Stent Graft Length Research Articles

The results of thoracic endovascular aortic repair for high-risk type B aortic dissection

Overview: Evaluating the efficacy of endovascular intervention in treatment of high-risk type B aortic dissection Methods: Review a series case of high-risk type B aortic dissection cases treated with endovascular intervention at Cho Ray Hospital from January 2020 to December 2022. Results: The study included a total of 30 patients with high-risk type B aortic dissection who underwent endovascular intervention meeting all sampling criteria. The average age was 53 years (26-73 years), with males accounting for 86.7%. The most common risk factor was hypertension (86.7%). Pain was the primary reason for hospital admission, with chest pain being the most frequent (80%). The most prevalent high-risk factors were false lumen diameter > 22mm (66.7%), followed by aortic diameter > 40mm (36.7%), and entry tear diameter > 10mm (33.3%). Regarding intervention characteristics, the average stent graft length was 207.3mm, with proximal landing zones predominantly in zone 1 (23.3%), zone 2 (40%), and zone 3 (36.7%). Twenty-nine patients were continuously monitored for an average of 4.3 months, with a complication rate of 10% including endoleak type Ia (6.9%) and retrograde dissection (3.4%). Aortic remodeling was evidenced by a significant reduction in false lumen size (p<0.001) Conclusion: Follow-up results show a low rate of complications and a high rate of aortic reconstruction post-intervention.

Changes of vascular stiffness and central blood pressure after endovascular aneurysm repair in patients with hypertension. Results of one-year follow-up

Aim. To assess the changes of arterial stiffness, central blood pressure (CBP), and determine the factors potentially influencing them in patients with descending thoracic and abdominal aortic aneurysm, in combination with hypertension, one year after endovascular aneurysm repair ((T)EVAR).Material and methods. Patients ≥18 years of age without clinically significant cardiac arrhythmias were included. Before surgery and a year later, we determined peripheral blood pressure, heart rate (HR), CBP, augmentation index (AIx), pressure at the point of maximum rise of the direct pulse wave (PT1h), time to return of the reflected pressure wave (Tr) and carotid femoral pulse wave velocity (cfPWV).Results. Fifty patients were included (mean age, 68±9 years; 41 men; 16 with descending thoracic aortic aneurysm, 34 with abdominal aortic aneurysm), 23 patients were reexamined. After (T)EVAR, an increase in cfPWV (+2,6 m/s, p<0,001), PT1h (+5 mm Hg, p=0,026), peripheral pulse pressure (+7 mm Hg, p=0,039), heart rate (+5 beats/min, p=0,025). The CBP and AIx values have not changed. The dependence of Tr decrease on the stent-graft length (β=0,42) and the decrease in heart rate (β=-0,52) was found. During the year, 6 cardiovascular events were registered.Conclusion. Graft implantation is accompanied by an increase in cfPWV, regardless of aneurysm location. An increase in PT1h one year after (T)EVAR may reflect a decrease in aortic distensibility and worsening damping function. No changes of CBP and AIx is probably explained by reflected wave characteristics after surgery. Predictors of Tr are — increase in heart rate and implantation of longer stent grafts.

Observational study of endoluminal mural thrombotic apposition in popliteal artery aneurysm stenting and its relationship with stent-graft geometrical features.

The development of intrastent thrombosis is one of the mechanisms related to medium- to long-term failure of endovascular treatment of popliteal artery aneurysm. The present study aims to investigate possible links between the development of endoluminal mural thrombotic apposition in the stented zone (EMTS) with both geometrical features of stent-graft(s) and time of follow-up. Patients with popliteal artery aneurysm who underwent endovascular treatment were recruited during the follow-up period. Segmentation of computed tomography angiography scan was performed to detect femoropopliteal artery lumen, leg bones, EMTS, and stent-graft(s). The following parameters were assessed: number, diameter, and length of stent-graft(s); and shape, volume, and length of thrombotic apposition within the stent(s). The spiral shape of the thrombotic apposition was evaluated as well. Eighteen male patients were recruited in the study. EMTS was observed in 13 of them (72%) during the follow-up analysis. An average of 1.8 ± 0.79 stents-grafts were implanted per patient with a median diameter and length of 6.2 (1.9) mm and 125 (50) mm, respectively. The percentage of the stent length where EMTS was present was 42.1 on average (interquartile range: 42.4%) with a mean volume of 206.8 mm3. A positive correlation was found between the length and volume of EMTS (R-squared = 0.71, p < 0.01). Moreover, EMTS had a helical shape in 8/13 patients, with 4/5 with counterclockwise rotation with stent-grafts in the left leg and 3/3 with clockwise direction treated in the right leg. A higher frequency of EMTS was observed in patients with longer follow-up and higher risk factors, as well. EMTS is observed in most of the patients under analysis, especially in those with medium- to long-term follow-up. The pattern of such EMTS follows a helical shape having a direction that depends on which leg, right or left, is treated. Our results suggest a close surveillance of popliteal aneurysm stenting by follow-up examinations to control the onset and progression of EMTS.

