Unveiling cellular and molecular aspects of ascending thoracic aortic aneurysms and dissections.

Ascending thoracic aortic aneurysm (ATAA) remains a significant medical concern, with its asymptomatic nature posing diagnostic and monitoring challenges, thereby increasing the risk of aortic wall dissection and rupture. Current management of aortic repair relies on an aortic diameter threshold. However, this approach underestimates the complexity of aortic wall disease due to important knowledge gaps in understanding its underlying pathologic mechanisms.Since traditional risk factors cannot explain the initiation and progression of ATAA leading to dissection, local vascular factors such as extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) might harbor targets for early diagnosis and intervention. Derived from diverse embryonic lineages, VSMCs exhibit varied responses to genetic abnormalities that regulate their contractility. The transition of VSMCs into different phenotypes is an adaptive response to stress stimuli such as hemodynamic changes resulting from cardiovascular disease, aging, lifestyle, and genetic predisposition. Upon longer exposure to stress stimuli, VSMC phenotypic switching can instigate pathologic remodeling that contributes to the pathogenesis of ATAA.This review aims to illuminate the current understanding of cellular and molecular characteristics associated with ATAA and dissection, emphasizing the need for a more nuanced comprehension of the impaired ECM-VSMC network.

Four-dimensional flow cardiovascular magnetic resonance aortic cross-sectional pressure changes and their associations with flow patterns in health and ascending thoracic aortic aneurysm.

BACKGROUND: Ascending thoracic aortic aneurysm (ATAA) is a silent and threatening dilation of the ascending aorta (AscAo). Maximal aortic diameter which is currently used for ATAA patients management and surgery planning has been shown to inadequately characterize risk of dissection in a large proportion of patients. Our aim was to propose a comprehensive quantitative evaluation of aortic morphology and pressure-flow-wall associations from four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) data in healthy aging and in patients with ATAA. METHODS: We studied 17 ATAA patients (64.7 ± 14.3 years, 5 females) along with 17 age- and sex-matched healthy controls (59.7 ± 13.3 years, 5 females) and 13 younger healthy subjects (33.5 ± 11.1 years, 4 females). All subjects underwent a CMR exam, including 4D flow and three-dimensional anatomical images of the aorta. This latter dataset was used for aortic morphology measurements, including AscAo maximal diameter (iDMAX) and volume, indexed to body surface area. 4D flow MRI data were used to estimate 1) cross-sectional local AscAo spatial (∆PS) and temporal (∆PT) pressure changes as well as the distance (∆DPS) and time duration (∆TPT) between local pressure peaks, 2) AscAo maximal wall shear stress (WSSMAX) at peak systole, and 3) AscAo flow vorticity amplitude (VMAX), duration (VFWHM), and eccentricity (VECC). RESULTS: Consistency of flow and pressure indices was demonstrated through their significant associations with AscAo iDMAX (WSSMAX:r = -0.49, p < 0.001; VECC:r = -0.29, p = 0.045; VFWHM:r = 0.48, p < 0.001; ∆DPS:r = 0.37, p = 0.010; ∆TPT:r = -0.52, p < 0.001) and indexed volume (WSSMAX:r = -0.63, VECC:r = -0.51, VFWHM:r = 0.53, ∆DPS:r = 0.54, ∆TPT:r = -0.63, p < 0.001 for all). Intra-AscAo cross-sectional pressure difference, ∆PS, was significantly and positively associated with both VMAX (r = 0.55, p = 0.002) and WSSMAX (r = 0.59, p < 0.001) in the 30 healthy subjects (48.3 ± 18.0 years). Associations remained significant after adjustment for iDMAX, age, and systolic blood pressure. Superimposition of ATAA patients to normal aging trends between ∆PS and WSSMAX as well as VMAX allowed identifying patients with substantially high pressure differences concomitant with AscAo dilation. CONCLUSION: Local variations in pressures within ascending aortic cross-sections derived from 4D flow MRI were associated with flow changes, as quantified by vorticity, and with stress exerted by blood on the aortic wall, as quantified by wall shear stress. Such flow-wall and pressure interactions might help for the identification of at-risk patients.

Variants of Focal Adhesion Scaffold Genes Cause Thoracic Aortic Aneurysm.

RATIONALE: Thoracic aortic aneurysm (TAA) leads to substantial mortality worldwide. Familial and syndromic TAAs are highly correlated with genetics. However, the incidence of sporadic isolated TAA (iTAA) is much higher, and the genetic contribution is not yet clear. OBJECTIVE: Here, we examined the genetic characteristics of sporadic iTAA. METHODS AND RESULTS: We performed a genetic screen of 551 sporadic iTAA cases and 1071 controls via whole-exome sequencing. The prevalence of pathogenic mutations in known causal genes was 5.08% in the iTAA cohort. We selected 100 novel candidate genes using a strict strategy, and the suspected functional variants of these genes were significantly enriched in cases compared with controls and carried by 60.43% of patients. We found more severe phenotypes and a lower proportion of hypertension in cases with pathogenic mutations or suspected functional variants. Among the candidate genes, Testin (TES), which encodes a focal adhesion scaffold protein, was identified as a potential TAA causal gene, accounting for 4 patients with 2 missense variants in the LIM1 domain (c.751T>C encoding p.Y251H; c.838T>C encoding p.Y280H) and highly expressed in the aorta. The 2 variants led to a decrease in TES expression. The thoracic aorta was spontaneously dilated in the TesY249H knock-in and Tes-/- mice. Mechanistically, the p.Y249H variant or knockdown of TES led to the repression of vascular smooth muscle cell contraction genes and disturbed the vascular smooth muscle cell contractile phenotype. Interestingly, suspected functional variants of other focal adhesion scaffold genes, including TLN1 (Talin-1) and ZYX (zyxin), were also significantly enriched in patients with iTAA; moreover, their knockdown resulted in decreased contractility of vascular smooth muscle cells. CONCLUSIONS: For the first time, this study revealed the genetic landscape across iTAA and showed that the focal adhesion scaffold genes are critical in the pathogenesis of iTAA.

