Challenges in Diagnosis of Non-A Non-B Acute Aortic Dissection

BACKGROUND

Non-A non-B (NANB) aortic dissections are uncommon and frequently unrecognized diseases. However, their proper identification is crucial given the unpredictable behavior of the dissected aorta with potential mortality and increased morbidity. We investigate the accuracy of radiological computed tomography angiography (CTA) reports in the diagnosis of acute NANB and the risk related to delayed recognition or misdiagnosis.

METHODS

The pretreatment contrast CTA of all consecutive patients admitted with acute aortic dissection (AAD) in a University Hospital in London (UK) between January 2017 and May 2023 were reviewed to retrospectively verify the accuracy of CTA reports in the diagnosis of NANB AAD (B1-2D The risk related to the delayed diagnosis (morbidity, mortality, and hospital readmissions) were evaluated as secondary outcomes. The study was conducted according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines.

RESULTS

Overall, 588 aortic CTAs were reviewed for a total of n = 393 (66.8%) type A AADs, n = 171 (29%) type B AADs and n = 25 (4.3%) NANB AADs (n = 16, 64% men, mean age 60.56, standard deviation ± 14.6 years). While no case of misdiagnosis was identified in Type A or B AAD groups, in NANBs only about a third of cases (n = 9, 36%) were immediately indicated as "NANB" (n = 2, 8%) or "B with retrograde extension into the arch" (n = 7, 28%), n = 8 cases (32%) were described generically as "arch dissections" (n = 6, 24%) or "type A and B" AAD (n = 2, 8%). The remaining 32% of patients received a diagnosis that did not include mention of the arch, as n = 6 (24%) cases were reported to be "type A″ and n = 2 (8%) to be "type B″ AADs. Despite the heterogeneity of terms used to describe NANB AAD, no case of cardiac tamponade, new onset malperfusion nor neurological complications were reported, and no sudden death nor home-discharge and readmission while waiting for the proper diagnosis.

CONCLUSIONS

The heterogeneity of terms used to describe NANB aortic dissection highlights the need for increased awareness, adoption of in guideline based classification systems, and further education to better understand and correctly address this challenging entity, minimizing misdiagnosis in ambiguous or difficult cases.

Total aortic arch debranching with antegrade Thoracic Endovascular Aortic Repair (TEVAR) in acute non-A non-B aortic dissection

BACKGROUND

The surgical evaluation and management of non-A non-B aortic dissections, in the absence of ascending aortic involvement, remains a grey area. It is in these scenarios when thorough evaluation of patient/family history, clinical presentation, but also overall lifestyle, is of immense importance when determining an optimal intervention.

CASE PRESENTATION

We present a 38-year-old patient with a physically demanding lifestyle as a professional wrestler, uncontrolled hypertension due to history of medical non-adherence, and family history of aortic dissection who presented with acute non-A non-B aortic dissection. He was spared a total arch replacement by undergoing a hybrid approach of complete aortic debranching with antegrade Thoracic Endovascular Aortic Repair (TEVAR). The patient was able to benefit from reduced cardiopulmonary bypass (CPB) time, avoidance of aortic cross clamp, circulatory arrest, and hypothermic circulation.

CONCLUSIONS

This patient's unique composition of a physically demanding lifestyle, personal history of medical non-adherence, family history of aortic dissection, and clinical presentation required a holistic approach to understanding an ideal intervention that would be best suited long-term. Due to this contextualization, the patient was able to be spared a total arch replacement, or suboptimal medical management, by instead undergoing a hybrid-approach with total aortic arch debranching with antegrade TEVAR.

TEM Classification of Aortic Dissection-The Evolving Scoring System: A Literature Review

Aortic dissection is an acute presentation that, if unnoticed, poses a significant risk to life. Anatomically, it is defined as a tear in the intimal layer of the aorta, but management differs significantly based on the location of this tear. Traditionally the Stanford and DeBakey classifications have been used to distinguish tear types and thus guide the most favourable management option, be it medical optimisation or surgery. Recently, a new Type-Entry-Malperfusion classification has been proposed to more accurately define and thus risk stratify patients with aortic dissection. This review summarises the Type-Entry-Malperfusion classification and highlights its potential advantages and limitations compared to other classifications. Clinical insights and potential barriers to adopting this classification are also described in this review.

Non-A Non-B Acute Aortic Dissection: Is There Some Confusion in the Radiologist's Mind?

BACKGROUND

The aim of this study is to define and determine the rate of acute non-A-non-B aortic dissections, and to evaluate CT angiography findings and possible complications, as well as to discuss management strategies and currently available therapy. Non-A non-B type of aortic dissection is still a grey area in the radiologist's mind, such that it is not entirely clear what should be reported and completed in terms of this disease.

METHODS

A retrospective single-center study including 36 pre-treatment CT angiograms of consecutive patients (mean age: 61 years) between January 2012 and December 2022 with aortic dissection involving the aortic arch with/without the thoracic descending/abdominal aorta (type non-A non-B).

RESULTS

According to the dissection anatomy, we identified three modalities of spontaneous acute non-A-non-B anatomical configurations. Configuration 1 (n = 25) with descending-entry tear and retrograde arch extension (DTA entry). Configuration 2 (n = 4) with Arch entry tear and isolated arch involvement (Arch alone). Configuration 3 (n = 7) with Arch entry and anterograde descending (±abdominal) aorta involvement (Arch entry). CT angiogram findings, management, and treatment options are described.

