Analysis of the international consensus on acute type B aortic intramural hematoma and penetrating ulcer（I）

On September 30th local time, the European Journal of Vascular and Endovascular Surgery (EUR J VASC ENDOVASC) published online: International expert consensus on the management of acute type B aortic intramural hematoma and penetrating ulcers.

The following is a comprehensive overview of the key elements of the international expert consensus on the management of acute type B intramural aortic hematoma and penetrating ulcers, along with a professional analysis based on recent advances.

Key contents are as follows:

Consensus Background and Research Methods: This document describes the spectrum of acute aortic syndromes, the limitations of current guidelines, and the Delphi expert consensus methodology employed.

Imaging and Risk Assessment Advances: This document details the optimization of imaging techniques, the new definitions of complexity and high-risk features, and compares guideline differences using tables.

Treatment Strategies and Technological Innovations: This document systematically describes drug therapy, TEVAR indications, technical key points, and follow-up protocols, including multiple tables with detailed technical information.

Consensus Value and Clinical Implications: This document evaluates the multidisciplinary collaborative value of the consensus, its limitations, and outlines future research directions.

1. Consensus Background and Research Methodology:
Acute aortic syndrome (AAS) is a group of life-threatening aortic emergencies, primarily encompassing classic aortic dissection, intramural hematoma (IMH), and penetrating aortic ulcer (PAU). While these conditions have distinct pathological underpinnings, they share a common characteristic: compromised aortic wall integrity, which can rapidly progress to aortic rupture or fatal complications. In recent years, advancements in imaging technology and the rapid development of endovascular surgery have led to a deeper understanding of acute type B intramural hematoma and penetrating ulcers. However, existing guidelines still contain inconsistencies or evidence gaps on many key clinical issues, leading to significant disparities in clinical practice.

Aortic Dissection, AD：

Intramural Hematoma, IMH

Penetrating Aortic Ulcer, PAU

1.1 Disease Definition and Limitations of Current Guidelines:
Aortic intramural hematoma (IMH) is defined as a hematoma within the aortic wall medial layer, without typical intimal tears or false lumen flow. It often occurs in association with rupture of the vasa vasorum or a minor intimal rupture. A penetrating aortic ulcer (PAU), on the other hand, results from the rupture of an atherosclerotic plaque, which penetrates the internal elastic layer into the medial layer and is often accompanied by surrounding hematoma formation. Despite distinct pathological mechanisms, clinical studies have shown that IMH and PAU share similar clinical presentations and can both acutely progress to aortic dissection or rupture. Notably, IMH accounts for approximately 5%-20% of all cases of acute aortic syndrome, while PAU accounts for approximately 2%-7.6%. However, over 45% of IMH cases may be accompanied by PAU.

Current major international guidelines, including those from the European Society for Vascular Surgery (ESVS), the American College of Cardiology/American Heart Association (ACC/AHA), and the European Association for Cardiothoracic Surgery/Society of Thoracic Surgeons (EACTS/STS), exhibit significant inconsistencies in the management of IMH and PAU. Recommendations differ particularly regarding key areas such as the definition of complex versus uncomplex disease, identification of high-risk features, and selection of intervention timing and modality. Most recommendations are based on low-quality evidence (Level C). This inconsistency is primarily due to the relative rarity of IMH and PAU, as most studies are retrospective, single-center designs, and lack support from large-scale randomized controlled trials.

1.2 Delphi Expert Consensus Study Methodology:

To address guideline gaps and resolve controversies in clinical practice, an international Delphi expert consensus panel, initiated by Squizzato and Piazza et al. from the University of Padova, Italy, systematically synthesized the experience of experts from high-volume aortic centers worldwide using a modified Delphi methodology. This study adhered strictly to the Delphi consensus methodology, with the following core design:
Expert Selection Criteria: 83 vascular and cardiovascular surgeons from Europe, North America, Latin America, Asia, and Oceania were recruited. All experts met strict inclusion criteria: ① publication in a high-impact cardiovascular journal; ② presentation at an international aortic disease conference; ③ service on the editorial board of a relevant journal; and ④ affiliation with a medical center with an annual TEVAR volume exceeding 15 and 24/7 service.

Consensus Development Process: A three-round Delphi process was conducted. In the first round, open-ended and multiple-choice questions were used to gather key clinical practice questions. In the second round, the resulting statements were evaluated using a four-point Likert scale (0 = completely disagree, 3 = completely agree). Finally, the revised statements were reviewed in the third round for strength confirmation. The entire process was conducted using the REDCap platform, ensuring the anonymity of expert responses and data accuracy.

