Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) Reporting Standards for Type B Aortic Dissections

This Society for Vascular Surgery/Society of Thoracic Surgeons (SVS/STS) document illustrates and defines the overall nomenclature associated with type B aortic dissection. The contents describe a new classification system for practical use and reporting that includes the aortic arch. Chronicity of aortic dissection is also defined along with nomenclature in patients with prior aortic repair and other aortic pathologic processes, such as intramural hematoma and penetrating atherosclerotic ulcer. Complicated vs uncomplicated dissections are clearly defined with a new high-risk grouping that will undoubtedly grow in reporting and controversy. Follow-up criteria are also discussed with nomenclature for false lumen status in addition to measurement criteria and definitions of aortic remodeling. Overall, the document provides a facile framework of language that will allow more granular discussions and reporting of aortic dissection in the future. This Society for Vascular Surgery/Society of Thoracic Surgeons (SVS/STS) document illustrates and defines the overall nomenclature associated with type B aortic dissection. The contents describe a new classification system for practical use and reporting that includes the aortic arch. Chronicity of aortic dissection is also defined along with nomenclature in patients with prior aortic repair and other aortic pathologic processes, such as intramural hematoma and penetrating atherosclerotic ulcer. Complicated vs uncomplicated dissections are clearly defined with a new high-risk grouping that will undoubtedly grow in reporting and controversy. Follow-up criteria are also discussed with nomenclature for false lumen status in addition to measurement criteria and definitions of aortic remodeling. Overall, the document provides a facile framework of language that will allow more granular discussions and reporting of aortic dissection in the future. Dr Bavaria discloses a financial relationship with Medtronic Vascular, W. L. Gore & Associates, and Terumo Aortic; Dr Charlton-Ouw with Medtronic and W. L. Gore & Associates. Dr Bavaria discloses a financial relationship with Medtronic Vascular, W. L. Gore & Associates, and Terumo Aortic; Dr Charlton-Ouw with Medtronic and W. L. Gore & Associates. Acute aortic dissection is the most common emergency affecting the human aorta, with high mortality and morbidity without appropriate and time-sensitive treatment. Based on data from the International Registry of Acute Aortic Dissection (IRAD),1de Beaufort H.W. Trimarchi S. Korach A. Di Eusanio M. Gilon D. Montgomery D.G. et al.Aortic dissection in patients with Marfan syndrome based on the IRAD data.Ann Cardiothorac Surg. 2017; 6: 633-641Crossref PubMed Scopus (44) Google Scholar,2Pape L.A. Awais M. Woznicki E.M. Suzuki T. Trimarchi S. Evangelista A. et al.Presentation, diagnosis, and outcomes of acute aortic dissection: 17-year trends from the International Registry of Acute Aortic Dissection.J Am Coll Cardiol. 2015; 66: 350-358Crossref PubMed Scopus (585) Google Scholar patients with acute type B dissection composed approximately 33% of all dissection patients enrolled in the registry across a 17-year period. Management of acute type B dissection has evolved over time and now includes medical, surgical, and endovascular therapies performed by several specialties, including vascular surgery, cardiothoracic surgery, interventional radiology, and cardiology. With the recent blanket U.S. Food and Drug Administration (FDA) approval of endovascular stent grafting for type B aortic dissection (TBAD) as well as our maturing understanding of the anatomy and pathophysiology of the disease, there has been an explosion of literature in multiple specialty journals regarding TBAD presentation, treatment, and outcomes. As such, the purpose of this document is to provide structure to the reporting of TBAD, with particular attention to those attributes of TBAD that, based on the best available evidence to date, would appear to have an impact on outcomes. Prior reporting standards from the Society for Vascular Surgery (SVS) have addressed thoracic endovascular aortic repair (TEVAR) in a more general sense,3Fillinger M.F. Greenberg R.K. McKinsey J.F. Chaikof E.L. Society for Vascular Surgery Ad Hoc Committee on TEVAR Reporting StandardsReporting standards for thoracic endovascular aortic repair (TEVAR).J Vasc Surg. 2010; 52 (1033.e15): 1022-1033Abstract Full Text Full Text PDF PubMed Scopus (454) Google Scholar although these earlier standards did not specifically address aortic dissection. Given the complexity of the topic, it is believed to warrant a