Is the Mid-Term Patency Rate of Small-Diameter Viabahn Stent-Grafts in Peripheral Artery Disease Related to Their Length? A Systematic Review.

Small-diameter endografts can be used for the treatment of the peripheral vascular disease, but the patency rate during the follow-up is still under debate. With this review, we aimed at analyzing the mid-term patency of small-diameter Viabahn stent-grafts and investigating the relationship between patency and the length of the graft. We performed a review of articles published until September 2020 and reporting use of ≤7-mm-diameter Viabahn stent-grafts in diseased peripheral arteries. Data on study type, demographic, lesion length, stent-graft diameter, length, and patency (1-year, 3-year, 5-year primary patency, primary-assisted patency, and secondary patency), follow-up, endoleak, and re-intervention rates were extracted and analyzed. A statistical test was applied to identify a correlation between stent-graft length and patency. 16 retrospective and 7 prospective studies reported the outcome of 1613 patients (mean age: 69.6±33.7 years). There was considerable heterogeneity in reporting standards among studies. The diameter of Viabahn stent-grafts ranged 5 to 7mm and the average length was 23.6±12.4cm. Heparin-bonded grafts were used in 46.4% of cases. Mean follow-up time was 26.4±17.6 months. The 1- and 5-year primary patency rate was 75.7% (95% CI, 73.6%-77.8%) and 46.8% (95% CI, 41.0%-52.6%), respectively. The 1- and 5-year primary-assisted patency rate was 80.9% (95% CI, 73.9%-87.8%) and 60.9% (95% CI, 46.4-75.5%), respectively. The 1- and 5-year second-assisted patency was 90.4% (95% CI, 87.4%-93.3%) and 73.7% (95% CI, 64.7%-82.8%), respectively. No correlation between the stent-graft length and patency was found. Small-diameter Viabahn stent-graft implantation represents a safe treatment for patients with peripheral artery disease, and the mid-term patency rate seems not be affected by the length of the graft. The use of small diameter stent-grafts for peripheral vascular disease is an established technique but the patency rate is still under debate. With this review we have investigated the relationship between the mid-term patency and the diameter of the stent-grafts. Afterv having analysed data from 23 published studies including 1613 patients we can conclude that the treatment of the peripheral artery disease with small diameter stent-grafts is safe and the mid-term patency rate seems not be affected by the lenght of the grafts.

A Simplified Computational Workflow for Evaluation of Aortic Hemodynamics After Frozen Elephant Trunk Intervention in Type A Aortic Dissection

This study aimed to predict the hemodynamic performance of frozen elephant trunk (FET) intervention in surgically repaired type A aortic dissection (TAAD) patients through computational simulations of post-operative scenarios. Patient-specific geometries of a single patient were reconstructed from pre- and post-FET intervention computed tomography angiography (CTA) images. The pre-FET geometry was used to create post-FET geometry through anatomical modifications and a simplified finite element simulation to inflate the stented true lumen (TL) segment. Computational fluid dynamics (CFD) simulations were then performed on the virtually created post-FET geometry, and the results were compared with those obtained with the actual post-FET geometry. Various intervention scenarios with different stent-graft (SG) lengths and TL volume expansion were also simulated and compared to study their impacts on hemodynamic performance. A good overall agreement was achieved between the virtual and real post-FET models, with the maximum difference in true and false lumen (FL) pressures along the dissected aorta being 4.2%. Simulation results for the actual intervention revealed high wall shear stress (WSS) and pressure around a distal tear that was found to have expanded on post-FET scan. Extending the SG length dramatically reduced the maximum WSS and pressure around the distal tear. This pilot study demonstrates the feasibility of using the simplified simulation workflow for personalized assessment of aortic hemodynamics following FET intervention in repaired TAAD. Further studies in a large patient cohort are warranted.

