Postdissection aortic aneurysm sac enlargement after fenestrated and branched endovascular aortic aneurysm repair.

OBJECTIVES: Aneurysm sac changes after fenestrated-branched endovascular aneurysm repair (FBEVAR) for postdissection thoracoabdominal aortic aneurysms (PD-TAAs) are poorly understood. Partial thrombosis of the false lumen and endoleaks may impair sac regression. To characterize sac changes after FBEVAR for PD-TAAs, this study examined midterm results and predictors for sac enlargement. METHODS: FBEVARs performed for PD-TAAs in 10 physician-sponsored investigational device exemption studies from 2008 to 2023 were analyzed. The maximum aortic aneurysm diameter was compared between the 30-day computed tomography angiogram and follow-up imaging studies. Aneurysm sac enlargement was defined as an increase in diameter of ≥5 mm. Kaplan-Meier curves and Cox regression were used to evaluate sac enlargement and midterm FBEVAR outcomes. RESULTS: Among 3296 FBEVARs, 290 patients (72.4% male; median age, 68.4 years) were treated for PD-TAAs. Most aneurysms treated were extent II (72%) and III (12%). Mean aneurysm diameter was 66.5 ± 11.2 mm. Mortality at 30 days was 1.4%. At a mean follow-up of 2.9 ± 1.9 years, at least one follow-up imaging study revealed sac enlargement in 43 patients (15%), sac regression in 115 patients (40%), and neither enlargement nor regression in 137 (47%); 5 (2%) demonstrated both expansion and regression during follow-up. Freedom from aneurysm sac enlargement was 93%, 82%, and 80% at 1, 3, and 5 years, respectively. Overall, endoleaks were detected in 27 patients (63%) with sac enlargement and 143 patients (58%) without enlargement (P = .54). Sac enlargement was significantly more frequent among older patients (mean age at the index procedure, 70.2 ± 8.9 years vs 66.5 ± 11 years; P = .04) and those with type II endoleaks at 1 year (74% vs 52%; P = .031). Cox regression revealed age >70 years at baseline (hazard ratio [HR], 2.146; 95% confidence interval [CI], 1.167-3.944; P = .010) and presence of type II endoleak at 1 year (HR, 2.25; 95% CI, 1.07-4.79; P = .032) were independent predictors of sac enlargement. Patient survival was 92%, 81%, and 68% at 1, 3, and 5 years, respectively. Cumulative target vessel instability was 7%, and aneurysm-related mortality was 2% at 5 years. At least 42% of patients required secondary interventions. Sac enlargement did not affect patient survival. CONCLUSIONS: Aneurysm sac enlargement occurs in 15% of patients after FBEVAR for PD-TAAs. Elderly patients (>70 years at baseline) and those with type II endoleaks at 1 year may need closer monitoring and secondary interventions to prevent sac enlargement. Despite sac enlargement in some patients, aneurysm-related mortality at 5 years remains low and overall survival was not associated with sac enlargement.

Preoperative risk factors for 1-year mortality in patients undergoing fenestrated endovascular aortic aneurysm repair in the US Aortic Research Consortium.

