Acute aortic dissection: type A and type B

Overview and definitions

Acute aortic syndromes (AAS) are life-threatening emergencies.^[1] ESC 2024 says AAS include classic acute aortic dissection, IMH, PAU, aortic pseudo-aneurysm and traumatic aortic injury.^[1] ESC 2024 adds that these syndromes involve aortic wall damage and share a dynamic, overlapping pathophysiology, clinical presentation, and diagnostic and therapeutic approach.^[1] ACC/AHA 2022 describes AAS as conditions with a breach in the integrity of the aortic wall, the most common being aortic dissection, IMH and PAU, all of which can lead to rupture.^[2]

AAS may also be iatrogenic, after open or endovascular/percutaneous procedures or cardiac surgery (ESC 2024).^[1] This topic covers dissection, IMH and PAU.

Classification

The classifications below answer three questions: is the ascending aorta involved, where is the entry tear and how far does the dissection extend, and how long ago did symptoms start?^[1]

Anatomy: Stanford and DeBakey

ESC 2024 calls the Stanford and DeBakey systems the most widely used anatomical classifications.^[1] The Stanford system asks one question: is the ascending aorta involved?^[1]

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ESC 2024 maps the Stanford system onto DeBakey types: type A covers DeBakey types I and II, and type B covers DeBakey types IIIa and IIIb.^[1] ESC 2024 says the Stanford system considers prognostic as well as anatomical and treatment aspects, since patients with DeBakey type II AAS will probably be left without structural aortic wall lesions after surgery.^[1]

Timing

Timing classifications of aortic dissection

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ESC 2024 times AAS from symptom onset to diagnosis; the SVS/STS table in ACC/AHA 2022 uses time from onset of symptoms and is described there as the most contemporary system.^[1][2] Traditionally, dissection was called acute in the first 2 weeks after symptom onset and chronic beyond the second week (ACC/AHA 2022).^[2]

Entry tear, extent and malperfusion: newer systems

A newer classification records the entry tear site and the extent of the dissection, and ESC 2024 says it guides decisions on sealing the entry tear.^[1] In it, subscript P marks the proximal involved aorta and subscript D the distal zone.^[1]

• SVS/STS 2020 (as described by ACC/AHA 2022): type A (A with subscript D) for any dissection with an entry tear in zone 0; type B (B with subscripts P and D) for any dissection with an entry tear in zone 1 or beyond; and indeterminate (I with subscript D) when a dissection begins in zone 0 but the entry tear has not been identified.^[2]
• Non-A non-B dissection (ESC 2024): dissections limited to the aortic arch, or retrograde dissections from the descending aorta that extend into the arch and stop before the ascending aorta.^[1]
• ACC/AHA 2022 attributes the non-A-non-B category to a 2019 expert consensus document from the European Association for Cardio-Thoracic Surgery and the European Society for Vascular Surgery, for patients whose proximal dissection flap begins in the aortic arch.^[2]
• TEM (Type Entry Malperfusion): a recently proposed European update of the Stanford classification combining the type of dissection, its entry site and the presence of malperfusion, giving greater prognostic insight; ESC 2024 notes it is recommended by the European Association for Cardio-Thoracic Surgery.^[1]
• TEM malperfusion grades (ESC 2024 Figure 29): M0, no malperfusion; M1, coronary; M2, supra-aortic; M3, spinal, visceral, iliac.^[1]

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Epidemiology and risk factors

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Acute aortic dissection occurs mostly in males (about 65%) and in the seventh decade of life (about 63 years) (ESC 2024).^[1] ACC/AHA 2022 says men are more commonly affected and most dissections occur between 50 and 70 years, although patients with Marfan syndrome, bicuspid aortic valve (BAV), Loeys-Dietz syndrome and vascular Ehlers-Danlos syndrome present at younger ages.^[2][1]

Multiple risk factors often coexist, directly linked to factors such as wall stress (systemic hypertension being the most common) and/or aortic media abnormalities, including syndromic and non-syndromic genetic diseases (ESC 2024).^[1] HTAD, BAV, prior aortic surgery and larger aortic dimensions are more frequent among patients younger than 40 years.^[1] Pregnancy increases the risk of AAS, more often in the last trimester (50%) or post-partum (33%).^[1]

Including deaths before admission, 30-day mortality for acute aortic dissection ranges from 23% to 55.8% in Western Europe (ESC 2024).^[1] Iatrogenic dissection is very rare during cardiac catheterisation (around 0.01%–0.02%) and occurs in 0.06%–0.23% of cardiac surgery, with favourable in-hospital and long-term prognosis.^[1] Acute aortic dissection incidence peaks in the morning (between 8 am and 9 am) and in winter (January in the Northern Hemisphere) (ESC 2024).^[1]

ESC 2024 says a specific female phenotype appears to be evident in acute type A dissection: at admission, women are usually older, with lower body mass index, body surface area and creatinine.^[1] Women with acute type A dissection less often present with active smoking, BAV or previous cardiac surgery, but diabetes is more common in women than in men.^[1] In acute type A dissection, in-hospital surgical mortality does not differ between sexes, although 10-year survival appears higher in men (ESC 2024).^[1]

Pathophysiology

An intimal tear lets blood into the aortic media, splitting the intima in two longitudinally; the dissection flap then divides the true lumen from a newly formed false lumen (ACC/AHA 2022).^[2] The flap can propagate antegrade or retrograde and lead to a number of life-threatening complications, including acute aortic regurgitation (AR), myocardial ischaemia, cardiac tamponade, acute stroke or malperfusion syndromes.^[2]

ACC/AHA 2022 says blood surging in the false lumen may rupture back through the intima into the true lumen, creating a re-entry tear.^[2] ACC/AHA 2022 adds that if the false-lumen blood instead tears through the outer media and adventitia, aortic rupture results.^[2]

Malperfusion: how branches lose flow

Malperfusion syndrome is end-organ ischaemia related to inadequate perfusion of the aortic branch vessels (ACC/AHA 2022).^[2] Initially the true lumen collapses, because transmural pressure across the flap is lost and the medial smooth muscle recoils.^[2] At the same time the false lumen expands, depending on reduced elastic recoil, the depth of the dissection plane within the media and the percentage of the wall circumference involved.^[2] Any aortic branch is at risk as the false lumen expands and compresses the true lumen, and several beds can be affected at once as the dissection propagates.^[2]

