Stent Graft Diameter Research Articles

Proximal Aortic Landing Zone Dilation Following Thoracic Endovascular Aortic Repair for Type B Aortic Dissection: Incidence and Clinical Implications.

This study aimed to assess the incidence, predictors, and clinical relevance of proximal aortic landing zone dilation (PALD) following thoracic endovascular aortic repair (TEVAR) for acute and chronic type B aortic dissection (TBAD). A retrospective analysis of 47 patients who underwent TEVAR for TBAD at a single center was conducted. PALD was defined as a ≥5 mm increase in aortic diameter at two of three measurement sites (at 0, 1 and 2 cm distal to the stent graft proximal edge) at postoperative computed tomography angiography (CTA). The primary endpoint was the development of PALD. Secondary endpoints included entry fIow type IA, device migration and reintervention rates. Kaplan-Meier analyses was employed to evaluate PALD-free survival. PALD occurred in 19% of patients (n=9) during a median follow-up of 62 months. A stent graft diameter >36 mm significantly predicted PALD (p=.022), with an area under the curve of 0.75 (sensitivity: 89%, specificity: 58%). No significant associations were found between PALD and reinterventions or type Ia entry flow. Kaplan-Meier analysis revealed a median PALD-free survival of 156 months (95% CI: 92-210). Patients with PALD demonstrated a greater increase in aortic diameter at maximum follow-up compared to non-PALD patients (p<.001). Other demographic, anatomic, and procedural factors were not associated with PALD, and especially oversizing did not correlate with PALD development. PALD occurred in a significant proportion of patients following TEVAR for TBAD, with stent graft diameter serving as key predictor. PALD did not correlate with adverse clinical outcomes in this cohort.

Long-term results of the frozen elephant trunk technique in primary chronic type B aortic dissection.

The aim of this study is to analyze long-term results of the total aortic arch replacement with the frozen elephant trunk technique for primary chronic type B aortic dissection. Among 322 patients who had the frozen elephant trunk technique, 43 (13.4%) patients (median age, 64.0years) with primary chronic type B aortic dissection were analyzed. The patients underwent surgery at a median of 27.0months after the onset of aortic dissection. The false lumen was patent in 30 (69.8%) patients preoperatively. Two patients suffered paraplegia and another died of cerebral infarction. Complete thrombosis of the peri-stent false lumen was achieved in 36 (83.7%) patients. Overall survival, freedom from aortic events, and freedom from aortic reintervention were 83.5%, 37.2%, and 42.2% at 5years, respectively. Survival rates of the patients with or without aortic events were 75.0% and 95.8% at 5years (Log-rank, p = 0.22). Late aortic events occurred in 19 (44.2%) patients including distal stent graft-induced new entry, type Ib endoleak, and false lumen dilation. The ratio of the stent graft diameter to the preoperative short axis diameter of the true lumen (hazard ratio, 1.90; 95% confidence interval, 1.01-3.59), and the maximal diameter of a postdissection aneurysm (1.07; 1.01-1.12) were the significant multivariate risk predictors of late aortic events. Late aortic events occurr fairly frequently, and new strategies need to be explored to enhance the effectiveness of this procedure in the future.

Off-the-Shelf Single-Fenestrated Endograft for Emergent Juxtarenal and Pararenal Abdominal Aortic Aneurysm.