CONCLUSIONS

Acute non-A non-B dissection represents an infrequent occurrence of aortic arch dissection (with or without involvement of the descending aorta) that does not extend to the ascending aorta. The complete understanding of its natural progression, distinct CT angiography subtypes, optimal management, and treatment strategies remains incomplete. Within our series, patients frequently exhibit a complex clinical course, often necessitating a more assertive approach to treatment compared to type B dissections.

Surgical treatment patterns and clinical outcomes of type B aortic dissection involving the aortic arch

OBJECTIVE

In the present report, we have described the outcomes of endovascular repair, hybrid arch repair, and open surgical repair for type B dissection involving the aortic arch (B_{1-2, D}).

METHODS

Cases of endovascular repair, hybrid arch repair, and open surgical repair performed between January 2015 and December 2019 for aortic dissection designated as B_{1-2, D} by the Society for Vascular Surgery/Society of Thoracic Surgeons classification were retrospectively analyzed. The primary end point was all-cause mortality at follow-up. The secondary end points included early mortality, early morbidities, and aortic-related late events. Kaplan-Meier curves were created to analyze survival from all-cause mortality and freedom from aortic-related late events in the endovascular, hybrid, and open groups. Propensity score matching and stratification (stratified by proximal dissection extension: B_{1, D} and B_{2, D}) were performed as sensitivity analyses to compare the outcomes among the three treatment patterns after controlling for major confounders.

RESULTS

The present study included 151 patients (men, 79.5%; mean age, 47.3 ± 10.5 years), with 72 (47.7%) in the endovascular group, 46 (30.5%) in the hybrid group, and 33 (21.8%) in the open group. No significant difference was noted in early mortality between the endovascular, hybrid, and open groups (1.4% vs 2.2% vs 3.0%; P = .791). The incidence of early endoleak was significantly greater (33.3% vs 13.0% vs 6.1%; P = .002) and the incidence of renal function deterioration was less (4.2% vs 26.1% vs 24.2%; P = .001) after endovascular repair vs hybrid arch repair and open surgery. After a median follow-up of 40.0 months (range, 0-84.0 months), no significant differences were found in all-cause mortality (5.6% vs 4.3% vs 3.0%; P = 1.0), aortic-related late events (16.7% vs 15.2% vs 12.1%; P = .834), or late endoleak (9.7% vs 4.3% vs 6.1%; P = .630) after endovascular, hybrid, and open surgery. The propensity score matching and stratification analyses displayed consistent outcomes for early mortality, all-cause mortality, and aortic-related late events among the three groups.

CONCLUSIONS

The mid- to long-term outcomes after endovascular repair, hybrid arch repair, and open surgical repair for type B dissection involving the aortic arch (B_{1-2, D}) were favorable and comparable in selected patients. Extensive experience and multidisciplinary teamwork are prerequisites for individualized strategies for repair of B_{1-2, D}.

Arterial dissections: Common features and new perspectives

Arterial dissections, which involve an abrupt tear in the wall of a major artery resulting in the intramural accumulation of blood, are a family of catastrophic disorders causing major, potentially fatal sequelae. Involving diverse vascular beds, including the aorta or coronary, cervical, pulmonary, and visceral arteries, each type of dissection is devastating in its own way. Traditionally they have been studied in isolation, rather than collectively, owing largely to the distinct clinical consequences of dissections in different anatomical locations - such as stroke, myocardial infarction, and renal failure. Here, we review the shared and unique features of these arteriopathies to provide a better understanding of this family of disorders. Arterial dissections occur commonly in the young to middle-aged, and often in conjunction with hypertension and/or migraine; the latter suggesting they are part of a generalized vasculopathy. Genetic studies as well as cellular and molecular investigations of arterial dissections reveal striking similarities between dissection types, particularly their pathophysiology, which includes the presence or absence of an intimal tear and vasa vasorum dysfunction as a cause of intramural hemorrhage. Pathway perturbations common to all types of dissections include disruption of TGF-β signaling, the extracellular matrix, the cytoskeleton or metabolism, as evidenced by the finding of mutations in critical genes regulating these processes, including LRP1, collagen genes, fibrillin and TGF-β receptors, or their coupled pathways. Perturbances in these connected signaling pathways contribute to phenotype switching in endothelial and vascular smooth muscle cells of the affected artery, in which their physiological quiescent state is lost and replaced by a proliferative activated phenotype. Of interest, dissections in various anatomical locations are associated with distinct sex and age predilections, suggesting involvement of gene and environment interactions in disease pathogenesis. Importantly, these cellular mechanisms are potentially therapeutically targetable. Consideration of arterial dissections as a collective pathology allows insight from the better characterized dissection types, such as that involving the thoracic aorta, to be leveraged to inform the less common forms of dissections, including the potential to apply known therapeutic interventions already clinically available for the former.

Development and validation of a nomogram to predict postoperative delirium in type B aortic dissection patients underwent thoracic endovascular aortic repair

Objective

Postoperative delirium (POD) is a common postoperative complication after cardiovascular surgery with adverse outcomes. No prediction tools are currently available for assessing POD in the type B aortic dissection (TBAD) population. The purposes of this study were to develop and validate a nomogram for predicting POD among TBAD patients who underwent thoracic endovascular aortic repair (TEVAR).

