Late Aortic Remodeling after Endovascular Repair of Complicated Type B Aortic Dissection—TEVAR Protects Only the Covered Segment of Thoracic Aorta

Clinical outcomes and aortic remodeling after Castor single-branched stent-graft implantation for type B aortic dissections involving left subclavian artery

Background

The left subclavian artery (LSA) can be intentionally covered by a stent graft to acquire adequate landing zones for a proximal entry tear near the LSA during thoracic endovascular aortic repair (TEVAR). The Castor single-branched stent graft is designed to treat type B aortic dissection (TBAD) to retain the LSA during TEVAR. This study investigates clinical outcomes, aortic remodeling, and abdominal aortic perfusion patterns after TEVAR with the novel Castor device.

Methods

From November 2020 to June 2023, 29 patients with TBAD involving the LSA were treated with the Castor single-branched stent graft. In-hospital clinical outcome and aortic computed tomography angiography (CTA) data were analyzed. CTA was performed preoperatively and at follow-up to observe stent morphology; branch patency; endoleak; change in true lumen (TL), false lumen (FL), and transaortic diameters; and abdominal aortic branch perfusion pattern.

Results

The technical success rate was 96.6%. One failure was that the branch section did not completely enter the LSA and the main body migrated distally. No in-hospital mortality, paraplegia, or stroke occurred. During follow-up, one type Ib endoleak, four distal new entry tears, and one recurrent type A dissection arose from a new entry tear at the ascending aorta, no stent migration was observed, and the branch patency rate was 100%. At the thoracic aorta, TL diameters significantly increased, FL diameters markedly decreased, and FL was partially or completely thrombosed in most patients at follow-up. At the abdominal aorta, we observed 33.3% of TL growth and 66.7% of TL stabilization or shrinkage. The initial TL ratio at iliac bifurcation negatively predicted abdominal TL growth after TEVAR with a cutoff of 21.0%. Of the 102 abdominal aortic branches, 94.1% of the branches showed no change in perfusion pattern, 3.9% of the branches had an increased TL perfusion, and 2.0% of the branches had an increased FL contribution.

Conclusion

The Castor unibody single-branched stent graft offers an efficient endovascular treatment for TBAD involving the LSA. TEVAR with the Castor device effectively induced thoracic FL thrombosis and thoracic TL enlargement and resulted in abdominal TL growth when the initial TL ratio at iliac bifurcation is less than 21.0%. Abdominal aortic branch perfusion patterns remain relatively stable after TEVAR with the Castor stent graft.

STABILISE (Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair) Is Associated With Good Anatomical Results on the Distal Thoracoabdominal Aorta at 2 Years

PURPOSE

The aim of this comparative study was to evaluate the increased aortic diameter of the distal aorta after implementing the STABILISE technique in complicated type B aortic dissection (AD).

DESIGN

This is a comparative monocentric retrospective study.

MATERIALS AND METHODS

All patients who underwent an STABILISE procedure for complicated AD between 2018 and 2020 were included and compared with a historic cohort treated with thoracic endovascular aortic repair (TEVAR) alone. Aortic diameters were measured at 6 different levels on the thoracic and abdominal aorta. The primary end point was an increased aortic diameter at 1 and 2 years. The exclusion criterion was the absence of a computed tomography (CT) scan at 1 or 2 years.

RESULTS

A total of 55 patients were included: 24 in the TEVAR group and 31 in the STABILISE group. At the level of the stent graft, there was a decrease in aortic diameters in both groups without significant differences. At the level of the distal aorta, there was an increase in aortic diameters in both groups without significant differences. There were significantly more patients in the TEVAR group with an unfavorable increase in aortic diameter >5 mm of the distal aorta at 2 years than in the STABILISE group: 8 (33%) vs 1 (3%) (p=0.01). For chronic ADs, a significantly greater increase in aortic diameters of the distal aorta was observed in the STABILISE group.

CONCLUSIONS

The STABILISE technique is technically feasible and potentially leads to decreased longer re-intervention rates; indeed, more patients had an unfavorable increase in aortic diameter in the TEVAR group than in the STABILISE group at 2 years. The high rate of long-term distal aortic aneurysm progression and reintervention after TEVAR alone suggests that this option is not sufficient to definitively treat these complex patients.