Endovascular solutions to emergent juxtarenal and pararenal abdominal aortic aneurysms (AAAs) are complicated. Endovascular aortic repair (EVAR) with in situ laser fenestration (ISLF) is promising but requires a period of visceral ischemia. With an off-the-shelf, single superior mesenteric artery (SMA)-fenestrated device mesenteric ischemia is avoided and renal ischemia decreased. The aim was to develop an optimized design of such an endograft suitable for >90% of juxtarenal and pararenal AAAs. Single-center analysis on 44 consecutive preoperative CTs for previously elective fenestrated EVARs for juxtarenal and pararenal aneurysms. Anatomical characteristics were analyzed to define: (1) shortest aortic coverage above SMA fenestration to achieve ≥4 cm seal; (2) feasibility of a scallop for the celiac artery; (3) shortest distance between the SMA and lowest renal, to facilitate renal ISLF in a straight endograft; (4) distance from the lowest renal to the aortic bifurcation, to allow an overlapping zone >40 mm with a bifurcated stent graft; (5) aortic diameter in the sealing zone, for optimal proximal stent graft diameter with 10% to 30% oversizing; (6) the final design was then tested on individual level. (1) The stent graft needs to start 40 mm above the SMA fenestration to achieve a 4 cm sealing zone in >90% of cases. (2) A proximal sealing zone of 40 mm without a scallop covers 77% of celiac arteries. With an addition of a 20 mm deep, 20 mm wide scallop at 12:30, the stent graft still covers 27% of celiacs. This suggests that a scallop would not be practically feasible. (3) In >90% of cases, the lowest renal was <31 mm from the SMA, suggesting that the tapering should start 30 mm below the SMA. (4) The distance from the lowest renal to the aortic bifurcation ranged from 82 to 166 mm. This allows for a 20 mm tapering and 50 mm straight part in all cases. (5) The 5th and 95th percentile of the aortic diameter in the sealing zone was 22 and 31 mm, respectively. Thus, 2 different stent graft diameters (28 and 34 mm) would fit >90% of cases. (6) The final design was suitable in 91% cases. Two sizes of a single-fenestrated aortic stent graft without scallop cover >90% of juxtarenal and pararenal anatomies. Emergent juxta- and pararenal aortic aneurysms is a difficult clinical scenario that continuously challenges physicians. An endovascular option is in situ laser fenestrated endografts. One risk with these is the complete visceral ischemia occurring before the fenestrations are completed. An off-the-shelf single-fenestrated stent graft facilitates the treatment by removing the ischemia time for the SMA and reducing the ischemia time for the celiac and renal arteries thus decreasing the risk of visceral ischemia complications.

Endovascular Popliteal Artery Aneurysm Repair Using an "Off-Label" Abdominal Endograft Limb-Module with Nitinol-Ring Structure: A Single Centre Experience.

To evaluate endovascular popliteal artery aneurysm repair using a an "off-label" abdominal endograft limb-module with nitinol-ring structure. Retrospective observational study of 14 popliteal artery aneurysms in 12 male patients (mean age 76years and median ASA grade 3) treated electively using the Anaconda™ endograft limb (Terumo Aortic) at a single teaching hospital. Eight limbs were treated percutaneously and 6 limbs required surgical arterial exposure. The mean popliteal artery aneurysm diameter treated was 3.6cm (range 2.1-5.3cm). Stent-graft diameters and lengths used were 10-15 and 60-140mm, respectively. The median covered stented length was 218mm (range 160-270mm) and median duration of follow-up was 3.7years. Outcomes assessed included technically successful aneurysm exclusion, primary patency, re-intervention and survival. All patients had successful stent-graft deployment and aneurysm exclusion, with no early complications or mortality at 30days. Primary stent-graft patency at 1, 3 and 4years was 93%, 75%, and 64%. By 8years, patency had declined with 29% (2/14) stent-grafts patent. 7/14 limbs occluded; 3 underwent re-intervention (2 surgical, 1 endovascular). There were no deaths related to the procedure. Freedom from re-intervention and survival at 1/5years was 93%/84% and 93%/67%, respectively. The Anaconda™ endograft limb for endovascular popliteal artery aneurysm repair offers good mid-term patency and acceptable long-term patency up to 4years when compared with other grafts and open surgery. It may be considered in older comorbid patients unfit for surgery and can be performed percutaneously under local anaesthesia when anatomically feasible.

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.

