Severe Tortuosity of the Distal Descending Thoracic Aorta Affects the Accuracy of Distal Deployment During a Thoracic Endovascular Aortic Repair

PURPOSE

An accurate distal deployment is essential for successful thoracic endovascular aortic repair (TEVAR) of a paradiaphragmatic aortic aneurysm. This study aimed to investigate the anatomical and intraoperative factors that affect the accuracy of distal deployment during TEVAR.

METHODS

We conducted a retrospective review of preoperative and postoperative computed tomography scans of 426 patients undergoing TEVAR at our institution between October 2008 and May 2021, of which the stent-graft was attempted to be deployed just above the celiac axis or the superior mesenteric artery in 56 patients. Based on the anatomical factors related to the malposition (deployed >10 mm away from the target vessel) and the greater curve to the straight-line ratio (G/S ratio), the patients were categorized as severe tortuosity (n=21) and mild tortuosity (n=35) groups to compare the operative and clinical outcomes.

RESULT

Stent-graft malpositioning occurred in 21 cases. Among all anatomical variables, only the G/S ratio was significantly larger in the malpositioned cases (p=0.049). A cutoff G/S ratio value of 1.15 was determined using the receiver operating curve analysis. In the severe tortuosity group, the distal end of the stent-graft was significantly farther (median: 10.0 [interquartile range (IQR): 2.5-19.5] mm vs 3.0 [0-8.0] mm; p=0.015) from the target vessel, and the tilt angle of the stent-graft's distal edge was larger (median: 21.4 [IQR: 15.8-24.5] vs 9.5 [5.5-12.5] degree; p<0.01) than that in the mild tortuosity group. Both groups were comparable for the incidence of a primary type Ib endoleak (p=0.454), a secondary type Ib endoleak (p=1.0), and the rate of distal reintervention (p=0.276).

CONCLUSION

Severe tortuosity in the distal descending thoracic aorta is associated with a malpositioned and tilted distal end of the stent-graft.

CLINICAL IMPACT

Thoracic endovascular aortic repair (TEVAR) for paradiaphragmatic thoracic aortic aneurysms requires accurate distal landing. In this paper, a retrospective CT analysis revealed that the greater curve to the straight-line ratio (G/S ratio) was associated to affects the malposition of the stent graft, defined as being deployed more than 10 mm away from the target vessel. Further, a comparative analysis based on the G/S ratio demonstrated that severe aortic tortuosity was associated with a more distal and tilted deployment of the stent graft.

Distal landing zone outcomes in thoracic endovascular aortic aneurysm repair with challenging morphology: a propensity-matched comparison of distal active fixation versus standard stent-graft

BACKGROUND

To evaluate the distal landing zone (LZ) outcomes in adverse morphology after thoracic endovascular repair (TEVAR) with distal active fixation (DAF) stent-grafts compared with standard endografts.

METHODS

between 2006 and the 31st December 2020, sixty-nine DAFs (study group) and sixty-nine standard stent-grafts (control group) were enrolled in a multi-center, retrospective, case-control study. The primary outcomes were the distal endoleak and reintervention. The secondary outcomes were: distal segment migration, wedge apposition and related complications. A univariate and multivariate logistic regression followed by a propensity-scored model (1:1) were performed.

RESULTS

The results were reported for the DAF vs control group. The mean follow-up was 3.3 ± 2.1 vs 3.7 ± 3.4 years. The distal endoleak rate was 7.3% vs 27.5% (P=0.011). The freedom from distal endoleak was 95%, 95% and 91% vs 85%, 76%, and 73% at 1, 3 and 5 years respectively (Log-rank P=0.011). Tortuosity index and distal thoracic aorta angulation were predictors of endoleak (P=0.012 and P=0.029 respectively). The distal reinterventions rate was 7.3% vs 20.3% (P=0.026). The freedom from distal reinterventions was 95%, 95% and 91% vs 92%, 75% and 75% at 1, 3 and 5 years respectively (Log-rank P=0.041). The wedge apposition was 5.8 vs 13.0-mm (P<0.000). The distal segment migration was upward directed in all cases and was significant (>10- mm) in 13.0% vs 39.1% (P=0.000).