separate publication. This combined effort by the SVS and the Society of Thoracic Surgeons (STS) provides a unified consensus on reporting, nomenclature, and classification of TBAD at this point in time. The committee was headed by two co-chairs, one each from the SVS and STS, with each co-chair responsible for a group of six writers evenly balanced between the societies. Each group was then further broken down into three dyads (one SVS and one STS) who were assigned a specific section of the document, the content of which was further refined by the co-chairs. The completed draft document was then approved by all members of the Writing Committee. The document was subsequently reviewed by the SVS and STS document committees and the FDA, and it was available for societal public comments. The final document was approved by the SVS and STS document oversight committees after final editing by the Writing Committee’s co-chairs based on the feedback received in the review process. Classification systems for thoracic aortic dissection allow caregivers to communicate accurately when describing aortic disease and are critical for triage, treatment, and prognostic purposes. Historically, classification systems relied on the anatomic location of intimal entry tears and longitudinal extent of the dissection flap. The original DeBakey classification, first described in 1965, defines aortic dissection according to anatomic features. The more widely adopted Stanford classification simplified the earlier DeBakey classification and is based on whether the ascending aorta is affected. In type A, the ascending aorta is involved; whereas in type B, the ascending aorta is spared, with the entry tear distal to the left subclavian artery (Figure 1). Unlike the DeBakey classification scheme, the Stanford classification does not characterize the distal extent of dissection.4Daily P.O. Trueblood H.W. Stinson E.B. Wuerflein R.D. Shumway N.E. Management of acute aortic dissections.Ann Thorac Surg. 1970; 10: 237-247Abstract Full Text PDF PubMed Scopus (847) Google Scholar Importantly, neither classification scheme addresses aortic dissections that originate in the arch. In arch dissections, the dissection flap or intramural hematoma (IMH) typically involves the transverse arch and often spares the proximal ascending aorta (Figure 2). The entry tear may originate in the arch itself or distal to the left subclavian artery and extend retrograde to the level of the innominate artery or even the distal ascending aorta. Often, the dissection extends into the great vessels themselves. A recent query of IRAD for all patients presenting with acute type B dissection with an identifiable primary intimal tear found evidence for retrograde arch extension in 16.5%. This finding did not appear to have an impact on management strategy or early and late death, suggesting that retrograde arch extension may be analogous to TBAD.5Nauta F.J. Tolenaar J.L. Patel H.J. Appoo J.J. Tsai T.T. Desai N.D. et al.Impact of retrograde arch extension in acute type B aortic dissection on management and outcomes.Ann Thorac Surg. 2016; 102: 2036-2043Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar However, without a standardized method of classifying aortic arch dissections, reporting of outcomes in these patients remains cumbersome and haphazard. Given these limitations, the Writing Committee thought a new classification system relevant to current treatment paradigms was necessary to more precisely describe aortic arch involvement in aortic dissection. Within the new SVS/STS classification scheme for aortic dissection, the distinction between type A and type B is predicated on entry tear location alone. In a type A dissection, the entry tear originates only in zone 0 (Figure 3). The distal extent of a type A aortic dissection is then simply designated by zone. For example, a type A9 dissection represents a dissection entry tear in zone 0 with distal extension of the dissection into zone 9 (Figure 4). Type B dissections include any aortic dissection with an entry tear originating in zone 1 or beyond. Type B dissections are further characterized by two subscripts (BP,D); subscript p describes the proximal zone of involved aorta, and subscript d describes the distal zone of involved aorta. Involved aorta includes both patent and thrombosed false lumen as well as IMH. For example, B1,9 denotes a type B dissection with proximal involvement of zone 1 and distal extension to the level of zone 9 (Figure 5), although the primary entry tear may be anywhere between zones 1 and 9. TBAD may also involve the ascending aorta, designated B0,D in that the primary entry tear originated in zone 1 or beyond yet extended proximally to