Descending threshold for ascending aortic aneurysmectomy: Is it time for a “left-shift” in guidelines?

A highly penetrant ACTA2 mutation of thoracic aortic disease

BACKGROUND

The role of ACTA2 mutations in Familial Aortic Disease has been increasingly recognized. We describe a highly penetrant variant (R118Q) in a family with aortic disease.

CASE REPORT

A patient presented to us for elective repair of an ascending aortic aneurysm with a family history of his mother expiring after aortic dissection. Genetic testing revealed he was a heterozygous carrier of the ACTA2 missense mutation R118Q. Subsequently, all living family members were tested for this variant and a full medical history was obtained to compile a family tree for the variant and penetrance of an aortic event (defined as lifetime occurrence of aortic surgery / dissection). In total 9 family members were identified and underwent genetic testing with 7/9 showing presence of the ACTA2 R118Q mutation or an aortic event. All patients over the age of 50 (n = 4) had an aortic event. Those events occurred at ages 54, 55, 60, and 62 (mean event at 57.8 ± 3.9 years). Three family members with the variant under the age of 40 have not had an aortic event and most are undergoing regular aortic surveillance via CT scan.

CONCLUSIONS

Existing studies of known ACTA2 mutations describe a 76% aortic event rate by 85 years old. The R118Q missense mutation is a less common ACTA2 variant, estimated to be found in about 5% of patients with known mutations. Prior studies have predicted the R118Q mutation to have a slightly decreased risk of aortic events compared to other ACTA2 mutations. In this family, however, we demonstrate 100% penetrance of aortic disease above age 50. In today's era of excellent outcomes in elective aortic surgery, our team aggressively offers elective repair. We advocate for strict aortic surveillance for patients with this variant and would consider elective aortic replacement at 4.5 cm, or at an even smaller diameter in patients with a strong family history of dissection who are identified with this mutation.

Fate of the unoperated ascending thoracic aortic aneurysm: three-decade experience from the Aortic Institute at Yale University

AIMS

This study aims to outline the 'true' natural history of ascending thoracic aortic aneurysm (ATAA) based on a cohort of patients not undergoing surgical intervention.

METHODS AND RESULTS

The outcomes, risk factors, and growth rates of 964 unoperated ATAA patients were investigated, over a median follow-up of 7.9 (maximum of 34) years. The primary endpoint was adverse aortic events (AAE), including dissection, rupture, and aortic death. At aortic sizes of 3.5-3.9, 4.0-4.4, 4.5-4.9, 5.0-5.4, 5.5-5.9, and ≥6.0 cm, the average yearly risk of AAE was 0.2%, 0.2%, 0.3%, 1.4%, 2.0%, and 3.5%, respectively (P < 0.001), and the 10-year survival free from AAE was 97.8%, 98.2%, 97.3%, 84.6%, 80.4%, and 70.9%, respectively (P < 0.001). The risk of AAE was relatively flat until 5 cm of aortic size, at which it began to increase rapidly (P for non-linearity <0.001). The mean annual growth rate was estimated to be 0.10 ± 0.01 cm/year. Ascending thoracic aortic aneurysms grew in a very slow manner, and aortic growth over 0.2 cm/year was rarely seen. Multivariable Cox regression identified aortic size [hazard ratio (HR): 1.78, 95% confidence interval (CI): 1.50-2.11, P < 0.001] and age (HR: 1.02, 95% CI: 1.00-1.05, P = 0.015) as significant independent risk factors for AAE. Interestingly, hyperlipidemia (HR: 0.46, 95% CI: 0.23-0.91, P = 0.025) was found to be a significant protective factor for AAE in univariable Cox regression.

CONCLUSION

An aortic size of 5 cm, rather than 5.5 cm, may be a more appropriate intervention criterion for prophylactic ATAA repair. Aortic growth may not be an applicable indicator for intervention.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

A machine learning approach for predicting complications in descending and thoracoabdominal aortic aneurysms

OBJECTIVE

To use machine learning to predict rupture, dissection, and all-cause mortality for patients with descending and thoracoabdominal aortic aneurysms in an effort to improve on diameter-based surgical intervention criteria.

METHODS

Retrospective data from 1083 patients with descending aortic diameters 3.0 cm or greater were collected, with a mean follow-up time of 3.52 years and an average descending diameter of 4.13 cm. Six machine learning classifiers were trained using 44 variables to predict the occurrence of dissection, rupture, or all-cause mortality within 1, 2, or 5 years of initial patient encounter for a total of 54 (6 × 3 × 3) separate classifiers. Classifier performance was measured using area under the receiver operator curve.

RESULTS

Machine learning models achieved area under the receiver operator curves of 0.842 to 0.872 when predicting type B dissection, 0.847 to 0.856 when predicting type B dissection or rupture, and 0.820 to 0.845 when predicting type B dissection, rupture, or all-cause mortality. All models consistently outperformed descending aortic diameter across all end points (area under the receiver operator curve = 0.713-0.733). Feature importance inspection showed that other features beyond aortic diameter, such as a history of myocardial infarction, hypertension, and patient sex, play an important role in improving risk prediction.

CONCLUSIONS

This study provides surgeons with a more accurate, machine learning-based, risk-stratification metric to predict complications for patients with descending aortic aneurysms.

Elective ascending aortic aneurysm repair outcomes in a nationwide US cohort

OBJECTIVE

To quantify contemporary outcomes following elective ascending aortic aneurysm repair, to determine risk factors for adverse events and to evaluate difference by institutional surgical volume.

METHODS

We included all elective hospitalisations of adult patients with an ascending aortic aneurysm who underwent aneurysm repair in the Nationwide Readmissions Database between 2016 and 2019. The primary outcome was a composite of in-hospital mortality, stroke (ischaemic and non-ischaemic) and myocardial infarction (MI). We identified independent predictor of adverse events and investigated outcomes by institutional volume.