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In its section on malperfusion in type A dissection, ESC 2024 says malperfusion typically combines dynamic and static obstructions, necessitating surgical and hybrid interventions for affected patients.^[1] In the same type A section, ESC 2024 reports that around 30% of patients develop malperfusion syndrome from elevated false-lumen pressure.^[1] ESC 2024 says the elevated false-lumen pressure in type A dissection comes from substantial proximal inflow and insufficient distal outflow, leading to visceral organ and limb ischaemia.^[1]

ESC 2024 describes the cornerstone of AAS care as initial reduction of the pulse pressure.^[1] ESC 2024 says the aim is to decrease aortic wall stress and so avoid further extension of the dissection with possible rupture or malperfusion.^[1]

^[2]

IMH and PAU

IMH involves vasa vasorum haemorrhage within the aortic media, with or without intimal disruption, and makes up 5%–25% of AAS (ESC 2024).^[1] ACC/AHA 2022 says fewer than 10% of IMH cases resolve spontaneously, whereas 16% to 47% progress to aortic dissection if the intimal layer ruptures and creates an entry tear.^[2]

A PAU begins as ulceration of an atherosclerotic plaque; the focal intimal disruption lets blood penetrate into the media, often with an IMH of variable size (ACC/AHA 2022).^[2]

Clinical presentation

The textbook word is tearing, but ACC/AHA 2022 says patients more commonly describe the pain another way.^[2] ACC/AHA 2022: patients more commonly report abrupt onset of severe sharp or stabbing pain in the chest or back (and sometimes abdomen), maximal at the start, that sometimes radiates.^[2] ESC 2024: acute type A dissection typically presents with sudden, severe chest/back pain, often described as sharp, alongside a history of arterial hypertension; around 6.4% of patients do not experience pain.^[1]

In acute type A dissection, ESC 2024 says hypotension and shock are frequent.^[1] Features specific to acute type A dissection include pericardial effusion, aortic regurgitation and coronary artery involvement leading to acute coronary syndrome (ACS), particularly of the right coronary artery.^[1] Stroke may occur when supra-aortic branches are involved, and further complications include paraplegia from spinal ischaemia, acute kidney injury, intestinal ischaemia and limb ischaemia.^[1] Isolated abdominal aortic dissection occurs in about 1.3% of acute type B cases, when the flap originates at or below the renal arteries.^[1]

Signs and symptoms of AAS and their causes (ACC/AHA 2022 Table 22, selected rows)

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Differential diagnosis

Diagnosing AAS can be challenging because the presenting symptoms overlap with other, more common emergency department complaints (ACC/AHA 2022).^[2]

Differential diagnosis and how the sources separate it

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Clinical and bedside assessment

ESC 2024 calls a complete clinical evaluation mandatory.^[1] The ESC 2024 clinical evaluation consists of a central neurological evaluation, heart and lung auscultation (aortic diastolic murmur, pericardial rub, etc.) and abdominal palpation (tenderness, etc.).^[1] The evaluation also assesses peripheral pulses and mobility and sensibility in the upper and lower limbs, and ESC 2024 says SBP differences (pulse deficit) should be sought.^[1]

ACC/AHA 2022 adds that BP should be measured in both arms and both lower extremities to exclude a BP differential resulting from an AAS.^[2] A careful history of the presenting symptoms is essential, as is a detailed family history of thoracic aortic aneurysms, genetic aortopathies, aortic dissection or unexplained sudden death.^[2] Listen for an aortic stenosis murmur, which may indicate an underlying BAV, and for AR, which commonly accompanies type A dissection.^[2]

The aortic dissection detection-risk score (ADD-RS)

Both guidelines use the same three categories, scoring 1 point for each category with at least one feature present, but they word the items and the risk bands differently.^[1][2]

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ACC/AHA 2022 adds that risk scores such as the ADD-RS or the aorta simplified score (AORTAs) can aid the diagnostic evaluation but have not been uniformly adopted.^[2]

Investigations

Early diagnosis is still a major pitfall in managing aortic dissection (ESC 2024).^[1] ESC 2024 therefore proposes a multiparametric algorithm that combines the ADD-RS with D-dimer, and says this algorithm has been validated with an excellent capacity to rule out AAS.^[1]

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ESC 2024: laboratory tests should be obtained, but awaiting results should not delay imaging if there is a high probability of aortic dissection; when D-dimer is below 500 ng/mL, dissection is unlikely.^[1] ACC/AHA 2022: no biomarker is diagnostic, but in patients with a low previous probability of AAS a non-elevated D-dimer (below 500 ng/mL) makes the diagnosis unlikely.^[2] ACC/AHA 2022 adds that integrating a low aortic dissection risk score and a low D-dimer may be a useful strategy to exclude the diagnosis of AAS.^[2]

ESC 2024 Recommendation Table 44: diagnostic work-up of acute aortic syndromes (all rows)

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• ACC/AHA 2022: in patients with a suspected AAS, computed tomography (CT) is recommended for initial diagnostic imaging, given its wide availability, accuracy and speed and the extent of anatomic detail it provides (COR 1, LOE C-LD).^[2]
• ACC/AHA 2022: in patients with a suspected AAS, transoesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) are reasonable alternatives for initial diagnostic imaging (COR 2a, LOE C-LD).^[2]

What each test adds

• CCT: ESC 2024 calls ECG-gated CCT from neck to pelvis the preferred technique when dissection is suspected, with 100% sensitivity and 98% specificity, to be performed as soon as possible to confirm the diagnosis, localise the entry tear and show extension (type A vs. type B) and malperfusion.^[1]
• ACC/AHA 2022: CT shows the full extent of the dissection and, in some cases, the entry tear, and can detect the presence and mechanism of branch vessel involvement, vessel patency, signs of malperfusion, pericardial effusion and haemopericardium, periaortic or mediastinal haematoma, and pleural effusion; ECG-synchronised CT should be considered when mediastinal structures such as the proximal aorta and coronary ostia need to be depicted accurately.^[2]
• Focused TTE: recommended in the emergency department if available, to assess pericardial effusion, wall motion abnormalities, aortic regurgitation and aortic diameters; sometimes a flap is seen, especially with contrast (ESC 2024).^[1]
• TOE/TEE: if CCT is not available or the patient is haemodynamically unstable, TOE can confirm the diagnosis, and it is especially useful pre-, intra- and post-operatively (ESC 2024). ACC/AHA 2022 prefers TEE to TTE because of its higher sensitivity and better anatomic resolution.^[1][2]
• CMR/MRI: CMR could be a valuable alternative to CCT, but it is less available, requires a longer examination time and relies on patient collaboration, so it is less frequently used acutely (ESC 2024). ACC/AHA 2022 calls MRI most commonly the third-choice modality, although it may be the study of choice in the acute setting for a stable patient with a contraindication to iodinated contrast.^[1][2]
• Chest radiography and ECG: recommended in chest pain to exclude other aetiologies, but their absence of findings should not delay further investigation (ESC 2024).^[1]