Stent Diameter, Not Cephalic Arch Anatomy, Predicts Stent Graft Patency in Cephalic Arch Stenosis

PurposeTo investigate the relationship between anatomic factors and primary patency of brachiocephalic arteriovenous fistulae (AVFs) after stent graft (SG) placement for cephalic arch stenosis (CAS). Materials and MethodsThis retrospective study reviewed all cephalic arch SGs placed in brachiocephalic AVFs in a tertiary academic medical center between 2014 and 2017. Sixty-three patients were included in the study. The mean patient age at the time of SG placement was 62.6 years ± 19, and the mean patient follow-up was 1,994 days ± 353. A cohort of patients (n = 31) who underwent brachiocephalic fistulograms for CAS but only received percutaneous transluminal angioplasty (PTA) was the control group. Patient demographic characteristics, AVF anatomy, SG type, and clinical outcomes were reviewed. The duration of primary cephalic arch patency after SG placement was compared with that after previous PTA. ResultsThe median AVF age at the time of data retrieval was 345 days. The primary patency of CAS after SG placement at 6 months, 12 months, and 3 years was 64%, 49.9%, and 23.5%, respectively. Primary cephalic arch patency was significantly associated with the SG diameter (P = .007) but not with cephalic vein–axillary vein junction anatomy, size of feeding artery, or SG length (P > .05). The primary patency of CAS in patients treated with PTA only (n = 31) at 6 months, 12 months, and 3 years was 61%, 35%, and 0%, respectively, which was significantly lower than that in patients treated with SG placement (P = .01). ConclusionsThis study showed that the primary patency of CAS after SG placement was significantly higher than that of PTA-only treatment. Moreover, primary cephalic arch patency after SG placement was significantly associated with the SG diameter.

Association between aortic coverage and spinal cord ischemia after endovascular repair of type B aortic dissection.

To examine the association between aortic coverage and occurrence of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. Thirty-eight consecutive patients (mean age 52years; 35 men) who underwent TEVAR for type B aortic dissection at our centre were included. Patients were stratified into two groups based on stent graft length (SGL): group I (≤ 200mm; n = 19) and group II (> 200mm; n = 19). All the procedures were performed under strict blood pressure monitoring. Preoperative cerebrospinal fluid (CSF) drain was instituted in two patients. Mean SGLs were 200mm in group I and 277 ± 27mm in group II. The number of segmental arteries covered was significantly different between the two groups (p < 0.001). There was no significant difference in vertebral artery dominance between groups I and II (p = 0.99). One patient in group II, who also had bilateral internal iliac artery occlusion, developed postprocedural neurological deficit referrable to SCI, which resolved completely after institution of CSF drainage. However, the incidence of SCI was not significantly different between group I and group II (p = 0.5). Based on our experience, we recommend longer aortic coverage (beyond 200mm) in type B aortic dissection (TBAD) for better aortic remodelling, provided that the mean arterial pressure of > 90mm Hg is maintained perioperatively to avoid SCI.

Greater Curvature, Centerline or Straightened Centerline Length - Which length is Most Accurate for Preprocedural Planning in Thoracic Endovascular Aortic Repair?

BackgroundAutomated centerline (CL) measurements have been conventionally used for stent-graft length estimation during thoracic endovascular aortic repair (TEVAR). The purpose of this study was to assess the accuracy of greater curvature length (GL), semiautomated CL and straightened centerline length (SCL) for preprocedural planning in TEVAR. MethodsImmediate postprocedural CT Angiographies of 30 patients (22 males, age-49.2 ± 10.1years) who underwent TEVAR between 2015 and 2017 were retrospectively analyzed. CL, GL, SCL and the straightline length(SL) were measured between proximal and distal ends of the stent-graft and results were compared with the true length of the stent-graft (TL). Tortuosity index (TI = CL/SL) was calculated. ResultsGL (17.92 ± 4.78 cm) was the closest in predicting the TL (17.75 ± 4.29 cm) (P = 0.414) overall, as well as in both dissection and aneurysm subgroups (P= 0.9). There was a significant difference between CL (16.67 ± 4.07 cm) and TL (P< 0.0001) as well as between SCL (16.86 ± 4.16 cm) and TL (P= 0.001). These differences were greater in dissection subgroup than in the aneurysm group (P< 0.0001 and P= 0.03 for TL-CL and TL-SCL, respectively). The extent of mismatch between GL or CL and TL did not correlate with tortuosity, but the difference between TL and SCL had a significant positive correlation with tortuosity (r = 0.375, P= 0.04). TL-GL had a negative linear correlation with the stent-graft length (TL) in the dissection group (r = 0.50, P= 0.03). ConclusionsThe greater curvature length predicts the actual total length of the deployed stent-graft more accurately than centerline or straightened centerline lengths. Hence, it should be used in planning for the length of stent-graft required for TEVAR.

Patient-Specific Virtual Stent-Graft Deployment for Type B Aortic Dissection: A Pilot Study of the Impact of Stent-Graft Length.