RESULTS

Among 12 043 patients (mean 62.8 years of age, 28.0% female), MI, stroke or in-hospital death occurred in 598 (4.9%) patients during the index admission (acute stroke: 2.7%, MI: 0.7%, in-hospital death: 2.0%). The strongest predictors of in-hospital death, stroke or MI were chronic weight loss, pulmonary circulation disorder and concomitant descending aortic surgery. Higher procedural volume was associated with a lower incidence of in-hospital death, stroke or MI (OR comparing the highest with the lowest tertile 0.71, 95% CI 0.57 to 0.87; p=0.001) and in-hospital death (OR 0.51, 95% CI 0.37 to 0.72; p<0.001), but no difference in 30-day readmissions.

CONCLUSIONS

The overall rate of in-hospital death, stroke and MI is nearly 5% in patients undergoing elective ascending aortic aneurysm repair. Among several predictors, chronic weight loss is associated with the largest increase in the risk of poor outcomes. Higher hospital volume is associated with a lower in-hospital mortality, highlighting the importance to refer patients to high-volume centres while discussing the risks and benefits of proceeding with repair.

Ascending Aortic Volume: A Feasible Indicator for Ascending Aortic Aneurysm Elective Surgery?

Diameter-based criterion have been widely adopted for preventive surgery of ascending thoracic aortic aneurysm (ATAA). However, recent and growing evidence has shown that diameter-based methods may not be sufficient for identifying patients who are at risk of an ATAA. In this study, fluid-structure interaction (FSI) analysis was performed on one-hundred ATAA geometries reconstructed from clinical data to examine the relationship between hemodynamic conditions, ascending aortic volume (AAV), ascending aortic curvature, and aortic ratios measured from the reconstructed 3D models. The simulated hemodynamic and biomechanical parameters were compared among different groups of ATAA geometries classified based on AAV. The ATAAs with enlarged AAV showed significantly compromised hemodynamic conditions and higher mechanical wall stress. The maximum oscillatory shear index (OSI), particle residence time (PRT) and wall stress (WS) were significantly higher in enlarged ATAAs compared with controls (0.498 [0.497, 0.499] vs 0.499 [0.498, 0.499], p = 0.002, 312.847 [207.445, 519.391] vs 996.047 [640.644, 1573.140], p < 0.001, 769.680 [668.745, 879.795] vs 1072.000 [873.060, 1280.000] kPa, p < 0.001, respectively). Values were reported as median with interquartile range (IQR). AAV was also found to be more strongly correlated with these parameters compared to maximum diameter. The correlation coefficient between AAV and average WS was as high as 0.92 (p < 0.004), suggesting that AAV might be a feasible risk identifier for ATAAs. STATEMENT OF SIGNIFICANCE: Ascending thoracic aortic aneurysm is associated with the risk of dissection or rupture, creating life-threatening conditions. Current surgical intervention guidelines are purely diameter based. Recently, many studies proposed to incorporate other morphological parameters into the current clinical guidelines to better prevent severe adverse aortic events like rupture or dissection. The purpose of this study is to gain a better understanding of the relationship between morphological parameters and hemodynamic parameters in ascending aortic aneurysms using fluid-solid-interaction analysis on patient-specific geometries. Our results suggest that ascending aortic volume may be a better indicator for surgical intervention as it shows a stronger association with pathogenic hemodynamic conditions.

Postoperative imaging of thoracic aortic repairs

Imaging plays a crucial role in the postoperative monitoring of thoracic aortic repairs. With the development of multiple surgical techniques to repair the ascending aorta and aortic arch, it can be a daunting challenge for the radiologist to diagnose potential pathologies in this sea of various techniques, each with their own normal postoperative appearance and potential complications. In this paper, we will provide a comprehensive review of the postoperative imaging in the setting of thoracic aortic repairs, including the role of imaging, components of thoracic aortic repairs, the normal postoperative appearance, and potential complications.

Prediction of preoperative in-hospital mortality rate in patients with acute aortic dissection by machine learning: a two-centre, retrospective cohort study

OBJECTIVES

To conduct a comprehensive analysis of demographic information, medical history, and blood pressure (BP) and heart rate (HR) variability during hospitalisation so as to establish a predictive model for preoperative in-hospital mortality of patients with acute aortic dissection (AD) by using machine learning techniques.

DESIGN

Retrospective cohort study.

SETTING

Data were collected from the electronic records and the databases of Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine and the First Affiliated Hospital of Anhui Medical University between 2004 and 2018.

PARTICIPANTS

380 inpatients diagnosed with acute AD were included in the study.

PRIMARY OUTCOME

Preoperative in-hospital mortality rate.

RESULTS

A total of 55 patients (14.47%) died in the hospital before surgery. The results of the areas under the receiver operating characteristic curves, decision curve analysis and calibration curves indicated that the eXtreme Gradient Boosting (XGBoost) model had the highest accuracy and robustness. According to the SHapley Additive exPlanations analysis of the XGBoost model, Stanford type A, maximum aortic diameter >5.5 cm, high variability in HR, high variability in diastolic BP and involvement of the aortic arch had the greatest impact on the occurrence of in-hospital deaths before surgery. Moreover, the predictive model can accurately predict the preoperative in-hospital mortality rate at the individual level.

CONCLUSION

In the current study, we successfully constructed machine learning models to predict the preoperative in-hospital mortality of patients with acute AD, which can help identify high-risk patients and optimise the clinical decision-making. Further applications in clinical practice require the validation of these models using a large-sample, prospective database.

TRIAL REGISTRATION NUMBER

ChiCTR1900025818.

Ascending Aorta Dissection Before 5.5 cm Diameter; "It Wasn't Raining When Noah Built the Ark"

INTRODUCTION

The aim of this study was to compare mean maximum ascending aortic diameter at the time of acute aortic dissection with the current surgical threshold for elective ascending aortic operations on non-syndromic thoracic aortic aneurysms.