CLINICAL IMPACT

This article reported the results of stent assisted balloon induced intimal disruption and relamination (STABILISE) with a follow-up at 2 years. This is the first comparative study between STABILISE, which has emerged as a new technique inducing aortic remodeling and therefore better long-term outcome, and the standard technique TEVAR alone. STABILISE technique is associated with good results on the distal aorta at 2 years with a rate of patient with unfavorable aortic diameter evolution greater in TEVAR group compared to STABILISE group and could improve the long-term results on the distal aorta by inducing extensive aortic remodeling.

Preoperative Predictors of Late Aortic Expansion in Acute Type B Aortic Dissection Treated with TEVAR

BACKGROUND

A patent false lumen (FL) in patients with thoracic endovascular aortic repair (TEVAR)-treated type B aortic dissection (TBAD) can cause a significant risk for late aortic expansion (LAE). We hypothesize that preoperative features can predict the occurrence of LAE.

METHODS

Sufficient preoperative and postoperative follow-up clinical and imaging feature data for patients treated with TEVAR in the First Affiliated Hospital of Nanjing Medical University from January 2018 to December 2020 were collected. A univariate analysis and multivariable logistic regression analysis were used to find potential risk factors of LAE.

RESULTS

Ninety-six patients were finally included in this study. The mean age was 54.5 ± 11.7 years and 85 (88.5%) were male. LAE occurred in 15 (15.6%) of 96 patients after TEVAR. Two preoperative factors showed strong associations with LAE according to the multivariable logistic regression analysis: preoperative partial thrombosis of the FL (OR = 10.989 [2.295-48.403]; p = 0.002) and the maximum descending aortic diameter (OR = 1.385 [1.100-1.743] per mm increase; p = 0.006).

CONCLUSIONS

Preoperative partial thrombosis of the FL and an increase in the maximum aortic diameter are strongly associated with late aortic expansion. Additional interventions of the FL may help to improve the prognosis of patients with the high risk of late aortic expansion.

MANAGEMENT OF LEFT SUBCLAVIAN ARTERY IN TYPE-B AORTIC DISSECTION TREATED WITH THORACIC ENDOVASCULAR AORTA REPAIR

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has been the favored approach for the treatment of type B aortic dissection (TBAD). To obtain an adequate proximal landing zone, coverage of the left subclavian artery (LSA) will often be necessary. The occurrence of possible neurologic complications has continued to be debated. We investigated the management of the LSA in patients with TBAD undergoing endovascular repair.

METHODS

We searched the PubMed and MEDLINE databases to October 2020 for studies of TEVAR for TBAD. Data on the study design, demographics, endograft details, LSA coverage and revascularization, mortality, complications, and follow-up were extracted and analyzed. The effects of LSA coverage and revascularization on neurologic complications and outcomes were investigated.

RESULTS

A total of 26 reports (24 retrospective and 2 prospective) were deemed eligible for our study. A total of 1483 patients (mean age, 56.9 ± 6.2 years) had undergone TEVAR for acute (n = 932; 62.9%), subacute (n = 36; 2.4%), or chronic (n = 515; 34.7%) TBAD, with a success rate of 97.8% and hospital mortality of 4.9%. The LSA origin had been covered for 707 patients (47.7%), and 326 had undergone LSA revascularization (surgical, n = 96; endovascular, n = 170; unspecified or not reported, n = 60). LSA revascularization was concomitant for 68.1% of cases, after TEVAR for 1.8%, and not reported for 30.1%. Of 1146 patients, 10 (0.9%) had experienced left arm claudication, and the overall stroke rate was 3.3% (2.7% for the LSA group and 1% for the uncovered LSA group; P = .0815). Of the patients with stroke and a covered LSA, 1% (2 of 203) had undergone LSA revascularization and 4.8% (5 of 105) had not (P = .0478). Twenty-six patients (1.9%) had developed paraplegia: 0.7% (3 of 433) with a covered LSA, 1.4% (7 of 491) with an uncovered LSA (P = .3508), and not reported for 16 patients. Endoleak was present in 138 patients (13.4%) at a mean follow-up of 32.1 ± 25.6 months.