Methods

The retrospective cohort included 631 eligible TBAD patients who underwent TEVAR from January 2019 to July 2021. 434 patients included before 2021 were in the develop set; 197 others were in the independent validation set. Least absolute shrinkage and selection operator (LASSO) and logistic regression were applied to identify the most useful predictive variables for constructing the nomogram. Discrimination and the agreement of the model was assessed with the area under the receiver operating characteristic curve (AUC), Brier score and the Hosmer-Lemeshow goodness-of-fit test. The results were validated using a bootstrap resampling and the validation set.

Results

The incidence rate of POD observed in the development and validation cohort were 15.0% and 14.2%, respectively. Seven independent risk factors, including age ≥60 years, syncope or coma, postoperative blood transfusion, atelectasis, estimated glomerular filtration rate (eGFR) <80 ml/min/1.73 m2, albumin <30 g/L, and neutrophil to lymphocyte ratio, were included in the nomogram. The model showed a good discrimination with an AUC of 0.819 (95% CI, 0.762–0.876) in the developed set, and adjusted to 0.797 (95% CI, 0.735–0.849) and 0.791 (95% CI, 0.700–0.881) in the internal validation set and the external validation, respectively. Favorable calibration of the nomogram was confirmed in both the development and validation cohorts.

Conclusion

The nomogram based on seven readily available predictors has sufficient validity to identify POD risk in this population. This tool may facilitate targeted initiation of POD preventive intervention for healthcare providers.

“More or less”: management of type A aortic dissections in the endovascular era

The management of type A aortic dissection presents a major therapeutic challenge in modern surgical practice. Whilst the traditional dictum, to provide timely surgical intervention with the minimum treatment needed to repair the ascending aorta as well as the primary tear, may be a reasonable strategy in older patients, a tailored approach is desired for younger patients to manage the immediate life-threatening condition, as well as for the management of lifelong complications of the residual dissected aorta. Endovascular technology continues to advance, providing an adjunctive role to open cardiac repair presently to manage downstream aortic pathology, with the aim of striving towards a complete endovascular solution for type A aortic dissections.

CT of the Difficult Acute Aortic Syndrome

Acute aortic syndrome (AAS) is classically attributed to three underlying pathologic conditions-aortic dissection (AD), intramural hematoma (IMH), and penetrating atherosclerotic ulcer (PAU). In the majority of cases, the basics of image interpretation are not difficult and have been extensively reviewed in the literature. In this article, the authors extend existing imaging overviews of AAS by highlighting additional factors related to the diagnosis, classification, and characterization of difficult AAS cases. It has been well documented that AAS is caused not only by an AD but by a spectrum of lesions that often have overlap in imaging features and are not clearly distinguishable. Specifically, phase of contrast enhancement, flow artifacts, and flapless AD equivalents can complicate diagnosis and are discussed. While the A/B dichotomy of the Stanford system is still used, the authors subsequently emphasize the Society for Vascular Surgery's new guidelines for the description of acute aortic pathologic conditions given the expanded use of endovascular techniques used in aortic repair. In the final section, atypical aortic rupture and pitfalls are described. As examples of pericardial and shared sheath rupture become more prevalent in the literature, it is important to recognize contrast material third-spacing and mediastinal blood as potential mimics. By understanding these factors related to difficult cases of AAS, the diagnostic radiologist will be able to accurately refine CT interpretation and thus provide information that is best suited to directing management. Online supplemental material is available for this article. ^©RSNA, 2021.

ACR Appropriateness Criteria® Suspected Acute Aortic Syndrome

Acute aortic syndrome (AAS) includes the entities of acute aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer. AAS typically presents with sudden onset of severe, tearing, anterior, or interscapular back pain. Symptoms may be dominated by malperfusion syndrome, due to obstruction of the lumen of the aorta and/or a side branch when the intimal and medial layers are separated. Timely diagnosis of AAS is crucial to permit prompt management; for example, early mortality rates are reported to be 1% to 2% per hour after the onset of symptoms for untreated ascending aortic dissection. The appropriateness assigned to each imaging procedure was based on the ability to obtain key information that is used to plan open surgical, endovascular, or medical therapy. This includes, but is not limited to, confirming the presence of AAS; classification; characterization of entry and reentry sites; false lumen patency; and branch vessel compromise. Using this approach, CT, CTA, and MRA are all considered usually appropriate in the initial evaluation of AAS if those procedures include intravenous contrast administration. Ultrasound is also considered usually appropriate if the acquisition is via a transesophageal approach. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A New Aortic Arch Dissection Classification: The Fuwai Classification

Aims: We describe a new aortic arch dissection (AcD) classification, which we have called the Fuwai classification. We then compare the clinical characteristics and long-term prognoses of different classifications.

Methods: All AcD patients who underwent surgical procedures at Fuwai Hospital from 2010 to 2015 were included in the study. AcD procedures are divided into three types: Fuwai type Cp, Ct, and Cd. Type Cp is defined as the innominate artery or combined with the left carotid artery involved. Type Cd is defined as the left subclavian artery or combined with the left carotid artery involved. All other AcD surgeries are defined as type Ct. The Chi-square test was adopted for the pairwise comparison among the three types. Kaplan-Meier was used for the analysis of long-term survival and survival free of reoperation.

Results: In total, 1,063 AcD patients were enrolled from 2010 to 2015: 54 patients were type Cp, 832 were type Ct, and 177 were type Cd. The highest operation proportion of Cp, Ct and Cd were partial arch replacement, total arch replacement, and TEVAR. The surgical mortality in type Ct was higher compared to type Cd (Ct vs. Cd = 9.38 vs. 1.69%, p < 0.01) and type Cp (Ct vs. Cp = 9.38 vs. 1.85%, p = 0.06). There was no difference in surgical mortality of type Cp and Cd (p = 0.93). There were no significant differences in the long-term survival rates (p = 0.38) and free of aorta-related re-operations (p = 0.19).