MATERIAL AND METHODS

All consecutive non-syndromic adult patients admitted for acute type A aortic dissection in a single tertiary centre were prospectively enrolled from April 2020 to March 2021. The primary endpoint was the difference between mean maximum aortic diameter at the time of dissection and the 5.5 cm threshold for elective repair. Secondary endpoints included 30-day/in-hospital mortality, aortic length and comparison with normal controls, length/height ratio index, "actual" preoperative Euroscore II and "predicted" Euroscore II if electively operated.

RESULTS

Among 31 patients ageing 67.3±12.03 years on average, mean maximum aortic diameter at the time of dissection was 5.13±0.66 cm, significantly lower than the guidelines-derived surgical threshold of 5.5 cm (p=0.004). Mean aortic length was 11±1.47 cm, also significantly longer compared normal controls reported in the literature (p<0.001). The 30-day/in-hospital mortality was 35.5%. Mean length/height ratio index was 6.18±0.76 cm/m. Finally, mean "actual" preoperative Euroscore II was 10.43±4.07 which was significantly higher than the 1.47±0.57 "predicted" Euroscore II (p<0.05).

CONCLUSIONS

The maximum aortic diameter at the time of acute type A aortic dissection of non-syndromic cases was significantly lower than the current recommendation for elective repair. Lowering of the current diameter-based surgical threshold of 5.5 cm may be profitable in terms of prevention, but further investigations should be undertaken. Length-based thresholds could also add to timely aortic dissection prevention.

KIF6 Trp719Arg Genetic Variant Increases Risk for Thoracic Aortic Dissection

BACKGROUND

KIF6 (kinesin family member 6), a protein coded by the KIF6 gene, serves an important intracellular function to transport organelles along microtubules. In a pilot study, we found that a common KIF6 Trp719Arg variant increased the propensity of thoracic aortic aneurysms (TAA) to suffer dissection (AD). The present study aims for a definite investigation of the predictive ability of KIF6 719Arg vis à vis AD. Confirmatory findings would enhance natural history prediction in TAA.

METHODS

1108 subjects (899 aneurysm and 209 dissection patients) had KIF6 719Arg variant status determined.

RESULTS

The 719Arg variant in the KIF6 gene correlated strongly with occurrence of AD. Specifically, KIF6 719Arg positivity (homozygous or heterozygous) was substantially more common in dissectors (69.8%) than non-dissectors (58.5%) (p = 0.003). Odds ratios (OR) for suffering aortic dissection ranged from 1.77 to 1.94 for Arg carriers in various dissection categories. These high OR associations were noted for both ascending and descending aneurysms and for homozygous and heterozygous Arg variant patients. The rate of aortic dissection over time was significantly higher for carriers of the Arg allele (p = 0.004). Additionally, Arg allele carriers were more likely to reach the combined endpoint of dissection or death (p = 0.03).

CONCLUSIONS

We demonstrate the marked adverse impact of the 719Arg variant of the KIF6 gene on the likelihood that a TAA patient will suffer aortic dissection. Clinical assessment of the variant status of this molecularly important gene may provide a valuable "non-size" criterion to enhance surgical decision making above and beyond the currently used metric of aortic size (diameter).

Natural history of isolated abdominal aortic dissection: A prospective cohort study

Objectives

Isolated abdominal aortic dissection (IAAD) is extremely rare, with its optimal treatment and intervention timing remaining poorly understood. We aimed to study the natural history of IAAD and facilitate better clinical decision.

Methods

Consecutive patients admitted to our institution from January 2016 to April 2021 were enrolled and followed up prospectively. All-cause death was taken as the primary endpoint.

Results

A total of 68 patients with IAAD were included. The mean age at presentation was 61.2 ± 14.8 (Range: 26.0, 93.0) years and 55 (80.9%) were male. A total of 38 (55.9%) patients were treated conservatively, 27 (39.7%) received endovascular aneurysm repair (EVAR), and 3 (4.4%) underwent open surgery. After a mean follow-up of 2.4 years (Range: 0.1, 5.5), 9 (13.2%) patients died, 8 of whom (21.0%) were treated conservatively and 1 EVAR (3.7%). Compared with EVAR/open surgery, patient treated conservatively had a much worse survival (p = 0.043). There was no significant difference between different IAAD aortic sizes regarding mortality (p = 0.220). Patients with completely thrombosed false lumen fared improved survival rate, followed by partial thrombosis and patency, respectively, although not significantly (p = 0.190). No significant difference was observed between male and female concerning survival rate (p = 0.970). Patients without symptoms had a significantly improved survival (p = 0.048).

Conclusion

On the basis of patients' preference and surgeons' experience, a more aggressive treatment regimen for IAAD should be considered, with EVAR being the first choice, especially for those with persistent symptoms and patent false lumen, regardless of sex, age, or aortic size.

Proximal aortic repair in dialysis patients: A national database analysis

OBJECTIVES

Dialysis is a well-established risk factor for morbidity and mortality after cardiovascular procedures. However, little is known regarding the outcomes of proximal aortic surgery in this high-risk cohort.

METHODS

Perioperative (in-hospital or 30-day mortality) and 10-year outcomes were analyzed for all the patients who underwent open proximal aortic repair with the diagnosis of nonruptured thoracic aortic aneurysm (aneurysm, n = 325) or type A aortic dissection (dissection, n = 461) from 1987 to 2015 using the US Renal Data System database.