CONCLUSIONS

The DAF stent-graft showed a significant reduction of the distal endoleak rates and other specific outcomes of the distal LZ in patients with an adverse anatomy.

Bail-Out Pull-Through Pull-Back Technique for Accidental Coverage of the Left Common Carotid Artery During Thoracic Endovascular Aortic Repair

PURPOSE

We describe a pull-through pull-back technique to revascularize the left common carotid artery (LCCA) that was unintentionally covered during thoracic endovascular aortic repair (TEVAR).

CASE REPORT

A 69-year-old man presented with back pain secondary to acute type B aortic dissection with an intimal tear in the proximal descending aorta. Serial computed tomography (CT) revealed an enlarged descending aorta and proximal progression of the aortic dissection. He underwent left carotid-subclavian artery bypass and TEVAR, 10 days after admission. The Valiant Navion stent graft without a bare stent was deployed proximally; however, the LCCA was unintentionally covered by the stent graft during this procedure. A pull-through form was created between the left axillary and femoral arteries using a 0.035-inch guide wire. The pull-through guide wire was gently pulled, and the greater curvature of the proximal end of the stent graft was displaced distally. Angiography confirmed restoration of antegrade blood flow into the LCCA. The patient's postoperative course was uneventful. Follow-up CT performed 6 months postoperatively confirmed preserved blood flow into the LCCA without endoleak nor stent migration.

CONCLUSION

The pull-through pull-back technique is a feasible troubleshooting strategy for accidental coverage of supra-aortic vessels during TEVAR.

A preliminary analysis of late structural failures of the Navion stent graft in the treatment of descending thoracic aortic aneurysms

OBJECTIVE

Patients in the Valiant Evo U.S. and international clinical trials had positive short-term outcomes; however, late structural failures, including type IIIb endoleaks have been recently discovered. Type IIIb endoleaks are serious adverse events because the repressurization of the aneurysm sac increases the risk of rupture. The purpose of the present study was to detail the imaging patterns associated with the structural failures with the aim of increasing awareness of failing graft presentation, early recognition, and prompt treatment.

METHODS

The Valiant Evo clinical trial was a prospective, single-arm investigation of a thoracic stent graft system. With the recent late structural failures, sites were requested to submit all available imaging studies to date to allow the core laboratory to assess for structural failures such as type IIIb endoleaks, stent ring fractures, and stent ring enlargement. Of the 100 patients originally enrolled in the trial from 2016 to 2018, the core laboratory assessed the imaging studies performed at ≥1 year for 83 patients.

RESULTS

No structural failures of the graft were reported through 1 year of follow-up. At 1 to 4 years, graft structural failures were detected in 11 patients with descending thoracic aortic aneurysms. Of the 11 patients, 5 had a type IIIb endoleak. Four of the five had imaging findings showing stent fractures consistent with the location of the graft seam and one had a type IIIb endoleak attributed to calcium erosion with no stent fracture or ring enlargement. Of the four patients with stent fracture in line with the graft seam, three underwent a relining procedure that successfully excluded the type IIIb endoleak. One of these three patients died 4 days later of suspected thoracic aortic rupture because the distal thoracic endovascular aortic repair extension had been landed in a previously dissected and fragile section of the aorta. The remaining six patients had had stent ring enlargement. One of the six patients had had persistent aneurysm expansion from the time of implantation onward and had died of unknown causes. The remaining five patients have continued to be monitored.

CONCLUSIONS

In the present preliminary analysis, the imaging patterns associated with type IIIb endoleaks, stent fractures, and stent ring enlargement appear to be related to the loss of seam integrity or detachment of the stent rings from the surface of the graft material. The imaging patterns we have detailed should be closely monitored using computed tomography angiography surveillance to allow structural failures to be promptly identified and treated.

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.