BACKGROUND: Early survival (1-year) after elective repair of complex abdominal aortic aneurysms (AAA) or thoracoabdominal aortic aneurysms (TAAA) can be used as an indicator of successful repair and provides a reasonable countermeasure to the annual rupture risk based on diameter. We aimed to identify preoperative factors associated with 1-year mortality after fenestrated or branched endovascular aortic repair (F/BEVAR) and develop a predictive model for 1-year mortality based on patient-specific risk profiles. METHODS: The US-Aortic Research Consortium database was queried for all patients undergoing elective F/BEVAR for complex AAA (cAAA) or TAAA from 2005 to 2022. The primary outcome was 1-year survival based on preoperative risk profile. Multivariable Cox regression was used to determine preoperative variables associated with 1-year mortality overall and by extent of aortic pathology. Logistic regression was performed to build a predictive model for 1-year mortality based on number of risk factors present. RESULTS: A total of 2099 patients met the inclusion criteria for this study (cAAA: n = 709 [34.3%]; type 1-3 TAAA: n = 777 [37.6%]; type 4-5 TAAA: n = 580 [28.1%]). Multivariable Cox regression identified the following significant risk factors associated with 1-year mortality: current smoker, chronic obstructive pulmonary disease, congestive heart failure (CHF), aortic diameter >7 cm, age >75 years, extent 1-3, creatinine >1.7 mg/dL, and hematocrit <36%. When stratified by extent of aortic involvement, multivariable Cox regression revealed risk factors for 1-year mortality in cAAA (CHF maximum aortic diameter >7 cm, hematocrit <36 mg/dL, and current smoking status), type 1-3 TAAA (chronic obstructive pulmonary disease, CHF, and age >75 years), and type 4-5 TAAA (age >75 years, creatinine >1.7 mg/dL, and hematocrit <36 mg/dL). Logistic regression was then used to develop a predictive model for 1-year mortality based on patient risk profile. Appraisal of the model revealed an area under the curve of 0.64 (P < .001), and an observed to expected ratio of 0.85. CONCLUSIONS: This study describes multiple risk factors associated with an increase in 1-year mortality after F/BEVAR. Given that elective repair of cAAA or TAAA is offered to some patients in whom future rupture risk outweighs operative risk, these findings suggest that highly comorbid patients with smaller aneurysms may not benefit from repair. Descriptive and predictive models for 1-year mortality based on patient risk profiles can serve as an adjunct in clinical decision-making when considering elective F/BEVAR.

Practice patterns of antiplatelet and anticoagulant therapy after fenestrated/branched endovascular aortic repair.

OBJECTIVE: Antiplatelet and/or anticoagulant therapy are commonly prescribed after fenestrated/branched endovascular aortic repair (F/BEVAR). However, the optimal regimen remains unknown. We sought to characterize practice patterns and outcomes of antiplatelet and anticoagulant use in patients who underwent F/BEVAR. METHODS: Consecutive patients enrolled (2012-2023) as part of the United States Aortic Research Consortium (US-ARC) from 10 independent physician-sponsored investigational device exemption studies were evaluated. The cohort was characterized by medication regimen on discharge from index F/BEVAR: (1) Aspirin alone OR P2Y12 alone (single-antiplatelet therapy [SAPT]); (2) Anticoagulant alone; (3) Aspirin + P2Y12 (dual-antiplatelet therapy [DAPT]); (4) Aspirin + anticoagulant OR P2Y12 + anticoagulant (SAPT + anticoagulant); (5) Aspirin + P2Y12 + anticoagulant (triple therapy [TT]); and (6) No therapy. Kaplan-Meier analysis and Cox proportional hazards modeling were used to compare 1-year outcomes including survival, target artery patency, freedom from bleeding complication, freedom from all reinterventions, and freedom from stent-specific reintervention. RESULTS: Of the 1525 patients with complete exposure and outcome data, 49.6% were discharged on DAPT, 28.8% on SAPT, 13.6% on SAPT + anticoagulant, 3.2% on TT, 2.6% on anticoagulant alone, and 2.2% on no therapy. Discharge medication regimen was not associated with differences in 1-year survival, bleeding complications, composite reintervention rate, or stent-specific reintervention rate. However, there was a significant difference in 1-year target artery patency. On multivariable analysis comparing with SAPT, DAPT conferred a lower hazard of loss of target artery patency (hazard ratio [HR], 0.48; 95% confidence interval [CI], 0.27-0.84; P = .01). On sub-analyses of renal stents alone or visceral stents alone, DAPT no longer had a significantly lower hazard of loss of target artery patency (renal: HR, 0.66; 95% CI, 0.35-1.27; P = .22; visceral: HR, 0.31; 95% CI, 0.05-1.9; P = .21). Lastly, duration of DAPT therapy (1 month, 6 months, or 1 year) did not significantly affect target artery patency. CONCLUSIONS: Practice patterns for antiplatelet and anticoagulant regimens after F/BEVAR vary widely across the US-ARC. There were no differences in bleeding complications, survival or reintervention rates among different regimens, but higher branch vessel patency was noted in the DAPT cohort. These data suggest there is a benefit in DAPT therapy. However, the generalizability of this finding is limited by the retrospective nature of this data, and the clinical significance of this finding is unclear, as there is no difference in survival, bleeding, or reintervention rates amongst the different regimens. Hence, an "optimal" regimen, including the duration of such regimen, could not be clearly discerned. This suggests equipoise for a randomized trial, nested within this cohort, to identify the most effective antiplatelet/anticoagulant regimen for the growing number of patients being treated globally with F/BEVAR.

