Transesophageal echocardiography-based diagnosis of aortic dissection with intimal tear prolapsing components of the lamella into the left ventricle: a case description

Introduction

Aortic dissection is a perilous cardiovascular disease with a high mortality rate (1) and is classified into Stanford A and B types based on involvement of the ascending aorta (2). Emergency cases of Stanford A aortic dissection, if not promptly treated, results in a mortality rate between 1% and 2% per hour after onset and a near 50% mortality rate within 48 hours (3). Surgery is the most effective treatment. Additionally, with the development of imaging technology, research on aortic dissection has become more intuitive. Consequently, the clinical classification of aortic dissection has become more detailed and practical. In 2020, Rylski at al. from the Department of Cardiovascular Surgery at the Heart Center of the University of Freiburg, Germany, proposed the type-entry-malperfusion (TEM) classification of aortic dissection. The TEM classification of aortic dissection is based on the extension of the dissection, the entry site, and malperfusion of end organs (4,5). The hallmark symptom is sudden severe chest or back pain, but due to varying locations, progression rates, and pathological changes, about 8% of patients present with atypical symptoms, leading to frequent misdiagnosis (6,7). Contrast-enhanced computed tomography angiography (CTA) is crucial for diagnosis, but echocardiography, particularly bedside transthoracic echocardiography, is often used for emergency evaluation (1). However, echocardiography has limited accuracy in determining the extent of dissection, making it more valuable for assessing aortic valve involvement and aiding in preoperative preparations. Here, we report a case where bedside transthoracic echocardiography misdiagnosed aortic dissection involving the aortic valve, which was corrected by preoperative transesophageal echocardiography.

Case presentation

A 34-year-old male experienced sudden chest tightness and syncope 4 hours prior to arrival to hospital, awakening with continued chest tightness and profuse sweating. He had no chest pain, shortness of breath, dizziness, nausea, vomiting, abdominal pain, or history of hypertension, coronary artery disease, or diabetes. Bedside portable cardiac ultrasound revealed a significantly dilated ascending aorta with floating intima in the aortic arch (Figure 1A), leading to a diagnosis of Stanford A aortic dissection. The proximal ascending aorta showed no floating intima, but the long-axis view of the left ventricle revealed a membrane-like structure entering the left ventricle (Figure 1B), causing severe aortic valve regurgitation (Figure 1C). Transthoracic echocardiography suggested aortic dissection involving the aortic valve, resulting in aortic valve prolapse and severe regurgitation. After informed consent was obtained from the patient, emergency surgery was performed. Preoperative transesophageal echocardiography revealed complete intimal tear in the ascending aorta, causing incomplete closure of the aortic valve (Figure 1D). Intraoperative findings showed significant dilation and swelling of the proximal and distal ascending aorta. Exploration revealed a tear in the mid-ascending aorta, located between the aortic valve and the proximal edge of the brachiocephalic trunk opening, with the intima appearing desleeved. The patient did not exhibit signs of end-organ malperfusion. According to the TEM classification, this was categorized as type A E1M0 (4,5). Intraoperatively, the dissected intima appeared as a detached sheath (Figure 2), and due to timely intervention, the aortic valve itself showed no significant damage, and valve replacement was deemed unnecessary. The detached intimal piece was repositioned and reinforced with a long strip “sandwich” arrangement. The proximal anastomosis of the ascending aorta was trimmed, and a 26-mm artificial graft was anastomosed to the proximal aorta using 4-0 Prolene sutures. Postoperative transesophageal echocardiography showed normal aortic valve opening and closing with minimal regurgitation (Figure 3).

Figure 1 Preoperative echocardiographic findings. (A) Transverse section at the sternal notch with the floating intima visible in the aortic arch. (B) Long-axis section of the left ventricle showing a membranous structure at the aortic valve orifice protruding into the left ventricle. (C) Long-axis section of the left ventricle showing severe aortic valve regurgitation. (D) Transesophageal echocardiogram showing complete detachment of the intima in the ascending aorta, with movement back and forth between the aorta and the left ventricular outflow tract throughout the cardiac cycle.