Abstract 530: Explantation Vs Graft Preserving Strategy Following Primary Endovascular Aneurysm Repair

Background: Continuous sac expansion could result in rupture, requiring aggressive management with re-intervention to abolish the risk of rupture. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary. We aim to scrutinise our 20 years of EVAR practice, strategies indications for management and re-interventions following primary endovascular aneurysm repair (EVAR). Methods: We performed 1555 aortic interventions over study period, including 910 EVARs. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 136 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Results: In total, 4.84% (44/910) patients underwent re-intervention post-primary EVAR; 18 EVAR GORE SalvAge Fabric Technique (ARAFAT), 12 double breastings, and 14 explantations (Figure 1) . Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while re-intervention time was 70.2 ± 6.98 months. Mean sac size before the primary EVAR and re-intervention were 6.00 and 7.51 cm. Polyester (61.40%, 12/18) was the most commonly employed stent-graft material. Factors associated with the need for reintervention and likelihood of chronic fabric fatigue failure (CFFF) included the use of more than three modular stent-graft components (3.42 ± 1.31); with the proximal stent-graft diameter of 31.6 ± 3.80 cm and the use of iliac limbs more than 18 mm. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Conclusions: Increasing complications post-EVAR necessitates developing and studying re-intervention strategies to salvage existing endograft and/or address graft-related complications. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary.

Features and risk factors of early intraluminal thrombus formation within the frozen elephant trunk stent graft

ObjectiveThe frozen elephant trunk is a standard treatment method for aortic arch pathologies extending into the descending aorta. We previously described the phenomenon of early postoperative intraluminal thrombosis within the frozen elephant trunk. We investigated the features and predictors of intraluminal thrombosis. MethodsA total of 281 patients (66% male, mean age 60 ± 12 years) underwent frozen elephant trunk implantation between May 2010 and November 2019. In 268 patients (95%), early postoperative computed tomography angiography was available to assess intraluminal thrombosis. ResultsThe incidence of intraluminal thrombosis after frozen elephant trunk implantation was 8.2%. Intraluminal thrombosis was diagnosed early after the procedure (4.6 ± 2.9 days) and could be successfully treated with anticoagulation in 55% of patients. A total of 27% developed embolic complications. Mortality (27% vs 11%, P = .044) and morbidity were significantly higher in patients with intraluminal thrombosis. Our data showed a significant association of intraluminal thrombosis with prothrombotic medical conditions and anatomic slow flow features. The incidence of heparin-induced thrombopenia was higher in patients with intraluminal thrombosis (18% vs 3.3%, P = .011). Stent-graft diameter index, anticipated endoleak Ib, and degenerative aneurysm were significant independent predictors of intraluminal thrombosis. Therapeutic anticoagulation was a protective factor. Glomerular filtration rate, extracorporeal circulation time, postoperative rethoracotomy, and intraluminal thrombosis (odds ratio, 3.19, P = .047) were independent predictors of perioperative mortality. ConclusionsIntraluminal thrombosis is an underrecognized complication after frozen elephant trunk implantation. In patients with risk factors of intraluminal thrombosis indication for frozen elephant trunk should be carefully evaluated and postoperative anticoagulation considered. Early thoracic endovascular aortic repair extension should be considered in patients with intraluminal thrombosis to prevent embolic complications. Stent-graft designs should be improved to prevent intraluminal thrombosis after frozen elephant trunk implantation.

Stent Graft Placement for the Treatment of Hepatic Artery Injury in Patients with Cancer: Primary Patency and Clinical Outcomes

PurposeTo evaluate the safety, primary patency, and clinical outcomes of hepatic artery stent graft (SG) placement for vascular injuries. Materials and MethodsPatients treated with hepatic arterial SG placement for vascular injuries between September 2018 and September 2021 were reviewed. Data on demographic characteristics, indication, stent graft characteristics, antiplatelet/anticoagulant use, clinical success rate, complications, and type of follow-up imaging were collected. Follow-up images were reviewed by 2 independent reviewers to assess primary patency. A time-to-event analysis was performed. The median duration of stent graft patency was estimated using Kaplan-Meier curves. A Cox proportional hazard model was used to evaluate factors related to stent graft patency. ResultsThirty-five patients were treated with hepatic arterial SG placement, 11 for postoperative bleeds and 24 for hepatic artery infusion pump catheter–related complications. Clinical success was achieved in 32 (91%) patients (95% CI, 77–98). The median primary patency was 87 days (95% CI, 73–293). Stent grafts of ≥6-mm diameter retained patency for a longer duration than that with stent grafts of smaller diameters (6 mm vs 5 mm; hazard ratio, 0.35; 95% CI, 0.14–0.88; P = .026; and 7+ mm vs 5 mm; hazard ratio, 0.27; 95% CI, 0.09–0.83; P = .023). Anticoagulation/antiplatelet regimen was not associated with increased stent graft patency duration (P > .05). Only minor complications were reported in 2 (5.7%) patients. ConclusionsStent grafts can be used safely and effectively to treat injuries of the hepatic artery. Stent graft diameters of ≥6 mm seem to provide more durable patency.