Thoracic endovascular aortic repair (TEVAR) has been accepted as a standard treatment option for complicated type B aortic dissection. Distal stent-graft-induced new entry (SINE) is recognised as one of the main post-TEVAR complications, which can lead to fatal prognosis. Previous retrospective cohort studies suggested that short stent-graft (SG) length (<165 mm) might correlate with increased risk of distal SINE. However, the influence of SG length on changes in local biomechanical conditions before and after TEVAR is unknown. In this paper, we aim to address this issue using a virtual SG deployment simulation model developed for application in type B aortic dissection. Our model incorporates detailed SG design and hyperelastic behaviour of the aortic wall. By making use of patient-specific geometry reconstructed from pre-TEVAR computed tomography angiography (CTA) scan, our model can predict post-TEVAR SG configuration and wall stress. Virtual SG deployment simulations were performed on a patient who underwent TEVAR with a short SG (158 mm in length), mimicking the actual clinical procedure. Further simulations were carried out on the same patient geometry but with different SG lengths (183 mm and 208 mm) in order to evaluate the effect of SG length on changes in local stress in the treated aorta. Comparisons of simulation results for different SG lengths showed the location of maximum stress varied with the SG length. With the short SG (deployed in the patient), the maximum von Mises stress of 238.9 kPa was found on the intimal flap at the distal landing zone where SINE was identified at 3-month follow-up. Increasing the SG length caused the maximum von Mises stress to move away from the distal landing zone where stress values were reduced by approximately 17% with the medium-length SG and by 60% with the long SG. This pilot study demonstrates the potential of using the virtual SG deployment model as a pre-surgical planning tool to help select the most appropriate SG length for individual patients.

Effect of Vessel Tortuosity on Stress Concentration at the Distal Stent-Vessel Interface: Possible Link With New Entry Formation Through Biomechanical Simulation.

A computational approach is used to investigate potential risk factors for distal stent graft-induced new entry (dSINE) in aortic dissection (AD) patients. Patient-specific simulations were performed based on computed tomography images acquired from six AD patients (three dSINE and three non-dSINE) to analyze the correlation between anatomical characteristics and stress/strain distributions. Sensitivity analysis was carried out using idealized models to independently assess the effect of stent graft length, stent tortuosity and wedge apposition angle at the landing zone on key biomechanical variables. Mismatch of biomechanical properties between the stented and nonstented regions led to high stress at the distal stent graft-vessel interface in all patients, as well as shear strain in the neighboring region, which coincides with the location of tear formation. Stress was observed to increase with the increase of stent tortuosity (from 263 kPa at a tortuosity angle of 50 deg to 313 kPa at 30 deg). It was further amplified by stent graft landing at the inflection point of a curve. Malapposition of the stent graft led to an asymmetrical segment within the aorta, therefore changing the location and magnitude of the maximum von Mises stress substantially (up to +25.9% with a +25 deg change in the distal wedge apposition angle). In conclusion, stent tortuosity and wedge apposition angle serve as important risk predictors for dSINE formation in AD patients.

The zone 2 concept and distal stent graft positioning in TH 2-3 are associated with high rates of secondary aortic interventions in frozen elephant trunk surgery.

The goal of this study was to investigate the association between the localization of the distal anastomosis (zone 2/3), the stent graft length (100-160 mm), the position of the distal end of the hybrid prosthesis and the need for secondary aortic intervention (SAI) in acute and chronic thoracic aortic disease after the frozen elephant trunk procedure. From 2009 through 2020, a total of 232 patients (137 men; mean age, 61.7 ± 13.8 years) were treated with the frozen elephant trunk procedure. The main indications were acute aortic dissection type A (n = 106, 46%), chronic aortic dissection type A (n = 52, 22%) and degenerative thoracic aortic aneurysm (n = 74, 32%). The rate of SAI was significantly higher when we performed a distal anastomosis in zone 2 rather than in zone 3, whereas the rate of SAI was less frequent if the distal positioning of the hybrid prosthesis was below TH 4-5. Combining the zone 2 concept and the short stent graft length (100 mm) was associated with a significantly higher rate of SAIs. Patients with a distal anastomosis in zone 2 were significantly less likely to have a recurrent laryngeal nerve injury (P < 0.001). However, no association between a specific arch zone of a distal anastomosis and the occurrence of spinal cord injury was observed. Rates of SAIs are highest in patients who were treated with a distal anastomosis in zone 2 and a short stent graft (100 mm) with the distal end of the hybrid prosthesis at vertebral level TH 2-3.