zone 0 (Figure 6). If the entry tear origin is not identifiable, the dissection will remain indeterminate with the designation I. These dissections will always involve zone 0 or otherwise would be sensibly designated type B. Indeterminate dissections will follow the same format for distal extent as type A. Therefore, an indeterminate dissection extending from zone 0 to zone 9 would be designated I9 until further imaging or gross anatomic findings at surgery identify the origin of the primary entry tear; thus, the I designation may be impermanent. I dissections that are subsequently determined to be type B (ie, primary entry tear in zone 1 or beyond) may require a different treatment algorithm and may have a natural history that differs from true type A dissection. As such, the Writing Committee thought a separate I classification would allow more precise description of dissection type for future research reporting of outcomes for aortic dissection involving zone 0 with differing entry tear origins.Figure 4An aortic dissection with an entry tear in zone 0 is classified as type A. In the example illustrated, the dissection process extends distally to zone 9, such that the dissection is fully classified as A9.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 5An aortic dissection with an entry tear in zone 1 or beyond is classified as type B. In the example illustrated, the entry tear is in zone 3 and the dissection process involves zone 1 proximally and extends distally to zone 9; the dissection is fully classified as B1,9.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 6Example of an aortic dissection with an entry tear in zone 2, which classifies it as type B. The dissection process involves zone 0 proximally and extends distally to zone 9. This dissection is fully classified as B0,9.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Using this new SVS/STS classification system will allow clinicians to conceptually project a precise image of entry tear location and proximal and distal dissection extent with one simple designation (Figure 7). It is not necessarily the intent of the Writing Committee that the new classification system should completely replace the current Stanford and DeBakey systems for everyday clinical use, especially for practitioners who are not subject matter experts in aortic disease. This classification system is intended for research reporting, such as comparative effectiveness studies, where it will allow more granular description of study populations and disease processes particularly relating to arch involvement. Classification of new aortic dissection after prior dissection with or without repair (ie, acute-on-chronic dissection) can be difficult. Patients with a history of prior type A or type B dissection (repaired or unrepaired) now presenting with a new acute dissection should be reported both to historic dissection pathology, type of prior repair (if any), and current “residual” anatomy. For example, patients who present with new acute disease in a medically managed chronic state may be classified as acute-on-chronic AD or BP,D. Similarly, patients with prior aortic surgery managed in the chronic phase and now presenting with acute disease would be described as residual acute-on-chronic AD or BP,D. Central repair of type A dissection, for instance, can carry multiple surgical solutions, such as aortic valve resuspension with supracoronary ascending tube graft; aortic root replacement (eg, Bentall, valve sparing), with or without concomitant hemiarch or total arch replacement; and total arch replacement, also potentially including conventional or frozen elephant trunk repair. Residual arch and descending aortic disease after central aortic repair (ie, remaining type B after type A repair) is the subject of ongoing investigation.6Pan X.D. Li B. Ma W.G. Zheng J. Liu Y.M. Zhu J.M. et al.Endovascular repair of residual intimal tear or distal new entry after frozen elephant trunk for type A aortic dissection.J Thorac Dis. 2017; 9: 529-536Crossref PubMed Scopus (18) Google Scholar Open reconstruction, endovascular repair, and hybrid procedures should therefore describe zones of residual disease with defined proximal and distal anastomoses and landing zones. For instance, a patient with a prior type A proximal aortic repair now presenting with a symptomatic chronic arch and descending thoracic dissection extending to the iliacs may be referred to as a residual B1,11. Classifying this as a residual dissection infers the fact that this patient has undergone prior surgery. We anticipate a significant amount of reporting for management of these situations in the future. In addition to aortic dissection, two other distinct yet