Conclusion: The Fuwai classification is used to distinguish different AcDs. Different AcDs have different surgical mortality and use different operation methods, but they have similar long-term results.

Emergency CT misdiagnosis in acute aortic syndrome

OBJECTIVES

This cross-sectional study assessed the accuracy of emergency CT reports at presentation in acute aortic syndrome (AAS).

METHODS

Retrospective identification of cases of AAS presenting within a large health board with three acute hospitals receiving adult patients between January 2013 and December 2016. CT studies and reports at presentation were reviewed for discrepancies related to diagnosis, complications and classification by two cardiovascular radiologists. The specialist interest of the original reporters, clinically suspected diagnosis at referral for CT and technical adequacy of the scans were also assessed. False-positive diagnoses were identified and evaluated separately.

RESULTS

Among 88 consecutive confirmed cases of AAS at least one discrepancy was identified in 31% (n = 27), including failure to identify or misinterpretation of the AAS itself in 15% (n = 13), haemorrhage in 13% (n = 11), branch involvement in 9% (n = 8), and misclassification in 3% (n = 3). All discrepancies occurred among the 80% (n = 70) of cases reported by radiologists without specialist cardiovascular interest. 26% (n = 23/88) of AAS cases were not clinically suspected at referral for CT and although this was associated with suboptimal protocols, only 51% of CT scans among suspected cases were technically adequate. Seven false-positive diagnoses were identified, three of which related to motion artefact.

CONCLUSION

Significant discrepancies are common in the emergency CT assessment of positive cases AAS and this study highlights important pitfalls in CT technique and interpretation. The absence of discrepancies among radiologists with specialist cardiovascular interest suggests both suspected and confirmed cases warrant urgent specialist review.

ADVANCES IN KNOWLEDGE

CT angiography is central to the diagnosis of AAS; however, significant radiology discrepancies are common among non-specialists. This study highlights important pitfalls in both CT technique as well as interpretation and supports routine specialist cardiovascular imaging input in the emergency assessment of AAS.

Acute aortic dissection with entry tear at the aortic arch: long-term outcome

OBJECTIVES

The goal was to evaluate outcomes after conservative or surgical treatment of acute aortic arch dissections.

METHODS

Between January 2009 and December 2018, patients with a diagnosis of acute aortic dissection were analysed. Aortic arch aortic dissection was defined as a dissection with an isolated entry tear at the aortic arch with no involvement of the ascending aorta.

RESULTS

Aortic arch dissection was diagnosed in 31 patients (age 59 ± 11 years). Surgical intervention was performed in 13 (41.9%) cases. Overall in-hospital mortality was 3% (n = 1), and all deaths occurred in the conservative group (n = 1; 6%), whereas the overall stroke rate was 3% (n = 1), and all strokes occurred in the group treated surgically (n = 1; 8%). Surgical repair was necessary for the following conditions: end-organ malperfusion (n = 9; 69%), impending rupture (n = 3; 23%) and dilatation of the aorta with ongoing pain refractory to medical treatment (n = 1; 8%). Overall survival at the end of the follow-up period was 71%, with 77% in the surgical group and 63% in the conservative group (P = 0.91). Freedom from surgical intervention was 71%, with 82% in the surgical and 63% in the conservative group (P = 0.21), and freedom from a neurological event was 88%, with 89% versus 89% (P = 0.68) in the surgical and conservative groups, respectively.

CONCLUSIONS

Aortic arch dissection is a rare pathological condition that is one of the most challenging decision-making entities. Patients manifesting an uneventful course not requiring a surgical intervention during a hospital stay were at a higher risk for aorta-related intervention during the follow-up period. The treatment modality had no impact on survival or on the incidence of a neurological event.

Computed Tomography Angiography Assessment of Acute Aortic Syndromes: Classification, Differentiating Imaging Features, and Imaging Interpretation Pitfalls

An acute aortic syndrome (AAS) is an important life-threatening condition that requires early detection and management. Acute intramural hematoma (IMH), aortic dissection (AD) and penetrating atherosclerotic ulcer (PAU) are included in AAS. ADs can be classified using the well-known Stanford or DeBakey classification systems. However, these classification systems omit description of arch dissections, anatomic variants, and morphologic features that impact outcome. The Society for Vascular Surgery and Society of Thoracic Surgeons (SVS-STS) have recently introduced a classification system that classifies ADs according to the location of the entry tear (primary intimomedial tear, PIT) and the proximal and distal extent of involvement, but does not include description of all morphologic features that may have diagnostic and prognostic significance. This review describes these classification systems for ADs and other AAS entities as well as their limitations. Typical computed tomography angiography (CTA) imaging appearance and differentiating features of ADs, limited intimal tears (LITs), IMHs, intramural blood pools (IBPs), ulcer-like projections (ULPs), and PAUs will be discussed. Furthermore, this review highlights common imaging interpretation pitfalls, what should be included in a comprehensive CTA report, and provides a brief overview of current management options.

