Acute aortic dissection — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 59-year-old woman with Marfan syndrome presents to the emergency department with abrupt-onset, severe, tearing chest and back pain. Blood pressure (BP) is 168/94 mmHg in the right arm and 136/80 mmHg in the left arm; heart rate is 104 beats/min. She is not hypotensive, has no focal neurological deficit and no new murmur.^[1]

1. Using the 2024 European Society of Cardiology (ESC) algorithm, calculate her aortic dissection detection-risk score (ADD-RS), naming the three categories, and state her risk band and the next step. (3)^[1]
2. List the 2024 ESC Recommendation Table 44 rows on imaging in suspected acute aortic syndrome (AAS), with their class and level. (3)^[1]
3. Computed tomography (CT) confirms acute type B aortic dissection. State the 2024 ESC haemodynamic targets and first-line drugs with their class, and how the 2022 American College of Cardiology/American Heart Association (ACC/AHA) heart-rate target differs. (2)^[1][2]
4. What do the two guidelines say about the role of D-dimer? (2)^[1][2]

Model answers — SAQ 1

1. ESC 2024 Figure 30 scores 1 point for each of three categories: a high-risk condition (here Marfan syndrome), a high-risk pain feature (chest, back or abdominal pain described as abrupt onset, severe intensity, or ripping/tearing) and a high-risk examination feature (here a perfusion deficit, a differential systolic BP between arms).^[1] Her ADD-RS is 3; an ADD-RS of 2 or more is high risk, and the next step is cardiovascular CT (CCT) from neck to pelvis without delay and/or focused transthoracic echocardiography (TTE) plus electrocardiogram (ECG).^[1] Also creditable: ESC 2024 recommends a multiparametric algorithm for ruling in or out AAS using the ADD-RS in patients with clinical features compatible with possible AAS (Class I, Level B).^[1]
2. ECG-gated CCT from neck to pelvis is recommended as the first-line imaging technique in suspected AAS, since it is widely available, accurate and shows the entry tear, extension and possible complications (Class I, Level C).^[1] Focused TTE (with use of contrast if feasible) is recommended during the initial evaluation in suspected AAS (Class I, Level C).^[1] Transoesophageal echocardiography (TOE) is recommended for diagnosis and evaluation of the coeliac trunk and mesenteric artery in unstable patients who cannot be transferred to CCT (Class I, Level B), and, in suspected AAS, to guide peri-operative management and detect complications (Class I, Level C).^[1] In suspected AAS, cardiovascular magnetic resonance (CMR) should be considered as an alternative imaging technique if CCT is not available (Class IIa, Level C). Also creditable: in patients with clinical features compatible with possible AAS, a multiparametric algorithm using the ADD-RS is recommended (Class I, Level B).^[1]
3. ESC 2024 recommends immediate anti-impulse treatment targeting systolic BP (SBP) below 120 mmHg and heart rate 60 beats per minute (b.p.m.) or less, with a higher mean arterial pressure maintained in cases of spinal ischaemia or concomitant brain injury (Class I, Level B), and recommends intravenous beta-blockers (e.g. labetalol or esmolol) as first-line agents, with intravenous vasodilators (e.g. dihydropyridine calcium blockers or nitrates) that could be added if necessary (Class I, Level B).^[1] ACC/AHA 2022 says patients with AAS should be treated to a target heart rate of 60 to 80 bpm (b.p.m.), and to an SBP below 120 mm Hg or the lowest BP that maintains adequate end-organ perfusion (class of recommendation [COR] 1, level of evidence [LOE] C-LD).^[2] Also creditable: in all patients with acute type B dissection, ESC 2024 recommends medical therapy including pain relief and BP control (Class I, Level B), and says beta-blockers should be considered first-line medical therapy (Class IIa, Level B).^[1]
4. ESC 2024: laboratory tests should not delay imaging if the probability of dissection is high; D-dimer below 500 ng/mL makes dissection unlikely, and D-dimer is part of the low-risk branch of the ADD-RS algorithm.^[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, and combining a low risk score with a low D-dimer may be a useful strategy to exclude AAS.^[2]

SAQ 2 (10 marks)

Practice scenario. A 64-year-old man is on day 2 of acute type B aortic dissection treated medically. He has no known or suspected heritable thoracic aortic disease (HTAD).^[1]

