{'fraction_non_alphanumeric': 0.04165283770328576, 'fraction_numerical': 0.009459010952538998, 'mean_word_length': 5.219814241486068, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Mechanisms of pseudo-quadricuspid aortic valve perforation with predominant eccentric aortic regurgitation

Figure 1 In the aortic short-axis view (A), the pseudo-cusp (asterisk) had a defect (arrow) which was determined as the ‘blood sack’ and its flow outlet (arrow) by simultaneous colour Doppler flow imaging. In the aortic long-axis view (B), the pseudo-cusp (asterisk) was recognized as a dissection of the non-coronary cusp belly in the setting of non-coronary cusp perforation (arrow). Biplane images (C ) helped visualize the torrential eccentric aortic regurgitation going through the ‘blood sack’ (arrow). A 3D transesophageal echocardiography reconstruction of the aortic long-axis view (D) clearly shows both the inlet (arrow) and outlet (curved arrow) of the ‘blood sack’ (asterisk). A 3D en face view of the aortic valve (E) enables a visualization of the non-coronary cusp perforation, which resembles the exact anatomy in the surgical finding (F ).

In the aortic short-axis view (A), the pseudo-cusp (asterisk) had a defect (arrow) which was determined as the 'blood sack' and its flow outlet (arrow) by simultaneous colour Doppler flow imaging. In the aortic long-axis view (B), the pseudo-cusp (asterisk) was recognized as a dissection of the non-coronary cusp belly in the setting of non-coronary cusp perforation (arrow). Biplane images (C) helped visualize the torrential eccentric aortic regurgitation going through the 'blood sack' (arrow). A 3D transesophageal echocardiography reconstruction of the aortic long-axis view (D) clearly shows both the inlet (arrow) and outlet (curved arrow) of the 'blood sack' (asterisk). A 3D en face view of the aortic valve (E) enables a visualization of the non-coronary cusp perforation, which resembles the exact anatomy in the surgical finding (F).
A 57-year-old man with a known 2-year history of aortic insufficiency was referred for surgery for severe aortic regurgitation (AR) and LV enlargement (LVE). Previous transthoracic echocardiography (TTE) reported aortic valve perforation (AVP) or quadricuspid aortic valve. He presented with dyspnoea on exertion (NYHA III). His blood pressure was 129/49 mmHg, and cardiac computed tomography showed abnormal subaortic structures and LVE (Supplementary material online, Figure S1), with no evidence of coronary artery disease. TTE demonstrated reduced LV function with an ejection fraction of 43%. The LV end-diastolic diameter (LVEDD) was 68 mm, and ascending aorta was 37 mm. Transesophageal echocardiography (TEE) of the mid-esophageal (ME) short-axis view mimicked the quadricuspid aortic valve (Supplementary material online, Figure S2 and Video 1). However, a standard commissure view of the aortic root confirmed normal anatomy (Supplementary material online, Figure S3 and Video 2). A more close observation of the pseudo-quadricuspid aortic valve suggested a defect in the belly of the non-coronary cusp (NCC) (Supplementary material online, Figure S2, arrow). Colour Doppler flow imaging (CDFI) presented well the flow convergence of the NCC perforation and torrential AR, which had formed a 'blood sack' in the 'pseudo-cusp' between the right coronary cusp (RCC) and NCC (Supplementary material online, Figure S4 and Video 3), and afterwards, the flow dropped into the LV outflow tract from another rupture of the sack ( Figure 1A, Supplementary material online, Video 4). The ME long-axis view clearly showed the two-layered NCC and blood sack ( Figure 1B, Supplementary material online, Video 5). Biplane imaging assisted in revealing the direction of the torrential eccentric AR ( Figure 1C, Supplementary material online, Video 6). Reconstruction of 3D TEE enabled visualization of the dissected NCC belly ( Figure 1D, Supplementary material online, Video 7) and associated perforation ( Figure 1E, Supplementary material online, Video 8), which resembled the exact anatomy as visualized by the surgeon performing a minimally invasive thoracoscopy procedure for mechanical valve replacement ( Figure 1F). Pathological findings confirmed a degeneration aetiology. He was on warfarin, and repeated TTE at the first 3-month follow-up showed an LVEDD of 55 mm and an LV ejection fraction of 62%.
Isolated aortic perforation with cusp dissection is an extremely rare aetiology for severe eccentric AR. Given that the aortic valve has sandwich-like three-layered components, such as the fibrosa (aortic side), spongiosa (inner layer), and ventricularis (ventricular side), 1,2 the dissection of the cusp may result from unbalanced sheer stress on the spongiosa. And the belly of the cusp is more vulnerable owing to its less spongiosa elastin than the hinge and coaptation regions. 3 We presented a predominant anatomical 'pocket' that mimicked quadricuspid aortic valves in short-axis view but was finally ruled out by using a 'region of interest'-derived scanning approach, i.e. by focusing the pseudo-cusp and rotating the probe on simultaneous biplane and CDFI modes. Our experience highlights that, in patients with severe eccentric AR and highly suspected AVP, multiplanar TEE, CDFI, and 3D TEE reconstruction should be applied sufficiently to assist the accurate diagnosis of the aortic anatomy and mechanisms of the regurgitation.

Lead author biography
Dr Zhenzhen Wang is an associate professor in Ultrasound Medicine at the Zhejiang Provincial People's Hospital. She graduated with an MD in Imaging and Nuclear Medicine from Harbin Medical University. She was a visiting research fellow for Cardiovascular Medicine at the Mayo Clinic from 2018 to 2020. She is currently a specialist in intraoperative transesophageal echocardiography and 3D reconstruction. She is a member of the European Society of Cardiology, the American Heart Association, and the American Society of Echocardiography and is a Craniocerebral Committee member of the China Society of Ultrasonic Medical Engineering.

Supplementary material
Supplementary material is available at European Heart Journal-Case Reports online.