Aortic aneurysm disease-Make room for chronobiology

BACKGROUND

Aortic aneurysm (AA) is a common atherosclerotic condition, accounting for nearly 6000 deaths in England and up to 175,000 deaths globally each year. The pathological outward bulging of the aorta typically results from atherosclerosis or hereditary connective tissue disorders. AAs are usually asymptomatic until spontaneous rupture or detected on incidental screening. Eight in 10 patients do not survive the rupture and die either before reaching hospital or from complications following surgery. Similar to other cardiovascular pathologies, AA is thought to be subject to chronobiological patterns of varying incidence.

METHODS

We performed a literature review of the current literature to evaluate the association between circadian rhythms, seasonal variations, and genetic factors and the pathogenesis of AA, reviewing the impact of chronobiology.

RESULTS

The incidence of AA is found to peak in the early morning (6-11 a.m.) and colder months, and conversely troughs towards the evening and warmer months, exhibiting a similar pattern of chronobiological rhythm as other cerebrovascular pathologies, such as myocardial infarcts, or cerebrovascular strokes.

CONCLUSION

Literature suggests there exists a clear relationship between chronobiology and the incidence and pathogenesis of ruptured AA; incidence increases in the morning (6-11 a.m.), and during colder months (December-January). This is more pronounced in patients with Marfan syndrome, or vitamin D deficiency. The underlying pathophysiology and implications this has for chronotherapeutics, are also discussed. Our review shows a clear need for further research into the chronotherapeutic approach to preventing ruptured AA in the journey towards precision medicine.

Chest CT Angiography for Acute Aortic Pathologic Conditions: Pearls and Pitfalls

Chest CT angiography (CTA) is essential in the diagnosis of acute aortic syndromes. Chest CTA quality can be optimized with attention to technical parameters pertaining to noncontrast imaging, timing of contrast-enhanced imaging, contrast material volume, kilovolt potential, tube-current modulation, and decisions regarding electrocardiographic-gating and ultra-fast imaging, which may affect the accurate diagnosis of acute aortic syndromes. An understanding of methods to apply to address suboptimal image quality is useful, as the accurate identification of acute aortic syndromes is essential for appropriate patient management. Acute aortic syndromes have high morbidity and mortality, particularly when involving the ascending aorta, and include classic aortic dissection, penetrating atherosclerotic ulcer, and acute intramural hematoma. An understanding of the pathogenesis and distinguishing imaging features of acute aortic syndromes and aortic rupture and some less common manifestations is helpful when interpreting imaging examinations. Related entities, such as ulcerated plaque, ulcerlike projections, and intramural blood pools, and mimics, such as vasculitis and aortic thrombus, are important to recognize; knowledge of these is important to avoid interpretive pitfalls. In addition, an awareness of postsurgical aortic changes can be useful when interpreting CTA examinations when patient history is incomplete. The authors review technical considerations when performing CTA, discuss acute aortic syndromes, and highlight diagnostic challenges encountered when interpreting aortic CTA examinations. ^©RSNA, 2021.

Non-A non-B aortic dissection: A literature review

Non-A non-B aortic dissections are an infrequent occurrence and represent a small proportion of aortic dissections. Treating this life-threatening medical emergency often requires surgeons to undertake some one of the most challenging surgical or endovascular cases in medicine. This literature review aims to define and classify non-A non-B dissections, describe their epidemiology as well as their pathology. This review also aims to discuss the range of surgical techniques employed in their treatment and management and to investigate the patient outcomes associated with each technique.

Association of renal cyst and type A acute aortic dissection with hypertension

Background

Type A acute aortic dissection (TA-AAD) has high mortality, with 50% of patients dying before hospital admission. Hypertension is the most common comorbidity for acute aortic dissection, and effective antihypertensive therapy is still unable to predict the risk of aortic rupture at the medium- and long-term stages. While the presence of renal cyst has been found to increases the risk of thoracic aortic disease, the correlation between renal cyst and TA-AAD with hypertension remains poorly understood. Thus, this study aimed to determine the relationship of renal cyst and TA-AAD with hypertension.

Methods

A retrospective analysis was performed in 464 hypertension patients from August 2014 to August 2019. A total of 230 TA-AAD patients were enrolled in the AD with hypertension group (age 53.79±11.31 years, male 90.87%), and matched by age, sex, and hypertension control to 234 patients without TA-AAD who were enrolled in the non-AD with hypertension group. Patients were divided into three subgroups according to the numbers of renal cysts: no renal cyst, single renal cyst, and multiple renal cysts.

Results

In this study, the AD with hypertension group had significantly more single renal cyst and multiple renal cyst cases than did the non-AD with hypertension group. The mean age of the multiple renal cyst subgroup was significantly older than that of the single renal cyst subgroup (57.25±13.00 vs. 51.57±10.75 years) in the AD with hypertension group. There was significantly different distribution of dissection starting points and dissection ending points across three renal cyst subgroups. Multivariate logistic regression analysis indicated that having no renal cyst significantly decreased the risk of TA-AAD in middle-aged and elderly patents, but showed no correlations with those of younger ages. Single renal cyst status also significantly decreased the risk of TA-AAD in elderly patients [odds ratio (OR) =0.129, 95% confidence interval (CI): 0.029–0.575, P=0.007].

Conclusions

Renal cyst status correlates with the risk of TA-AAD with hypertension in middle-aged and elderly patients, and exhibits different degrees of vascular lesion in aortic dissection. We therefore suggest that different antihypertensive standards should be adopted in different renal cyst status to more effectively prevent aortic dissection.