Prospective randomized pilot trial comparing prophylactic and therapeutic cerebrospinal fluid drainage during complex endovascular thoracoabdominal aortic aneurysm repair.

BACKGROUND: Endovascular techniques have transformed the management of thoracoabdominal aortic aneurysms (TAAAs). However, spinal cord ischemia (SCI) remains a prevalent and devastating complication. Prophylactic drainage of cerebrospinal fluid (CSF) is among the proposed strategies for prevention of SCI. Although prophylactic CSF drainage is widely used and conceptually attractive, prophylactic CSF drains have not been demonstrated to definitively prevent the occurrence nor mitigate the severity of SCI in endovascular TAAA repair. Whether or not outcomes of prophylactic drains are superior to therapeutic drains remains unknown. This pilot study was performed to determine the feasibility of a randomized clinical trial designed to investigate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair using branched and fenestrated endovascular aortic repair (FBEVAR). METHODS: This was a prospective multicenter randomized pilot clinical trial conducted at The University of Alabama at Birmingham and The University of Massachusetts. Twenty patients were enrolled and randomized to either the prophylactic drainage or therapeutic drainage groups, prior to undergoing FBEVAR for extensive TAAAs and arch aortic aneurysms. This was a pilot feasibility study that was not powered to detect statistical differences in clinical outcomes. The primary outcome was feasibility of randomization and compliance with a shared lumbar drain protocol. Secondary outcomes included rate of drain complications and SCI. RESULTS: Twenty patients were enrolled and successfully randomized, without any crossovers, to either the control cohort (n = 10), without prophylactic drains, or the experimental cohort (n = 10), with prophylactic drains. There were no differences in age, comorbidities, or history of prior aortic surgery across the cohorts. All patients were treated with FBEVAR. Aneurysm classifications were as follows: Extent I (10%), Extent II (50%), Extent III (35%), and Extent IV (5%). The average length of aortic coverage was 207 ± 21.6 mm. The length of aortic coverage did not vary across cohorts, nor did procedural times or blood loss volume. Compliance with the SCI prevention protocol was 100% across both groups. Within the prophylactic drain cohort, one patient experienced an adverse event related to lumbar drain placement, manifested as an epidural hematoma requiring laminectomy, without neurologic deficit (n = 1/10; 10%). There was one SCI event (n = 1/20; 5%), which occurred in the prophylactic drain cohort on postoperative day 9 following an episode of hypotension related to a gastrointestinal bleed. CONCLUSIONS: The role of prophylactic CSF drains for the prevention of SCI following endovascular TAAA repair is a topic of ongoing research, with many current practices based on expert opinion and experience, rather than rigorous scientific data. This study demonstrates the feasibility of a multicenter randomized clinical trial to evaluate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair.

Predictors of amputation-free survival and wound healing after infrainguinal bypass with alternative conduits.

OBJECTIVE: Inadequate vein quality or prior harvest precludes use of autologous single segment greater saphenous vein (ssGSV) in many patients with chronic limb-threatening ischemia (CLTI). Predictors of patient outcome after infrainguinal bypass with alternative (non-ssGSV) conduits are not well-understood. We explored whether limb presentation, bypass target, and conduit type were associated with amputation-free survival (AFS) after infrainguinal bypass using alternative conduits. METHODS: A single-center retrospective study (2013-2020) was conducted of 139 infrainguinal bypasses performed for CLTI with cryopreserved ssGSV (cryovein) (n = 71), polytetrafluoroethylene (PTFE) (n = 23), or arm/spliced vein grafts (n = 45). Characteristics, Wound, Ischemia, and foot Infection (WIfI) stage, and outcomes were recorded. Multivariable Cox proportional hazards and classification and regression tree analysis modeled predictors of AFS. RESULTS: Within 139 cases, the mean age was 71 years, 59% of patients were male, and 51% of cases were nonelective. More patients undergoing bypass with cryovein were WIfI stage 4 (41%) compared with PTFE (13%) or arm/spliced vein (27%) (P = .04). Across groups, AFS at 2 years was 78% for spliced/arm, 79% for PTFE, and 53% for cryovein (adjusted hazard ratio for cryovein, 2.5; P = .02). Among cases using cryovein, classification and regression tree analysis showed that WIfI stage 3 or 4, age >70 years, and prior failed bypass were predictive of the lowest AFS at 2 years of 36% vs AFS of 58% to 76% among subgroups with less than two of these factors. Although secondary patency at 2 years was worse in the cryovein group (26% vs 68% and 89% in arm/spliced and PTFE groups; P < .01), in patients with tissue loss there was no statistically significant difference in wound healing in the cryovein group (72%) compared with other bypass types (72% vs 87%, respectively; P = .12). CONCLUSIONS: In patients with CLTI lacking suitable ssGSV, bypass with autogenous arm/spliced vein or PTFE has superior AFS compared with cryovein, although data were limited for PTFE conduits for distal targets. Despite poor patency with cryovein, wound healing is achieved in a majority of cases, although it should be used with caution in older patients with high WIfI stage and prior failed bypass, given the low rates of AFS.