Two decades of experience in explantation and graft preserving strategies following primary endovascular aneurysm repair and lessons learned.

We aim to scrutinize our evolving re-intervention strategies following primary endovascular aortic aneurysm repair (EVAR) - EVAR GORE SalvAge Fabric Technique (ARAFAT), aortic sac double breasting with endograft preservation, and stent-graft explantation. We performed 1,555 aortic interventions over the study period, including 910 EVARs. Factors associated with the need for reintervention and the likelihood of chronic fabric fatigue failure (CFFF) were investigated. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 136 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Forty-four (4.84%) patients underwent re-intervention post-primary EVAR; 18 ARAFATs, 12 double breastings, and 14 explantations. Choice of re-intervention was based on patient fitness and mode of failure. Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while mean time to re-intervention was 70.20 ± 6.98 months. The mean sac size before the primary EVAR and re-intervention was 6.00 ± 1.75 cm and 7.51 ± 1.94 cm, respectively. Polyester (61.40%) was the most commonly employed stent-graft material. Use of more than three modular stent-graft components (3.42 ± 1.31, p = 0.846); with the proximal stent-graft diameter of 31.6 ± 3.80 cm (p = 0.651) and the use of iliac limbs more than 17 mm (p = 0.364), all added together are contributing factors. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Our re-intervention strategies matured from stent graft explantation to graft preservation with endovascular relining of the stent-graft. Graft preservation with aortic sacotomy and double breasting were used to manage concealed ELs due to aortic hygroma.

O077 Explantation vs graft preserving strategy following primary endovascular aneurysm repair: two decades of EVAR and lessons learned

Abstract Introduction Continuous sac expansion could result in rupture, requiring aggressive management with reintervention to abolish the risk of rupture. Re-intervention could be achieved through salvage of the primary endograft through graft preserving strategy or explantation as necessary. We aimed to scrutinise our 20 years of EVAR practice, strategies indications for management and reinterventions following primary endovascular aneurysm repair (EVAR). Methods We performed 1480 aortic interventions over the study period, including 910 EVARs. Using conventional and innovative diagnostic modalities with Prone contrASt enHanced computed tomography Angiography (PASHA), 133 endoleaks (ELs) were identified (15 type I, 98 type II; 18 type III; 5 type IV). Results In total, 44 patients underwent re-intervention post-primary EVAR;18 EVAR GORE SalvAge Fabric Technique (ARAFAT), 12 double breastings, and 14 explantations. Mean EL detection duration following primary EVAR was 53.3 ± 6.82 months, while re-intervention time was 70.2 ± 6.98 months. Mean sac size before the primary EVAR and re-intervention were 6.00 and 7.51 cm. Polyester (61.40%) was the most commonly employed stent-graft material. Factors associated with the need for reintervention and the likelihood of chronic fabric fatigue failure (CFFF) included the use of more than three modular stent-graft components (3.42 ± 1.31); with the proximal stent-graft diameter of 31.6 ± 3.80 cm and the use of iliac limbs more than 18 mm. We had one peri-operative mortality following explantation due to sepsis-induced multiorgan failure. Conclusion Increasing complications post-EVAR necessitates developing and studying reintervention strategies to salvage existing endograft and/or address graft-related complications. Take-home message Increasing complications post-EVAR necessitates developing and studying re-intervention strategies to salvage existing endograft and/or address graft-related complications.

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.