CONCLUSIONS

Our review has shown that LSA coverage during endovascular repair for complicated TBAD will does not significantly increase the risk of neurologic complications; however, revascularization of the LSA should be always recommended.

Progressive Aortic Enlargement in Medically Managed Acute SVS/STS Type B Aortic Dissections with Visceral Aortic Involvement

BACKGROUND

Aortic remodeling of the thoracic aorta has been studied in patients treated with medical or endovascular therapy for the treatment of acute aortic dissections; however, particular attention has not yet focused on identifying specific growth patterns and rates across all aortic zones. Additionally, previous studies have not delineated between dissections with and without visceral aortic involvement, and we hypothesize that these two cohorts may exhibit distinct differences. The aim of this study is to investigate aortic behavior over time in medically managed acute SVS/STS Type B dissections with visceral aortic involvement, and identify potential associations of subsequent aortic behavior with clinical outcomes.

METHODS

A single-center retrospective review was performed of all patients between 2010-2020 with acute SVS/STS Type B aortic dissections with visceral aortic involvement that were not surgically managed. Short-axis centerline measurements of the true/false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone, including non-dissected zones. Measurements were taken at the time of diagnosis and at six subsequent yearly intervals. Diameter changes over time were evaluated using repeated measures mixed models linear growth analysis. Aortic enlargement was classified by growth in TAD≥5mm in either the thoracic (Thoracic Segment Enlargement [TSE], Zone 0-4) or visceral segments (Visceral Segment Enlargement [VSE], Zone 5-9).

RESULTS

A total of 78 patients were identified with a median length of follow-up of 3.3 years (interquartile range [IQR]1.3-6.6 years). Follow-up past 5 years was seen in 31% of the cohort. For the entire cohort, mean thoracic growth in TAD was 2.0±2.0 mm/year and visceral growth in TAD 2.5±2.4 mm/year. TSE was observed in 65% of patients, with a median time until onset of 0.8 years (IQR 0.4-2.3 years). VSE was observed in 57% of the cohort, with a median time until onset of 1.6 years (IQR 0.9-3.3 years). Repeat measures mixed models linear growth analysis identified significant predictable linear growth in all aortic zones except for the non-dissected Zones 0-2. Odds for TSE are significantly increased in patients with known genetically triggered aortic conditions (GenTACs) (OR 2, 95% CI 1.8-4.5, p=0.044) and in cases where the dissection entry tear was in either Zone 1 or 2 (OR 4.8, 95% CI 1.2-8.4, p=0.044). In adjusted regression analysis, odds for intervention in the thoracic aorta were significantly increased in patients with rapid TSE in Zone 3 (OR 3.6 [1.1-8.4], p=0.045). Similarly, odds for intervention targeting the visceral aortic segment were significantly increased in patients with Zone 9 VSE (OR 9.3, 95% CI 1.1-13.3, p=0.014). Odds for 5-year all-cause mortality were significantly increased in cases with large thoracic aneurysms (OR 6.1, 95% CI 1.1-14.9, p=0.042).

CONCLUSIONS

Aortic enlargement was present in the majority of patients with medically managed acute SVS/STS Type B aortic dissections with visceral aortic involvement, with analysis demonstrating predictable linear growth in all dissected zones. Patients with aortic instability demonstrated higher gross changes in diameter in addition to higher yearly rates of change compared to all comers. Odds for enlargement were impacted by both patient demographic and anatomic dissection characteristics. Growth in Zone 3 and Zone 9 significantly increased odds for aortic intervention. Odds for 5-year mortality were significantly increased in the presence of large thoracic aneurysms. Results highlight risk of progressive degeneration beyond acute phase in SVS/STS Type B aortic dissections with visceral aortic involvement, with life-long surveillance remaining crucial in management of dissections.

Aortic Visceral Segment Instability is evident following Thoracic Endovascular Aortic Repair for Acute and Subacute Type B Aortic Dissection

BACKGROUND

Anatomic remodeling within the thoracic aorta following thoracic endovascular aortic repair (TEVAR) for type B aortic dissections (TBAD) has been well documented, but less is known about the response of the untreated visceral aorta. This study aims to investigate visceral aortic behavior following TEVAR for acute or subacute TBAD and identify associations with clinical outcomes.