Five-year outcomes of endovascular repair of complicated acute type B aortic dissections

ObjectiveThoracic endovascular aortic repair is the standard of care for acute complicated type B aortic dissections, but long-term single-device outcomes are limited. MethodsFifty patients were treated with the Valiant Captivia thoracic stent graft (Medtronic Inc, Santa Rosa, Calif) for acute complicated type B aortic dissections in this prospective, nonrandomized Dissection Trial. All-cause mortality, secondary procedures, and serious adverse events were assessed, and a core lab evaluated images for aortic remodeling. ResultsCompliance for both clinical and imaging follow-up was 78% (18 out of 23) for the available patients at 5 years. Notable baseline characteristics were 86% of patients (43 out of 50) had malperfusion, 20% (10 out of 50) had ruptures, and 94% (46 out of 49) had DeBakey class IIIB dissections. The 5-year freedom from dissection-related mortality, secondary procedures related to the dissection, and endoleaks was 83%, 86%, and 85%, respectively. After 5 years, 89% of patients (16 out of 18) had a completely thrombosed false lumen in the stented segment of the aorta and the true lumen diameter over the length of stent graft was stable or increased for 94% of patients (16 out of 17) while the false lumen diameter was stable or decreased in 77% (13 out of 17) after 5 years. ConclusionsIn the Dissection Trial, patients experienced positive and sustained measures of aortic remodeling. Survival outcomes, need for secondary procedures, and adverse event rates were consistent with previous thoracic endovascular aortic repair studies. Although limitations exist with the follow-up compliance, the Valiant Captivia thoracic stent graft system was effective in the long-term management of acute complicated type B aortic dissections in this patient population with a challenging condition.

Association Between Extent of Stent-Graft Coverage and Thoracic Aortic Remodeling After Endovascular Repair of Type B Aortic Dissection

Purpose: To examine the association between the extent of stent-graft coverage and thoracic aortic expansion after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. Materials and Methods: A retrospective analysis was conducted of 201 patients (mean age 52.4±11.5 years; 178 men) with acute (135, 67.2%) or chronic (66, 32.8%) type B aortic dissection who underwent TEVAR at 4 medical centers. The mean stent-graft length was 157.1±33.3 mm. The percentage of stented descending aorta (PSDA) represented the extent of stent-graft coverage. After using restricted cubic smoothing spline plots to confirm the roughly linear relationship between PSDA and the risk of thoracic aortic expansion, patients were stratified into 2 groups on the median PSDA: the lower group (≤31.3%) and the higher group (>31.3%). Thoracic aortic expansion was defined as a ≥20% increase in the total thoracic aortic volume on the most recent postoperative computed tomography angiography scan compared with the preoperative measurement. The Kaplan-Meier method was used to estimate the cumulative freedom from thoracic aortic expansion after TEVAR; estimates are given with the 95% confidence interval (CI). A multivariable Cox proportional hazards model was used to analyze any independent association of the PSDA as a continuous or categorical variable with the risk of thoracic aortic expansion; results are presented as the hazard ratio (HR) and 95% CI. Results: No patients developed symptoms of spinal cord ischemia during hospitalization. Over a median 12.4 months of imaging follow-up, 34 (16.9%) patients developed thoracic aortic expansion. The estimate of freedom from thoracic aortic expansion at 12 months for the overall PSDA was 84.0% (95% CI 77.8% to 88.6%); between the groups, the freedom from thoracic aortic expansion estimate for the PSDA ≤31.3% group was significantly lower than in the higher group (p=0.032). Regression analysis showed no significant association between the risk of thoracic aortic expansion and the PSDA as a continuous variable (HR 0.97, 95% CI 0.91 to 1.03, p=0.288); however, analyzing the PSDA as a categorical variable indicated a significantly lower risk of thoracic aortic expansion for the PSDA >31.3% group (HR 0.46, 95% CI 0.22 to 0.95, p=0.036) after adjusting for a variety of demographic and anatomical characteristics. Conclusion: More extensive stent-graft coverage appears to improve thoracic aortic remodeling after TEVAR. However, the clinician should balance the benefit of extensive stent-graft coverage and its related risk of spinal cord ischemia.

Outcome After Endovascular Repair of Ruptured Thoracic Aortic Aneurysm: A National Multicenter Study