ACC/AHA 2022 says a plain chest X-ray is neither sufficiently sensitive nor specific to diagnose AAS.^[2] ACC/AHA 2022 adds that certain chest X-ray findings may raise suspicion of dissection or suggest an alternative diagnosis, in particular when earlier films show them to be new.^[2]

• Signs of aortic dissection on chest X-ray (ACC/AHA 2022 Table 23): mediastinal widening; disruption of the normally distinct contour of the aortic knob; the calcium sign, a separation of the intimal calcification from the aortic wall of more than 5 mm; a double density within the aorta; tracheal deviation to the right; and deviation of the nasogastric tube to the right.^[2]

Management — resuscitation: anti-impulse therapy

ACC/AHA 2022: immediate medical therapy is indicated in all patients with AAS while urgent surgery (type A), endovascular intervention (type B) or both are considered.^[2] ACC/AHA 2022 says this immediate medical therapy includes aggressive heart rate and BP management plus pain control.^[2] ESC 2024 adds that AAS care should be centralised in experienced centres and managed by aorta teams.^[1]

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The heart-rate targets differ: 60 b.p.m. or less in ESC 2024 against 60 to 80 bpm in ACC/AHA 2022.^[1][2] Anti-impulse treatment in both guidelines aims to decrease aortic wall stress; ESC 2024 adds that this is to avoid further extension of the dissection with possible rupture or malperfusion.^[1][2]

ESC 2024 Recommendation Table 45: medical treatment in acute aortic syndromes (all rows)

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• ACC/AHA 2022: in patients presenting to hospital with AAS, prompt anti-impulse therapy with invasive monitoring of BP with an arterial line in an intensive care unit (ICU) setting is recommended as initial treatment to decrease aortic wall stress (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: initial management should include intravenous beta-blockers, except in patients with contraindications (COR 1, LOE B-NR); in those with contraindications or intolerance to beta-blockers, initial management with an intravenous non-dihydropyridine calcium channel blocker is reasonable for heart rate control (COR 2a, LOE B-NR).^[2]
• ACC/AHA 2022: initial management should include intravenous vasodilators if BP is not well controlled after intravenous beta-blocker therapy has been started (COR 1, LOE C-LD).^[2]
• ACC/AHA 2022: patients with AAS should be treated with pain control, as needed, to help with haemodynamic management (COR 1, LOE C-EO).^[2]

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Choosing and sequencing the drugs

Rate control comes before vasodilatation.^[1][2] ESC 2024 says intravenous beta blockade is generally accepted as the best option, with labetalol as first choice because of its alpha- and beta-blocking properties.^[1] Esmolol, an ultra-short-acting beta-blocker that can be titrated quickly and easily, is particularly useful in the acute setting.^[1] If beta-blockers are contraindicated, intravenous non-dihydropyridine calcium channel blockers (CCBs) could be used for heart rate control.^[1]

ESC 2024: if the BP target is not reached after beta-blockers are started, intravenous vasodilators such as nitrates or dihydropyridine CCBs (e.g. nicardipine) can be given.^[1] ESC 2024 says these vasodilators can be given concomitantly with rate-controlling agents, which are started first to avoid reflex tachycardia.^[1] ACC/AHA 2022 says vasodilators are useful adjuncts to intravenous beta-blockers but should be avoided as initial treatment, before beta-blockers or CCBs, because of the potential for compensatory tachycardia.^[2]

ACC/AHA 2022 names the drugs usually combined: intravenous beta-blockers (e.g. esmolol, metoprolol and labetalol) with vasodilators (e.g. nicardipine, clevidipine and sodium nitroprusside).^[2] ACC/AHA 2022 notes that no randomised studies have compared medical treatments in AAS; the standard rests on extensive clinical experience.^[2] ACC/AHA 2022 says caution should be used in patients with contraindications to beta-blockers (e.g. acute AR, heart block or bradycardia).^[2] In patients intolerant to beta-blockers, ACC/AHA 2022 says intravenous non-dihydropyridine calcium channel blockers (i.e. verapamil or diltiazem) are typically used for initial treatment.^[2] Drug doses: per local formulary and specialist guidance.

Pain related to AAS can trigger a rise in heart rate and BP, so treating it can help control both, and intravenous opiates are particularly efficacious (ACC/AHA 2022).^[2] ACC/AHA 2022 adds that intravenous non-steroidal anti-inflammatory drugs such as ketorolac may not be suitable because of the risk of inducing hypertension as well as adverse renal effects.^[2] ESC 2024 says intravenous morphine can be cautiously titrated for pain relief.^[1]

ESC 2024 text calls early placement of an arterial line mandatory and intensive care admission advisable, with ECG and urine output monitoring.^[1] ESC 2024 says antihypertensive treatment can be gradually switched to oral therapy once BP and heart-rate targets are reached and the patient has normal gastrointestinal transit.^[1]

Management — definitive: acute type A dissection

ESC 2024 describes a mortality of about 50%, at 1%–2% per hour, within the first 48 h if acute type A dissection is managed medically only.^[1] ACC/AHA 2022 gives the mortality of unoperated acute type A dissection as 1%/h and says medical management alone carries 2 to 3 times the mortality of surgery.^[2]

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ESC 2024 Recommendation Table 46: intervention in type A acute aortic dissection (all rows)

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ESC 2024 Recommendation Table 47: aortic repair strategies in type A acute aortic dissection (all rows)