METHODS

A multi-center retrospective review was performed of all imaging for all patients treated with TEVAR for acute (0-14 days) and subacute (14-90 days) non-traumatic TBAD between 2006-2020. Cohort was inclusive of uncomplicated, high-risk, and complicated (defined per SVS reporting guidelines) dissections. Centerline aortic measurements of the true and false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone (zones defined by SVS reporting guidelines). Diameter changes over time were evaluated using repeated measures mixed effects linear growth modeling. Visceral segment instability (VSI) was defined as any growth in TAD ≥ 5mm within aortic zones 5 through 9.

RESULTS

A total of 82 patients were identified. Median length of imaging follow-up was 2.1 years (IQR 3.9 years), with 15% of the cohort having follow-up longer than 5 years. VSI was present in 55% of the cohort, with an average maximal increase in TAD of 10.4±6.3 mm over a median follow-up of 2.1 years (IQR 3.9 years). Roughly a third of the cohort experienced rapid VSI (growth ≥5mm in first year), and 4.8% of the cohort developed a large para-visceral aneurysm aortic (TAD≥5cm) secondary to VSI. Linear growth modeling identified significant predictable growth in TAD across all visceral zones. Zones 7 had the highest rate of TAD dilation, with a fixed effect estimated rate of 1.3 mm per year (95%-CI 0.23-2.1, p=0.022). The preoperative factor most strongly associated with VSI was ≥6 cumulative number of zones dissected (OR 6.4, 95% OR 1.07-8.6, p=0.041). Odds for aortic reintervention were significantly increased in cases where VSI led to development of a para-visceral aortic aneurysm ≥5cm development (OR 3.7, 95%-CI 1.1-13, p=0.038).

CONCLUSION

VSI was identified in the majority of patients treated with TEVAR for management of acute and subacute TBAD. Preoperative anatomic features such as extent of dissection, rather than procedural details of graft coverage, may play a more significant role in VSI occurrence. Importantly, significant TAD growth occurred in all visceral segments. These results highlight the importance of lifelong surveillance following TEVAR, and identify a subset of patients that may be at increased risk for re-intervention.

Remodeling of Aortic Configuration and Abdominal Aortic Branch Perfusion After Endovascular Repair of Acute Type B Aortic Dissection: A Computed Tomographic Angiography Follow-Up

Background: Thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) induces false lumen (FL) thrombosis, promotes favorable aortic remodeling, and makes an impact on abdominal aortic branch perfusion patterns. However, little is known about the long-term fate of aortic remodeling and abdominal aortic branch perfusion after TEVAR for TBAD and the effect of FL thrombosis status on these changes.

Materials and methods: Between January 2014 and May 2021, 59 enrolled patients with acute TBAD were treated with TEVAR and had post-operative or follow-up images. Pre-operative, post-operative, and latest follow-up CT angiography (CTA) data were analyzed for the largest diameter of true lumen (TL), FL, and transaorta and for the FL thrombosis status on the stented thoracic aorta, unstented thoracic aorta, and abdominal aorta. Abdominal aorta perfusion patterns were characterized.

Results: The mean follow-up period was 17.1 months. In the stented thoracic aorta, average TL diameters increased, average FL diameters decreased, and average transaortic diameters did not change; 82.6% of the patients had either a stable or shrinking transaortic size and 87% of the patients achieved total FL thrombosis. In the unstented thoracic aorta, average TL diameters increased, transaortic growth and no changes occurred in 39.1 and 45.7% of the patients, respectively, and complete FL thrombosis was present in 50% of the patients. In the abdominal aorta, average FL and transaortic diameters increased, aorta was expanded in 52.2% of the patients, and FL remained patent in 65.2% of the patients. Of the 354 branches, 37 branches (10.5%) exhibited changes in perfusion patterns, 22 branches (6.2%) demonstrated an increased TL perfusion, and 15 branches (4.2%) had an increased FL contribution. Compared with patent or partially thrombosed FL, complete FL thrombosis was accompanied by a bigger decrease in FL diameters, a larger increase in TL diameters, and a higher percentage of abdominal branch TL perfusion.