Introduction - Ruptured descending thoracic aortic aneurysm (rDTAA) is an acute condition with high mortality requiring urgent treatment. The purpose of this multicenter study was to analyze the outcome of thoracic endovascular aortic repair (TEVAR) in patients with rDTAA. Methods - This is a nationwide retrospective study including all patients who underwent TEVAR for rDTAA at six major vascular university centers in Sweden between January 2000 and December 2015. Data from local hospital records and the Swedish vascular registry at the participating centres were reviewed. Outcome measures were analysed using Kaplan-Meier estimator and multivariable Cox-regression. Results - There were 140 patients (mean age 74.1±SD 8.8 [range: 34-91] years; 56% men), with rDTAA. The mean descending aortic aneurysm size was 64.8±19 mm. Hemothorax was present in 64% (89/139) of patients at admission. The median stent graft length was 218 mm (range: 30-800 mm) and the median number of stentgrafts used was 2.0 (range: 1-6). In 53 patients (37.9%), the left subclavian artery was covered to extend the proximal landing zone. Twenty-five patients (17.9%) required proximal revascularization; chimney left carotid artery (n=14), chimney left subclavian artery (n=7), carotid-carotid-subclavian bypass (n=2), and left carotid-subclavian bypass (n=2). The celiac trunc was covered in 15 cases (10.7%) to achieve adequate distal landing zone. A chimney was placed in the SMA in six cases (4.3%) and in the celiac trunc in one case (0.7%). In two patients a multi branched stent graft was used. In total, 61/136 patients (45%) had a major complication within 30-day post TEVAR. Stroke (n=20; 14.7 %) was the most common complication followed by paraplegia (n=13; 9.6%) and major bleeding (n=13; 9.6 %). There were no association between stent graft length or subclavian coverage and paraplegia (OR 1.00, 95% CI 0.998-1.01; P=0.32, and OR 0.56, 95% CI 0.14-2.31; P=0.42; respectively) or subclavian coverage and stroke (OR 1.40, 95% CI 0.46-4.31; P=0.56). Reinterventions were required in 27/137 patients (19.7%). Postoperative bleeding was the only major complication associated with reintervention (OR 3.39, 95% CI 1.05-11.0; P=0.042). Median follow-up time was 18.5 months (range: 0-132 months). The Kaplan-Meier estimated survival was 79.1% at 1 month, 70.8% at 3 months, 64.5% at 1 year, 45.0% at 3 years, and 30.9% at 5 years. Age (HR 1.04; 95 % CI 1.00-1.07; P=0.044), previous stroke (HR 2.31; 95 % CI 1.17-4.55; P=0.016), previous aortic surgery (HR 2.17; 95 % CI 1.18-3.99; P=0.012) as well as postoperative major bleeding (HR 4.29; 95 % CI 2.14-8.60; P=0.001), postoperative stroke (HR 2.73; 95 % CI 1.43-5.22; P=0.002), and renal failure (HR 7.82; 95 % CI 2.53-24.19; P=0.001) were all associated with mortality. Conclusion - This nationwide multicenter study of patients with rDTAA undergoing TEVAR showed acceptable short-term survival but the long-term survival is rather poor. The postoperative complication rate is high and reinterventions are required in one fifth of patients. Patient selection and optimization are of utmost importance to improve outcome.

Distal Stent Graft Induced New Entry: Risk Factors in Acute and Chronic Type B Aortic Dissections

Distal stent graft induced new entry (dSINE) is a rare complication associated with acute and chronic dissections after thoracic endovascular aortic repair (TEVAR) and is linked to a high re-intervention rate. The potential predicting risk factors for dSINE and long term outcome of patients after re-intervention were analysed. This single centre, retrospective study included patients undergoing TEVAR. Multivariable analysis was used to test important interventional parameters such as distal oversizing (dOS), taper ratio (TR), angle between distal stent graft and aorta, acute dissection and stent graft length. Re-intervention characteristics were analysed and further long term follow up after re-intervention were evaluated. One hundred and eighty-five patients were analysed with acute (n=77) and chronic (n=108) dissections after TEVAR with an average follow up of 68.9±32.5 months. During follow up, 12 (6.5%) patients developed dSINE after a median of 22.2±20.7 months. Acute dissection was identified as a major predicting factor for dSINE development (15.8 fold increased odds), followed by increased dOS and TR. The re-intervention rate was higher in the dSINE group (83% vs. 20%, p=.001), but results indicated that no further re-intervention was needed and no new endoleak development occurred up to a mean follow up of 60.7±54.8 months. No dSINE was seen in association with tapered stent grafts. Acute aortic dissection was found to be the major predicting factor for dSINE development, followed by increased dOS and TR. The use of tapered stent grafts might be beneficial for patients with high expected dOS and TR. In the rare case of dSINE occurrence, even when re-intervention is required, the long term prognosis is good.