Exercise parameters for the chronic type B aortic dissection patient: a literature review and case report

INTRODUCTION

The conservative management of a Stanford type B aortic dissection (TBD) is optimal blood pressure management, cardiac rehabilitation, and progressive return to activities of daily living (ADL) while preventing advancing dissection and aortic dilation. Recent case reports indicate higher levels of activity may be safe; however, the exercise parameters for chronic TBD conditions span a broad range and the research is limited.

CASE PRESENTATION

The clinical presentation and outpatient cardiac and physical rehabilitation program for a 61-year-old male with a chronic TBD from his subclavian artery to common iliac arteries is presented. The exercise protocol was developed and based on the available literature for the management of chronic aortic diseases. Eighteen months after the patient's acute TBD event, he began an exercise protocol designed to address the sport specific functional deficits related to his recreational activities. The program incorporated a variety of exercises from resistance training to cardiovascular exercise and high interval training. The therapeutic goals included restoration of cardiac fitness and improvement of core stability and appendicular strength, ultimately aiming toward a potential to return to recreational sport involving short duration, high intensity activity.

CONCLUSION

In conjunction with the appropriate anti-hypertensive medication treatment, understanding the concepts of aortic hemodynamics as they relate to exercise can serve as a guideline for clinicians in developing an individualized exercise program for their TBD patients. Moreover, these physical training programs may include particular exercise guidelines beyond general recommendations of light to moderate cardiovascular activities.

Off-Label Treatment With Transfemoral Bare Stents for Isolated Aortic Arch Dissection

BACKGROUND

Aortic arch dissection is a catastrophic acute event involving the aorta. Its accurate diagnosis and treatment are mandatory to optimize patient outcome. We aimed to assess the efficacy and safety of endovascular treatment with transfemoral bare stents of isolated aortic arch dissection as a valid alternative in patients unsuitable for conventional surgery.

METHODS

In this case series, we report our experience with 3 patients affected by isolated aortic arch dissection treated with endovascular surgery from February 2019 to May 2019. All patients were associated with severe comorbidities emergently referred at our center. Vascular access was achieved by surgical exposure of the right common femoral artery performed under general anesthesia. All patients were observed for at least 3 months.

RESULTS

All patients were treated in a hybrid operative room with transfemoral implantation of a bare metal Jotec E-XL stent released in the aortic arch. The postoperative period was uneventful, and all 3 patients were discharged or transferred on the fourth postoperative day. At follow-up, computed tomography scans showed good results in all patients.

CONCLUSIONS

A purely endovascular approach to located aortic arch dissections, with bare stents, remains challenging, although it has been proven to be a valid alternative treatment in some off-label cases.

Gaussian Surface Curvature Mapping Indicating High Risk Type B Thoracic Aortic Dissections

BACKGROUND

Identifying fragile aortas that are more likely to lead to adverse clinical outcomes would provide surgeons with a better sense of how to balance the risks of surgical versus medical management in patients with type B dissections. We examine the progression of a type B dissection into a type A dissection in a patient and analyze changes in the Gaussian surface curvature distribution, as well as the response of the stress distribution at the lesser curve in response to pressurization. We hypothesize that examining the Gaussian curvature will provide us with a link between aortic surface geometry and the stress distribution, which is crucial to understanding the process driving aortic dissection.

METHODS

Computed tomography scans of a patient before and after the type A dissection are obtained. These are segmented in Simpleware ScanIP. Centerline curvatures are calculated on segmented models in ScanIP. Models are then pressurized in the finite element analysis software Abaqus. The Gaussian curvature is calculated by exporting segmentations into the computational program Matlab and applying a modified previously published algorithm.

RESULTS

The centerlines generated in ScanIP fail to capture the change in the acuity of the lesser curve before and after the type A dissection. Instead, Gaussian curvature analysis shows that the curvature distribution before the type A dissection is much wider compared with the distribution after the type A dissection. In addition, analyzing the stress distribution in response to pressurization reveals that before the type A dissection there is a large divergence in the principal stress vectors at the lesser curve but this transitions to a more uniform hoop stress after the type A dissection.

CONCLUSIONS

Our analysis demonstrates that Gaussian surface curvature analysis captures changes in aortic geometry that are otherwise silent in centerline curvature analysis. Here, we show that as the aorta develops a type A dissection it is able to more smoothly handle the hoop stress at the lesser curve compared with the stress focusing seen in the before type A geometry. We propose that the geometric focusing before type A creates a higher energy stress state, which is relaxed on retrograde dissection. Thus, Gaussian curvature analysis may provide a window to capture underlying geometric instability in type B dissections.

Identification of novel splice mutation in SMAD3 in two Cypriot families with nonsyndromic thoracic aortic aneurysm. Two case reports

BACKGROUND

Thoracic aortic aneurysm and dissection (TAA/D) represents a potentially lethal disease group characterized by an increased risk of dissection or rupture. Only a small percentage (approximately 30%) of individuals with nonsyndromic familial TAA/D have a pathogenic variant in one of the genes that have been found to be associated with the disease.

METHODS

A targeted sequencing panel and direct sequencing approach were used to identify causative mutations in the index patients and other family members.

RESULTS

In this study we report two apparently unrelated Cypriot families with nonsyndromic familial TAA/D. The proband A is a female patient diagnosed with TAA/D and intracranial aneurysm and opted for an elective intervention. The proband B is a male patient who was diagnosed with TAA/D and underwent cardiac surgery. Sequencing analysis identified a novel splice site variant (c.871+1G>A) in SMAD3 which is shown to be associated with the disease. Analysis of mRNA from the patient's tissue confirmed aberrant splicing and exon 6 skipping.