related acute aortic diseases require further description with respect to proper reporting: IMH and penetrating atherosclerotic ulcer (PAU). Aortic dissection is defined by the presence of a tear in the intima that results in a separation of the layers of the media and allows blood to flow through the false lumen (Figure 8). This separate, or false, lumen for blood flow is externally bound only by the outer third of the media and adventitia. IMH, in contrast, lacks an identifiable direct communication between the true and false lumens, a condition that authors in Asia have described as “closed thrombosed false lumen.”7Kitai T. Kaji S. Yamamuro A. Tani T. Kinoshita M. Ehara N. et al.Impact of new development of ulcer-like projection on clinical outcomes in patients with type B aortic dissection with closed and thrombosed false lumen.Circulation. 2010; 122: S74-S80Crossref PubMed Scopus (88) Google Scholar It is characterized by a hyperdense, crescent-shaped hemorrhage within the aortic wall best seen on noncontrast-enhanced computed tomography (CT) imaging (Figure 9).8Husainy M.A. Sayyed F. Puppala S. Acute aortic syndrome—pitfalls on gated and non-gated CT scan.Emerg Radiol. 2016; 23: 397-403Crossref PubMed Scopus (9) Google Scholar Several mechanisms for IMH have been proposed, including spontaneous rupture of the vasa vasorum, which causes bleeding and hematoma formation within the aortic wall (Figure 10).9Sundt T.M. Intramural hematoma and penetrating atherosclerotic ulcer of the aorta.Ann Thorac Surg. 2007; 83 ([discussion: S846-50]): S835-S841Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar Others have suggested microscopic tears in the intima as the potential cause.8Husainy M.A. Sayyed F. Puppala S. Acute aortic syndrome—pitfalls on gated and non-gated CT scan.Emerg Radiol. 2016; 23: 397-403Crossref PubMed Scopus (9) Google Scholar,9Sundt T.M. Intramural hematoma and penetrating atherosclerotic ulcer of the aorta.Ann Thorac Surg. 2007; 83 ([discussion: S846-50]): S835-S841Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar Differentiating aortic dissection and IMH can be challenging, and the two conditions may coexist in the same patient. IMH can also progress to frank aortic dissection.Figure 9Noncontrast-enhanced computed tomography (CT) scan demonstrating intramural hematoma (IMH) of the descending thoracic aorta. Note that the IMH appears bright on nonenhanced imaging.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 10Example of the gross pathologic appearance of an intramural hematoma (IMH), in this case of the ascending aorta, as seen during central repair for acute type A IMH.View Large Image Figure ViewerDownload Hi-res image Download (PPT) PAU is defined as an atherosclerotic lesion that penetrates the internal elastic lamina of the aortic wall and is often diagnosed in the presence of an IMH. PAUs are also referred to as ulcer-like projections, especially in Asia7Kitai T. Kaji S. Yamamuro A. Tani T. Kinoshita M. Ehara N. et al.Impact of new development of ulcer-like projection on clinical outcomes in patients with type B aortic dissection with closed and thrombosed false lumen.Circulation. 2010; 122: S74-S80Crossref PubMed Scopus (88) Google Scholar (Figure 11A). Approximately 20% of PAUs have no associated IMH, presumably because of medial fibrosis from chronic atherosclerotic disease.9Sundt T.M. Intramural hematoma and penetrating atherosclerotic ulcer of the aorta.Ann Thorac Surg. 2007; 83 ([discussion: S846-50]): S835-S841Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar,10Cho K.R. Stanson A.W. Potter D.D. Cherry K.J. Schaff H.V. Sundt 3rd, T.M. Penetrating atherosclerotic ulcer of the descending thoracic aorta and arch.J Thorac Cardiovasc Surg. 2004; 127 ([discussion: 1399-401]): 1393-1399Abstract Full Text Full Text PDF PubMed Scopus (186) Google Scholar PAU rupture risk is directly related to ulcer depth. However, PAU with IMH (Figure 11B) has a higher risk of aortic rupture and portends a worse clinical course compared with a similar sized PAU without IMH.11Ganaha F. Miller D.C. Sugimoto K. Do Y.S. Minamiguchi H. Saito H. et al.Prognosis of aortic intramural hematoma with and without penetrating atherosclerotic ulcer: a clinical and radiological analysis.Circulation. 