Figure 2 Intraoperative visualization showed the aortic intima appearing detached in a sheath-like manner.

Figure 3 Postoperative TEE indicated normal opening and closing activity of the aortic valve, with only a small amount of regurgitation. TEE, transesophageal echocardiography.

All procedures performed in this study were in accordance with the ethical standards of the Institutional Ethics Committee of The First Affiliated Hospital of Ningbo University (approval number 2024-135RS) and with the Helsinki Declaration (as revised in 2013). Publication of this article and accompanying images was waived from patient consent according to ethics committee of The First Affiliated Hospital of Ningbo University.

Discussion

Aortic dissection occurs when the inner layer of the aortic wall ruptures, which allows blood to flow into the middle layer, forming a hematoma and separating the intima from the middle layer, creating a false lumen (8). CTA is essential for diagnosing aortic dissection, providing a complete view of the dissection location and morphological changes. However, its value in assessing aortic valve involvement is limited (9). Echocardiography, due to its simplicity and speed, is often used for emergency evaluation (1), but its ability to determine the extent of dissection is limited. Its primary value lies in assessing aortic valve involvement and assisting in preoperative preparations, including valve replacement.

The typical symptom of aortic dissection is sudden severe chest or back pain, but due to variable symptoms, approximately 8% of patients exhibit atypical symptoms, leading to frequent misdiagnosis (6). In this case, the clinical symptoms more closely resembled those of acute aortic valve insufficiency. This fact, combined with transthoracic echocardiography showing severe aortic valve regurgitation, made a misdiagnosis of aortic valve insufficiency more likely. The common ultrasound features of Stanford A aortic dissection include a significantly dilated ascending aorta, floating intimal tear visible in both long- and short-axis views, and the formation of true and false lumens with disrupted intimal echoes at the tear site. This patient’s rare presentation of intimal tear in the ascending aorta, coupled with clinical symptoms resembling acute aortic valve insufficiency, made the case challenging. Bedside examination revealed a membrane-like structure entering the left ventricle during diastole, resulting in aortic valve regurgitation. The short-axis view suggested a “two-leaf” appearance, seemingly consistent with congenital bicuspid aortic valve with valve prolapse. However, the absence of intimal detachment in the aortic lumen and the normal left ventricular size and membranous structure in the left ventricular outflow tract did not align with the diagnosis of congenital bicuspid aortic valve with valve prolapse. Further examination revealed a significantly dilated ascending aorta with intimal echoes swinging with blood flow, confirming the diagnosis of aortic dissection. When aortic dissection involves the aortic root, varying degrees of aortic valve regurgitation may occur, requiring differentiation from aortic valve lesions causing regurgitation (10). In some cases, the detached intima during diastole may enter the left ventricular outflow tract, resembling aortic valve prolapse, emphasizing the need for careful observation of the relationship between the detached intima and the valve during surgery. Bedside portable ultrasound, due to its lower resolution, may struggle with accurate diagnosis, highlighting the advantages of intraoperative transesophageal echocardiography. Intraoperative transesophageal echocardiography confirmed a complete intimal tear in the ascending aorta, which entered the left ventricle during diastole and returned to the aorta during systole, leading to incomplete closure of the aortic valve.

Conclusions

When transthoracic echocardiography reveals significant aortic valve regurgitation, intraoperative transesophageal echocardiography is crucial to investigate the regurgitation mechanism and assess aortic valve structure and damage for surgical decision-making. Due to the poor image quality of bedside portable machines, their results may not be reliable. In such cases, CTA and intraoperative transesophageal echocardiography offer clear advantages.

Acknowledgments

Funding: None.

Footnote

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-807/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures in this study were performed in accordance with the ethical standards of the institutional ethics committee of The First Affiliated Hospital of Ningbo University (approval number 2024-135RS) and with the Helsinki Declaration (as revised in 2013). Publication of this article and accompanying images was waived from patient consent according to ethics committee of The First Affiliated Hospital of Ningbo University.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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