Outcomes of thoracic endovascular aortic repair in thoracic aortic aneurysm and penetrating aortic ulcer using the Conformable Gore TAG within and outside the instructions for use

OBJECTIVE

To describe the outcome of thoracic endovascular aortic repair (TEVAR) in thoracic aortic aneurysm and penetrating aortic ulcer with respect to instructions for use status.

METHODS

Between October 2009 and September 2017, a total of 532 patients underwent TEVAR; of which 195 have been treated using the Conformable GORE® TAG® thoracic endoprosthesis (CTAG). Fifty-six patients of this cohort underwent TEVAR for thoracic aortic aneurysm/penetrating aortic ulcer using the CTAG. Depending on the preoperative computed tomography angiography findings, patients were classified as inside or outside the device's instructions for use. All inside instruction for use patients underwent postoperative reclassification regarding the instructions for use status. Study endpoints included TEVAR-related reintervention, exclusion of the pathology (endoleak type I/III), TEVAR-related mortality, and graft-related serious adverse events. The median duration of follow-up was 29.7 months (range: 0-109.4 months).

RESULTS

Of the 56 patients, 17 were primarily classified as outside instruction for use, and in additional 13 patients, TEVAR was performed outside instruction for use, leading to 30 outside instruction for use patients (53.6%). Twenty-six patients (46.4%) were treated inside instruction for use. Reintervention-free survival was lower in outside instruction for use patients (P = 0.016) with a hazard ratio of 9.74 (confidence interval 1.2-80.2; P = 0.034) for TEVAR-related reintervention. With respect to endoleak type I/III, relevant difference was detected between inside/outside instruction for use status (P = 0.012). The serious adverse event rate was 30.4%, mainly in outside instruction for use patients (P = 0.004). Logistic regression analysis indicated an association between graft-related serious adverse event/instructions for use status (odds ratio 6.11; confidence interval 1.6-30.06; P = 0.012). In-hospital death was seen more frequently in outside instruction for use patients (P = 0.12) as was procedure-related death (log-rank test: P = 0.21).

CONCLUSION

TEVAR for thoracic aortic aneurysm/penetrating aortic ulcer is frequently performed outside instruction for use despite preoperative inside instruction for use eligibility, leading to important consequences for technical/clinical outcome. Instructions for use adherence in TEVAR should be of interest for further large-scale studies.

A multicenter "real-world" study of the valiant NAVION stent graft

BACKGROUND

The aim of the present study was to evaluate early results of thoracic endovascular aortic repair (TEVAR) using the Valiant Navion™ stent graft in a "real-world" scenario.

METHODS

All patients who underwent TEVAR with the Valiant Navion™ endograft between November 2018 and November 2019 were included in this retrospective multicenter study (six European centers). The primary endpoints were technical success, incidence of major adverse events (MAEs), access failure, deployment failure, deployment accuracy, and rate of intraoperative endoleaks (ELs).

RESULTS

One hundred-sixteen patients with varying thoracic aortic diseases were included. Eighteen patients (15.5%) were treated for an off-label condition. The technical success rate was 100%, without any access or deployment failures. The proximal and distal deployment accuracy rates were 99.1% and 97.4%, respectively. There were no intraoperative MAEs, including death. Two (1.7%) type Ib ELs were detected at the first postoperative CTA, all of which were in off-label procedures and related to the short length of the sealing neck. No type III ELs were detected. The median hospitalization time was 8 days (IQR 4-12), including a median intensive care unit stay of 1 day (IQR 1-2). The in-hospital mortality rate was 4.3%. At a median follow-up time of 98 days (IQR 39-187), there were no aortic-related mortalities or new onset of endoleaks.

CONCLUSION

Our initial experience with the Valiant Navion™ endograft in a wide variety of aortic diseases showed safe early outcomes, especially for on-label procedures.

Thoracic Endovascular Aortic Repair in the Setting of Compromised Distal Landing Zones

BACKGROUND

The short-term and intermediate-term outcomes of two distinct approaches to thoracic endovascular aortic repair (TEVAR) for descending aortic aneurysms in patients with compromised distal landing zones are reported.