Authentication of In Situ Measurements for Thoracic Aortic Aneurysms in Mice.

[Figure: see text].

Effect of Anastomosis Angles on Retrograde Perfusion and Hemodynamics of Hybrid Treatment for Thoracoabdominal Aortic Aneurysm.

BACKGROUND: Hemodynamic effects on the retrograde visceral reconstruction (RVR) for thoracoabdominal aortic aneurysms treatment by anastomotic angle remains unclear. This study aims to qualitatively and quantitatively investigate the effects of different anastomotic angles on hemodynamics and patency. METHODS: Three RVR models with 45°, 60° and 90° anastomotic angles were reconstructed respectively by manipulating apostoperative patient-specific model. The manipulated models of the RVRs were numerically simulated and analyzed in terms of hemodynamics including theinstant and cumulative patency, flow pattern and indicators based on wall shear stress (WSS). RESULTS: Although a smaller anastomotic angle may decrease the patency rate of common iliac arteries, it can improve the visceral perfusion during a cardiac cycle. More importantly, RVR with the smallest anastomotic angle experienced a minimal low time-averaged wall shear stress, high oscillatory shear index and relative residence time in the anastomosis region, whereas the largest anastomotic angle can introduce more unfavorable WSS in the graft trunk. Furthermore, a spiral flow pattern was observed in the proximal graft trunk of all three models, where no high-risk shear distribution was detected in this region. CONCLUSION: A smaller anastomotic angle may have more benefits of hemodynamic environment in RVR, especially the WSS distribution and flow pattern in the graft trunk. We may also suggest that additional stents or an extended cuff for the graft can be used to induce spiral flow intentionally, which can further improve local hemodynamic environment and long-term prognosis.

Inherited Thoracic Aortic Disease: New Insights and Translational Targets.

Inherited thoracic aortopathies denote a group of congenital conditions that predispose to disease of the thoracic aorta. Aortic wall weakness and abnormal aortic hemodynamic profiles predispose these patients to dilatation of the thoracic aorta, which is generally silent but can precipitate aortic dissection or rupture with devastating and often fatal consequences. Current strategies to assess the future risk of aortic dissection or rupture are based primarily on monitoring aortic diameter. However, diameter alone is a poor predictor of risk, with many patients experiencing dissection or rupture below current intervention thresholds. Developing tools that improve the risk assessment of those with aortopathy is internationally regarded as a research priority. A robust understanding of the molecular pathways that lead to aortic wall weakness is required to identify biomarkers and therapeutic targets that could improve patient management. Here, we summarize the current understanding of the genetically determined mechanisms underlying inherited aortopathies and critically appraise the available blood biomarkers, imaging techniques, and therapeutic targets that have shown promise for improving the management of patients with these important and potentially fatal conditions.

Quantification of true lumen helical morphology and chirality in type B aortic dissections.

Chirality is a fundamental property in many biological systems. Motivated by previous observations of helical aortic blood flow, aortic tissue fibers, and propagation of aortic dissections, we introduce methods to characterize helical morphology of aortic dissections. After validation on computer-generated phantoms, the methods were applied to patients with type B dissection. For this cohort, there was a distinct bimodal distribution of helical propagation of the dissection with either achiral or exclusively right-handed chirality, with no intermediate cases or left-handed cases. This clear grouping indicates that dissection propagation favors these two modes, which is potentially due to the right-handedness of helical aortic blood flow and cell orientation. The characterization of dissection chirality and quantification of helical morphology advances our understanding of dissection pathology and lays a foundation for applications in clinical research and treatment practice. For example, the chirality and magnitude of helical metrics of dissections may indicate risk of dissection progression, help define treatment and surveillance strategies, and enable development of novel devices that account for various helical morphologies.NEW & NOTEWORTHY A novel definition of helical propagation of type B aortic dissections reveals a distinct bimodality, with the true lumen being either achiral (nonhelical) or exclusively right-handed. This right-handed chirality is consistent with anatomic and physiological phenomena such as right-handed twist during left ventricle contraction, helical blood flow, and tissue fiber direction. The helical character of aortic dissections may be useful for pathology research, diagnostics, treatment selection, therapeutic durability prediction, and aortic device design.

The long-term fate of renal and visceral vessel reconstruction after open thoracoabdominal aortic aneurysm repair.