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• ACC/AHA 2022: in patients presenting with suspected or confirmed acute type A dissection, emergency surgical consultation and evaluation and immediate surgical intervention is recommended because of the high risk of life-threatening complications (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in patients presenting with acute type A dissection who are stable enough for transfer, transfer from a low- to a high-volume aortic centre is reasonable to improve survival (COR 2a, LOE B-NR); the supporting text defines a high-volume hospital as one performing 7 or more aortic root, ascending aorta or transverse arch dissection repairs per year.^[2]
• ACC/AHA 2022: with a partially dissected aortic root but no significant aortic valve leaflet pathology, aortic valve resuspension is recommended over valve replacement (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: with extensive destruction of the aortic root, a root aneurysm or a known genetic aortic disorder, aortic root replacement with a mechanical or biological valved conduit is recommended (COR 1, LOE B-NR); in selected stable patients, valve-sparing root repair may be reasonable when performed by experienced surgeons in a Multidisciplinary Aortic Team (COR 2b, LOE C-LD).^[2]
• ACC/AHA 2022: in patients undergoing aortic repair, an open distal anastomosis is recommended to improve survival and increase false-lumen thrombosis rates (COR 1, LOE B-NR); without an intimal tear in the arch or a significant arch aneurysm, hemiarch repair is recommended over more extensive arch replacement (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: with a dissection flap extending through the arch into the descending thoracic aorta, an extended repair with antegrade stenting of the proximal descending thoracic aorta may be considered to treat malperfusion and reduce late distal aortic complications (COR 2b, LOE C-LD).^[2]
• ACC/AHA 2022: in patients undergoing surgical repair, axillary cannulation, when feasible, is reasonable over femoral cannulation to reduce the risk of stroke or retrograde malperfusion (COR 2a, LOE B-NR); in those who require circulatory arrest, cerebral perfusion is reasonable to improve neurologic outcomes (COR 2a, LOE B-NR).^[2]
• ACC/AHA 2022: in patients undergoing surgical repair, direct aortic or innominate artery cannulation with imaging guidance is reasonable as an alternative to femoral or axillary cannulation (COR 2a, LOE B-NR).^[2]

Who should go to theatre?

ESC 2024 says surgery surpasses conservative therapy in long-term follow-up, even for challenging cases, so all patients with acute type A dissection should receive surgical treatment.^[1] Cardiogenic shock from pericardial tamponade, malperfusion of the coronary arteries, mesenteric circulation, lower extremities, kidneys or brain, and/or coma are major predictors of post-operative mortality.^[1]

Age alone should not exclude surgery.^[1] Among octogenarians, in-hospital mortality was lower after surgery than with conservative treatment (37.9% vs. 55.2%), but the difference was not significant owing to small sample size (ESC 2024).^[1] Some report excellent surgical and quality-of-life outcomes in elderly patients and others more post-operative neurological complications, and ESC 2024 concludes that age per se should not be considered an exclusion criterion.^[1] ACC/AHA 2022 says that although age is a risk factor, elderly patients still benefit from surgery, with superior immediate and midterm outcomes compared with medical therapy.^[2] ACC/AHA 2022 adds that clinical judgement may favour medical management in patients with significant contraindications such as frailty.^[2]

ESC 2024 says the GERAADA (German Registry of Acute Aortic Dissection Type A) score should be considered in patients undergoing surgery to determine 30-day mortality.^[1] For potential cardiac arrest from pericardial tamponade, ESC 2024 advises considering an emergency pericardial puncture as a temporary life-saving measure before transfer to the operating room.^[1]

What the operation tries to achieve

ACC/AHA 2022 lists the goals of open or endovascular repair of acute dissection.^[2] The ACC/AHA 2022 goals are to prevent or treat rupture, prevent retrograde extension into the aortic root, prevent antegrade propagation into undissected segments, and relieve malperfusion syndromes.^[2] To reduce the risk of late aortic complications in acute type A repair, ACC/AHA 2022 says surgical resection should include the tear site, any aneurysmal aorta and the proximal-most extent of the dissection.^[2] ACC/AHA 2022 adds that a non-resected primary tear is a risk factor for reoperation.^[2]

In most cases of AR with acute type A dissection, the aortic valve is essentially normal and can be preserved; valve replacement can be performed for pre-existing structural valve disease (ESC 2024).^[1] ESC 2024 says whether to replace the root depends on tears in the sinuses, extensive dissection of the sinuses or coronary ostia, or significant root dilatation, and that the risk of late dilatation of spared sinuses should be considered.^[1] ACC/AHA 2022 adds that an aortic root diameter above 4.5 cm has been shown to be a risk factor for late reintervention.^[2]

The distal extent of repair is debated (ESC 2024).^[1] ESC 2024 says ascending or hemi-arch replacement alone is technically easier and closes the entry site but leaves much of the diseased aorta untreated.^[1] With visceral or renal malperfusion the primary entry tear is often in the descending aorta, and ESC 2024 suggests considering extended therapies such as frozen elephant trunk (FET) repair, which offers a complete repair with a low chance of late re-intervention despite increased technical complexity.^[1] ACC/AHA 2022 cites GERAADA data showing a trend towards lower mortality with hemiarch than total arch replacement (18.7% versus 25.7%; P=0.07).^[2] In patients requiring total arch replacement, ACC/AHA 2022 says a frozen elephant trunk has higher adverse events in acute type A dissection than in elective repairs.^[2] ACC/AHA 2022 adds that the frozen elephant trunk stent should be shorter than 15 cm and, to avoid spinal cord injury, coverage should not extend to T8.^[2]

Endovascular therapy alone for type A dissection has been attempted in highly selected cases, and a single endovascular valve-carrying conduit has been suggested but not yet validated (ESC 2024).^[1]

Malperfusion in acute dissection

Both guidelines discuss malperfusion management in their acute type A sections.^[1][2] ESC 2024 does so under "Malperfusion in type A aortic dissection"; ACC/AHA 2022 under 7.4.1.2, within 7.4.1 Acute Type A Aortic Dissection.^[1][2] ACC/AHA 2022: imaging evidence of malperfusion is present in as many as 25% of patients with acute type A dissection, but it should be distinguished from clinical end-organ ischaemia (malperfusion syndrome).^[2] In that acute type A section, ACC/AHA 2022 gives malperfusion syndrome a mortality of 30.5%, against 6.2% without it.^[2] In that type A section, ACC/AHA 2022 says mortality correlates with the number of branch vessels involved and of malperfused organs, and early reperfusion predicts survival.^[2]

Clinical evidence of malperfusion (malperfusion syndrome) (ACC/AHA 2022 Table 26, all rows)

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ESC 2024 Recommendation Table 48: malperfusion in the setting of acute aortic dissection (all rows; every row applies to acute type A dissection)

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• ACC/AHA 2022: in patients with acute type A dissection presenting with renal, mesenteric or lower extremity malperfusion, immediate operative repair of the ascending aorta is recommended (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in patients with acute type A dissection presenting with clinically significant mesenteric (coeliac, superior mesenteric artery) malperfusion, either immediate operative repair of the ascending aorta or immediate mesenteric revascularisation via endovascular or open surgery by those with this expertise before ascending aortic repair is reasonable (COR 2a, LOE C-LD).^[2]
• ACC/AHA 2022: in patients presenting with non-haemorrhagic stroke complicating acute type A dissection, surgical intervention is reasonable over medical therapy to reduce mortality and improve neurologic outcomes (COR 2a, LOE B-NR).^[2]