METHODS

Fifty-one patients (38 female, average age 72 ± 9 years) underwent 55 TEVARs (2008 to 2018) for aneurysmal disease. Inclusion criteria consisted of TEVAR in a compromised distal landing zone, defined as follows: diameter 3.5 cm or greater; cross-sectional thrombus 50% or greater; or 25% or greater circumferential mural calcification in the 2 cm supraceliac aorta; or tortuosity index of 1.1 or more over the 10 cm supraceliac aorta. Treatment cohorts were (1) TEVAR alone (n = 29), and (2) TEVAR with adjunct consisting of visceral snorkel graft with distal stent extension (n = 20) or EndoAnchors (Medtronic, Minneapolis, MN [n = 6]).

RESULTS

Perioperative complication rate was 20%. Thirty-day mortality was 5% including one access-site related intraoperative death and one postoperative death from embolic mesenteric ischemia. Median clinical follow-up was 2.2 years. Intermediate-term outcomes include type 1B endoleaks, 35%; 0.5 cm or more per year maximal aortic diameter growth, 9%; reintervention, 15%; and all-cause mortality, 25%. The distal landing zone diameter increased by 0.3 cm per year in the TEVAR alone cohort; however, it decreased by 0.1 cm per year in the adjunct cohort ( P = .04).

CONCLUSIONS

Thoracic endovascular aortic repair is a viable alternative for the treatment of thoracoabdominal aortic aneurysms in patients with compromised distal landing zones, although these patients may benefit significantly from the development of branched thoracoabdominal devices. In the interim, the use of TEVAR adjuncts may limit progressive degeneration of the distal landing zone in this patient population.

Endo-Bentall for proximal aortic dissection: from conception to application

The endovascular treatment of pathologies of the ascending aorta has not been incorporated into routine clinical practice. The aim of this article is to provide an overview of the endovascular treatment of pathologies of the ascending aorta, particularly type A aortic dissection. A thorough analysis and discussion of anatomical, physiological, clinical and technical challenges, and obstacles is performed. Conventional straight stent-grafts alone are not capable of fixing the entire complex underlying problem in the vast majority of patients with acute type A aortic dissection. An endovascular valve-carrying conduit consisting of a proximal transcatheter aortic valve connected to a covered stent-graft would be able to close a primary entry tear in the ascending aorta, ensure coronary perfusion, initiate true lumen expansion, treat malperfusion, treat aortic regurgitation, drain any pericardial effusion through a transapical approach, and possibly stabilize the distal aorta. Two thirds of all patients with acute aortic dissection are potential candidates for endovascular treatment, and the concept may help to significantly improve survival in patients with acute aortic dissection.

Evaluation of EndoAnchor Aortic Wall Penetration After Thoracic Endovascular Aortic Repair

Purpose: To analyze aortic wall penetration of Heli-FX EndoAnchors after use in seal zones in the aortic arch or descending thoracic aorta during thoracic endovascular aortic repair (TEVAR). Materials and Methods: From May 2014 to May 2019, 25 patients (mean age 70.5±10 years; 16 women) were treated with TEVAR and adjunctive use of the Heli-FX device in 3 academic vascular surgery departments. Computed tomography scans were retrospectively reviewed to determine the location [arch or descending thoracic aorta (DTA)] of the EndoAnchors and the adequacy of aortic wall penetration, defined as adequate (≥2 mm), partial (<2 mm), or inadequate wall penetration (including loss). Endoleaks, reinterventions, and mortality were assessed. Results: A total of 161 EndoAnchors were deployed (median 7 per patient, range 4–9). Twenty-two EndoAnchors were place in the arch (zones 0–2) and 139 in the DTA (zones 3–5). A larger proportion of arch deployments (27%) had suboptimal penetration compared with the DTA (6.5%; p<0.005), resulting in a 91% adequate wall penetration rate for the series overall. Three EndoAnchors were lost (and only 1 retrieved) in 3 different patients, with no additional morbidity; thus, an overall deployment success rate of 88% was achieved. At a mean follow-up of 16.6±14 months, 4 patients required 5 (successful) reinterventions, including one for a type Ia endoleak treated with chimney TEVAR. One patient died 10 months after treatment due to endograft infection, without an opportunity for surgical correction. Conclusion: EndoAnchors have a higher risk of maldeployment in the arch, though this may be attributable to the small learning curve experience in this location. The best aortic wall penetration for this series was in the DTA, where EndoAnchors proved useful for distal endograft fixation during TEVAR.