OBJECTIVES: In the ever-advancing era of endovascular thoracoabdominal aneurysm (TAAA) repair, understanding long-term patency of renovisceral reconstructions after open TAAA repair provides important benchmarks. METHODS: Institutional open TAAA repair patient data were queried. Patients dying during index admission or with incomplete operative detail were excluded. Visceral and renal reconstructions were categorized as bypass, incorporation into a proximal or distal beveled aortic anastomosis, inclusion button, Carrel patch, or hybrid stent along with endarterectomy/stent adjuncts. Axial imaging or angiography determined long-term patency. Vessel event was defined as new occlusion or reintervention after repair. Overall time-to-event analysis was performed as well as separate analyses for each vessel (celiac, superior mesenteric artery [SMA], right renal, left renal) by reconstruction type utilizing Kaplan-Meier methods. Log-rank testing was employed to compare reconstructive strategies. RESULTS: Over 28 years, 604 repairs (type I, 106 [18%]; type II, 73 [12%]; type III, 195 [32%]; and type IV, 230 [38%]) were identified. Follow-up (median, 500 days) was available in 410/570 (72%) celiac, 406/573 (71%) SMA, 379/532 (71.2%) right renal, and 370/515 (72%) left renal reconstructions. There were five celiac, one SMA, eight right renal, and 10 left renal events. No type of reconstruction or adjunct was significantly associated with event. Overall 5-year patency of all renal/visceral reconstructions was 94% (95% confidence interval, 90%-96%). Estimated 5-year patency of the celiac, SMA, left renal, and right renal were similar, and were 99%, 100%, 97%, and 96%, respectively (P = .09). CONCLUSIONS: Visceral and renal long-term patency after open TAAA repair is excellent regardless of reconstructive technique. No differences are appreciated even when target vessel disease is addressed at the time of reconstruction. These findings continue to substantiate the effective long-term durability of open TAAA repair and are particularly germane to the ongoing evolution of endovascular strategies.

Evaluation of the Gore TAG thoracic branch endoprosthesis in the treatment of proximal descending thoracic aortic aneurysms.

BACKGROUND: Thoracic endovascular aortic repair has radically transformed the treatment of descending thoracic aortic aneurysms. However, when aneurysms involve the aortic arch in the region of the left subclavian artery, branch vessel preservation must be considered. Branched aortic endografts have provided a new option to maintain branch patency. METHODS: Six investigative sites enrolled 31 patients in a nonrandomized, prospective investigational device exemption feasibility trial of a single branched aortic endograft for the management of aneurysms that include the distal aortic arch. The Gore TAG thoracic branch endoprosthesis (W. L. Gore & Associates, Inc, Flagstaff, Ariz), an investigational device, allows for graft placement proximal to the left subclavian artery and incorporates a single side branch for left subclavian perfusion. RESULTS: All 31 patients (100%) had undergone successful implantation of the investigational device in landing zone 2. Men slightly outnumbered women (51.6%). Their average age was 74.1 ± 10.4 years. The aneurysm morphology was fusiform in 12 and saccular in 19 patients, with a mean maximum aortic diameter of 54.8 ± 10.9 mm. The mean follow-up period for the cohort was 25.2 ± 11.1 months. We have reported the patient outcomes at 1 month and 1 year. At 1 month, the side branch patency was 100% and the freedom from core laboratory-reported device-related endoleak (types I and III) was 96.7%, without 30-day death or permanent paraplegia. One patient experienced a procedure-related stroke. Through 1 year, five patients had died; none of the deaths were related to the device or procedure (clinical endpoint committee adjudicated). One thoracic reintervention was required. No conversions were required, and no aneurysm growth (core laboratory) was reported. One case of the loss of side branch patency was diagnosed in the left subclavian artery in an asymptomatic individual from computed tomography at 6 months, with no reported subsequent adverse events due to loss of patency. Endoleaks were reported by the core laboratory in five patients at 12 months (two, type II; and three, indeterminate). CONCLUSIONS: The present investigational device exemption feasibility study has reported the preliminary results of the use of a single side branch endograft to treat patients with proximal descending thoracic aortic aneurysms.

Performance of Viabahn balloon-expandable stent compared with self-expandable covered stents for branched endovascular aortic repair.

OBJECTIVE: The objective of this study was to compare the performance between the Viabahn balloon-expandable stent (VBX; Viabahn [W. L. Gore & Associates, Flagstaff, Ariz]) and a covered self-expandable stent (SES; Fluency [Bard Peripheral Vascular, Tempe, Ariz]) used as bridging stents for directional branches during fenestrated or branched endovascular aneurysm repair of complex aortic aneurysms. METHODS: Patients with thoracoabdominal aortic aneurysms (type I-IV) or pararenal aortic aneurysms either at high risk for open repair or unsuitable for endovascular repair with commercially available devices were prospectively enrolled in a physician-sponsored investigational device exemption trial. Descriptive statistics of the cohort included demographics, risk factors, and anatomic and device characteristics. Individual branches were grouped as either VBX or SES and had data analyzed for primary patency, branch-related type I or type III endoleaks, branch instability, branch-related secondary intervention, and branch-related aortic rupture or death. Categorical variables were expressed as total and percentage, and continuous variables were expressed as median (interquartile range). Kaplan-Meier curves were used to estimate long-term results. Groups were compared with the log-rank test. P value <.05 was considered statistically significant. RESULTS: During the period from July 2012 through June 2019, there were 263 patients treated for complex aortic aneurysm (thoracoabdominal aortic aneurysm) with fenestrated or branched endografts. The devices used were either custom-manufactured devices or off-the-shelf p-Branch or t-Branch (Cook Medical, Bloomington, Ind) devices. The median age was 71 years (interquartile range, 66-79 years); 70% were male, and 81% were white. The most common cardiac risk factors were smoking (92%), hypertension (91%), hyperlipidemia (78%), and chronic obstructive pulmonary disease (52%). The total number of vessels incorporated into the repair was 977, with branches representing 18.4% (179 branches). Among these 179 branches, the celiac artery, superior mesenteric artery, right renal artery, and left renal artery received 54 (30%), 56 (31%), 38 (21%), and 31 (18%) branches, respectively. VBX and SES groups represented 96 (54%) and 81 (46%) of the branches implanted. The celiac artery, superior mesenteric artery, right renal artery, and left renal artery received VBX as a bridging stent in 40%, 46.7%, 33.8%, and 32.2% respectively. The overall cohort survival rate was 78.5% at 24 months. There was no branch-related rupture or mortality. Primary patency at 24 months (VBX, 98.1%; SES, 98.6%; log-rank, P = .95), freedom from endoleak (VBX, 95.6%; SES, 98.6%; log-rank, P = .66), freedom from secondary intervention (VBX, 94.7%; SES, 98.1%; log-rank, P = .33), and freedom from branch instability (VBX, 95.6%; SES, 97.2%; log-rank, P = .77) were similar between groups. CONCLUSIONS: This initial experience with VBX stents demonstrated excellent primary patency and similarly low rates of branch-related complications and endoleaks, with no branch-related aortic rupture or death. Our results demonstrate that in a high-volume, experienced aortic center, the VBX stent is a safe and effective bridging stent option during branched endovascular aortic repair. Multicenter studies with a larger cohort and longer follow-up are necessary to validate these findings.