P5603Distal stent graft induced new entry: risk factors in acute and chronic type B aortic dissections

Abstract Background Distal stent graft induced new entry (dSINE) is a rare complication occurring in acute and chronic dissections after thoracic endovascular aortic repair (TEVAR) and is linked to a high reintervention rate. We analyzed potential predicting risk factors for dSINE and analyzed the long-term outcome in patients after reintervention. Methods In this single-center, retrospective study we evaluated patients after TEVAR and investigated possible predictors for dSINE development. Therefore, we used a multivariate analysis to test important interventional parameters such as distal oversizing (dOS), taper ratio (TR), angle between distal stent graft and aorta, acute dissection and stent graft length. Reinterventional characteristics were analyzed and further long-term follow-ups after reintervention evaluated. Results We analyzed 185 patients with acute (n=77) and chronic (n=108) dissections after TEVAR with a follow-up of 68.9±32.5 months. Within the follow-up period, 12 (6.5%) patients developed dSINE after a median time of 22.2±20.7 months. We identified acute dissection as a major predicting factor for dSINE development with a 15.8 times higher odds, followed by an increased dOS and TR. The reintervention rate was higher in the dSINE group (83% vs. 20%, p=0.001), but reinterventional results were mostly satisfying, including further freedom from reintervention and/or new endoleak development up to a mean follow-up of 60.7±54.8 months. No dSINE was seen in association to tapered stent grafts. Conclusion We found acute aortic dissection as a major predicting factor for dSINE development, followed by increased dOS and TR. The use of tapered stent grafts might be beneficial in cases with expected high dOS and TR. In rare cases with dSINE occurrence, reintervention is often required, but has a good prognosis even after years.

Stent-Graft Length Is Associated with Decreased Patency in Treatment of Central Venous Stenosis in Hemodialysis Patients

Central venous occlusion may occur in hemodialysis patients, resulting in arm or facial swelling and failure of dialysis access. Endovascular management with balloon angioplasty or stenting has been described, but there are minimal data on the use of covered stents in this pathology. We sought to review a single institution's experience with the use of covered stents for central venous occlusive disease in hemodialysis patients. A retrospective review of all patients undergoing placement of covered stents between April 2014 and December 2016 for central venous occlusive disease to preserve a failing dialysis access was performed. Patients' records were reviewed to identify demographics, medical comorbidities, operative variables, primary patency rates, and secondary interventions. A total of 29 patients were included in the analysis. Viabahn (W.L. Gore and Associates, Flagstaff, AZ) stent grafts were exclusively used in all patients. Technical success rate was 100%. The patients were predominantly female (65.5%), with a mean age of 67.9±12.1 and medical comorbidities of hypertension (86%), diabetes (76%), and tobacco use (7%). The majority (86%) had prior angioplasty and 17 of 29 (59%) patients had previous central venous catheters. The right brachiocephalic vein was the most commonly stented vessel (28%). The median stent length and diameter used were 50millimeters (range 25-100millimeters) and 13millimeters (range: 9-13millimeters), respectively. The majority of patients (83%) received a single stent, with only 2 patients requiring more than one. Median follow-up was 24months (range: 6-41months). Four of 29 (13.8%) patients developed symptomatic stent restenosis requiring secondary intervention, all of which occurred in patients with primary stenosis between 50% and 75%. When compared to the patients without restenosis, longer stents were found to be significantly associated with restenosis (62.5centimeters, interquartile range [IQR]: 0] vs. 50centimeter, IQR: 0, P=0.002). Primary patency rates were 92.9%, 91.7%, and 80.0% at 6, 12, and 24months respectively. Secondary patency rates were 96.4%, 95.8%, and 93.3% at 6months, 12months, and 24months, respectively. The overall primary patency rate was estimated at 86.2% using Kaplan-Meier analysis at 30.5months (95% confidence interval: 26.5-34.5months). Covered stent grafts have reasonable primary patency and excellent secondary patency when used for central venous stenosis in dialysis patients. Stent-graft length is associated with poorer long-term patency rates.

Distal Stent Graft-Induced New Entry After TEVAR of Type B Aortic Dissection: Experience in 15 Years

Experience is limited with distal stent graft-induced new entry (SINE) after thoracic endovascular aortic repair (TEVAR) of type B dissection (TBAD). We report the management strategy and outcomes in such patients. Clinical data were analyzed for 95 patients (age, 53.2 ± 10.9 years; 82 men) who presented with distal SINE after TEVAR for TBAD. Follow-up was 100% for 7.2 ± 3 years after primary TEVAR. Distal SINE occurred at a mean of 2.7±2.4 years. Re-TEVAR was performed for 78, with routine stent grafts in 64 and a more tapered graft in 14. Three patients were managed surgically and 14 medically. Two patients died after re-TEVAR. During follow-up at 5.8 ± 2.9 years, late death occurred in 19 patients, 7 with medical therapy and 12 with re-TEVAR. Distal SINErecurred in 11 at 3.5 ± 1.7 years after re-TEVAR. Reintervention significantly improved survival up to 8years compared with medical therapy (88.3% vs 63.5%, p= 0.001). In 64 patients with routine stent grafts, mortality was 24%, distal SINE recurred in 20%, and recurrence-free survival was 56% at 6 years. Neither death nor recurrence of SINE occurred in 14 patients with a more tapered stent graft. Predictors for distal SINE after primary TEVAR were stent graft length (hazard ratio, 0.984; p= 0.037) and chronic phase (hazard ratio, 1.725; p= 0.049). In TBAD patients with distal SINE after TEVAR, reintervention with re-TEVAR could improve long-term survival significantly. Recurrence of distal SINE was high after re-TEVAR using routine stent grafts. More tapered stent grafts may be helpful in preventing the recurrence of distal SINE.