Secondary interventions following open vs endovascular revascularization for chronic limb threatening ischemia in the BEST-CLI trial.

OBJECTIVES: Patients undergoing revascularization for chronic limb-threatening ischemia experience a high burden of target limb reinterventions. We analyzed data from the Best Endovascular versus Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI) randomized trial comparing initial open bypass (OPEN) and endovascular (ENDO) treatment strategies, with a focus on reintervention-related study endpoints. METHODS: In a planned secondary analysis, we examined the rates of major reintervention, any reintervention, and the composite of any reintervention, amputation, or death by intention-to-treat assignment in both trial cohorts (cohort 1 with suitable single-segment great saphenous vein [SSGSV], n = 1434; cohort 2 lacking suitable SSGSV, n = 396). We also compared the cumulative number of major and all index limb reinterventions over time. Comparisons between treatment arms within each cohort were made using univariable and multivariable Cox regression models. RESULTS: In cohort 1, assignment to OPEN was associated with a significantly reduced hazard of a major limb reintervention (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.28-0.49; P < .001), any reintervention (HR, 0.63; 95% CI, 0.53-0.75; P < .001), or any reintervention, amputation, or death (HR, 0.68; 95% CI, 0.60-0.78; P < .001). Findings were similar in cohort 2 for major reintervention (HR, 0.53; 95% CI, 0.33-0.84; P = .007) or any reintervention (HR, 0.71; 95% CI, 0.52-0.98; P = .04). In both cohorts, early (30-day) limb reinterventions were notably higher for patients assigned to ENDO as compared with OPEN (14.7% vs 4.5% of cohort 1 subjects; 16.6% vs 5.6% of cohort 2 subjects). The mean number of major (mean events per subject ratio [MR], 0.45; 95% CI, 0.34-0.58; P < .001) or any target limb reinterventions (MR, 0.67; 95% CI, 0.57-0.80; P < .001) per year was significantly less in the OPEN arm of cohort 1. The mean number of reinterventions per limb salvaged per year was lower in the OPEN arm of cohort 1 (MR, 0.45; 95% CI, 0.35-0.57; P < .001 and MR, 0.66; 95% CI, 0.55-0.79; P < .001 for major and all, respectively). The majority of index limb reinterventions occurred during the first year following randomization, but events continued to accumulate over the duration of follow-up in the trial. CONCLUSIONS: Reintervention is common following revascularization for chronic limb-threatening ischemia. Among patients deemed suitable for either approach, initial treatment with open bypass, particularly in patients with available SSGSV conduit, is associated with a significantly lower number of major and minor target limb reinterventions.

Relevance of BEST-CLI trial endpoints in a tertiary care limb preservation program.