CONCLUSION

Our findings expand the mutation spectrum of variants that have been shown to be associated with nonsyndromic familial TAA/D. This study demonstrates the importance of a comprehensive clinical and genetic evaluation aiming at early diagnosis and intervention.

A New Clinically Driven Classification for Acute Aortic Dissection

Objectives: To report a new classification scheme for acute aortic dissection (AAD) that considers the aortic arch as a separate entity and integrates patterns of malperfusion syndrome (MPS). The proposed classification was evaluated retrospectively in a large population.

Materials and Methods: We retrospectively reviewed pre-therapy CT angiograms of 226 consecutive patients (mean ± SD age: 64 ± 12 years) with AAD. AADs were reclassified with a new classification scheme that included three aortic dissection types (A, involving at least the ascending aorta; B, involving exclusively the descending aorta; and C, involving the aortic arch with/without the descending aorta) and four malperfusion grades (0: no MPS; 1: dynamic MPS; 2: static MPS; 3: static and dynamic MPS). AAD features were assessed and correlated to patient outcomes.

Results: According to the new classification, we identified 152 type A dissections (92 A0, 11 A1, 38 A2, 11 A3); 50 type B (38 B0, 5 B1, 6 B2, 1 B3); and 24 type C (17 C0, 6 C2, 1 C3). Type C represented 11% of all AADs. MPS occurred in 39, 24, and 29% in type A, B, and C, respectively. Type C was treated with significantly more endovascular or hybrid interventions (37%) than in types A (3%) and B (20%) (p < 0.001).

Conclusion: The new AAD classification was feasible, and type C was easily identified (“non-A, non-B”). Preliminary findings supported the usefulness of this classification for the decision-making process and subsequent treatments.

Retrospective Comparative Analysis of Computed Tomography Findings of Acute and Chronic Aortic Dissections and Intramural Hematomas

PURPOSE

The objective of this study was to assess the reliability of ancillary imaging findings in distinguishing acute from chronic aortic dissection (AD) and intramural hematoma (IMH) using computed tomography angiography (CTA).

MATERIALS AND METHODS

Two radiologists specializing in cardiothoracic and vascular imaging reviewed paired CTAs of patients with AD or IMH who underwent CTA in the acute (within 24 h of presentation) and chronic settings. The radiologists were blinded to the temporal order of the CTAs. Minimum and maximum flap thicknesses and presence or absence of pleural effusion, pericardial effusion, mediastinal hematoma or fat standing, and mediastinal lymphadenopathy were recorded.

RESULTS

Patients included 25 male individuals and 13 female individuals with a mean age of 59 years (range: 34 to 87 y). The group included 29 AD and 9 IMH cases. The median interval between the paired CTs was 542 days (range: 100 to 2533 d). Respectively, the mean minimum flap thicknesses in the acute and chronic AD were 1.3 and 1.4 mm (P=0.3), and the mean maximum flap thicknesses were 2.7 and 2.9 mm (P=0.29). The incidences of ancillary findings in acute and chronic AD and IMH were as follows: pleural effusion (55% vs. 37%, P=0.143), pericardial effusion (8% vs. 11%, P=1.0), lymphadenopathy (47% vs. 47%, P=1.0), and periaortic fat stranding (87% vs. 76%, P=0.344).

CONCLUSIONS

Ancillary CT imaging findings traditionally ascribed to acute AD and IMH are also often found in the chronic setting and are not reliable indicators of acuity. Flap thickness in AD may not be a reliable imaging indicator of acuity of AD.

Hybrid treatment of type B aortic dissection with retrograde extension in a patient with anomalous aortic arch

Hybrid treatment of aortic arch encompasses a combination of endovascular stenting with surgical revascularization of supraaortic branches. Herein, we report a 53-year-old male case of type B aortic dissection with retrograde extension and anomalous aortic arch. The patient was successfully treated by hybrid treatment using bilateral carotico-subclavian bypass grafting and endovascular stent grafting.

Total Endovascular Treatment of Acute Non-A-non-B Dissection Complicated by Visceral Malperfusion without Primary Entry Tear Coverage

Management of visceral ischemia due to non-A, non-B dissection is extremely challenging due to the position of the primary entry tear at the level of the brachiocephalic vessels. We report on a patient who was admitted for a complicated non-A, non-B-type dissection with visceral and leg ischemia. A covered stent graft was implanted below the primary entry tear to redirect the flow in the true lumen, associated with stents implantation in the visceral arteries, to treat the dissection's static component. The patient did well, without need for bowel resection visceral or late stent restenosis. Stent-graft implantation below the primary entry tear in cases of visceral ischemia due to non-A, non-B dissection seems feasible.

Hybrid aortic repair with antegrade supra-aortic and renovisceral debranching from ascending aorta

Aortic dissection is a life threatening condition. Hybrid repair has been described for the treatment of complex aortic pathology such as thoracoabdominal aortic aneurysms (TAAA) and type A and B dissections, although open and total endovascular repair are also possible. Open surgery is still associated with substantial perioperative morbi-mortality rates, thus less invasive techniques such as endovascular repair and hybrid procedures can achieve good results in centers with experience. We present the case of a patient with a chronic type B dissection and TAAA degeneration that was treated in a single stage hybrid procedure with antegrade supra-aortic and renovisceral debranching from the ascending aorta and TEVAR. At three-year follow up, the patient is free of intervention-related complications.