In acute type A dissection, mesenteric malperfusion divides opinion on the order of treatment.^[1][2] For mesenteric malperfusion in acute type A dissection, ESC 2024 gives a mortality of 65%–95% and notes that some centres prefer early direct reperfusion before aortic surgery while others favour conventional central aortic repair.^[1] ACC/AHA 2022 gives mesenteric malperfusion in acute type A dissection a mortality of 63.2%.^[2] ACC/AHA 2022 notes that, in IRAD, patients with acute type A dissection and mesenteric ischaemia treated without intervention had an in-hospital mortality of 95%, and says data are limited to define the best strategy.^[2] For mesenteric malperfusion in acute type A dissection, ESC 2024 says the IRAD registry shows the superiority of a surgical and hybrid approach over medical or endovascular therapy alone.^[1]

In acute type A dissection, ESC 2024 calls cerebral malperfusion equally grave.^[1] For cerebral malperfusion, ESC 2024 says evidence supports surgery, reducing mortality to 25%–27% compared with 76% with medical management alone; ACC/AHA 2022 gives the same figures for acute type A dissection with acute stroke.^[1][2]

Management — definitive: acute type B dissection

In type B dissection the first question is whether it is complicated.^[1] ESC 2024: acute type B dissection presents without complications in around 50% of cases.^[1] Complicated acute type B includes aortic rupture, malperfusion-related issues, rapid aortic expansion, paraplegia/paraparesis, aortic haematoma, refractory pain, and hypertension despite optimal therapy, and it carries an approximately 50% mortality risk with conservative treatment.^[1]

^{[1] [2]}

Open surgery used to be the sole option for complicated acute type B dissection but carried a mortality of 25%–50% (ESC 2024).^[1] Medical management, now considered the standard for uncomplicated cases, significantly reduces mortality, with goals that include lowering SBP and heart rate with beta-blockers.^[1] Endovascular therapy for complicated acute type B is now first-line provided there is favourable anatomy, because of positive short- and long-term outcomes; open surgery is reserved for unsuitable cases, and fenestration could be considered as an ultima ratio.^[1]

Adherence is the main limitation of chronic medical treatment, at a rate below 50%, so ESC 2024 calls surveillance and disease awareness imperative.^[1] ACC/AHA 2022 adds that, in an emergency, TEVAR has significantly lower morbidity and in-hospital mortality than open repair, with the greatest advantage among older patients.^[2] For rupture, rapid coverage of the affected region of the descending aorta may be lifesaving and does not preclude later endovascular or open repair, an important consideration in genetically triggered aortic disease (e.g. Marfan or Loeys-Dietz syndrome).^[2]

ESC 2024 Recommendation Table 49: patients presenting with acute type B aortic dissection (all rows)

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• ACC/AHA 2022: in all patients with uncomplicated acute type B dissection, medical therapy is recommended as the initial management strategy (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in patients with acute type B dissection and rupture or other complications (Table 27), intervention is recommended (COR 1, LOE C-LD). With rupture and suitable anatomy, endovascular stent grafting rather than open surgical repair is recommended (COR 1, LOE C-EO); with other complications and suitable anatomy, endovascular rather than open repair is reasonable (COR 2a, LOE C-LD).^[2]
• ACC/AHA 2022: in patients with uncomplicated acute type B dissection who have high-risk anatomic features (Table 28), endovascular management may be considered (COR 2b, LOE B-R).^[2]

Predicting a complicated course

ESC 2024 notes that aortic characteristics change over time and that endovascular treatment in the chronic phase offers limited potential for aortic remodelling.^[1] ESC 2024 says identifying specific characteristics at the time of acute type B diagnosis that predict a complicated course has been attempted.^[1] Independent predictors of type B dissection outcomes listed by ESC 2024 include the following.^[1]

• A primary entry tear over 10 mm located at the inner aortic curvature^[1]
• Initial aortic diameter over 40 mm and initial false-lumen diameter over 20 mm^[1]
• The number and size of fenestrations between the true and false lumen^[1]
• Stent graft-induced new entry tear, and partial false-lumen thrombosis^[1]

ESC 2024 says these parameters are summarised in DISSECT, a new categorisation system that guides and supports therapeutic decisions.^[1] DISSECT stands for Duration from onset of symptoms, Intimal tear location, Size of the aorta based on maximum trans-aortic diameter, Segmental Extent, Clinical complications related to the dissection, and Thrombosis of the false lumen.^[1]

Uncomplicated but high risk

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Refractory hypertension and pain: complicated versus high-risk uncomplicated

Both bodies list uncontrolled or refractory hypertension and intractable or refractory pain among the features of complicated acute type B (ACC/AHA 2022 Table 27; ESC 2024 Figure 33).^[2][1] In ESC 2024 Figure 33 the pain feature is refractory pain for more than 12 h, and refractory hypertension is ongoing hypertension despite more than three classes of antihypertensive drugs.^[1] ACC/AHA 2022 Table 28 also lists, among the high-risk clinical findings in uncomplicated disease, refractory hypertension despite more than 3 different classes of antihypertensive medication at maximal recommended or tolerated doses and refractory pain persisting more than 12 h despite maximal recommended or tolerated doses.^[2]

Interventional treatment algorithm in acute aortic dissection (ESC 2024 Figure 33)

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Favourable TEVAR anatomy means adequate proximal and distal landing zones for the prosthesis and adequate iliac/femoral vessels for vascular access (ESC 2024).^[1]

^[1]

The evidence and the debate

Two trials are named by ESC 2024: ADSORB (Acute Dissection Stentgraft OR Best Medical Treatment) and INSTEAD-XL (Investigation of Stent Grafts in Aortic Dissection with extended length of follow-up).^[1] ESC 2024 reports that these trials found early intervention for uncomplicated acute and subacute type B dissection beneficial compared with medical management, and that whether to treat uncomplicated acute type B to improve life expectancy is debated.^[1] Intervention is considered early, within 90 days of symptom onset, and may be safer in the subacute phase (more than 14 days after onset), but data are scarce.^[1] A recent meta-analysis found TEVAR superior to best medical therapy in uncomplicated acute type B: early outcomes were similar, but TEVAR was associated with fewer long-term events and better aortic remodelling.^[1] ESC 2024 therefore says pre-emptive TEVAR should be considered in stable type B dissection with suitable anatomy and high-risk features, to improve late outcome.^[1]