Aortic Healing Appears to Occur Rapidly after Successful Endovascular Sealing of Blunt Thoracic Aortic Injury

The traumatic nature of blunt thoracic aortic injury (BTAI) would suggest that healing of the aorta would occur once the injured area is shielded from aortic pressure. This would be in contrast to degenerative aortic diseases which often continue to degenerate despite coverage. We hypothesize that after successful thoracic aortic endografting (TEVAR) that the aorta rapidly heals itself leaving minimal to no trace of the residual injury. BTAI that were successfully covered with TEVAR from 2006 to 2019 were collected. Those with failed sealing or a lack of follow-up scans were excluded. Centerline aortic diameters were measured at healthy aorta 1cm above (D1) and below the injury (D3) and at the widest point of injury (D2) on preoperative and initial postoperative computed tomography (CT) scans. Postoperative CTs were examined for residual signs of aortic injury including residual periaortic hematoma, persistent thrombosed pseudoaneurysm, or thickened aortic wall. Diameter changes in the healthy and injured aortic segments were compared pre and post TEVAR. Aortic diameter changes were analyzed with the Student's t-test. Twenty four patients were identified with sealed BTAI. The mean graft diameter was 24.2±3.2mm with oversizing of 10.74±6.1 % at D1 and 19.52±10.22 % at D3. Postoperative CTs occurred at 61.25±123.6days with one outlier at 602days. Injured aortic segments (D2) had significantly larger diameters compared to D1 (28.94±5.08mm vs. 22.14±3.08mm, P<0.001). After TEVAR, 23/24 (95.8%) had no residual radiographic evidence of aortic injury by 2months. One patient had a persistent thrombosed pseudoaneurysm likely due to more than 50% disruption of the aortic wall. Post TEVAR, there was a significant diameter reduction at D2 by 13.8% (29.10±5.27mm vs. 24.8±4.2mm, P<0.001) which was within 2.45% of the mean stent graft diameter. The healthy aorta dilated to accommodate the graft by 9% at D1 (21.9±3.0 vs. 23.7±2.5mm, P<0.001) and 17% at D3 (20.6±3.4mm vs. 23.6±3.2mm, P<0.001). TEVAR promotes rapid aortic healing in BTAI with no evidence of residual aortic injury suggesting that a long-term seal is not necessary. The healthy aorta dilates to the stent graft size, as expected, whereas the injured aortic segment heals around the stent graft and assumes its diameter as well. Massive disruption of the aortic wall may preclude early healing.

Institutional practice in sizing of the hybrid prosthesis in frozen elephant trunk surgery.

The frozen elephant trunk (FET) technique for total arch replacement (TAR) is widely used for repair of aortic arch dissections and aneurysms. Despite its widespread adoption, there are no international or regional guidelines for the sizing of FET prostheses in TAR. We seek to highlight the heterogeneity thereof and pave the way for evidence-based guidelines to advise FET prosthesis sizing in TAR. An online questionnaire was sent to 22 specialist aortic surgeons from 13 different countries across North America, Europe, Asia, and Australia, inquiring about each surgeon's approach to FET prosthesis sizing. The results were then pooled for frequency analysis. All 22 surgeons responded to the questionnaire. Zone 2 is preferred implantation zone for AAD, CAD, and TAA (selected by 72.7%, 72.7%, and 68.2% respectively). The maximal diameter of the true lumen in the DTA is the most common index measurement for AAD and CAD (40.9% and 59.1%, respectively). Stent-graft diameters equal to the index measurement is the most common approach for AAD and CAD (77.3% and 45.5%, respectively) while 59.1% of surgeons oversize the index diameter by 10% for TAA; 100 mm is the preferred length for 50.0%, 27.3%, and 40.9% of surgeons in AAD, CAD, and TAA respectively. There is considerable heterogeneity in sizing practices for FET prostheses internationally, with variable evidence for its impact on clinical outcomes. This issue would be aided by the development of evidence-based guidelines to inform clinical decision making.

A new dissection-specific hybrid stent graft for patients with DeBakey type I aortic dissection.