RESULTS

In patients with aneurysm, perioperative mortality was 12.6%. The 10-year mortality was 81% ± 3%. Age 65 years or more (hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.03 to 1.78; P = .03), chronic obstructive pulmonary disease (HR, 1.68; 95% CI, 1.01-2.82; P = .047), and Black race (HR, 1.46; 95% CI, 1.09-1.97; P = .01) were independently associated with worse 10-year mortality. In patients with dissection, perioperative mortality was 24.3% and 10-year mortality was 87.9% ± 2.2%. Age 65 years or more (HR, 1.49; 95% CI, 1.19-1.86; P < .001), congestive heart failure (HR, 1.39; 95% CI, 1.11-2.57; P = .004), and diabetes mellitus as the cause of dialysis (HR, 1.75; 95% CI, 1.2-2.57; P = .004) were independently associated with worse 10-year mortality. Black race (HR, 0.74; 95% CI, 0.6-0.92; P = .008) was associated with a better outcome.

CONCLUSIONS

We described challenging perioperative and 10-year outcomes for dialysis patients undergoing proximal aortic repair. The present study suggests the need for careful patient selection in the elective repair of proximal aortic aneurysm for dialysis-dependent patients, whereas it affirms the feasibility of emergency surgery for acute type A aortic dissections.

Knowledge, attitudes, and practice preferences in the surgical threshold for ascending aortic aneurysm among Canadian cardiac surgeons

OBJECTIVE

The survey aimed to assess the practice patterns of Canadian cardiac surgeons on the size threshold at which patients with ascending aortic aneurysm would be offered surgery.

METHODS

A 18-question electronic survey was electronically distributed to 148 practicing cardiac surgeons in Canada via email from January to August 2020. Questions presented clinical scenarios focusing on modifying a single variable, and respondents were asked to identify their surgical size threshold for each of the clinical scenarios.

RESULTS

The individual response rate was 62.0% (91/148) and institutional response rate was 89.3% (25/29). For an incidental asymptomatic ascending aortic aneurysm in a 60-year-old otherwise-healthy male patient with a tricuspid aortic valve and bicuspid aortic valve of 1.9 m², 20.2% of the respondents would recommend surgery when the aneurysm was <5.5 cm. A significant number of surgeons modified their surgical threshold in response to changes to BSA, bicuspid aortic valve, growth rate, age, occupation, symptom, and family history (P < .01). Notably, if the patient had a bicuspid aortic valve, 41.0% of respondents lowered their threshold for surgery, with only 43.0% recommending surgery at ≥5.5 cm (P < .01).

CONCLUSIONS

Practice variations exist in the current size threshold for surgery of ascending aortic aneurysms in Canada. These differences between surgeons are further accentuated in the context of bicuspid aortic valve, smaller body stature, younger age, low growth rate, family history, and for the performance of isometric exercise. These represent important areas where future prospective studies are required to inform best practice.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

High Prevalence of Thoracic Aortic Dilatation in Men with Previous Inguinal Hernia Repair

Background  Identifying a useful marker for thoracic aortic dilatation (TAD) could help improve informed clinical decisions, enhance diagnosis, and develop TAD screening programs. Inguinal hernia could be such a marker. This study tested the hypothesis that the thoracic aorta is larger and more often dilated in men with previous inguinal hernia repair versus nonhernia controls.

Methods  Four hundred men each with either previous inguinal hernia repair or cholecystectomy (controls) were identified to undergo chest computed tomography to measure the diameter of the thoracic aorta in the aortic root, ascending, isthmic, and descending aorta and to provide self-reported health data. Presence of TAD (root or ascending diameter > 45 mm; isthmic or descending diameter > 35 mm) and thoracic aortic diameters were compared between groups and associations explored using uni- and multivariable statistical methods.

Results  Complete data were obtained from 470/718 (65%) eligible participants. TAD prevalence was significantly higher in the inguinal hernia group: 21 (10%) versus 6 (2.4%), p  = 0.001 for proximal TAD, 29 (13%) versus 21 (8.3%), p  = 0.049 for distal TAD, and 50 (23%) versus 27 (11%), p  < 0.001 for all aortic segments combined. In multivariable analysis, previous inguinal hernia repair was independently associated with dilatation of the proximal aorta (odds ratio 5.3, 95% confidence interval 1.8–15, p  = 0.003). Contrarily, mean thoracic aortic diameters were similar (root and ascending aorta) or showed clinically irrelevant differences (isthmus and descending aorta).

Conclusion  TAD, but not increased aortic diameters on average, was common and significantly more prevalent in men with previous inguinal hernia repair. Hernia could be a marker condition associated with increased prevalence of TAD. Ultimately, TAD screening could consider hernia as a possible selection criterion.

Existing and Emerging Approaches to Risk Assessment in Patients with Ascending Thoracic Aortic Dilatation

Ascending thoracic aortic aneurysm is a life-threatening disease, which is difficult to detect prior to the occurrence of a catastrophe. Epidemiology patterns of ascending thoracic aortic dilations/aneurysms remain understudied, whereas the risk assessment of it may be improved. The electronic databases PubMed/Medline 1966–2022, Web of Science 1975–2022, Scopus 1975–2022, and RSCI 1994–2022 were searched. The current guidelines recommend a purely aortic diameter-based assessment of the thoracic aortic aneurysm risk, but over 80% of the ascending aorta dissections occur at a size that is lower than the recommended threshold of 55 mm. Moreover, a 55 mm diameter criterion could exclude a vast majority (up to 99%) of the patients from preventive surgery. The authors review several visualization-based and alternative approaches which are proposed to better predict the risk of dissection in patients with borderline dilated thoracic aorta. The imaging-based assessments of the biomechanical aortic properties, the Young’s elastic modulus, the Windkessel function, compliance, distensibility, wall shear stress, pulse wave velocity, and some other parameters have been proposed to improve the risk assessment in patients with ascending thoracic aortic aneurysm. While the authors do not argue for shifting the diameter threshold to the left, they emphasize the need for more personalized solutions that integrate the imaging data with the patient’s genotypes and phenotypes in this heterogeneous pathology.