Unique characteristics of the type B aortic dissection patients with malperfusion in the Vascular Quality Initiative.

OBJECTIVE: Type B aortic dissection (TBAD) complicated by malperfusion carries high morbidity and mortality. The present study was undertaken to compare the characteristics of malperfusion and uncomplicated cohorts and to evaluate the long-term differences in survival using a granular, national registry. METHODS: Patients with TBAD entered into the thoracic endovascular aortic repair/complex endovascular aortic repair module of the Vascular Quality Initiative from 2010 to 2019 were included. The demographic, radiographic, operative, postoperative, in-hospital, and long-term reintervention data were compared between the malperfusion and uncomplicated TBAD groups using t tests and χ2 analysis, as appropriate. Overall survival was compared using Cox regression to generate survival curves. RESULTS: Of the 2820 included patients, 2267 had uncomplicated TBAD and 553 had malperfusion. The patients with malperfusion were younger (age, 55.8 vs 61.2 years; P < .001), were more often male (79.7% vs 68.1%; P < .001), had a higher preoperative creatinine (1.8 vs 1.1 mg/dL; P < .001), had more often presented with an American Society of Anesthesiologists class of 4 or 5 (81.9% vs 58.4%; P < .001), and had more often presented with urgent status (77.4% vs 32.8%; P < .001). In contrast, the uncomplicated TBAD group had had more medical comorbidities, including coronary artery disease and chronic obstructive pulmonary disease, and a larger aortic diameter (4.0 cm vs 4.9 cm; P < .001). The malperfusion group more frequently had proximal zones of disease in zones 0 to 2 (38.6% vs 31.5%; P = .002) and distal zones of disease in zones 9 and above (78.7% vs 46.2%; P < .001), with a greater number of aortic zones traversed (7.7 vs 5.1; P < .001) and a greater frequency of dissection extension into branch vessels (61.8% vs 23.1%; P < .001). Patients with malperfusion also exhibited greater case complexity, with a greater need for branch vessel stenting and longer procedure times. The overall incidence of postoperative complications was greater in the malperfusion group (39.4% vs 17.1%; P < .001) and included a greater rate of spinal cord ischemia (6.3% vs 2.2%; P < .001), acute kidney injury (10.4% vs 0.9%; P < .001), and in-hospital mortality (11.6% vs 5.6%; P < .001). In-hospital reintervention was also greater for the malperfusion patients (14.5% vs 7.4%; P < .001), although the incidence of long-term reinterventions was similar between the two groups (8.7% vs 9.7%; P = .548). A proximal zone of disease in zone 0 to 2 was associated with decreased survival. In contrast, a distal zone of disease in 9 and above, in-hospital reintervention, and long-term follow-up were associated with increased survival. Despite these differences, long-term survival did not differ between the malperfusion and uncomplicated groups (P = .320.) CONCLUSIONS: Patients presenting with TBAD and malperfusion represent a unique cohort. Despite the greater need for branch vessel stenting and in-hospital reintervention, they had similar long-term reintervention rates and survival compared with those with uncomplicated TBAD. These data lend insight with regard to the observed differences between uncomplicated and malperfusion TBAD.

Clinical trial outcomes and thoracic aortic morphometry after one year with the Valiant Navion stent graft system.