2002; 106: 342-348Crossref PubMed Scopus (405) Google Scholar,12Evangelista A. Czerny M. Nienaber C. Schepens M. Rousseau H. Cao P. et al.Interdisciplinary expert consensus on management of type B intramural haematoma and penetrating aortic ulcer.Eur J Cardiothorac Surg. 2015; 47: 209-217Crossref PubMed Scopus (103) Google Scholar It is important to distinguish between true aortic dissection and IMH in reporting as treatment algorithms and outcomes may differ significantly. The extent of IMH should be reported according to zone, as with aortic dissection, and reporting should include the maximal thickness of the aorta in the zone of IMH. PAU is best characterized by ulcer dimensions (saccular depth and diameter of aortic origin) and location by zone. When pathologic processes coexist with one another, we suggest using the predominant disease for classification purposes. Patients with multiple PAUs should be subscripted with their zone locations (eg, for PAU involving zones 3 and 5, PAU3,5). If concomitant IMH is present, one would add subscripted proximal and distal extent, IMHP,D, as described before. Thus, for a patient with IMH extending from zones 2 to 9 presenting with concomitant PAU in zones 3 and 5, it would be described as IMH2,9 with PAU3,5. The historical chronicity classification of aortic dissection originated from the investigations of Hirst and colleagues,13Hirst Jr., A.E. Johns Jr., V.J. Kime Jr., S.W. Dissecting aneurysm of the aorta: a review of 505 cases.Medicine (Baltimore). 1958; 37: 217-279Crossref PubMed Scopus (1127) Google Scholar who observed that mortality in patients with type A and type B aortic dissection significantly decreased after 14 days. Using this time point, the authors defined acute aortic dissection as ≤14 days from symptom onset and chronic aortic dissection as >14 days from symptom onset. Since this original report, there have been significant advancements in diagnostic imaging, medical treatment, and endovascular and surgical therapy and an improved understanding of the pathophysiologic mechanism of aortic dissection. Therefore, a reappraisal of this classification system is warranted. A key motivation to re-evaluate the chronicity classification system is the application of endovascular therapy to TBAD. TEVAR was initially described in the treatment of TBAD in 1999 and has transformed the management of this disease during the past 20 years.14Dake M.D. Kato N. Mitchell R.S. Semba C.P. Razavi M.K. Shimono T. et al.Endovascular stent-graft placement for the treatment of acute aortic dissection.N Engl J Med. 1999; 340: 1546-1552Crossref PubMed Scopus (1107) Google Scholar TEVAR, along with high-resolution CT scans and intravascular ultrasound, has afforded a more sophisticated understanding of dissection flap properties with respect to the chronicity of the dissection. In the acute phase, the dissection flap is thin and highly compliant, with a curvilinear appearance on CT scan. As the dissection flap ages, it becomes thicker and less compliant and has a straightened appearance on CT (Figure 12).15Peterss S. Mansour A.M. Ross J.A. Vaitkeviciute I. Charilaou P. Dumfarth J. et al.Changing pathology of the thoracic aorta from acute to chronic dissection: literature review and insights.J Am Coll Cardiol. 2016; 68: 1054-1065Crossref PubMed Scopus (81) Google Scholar This enhanced understanding of dissection flap pathophysiology has implications for the classification of the chronicity of TBAD, and therefore any classification system should incorporate these more recent observations pertaining to intimal flap remodeling. These lessons learned from contemporary reports in the endovascular era have prompted a reassessment of the traditional chronicity classification system. In a study similar to the initial work of Hirst, Booher and colleagues16Booher A.M. Isselbacher E.M. Nienaber C.A. Trimarchi S. Evangelista A. Montgomery D.G. et al.The IRAD classification system for characterizing survival after aortic dissection.Am J Med. 2013; 126: 730.e19-730.e24Abstract Full Text Full Text PDF PubMed Scopus (171) Google Scholar examined mortality from the time of symptom onset in 1800 patients (TBAD n = 655) from the IRAD database. In this cohort, Kaplan-Meier survival curves demonstrated distinct strata of mortality risk that varied by chronicity following presentation with aortic dissection. In addition, several studies examining various aortic remodeling outcomes in patients with TBAD treated with TEVAR at different time points have suggested the establishment of an additional subacute classification.17Nienaber C.A. Kische S. Rousseau H. Eggebrecht H. Rehders T.C. Kundt G. et al.Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial.Circ Cardiovasc Interv. 