Measuring the greater curvature length of virtual stent graft can provide accurate prediction of stent graft position for thoracic endovascular aortic repair

ObjectiveThe objective of this study was to assess the accuracy of predicting stent graft position for thoracic endovascular aortic repair by measuring three lengths of the virtual stent graft: smaller curvature (SC), center lumen line (CL), and greater curvature (GC). MethodsFrom January 2012 to December 2016, patients treated at our institution were analyzed retrospectively. Patients who were treated with more than two devices, patients treated for aortic dissection, and cases without complete preoperative or postoperative computed tomography (CT) data were excluded. From the preoperative CT data, the virtual stent graft image based on the SC (SCVS) was created so that its SC length matched that of the stent graft actually used. In the same manner, virtual stent graft images based on the CL (CLVS) and GC (GCVS) were created. These virtual stent graft images were created using SYNAPSE VINCENT software (Fujifilm Co, Tokyo, Japan) and superimposed on the postoperative CT image to measure the misalignment between these virtual stent graft images and the actual stent graft. These misalignments were compared using Wilcoxon signed rank sum test. In addition, the actual length (AL) of the stent graft was measured on the basis of the CL from postoperative CT data and compared with its original length (OL). ResultsA total of 35 cases were analyzed. Twenty-six patients were men. The average age of the patients was 72.4 ± 13.0 years. The proximal landing zone were located at the descending aorta (n = 11) and the aortic arch (n = 24). The misalignment between SCVS, CLVS, and GCVS and actual stent graft position was −47.8 ± 18.1 mm, −21.5 ± 9.4 mm, and 5.3 ± 7.4 mm, respectively. The difference in means between the three groups was significant (P < .001). The relationship between the AL based on CL and OL was represented by the formula AL = OL * 0.92 − 0.05 (in the descending aorta) and AL = OL * 0.77 + 9.85 (in the aortic arch). ConclusionsCompared with CLVS and SCVS, GCVS was the most accurate predictor of stent graft position for thoracic endovascular aortic repair.

Anatomic Suitability for Standard, “Off-the-Shelf” Thoracic Single Side-Branched Endograft in Patients With Type B Aortic Dissection

Treatment of type B aortic dissections with thoracic endovascular aortic repair (TEVAR) has been adopted in many centers with the goal of covering the proximal entry tear. Coverage of the left subclavian artery is commonly required to achieve a dissection-free proximal seal zone. A novel thoracic single side-branched (TSSB) endograft offers a potential off-the-shelf option to achieve total endovascular incorporation of the left subclavian artery during zone 2 TEVAR. The aim of this study was to determine what percentage of patients with type B aortic dissection who require zone 2 TEVAR meet the anatomic requirements for this device. All consecutive patients undergoing TEVAR for type B aortic dissections at a single institution from 2006 to 2016 were evaluated. Three-dimensional centerline reconstruction of preoperative computed tomography angiography was performed to identify the diameter of the aorta, distances between branch vessels, diameter of the target branch vessel, and location of the primary entry tear. Only patients who required zone 2 TEVAR were included in the analysis. The primary outcome was percentage of patients who met all anatomic requirements for the TSSB endograft. The specific requirements leading to nonsuitability were also calculated. Eighty-seven patients who underwent TEVAR for type B aortic dissection were reviewed; 57 of 87 would have required zone 2 TEVAR. Indications for TEVAR were malperfusion (12), aneurysm (15), persistent pain (22), rupture (3), uncontrolled hypertension (5), and other (3). Mean follow-up was 19 months (range, 1-72 months). Only 17 patients (30%) met all the requirements for anatomic suitability (Fig). The reasons for failing anatomic suitability were covered stent graft length proximal to the branch portal (61%), aortic diameter at the proximal seal zone (11%), left subclavian diameter (16%), left subclavian length to its first branch (14%), and access vessel diameter (40%). Although the standard TSSB endograft can allow a more proximal seal zone and eliminate the need for open aortic arch debranching, only 30% of patients with type B dissection who require zone 2 TEVAR meet all the anatomic requirements for this device. The most common reason for failure of anatomic suitability is the proximity of the left carotid to the left subclavian origin.