Toward standard abbreviations and acronyms for use in articles on aortic disease

Objectives

Academic medical literature is fraught with complex article-specific acronyms and abbreviations that can impair communication and make reading arduous. Our goal is to ease frustration with bespoke, inconsistent, and variable sets of abbreviations that currently exist for common aorta-related terminology (eg, anatomy, imaging, disease, and therapy). We hope to ease reading and improve communication in the aortic sphere of cardiovascular literature.

Methods

We reviewed a total of 205 published references related to aortic disease, including a systematic review of aorta-related articles in the Journal of Thoracic and Cardiovascular Surgery from the years 2020 and 2021. The array of variable definitions, abbreviations, and acronyms encountered in different papers that refer to the same terminology was striking, revealing that there were few standardized abbreviations in the aortic literature. We cataloged these terms, their associated abbreviations, and their frequency of use, and compiled a list of proposed standard abbreviations for commonly used terms that could be implemented uniformly in articles written about aortic diseases.

Results

We present suggested acronyms and abbreviations for common terminology related to the aorta. It is anticipated that this standard list will evolve over time as the literature and technology of the field grows and develops.

Conclusions

A proposed standard set of acronyms and abbreviations for aorta-related terminology is provided that, if found useful, could be implemented broadly in the aortic literature.

Association of dissected ascending aorta diameter with preoperative adverse events in patients with acute type A aortic dissection

BACKGROUND

Acute type A aortic dissection (ATAAD) is a life-threatening disease associated with high morbidity and mortality.

AIM

To evaluate the diameter of dissected ascending aorta in patients diagnosed with ATAAD and whether the aortic diameter is associated with preoperative adverse events.

METHODS

A total of 108 patients diagnosed with ATAAD who underwent emergency operation under hypothermic circulatory arrest were enrolled in this study. Demographic characteristics and perioperative data were recorded. In all patients, preoperative chest and abdomen computed tomography (CT) scans were performed.

RESULTS

Median age of the patients was 61.5 (52.5-70.5) years and median body mass index (BMI) was 28.2 (25.1-32.6) cm². The number of female patients was 37 (25%). Median diameter of the ascending aorta was 5.0 (4.5-6) cm and 53.8% of the patients had an aortic diameter < 5.0 cm, while 32.3% of the patients had an aortic diameter of 4.5cm and 72.0% had an ascending aorta diameter < 5.5 cm. The diameter of the ascending aorta did not differ in patients with vs without preoperative adverse events: Preoperative neurological dysfunction (P = 0.53) and hemodynamic instability (P = 0.43). Median age of patients with preoperative hemodynamic instability was 65 (57.5-74) years, while it was 60 (51-68) years in patients without (P = 0.04)

CONCLUSION

Although current guidelines suggest replacing the ascending aorta with a diameter > 5.5 cm, most of the patients with ATAAD had an aortic diameter of less than 5.5 cm. The diameter of the ascending aorta in patients diagnose with ATAAD is not associated with preoperative adverse events.

Contribution of the innate and adaptive immune systems to aortic dilation in murine mucopolysaccharidosis type I

BACKGROUND

Adult immunocompetent male C57Bl/6 mucopolysaccharidosis, type I (MPSI) mice develop aortic insufficiency (AI), dilated ascending aortas and decreased cardiac function, findings not observed in immune incompetent adult male NSG MPSI mice. We sought to determine why.

METHODS

Cardiac ultrasound measurements of ascending aorta and left ventricular dimensions and Doppler interrogation for AI were performed in 6-month-old male B6 MPSI (N = 12), WT (N = 6), NSG MPSI (N = 8), NSG (N = 6) mice. Urinary glycosaminoglycans, RNA sequencing with quantitative PCR were performed and aortic pathology assessed by routine and immunohistochemical staining on subsets of murine aortas.

RESULTS

Ascending aortic diameters were significantly greater, left ventricular function significantly decreased, and AI significantly more frequent in B6 MPSI mice compared to NSG MPSI mice (p < 0.0001, p = 0.008 and p = 0.02, respectively); NSG and B6 WT mice showed no changes. Urinary glycosaminoglycans were significantly greater in B6 and NSG MPSI mice and both were significantly elevated compared to WT controls (p = 0.003 and p < 0.0001, respectively). By RNA sequencing, all 11 components of the inflammasome pathway were upregulated in B6 MUT, but only Aim2 and Ctsb in NSG MUT mice and none in WT controls. Both B6 and NSG MUT mice demonstrated variably-severe intramural inflammation, vacuolated cells, elastin fragmentation and disarray, and intense glycosaminoglycans on histological staining. B6 MPSI mice demonstrated numerous medial MAC2+ macrophages and adventitial CD3+ T-cells while MAC2+ macrophages were sparse and CD3+ T-cells absent in NSG MPSI mice.

CONCLUSIONS

Aortic dilation, AI and decreased cardiac function occur in immunocompetent B6 MPSI male mice but not in immune incompetent NSG MPSI mice, unrelated to GAG excretion, upregulation of Ctsb, or routine histologic appearance. Upregulation of all components of the inflammasome pathway in B6 MUT, but not NSG MUT mice, and abundant medial MAC2 and adventitial CD3 infiltrates in B6, but not NSG, MPSI aortas differentiated the two strains. These results suggest that the innate and adaptive immune systems play a role in these cardiac findings which may be relevant to human MPSI.

Aortic gene dictionary in the precision medicine era—update from the Aortic Institute at Yale New Haven

This paper reviews the current understanding of the inherited, genetic nature of thoracic aortic aneurysm and dissection (TAAD), as well as the practice of genetic testing for thoracic aortic disease at the Aortic Institute at Yale-New Haven Hospital.

Update on the molecular landscape of thoracic aortic aneurysmal disease

PURPOSE OF THE REVIEW

Thoracic aortic aneurysms and dissections (TAADs) are a major health problem in the Western population. This review summarises recent discoveries in the genetic landscape of TAAD disease, discusses current challenges in clinical practice, and describes the molecular road ahead in TAAD research. Disorders, in which aneurysmal disease is not observed in the thoracic aorta, are not discussed.