AUTHORS' NOTE: On February 17, 2021, Medtronic Incorporated issued a global voluntary recall of the Valiant Navion Thoracic Stent Graft System (the device under study in the Valiant Evo Global Clinical Program that is the subject of this publication), and instructed physicians to immediately cease use of the Valiant Navion system and return any unused product. Medtronic initiated the recall in response to three clinical trial subjects recently observed with stent fractures, two of whom have confirmed type IIIb endoleaks. The data collection, analysis, and manuscript submission occurred before the notice of this recall, and, specifically, the 100 procedures reviewed for this series were free of events at 1 year related to the reason for this device recall. The authors of this article and the manufacturer were unaware of the recently detected adverse events at the time of the preparation of the manuscript, and the 1-year trial results, and imaging-based analyses described are unchanged. Management of thoracic aortic aneurysms continues to be a challenging problem and outcomes are dependent on patient anatomy. The present publication focuses on the importance of achieving proximal and distal seals and the consideration of the temporal changes of the aortic morphology as a part of the TEVAR planning process. The authors believe there is still scientific merit in disclosing this information, despite the current nonavailability of the Valiant Navion system. OBJECTIVE: The Valiant Navion stent graft system (Medtronic Inc, Santa Rosa, Calif) is a third-generation device with improved conformability. We have reported the 1-year clinical trial outcomes, with a focus on an imaging-based analysis of the aortic morphology. We assessed the effects of graft implantation on the native anatomy and the effects of the 1-year changes in thoracic aorta morphology on the original seal zones of the stent graft. METHODS: A total of 100 subjects were enrolled in a prospective single-arm clinical trial investigating the Valiant Navion stent graft system. An independent core laboratory (Syntactx, New York, NY) assessed the anatomic characteristics and performance outcomes. RESULTS: Through 1 year of follow-up, the freedom from all-cause mortality, aneurysm-related mortality, and secondary procedures was 89.8%, 97.0%, and 94.8% respectively. Of the 100 patients, 5 had undergone a total of six secondary procedures, and 9 patients had developed an endoleak (type Ia and Ib in 1, type Ia in 1, type Ib in 3, and type II in 4 patients) within the first year. After 1 year, 2 of 76 patients (2.6%) had had an increase in their maximum aneurysm diameter of ≥5 mm, 62 (81.6%) had had stable sacs, and 12 (15.8%) had experienced sac shrinkage. Although no deployment failures had occurred, 36 of the 100 proximal (36%) and 31 of the 100 distal (31%) attachment zones were considered short according to our definitions. The stent graft had conformed to the native anatomy at implantation, because the preprocedural thoracic aorta tortuosity (1.45 ± 0.02) had not significantly changed at 1 month after implantation (1.46 ± 0.02). Despite a natural increase in thoracic tortuosity after 1 year (1.49 ± 0.02), wall apposition had been maintained over time, as evidenced by the low endoleak rates. Aortic elongation and dilation had occurred at the proximal end of the graft by an average of 1.2 mm and 1.6 mm, respectively. Aortic remodeling was more pronounced at the distal end, with an average increase of 4.2 mm in length and 2.8 mm in diameter. CONCLUSIONS: The included patients had had positive 1-year outcomes with high freedom from mortality, endoleak development, and secondary procedures. Aortic elongation and dilation were more prevalent at the distal end, emphasizing the importance of distal attachment zone consideration as part of preoperative planning. Because aortic remodeling can be expected to continue over time, additional follow-up and imaging analysis in the trial will be necessary to assess the aortic morphology and its effects on stent graft performance.

Influence of thoracic endovascular aortic repair on true lumen helical morphology for Stanford type B dissections.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) can change the morphology of the flow lumen in aortic dissections, which may affect aortic hemodynamics and function. This study characterizes how the helical morphology of the true lumen in type B aortic dissections is altered by TEVAR. METHODS: Patients with type B aortic dissection who underwent computed tomography angiography before and after TEVAR were retrospectively reviewed. Images were used to construct three-dimensional stereolithographic surface models of the true lumen and whole aorta using custom software. Stereolithographic models were segmented and co-registered to determine helical morphology of the true lumen with respect to the whole aorta. The true lumen region covered by the endograft was defined based on fiducial markers before and after TEVAR. The helical angle, average helical twist, peak helical twist, and cross-sectional eccentricity, area, and circumference were quantified in this region for pre- and post-TEVAR geometries. RESULTS: Sixteen patients (61.3 ± 8.0 years; 12.5% female) were treated successfully for type B dissection (5 acute and 11 chronic) with TEVAR and scans before and after TEVAR were retrospectively obtained (follow-up interval 52 ± 91 days). From before to after TEVAR, the true lumen helical angle (-70.0 ± 71.1 to -64.9 ± 75.4°; P = .782), average helical twist (-4.1 ± 4.0 to -3.7 ± 3.8°/cm; P = .674), and peak helical twist (-13.2 ± 15.2 to -15.4 ± 14.2°/cm; P = .629) did not change. However, the true lumen helical radius (1.4 ± 0.5 to 1.0 ± 0.6 cm; P < .05) and eccentricity (0.9 ± 0.1 to 0.7 ± 0.1; P < .05) decreased, and the cross-sectional area (3.0 ± 1.1 to 5.0 ± 2.0 cm2; P < .05) and circumference (7.1 ± 1.0 to 8.0 ± 1.4 cm; P < .05) increased significantly from before to after TEVAR. The distinct bimodal distribution of chiral and achiral native dissections disappeared after TEVAR, and subgroup analyses showed that the true lumen circumference of acute dissections increased with TEVAR, although it did not for chronic dissections. CONCLUSIONS: The unchanged helical angle and average and peak helical twists as a result of TEVAR suggest that the angular positions of the true lumen are constrained and that the endografts were helically conformable in the angular direction. The decrease of helical radius indicated a straightening of the corkscrew shape of the true lumen, and in combination with more circular and expanded lumen cross-sections, TEVAR produced luminal morphology that theoretically allows for lower flow resistance through the endografted portion. The impact of TEVAR on dissection flow lumen morphology and the interaction between endografts and aortic tissue can provide insight for improving device design, implantation technique, and long-term clinical outcomes.