1. List the features that make acute type B dissection complicated in 2024 ESC Figure 33. (3)^[1]
2. He develops abdominal pain with a rising lactate, and CT shows the superior mesenteric artery compromised by the dissection, consistent with mesenteric (organ) malperfusion. Thoracic endovascular aortic repair (TEVAR) anatomy is favourable: CT shows adequate proximal and distal landing zones and adequate iliac/femoral vessels for access. What does ESC 2024 recommend, with class? (2)^[1]
3. Had he stayed uncomplicated, name four high-risk features in ESC 2024 Figure 33; then give the ESC 2024 recommendation for TEVAR in uncomplicated acute type B with high-risk features, and the ACC/AHA 2022 recommendation for endovascular management in uncomplicated acute type B with high-risk anatomic features. (3)^[1][2]
4. After TEVAR, what imaging follow-up does ESC 2024 recommend if no abnormalities are found, and why is an early scan needed? (2)^[1]

Model answers — SAQ 2

1. ESC 2024 Figure 33: contained or free aortic rupture; organ malperfusion; extension of the dissection and progressive aortic enlargement, each on serial imaging in the acute phase during the hospital stay; refractory hypertension (ongoing hypertension despite more than three classes of antihypertensive drugs); refractory pain for more than 12 h.^[1] Also creditable: the ESC 2024 text says complicated acute type B includes aortic rupture, malperfusion-related issues, rapid aortic expansion, paraplegia/paraparesis, aortic haematoma, refractory pain and hypertension despite optimal therapy; the ACC/AHA 2022 consensus features (Table 27) are aortic rupture, branch artery occlusion and malperfusion, extension of dissection, aortic enlargement, intractable pain and uncontrolled hypertension.^[1][2]
2. Organ (mesenteric) malperfusion makes this complicated acute type B: ESC 2024 recommends emergency intervention (Class I, Level B) and TEVAR as first-line therapy (Class I, Level B), the footnote excepting known or suspected HTAD, which he does not have.^[1] Also creditable: ACC/AHA 2022 recommends intervention for acute type B with complications (COR 1, LOE C-LD) and says that with other complications, in the presence of suitable anatomy, endovascular approaches rather than open surgical repair are reasonable (COR 2a, LOE C-LD).^[2]
3. ESC 2024 Figure 33 high-risk features (any four), one of the following: high-risk features at CCT or cardiovascular magnetic resonance (CMR) — aortic diameter over 40 mm; false-lumen diameter over 20–22 mm; entry tear over 10 mm; entry tear at the lesser curvature; an increase in total aortic diameter of more than 5 mm on serial imaging in the acute phase during the hospital stay; haemorrhagic pleural effusion; evidence of malperfusion; high-risk clinical features — need for readmission; reappearance of pain/symptoms.^[1] ESC 2024: TEVAR in the subacute phase (between 14 and 90 days) should be considered in selected patients with uncomplicated acute type B and high-risk features to prevent aortic complications (Class IIa, Level B).^[1] ACC/AHA 2022: endovascular management may be considered in uncomplicated acute type B with high-risk anatomic features (COR 2b, LOE B-R); its Table 28 lists high-risk imaging findings — maximal aortic diameter over 40 mm, false-lumen diameter over 20–22 mm, entry tear over 10 mm, entry tear on the lesser curvature, increase in total aortic diameter of more than 5 mm between serial imaging studies, bloody pleural effusion and imaging-only evidence of malperfusion — and high-risk clinical findings — refractory hypertension despite more than 3 different classes of antihypertensive medication at maximal recommended or tolerated doses, refractory pain persisting more than 12 h despite maximal recommended or tolerated doses, and need for readmission.^[2]
4. ESC 2024 recommends imaging after TEVAR for AAS at 1, 6 and 12 months post-operatively, then yearly until the fifth post-operative year if no abnormalities are documented (Class I, Level B); abnormalities include pseudo-aneurysm, graft infection, endoleak (any type), enlargement of the excluded aneurysm, and stent graft migration, separation or fracture.^[1] ESC 2024 says the early 1-month control is necessary to exclude asymptomatic TEVAR-induced retrograde type A dissection, 70% of which occur within 30 post-operative days.^[1] Also creditable: ESC 2024 says that if no complications (as defined above) occur within the first 5 years, CCT every 2 years thereafter should be considered (Class IIa, Level B).^[1]