RECENT FINDINGS

Current gene discovery studies have pinpointed about 40 genes associated with TAAD risk, accounting for about 30% of the patients. Importantly, novel genes, and their subsequent functional characterisation, have expanded the knowledge on disease-related pathways providing crucial information on key elements in this disease, and it pinpoints new therapeutic targets. Moreover, current molecular evidence also suggests the existence of less monogenic nature of TAAD disease, in which the presentation of a diseased patient is most likely influenced by a multitude of genetic and environmental factors.

SUMMARY CLINICAL PRACTICE/RELEVANCE

Ongoing molecular genetic research continues to expand our understanding on the pathomechanisms underlying TAAD disease in order to improve molecular diagnosis, optimise risk stratification, advance therapeutic strategies and facilitate counselling of TAAD patients and their families.

Proximal aortic repair in asymptomatic patients

Objective

Current guidelines for elective proximal aortic repair are applicable to elective first-time procedures in asymptomatic patients without other primary indications or connective tissue disorders and with specified aortic diameter or growth rate. The objective was to characterize the surgical outcomes in this narrowly defined patient-population.

Methods

Guideline-compliant patients were identified from a recent (2014-2019) single unit consecutive surgical cohort (n = 935) by excluding total arch replacements, redos, acute and symptomatic patients, and genetic syndromes. Remaining patients were included regardless of surgical procedure performed. Early (30-day or in-hospital) and 1-year mortality were primary outcome measures. Major complications (stroke, severe renal or respiratory insufficiency, postcardiotomy shock, deep sternal wound infection, permanent pacemaker, and re-exploration) up to 1 year postoperatively were secondary outcome measures.

Results

In the resulting study population (n = 262), median age was 63 (interquartile range, 52-71) years, and median surgical risk (European System for Cardiac Operative Risk Evaluation II) was 3.2% (2.0%-4.4%). Early mortality was 2 of 262 (0.76%) without additional deaths up to 1-year postoperatively. The occurrence of major complications was low: stroke, 2 (0.76%); renal insufficiency, 2 (0.76%); respiratory insufficiency, 1 (0.38%); postcardiotomy shock, 1 (0.38%); deep sternal wound infection, 0; permanent pacemaker, 3 (1.1%); and re-exploration, 20 (7.6%), all occurring in the immediate (30-day) postoperative period and without additional events up to 1 year postoperatively.

Conclusions

In this recent cohort including the target population referred to by and managed in accordance with current guidelines, mortality and major complications were exceptionally infrequent. Guidelines should adequately weigh risks of conservative management against current surgical outcomes.

Association of NFE2L2 Gene Polymorphisms with Risk and Clinical Characteristics of Acute Type A Aortic Dissection in Han Chinese Population

The present study is aimed at investigating the association of NFE2L2 gene polymorphisms with risk and clinical characteristics of acute type A aortic dissection (AAAD) in a Han Chinese population. Six SNPs (rs1806649, rs13001694, rs2364723, rs35652124, rs6721961, and rs2706110) in NFE2L2 were genotyped using SNaPshot Multiplex Kit in 94 adult patients diagnosed with AAAD at our hospital, and 208 healthy Han Chinese subjects from the 1000 Genomes Project were served as the control group. The CC genotype of rs2364723 (CC versus (GC+GG), OR = 2.069, 95% CI: 1.222-3.502, p = 0.006) and CC genotype of rs35652124 (CC versus (CT+TT), OR = 1.889, 95% CI: 1.112-3.210, p = 0.018) were identified as risk factors for AAAD. Multivariable linear regression analysis revealed that the CC genotype of rs2364723 (β = 5.031, 95% CI: 1.878-8.183, p = 0.002) and CC genotype of rs35652124 (β = 4.751, 95% CI: 1.544-7.958, p = 0.004) were associated with increased maximum ascending aorta diameter of AAAD. Patients carrying rs2364723 CC genotype had a higher incidence of coronary artery involvement (31% vs. 12%, p = 0.027), while patients carrying rs35652124 CC genotype had a higher incidence of brain ischemia (9% vs. 0%, p = 0.045). In conclusion, NFE2L2 gene polymorphisms were correlated with risk and severity of AAAD in Han Chinese population.

Trends and Outcomes of Elective Thoracic Aortic Repair and Acute Thoracic Aortic Syndromes in the United States

BACKGROUND

There is a paucity of data on the contemporary outcomes and trends of elective thoracic aortic aneurysm repair and aneurysm-associated acute aortic syndrome.

METHODS

We queried the National Inpatient Sample (NIS) database years 2012-2016 to identify hospitalizations for elective thoracic aortic aneurysm repair and aneurysm-associated acute aortic syndrome. The main study outcome was in-hospital mortality.

RESULTS

The analysis yielded 24,295 hospitalizations for elective thoracic aortic aneurysm repair and 8875 hospitalizations for aneurysm-associated acute aortic syndrome. The number of hospitalizations for elective aortic repair significantly increased from 4375 in 2012 to 5450 in 2016 (P_trend = .01). The number of hospitalizations for acute aortic syndrome numerically increased from 1545 in 2012 to 2340 in 2016 (P_trend = .10). Overall in-hospital mortality for elective aortic repair was 2.4% with no change over time. In-hospital mortality for acute aortic rupture was 39.4% and for acute aortic dissection was 6.2% with no change over time. Hospitalizations for elective aortic repair had lower incidence of complications compared with those for aneurysm-associated acute aortic syndrome, including cardiogenic shock, cardiac arrest, acute stroke, and shorter length of stay. Factors associated with higher mortality among admissions undergoing elective aortic repair included older age, heart failure, valvular disease, and chronic kidney disease. Older age, coagulopathy, and fluid/ electrolytes disorders were associated with increased mortality among those with acute aortic syndrome.