Conclusions: In majority of the patients, TEVAR stabilized the size of the stented thoracic aorta, namely TL expansion and FL obliteration. However, abdominal aortic FL remained patent FL, and it was expanded with the resultant transaortic growth over a long follow-up period. Abdominal aortic branch perfusion patterns remained largely stable after TEVAR. The failure to achieve FL thrombosis negatively affects the remodeling of a contagious abdominal aortic dissection.

Flow density of computed tomography aortography for predicting early unfavorable aortic remodeling after TEVAR in type IIIb aortic dissection

OBJECTIVE

Patients diagnosed of DeBakey type III aortic dissection with partial thrombosis of false lumen (FL) have a higher mortality rate. However, IIIb dissections with full patent FL tend to exhibit a partially thrombosed FL quickly after thoracic endovascular aortic repair (TEVAR); thus, we investigated survival and aortic remodeling in this population.

METHODS

We reviewed computed tomography aortograms (CTAs) of 123 patients with TEVAR-treated IIIb aortic dissections from July 2006 to June 2015; contrast density of CTAs represented intraluminal flow. Patients were selected to fit in 2 groups of FL in term of FL contrast density: low flow (LF) group (non-opacification in the midway of FL) and high flow (HF) group (full patent FL).

RESULTS

Surgical mortality was 10.3% in the HF group and 4.5% in the LF group (n = 61; LF = 22; HF = 39). 3 patients in the HF group suffered from lethal aortic rupture in 10 days postoperatively. The HF group showed significant increase in maximal diameter, and had larger thoracic (+4.00 ± 2.68 vs -1.16 ± 3.42 mm, P < .001) aortic diameter expansion from preoperation to one week postoperation. Both groups exhibited significant favorable thoracic TL expansion and maximal aortic diameter shrinkage in postoperative one week to one year. However, HF group displayed less thoracic aortic FL regression (-70.9 ± 83.5 vs -113.9 ± 95.0 cm³, P = .1) and TL expansion (+14.5 ± 27.2 vs +36.8 ± 28.3 cm³, P = .008) when compared to LF group.

CONCLUSIONS

Preoperative HF in the FL has an unfavorable effect on thoracic aortic diameter in one week post-TEVAR. This might increase the risk of aortic rupture.

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.

Comparison of aortic remodelling after conservative treatment or thoracic endovascular repair in type B dissections

OBJECTIVES

Our aim was to compare aortic remodelling in type B dissections after thoracic endovascular aortic repair (TEVAR) or conservative treatment.

METHODS

We conducted a retrospective analysis of computed tomography (CT) data sets at dissection onset and at the last follow-up in a group with conservative (group A) and TEVAR treatment (group B). An additional analysis of the preoperative CT images was performed in patients from group A, who were converted to TEVAR during follow-up. Diameters and lengths of all aortic segments were measured and growth rates were calculated.

RESULTS

We included 74 patients: 50 patients in group A (follow-up time: 1625 ± 209 days) and 24 patients in group B (follow-up time: 554 ± 129 days). The mean aortic diameter growth rate was significantly higher in group A than in group B in the mid-descending aorta (A: +7 mm/year; B: -4 mm/year; P = 0.003). Length growth difference was only present in the abdominal aortic segment and was more pronounced in group A (+2 vs ±0 mm/year; P = 0.009). The conversion rate from conservative treatment to TEVAR was 36% (n = 18). A false lumen diameter of >22 mm at baseline was associated with a higher rate of conversion (P = 0.036). After conversion, the mean growth rate in the proximal descending and mid-descending aorta decreased from preoperative +11 and +18 mm/year to postoperative -9 and -14 mm/year, respectively (P < 0.001).

CONCLUSIONS

In acute type B dissections, TEVAR stops aortic enlargement in the thoracic aorta, but promotes distal dilatation compared to the conservative treatment group. After conversion to TEVAR in conservatively pretreated chronic type B dissections, a more pronounced diameter decrease in the descending aorta was observed than in patients treated in the acute phase.