Adjunctive branch interventions during thoracic endovascular aortic repair for acute complicated type B dissection are not associated with inferior outcomes.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) has been shown to effectively treat malperfusion associated with acute type B thoracic aortic dissection (TBAD). A subset of patients might still require adjunctive peripheral or visceral artery branch interventions during TEVAR to remedy persistent end organ malperfusion. Our objectives were to determine the incidence of these adjunctive interventions and to compare the outcomes between patients who had and had not undergone such interventions. METHODS: We performed a retrospective review of the TEVAR and complex EVAR module of the Vascular Quality Initiative from 2010 to 2019 to identify all patients treated for malperfusion due to acute TBAD. The anatomic branch and procedure performed at TEVAR were recorded. The 30-day mortality, need for reintervention, complication rates, and overall survival were compared between these patients stratified by adjunctive intervention status. RESULTS: A total of 426 patients had undergone TEVAR for acute TBAD with end organ malperfusion. Of the 426 patients, 126 (29.6%) had undergone 182 adjunctive branch interventions during TEVAR. The most common interventions were stenting (n = 86; 47.3%) and stent grafting (n = 49; 26.9%), with the most common site being the left renal artery (n = 49; 26.9%). The patients in both groups had similar 30-day mortality (12.4% with branch intervention vs 15.6% without; P = .511) and rates of in-hospital reintervention (19.2% with branch intervention vs 20.7% without; P = .732). No differences were found in the rates of postoperative complications or overall survival at 3 years between the two groups. CONCLUSIONS: Adjunctive peripheral and visceral artery branch interventions in conjunction with TEVAR for acute TBAD with malperfusion occurred in one third of index cases, but did not predispose patients to worse overall outcomes. Adjunctive arterial branch interventions should be included in the treatment paradigm for acute TBAD with end organ malperfusion that does not improve with primary entry tear coverage alone.

Morphologic characteristics and endovascular management of acute type B dissection patients with superior mesenteric artery involvement.

OBJECTIVE: Despite its association with static mesenteric malperfusion, the morphologic characteristics and optimal management of acute type B aortic dissection (ABAD) with superior mesenteric artery (SMA) involvement are poorly understood. We studied the associated risk factors and reported the outcomes of endovascular treatment. METHODS: From May 2016 to May 2018, we examined 212 consecutive patients with ABAD in our center. Those with SMA involvement (SMAI) were included in the present study and divided into those with and without mesenteric malperfusion (MMP) according to the clinical findings. After thoracic endovascular aortic repair (TEVAR) with or without SMA revascularization, we compared the clinical data, imaging results, and outcomes for those with and without MMP. RESULTS: Computed tomography angiography confirmed 44 cases of SMAI: 12 (27.3%) with MMP and 32 (72.7%) without MMP. The patients with MMP had presented more frequently with lower extremity malperfusion (33.3% vs 3.1%; P = .023) than had those without MMP, with an odds ratio of 14.15 (P = .047). Multivariate analysis showed that patients with a low true lumen (TL)/false lumen (FL) diameter ratio of the SMA (TL/FL-SMA <1) had a greater risk of developing MMP than those with a high TL/FL-SMA ratio of >1 (odds ratio, 8.49; 95% confidence interval, 1.24-58.26; P = .029). SMA TL thrombosis was a significant predictor of the requirement for additional SMA revascularization after TEVAR among patients with MMP (P = .045). During a mean 10-month follow-up period, complete FL thrombosis in the SMA was seen in 11 patients (25%; 33.3% with MMP vs 21.9% without MMP; P = .43). The overall mortality rate was 6.82% (16.7% in the MMP group and 3.1% in the non-MMP group; P = .09). CONCLUSIONS: In the present study, limb ischemia and the TL/FL-SMA ratio were two independent predictors for the development of MMP in patients with ABAD and SMAI. We found that TEVAR can be safely performed for these patients, and SMA TL thrombosis predicted for the need for SMA revascularization.

Fenestrated versus debranching thoracic endovascular aortic repair for endovascular treatment of distal aortic arch and descending aortic lesions.