ESC 2024 notes that the Society of Thoracic Surgeons/American Association for Thoracic Surgery (STS/AATS) 2022 guidelines say prophylactic TEVAR may be considered in patients with suitable anatomy and high-risk features to reduce late aortic-related adverse events.^[1] ESC 2024 adds that the matter is not entirely settled and that the Improving outcomes in vascular disease—aortic dissection (IMPROVE-AD) trial is underway.^[1] IMPROVE-AD aims to evaluate clinical outcomes in subacute (48 h to 6 weeks) uncomplicated type B dissection, comparing upfront TEVAR plus medical therapy against medical therapy with surveillance for deterioration (ESC 2024).^[1] ACC/AHA 2022 says the ADSORB and INSTEAD-XL findings appear promising, but larger trials with longer-term data are still needed, and that the optimal timing of TEVAR remains unknown.^[2]

Chronic type B dissection

ESC 2024 considers type B dissection chronic 3 months after symptom onset, including residual type B dissection after type A repair; aortic complications, especially aneurysmal degeneration, occur in up to 50% of these patients.^[1] In chronic type B dissection, ESC 2024 says indications for treatment include the onset of new aortic symptoms such as rapid expansion, malperfusion or rupture.^[1] In asymptomatic patients with chronic type B dissection, ESC 2024 says aneurysmal dilatation is the most important risk factor for rupture, with rupture risk reaching 20% when the diameter exceeds 55 mm.^[1] ESC 2024 reports rupture risks of 15.3% and 18.8% between 50–55 mm and 54–56 mm, suggesting 50–55 mm as a threshold for elective surgery, but says smaller diameters should be considered in patients with HTAD.^[1]

Open surgery remains first-line in low-risk patients or those with HTAD, despite the lack of data comparing it with TEVAR (ESC 2024).^[1] ESC 2024 calls TEVAR the preferred treatment for eligible chronic type B patients, with low early mortality (below 5%) and stroke and spinal cord ischaemia rates below 3%, and says it also suits high-risk patients who are ineligible for open repair.^[1] The primary goal of TEVAR in chronic type B dissection is to close the entry tear, induce false-lumen thrombosis and promote aortic remodelling, to mitigate growth and rupture risk (ESC 2024).^[1]

ESC 2024 Recommendation Table 50: patients presenting with chronic type B aortic dissection (all rows)

^[1]

Non-A non-B dissection

Non-A non-B patients tend to be younger (median age 59 years) and have lower mortality than patients with acute type A dissection (ESC 2024).^[1] Conservative management leads to high mortality (malperfusion, aortic rupture), so surgery or endovascular therapy is favoured within 14 days of symptom onset.^[1] For complicated non-A non-B dissection with an arch tear, ESC 2024 advises considering FET repair, with stent-graft coverage of the primary tear as an alternative if feasible.^[1]

Specific subtypes: intramural haematoma and penetrating ulcer

Intramural haematoma (IMH)

IMH makes up 5%–25% of AAS (ESC 2024).^[1] Most IMH cases (60%–70%) involve the descending thoracic aorta, with the ascending aorta in about 30% and the arch in about 10%.^[1] IMH usually occurs at an older age than dissection with similar risk factors and symptoms, but AR, malperfusion syndrome and pulse deficits are less frequent in type A IMH than in type A dissection.^[1]

On imaging, ESC 2024 names CCT and CMR (followed by TOE) as the leading techniques, with unenhanced then contrast-enhanced CCT the most used tool acutely.^[1] ESC 2024 says the IMH hallmark is crescentic or circular aortic wall thickening without an intimal flap or wall enhancement after contrast, and that TTE has low sensitivity (below 40% for an IMH cut-off of 5 mm).^[1] ACC/AHA 2022 says IMH is diagnosed by CT angiography, MRI or echocardiography by the presence of circular or crescent-shaped thickening of the aortic wall of more than 5 mm in the absence of detectable blood flow.^[2]

IMH may evolve into dissection (12%), saccular (8%) or fusiform aneurysm (22%) and/or intimal disruption (54%), and partial or total regression is reported in 34% (ESC 2024).^[1] In-hospital mortality is 26.6% for type A IMH (surgical 24.1%, medical 40.0%) and 4.4% for type B IMH, worsening once surgery is indicated (surgical 20.0% vs. medical 3.8%).^[1] Reports from South Korea and Japan show a higher IMH incidence than Western series (28.9% vs. 5.7% of overall dissection reported by IRAD) (ESC 2024).^[1] In Eastern regions most type A IMH patients (80.8%) were treated medically, with significantly improved outcomes (in-hospital mortality 6.6%: 5.9% medical, 9.4% surgical).^[1] ESC 2024 adds that these results may be partially explained by the detection of early-stage IMH (mild, uncomplicated cases) at primary centres.^[1] Separately, ACC/AHA 2022 notes that experience with successful medical management of type A IMH comes mostly from Japan, Korea and China, all reporting outcomes better than in North America and Europe.^[2] ACC/AHA 2022 says the differences might be related to genetic or environmental factors affecting IMH natural history, so the Asian results may not be generalisable to other ethnic or geographic populations.^[2]

^{[1] [2]}

ESC 2024 Recommendation Table 51: management of intramural haematoma (all rows)

^[1]

In Table 51, uncomplicated and complicated IMH refer to the absence or presence of recurrent pain, expansion of the IMH, periaortic haematoma and intimal disruption, and the high-risk features are those of Table 16 (ESC 2024).^[1] Intimal disruption is described in 54% of type B IMH (ESC 2024).^[1] About 28% of these type B IMH intimal disruptions are tiny (3 mm or less) and not related to aortic adverse events, but 14% evolve into focal intimal disruptions (over 3 mm) with prognostic implications.^[1] All patients with intimal disruption in type B IMH therefore need close imaging follow-up.^[1]

• ACC/AHA 2022: in complicated (Table 29) acute type A or type B IMH, urgent repair is recommended (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in uncomplicated acute type A IMH, prompt open surgical repair is recommended (COR 1, LOE B-NR); in selected patients with uncomplicated acute type A IMH who are at increased operative risk and do not have high-risk imaging features (Table 30), an initial or expectant approach of medical management may be considered (COR 2b, LOE C-LD).^[2]
• ACC/AHA 2022: in uncomplicated acute type B IMH, medical therapy as the initial management strategy is recommended (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in type B IMH needing repair of the distal aortic arch or descending thoracic aorta (zones 2–5), endovascular repair is reasonable with favourable anatomy when performed by surgeons with endovascular expertise (COR 2a, LOE C-LD), and open surgical repair is reasonable with unfavourable anatomy for endovascular repair (COR 2a, LOE C-LD).^[2]
• ACC/AHA 2022: in uncomplicated type B IMH with high-risk imaging features (Table 30), intervention may be reasonable (COR 2b, LOE C-LD).^[2]
• These are all six ACC/AHA 2022 Section 7.5 IMH rows.^[2]