CONCLUSION

Contemporary elective thoracic aortic aneurysm repair is associated with lower in-hospital mortality and morbidity when compared with a clinical presentation for an aneurysm-associated acute aortic syndrome. This should be taken into account when deciding the timing of elective aortic aneurysm repair and balancing the risks and benefits.

Type A aortic dissection in aneurysms having modelled pre-dissection maximum diameter below 45 mm: should we implement current guidelines to improve the survival benefit of prophylactic surgery?

OBJECTIVES

Current guidelines recommend prophylactic replacement of the ascending aorta at an aneurysmal diameter of >55 mm to prevent acute Type A aortic dissection (TAAD) in non-Marfan patients. Several publications have challenged this threshold, suggesting that surgery should be performed in smaller aneurysms to prevent this devastating disease. We reviewed our experience with measuring aortic size at the time of TAAD to validate the existing recommendation for prophylactic ascending aorta replacement.

METHODS

All patients who had been admitted for TAAD to our emergency department from 2014 to 2019 and underwent ascending aorta replacement were included. Marfan patients were excluded. The maximum diameter of the dissected aorta was measured preoperatively using CT scan. We estimated the aortic diameter at the time of dissection to be 7 mm smaller than the measured maximum diameter of the dissected aorta (modelled pre-dissection diameter).

RESULTS

Overall, 102 patients were included. Of these, 67 were male (65.6%) and 35 were female (34.4%), and the cohort’s mean age was 65 ± 12.1 years. In addition, 66% were treated for arterial hypertension. The mean maximum modelled pre-dissection diameter was 39.6 ± 4.8 mm: 39.1 ± 5.1 mm in men and 40.7 ± 2.8 mm in women (P = 0.1). The cumulative 30-day mortality rate was 19.6% (20/102).

CONCLUSIONS

TAAD occurred at a modelled aortic diameter below 45 mm in 87.7% of our patients. Therefore, the current aortic diameter threshold of 55 mm excludes ∼99% of patients with TAAD from prophylactic replacement of the ascending aorta. The maximum diameter of the ascending aorta warrants reappraisal and this parameter should be a distinct part of a personalized decision-making process that also takes into account age, gender and body surface area to establish the surgical indication for preventive aorta replacement aimed to improve the survival benefit of this procedure.

Elective replacement of the ascending aorta: is the 5.5-cm threshold appropriate? The insidious, small aorta

OBJECTIVES

As thoracic aortic aneurysm disease continues to cause significant morbidity and mortality in the general population, the cardiovascular community continues the search for the golden threshold of elective surgical replacement of the ascending aorta.

METHODS

Thoracic aortic aneurysm is a common disease, classified within the 20 most common causes of death in patients over 65 years old. Once aortic complications like dissection or rupture occur, they can prove fatal. Prophylactic surgical replacement of the ascending aorta remains the mainstay of treatment to prevent these complications. Current American and European guidelines agree that the threshold for the diameter for elective replacement of the ascending aorta in non-syndromic, asymptomatic aneurysmal disease is 5.5 cm. Overall, aortic dissection is related to poor prognosis, thus making early intervention paramount.

RESULTS

There is a critical size above which the risk of dissection or rupture becomes extremely high. However, a significant post-dissection increase in diameter is reported, thus rendering the predissection aortic diameter well below the current threshold for elective surgical replacement of the ascending aorta. Moreover, it is widely reported that the majority of acute aortic dissections would not meet the criteria for prophylactic surgery prior to dissection. Additionally, elective surgical ascending aortic replacement in the current era shows a significantly improved risk-benefit ratio, which justifies a more aggressive approach in the management of aortic aneurysmal disease.

CONCLUSIONS

As a result, there is a lot of discussion in the literature about the requirement of a leftward shifting of the surgical threshold for elective aortic replacement.

Analysis of ascending aortic diameter and long-term prognosis in patients with ascending aortic dissection

OBJECTIVES

This study was designed to review the ascending aortic diameter of patients undergoing surgery for AAD in China and its influence on prognosis.

METHODS

In the period between January 2018 and January 2020, 265 patients eligible for analysis of ascending aorta were included in this study. The maximum diameter of the ascending aorta was assessed using preoperative computed tomography (CT) scan for patients.

RESULTS

The mean diameter of the ascending aorta of the reference population was 48.16 ± 9.37 mm, and the percentage of subjects with an aorta <55 mm was 80.38%. In this study, we found that BMI, hypertension, and bicuspid aortic valve are the main factors affecting the widening of the ascending aorta, and the diameter of the ascending aorta in patients with AAD is negatively correlated with the patient's long-term prognosis. However, there is no significant difference in survival rates among patients with different ascending aortic diameter.

CONCLUSIONS

Ascending aortas with smaller diameter are also prone to dissection, most of which occur at a lower surgical threshold than recommended by current guidelines. Therefore, the diameter of ascending aorta cannot be used as an independent risk factor for high-risk patients with aortic dissection, but it can be used as an important indicator to evaluate the long-term prognosis of patients.

Discrepancies in Measurement of the Thoracic Aorta: JACC Review Topic of the Week

Clinicians often encounter discrepant measurements of the ascending aorta that impede, complicate, and impair appropriate clinical assessment-including key issues of presence or absence of aortic growth, rate of growth, and need for surgical intervention. These discrepancies may arise within a single modality (computed tomography scan, magnetic resonance imaging, or echocardiography) or between modalities. The authors explore the origins and significance of these discrepancies, revealing that some "truth" usually underlies all the discrepant measurements, which individually look at the ascending aorta with different perspectives and dimensional definitions. The authors conclude with a practical "question and answer" section that addresses common specific issues in interpretation and management of patients in the real-world setting.