BACKGROUND: Cervical debranching, followed by thoracic endovascular aortic repair (TEVAR), is well-established for treating aortic arch lesions. However, total endovascular repair with fenestrated endografts has not been adequately studied. Thus, we performed a comparison of the two techniques. METHODS: The present study was a single-center, retrospective study comparing the treatment of thoracic aortic lesions with custom-made fenestrated stent-grafts (fenestrated TEVAR [fTEVAR]) with a single fenestration for the left subclavian artery (LSA), a scallop for the left carotid artery, and hybrid repair with a thoracic stent-graft and cervical debranching of the LSA. Emergency cases were excluded. RESULTS: From 2012 to 2018, 19 patients (58% male) underwent elective fTEVAR (group A) and 17 patients (82% male) underwent debranching TEVAR (dTEVAR; group B). The mean age ± standard deviation in group A was 65.8 ± 2 years and 68 ± 3 years in group B. Left carotid-subclavian bypass was performed in 15 of 17 patients (88%) and transposition of the LSA in 2 of 17 patients (12%) in group B. The two groups were comparable regarding comorbidities, except for peripheral arterial disease: 5 of 19 patients in group A (26%) and none in group B had had peripheral arterial disease (P = .049). Dissection or post-dissection aneurysm was the indication for treatment in 6 of 19 patients in the fTEVAR group (group A) and in 12 of 17 patients in the dTEVAR group (group B; 31.6% vs 70.6%; P = .04). The indication for the remaining patients was a degenerative aortic aneurysm. Technical success was achieved in all cases, except for one case of dTEVAR owing to a type Ia endoleak. The mean endovascular operative time was 191 ± 120 minutes for fTEVAR and 130 ± 75 minutes for dTEVAR (P = NS). The mean operative time for the debranching procedure was 181 ± 97 minutes. No deaths or major strokes had occurred in the early postoperative period (30 days). Of the 17 patients in group B, 5 (29.4%) had experienced a local complication related to the debranching procedure. The mean follow-up was 14.6 ± 2 months for group A and 17 ± 2 months for group B. Of the 19 patients in group A and 17 patients in group B, 2 (10.5%) and 6 (35.3%) had required an unplanned reintervention related to the thoracic stent-graft during the follow-up period, respectively (P = NS). The estimated freedom from unplanned reintervention at 12 months was 86% for group A and 81% for group B. Primary patency of the LSA stent-graft or the carotid-subclavian bypass/transposition was 100% in both groups. CONCLUSIONS: Both techniques showed excellent midterm patency rates for the target vessel and high technical success rate. The operation times were shorter for the fTEVAR group and complications related to the debranching procedure were avoided.

Impact of bridging stent design and configuration on branch vessel durability after fenestrated endovascular repair of complex aortic aneurysms.

OBJECTIVE: The ideal mating stent for target vessel revascularization in fenestrated endovascular aneurysm repair (FEVAR) of juxtarenal and thoracoabdominal aortic aneurysms remains unknown. The objective of this study was to assess the outcomes associated with use of different stent types and configurations mated with reinforced fenestrations during FEVAR. METHODS: Clinical data from patients undergoing FEVAR for juxtarenal and thoracoabdominal aortic aneurysms in a prospective physician-sponsored investigational device exemption trial were analyzed. Outcomes for two different balloon-expandable covered stents (BECSs) mated with reinforced fenestrations were assessed along with the impact of distal extension with a self-expanding stent (SES). Primary patency, branch-related endoleak, and reintervention rates were determined. Cox proportional hazards model was used for time-to-event analysis. RESULTS: From 2001 to 2016, there were 918 patients who underwent fenestrated or branched endograft repair of complex aortic aneurysms; 1604 renal arteries (RAs), 714 superior mesenteric arteries (SMAs), and 333 celiac arteries (CAs) were mated with reinforced fenestrations using JOMED (n = 2014; Abbott Vascular, Santa Clara, Calif) or iCAST (n = 637; Atrium Medical, Hudson, NH) BECSs. The type of BECS did not affect short-term or long-term patency, branch-related endoleaks, or reintervention rates in the RA, SMA, or CA. Twenty-five percent (402/1604) of RAs, 84% (598/714) of SMAs, and 8% (27/333) of CAs underwent distal SES extension at the index operation. RAs with a distal SES in addition to the BECS had a higher likelihood of an occlusion event (hazard ratio, 2.791; 95% confidence interval, 1.42-5.48; P = .003) and reinterventions (P = .036) compared with those without an SES. Addition of a distal SES to the BECS in the SMA or CA did not have an impact on patency or reintervention rates. CONCLUSIONS: BECS choice does not appear to have an impact on branch durability after FEVAR. Selective distal SES placement in RAs with high-risk anatomy does not appear to significantly protect against an occlusion event or to prevent secondary interventions. Routine addition of a distal SES does not improve SMA fenestration durability.

Thoracic aortic remodeling with endografting after a decade of thoracic endovascular aortic repair experience.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) results have been studied in short-term time frames. This study aimed to evaluate midterm and long-term outcomes of TEVAR, emphasizing postoperative aortic remodeling and need for reintervention. METHODS: This is an institutional retrospective review of TEVAR for isolated descending thoracic aortic aneurysms. Data were collected from 2004 to 2018. Primary outcomes studied included aneurysm sac remodeling, freedom from reintervention, and all-cause mortality. Other outcomes studied include endoleak rates, neurologic complication rates, and any overall postoperative complication rates. RESULTS: During the study period, 219 patients underwent TEVAR for descending thoracic aortic aneurysms. The median effect of TEVAR on sac diameter was a 0.7-cm decrease in size (interquartile range, -1.4 to 0.0 cm). During the study period, 80% (n = 147) of patients experienced aneurysm sac regression or stability. Perioperative neurologic complications occurred in 16% (n = 34) of patients. Significant predictors of sac growth were endoleak (odds ratio [OR], 65; P < .001), preoperative carotid-subclavian bypass (OR, 8; P = .003), and graft oversizing <20% (OR, 15; P = .046). Every 1-mm increase in aortic diameter at the proximal TEVAR landing zone led to an increased odds of endoleak (OR, 2; P = .049). Access complications (OR, 8) and subclavian artery coverage (OR, 6) significantly increased the odds of reintervention, whereas every percentage of graft oversizing protected against reintervention (OR, 0.005). Life-table analysis revealed an overall survival of 78% (71%-83%) at median follow-up. At 3 years, survival was 88% (80%-93%) for those with aneurysm sac stability or regression, whereas it was 70% (49%-84%) for those with aneurysm sac growth (P = .0402). Cox proportional hazards model showed that the only protective factor for mortality was percentage oversizing, with every 1% of oversizing having a hazard ratio (HR) of <.001 (P = .032). This was counterbalanced by the fact that patients with graft oversizing >30% had an increased odds of mortality with HR >10 (P = .049). Other significant factors that increased the odds of mortality included endoleak (HR, 3.6; P = .033), diabetes (HR, 4.1; P = .048), age (every 1-year increase in age; HR, 1.2; P = .002), year of surgery (every year subsequent to 2004; HR, 1.3; P = .012), and peripheral artery disease (HR, 5.2; P = .041). CONCLUSIONS: The majority of patients (80%) experience sac stability or regression after TEVAR, which offers a clear survival advantage. Endoleaks are predictive of sac growth, conferring increased mortality. Rigorous surveillance is necessary to prevent future aortic events through reintervention.