OBJECTIVE: Major adverse limb event-free survival (MALE-FS) differed significantly by initial revascularization approach in the BEST-CLI randomized trial. The BEST-CLI trial represented a highly selected subgroup of patients seen in clinical practice; thus, we examined the endpoint of MALE-FS in an all-comers tertiary care practice setting. METHODS: This is a single-center retrospective study of consecutive, unique patients who underwent technically successful infrainguinal revascularization for chronic limb-threatening ischemia (2011-2021). MALE was major amputation (transtibial or above) or major reintervention (new bypass, open bypass revision, thrombectomy, or thrombolysis). RESULTS: Among 469 subjects, the mean age was 70 years, and 34% were female. Characteristics included diabetes (68%), end-stage renal disease (ESRD) (16%), Wound, Ischemia, and foot Infection (WIfI) stage 4 (44%), Global Limb Anatomic Staging System (GLASS) stage 3 (62%), and high pedal artery calcium score (pMAC) (22%). Index revascularization was autogenous vein bypass (AVB) (30%), non-autogenous bypass (NAB) (13%), or endovascular (ENDO) (57%). The composite endpoint of MALE or death occurred in 237 patients (51%) at a median time of 189 days from index revascularization. In an adjusted Cox model, factors independently associated with MALE or death included younger age, ESRD, WIfI stage 4, higher GLASS stage, and moderate-severe pMAC, whereas AVB was associated with improved MALE-FS. Freedom from MALE-FS, MALE, and major amputation at 30 days were 90%, 92%, and 95%; and at 1 year were 63%, 70%, and 83%, respectively. MALE occurred in 144 patients (31%) and was associated with ESRD, WIfI stage, GLASS stage, pMAC score, and index revascularization approach. AVB had superior durability, with adjusted 2-year freedom from MALE of 72%, compared with 66% for ENDO and 51% for NAB. Within the AVB group, spliced vein conduit had higher MALE compared with single-segment vein (hazard ratio, 1.8; 95% confidence interval, 0.9-3.7; P = .008 after inverse propensity weighting), but there was no statistically significant difference in major amputation. Of the 144 patients with any MALE, the first MALE was major reintervention in 47% and major amputation in 53%. Major amputation as first MALE was associated with non-AVB index approach. Indications for major reintervention were symptomatic stenosis/occlusion (54%), lack of clinical improvement (28%), asymptomatic graft stenosis (16%), and iatrogenic events (3%). Conversion to bypass occurred after 6% of ENDO cases, two-thirds of which involved distal bypass targets at the ankle or foot. CONCLUSIONS: In this consecutive, all-comers cohort, disease complexity was associated with procedural selection and MALE-FS. AVB independently provided the greatest MALE-FS and freedom from MALE and major amputation. Compared with the BEST-CLI randomized trial, MALE after ENDO in this series was more frequently major amputation, with relatively few conversions to open bypass.

Decreasing prevalence of centers meeting the Society for Vascular Surgery abdominal aortic aneurysm guidelines in the United States.

OBJECTIVE: Based on data supporting a volume-outcome relationship in elective aortic aneurysm repair, the Society of Vascular Surgery (SVS) guidelines recommend that endovascular aortic repair (EVAR) be localized to centers that perform ≥10 operations annually and have a perioperative mortality and conversion-to-open rate of ≤2% and that open aortic repair (OAR) be localized to centers that perform ≥10 open aortic operations annually and have a perioperative mortality ≤5%. However, the number and distribution of centers meeting the SVS criteria remains unclear. This study aimed to estimate the temporal trends and geographic distribution of Centers Meeting the SVS Aortic Guidelines (CMAG) in the United States. METHODS: The SVS Vascular Quality Initiative was queried for all OAR, aortic bypasses, and EVAR from 2011 to 2019. Annual OAR and EVAR volume, 30-day elective operative mortality for OAR or EVAR, and EVAR conversion-to-open rate for all centers were calculated. The SVS guidelines for OAR and EVAR, individually and combined, were applied to each institution leading to a CMAG designation. The proportion of CMAGs by region (West, Midwest, South, and Northeast) were compared by year using a χ2 test. Temporal trends were estimated using a multivariable logistic regression for CMAG, adjusting by region. RESULTS: Overall, 67,865 patients (49,264 EVAR; 11,010 OAR; 7591 aortic bypasses) at 336 institutions were examined. The proportion of EVAR CMAGs increased nationally by 1.7% annually from 51.6% (n = 33/64) in 2011 to 67.1% (n = 190/283) in 2019 (ß = .05; 95% confidence interval [CI], 0.01-0.09; P = .02). The proportion of EVAR CMAGs across regions ranged from 27.3% to 66.7% in 2011 to 63.9% to 72.9% in 2019. In contrast, the proportion of OAR CMAGs has decreased nationally by 1.8% annually from 32.8% (n = 21/64) in 2011 to 16.3% (n = 46/283) in 2019 (ß = -.14; 95% CI, -0.19 to -0.10; P < .01). Combined EVAR and OAR CMAGs were even less frequent and decreased by 1.5% annually from 26.6% (n = 17/64) in 2011 to 13.1% (n = 37/283) in 2019 (ß = -.12; 95% CI, -0.17 to -0.07; P < .01). In 2019, there was no significant difference in regional variation of the proportion of combined EVAR and OAR CMAGs (P = .82). CONCLUSIONS: Although an increasing proportion of institutions nationally meet the SVS guidelines for EVAR, a smaller proportion meet them for OAR, with a concerning downward trend. These data question whether we can safely offer OAR at most institutions, have important implications about sufficient OAR exposure for trainees, and support regionalization of OAR.

