Approach to the Patient with Acute Aortic Syndromes in Light of the New Consensus Statement on Multimodality Imaging in Thoracic Aortic Diseases

Abstract

Acute aortic syndromes comprise a range of interrelated conditions including aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, and contained or not contained aortic aneurysm rupture. These syndromes are potentially life threatening; therefore, a rapid and accurate diagnosis is crucial. A new Clinical Consensus Statement on Aortic and Peripheral Vascular Disease has recently been published, and we will try to highlight the main innovations in the document.

Keywords: Acute aortic syndromes; aortic dissection; multimodality imaging.

Figure 1

Examples of transthoracic views for the visualization of the aorta. (a) Parasternal long axis with visualization of the aortic root, sinotubular junction, and the proximal ascending aorta, (b) same view with an ideal scan of the ascending aorta (mildly dilated), (c) suprasternal window of the aortic arch, (d) descending thoracic and abdominal aorta from a subcostal window. AA = ascending aorta, LA = Left atrium, Ao = aorta

Figure 2

Examples of transthoracic views in cases with aortic dissection. Top panels: a-c of the same patient. (a) Parasternal long axis showing a flap in the proximal aorta (White Arrow: intimal flap between the true and the lase lumed), (b) the color Doppler confirms the presence of the flap with the flow entering into the true lumen (TL) (and a low flow into the false lumen [FL]), (c) Parasternal short axis clearly confirms and identifies the flap in the proximal aorta, (d and e) two cases in whom in the subcostal view the TL and FL are clearly detected. AA = ascending aorta, LA = Left atrium, LV = Left ventricular, TL = True lumen, FL = False lumen

Figure 3

Examples of transesophageal echocardiography in cases with aortic dissection. (a-c) A patient with Type A aortic dissection. (a) Short axis of the proximal ascending aorta showing the true lumen and the flap in diastole, Same view in a systolic frame showing the entry tear (arrow), (c) in the same view, the color Doppler clearly identifies the true lumen. (d-f) a second case with the intimal flap invaginating (arrow) into the aortic valve in diastole (a) and outlining the true lumen in systole without (e) and with (f) the color Doppler. Asc Ao = ascending aorta; LA = Left atrium, TL = True lumen, FL = False lumen

Figure 4

Examples of transesophageal echocardiography (TEE) in cases with aortic dissection. (a) TEE long axis with the identification of the flap and true lumen (TL), (b) in the same case, an upper TEE view of the distal ascending aorta and aortic arch shows a well-defined flow in the TL. (c and d) two examples of the descending aorta characterized, (c) By a smaller TL, with a larger false lumen that has inside a low flow characterized by a smoke-like effect, (d) a more circular TL due to a more pulsatile pressure. TL = True lumen, FL = False lumen

Figure 5

Classic Type A aortic dissection. (a) Volume rendering reconstruction shows intimal flap extending from the aortic root to the suprarenal aortic tract, (b-d) Axial computed tomography images show the intimal flap dividing true and false lumina along the entire course of the thoracic aorta. Note the primary intimal tear located at the level of ascending aorta (arrow). T = True, F = False

Figure 6

Top panels: Type A aortic dissection with involvement of right coronary artery (RCA). (A) Axial computed tomography (CT) scan shows a type A aortic dissection with aneurysmal dilatation of the ascending aorta, (B) Axial image clearly shows the origin of RCA from the false lumen (arrow), (C) Axial image shows the re-entry tear at the level of the distal aortic arch (arrowhead). Bottom panels: Type B aortic dissection. (A) Volume rendering CT reconstruction shows the dissection flap (arrowheads) extending through a markedly tortuous and aneurysmatic descending aorta, (B and C) Axial and oblique sagittal reconstructions show the aortic dissection at the level of the middle-distal tract of the descending aorta (arrowheads)

Figure 7

Cases with intramural hematomas. (a) Transesophageal echocardiography (TEE) log axis view of the ascending aorta. The lumen of the aorta is dilated without any flap and the anterior wall is markedly thickened (8 mm; arrows), (b) TEE long axis of the ascending aorta with an enlarged lumen and typically marked thickened posterior aortic wall; the yellow arrow indicates an intraparietal hemorrhage, (c) Short axis of the aortic root with focal, crescentic thickened aortic wall (asterisk and arrows), (d and e) In the same case, the TEE short and long axes of the descending thoracic aorta show marked thickening of the aortic walls. Ao = aorta

Figure 8

Type A acute intramural aortic hematoma. (a) Precontrast axial computed tomography (CT) image shows the high attenuation aortic wall thickening (white arrowheads) in the ascending aorta, (b and c) Postcontrast axial (b) and coronal (c) CT images illustrate the crescentic aortic wall thickening (black arrowheads) along the anterolateral surface of ascending aorta. A concomitant left pleural effusion (asterisk) is seen

Figure 9

Top panels: Descending aorta penetrating atherosclerotic ulcer at transesophageal echocardiography. Bottom panels: Penetrating atherosclerotic ulcer. Contrast-enhanced computed tomography (CT) (volume-rendering reconstruction), (A) Oblique sagittal reconstruction, (B) Axial CT images (C and D) show severe protruding atherosclerotic plaques (arrows) in the descending thoracic aorta, with a craterlike lesion in the lateral wall (arrowheads) consistent with penetrating atherosclerotic ulcer

Figure 10

Flowchart. Adapted from Evangelista et al.[1] Diagnostic algorithm for patients with suspicious acute aortic syndromes. The red arrows and red tiles underline the main novelties of this diagnostic work-up. *focus transthoracic echocardiography (TTE) oriented to rule out acute aortic disease, abnormal left ventricular motion, or pericardial effusion, **comprehensive TTE including evaluation of aortic valve, ventricular function, and pericardial effusion if not performed in Step II, ^Indicated only if experts in TOE are available or in patients under artificial ventilation and deep sedation/general anesthesia. AAS = Acute aortic syndromes, ECG = Electrocardiogram, TTE = Transthoracic echocardiography, CT = Computed tomography, TOE = Transesophageal echocardiography