The provisional extension to induce complete attachment technique is associated with abdominal aortic remodeling and reduces aorta-related adverse events after aortic dissection.

OBJECTIVE: This study evaluated the efficacy of the provisional extension to induce complete attachment (PETTICOAT) technique for type B and postoperative residual type B aortic dissections compared with the conventional thoracic endovascular aortic repair (TEVAR) technique. METHODS: In this retrospective study, we compared sequential aortic morphologic changes in consecutive patients with type B and postoperative residual type B aortic dissections treated with the PETTICOAT technique between January 2016 and December 2017 with patients treated with the conventional TEVAR between January 2013 and December 2015. Outcomes included aortic remodeling and aorta-related adverse events for 2 years postoperatively. RESULTS: Forty-eight patients were included in this study (24 in the PETTICOAT group, 24 patients in the conventional TEVAR group). Although both groups showed aortic remodeling in the descending thoracic aorta, the PETTICOAT group developed significantly better aortic remodeling in the abdominal aorta compared with the conventional TEVAR group during the observation period. The PETTICOAT group had significantly fewer aorta-related adverse events compared with the conventional TEVAR group (8% vs 54%; P < .001). Aorta-related adverse events more commonly occurred in the poor remodeling group compared with in the good remodeling group (P = .001; hazard ratio, 8.32; 95% confidence interval, 2.26-30.64). CONCLUSIONS: This study suggests that the PETTICOAT technique for aortic dissection may promote aortic remodeling and decrease the incidence of aorta-related adverse events. Additional studies are required to confirm these preliminary findings.

Effects of preoperative visceral artery stenosis on target artery outcomes after fenestrated/branched endovascular aortic aneurysm repair.

OBJECTIVE: Target artery stenosis might affect the outcomes of fenestrated/branched endovascular aortic aneurysm repair (F-BEVAR). The aim of the present study was to assess the effects of preoperative stenosis of the celiac artery (CA) and superior mesenteric artery (SMA) on the target artery outcomes after F-BEVAR. METHODS: During a 4-year period, 287 consecutive patients, 204 men (71%) and 83 women (29%), had undergone F-BEVAR using fenestrated (83%), fenestrated-branched (4.5%), branched (3.5%), and off-the-shelf t-Branch (9%) devices (Cook Medical Inc, Bloomington, Ind). Preoperative SMA and CA significant stenosis was defined as a computed tomography angiography-based intraluminal diameter reduction >50%. The primary endpoints included primary patency, freedom from target vessel instability, and patient survival. RESULTS: The median patient age was 71 years (interquartile range, 67-77 years). Suprarenal (36%), juxtarenal (25%), and thoracoabdominal (39%) aortic aneurysms were treated. The technical success rate was 99%. The 30-day survival was 97%. Among 981 stented vessels, 179 (18%) were CAs and 270 (27.5%) were SMAs. Significant preoperative CA stenosis was identified in 39 patients (22%) and SMA stenosis in 24 (9%). The median follow-up was 29.9 months. The primary patency rates at 12, 36, and 60 months were 98%, 92%, and 92% for the CA and 99%, 98%, and 98% for the SMA, respectively. Primary patency was significantly lower in the patients with previous significant CA stenosis than in those without stenosis (83%, 83%, and 76% vs 100%, 100%, and 97% at 12, 36, and 60 months, respectively; P < .01). Freedom from celiac branch instability was also significantly lower among patients with significant stenosis (84%, 84%, and 76% vs 100%, 93%, and 93% at 12, 36, and 60 months; P < .01). The presence of significant SMA stenosis did not affect either primary patency or freedom from target vessel instability. The survival rates at 12, 36, and 60 months were significantly lower for the patients with CA stenosis than for those without stenosis (67%, 61%, and 55% vs 90%, 84%, and 82%, respectively; P < .01). Similarly, lower survival rates were observed for patients with significant SMA stenosis (70%, 60%, and 60% vs 87%, 79%, and 78% at 12, 36, and 60 months, respectively; P = .04). CONCLUSIONS: F-BEVAR was associated with overall primary patency rates >90% for the CA and SMA. Preoperative CA stenosis was associated with lower primary patency and freedom from target vessel instability. In contrast, neither SMA branch primary patency nor freedom from target vessel instability were affected by preoperative SMA stenosis. We found visceral artery stenosis was a marker of atherosclerosis burden associated with reduced mid- and long-term patient survival.