We present our first experience of using a new dissection-specific hybrid stent graft (SG) (the 'Soft Elephant Trunk') in the frozen elephant trunk technique, in patients with non-acute DeBakey type I aortic dissection. Between September 2016 and February 2021, patients with non-acute DeBakey type I aortic dissection underwent the frozen elephant trunk procedure at our centre using 3 SG types: group Z used stiff, distal Z-shaped nitinol SGs (E-Vita, Medtronic); group R used a stiff, ring-shaped nitinol SG (Thoraflex); and group S used a soft, distal dissection-specific SG. Predictors of distal SG-induced new entry were analysed. End points were hospital- and midterm-follow-up results. The study comprised 109 patients with 46 (42.2%), 22 (20.2%) and 41 (37.6%) patients in groups Z, R and S, respectively. No significant differences were found in early outcomes. Freedom from distal SG-induced new entry was comparable in groups Z, R and S (68.9% vs 92.9% vs 100%, log-rank = 0.14). There was no significant difference in follow-up between the groups. Four-year survival rates were 80.44%, 71.59% and 95.06% in groups Z, R and S, respectively. On multivariable analysis, the presence of connective tissue disorders [hazard ratio (HR) = 5.62, P = 0.11] and SG diameter (HR = 1.37, P = 0.034) were strong predictors of distal SG-induced new entry. Dissection-specific hybrid SG with a soft distal end is effective in patients with non-acute DeBakey type I aortic dissection. Compared to non-soft distal SGs, this can reduce the incidence of distal complications. Long-term outcomes are necessary to determine the potential advantages and disadvantages of the new prosthesis.

Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value = 7.9, p < .001) and oversizing (t value = 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% – 4.8%) and 14.4% (95% CI 11.0% – 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 – 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 – 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 – 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 – 6.9). AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

Results After Open and Endovascular Repair of Popliteal Aneurysm: A Matched Comparison Within a Population Based Cohort

To identify factors affecting the outcome after open surgical (OSR) and endovascular (ER) repair of popliteal artery aneurysm (PA) in comparable cohorts. A matched comparison in a national, population based cohort of 592 legs treated for PA (2008 – 2012), with long term follow up. Registry data from 899 PA patients treated in 2014 – 2018 were analysed for time trends. The 77 legs treated by ER were matched, by indication, with 154 legs treated with OSR. Medical records and imaging were collected. Analysed risk factors were anatomy, comorbidities, and medication. Elongation and angulations were examined in a core lab. The main outcome was occlusion. Patients in the ER group were older (73 vs. 68 years, p = .001), had more lung disease (p = .012), and were treated with dual antiplatelet therapy or anticoagulants more often (p < .001). The hazard ratio (HR with 95% confidence intervals) for occlusion was 2.69 (1.60 – 4.55, p < .001) for ER, but 3.03 (1.26 – 7.27, p = .013) for poor outflow. For permanent occlusion, the HR after ER was 2.47 (1.35 – 4.50, p = .003), but 4.68 (1.89 – 11.62, p < .001) for poor outflow. In the ER subgroup, occlusion was more common after acute ischaemia (HR 2.94 [1.45 – 5.97], p = .003; and poor outflow HR 14.39 [3.46 – 59.92], p < .001). Larger stent graft diameter reduced the risk (HR 0.71 [0.54 – 0.93], p = .014). In Cox regression analysis adjusted for indication and stent graft diameter, elongation increased the risk (HR 1.020 per degree [1.002 – 1.033], p = .030). PAs treated for acute ischaemia had a median stent graft diameter of 6.5 mm, with those for elective procedures being 8 mm (p < .001). Indications and outcomes were similar during both time periods (2008 – 2012 and 2014 – 2018). In comparable groups, ER had a 2.7 fold increased risk of any occlusion, and 2.4 fold increased risk of permanent occlusion, despite more aggressive medical therapy. Risk factors associated with occlusion in ER were poor outflow, smaller stent graft diameter, acute ischaemia, and angulation/elongation. An association between indication, acute ischaemia, and small stent graft diameter was identified.

Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value= 7.9, p < .001) and oversizing (t value= 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% - 4.8%) and 14.4% (95% CI 11.0% - 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 - 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 - 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 - 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 - 6.9). AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

Sizing of the hybrid stent-graft for the frozen elephant trunk procedure

Objective . The aim of study was to determine the tactics of choosing the optimal diameter of stent-graft in open hybrid repair of thoracic aorta based on the analysis of literature and the experience of Petrovsky National Research Centre of Surgery. Material and Methods. A hybrid approach using the frozen elephant trunk (FET) technique is currently the safest and most optimal approach for thoracic aorta repair in case of extended pathology of all thoracic aorta segments, including the arch and descending thoracic aorta. Despite this technique has been used for over 15 years, there is no agreement in the current literature regarding the algorithm for choosing the optimal stent-graft diameter. A total of 135 FET procedures were performed at our centre from 2013 to 2020. The average age of patients was 52.8 ± 11.5 years. We analyzed our own experience and current literature to determine the optimal tactics for sizing the hybrid stent-graft for FET procedure. Results. One of the main factors influencing the tactics of selecting the stent-graft diameter is the nature of pathology. The experience of most surgeons suggests that the size of stent-graft should not excessively exceed the diameter of a true canal in chronic dissection and the overall diameter in case of acute aortic dissection. In case of aneurysms, most authors use stent-grafts with the diameters exceeding distal landing zone diameter by 10–20%. Some authors consider it necessary to preoperatively measure the calculated diameter based on multislice computed tomography (CT) data, whereas many other authors prefer intraoperative measurements. Conclusion. The use of a stent-graft, which is too large, can result in a high risk of new fenestration at the distal end level during the postoperative period and follow-up complications, whereas stent-graft, which is too small, would not allow the adequate fit in the distal part. Therefore, the choice of optimal stent-graft size remains one of the key issues in hybrid thoracic aortic surgery.

Results After Open and Endovascular Repair of Popliteal Aneurysm: A Matched Comparison Within a Population Based Cohort

To identify factors affecting the outcome after open surgical (OSR) and endovascular (ER) repair of popliteal artery aneurysm (PA) in comparable cohorts. A matched comparison in a national, population based cohort of 592 legs treated for PA (2008 - 2012), with long term follow up. Registry data from 899 PA patients treated in 2014 - 2018 were analysed for time trends. The 77 legs treated by ER were matched, by indication, with 154 legs treated with OSR. Medical records and imaging were collected. Analysed risk factors were anatomy, comorbidities, and medication. Elongation and angulations were examined in a core lab. The main outcome was occlusion. Patients in the ER group were older (73 vs. 68 years, p= .001), had more lung disease (p= .012), and were treated with dual antiplatelet therapy or anticoagulants more often (p < .001). The hazard ratio (HR with 95% confidence intervals) for occlusion was 2.69 (1.60 - 4.55, p < .001) for ER, but 3.03 (1.26 - 7.27, p= .013) for poor outflow. For permanent occlusion, the HR after ER was 2.47 (1.35 - 4.50, p= .003), but 4.68 (1.89 - 11.62, p < .001) for poor outflow. In the ER subgroup, occlusion was more common after acute ischaemia (HR 2.94 [1.45 - 5.97], p= .003; and poor outflow HR 14.39 [3.46 - 59.92], p < .001). Larger stent graft diameter reduced the risk (HR 0.71 [0.54 - 0.93], p= .014). In Cox regression analysis adjusted for indication and stent graft diameter, elongation increased the risk (HR 1.020 per degree [1.002 - 1.033], p= .030). PAs treated for acute ischaemia had a median stent graft diameter of 6.5 mm, with those for elective procedures being 8 mm (p < .001). Indications and outcomes were similar during both time periods (2008 - 2012 and 2014 - 2018). In comparable groups, ER had a 2.7 fold increased risk of any occlusion, and 2.4 fold increased risk of permanent occlusion, despite more aggressive medical therapy. Risk factors associated with occlusion in ER were poor outflow, smaller stent graft diameter, acute ischaemia, and angulation/elongation. An association between indication, acute ischaemia, and small stent graft diameter was identified.