for chronic residual dissection with total aortic diameter ≥5.5 cm (Class I, LOE B-NR).^[1]

• Open surgical repair should be considered for chronic type B dissection with indications for intervention unless comorbidities are prohibitive (STS/AATS Class I).^[5]
• TEVAR is reasonable for chronic type B dissection with suitable anatomy in patients at high surgical risk due to comorbidities (STS/AATS Class IIa).^[5]

• Complicated acute type A or type B IMH: urgent repair is recommended (Class I, LOE B-NR).
• Uncomplicated acute type A IMH: prompt open surgical repair is recommended (Class I, LOE B-NR).
• In selected patients with uncomplicated acute type A IMH at increased operative risk without high-risk imaging features, an expectant medical approach may be considered (Class IIb, LOE C-LD).
• Uncomplicated acute type B IMH: medical therapy as the initial management strategy is recommended (Class I, LOE B-NR).
• Type B IMH requiring repair in zones 2–5 with favorable anatomy: endovascular repair is reasonable (Class IIa, LOE C-LD).
• Uncomplicated type B IMH with high-risk imaging features: intervention may be reasonable (Class IIb, LOE C-LD).^[1]

Abbreviations: AAS = acute aortic syndrome; CTA = computed tomography angiography; MRI = magnetic resonance imaging; TEVAR = thoracic endovascular aortic repair; HTN = hypertension; SBP = systolic blood pressure; HR = heart rate; IV beta-blocker = intravenous beta-adrenergic blocking agent; OMT = optimal medical therapy; LSA = left subclavian artery; FL = false lumen; FET = frozen elephant trunk; LSA revascularisation = left subclavian artery revascularisation; LOE = level of evidence; EACTS = European Association for Cardio-Thoracic Surgery; STS = Society of Thoracic Surgeons

Brain protection is a key element of ascending and arch aortic repair. Deep hypothermic circulatory arrest, selective antegrade cerebral perfusion, and retrograde cerebral perfusion alone or in combination are reasonable to minimize brain injury; institutional experience guides technique selection. Perioperative brain hyperthermia should be avoided.^[1]

Cerebrospinal fluid drainage is recommended for patients at high risk of spinal cord ischemic injury during open and endovascular thoracic aortic repair. Spinal cord perfusion pressure optimization with proximal aortic pressure maintenance and distal aortic perfusion is reasonable. Moderate systemic hypothermia is reasonable for open descending aortic repairs. Early detection and treatment of SCI with blood pressure augmentation and CSF drainage enables complete neurologic recovery in the majority of patients.^[10]

Transesophageal echocardiography is reasonable in all open surgical repairs of the thoracic aorta and in endovascular procedures for monitoring, procedural guidance, and endoleak detection.^[1]

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