Penetrating atherosclerotic ulcer (PAU)

PAU accounts for 2%–7% of AAS and is frequently associated with IMH and diffuse atherosclerosis (ESC 2024).^[1] Most patients are older males, smokers, aged over 65, with multiple comorbidities such as systemic hypertension, coronary artery disease, chronic obstructive pulmonary disease, renal insufficiency and concurrent abdominal aneurysm.^[1] The ascending aorta is rarely affected, but when it is, especially with IMH, the rupture risk is 33%–75% and progression to dissection carries a high mortality.^[1] Symptom onset may indicate PAU expansion (adventitial involvement), so urgent imaging (CCT or CMR) and appropriate intervention are needed to prevent rupture.^[1]

ESC 2024 Recommendation Table 52: management of penetrating atherosclerotic ulcer (all rows)

^[1]

• ACC/AHA 2022 (PAU with IMH, rupture or both): with rupture, urgent repair is recommended (COR 1, LOE B-NR); in PAU of the ascending aorta with associated IMH, urgent repair is recommended (COR 1, LOE B-NR); in PAU of the aortic arch or descending thoracic aorta with associated IMH, urgent repair is reasonable (COR 2a, LOE C-LD); in PAU of the abdominal aorta with associated IMH, urgent repair may be considered (COR 2b, LOE C-LD).^[2]
• ACC/AHA 2022 (isolated PAU): in symptomatic patients with persistent pain clinically correlated with the radiologic findings, repair is recommended (COR 1, LOE B-NR); in asymptomatic patients with high-risk imaging features (its Table 31), elective repair may be considered (COR 2b, LOE C-LD).^[2]
• ACC/AHA 2022 (open versus endovascular repair of PAU): for PAU of the ascending aorta or proximal arch (zones 0–1), open surgical repair is recommended (COR 1, LOE C-LD); for PAU of the distal arch (zones 2–3), descending thoracic or abdominal aorta, either open surgical or endovascular repair is reasonable, based on anatomy and medical comorbidities (COR 2a, LOE C-LD).^[2]

Complications and pitfalls

• Painless presentation: around 6.4% of patients with acute type A dissection do not experience pain (ESC 2024).^[1]
• Deadly complications in type A: cardiogenic shock from tamponade, malperfusion of the coronary, mesenteric, lower-limb, renal or cerebral circulation, and coma are major predictors of post-operative mortality (ESC 2024).^[1]
• In-hospital mortality of AAS reaches 60% and correlates with AAS type, location, comorbidities and treatment; risk rises with tamponade, coronary involvement or malperfusion (ESC 2024).^[1]
• After TEVAR: patients treated with TEVAR for AAS involving the descending aorta are more prone (27%–49%) to a second intervention than those having surgical repair, and an early 1-month scan is necessary to exclude asymptomatic TEVAR-induced retrograde type A dissection, 70% of which occur within 30 post-operative days (ESC 2024).^[1]
• Endoleak and a patent false lumen: after TEVAR for acute type B dissection, a patent false lumen can lead to aneurysm growth, with early endoleaks in up to 35% and late endoleaks in 13% of patients (ACC/AHA 2022).^[2]
• Poor adherence: adherence to chronic medical treatment of type B dissection is below 50% (ESC 2024).^[1]
• TEVAR sizing in AAS (ESC 2024, in its acute type B section): aortic diameter fluctuates with haemorrhagic shock and resuscitation, admission CCT may be imprecise, and real-time imaging, especially intravascular ultrasound (IVUS), enhances accuracy, particularly in hypovolaemic cases.^[1]

Prognosis and long-term follow-up

Surviving the acute event does not end the risk: ACC/AHA 2022 says survival after acute aortic dissection and IMH does not guarantee freedom from subsequent aortic events, because of residual aortic dissection and the risk of aneurysm formation.^[2] ACC/AHA 2022: 10-year survival after repair of acute type A dissection is approximately 60% to 65%, and reoperation risk is increased for the aortic valve, root and distal aorta, with a distal aortic reoperation risk of 10% to 16% at 10 years.^[2] Medically managed uncomplicated type B dissection has a favourable early prognosis, but delayed aortic expansion occurs in 20% to 50% of patients over 4 years, so regular surveillance imaging is essential.^[2]

ESC 2024 says surveillance modality and intervals vary with lesion location, type of treatment and underlying disease such as HTAD.^[1] ESC 2024 says that, after invasive treatment of AAS, time to re-intervention in patients developing complications is significantly shorter than after open surgery for aortic aneurysms.^[1] ESC 2024 attributes this partly to the faster average growth of the dissected aorta (about 1 mm per year).^[1] In its section on follow-up under medical treatment, ESC 2024 notes that around 70% of type B dissection patients survive the hyperacute phase.^[1] For type B dissection under medical treatment, ESC 2024 says chronic dilatation reaching 55 mm is the leading cause of intervention (about 40%).^[1] For type B dissection under medical treatment, the ESC 2024 text says imaging controls should be performed at least at 1, 6 and 12 months after discharge and yearly thereafter.^[1] In type B dissection under medical treatment, ESC 2024 says one additional earlier scan, e.g. within 3 months, may reveal important changes in the subacute phase, when the dissected aorta remains successfully amenable to early TEVAR.^[1] The formal schedules are the Recommendation Table 54 rows below.^[1]

ESC 2024 Recommendation Table 54: follow-up after treatment of acute aortic syndrome (all rows)

^[1]

In Table 54, complications and abnormalities include pseudo-aneurysm, graft infection, endoleak (any type), enlargement of the excluded aneurysm, and stent graft migration, separation or fracture (ESC 2024).^[1]

• ACC/AHA 2022: after acute aortic dissection and IMH treated with open or endovascular repair with residual aortic disease, surveillance CT (or MRI) is recommended after 1, 6 and 12 months and then, if stable, annually (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: after acute aortic dissection and IMH managed with medical therapy alone, surveillance CT (or MRI) is recommended after 1, 6 and 12 months and then, if stable, annually (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: after previous acute aortic dissection and IMH, whether treated medically or with intervention, with chronic residual thoracic aortic disease and an aneurysm with a total aortic diameter of 5.5 cm or more, elective thoracic aortic repair is recommended (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022 adds that TTE can help monitor aortic root anatomy and aortic valve function over time, alongside cross-sectional imaging of most of the aorta.^[2]