Descending thoracic aortic mural ulceration is associated with postoperative spinal cord ischemia after branched endovascular aortic aneurysm repair.

OBJECTIVE: Paraplegia is one of the most feared complications after thoracoabdominal aortic aneurysm repair. The purpose of this study is to determine whether aortic thrombus characteristics are associated with spinal cord ischemia (SCI) after branched endovascular aneurysm repair (BEVAR). METHODS: From April 2011 to April 2020, 62 patients underwent elective BEVAR for thoracoabdominal aortic aneurysm and pararenal aortic aneurysms using a low-profile device and had a complete preoperative computed tomography angiography of the aorta from the sinotubular junction to the aortic bifurcation. Aortic thrombus was evaluated for thrombus thickness ≥5 mm, thrombus >2/3 of aortic circumference, and the presence of an ulcer-like thrombus. One point was assigned at each 5 mm axial image if all 3 criteria were met, resulting in a total "shaggy score" for the entire aorta. Data on demographics, procedural details, and outcomes were collected prospectively. All patients underwent a standard spinal cord protection protocol, including routine cerebrospinal fluid drainage. In July 2016, an insulin infusion protocol (IIP) was initiated to maintain postoperative blood glucose levels <120 mg/dL for 48 hours. The primary clinical end point was postoperative SCI. RESULTS: 10 (16%) patients developed postoperative SCI: 6 with transient paraparesis, 2 with persistent paraparesis, and 2 with persistent paraplegia. Patients with SCI were older, had higher shaggy scores, and were less likely to have been on an IIP. There were no significant differences in demographics, aneurysm type, or operative parameters. In a logistic multivariate regression model for SCI, age (odds ratio [OR]: 1.2 [1.1-1.4], P = .02) and shaggy score (OR: 1.2 [1.1-1.4], P = .02) were independently associated with increased risk of SCI, whereas treatment with the IIP was associated with lower risk of SCI (OR: 0.04 [0.006-0.50], P = .05). Of the individual components of the shaggy score, higher descending thoracic aortic ulcer scores were the most strongly associated with postoperative SCI (P = .009). CONCLUSIONS: Preoperative characterization of aortic wall thrombus is an important adjunctive tool for individualized clinical decision-making and patient counseling about the risk of SCI after BEVAR.

Development and Validation of a Novel Preoperative Risk Score to Identify Patients at Risk for Nonhome Discharge after Elective Endovascular Aortic Aneurysm Repair (EVAR).