New indicators for systematic assessment of aortic morphology: a narrative review

In order to prevent the occurrence of aortic adverse events in ascending thoracic aortic aneurysm patients, preventive surgery is the sole option in case of large aneurysm. Identifying high-risk patients timely and accurately requires effective predictive indicators of aortic adverse events and accurate risk stratification thresholds. Absolute diameter measured after a single imaging examination, which has been used as the predictive indicator for decades, has been proved to be ineffective for risk stratification in moderately dilated aorta. Previously, new indicators combining absolute diameters with personalized parameters have been reported to show better predictive power of aortic adverse events than absolute diameters by correcting the effect of these parameters on the diameters. Meanwhile, combining three-dimensional parameters to formulate risk stratification thresholds not only may characterize the aortic risk morphology more precisely, but also predict aortic adverse events more accurately. These new indicators may provide more systematic assessment methods of patients’ risk, formulate more personalized intervention strategies for ascending thoracic aortic aneurysm patients, and also provide a basis for researchers to develop more accurate and effective risk thresholds. We also highlight that the algorithm obtained by combining multiple indicators may be a better choice compared with single indicator, but this still requires the support of more evidence. Due to the particularity of syndromic aortic disease, whether these new indicators can be used for its risk stratification is still uncertain. Therefore, the scope of this manuscript does not include this kind of disease.

Aneurysms and dissections - What is new in the literature of 2019/2020 - a European Society of Vascular Medicine annual review

More than 6,000 publications were found in PubMed concerning aneurysms and dissections, including those Epub ahead of print in 2019, printed in 2020. Among those publications 327 were selected and considered of particular interest.

Acute Type A Aortic Dissection Repair After Hours: Does It Influence Outcomes?

BACKGROUND

Time of day has been associated with adverse outcomes in certain surgical pathologies. Because acute type A aortic dissection typically mandates immediate repair, relatively little attention has been paid to the potential impact of the day-night timing of the operation itself. We sought to determine whether patients with acute dissection treated during typical working hours demonstrated a difference in outcomes compared with those who required surgery after hours.

METHODS

We undertook a comprehensive review of our prospectively collected database from July 2014 to October 2018. A total of 164 consecutive patients underwent primary repair of an acute type A dissection. Based on the procedure start time, patients were divided into 2 groups: working hours (7 am to 4 pm, Monday to Friday; n = 60), and after hours (all other times, including weekends and holidays; n = 104). We propensity-matched 58 pairs of patients and analyzed perioperative data and short-term clinical outcomes.

RESULTS

Thirty-day mortality for all 164 patients was 10.4% (17 deaths), which was not significantly different between the matched groups (working-hours: 8 deaths [13.8%] versus after hours: 4 deaths [6.9%]; P = .36). Perfusion, cross-clamp, and circulatory arrest times did not differ between groups, nor did the types of aortic repairs performed. Postoperative complications were also comparable, including stroke, reoperation for bleeding, and new-onset renal failure requiring dialysis.

CONCLUSIONS

Thirty-day mortality and major morbidity after acute type A dissection repair are independent of when the operation is performed. Expeditious surgical intervention is recommended for all primary acute type A dissection, irrespective of time of day.

Evaluating the diagnostic accuracy of maximal aortic diameter, length and volume for prediction of aortic dissection

OBJECTIVE

Management of thoracic aortic aneurysms (TAAs) comprises regular diameter follow-up until the indication criterion for prophylactic surgery is reached. However, this approach is unable to predict the majority of acute type A aortic dissections (ATAADs). The current study aims to evaluate the diagnostic accuracy of ascending aortic diameter, length and volume for occurrence of ATAAD.

METHODS

This two-centre observational cohort study retrospectively screened 477 consecutive patients who presented with ATAAD between 2009 and 2018. Of those, 25 (5.2%) underwent CT angiography (CTA) within 2 years before dissection onset. Aortic diameter, length and volume of these patients ('pre-ATAAD') were compared with those of TAA controls (n=75). Receiver operating curve analysis was performed to evaluate the predictive accuracy of the three different measurements.

RESULTS

96% of patients with pre-ATAAD did not meet the surgical diameter threshold of 55 mm before dissection onset. Maximal aortic diameters (45 (40-49) mm vs 46 (44-49) mm, p=0.075) and volume (126 (95-157) cm³ vs 124 (102-136) cm³, p=0.909) were comparable between patients with pre-ATAAD and TAA controls. Conversely, ascending aortic length (84±9 mm vs 90±16 mm, p=0.031) was significantly larger in patients with pre-ATAAD. All three parameters had an area under the curve of >0.800. At the 55 mm cut-off point, the maximal diameter yielded a positive predictive value (PPV) of 20%. While maintaining same specificity levels, measurements of aortic volume and length showed superior diagnostic accuracy (PPV 55% and 70%, respectively).

CONCLUSION

Measurements of aortic volume and length have superior diagnostic accuracy compared with the maximal diameter and could improve the timely identification of patients at risk for ATAAD.

Nonsyndromic Thoracic Aortic Aneurysms and Dissections-Is Screening Possible?

Nonsyndromic thoracic aortic aneurysm and dissection (TAAD) account for 95% of all TAAD cases and comprise a subset in which the lack of obvious clinical signs makes diagnosis a challenge. Despite the potentially fatal natural history, timely diagnosis and prophylactic surgical intervention allow restoration of near-normal life expectancy in TAAD patients, underlining the critical importance of screening tests. To date, more than 30 TAAD disease-causing genes have been identified, and over 30% of nonsyndromic TAAD patients have a genetic mutation in 1 or more of these genes. Whole exome sequencing allows routine genetic testing in a clinical setting by screening for all TAAD-related genes, thus facilitating personalized aortic care. Additionally, increased vigilance upon diagnosis of certain TAAD-related diseases ("guilty associates") and the emergence of modern radiologic and novel serologic screening tests will further bolster efforts to detect undiagnosed asymptomatic nonsyndromic TAAD.