Decreased biventricular function following thoracic endovascular aortic repair

OBJECTIVES

Preclinical studies have suggested acute stiffening of the aorta following experimental thoracic endovascular aortic repair (TEVAR), resulting in acute elevated pulse pressure, hypertension and possibly heart failure. The aim of this study was to evaluate cardiac remodelling following TEVAR.

METHODS

From 2005 to 2018, 519 TEVAR procedures were performed at a single centre. Transthoracic echocardiography was performed pre- and post-TEVAR in 31 patients without previous replacement of the thoracic aorta. Patient characteristics, drug information, radiographic and follow-up data were evaluated. Aortic details were measured in multiplanar reconstruction.

RESULTS

Transthoracic echocardiography was performed 2 ± 2 years after TEVAR. At this time, patients received significantly more antihypertensive drugs compared to the pre-TEVAR intake (beta-blocker therapy: P = 0.037; calcium channel blocker: P = 0.022). Compared to pre-TEVAR, there was a significant reduction in the left ventricular ejection fraction (P = 0.008) and tricuspid annular plane systolic excursion (P = 0.013) post-TEVAR. A significant increase in the left ventricular mass was not detected in this study (P = 0.95). The mean distance of 163 ± 66 mm of the descending aorta was covered.

CONCLUSIONS

This study suggests negative cardiac remodelling with a decrease in the left and right ventricular function following TEVAR despite an increase in oral antihypertensive medication. The impact of stiffer endovascular grafts compared with the native aortic wall should be considered by endovascular specialists and manufacturers.

A New Methodology to Determine Apposition, Dilatation, and Position of Endografts in the Descending Thoracic Aorta After Thoracic Endovascular Aortic Repair

Purpose: To validate computed tomography angiography (CTA)–applied software to assess apposition, dilatation, and position of endografts in the proximal and distal landing zones after thoracic endovascular aortic repair (TEVAR) of thoracic aortic aneurysm. Materials and Methods: Twenty-two patients (median age 75.5 years; 11 men) with a degenerative descending thoracic aortic aneurysm treated with TEVAR with at least one postoperative CTA were selected from a single center’s database. New CTA-applied software was used to determine the available apposition surface in the proximal and distal landing zones, apposition of the endograft fabric with the aortic wall, shortest apposition length, endograft inflow and outflow diameters, shortest distance between the left subclavian artery and the proximal endograft fabric, and shortest distance between the celiac trunk and the distal endograft fabric on each CTA. Interobserver variability for these parameters was assessed with the repeatability coefficient and the intraclass correlation coefficient. Results: Excellent interobserver agreement was found for all measurements. Interobserver variability of surface and shortest apposition length calculations was larger for the distal site compared with the proximal site, with a mean difference of 10% vs 2% of the mean available apposition surface, 12% vs 5% of the endograft apposition surface, and 16% vs 8% of the shortest apposition length, respectively. Inflow and outflow diameters of the endograft showed low variability, with a mean difference of 0.1 mm with 95% of the interobserver difference within 1.8 mm. Mean interobserver differences of the proximal and distal shortest fabric distances were 1.0 and 0.9 mm (both 2% of the mean lengths). Conclusion: Assessment of apposition, dilatation, and position of the proximal and distal parts of an endograft in the descending thoracic aorta is feasible after TEVAR with the new software. Interobserver agreement for all measured parameters was excellent for the proximal and distal landing zones. The new method allows detection of subtle changes during follow-up. However, a larger study is needed to quantify how parameters change over time in complicated and uncomplicated TEVAR cases and to define the real added value of the new methodology.