BACKGROUND: Nonhome discharge (NHD) to a rehabilitation or skilled nursing facility after elective endovascular aortic repair (EVAR) is uncommon. However, NHD after surgery has an important impact on patient quality of life and postdischarge outcomes. Understanding factors that put patients undergoing EVAR at high risk for NHD is essential to providing adequate preoperative counseling and shared decision making. This study aimed to identify independent predictors of NHD following elective EVAR and to create a clinically useful preoperative risk score. METHODS: Elective EVAR cases were queried from the Society for Vascular Surgery Vascular Quality Initiative 2014-2018. A risk score was created by splitting the data set into two-thirds for development and one-third for validation. A parsimonious stepwise hierarchical multivariable logistic regression controlling for hospital level variation was performed in the development dataset, and the beta-coefficients were used to assign points for a risk score. The score was then validated, and model performance assessed. RESULTS: Overall, 24,426 patients were included and 932 (3.8%) required NHD. Multivariable analysis in the development group identified independent predictors of NHD, which were used to create a 20-point risk score. Patients were stratified into 3 groups based upon their risk score: low risk (0-7 points; n = 16,699) with an NHD rate of 1.8%, moderate risk (8-13 points; n = 7,315) with an NHD rate of 7.3%, and high risk (≥14 points; n = 412) with an NHD rate of 21.8%. The risk score had good predictive ability with c-statistic = 0.75 for model development and c-statistic = 0.73 in the validation dataset. CONCLUSIONS: This novel risk score can predict NHD following EVAR using characteristics that can be identified preoperatively. Utilization of this score may allow for improved risk assessment, preoperative counseling, and shared decision making.

Risk factors and associated outcomes of postoperative delirium after open abdominal aortic aneurysm repair.

OBJECTIVE: Open abdominal aortic aneurysm repair (OAR) is a major vascular procedure that incurs a large physiologic demand, increasing the risk for complications such as postoperative delirium (POD). We sought to characterize POD incidence, identify delirium risk factors, and evaluate the effect of delirium on postoperative outcomes. We hypothesized that POD following OAR would be associated with increased postoperative complications and resource utilization. METHODS: This was a retrospective study of all OAR cases from 2012 to 2020 at a single tertiary care center. POD was identified via a validated chart review method based on key words and Confusion Assessment Method assessments. The primary outcome was POD, and secondary outcomes included length of stay, non-home discharge, 90-day mortality, and 1-year survival. Bivariate analysis as appropriate to the data was used to assess the association of delirium with postoperative outcomes. Multivariable binary logistic regression was used to identify risk factors for POD and Cox regression for variables associated with worse 1-year survival. RESULTS: Overall, 198 OAR cases were included, and POD developed in 34% (n = 67). Factors associated with POD included older age (74 vs 69 years; P < .01), frailty (50% vs 28%; P < .01), preoperative dementia (100% vs 32%; P < .01), symptomatic presentation (47% vs 27%; P < .01), preoperative coronary artery disease (44% vs 28%; P = .02), end-stage renal disease (89% vs 32%; P < .01) and Charlson Comorbidity Index score >4 (42% vs 26%; P = .01). POD was associated with 90-day mortality (19% vs 5%; P < .01), non-home discharge (61% vs 30%; P < .01), longer median hospital length of stay (14 vs 8 days; P < .01), longer median intensive care unit length of stay (6 vs 3 days; P < .01), postoperative myocardial infarction (7% vs 2%; P = .045), and postoperative pneumonia (19% vs 8%; P = .01). On multivariable analysis, risk factors for POD included older age, history of end-stage renal disease, lack of epidural, frailty, and symptomatic presentation. A Cox proportional hazards model revealed that POD was associated with worse survival at 1 year (hazard ratio, 3.8; 95% confidence interval, 1.6-9.0; P = .003). CONCLUSIONS: POD is associated with worse postoperative outcomes and increased resource utilization. Future studies should examine the role of improved screening, implementation of delirium prevention bundles, and multidisciplinary care for the most vulnerable patients undergoing OAR.

Measurement of Abdominal Aortic Aneurysm Strain Using MR Deformable Image Registration: Accuracy and Relationship to Recent Aneurysm Progression.