Clinical features and prognosis of patients with acute aortic dissection in China

Objective To evaluate the clinical features, risk factors, and prognostic significance of different Stanford types of acute aortic dissection (AAD). Methods We retrospectively analyzed the clinical data and prognostic predictors in 105 patients with AAD (37 with Stanford type A and 68 with Stanford type B) at Tianjin Medical University General Hospital and Tianjin 4th Central Hospital from January 2014 to November 2015. Results Patients with Marfan syndrome and bicuspid aortic valve constituted 24.3% and 8.1%, respectively, of patients with type A AAD; these proportions were significantly higher than those of patients with type B AAD (7.4% and 0.0%, respectively). The proportion of iatrogenic causes of type A AAD (8.1%) was significantly higher than that of type B AAD (0.0%). Computed tomography angiography showed that the proportion of involvement of the aortic arch and pericardial effusion (86.5% and 18.9%, respectively) in patients with type A AAD were higher than those in patients with type B AAD (23.5% and 5.9%, respectively). Endovascular treatment was performed in a higher proportion of patients with type B than A AAD (70.6% vs. 5.4%, respectively). Conclusion Systolic blood pressure, pericardial effusion, periaortic hematoma, conservative treatment, and open surgery were independent predictors of increased mortality in patients with AAD.

Carotid Artery Dissection and Ischemic Stroke Originating from Localized Aortic Arch Dissection

Aortic dissection is an infrequent but important cause of acute ischemic stroke (AIS), and must not be overlooked because of a possible worse outcome, especially with the use of an intravenous recombinant tissue plasminogen activator. We report a case of left carotid artery dissection and AIS originating from localized aortic arch dissection, pathologically caused by cystic medial necrosis in the tunica media.

CT of suspected thoracic acute aortic injury in the emergency department: is routine abdominopelvic imaging worth the additional collective radiation dose?

This study aimed to determine the incidence of non-traumatic acute aortic injury (AAI) extending from the chest into the abdomen or pelvis in emergency department (ED) patients with acute aortic syndrome (AAS), to estimate the effective dose of the abdominopelvic portion of these CT exams, and to compare the number needed to screen (NNS) with the collective population radiation dose of imaging those stations. All patients (n = 238) presenting to the ED with AAS between March 2014 and June 2015 who were imaged per CT AAI protocol (noncontrast and contrast-enhanced CT angiography of the chest, abdomen, and pelvis) were retrospectively identified in this IRB-approved HIPAA-compliant study. The Stanford classification for positive cases of AAI was further subclassified based on chest, abdominal, or pelvic involvement. The dose length product (DLP) of each exam was used to estimate the dose of the abdominal and pelvic stations and the collective effective dose for the population. There were five cases of aortic dissection (AD) and two of intramural hematoma (IMH), with an AAI incidence of 2.9/100. Three cases of AAI were confined to the chest. Two cases of AAI were confined to the chest and abdomen, and two cases involved the chest, abdomen, and pelvis. There was only one case of AAI involving the ascending aorta that extended into the abdomen or pelvis. The number needed to screen to identify (a) AAI extending from the chest into the abdomen or pelvis was 59.5 and (b) Stanford A AAI extending into the abdomen or pelvis was 238. The estimated mean effective dose for the abdominopelvic stations were unenhanced abdomen 2.3 mSv, unenhanced pelvis 3.3 mSv, abdominal CTA 2.5 mSv, and pelvic CTA 3.6 mSv. The collective effective doses to the abdomen and pelvis with unenhanced CT and CTA in 59.5 patients and 238 patients were 761.6 and 3046.4 mSv, respectively. While the estimated mean effective dose for imaging of the abdominopelvic stations are low, the collective effective dose should also be considered. It may be beneficial to modify or omit routine unenhanced CT and/or CTA of the abdomen/pelvis in this patient population in the absence of abdominal symptoms, and image the abdomen and pelvis in positive thoracic cases only.

[Pre- and postoperative imaging of type B aortic dissection]

Type B aortic dissections are serious diseases with a 60 to 80 % 5-year survival rate. Although typically managed with a medical treatment, surgery may be necessary in the acute/subacute or the chronic phase if significant complications are encountered. For these patients, CT angiography is the first-line imaging modality, used for indicating and preparing the surgical procedure as well as for follow-up. Physicians in charge of these patients should be familiar with the key reading points. Visceral malperfusion is the most common acute complication, while aneurysmal dilatation of the false lumen is the most common chronic complication, with surgical management generally indicated when the axial diameter of the aorta exceeds 55mm. Endovascular treatment tends to replace open surgery: it requires precise measurements and identification of the entry tear (contribution of 4D-MRA).

Recommendations for accurate CT diagnosis of suspected acute aortic syndrome (AAS)--on behalf of the British Society of Cardiovascular Imaging (BSCI)/British Society of Cardiovascular CT (BSCCT)

Accurate and timely assessment of suspected acute aortic syndrome is crucial in this life-threatening condition. Imaging with CT plays a central role in the diagnosis to allow expedited management. Diagnosis can be made using locally available expertise with optimized scanning parameters, making full use of recent advances in CT technology. Each imaging centre must optimize their protocols to allow accurate diagnosis, to optimize radiation dose and in particular to reduce the risk of false-positive diagnosis that may simulate disease. This document outlines the principles for the acquisition of motion-free imaging of the aorta in this context.

The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome

The term "acute aortic syndrome" (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions.