Analysis of Aortic Arch Hemodynamics With Simulated Bird's Beak Effects

OBJECTIVE

The objective of this study was to investigate the flow effects in different degrees of thoracic aortic stent graft protrusion extension by creating bird beak effect simulations using accurate 3D geometry and a realistic, nonlinear, elastic biomechanical model using computer-aided software SolidWorks.

METHODS

Segmentation in 3D of an aortic arch from a computed tomography (CT) scan of a real-life patient was performed using SolidWorks. A parametric analysis of three models was performed: (A) Aortic arch with no stent, (B) 3 mm bird-beak configuration, and (C) 6.5 mm bird-beak configuration. Flow velocity, pressure, vorticity, wall shear stress (WSS), and time average WSS were assessed.

RESULTS

The flow velocity in Model A remained relatively constant and low in the area of the ostium of the brachiocephalic artery and doubled in the left subclavian artery. On the contrary, Models B and C showed a decrease in velocity of 52.3 % in the left subclavian artery. Furthermore, Model B showed a drop in velocity of 82.7% below the bird-beak area, whereas Model C showed a decline of 80.9% in this area. The pressure inside the supra-aortic branches was higher in Model B and C compared with Model A. In Model A, vorticity only appeared at the level of the descending aorta, with low to non-vorticity in the aortic arch. In contrast, Models B and C had an average vorticity of 241.4 Hz within the bird beak area. Regarding WSS, Model A, and Model B shared similar WSS in the peak systolic phase, in the aortic arch, and the bird beak area, whereas Model C had an increased WSS by 5 Pa on average at these zones.

CONCLUSION

In the present simulations' lower velocities, higher pressures, vortices, and WSS were observed around the bird beak zone, the aortic arch, and the supra-aortic vessels.

Comparison of bare and nonbare stent grafts during thoracic endovascular aneurysm repair of the aortic arch

OBJECTIVE

We compared the outcomes of patients treated with nonbare stents (NBS) and proximal bare stents (PBS) endografts with a proximal landing zone in the aortic arch during thoracic endovascular aortic repair (TEVAR).

METHODS

We conducted a retrospective cohort, observational, multicenter study that included 361 consecutive TEVAR procedures undertaken between November 2005 and December 2021. TEVAR patients with both BS and NBS Relay stent graft configurations with proximal landing in zones 1, 2, or 3 were enrolled. Preoperative anamnestic and morphological data, clinical outcomes, and aortic modifications 30 days after surgery and at the latest follow-up available were collected. The primary outcome was freedom from proximal endoleak (type IA) comparing the two configurations. Total and detailed endoleak rates, clinical and technical success, intraoperative additional maneuvers, major adverse events, and reinterventions were secondary outcomes.

RESULTS

The median follow-up was 4.9 (interquartile range, 2.0-8.1) years. No statistically significant difference between NBS and PBS patients concerning 30-day major adverse events, retrograde aortic dissection, disabling stroke, or late type IA endoleak (10.8% vs 7.8%; P = .597). Aneurysmal disease (P = .026), PLZ diameter of >34 mm (P = .026), aortic tortuosity index of >1.4 (P = .008), type III aortic arch (P = .068), and PLZ thrombus (P = .014) identified as risk factors by univariate Cox regression analysis. PLZ thrombus was the only type IA endoleak risk factor at multivariate Cox regression (P = .016).

CONCLUSIONS

We found no statistically significant difference in freedom from type IA endoleak, retrograde dissection, or disabling stroke observed between the NBS and the BS configuration of the Relay endograft. Proximal landing zone thrombotic apposition was a prominent risk factor for type IA endoleak after TEVAR.

Open Versus Zone 0/1 Endovascular Aortic Repair for Arch Aneurysm: A Propensity Score-Matched Study from the National Clinical Database in Japan

BACKGROUND

Although open surgical repair (OSR) is the gold standard for treating arch aneurysms, thoracic endovascular aortic repair (TEVAR) may be a less invasive alternative. However, it remains unclear which of the 2 methods yields better outcomes. In this study, we compared the perioperative outcomes of both procedures for arch aneurysms using a nationwide surgical database.

METHODS

Data of patients who underwent elective aortic repair for true arch aneurysms were extracted from the National Clinical Database of Japan. Patients who underwent OSR and Zone 0/1 TEVAR were matched in a 1:1 ratio using propensity scores and their mortality and morbidity rates were compared.

RESULTS

A total of 2,815 and 1,125 patients underwent OSR and Zone 0/1 TEVAR, respectively. After propensity score matching, 1,058 patients were included in both groups. Compared with OSR, Zone 0/1 TEVAR was associated with a significantly higher incidence of stroke (5.8 vs. 10.0%, P < 0.001) and paraplegia/paraparesis (1.6 vs. 4.4%, P < 0.001). However, there were no significant differences in the 30-day and operative mortality rates between the 2 groups (2.2 vs. 2.7% and 4.5 vs. 5.4%, respectively). In the Zone 0/1 TEVAR group, postoperative computed tomography was performed in 92.4% of patients, and types I and III endoleaks were identified in 6.4% and 1.1% of patients, respectively.

CONCLUSIONS

Zone 0/1 TEVAR has higher incidences of stroke and paraplegia/paraparesis than OSR, with a risk of postoperative endoleaks. Resolving these problems is the key for expanding the application of Zone 0/1 TEVAR and in the meantime OSR remains the gold standard for surgically fit patients.

Efficacy of Endovascular Repair Using Single Left Common Carotid Artery Stent Combined with Castor Single-Branched Stent-Graft in the Treatment of Regional Diseases of Zone 2 of the Aorta

PURPOSE

To observe the short-term efficacy of thoracic endovascular aortic repair (TEVAR) using a single left common carotid artery chimney stent combined with a Castor single-branched stent-graft (SC-TEVAR) in the treatment of zone 2 (Z2) aortic diseases.

MATERIALS AND METHODS

To conduct a retrospective analysis of 20 patients with Z2 aortic diseases who were treated in our department from June 2021 to April 2022. The lesions included true aortic degenerative aneurysms with diameter ≥5.0 cm and penetrating aortic ulcers with depth >1.0 cm or basal width >2.0 cm. All 20 patients accepted the SC-TEVAR treatment, which was a new hybrid method to assure the flow of the left common carotid artery (LCCA) and left subclavian artery (LSA). This method was defined as a concomitant chimney stent for LCCA and a Castor single-branched stent graft for the aorta and LSA. The baseline data and intraoperative data were collected to evaluate the safety and efficacy of this method. The patency of the target blood vessel and any associated complications were evaluated at 1 and 6 months postoperatively, to analyze the safety and efficacy of this new method.

RESULTS

After discharge from the hospital, all patients were followed up by a specific follow-up team. At 6 monthly follow-up period, there were no cardiac events, stroke, hemiplegia, type I endoleak, type II endoleak, proximal stent graft-induced new entries, distal stent graft-induced new entries, wound infection, or bleeding. Only 1 patient developed an inguinal wound hematoma and got conservative treatment. Importantly, no patients developed stenosis or occlusion of the LCCA or LSA. The patency of branched arteries was 100%. The technical success rate was 90%.

CONCLUSION

SC-TEVAR appears to be a new and relatively simple, safe, and effective treatment for Z2 aortic diseases.

CLINICAL IMPACT

This was a single-center retrospective cohort study. A total of 20 patients with zone 2 aortic diseases accepted a new hybrid surgical method named SC-TEVAR. This method was not complicated and could be finished with only 3 peripheral artery exposure. The result showed no mortality, 100% patency of the branch artery, and 90% of technical success in 6 months of follow-up time. SC-TEVAR showed a satisfactory result in this retrospective study and could be promoted as an easy method to treat zone 2 aortic diseases.

A meta-analysis on the effect of proximal landing zone location on stroke and mortality in thoracic endovascular aortic repair

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) involving the aortic arch may increase the opportunity for stroke owing to disruption of cerebral circulation and embolization. In this study, a systematic meta-analysis was performed to examine the impact of proximal landing zone location on stroke and 30-day mortality after TEVAR.

METHODS

MEDLINE and Cochrane Library were searched for all original studies of TEVAR reporting outcomes of stroke or 30-day mortality for at least two adjacent proximal landing zones, based on the Ishimaru classification scheme. Forest plots were created using relative risks (RR) with 95% confidence intervals (CI). An I2 of <40% was regarded as minimal heterogeneity. A P value of <.05 was considered significant.

RESULTS

Of the 57 studies examined, a total of 22,244 patients (male 73.1%, aged 71.9 ± 11.5 years) were included in the meta-analysis, with 1693 undergoing TEVAR with proximal landing zone 0, 1931 with zone 1, 5839 with zone 2, and 3089 with zone 3 and beyond. The overall risk of clinically evident stroke was 2.7% for zones ≥3, 6.6% for zone 2, 7.7% for zone 1, and 14.2% for zone 0. More proximal landing zones were associated with higher risks of stroke compared with distal (zone 2 vs ≥3: RR, 2.14; 95% CI, 1.43-3.20; P = .0002; I2 = 56%; zone 1 vs 2: RR, 1.48; 95% CI, 1.20-1.82; P = .0002; I2 = 0%; zone 0 vs 1: RR, 1.85; 95% CI, 1.52-2.24; P < .00001; I2 = 0%). Mortality at 30 days was 2.9% for zones ≥3, 2.4% for zone 2, 3.7% for zone 1, and 9.3% for zone 0. Zone 0 was associated with higher mortality compared with zone 1 (RR, 2.30; 95% CI, 1.75-3.03; P < .00001; I2 = 0%). No significant differences were found in 30-day mortality between zones 1 and 2 (P = .13) and between zone 2 and zones ≥3 (P = .87).

CONCLUSIONS

The risk of stroke from TEVAR is lowest in zone 3 and beyond, increasing significantly as the landing zone is moved proximally. Furthermore, perioperative mortality is increased with zone 0 compared with zone 1. Therefore, risk of stent grafting in the proximal arch should be weighed against alternative surgical or nonoperative options. It is anticipated that the risk of stroke will improve with further development of stent graft technology and implantation technique.

DeBakey Type II Acute Aortic Dissection Distant From the Proximal Edge of a Stent Graft: A Case Report Nine Years After Thoracic Endovascular Aortic Repair

An 84-year-old male with a medical history notable for prior thoracic endovascular aortic repair for thoracic aneurysm nine years ago presented to the emergency department with a chief complaint of transient loss of consciousness. A brain computed tomography showed no remarkable findings. A subsequent computed tomography scan for comprehensive evaluation revealed DeBakey type II acute aortic dissection as evidenced by contrast-enhanced imaging. An intimal tear was found on the ascending aorta distant from the proximal edge of a stent graft. Due to the urgency of the situation, the patient underwent emergent ascending aortic replacement. Following the successful intervention, the patient was transferred to a specialized rehabilitation facility with the goal of facilitating further improvement in their condition.

Expert opinion: How to treat type IA endoleakage

Type Ia endoleaks due to failed sealing or loss of landing zone and the adequate management thereof remain crucial for long-term therapeutic success following TEVAR. This expert opinion summarizes our institutional experience with endovascular, open surgical, and hybrid techniques in the context of recent scientific publications. The rapid turnover of technical innovations, but most importantly outcome data demonstrate the requirement for increasingly patient-tailored treatment strategies and the need for specialized aortic centers. The latter should offer a complete range of treatment options, an adequate perioperative management, and the highest level of multidisciplinary expertise.

Assessment of the Effectiveness of Zone 1-Landing Hybrid TEVAR by Comparing Its Outcomes with Those of Zone 2-Landing Hybrid TEVAR

Background: Hybrid thoracic endovascular aortic repair (TEVAR) without median sternotomy is increasingly being performed in high-risk patients with aortic arch disease. The outcomes of hybrid TEVAR were reported to be worse with a more proximal landing zone. This study aims to clarify the effectiveness of zone 1-landing hybrid TEVAR by comparing the outcomes of zone 2-landing hybrid TEVAR. Methods: From April 2008 to October 2020, 213 patients (zone 1: zone 1-landing hybrid TEVAR, n = 82, 38.5%; zone 2: zone 2-landing hybrid TEVAR, n = 131, 61.5%) were enrolled (median age, 72 years; interquartile range [IQR], 65-78 years), with a median follow-up period of 6.0 years (IQR, 2.8-9.7 years). Results: The mean logistic EuroSCORE was 20.9 ± 14.8%: the logistic EuroSCORE of the zone 1 group (23.3 ± 16.1) was significantly higher than that of the zone 2 group (19.3 ± 12.4%, p = 0.045). The operative time and hospital stay of the zone 1 group were significantly longer than those of the zone 2 group. On the other hand, the in-hospital and late outcomes did not differ significantly between the two groups. There were no significant differences in cumulative survival (66.8% vs. 78.0% at 10 years, Log-rank p = 0.074), aorta-related death-free rates (97.6% vs. 99.2% at 10 years, Log-rank p = 0.312), and aortic event-free rates (81.4% vs. 87.9% at 10 years, Log-rank p = 0.257). Conclusions: Zone 1- and 2-landing hybrid TEVAR outcomes were satisfactory. Despite the high procedural difficulty and surgical risk, the outcomes of zone 1-landing hybrid TEVAR were equal to those of zone 2-landing hybrid TEVAR. If the surgical risk is high, zone 1-landing hybrid TEVAR should not be avoided.

Clinical outcomes of Najuta thoracic stent graft system for arch aneurysms

Objectives

We aimed to elucidate the perioperative and short-term clinical outcomes of the Najuta thoracic stent graft system with fenestrations for supra-aortic vessels.

Methods

We retrospectively investigated the perioperative and short-term clinical outcomes of 20 patients treated for arch or distal arch aneurysms using the Najuta thoracic stent graft system during the period from May 2019 to February 2023.

Results

The technical success rate of the Najuta thoracic stent graft system was 95%. Of the 20 patients, 17 patients (85.0%) underwent concomitant extra-anatomical supra-aortic bypass. Postoperative CT revealed type Ia (n = 2) and type II (n = 3) endoleaks which disappeared on follow-up. The postoperative complications were stroke (n = 2, 10.0%), paraplegia (n = 1, 5.0%), and paraparesis (n = 1, 5.0%). In a very old patient, a blood transfusion was performed from the common iliac artery using the retroperitoneal approach. There were no aorta-related complications such as retrograde type A dissection or distal stent graft-induced new entry.

Conclusions

We treated arch or distal arch thoracic aneurysms by inserting a tube-type stent graft as a scaffold on the peripheral site and placing the Najuta thoracic stent graft on the proximal site. By extending the landing zone to Zone 0 and using a low radial force, which is a feature of the Najuta thoracic stent graft system, postoperative bird-beak and aorta-related complications were avoided. The treatment of arch and distal arch aortic aneurysms using the Najuta thoracic stent graft system showed acceptable perioperative and short-term clinical outcomes. Thoracic endovascular aortic repair using the Najuta thoracic stent graft system may be a potential treatment option for arch and distal arch aortic aneurysms, warranting further studies.

Prediction of bird-beak configuration in thoracic endovascular aortic repair preoperatively using patient-specific finite element simulations

Objectives

Formation of bird-beak configuration in thoracic endovascular aortic repair (TEVAR) has been shown to be correlated with the risk of complications such as type Ia endoleaks, stent graft migration, and collapse. The aim of this study was to use patient-specific computational simulations of TEVAR to predict the formation of bird-beak configuration preoperatively.

Methods

Patient-specific TEVAR computational simulations are developed using a retrospective cohort of patients treated for thoracic aortic aneurysm. The preoperative computed tomography images were segmented to develop three-dimensional geometry of the thoracic aorta. These geometries were used in finite element simulations of stent graft deployment during TEVAR. Simulated results were compared against the postoperative computed tomography images to assess the accuracy of simulations in predicting the proximal position of a deployed stent graft and presence of bird-beak. In cases with a bird-beak configuration, the length and angle of the bird-beak were measured and compared between the simulated and postoperative results.

Results

Twelve TEVAR patient cases were simulated. Computational simulations were able to accurately predict whether the proximal stent graft was fully apposed, proximal bare stents were protruded, or bird-beak configuration was present. In three cases with bird-beak configuration, simulations predicted the length and angle of the bird-beak with less than 10% and 24% error, respectively. Other factors such as a small aortic arch angle, small oversizing value, and landing zones close to the arch apex may have played a role in formation of bird-beak in these patients.

Conclusions

Computational simulations of TEVAR accurately predicted the proximal position of a deployed stent graft and the presence of bird-beak preoperatively. The computational models were able to predict the length and angle of bird-beak configurations with good accuracy. These simulations can provide insight into the surgical planning process with the goal of minimizing bird-beak occurrence.

The efficacy and safety of Gore conformable thoracic stent graft and Valiant Captivia thoracic stent graft for acute type B aortic dissection

BACKGROUND

To evaluate the safety and efficacy of the conformable thoracic aortic endograft (Conformable TAG Thoracic Endoprosthesis [CTAG]; W. L. Gore & Associates, Flagstaff, Ariz) and Valiant Captivia thoracic stent graft (Medtronic Inc., Santa Rosa, CA) for acute type B aortic dissection (TBAD).

METHODS

The early and mid-term outcomes were analyzed for 413 patients undergoing TEVAR using conformable TAG thoracic endoprosthesis and Valiant Captivia thoracic stent graft for acute TBAD. 100 propensity-matched pairs of patients were generated, including 100 patients in the CTAG group and 200 patients in the Valiant Captivia group.

RESULTS

Operative mortality were 2.33% (3 of 129) in the CTAG group and 1.76% (5 of 284) in the Valiant Captivia group. The median follow-up was 41.67 (26.00-60.67) months. No significant difference in mortality (9 [7.00%] vs. 36 [12.68%], P = 0.95) or re-intervention rate (3 [2.33%] vs. 20 [7.04%], P = 0.29) was observed between two groups. CTAG group have a lower incidence rate of distal stent graft-induced new entry tear than Valiant Captivia group (2.33% vs. 9.86%, P = 0.045). Lower incidence of type Ia endoleak was identified in the CTAG group (2.22%) than the Valiant Captivia group (14.41%) in patients with type III arch (P = 0.039).

CONCLUSIONS

Both Valiant Captivia thoracic stent graft and CTAG thoracic endoprosthesis can be safely performed for acute TBAD with low operative mortality, favorable mid-term survival and freedom from reintervention. CTAG thoracic endoprosthesis had fewer dSINE even with larger oversizing and potentially suitable for type III arch with fewer type Ia endoleaks.

Effectiveness and Minimal-Invasiveness of Zone 0 Landing Thoracic Endovascular Aortic Repair Using Branched Endograft

Background: Zone 0 landing thoracic endovascular aortic repair (TEVAR) for the treatment of aortic arch diseases has become a topic of interest. This study aimed to verify whether branced TEVAR (bTEVAR) is an effective and a more minimally invasive treatment by comparing the outcomes of bTEVAR and hybrid TEVAR (hTEVAR) in landing zone 0. Methods: This retrospective, single-center, observational cohort study included 54 patients (bTEVAR, n = 25; hTEVAR, n = 29; median age, 78 years; median follow-up period, 5.4 years) from October 2012 to June 2018. The logistic Euro-SCORE was significantly higher in the bTEVAR group than in the hTEVAR group (38% vs. 21%, p < 0.001). Results: There was no significant difference the in-hospital mortality between the bTEVAR and hTEVAR groups (0% vs. 3.4%, p = 1.00). The operative time (220 vs. 279 min, p < 0.001) and length of hospital stay (12 vs. 17 days, p = 0.013) were significantly shorter in the bTEVAR group than in the hTEVAR group. The 7-year free rates of aorta-related deaths (bTEVAR [95.5%] vs. hTEVAR [86.9%], Log-rankp = 0.390) and aortic reintervention (bTEVAR [86.3%] vs. hTEVAR [86.9%], Log-rankp = 0.638) were not significantly different. Conclusions: The early and mid-term outcomes in both groups were satisfactory. bTEVAR might be superior to hTEVAR in that it is less invasive. Therefore, bTEVAR may be considered an effective and a more minimally invasive treatment for high-risk patients.

Comprehensive review of hybrid aortic arch repair with focus on zone 0 TEVAR and our institutional experience

Even with increasing operator experience and a better understanding of the disease and the operation, intervention for aortic arch pathologies continues to struggle with relatively higher mortality, reintervention, and neurologic complications. The hybrid aortic arch repair was introduced to simplify the procedure and improve the outcome. With recent industry-driven advances, hybrid repairs are not only offered to poor surgical candidates but have become mainstream. This review discusses the evolution of hybrid repair, terminology pertinent to this technique, and results. In addition, we aim to provide a pervasive review of hybrid aortic arch repairs with reference to relevant literature for a detailed understanding. We have also discussed our institutional experience with hybrid repairs.

Surgical Repair of Two Kinds of Type A Aortic Dissection After Thoracic Endovascular Aortic Repair

Background

Retrograde dissection is now recognized as an important complication following thoracic endovascular aortic repair (TEVAR). The purpose of this study is to describe two different situations of TAAD after TEVAR. We will introduce the surgical methods used to repair TAAD following TEVAR at our center, and evaluate its long-term prognosis.

Methods

Between January 2010 and October 2019, 50 patients who had previously received TEVAR treatment for TBAD were admitted to our center for repair of a type A aortic dissection. According to the patients’ CT angiographies and intra-operative findings, we identified two distinct groups: a retrograde group (stent-induced new aortic injury, with retrograde extension involving the ascending aorta) and an antegrade group (entry tear located in the aortic root, ascending aorta or the aortic arch, away from the edges of the stent grafts). The options for treatment of the proximal aorta were Bentall procedure (12/50, 24.0%) and ascending aorta replacement (38/50, 76.0%). All patients underwent total arch replacement (TAR) and frozen elephant trunk (FET) implantation. Survival over the follow-up period was evaluated with the Kaplan–Meier survival curve and the log-rank test.

Results

The median interval time from prior TEVAR to reoperation was 187 days (IQR: 30.0, 1375.0 days). 18.0% of TAAD after TEVAR did not have any obvious symptoms at the time of diagnosis, most of which were found on routine follow-up imaging. The patients in the retrograde group were younger than those in the antegrade group (44.0 ± 9.4 vs. 51.4 ± 10.5 years, P = 0.012). No significant differences in the incidence of post-operative complications or mortality were noted between the two groups. The mean follow-up time was 3 years. No late death or complications occurred after one year following surgery upon follow-up. The asymptomatic survival rate one year after surgery was 90.0%.

Conclusion

The TAR and FET technique was feasible and effective for complicated TAAD after TEVAR. The surgical success rate and long-term prognosis of patients undergoing the timely operation are satisfactory.

Effectiveness of Proximal Landing Zones 0, 1, and 2 Hybrid Thoracic Endovascular Aortic Repair: A Single Centre 12 Year Experience

OBJECTIVE

Hybrid thoracic endovascular aortic repair (TEVAR) is being accepted increasingly as a first line treatment for arch repair at the present authors' institution. This study aimed to clarify the effectiveness of zones 0, 1, and 2 landing hybrid TEVAR.

METHODS

This was a retrospective single centre case series. From April 2008 to March 2020, 348 patients (median age 72 years; interquartile range [IQR] 65, 77 years) were enrolled, with a median follow up period of 5.6 years (IQR 2.6, 8.7 years). The procedures included zone 0 in 135 patients (38.8%), zone 1 in 82 patients (23.6%), and zone 2 proximal landing zone (LZ) hybrid TEVAR in 131 patients (37.6%). The pathologies consisted of dissecting aortic aneurysms in 123 (35.3%) patients. Emergency procedures were performed in 39 (11.2%) patients.

RESULTS

The 30 day mortality (n = 2, 0.6%) and hospital deaths (n = 6, 1.7%) were registered. The stroke rate was 1.1% (n = 4), while early and late endoleak rates were 4.8% (n = 17) and 1.7% (n = 6), respectively. Type 1a endoleak and retrograde type A dissection occurred in seven (2.0%) and three (0.9%) patients, respectively. The cumulative survival, freedom from aorta related deaths, and freedom from aortic events in 10 years were 75.0%, 97.2%, and 84.1%, respectively. The freedom from aortic events in each landing zone in 10 years was 82.3%, 81.4%, and 87.9% for zones 0, 1, and 2, respectively. The 10 year survival rates were 82.5% and 73.6%; the 10 year aorta related death free rates were 94.9% and 98.6%, and the 10 year aortic event free rates were 82.3% and 85.5% in the zone 0 and zone 1 and 2 TEVAR, respectively.

CONCLUSION

Satisfactory early and long term results of hybrid arch repair at zones 0, 1, and 2 were achieved. To avoid complications and aortic events, the treatment strategy of hybrid arch repair for aortic arch pathologies should be tailored using accurate pre-operative assessment of the ascending aorta and the aortic arch.

Comparison of the Outcomes of Total Endovascular Aortic Arch Repair Between Branched Endograft and Chimney Endograft Technique in Zone 0 Landing

PURPOSE

Zone 0 landing in thoracic endovascular aortic repair (TEVAR) has recently gained increasing attention for the treatment of high-risk patients. The aim of this study was to compare the outcomes of total endovascular aortic arch repair between branched TEVAR (bTEVAR) and chimney TEVAR (cTEVAR) in the landing zone (LZ) 0.

MATERIALS AND METHODS

This was a single-center, retrospective, and observational cohort study. From January 2010 to March 2020, 40 patients (bTEVAR, n=25; cTEVAR, n=15; median age: 79 years) were enrolled in this study, with a median follow-up period of 4.1 years. These patients were considered unsuitable for open surgical treatment.

RESULTS

All procedures were successful and no cases of conversion to open repair were noted during the 30-day postoperative period. The 30-day mortality was 2.5% (n=1; bTEVAR [0 of 25, 0%] vs cTEVAR [1 of 15, 6.7%]; p=0.375), the perioperative stroke rate was 10.0% (n=4; bTEVAR [4 of 25, 16.0%] vs cTEVAR [0 of 15, 0%], p=0.278), and type 1a endoleak rate was 15.0% (n=6; bTEVAR [0 of 25, 0%] vs cTEVAR [6 of 15, 40.0%], p=0.001). The risk factor for stroke was atheroma grade of ≥2 in the brachiocephalic artery (p<0.001). The risk factor for type 1a endoleak was cTEVAR (p=0.001). The 8-year survival rate was 49.9%. The aorta-related death-free rate and aortic event-free rate at 8 years were 94.4% (bTEVAR: 95.5% vs cTEVAR: 93.3%, p=0.504) and 60.7% (bTEVAR: 70.7% vs cTEVAR: 40.0%, p=0.048), respectively.

CONCLUSIONS

Total endovascular aortic arch repair using bTEVAR and cTEVAR is feasible for the treatment of aortic arch diseases in high-risk patients who are unsuitable for open surgery. However, as the rate of stroke is high, strict preoperative evaluation to prevent stroke is needed. No rupture of the aneurysm was observed in cTEVAR, but patients should be selected carefully because of the high incidence of type 1a endoleak.

Long-term results of hybrid aortic arch repair using landing zone 0: a single-centre study

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) has been gradually extended to the aortic arch region, with improved results. However, the rates of strokes and endoleaks in a hybrid TEVAR remain high. The goal of this study was to clarify the effectiveness of a hybrid TEVAR with a zone 0 landing using our treatment strategy.

METHODS

From April 2008 to March 2020, a total of 102 patients were enrolled in this study, with a median follow-up period of 3.2 years. The procedures included total debranching TEVAR with graft replacement of the ascending aorta in 62 patients, total debranching TEVAR with ascending aorta banding in 19 patients and total debranching TEVAR without ascending aorta banding in 21 patients.

RESULTS

Thirty-day mortality and hospital deaths were 1.0% (n = 1) and 3.9% (n = 4), respectively. The rates of aortic complications and endoleaks during the first 30 days postoperatively were 8.8% (n = 9) and 4.9% (n = 5), respectively. There was no type 1a endoleak, whereas retrograde type A dissection occurred in 2 (2.0%) patients. The rate of late aortic events was 3.9% (n = 4); there were no late endoleaks or aneurysm ruptures. The 10-year survival rate was 73.7% [95% confidence interval (CI) 60.3-83.8%]. The 10-year rates of aorta-related deaths and aortic events when performing a competitive-risk analysis were 29.4% (95% CI 16.3-42.5%) and 7.2 (95% CI 23.0-51.4%), respectively.

CONCLUSIONS

Satisfactory early and long-term results of a hybrid TEVAR with a zone 0 landing were achieved using our treatment strategy. When performing hybrid TEVAR in zone 0, postoperative aortic events may be reduced by accurate preoperative assessment of the ascending aorta.

Association between aortic arch angulation and bird-beak configuration after thoracic aortic stent graft repair of type B aortic dissection

OBJECTIVES

The goal of this study was to investigate factors favouring the bird-beak configuration after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection.

METHODS

We retrospectively analysed 76 patients with type B aortic dissection who underwent landing zone 1 and 2 TEVAR from December 2015 to January 2018. Preoperative aortic arch geometry (aortic arch length, maximal diameter and angulation), stent graft details and operative details were evaluated. A bird-beak configuration was defined as a ≥5-mm gap between the proximal end of the stent and the aortic wall of the lesser curvature.

RESULTS

Patients were stratified into those with (n = 46) and without (n = 30) a bird-beak configuration. The baseline demographics, dissection chronicity, clinical features and implanted devices were largely similar between the 2 groups. No significant difference was observed in the arch length or maximal arch diameter. However, the mean aortic arch angulation was greater in patients with than without a bird-beak configuration (61.4° vs 51.3°; P < 0.001). No influence of either the stent graft brand or the proximal stent graft type was observed. The multivariable analysis showed that the aortic arch angulation was an independent risk factor for a bird-beak configuration (odds ratio 1.15, 95% confidence interval 1.07-1.24; P < 0.001). A cut-off angle of 59.15° was predictive of a bird-beak configuration (sensitivity 59%; specificity 77%).

CONCLUSIONS

The preoperative aortic arch angulation was an independent predictor of a postoperative bird-beak configuration in patients with type B aortic dissection who underwent TEVAR that involved the aortic arch. An angle of >59.15° may imply a relatively hostile anatomy with a higher risk of a bird-beak configuration.

Long-term outcomes of the conformable TAG thoracic endoprosthesis in a prospective multicenter trial

BACKGROUND

The Gore conformable TAG thoracic endoprosthesis (CTAG) was engineered to enhance conformability in the thoracic aorta and has demonstrated greater deployment accuracy and wall apposition than the original TAG device. The Food and Drug Administration approved the CTAG in 2011 based on the 1-year results of the pivotal trial for the CTAG device. In the present report, we have documented the outcomes for those patients through 5 years.

METHODS

The CTAG aneurysm study was a prospective, multicenter trial that assessed the safety and effectiveness of the CTAG device as treatment of descending thoracic aortic aneurysms. Follow-up imaging assessments consisted of radiographs and computed tomography at annual intervals through 5 years. A core imaging laboratory was used to assess the aneurysm size, device integrity, and endoleaks.

RESULTS

A total of 66 patients were enrolled (51 pivotal arm patients and 15 continued access patients) from October 2009 through September 2011. The baseline characteristics, procedural characteristics, and outcomes through 2 years were reported previously. Through 5 years, five patients (7.6%) had required device-related reintervention (one type Ia endoleak or contained rupture of the descending thoracic aorta, one type Ib endoleak, two indeterminate endoleaks, and one thoracic aortic pseudoaneurysm). Four patients (6.1%) had died of aneurysm-related causes, with one death occurring within 30 days of the index procedure. A total of 24 patients (36.3%) had died during the 5-year study period. Seven patients (10.6%) had experienced stroke or transient ischemic attack through 5 years, with one early stroke (postoperative day 28). Prosthesis or intercomponent migration was observed in six patients (9.1%) through 5 years; however, no patient had developed a type III junctional endoleak. No stent-graft fracture or compression was observed through 5 years. At 5 years, 14 patients (50.0%) showed sac regression, 5 (17.9%) showed sac expansion, and 9 (32.1%) showed sac stability using on a 5-mm threshold for change.

CONCLUSIONS

Thoracic endovascular aortic repair with the CTAG device was associated with low rates of aneurysm-related mortality and reintervention through 5 years. Proximal endoleak was rare, and most patients showed sac regression or stability at 5 years after the initial thoracic endovascular aortic repair.

Multiaxial pulsatile dynamics of the thoracic aorta and impact of thoracic endovascular repair

•

Altered motion of the thoracic aorta after thoracic endovascular aortic repair.

•

Geometric analysis with cardiac-gated computed tomography and computer modeling.

•

Decreased motion of the stented aorta and increased motion above the stented aorta.

•

Longitudinal curvature and diametric deformation affected by presence of endograft.

Purpose

The thoracic aorta is a highly mobile organ whose dynamics are altered by thoracic endovascular aorta repair (TEVAR). The aim of this study was to quantify cardiac pulsatility-induced multi-axial deformation of the thoracic aorta before and after descending aortic TEVAR.

Methods

Eleven TEVAR patients (8 males and 3 females, age 57–89) underwent retrospective cardiac-gated CT angiography before and after TEVAR. 3D geometric models of the thoracic aorta were constructed, and lumen centerlines, inner and outer surface curves, and cross-sections were extracted to measure aortic arclength, centerline, inner surface, and outer surface longitudinal curvatures, as well as cross-sectional effective diameter and eccentricity for the ascending and stented aortic portions.

Results

From pre- to post-TEVAR, arclength deformation was increased at the ascending aorta from 5.9 ± 3.1 % to 8.8 ± 4.4 % (P < 0.05), and decreased at the stented aorta from 7.5 ± 5.1 % to 2.7 ± 2.5 % (P < 0.05). Longitudinal curvature and diametric deformations were reduced at the stented aorta. Centerline curvature, inner surface curvature, and cross-sectional eccentricity deformations were increased at the distal ascending aorta.

Conclusions

Deformations were reduced in the stented thoracic aorta after TEVAR, but increased in the ascending aorta near the aortic arch, possibly as a compensatory mechanism to maintain overall thoracic compliance in the presence of reduced deformation in the stiffened stented aorta.

Zone 1 Aortic Arch Hybrid Endovascular Repair with Extra-anatomical Bypass: A Meta-analysis

BACKGROUND

The aim of this meta-analysis is to determine the morbidity and mortality outcomes of adult patients with aortic arch disease managed with extra-anatomical bypass avoiding median sternotomy and cardiopulmonary bypass, with simultaneous or staged hybrid zone 1 endovascular aortic repair.

METHODS

Systematic literature searches of the MEDLINE, EMBASE, and Cochrane databases were carried out to identify relevant studies on zone 1 hybrid arch repair. Extracted data were analyzed by random effects models. Primary outcomes included 30-day or in-hospital mortality. Longitudinal survival was analyzed up to 7 years from date of operation. Secondary outcomes included in-hospital morbidity, as well as late endoleak and reintervention.

RESULTS

Twenty studies incorporating 348 patients were included. In-hospital or 30-day mortality was 10.1% (95% confidence interval, 6.7-14.9%). Overall operative technical success was 89.8% (83.7-93.8%). Early type 1 endoleak rate was 14.0% (7.4-24.7%). Stroke prevalence was 9.5% (6.1-14.3%). Spinal cord paraplegia prevalence was 3.8% (1.9-7.6%). Retrograde aortic dissection prevalence was 4.1% (1.5-10.6%). Survival at 1 year postoperatively was 77.2% (66.1-85.4%). Survival at 3 years postoperatively was 73.7% (59.2-84.4%). Survival beyond 4 years postoperatively (range 58-80 months) was 65.9% (53.6-76.4%). Late type 1 endoleak prevalence was 11.8% (5.5-23.7%). Overall rate of reintervention was 11.6% (6.4-20.1%).

CONCLUSIONS

Zone 1 hybrid repair has evidence for satisfactory short- and long-term morbidity/mortality outcomes and may be considered as an alternative approach to aortic arch disease.

The surgical management of type IA endoleak after thoracic endovascular aortic repair

OBJECTIVES

Our goal was to investigate the surgical strategy for type Ia endoleak after thoracic endovascular aortic repair (TEVAR) by reporting our experiences.

METHODS

From November 2012 to September 2019, a total of 23 patients received surgical management for type Ia endoleak after TEVAR.

RESULTS

The operations included total arch replacement with the frozen elephant trunk technique in 15 patients, direct closure of the endoleak in 2 patients, hybrid aortic arch repair in 4 patients, arch debranching with TEVAR in 1 patient and left common carotid artery to left subclavian artery bypass with TEVAR in 1 patient. Among 21 patients with cardiopulmonary bypass (CPB), the mean CPB and aortic cross-clamp times were 146.7 ± 42.2 and 81.0 ± 43.3 min, respectively. The selective cerebral perfusion time was 18.8 ± 8.2 min in 17 patients with hypothermic circulatory arrest. The in-hospital mortality was 8.7% (2/23). Type Ia endoleak was sealed successfully after surgery in 95.5% (21/22) of patients. The follow-up data were available for all 21 survivors. The median follow-up period was 18 months (range 1-84 months). During the follow-up period, a total of 8 patients died or had aortic events, including 5 deaths and 6 aortic events.

CONCLUSIONS

Different surgical strategies could be selected to treat patients with type Ia endoleak after TEVAR, with acceptable early and late outcomes.

Numerical modeling and simulations of type B aortic dissection treated by stent-grafts with different oversizing ratios

Retrograde type A dissection after thoracic endovascular aortic repair has been a major drawback of endovascular treatment. This study investigated the biomechanical mechanism of stent-graft-induced new lesions after implantation and analyzed the relationship between radial force and spring-back force of the stent-graft when it was implanted virtually under different oversizing ratios. Based on the computed tomography angiography images, a three-dimensional geometric model of a patient-specific aortic dissection was established. The stent was designed in CAD software and the stent-graft implantation procedure under different oversizing ratios was simulated in the finite element analysis software. Implantation simulations were performed six times for each stent-graft model under 0%, 3%, 6%, 9%, 12%, and 15% oversizing ratios and the peak stress of the aorta was compared among groups. It was observed that the peak stress of the aorta was located where the proximal bare stent interacted with aortic wall and its value was increased by 62.2% from 0% to 15% oversizing ratio. The conclusions are reached that the long-term higher stress in the aortic wall may lead to the emergence of new lesions in these areas, and the radial force plays a key role in the formation of a new entry in the real aorta model.

Prosthetic Graft Dilation at the Aortic Arch in the Era of Hybrid Aortic Surgery

Objective: This study aims to evaluate the chronological size changes of the prosthetic graft in the aortic arch, which is used as a landing zone for a subsequent stent grafting in hybrid aortic surgery.

Materials and Methods: Eighty-five patients who underwent total aortic arch replacement followed by computed tomography follow-up for at least 30 months after the surgery were included in the study.

Results: Prosthetic grafts used were Hemashield (Maquet, Rastatt, Germany), J-Graft (Japan Lifeline Inc., Tokyo, Japan) and Triplex (Terumo, Tokyo, Japan). There was an initial increase in diameter compared to package size after implantation (Hemashield, 1.04±0.035 vs. J-Graft, 1.06±0.027 vs. Triplex, 1.04±0.023, p=0.13). Significant difference in graft dilation ratio was observed in Triplex (1.18±0.062) at long-term compared to Hemashield (1.07±0.052, p<0.001) and J-Graft (1.10±0.071, p<0.001). Multivariate analysis showed that age (r=0.002; 95% confidence interval [CI], 0.0001–0.0037; p=0.035), knitted-type prosthesis (r=0.089; 95% CI, 0.0610–0.1163; p<0.0001), and prevalence of cerebral vascular disease (r=0.038; 95% CI, 0.0030–0.0732; p=0.034) were independently associated with graft dilation after surgery.

Conclusion: Prosthetic graft selection and appropriate sizing of the stent graft should be considered for each individual undergoing hybrid aortic surgery to maintain sufficient oversizing of the stent graft.

Determining the Optimal Proximal Landing Zone for TEVAR in the Aortic Arch: Comparing the Occurrence of the Bird-Beak Phenomenon in Zone 0 vs Zones 1 and 2

Purpose: To identify the optimal proximal landing zone for thoracic aortic endovascular repair (TEVAR) of aortic arch pathologies so as to avoid the bird-beak phenomenon that leads to type Ia endoleak. Materials and Methods: A retrospective single-center review was conducted of 164 patients (mean age 70.3±10.8 years, range 29–93; 127 men) who underwent repairs of the aortic arch using hybrid TEVAR from April 2008 to March 2017. The patients were divided into 2 groups according to the proximal landing zone: 43 zone 0 patients (26.2%) had total debranching TEVAR (n=18) or total endovascular aortic repair (n=25) while 121 patients (73.8%) had TEVAR landing in zones 1 (n=41) or 2 (n=80). Bird-beak configurations, endoleaks, and stent migrations were assessed on the postoperative and latest computed tomography angiography (CTA) scans. Overall survival and freedom from the bird-beak configuration, aorta-related death, and aortic events were estimated using the Kaplan-Meier method. Hazard ratios (HR) were calculated with the 95% confidence interval (CI). Results: All procedures were successful, without any 30-day mortality. There were 3 early complications (1.8%; all strokes) and 10 early endoleaks (6.1%; no type Ia). On the first postoperative CTA, 42 patients (25.6%) had a bird-beak configuration. The zone 0 patients had significantly fewer (p<0.001), shorter (p<0.004), and less angulated (p<0.001) bird-beak configurations than in zones 1–2. The mean follow-up period was 4.2 years (range 0.5–8.8). There were 18 late deaths (11.0%); only one was related to the aorta (rupture due to a type Ib endoleak in a zone 0 patient). The 5-year freedom from aorta-related death was not significantly different between groups (zone 0: 96.9% vs zones 1–2: 100%, p=0.080). On the latest CTA, 51 (31.0%) patients had a bird-beak configuration; of those, 22 (13.4%) showed >3-mm progression. The freedom from bird-beak configuration estimate was significantly higher in the zone 0 group (95.4%) vs zones 1–2 (57.8%; HR 0.10, 95% CI 0.02 to 0.31, p<0.001). There were 9 late endoleaks (4 type Ia; none in the zone 0 group). The rate of stent-graft migration was significantly lower in the zone 0 group (2.3% vs 14.1% in zones 1–2, p=0.035). Conclusion: Early and most late results in zone 0 TEVAR were equal to those in zones 1 and 2; however, there were no late type Ia endoleaks and fewer bird-beak configurations associated with zone 0 TEVAR, which suggests that zone 0 landing is advantageous for preventing these complications.

Repair of Type Ia Endoleaks Involving the Distal Arch Using Left Subclavian Artery-Left Common Carotid Artery Transposition with a Stented Elephant Trunk

BACKGROUND

Type Ia endoleaks are common after thoracic endovascular aortic repair (TEVAR). However, the repair of type Ia endoleaks involving the distal arch is challenging because of the presence of the interventional endografts, potential damage to the aortic arch vessels, and the location and size of the aneurysmal body. We retrospectively reviewed our experience of the surgical treatment of type Ia endoleaks with distal arch involvement using left subclavian artery (LSCA)-left common carotid artery (LCCA) transposition with a stented elephant trunk.

METHODS

Sixteen patients (male = 16; mean age, 47 ± 9 years, range 31-63 years) with type Ia endoleaks involving the distal arch underwent LSCA-LCCA transposition with a stented elephant trunk from July 2010 to July 2018. TEVAR failure occurred in 12 patients, re-TEVAR was performed in two patients, hybrid aortic arch repair in one patient, and the chimney technique in one patient.

RESULTS

There were no in-hospital deaths. Fourteen patients required mechanical ventilation for <24 h and one for <48 h. One patient required reintubation after mechanical ventilation for 19 h and continuous renal replacement therapy because of renal failure. One patient received pericardial drainage, and recurrent laryngeal nerve injury occurred in one patient. Three patients died during follow-up.

CONCLUSIONS

The LSCA-LCCA transposition with a stented elephant trunk can produce satisfactory results in patients with a type Ia endoleak involving the distal arch. Using this technique, it is possible to exclude the aneurysm sac distal to the LCCA origin and seclude the failed interventional endograft. These encouraging outcomes suggested that this technique could be a suitable surgical treatment for this type of lesion.

Automated Quantification of Diseased Thoracic Aortic Longitudinal Centerline and Surface Curvatures

Precise description of vascular morphometry is crucial to support medical device manufacturers and clinicians for improving device development and interventional outcomes. A compact and intuitive method is presented to automatically characterize the surface geometry of tubular anatomic structures and quantify surface curvatures starting from generic stereolithographic (STL) surfaces. The method was validated with software phantoms and used to quantify the longitudinal surface curvatures of 37 human thoracic aortas with aneurysm or dissection. The quantification of surface curvatures showed good agreement with analytic solutions from the software phantoms, and demonstrated better agreement as compared to estimation methods using only centerline geometry and cross-sectional radii. For the human thoracic aortas, longitudinal inner surface curvature was significantly higher than centerline curvature (0.33 ± 0.06 versus 0.16 ± 0.02 cm−1 for mean; 1.38 ± 0.48 versus 0.45 ± 0.11 cm−1 for peak; both p &lt; 0.001). These findings show the importance of quantifying surface curvatures in order to better describe the geometry and biomechanical behavior of the thoracic aorta, which can assist in treatment planning and supplying device manufactures with more precise boundary conditions for mechanical evaluation.

Impact of the Bird-Beak Configuration on Postoperative Outcome After Thoracic Endovascular Aortic Repair: A Meta-analysis

Purpose: To investigate the association between the bird-beak configuration (BBC), a wedge-shaped gap between the undersurface of a thoracic endograft and the lesser curvature of the arch after thoracic endovascular aortic repair (TEVAR), and postoperative outcome after TEVAR. Methods: The study was performed according to the PRISMA guidelines. The PubMed, EMBASE, and Cochrane databases were searched to identify all case series reporting BBC after TEVAR between 2006 and April 2018. Data analysis was performed considering the difference in the risk of complications for presence vs absence of BBC. After screening 1633 articles, 21 studies were identified that matched the selection criteria; 12 of these reported detailed information to investigate the postoperative outcome using proportion meta-analysis with a random effects model. The pooled risk difference is reported with the 95% confidence interval (CI). Heterogeneity of the included studies was assessed with the I2 statistic (low 25%, medium 50%, high 75%). Results: Complications occurred within a range of 0 to 72 months in 14.7% (95% CI 7.4% to 27.3%) of patients with BBC and in 6.3% (95% CI 2.5% to 15.4%) of patients without BBC. A cumulative incidence could not be assessed. The summary risk difference was 11.1% (95% CI −0.1% to 22.3%, p=0.052). There was significant heterogeneity ( I2=85.6%). The Egger test did not show evidence of publication bias (p=0.975). When specifically considering type Ia endoleak and endograft migration, the risk difference between BBC and non-BBC patients was 8.2% (95% CI 0.3% to 16.1%, p=0.042; I2=69.0%). The specific risk difference for endograft collapse/infolding and thrombosis was 3.7% (95% CI −3.5% to 11.1%, p=0.308; I2=10.2%). Conclusion: At present the literature does not provide statistical evidence to establish an overall prognostic value of the BBC. Nevertheless, the BBC appears to be associated with a high risk of type Ia endoleak and endograft migration, which warrants specific and long-term surveillance. Clinically relevant values for BBC grading should be established to perhaps define indications for preemptive treatment based on the presence of BBC only.