2013; 6: 407-416Crossref PubMed Scopus (678) Google Scholar,18Rodriguez J.A. Olsen D.M. Lucas L. Wheatley G. Ramaiah V. Diethrich E.B. Aortic remodeling after endografting of thoracoabdominal aortic dissection.J Vasc Surg. 2008; 47: 1188-1194Abstract Full Text Full Text PDF PubMed Scopus (114) Google Scholar The subacute phase of TBAD was defined as 15 to 30 days by an SVS report on early outcomes after TEVAR for complicated TBAD.19White R.A. Miller D.C. Criado F.J. Dake M.D. Diethrich E.B. Greenberg R.K. et al.Report on the results of thoracic endovascular aortic repair for acute, complicated, type B aortic dissection at 30 days and 1 year from a multidisciplinary subcommittee of the Society for Vascular Surgery Outcomes Committee.J Vasc Surg. 2011; 53: 1082-1090Abstract Full Text Full Text PDF PubMed Scopus (130) Google Scholar However, the most recent European Society of Cardiology guidelines on the diagnosis and treatment of aortic disease defined the subacute phase as 15 to 90 days.20Erbel R. Aboyans V. Boileau C. Bossone E. Bartolomeo R.D. Eggebrecht H. et al.2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC).Eur Heart J. 2014; 35: 2873-2926Crossref PubMed Scopus (2737) Google Scholar In a study analyzing patients who underwent TEVAR within 3 months of the time of dissection, there was no significant difference in remodeling results of the thoracic aorta between those patients treated at <14 days and those treated between 15 and 90 days.21Lombardi J.V. Cambria R.P. Nienaber C.A. Chiesa R. Mossop P. Haulon S. et al.Aortic remodeling after endovascular treatment of complicated type B aortic dissection with the use of a composite device design.J Vasc Surg. 2014; 59: 1544-1554Abstract Full Text Full Text PDF PubMed Scopus (113) Google Scholar The cumulative data from these reports has led the Writing Committee to develop the following classification system of dissection chronicity, which incorporates both the IRAD and European Society of Cardiology findings: hyperacute, <24 hours; acute, 1 to 14 days; subacute, 15 to 90 days; and chronic, >90 days (Table 1).Table 1Society for Vascular Surgery/Society of Thoracic Surgeons (SVS/STS) Chronicity Classification of Aortic DissectionChronicityTime From Onset of SymptomsHyperacute<24 hoursAcute1-14 daysSubacute15-90 daysChronic>90 days Open table in a new tab Various causes and risk factors for acute TBAD have been noted in the literature, several of which influence decision-making and affect short- and long-term morbidity and mortality. Included here are the more common causes reported in studies on acute TBAD, the incidence of which among the study population should be described in any reports on TBAD. Hypertension was present in 80.9% of patients who presented with acute TBAD in the IRAD database.2Pape L.A. Awais M. Woznicki E.M. Suzuki T. Trimarchi S. Evangelista A. et al.Presentation, diagnosis, and outcomes of acute aortic dissection: 17-year trends from the International Registry of Acute Aortic Dissection.J Am Coll Cardiol. 2015; 66: 350-358Crossref PubMed Scopus (585) Google Scholar In previous reports summarizing the experience at a tertiary care center, 71% of patients with acute dissection were noted to have a history of hypertension,22Lauterbach S.R. Cambria R.P. Brewster D.C. Gertler J.P. Lamuraglia G.M. Isselbacher E.M. et al.Contemporary management of aortic branch compromise resulting from acute aortic dissection.J Vasc Surg. 2001; 33: 1185-1192Abstract Full Text PDF PubMed Scopus (157) Google Scholar whereas in more contemporary reports, 62% of patients with acute TBAD were taking antihypertensive medications at presentation.23Schwartz S.I. Durham C. Clouse W.D. Patel V.I. Lancaster R.T. Cambria R.P. et al.Predictors of late aortic intervention in patients with medically treated type B aortic dissection.J Vasc Surg. 2018; 67: 78-84Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar However, the use of antihypertensive medications as a surrogate for the diagnosis of hypertension is almost certain to underestimate the true incidence of this risk factor in the TBAD population, given that TBAD is often a disease of the socioeconomically disadvantaged who are less likely to comply with risk factor modification.24Andersen N.D. Brennan J.M. Zhao Y. Williams J.B. Williams M.L. Smith P.K. et al.Insurance status is associated with acuity of presentation and outcomes for thoracic aortic operations.Circ Cardiovasc Qual Outcomes. 2014; 7: 398-406Crossref PubMed Scopus (17) Google Scholar Patients who are reported as having hypertension should meet the definition according to the 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults,25Whelton P.K. Carey R.M. Aronow W.S. Casey Jr., D.E. Collins K.J. Dennison Himmelfarb C. et al.2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.J Am Coll Cardiol. 2018; 71: e127-e248Crossref PubMed Scopus (2587) Google Scholar which categorizes hypertension into two stages. Stage 1 is defined as systolic blood pressure of 130 to 139 mm Hg or diastolic blood pressure of 80 to 89 mm Hg. Stage 2 is defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg. Genetically triggered aortic