^[1]

Long-term medical therapy

• ACC/AHA 2022: in patients with AAS, long-term beta-blockers (unless contraindicated) are recommended to control heart rate and BP and reduce late aortic adverse events, with additional antihypertensive agents (particularly angiotensin receptor blockers [ARBs] and angiotensin-converting enzyme inhibitors [ACEIs]) added as necessary to control BP (COR 1, LOE B-NR).^[2]
• ESC 2024: antihypertensive therapy is recommended in all patients with chronic type B dissection (Class I, Level B).^[1]
• ESC 2024: clinical follow-up aims at strict BP control, limiting the burden of cardiovascular risk factors, and counselling on lifestyle and sport; there is evidence that statins may improve survival in AAS patients under medical treatment, whereas beta-blockers may improve survival in surgically treated patients.^[1]
• ACC/AHA 2022: calcium channel blockers showed some benefit in type B dissection, but mouse models of Marfan syndrome and case-control studies in Marfan syndrome and other inherited aortopathies in the Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC) registry showed deleterious effects of long-term use, so it may be best to avoid them in Marfan syndrome unless necessary to achieve BP control.^[2]

Special populations

Pregnancy

Pregnancy increases the risk of AAS, more often in the last trimester (50%) or post-partum (33%) (ESC 2024).^[1] In its section on pregnancy in patients with aortopathy, ACC/AHA 2022 says pregnancy is a risk factor for aortic dissection in women with aortopathy.^[2] In that aortopathy section, ACC/AHA 2022 says dissection may occur throughout pregnancy or several weeks post-partum, most in the third trimester or up to 12 weeks post-partum.^[2]

ESC 2024 says management of dissection in pregnancy requires a multidisciplinary team and specialised centres, with initial care following the general medical recommendations but using drugs with the lowest teratogenic impact.^[1] In type A dissection in pregnancy, ESC 2024 says caesarean delivery is performed before aortic repair if the fetus is viable; if not, surgery is done with the fetus in place.^[1] In uncomplicated type B dissection in pregnancy, ESC 2024 recommends strict control of mother and fetus with conservative medical management, and says successful TEVAR has been described in selected complicated cases.^[1]

Older patients and women

Age per se should not be considered an exclusion criterion for type A surgery (ESC 2024).^[1] Among octogenarians with acute type A dissection, in-hospital mortality was 37.9% after surgery against 55.2% with conservative treatment, a non-significant difference owing to small sample size (ESC 2024).^[1] Among medically treated women and men with acute type A dissection, in-hospital mortality was prohibitively high in both sexes (men 58.6% vs. women 53.8%).^[1]

Heritable thoracic aortic disease and family screening

ESC 2024 groups genetic diseases affecting the thoracic aorta under heritable thoracic aortic disease (HTAD): familial forms (thoracic aortic disease in 2 or more individuals in one family), confirmed genetic entities (familial or sporadic) and syndromes conferring a risk of thoracic aortic disease.^[1] All HTAD entities display cystic medial degeneration, which hinders precise diagnosis by pathology, and genetic testing should always be accompanied by appropriate counselling.^[1] ACC/AHA 2022 says up to 20% of individuals with a thoracic aortic aneurysm or dissection have a family history of thoracic aortic disease, with at least 1 affected first-degree relative.^[2]

ESC 2024 Recommendation Table 56: genetic testing rows (the aortic imaging screening rows of the same table are not reproduced here)

^[1]

• ESC 2024: it is recommended that patients with known or suspected syndromic or non-syndromic HTAD are evaluated in a centre with experience in the care of this patient group (Class I, Level C).^[1]
• ACC/AHA 2022: in patients with aortic root/ascending aortic aneurysms or aortic dissection, obtaining a multigenerational family history of thoracic aortic disease, unexplained sudden deaths, and peripheral and intracranial aneurysms is recommended (COR 1, LOE B-NR).^[2]
• ACC/AHA 2022: in patients with aortic root/ascending aortic aneurysms or aortic dissection and risk factors for HTAD (its Table 8), genetic testing to identify pathogenic/likely pathogenic variants is recommended (COR 1, LOE B-NR). Table 8 lists thoracic aortic disease with syndromic features of Marfan, Loeys-Dietz or vascular Ehlers-Danlos syndrome; thoracic aortic disease presenting before 60 years; a family history of thoracic aortic disease or peripheral/intracranial aneurysms in a first- or second-degree relative; and unexplained sudden death at a relatively young age in a first- or second-degree relative.^[2]
• ACC/AHA 2022: with aortic root/ascending aortic aneurysms or aortic dissection but no known family history of thoracic aortic disease and no pathogenic/likely pathogenic variant, screening aortic imaging of first-degree relatives is recommended (COR 1, LOE C-LD), using the imaging of its recommendation 4: TTE if the aortic root and ascending aorta are adequately visualised, otherwise CT or MRI.^[2]
• ACC/AHA 2022: in acute type A dissection, the diameter of the aortic root and ascending aorta should be recorded in the operative note and medical record to inform the management of affected relatives (COR 1, LOE C-EO).^[2]

Evidence, guidelines and regional differences

Landmark trials in uncomplicated type B dissection

ACC/AHA 2022 adds that there has been no large randomised trial comparing open with endovascular repair for complicated or uncomplicated type B dissection.^[2]

Where ESC 2024 and ACC/AHA 2022 differ

Differences between the two guidelines (recommendation rows unless the row label names a figure or table)

^{[1] [2]}

Exam pearls

References5ShowHide

1. [1]Mazzolai L, et al. 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases. Eur Heart J, 2024.PMID 39210722
2. [2]Isselbacher EM, et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines. Circulation, 2022.PMID 36322642
3. [3]Nienaber CA, et al. Randomized comparison of strategies for type B aortic dissection: the INvestigation of STEnt Grafts in Aortic Dissection (INSTEAD) trial. Circulation, 2009.PMID 19996018
4. [4]Nienaber CA, et al. Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial. Circ Cardiovasc Interv, 2013.PMID 23922146
5. [5]Brunkwall J, et al. Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic remodelling: 1 year results of the ADSORB trial. Eur J Vasc Endovasc Surg, 2014.PMID 24962744