Consensus criteria were defined as follows: Statements were categorized into four levels based on expert agreement: Level A (Very Strong): Complete agreement ≥75%; Level B (Strong): Complete agreement <75% but overall agreement ≥80% and complete disagreement <5%; Level C (Fair): Overall agreement <80% and complete disagreement ≥5%; Level D (Poor): Complete disagreement ≥10%. Only statements reaching Level A or B were included in the final consensus recommendations. Cohen’s kappa and intraclass correlation coefficient (ICC) were used to assess expert judgment consistency.

Finally, 83 experts (93% response rate) completed all three rounds of surveys. Their median age was 50 years. 70% were from Europe, 20% from North America, and the remainder from other regions. The experts ultimately reached consensus on 25 statements, of which 7 (28%) were grade A and 18 (72%) were grade B, forming a consensus on the full-process management of acute type B IMH and PAU from diagnosis, evaluation, treatment to follow-up.

2 Important Updates on Imaging and Risk Assessment:

Accurate imaging assessment and risk stratification are fundamental to the management of acute type B IMH and PAU and are key areas in which this consensus optimizes current clinical practice. Based on the latest imaging technologies and long-term follow-up data, the consensus experts have proposed more refined definitions of diagnostic criteria, complexity definitions, and high-risk features.

2.1 Optimization of Imaging Techniques and Establishment of Standards:

This consensus strongly recommends the use of electrocardiogram-gated thin-slice computed tomography angiography (CTA) as the preferred imaging modality for the diagnosis and follow-up of IMH and PAU (Grade B recommendation). Compared with conventional CTA, ECG gating effectively reduces aortic pulsation artifact and improves the sensitivity of detecting ulcer-like projections (ULPs) and intimal rupture. The scanning protocol should include dual-phase acquisition of both the arterial and venous phases to comprehensively assess the condition of the aortic wall and the extent of hematoma.

Notably, the consensus affirms the auxiliary role of intravascular ultrasound (IVUS) in TEVAR (Grade B recommendation), which can be used to determine the quality of the anchoring zone, accurately measure aortic diameter, and detect iatrogenic dissection. IVUS is particularly suitable for patients with renal insufficiency who cannot use contrast agents or those with complex aortic anatomy. It can provide real-time cross-sectional images of the aortic wall, accurately demonstrating the extent of the hematoma, ulcer location, and vessel wall structure.

Regarding imaging assessment parameters, the consensus emphasizes the importance of standardized measurement. For IMH, the focus should be on measuring the maximum hematoma thickness and extent involved; for PAU, the ulcer width, depth, and angle relative to the normal aortic wall should be accurately measured. Furthermore, experts recommend the use of three-dimensional reconstruction technology to assess the relationship between the lesion and important branch vessels to facilitate planning for possible TEVAR surgery.

2.2 Complexity and High-Risk Features:

The new consensus definition clearly distinguishes between “complex” and “high-risk” IMH/PAU, a significant revision to traditional guidelines. According to the consensus, complex lesions are limited to those with aortic rupture, refractory pain (persistent despite adequate analgesia), or refractory hypertension (inadequately controlled with combined beta-blockers and vasodilators) (Grade B recommendation). Pleural effusion, ulcer-like projection (ULP), and specific morphological criteria (such as PAU diameter >20 mm or depth >10 mm), which were often considered complications in some previous guidelines, are no longer considered solely as signs of complexity.

The definition of high-risk uncomplicated IMH/PAU is based on dynamic changes during serial imaging follow-up rather than a single baseline feature. For IMH, high-risk features include: ① Increased hematoma thickness; ② New ulcer-like projection or enlargement of existing ULP; and ③ Progression to typical aortic dissection (Grade A recommendation). For PAU, high-risk features include: ① new associated intramural hematoma; ② increased width or depth of the PAU; and ③ increased total aortic diameter (Grade A recommendation). These changes should be confirmed on at least two consecutive CTA examinations (2-14 days apart).

2.3 Genetic Testing and Precision Targeting of Biomarkers:

The consensus recommends genetic testing for screening of connective tissue diseases in specific populations, including: ① those with a family history of aortic disease; ② young patients (<50 years old); and ③ those with high-risk features but without typical atherosclerotic factors (Grade A recommendation). This recommendation reflects a deeper understanding of the role of genetic factors in aortic disease, particularly in young patients without significant traditional risk factors.

Regarding biomarkers, although these were not formally included in the consensus statement, cited data suggest that D-dimer, matrix metalloproteinase (MMP-9), and inflammatory markers (such as CRP and IL-6) show potential in risk assessment. Studies have shown that a D-dimer >5 μg/ml combined with MMP-9 >800 ng/ml can predict progression from PAU to type A dissection, with an area under the curve (AUC) of 0.92. In the future, multi-biomarker combinations may further enhance the accuracy of risk stratification.