BACKGROUND: Management of asymptomatic abdominal aortic aneurysm (AAA) based on maximum aneurysm diameter and growth rate fails to preempt many ruptures. Assessment of aortic wall biomechanical properties may improve assessment of progression and rupture risk. This study aimed to assess the accuracy of AAA wall strain measured by cine magnetic resonance imaging (MRI) deformable image registration (MR strain) and investigate its relationship with recent AAA progression. METHODS: The MR strain accuracy was evaluated in silico against ground truth strain in 54 synthetic MRIs generated from a finite element model simulation of an AAA patient's abdomen for different aortic pulse pressures, tissue motions, signal intensity variations, and image noise. Evaluation included bias with 95% confidence interval (CI) and correlation analysis. Association of MR strain with AAA growth rate was assessed in 25 consecutive patients with >6 months of prior surveillance, for whom cine balanced steady-state free-precession imaging was acquired at the level of the AAA as well as the proximal, normal-caliber aorta. Univariate and multivariate regressions were used to associate growth rate with clinical variables, maximum AAA diameter (Dmax), and peak circumferential MR strain through the cardiac cycle. The MR strain interoperator variability was assessed using bias with 95% CI, intraclass correlation coefficient, and coefficient of variation. RESULTS: In silico experiments revealed an MR strain bias of 0.48% ± 0.42% and a slope of correlation to ground truth strain of 0.963. In vivo, AAA MR strain (1.2% ± 0.6%) was highly reproducible (bias ± 95% CI, 0.03% ± 0.31%; intraclass correlation coefficient, 97.8%; coefficient of variation, 7.14%) and was lower than in the nonaneurysmal aorta (2.4% ± 1.7%). Dmax (ß = 0.087) and MR strain (ß= -1.563) were both associated with AAA growth rate. The MR strain remained an independent factor associated with growth rate (ß= -0.904) after controlling for Dmax. CONCLUSIONS: Deformable image registration analysis can accurately measure the circumferential strain of the AAA wall from standard cine MRI and may offer patient-specific insight regarding AAA progression.

Outcomes of Elective and Non-elective Fenestrated-branched Endovascular Aortic Repair for Treatment of Thoracoabdominal Aortic Aneurysms.

OBJECTIVE: To describe outcomes after elective and non-elective fenestrated-branched endovascular aortic repair (FB-EVAR) for thoracoabdominal aortic aneurysms (TAAAs). BACKGROUND: FB-EVAR has been increasingly utilized to treat TAAAs; however, outcomes after non-elective versus elective repair are not well described. METHODS: Clinical data of consecutive patients undergoing FB-EVAR for TAAAs at 24 centers (2006-2021) were reviewed. Endpoints including early mortality and major adverse events (MAEs), all-cause mortality, and aortic-related mortality (ARM), were analyzed and compared in patients who had non-elective versus elective repair. RESULTS: A total of 2603 patients (69% males; mean age 72±10 year old) underwent FB-EVAR for TAAAs. Elective repair was performed in 2187 patients (84%) and non-elective repair in 416 patients [16%; 268 (64%) symptomatic, 148 (36%) ruptured]. Non-elective FB-EVAR was associated with higher early mortality (17% vs 5%, P <0.001) and rates of MAEs (34% vs 20%, P <0.001). Median follow-up was 15 months (interquartile range, 7-37 months). Survival and cumulative incidence of ARM at 3 years were both lower for non-elective versus elective patients (50±4% vs 70±1% and 21±3% vs 7±1%, P <0.001). On multivariable analysis, non-elective repair was associated with increased risk of all-cause mortality (hazard ratio, 1.92; 95% CI] 1.50-2.44; P <0.001) and ARM (hazard ratio, 2.43; 95% CI, 1.63-3.62; P <0.001). CONCLUSIONS: Non-elective FB-EVAR of symptomatic or ruptured TAAAs is feasible, but carries higher incidence of early MAEs and increased all-cause mortality and ARM than elective repair. Long-term follow-up is warranted to justify the treatment.

Update of T-branch use from the US Aortic Research Consortium.

Aortic endograft evolution has altered our approach to treating patients with both standard and complex aortic disease. In particular, fenestrated and branched aortic endografts have allowed for the expansion of therapy to include those patients with extensive thoracoabdominal aortic aneurysms (TAAAs). The fenestrations and branches allow for the aortic endografts to achieve a seal in the proximal and distal aspects of the aorto-iliac tree, to exclude the aneurysm, while maintaining perfusion to the renal and visceral vessels. Historically, many of the grafts used for this purpose are custom made devices designed for a specific patient based on their preoperative computed tomography imaging. One downside to this approach is the time it takes to construct these grafts. Given this, much effort has been directed towards developing "off-the-shelf" grafts which may be applicable to many patients in an immediate-need bases. The Zenith T-Branch device offers an off-the-shelf graft with four directional branches. Its utilization is not applicable to all patients, but can be applied to many patients with TAAAs. Large reported series on outcomes for these devices is limited to centers in Europe as well as within the United States Aortic Research Consortium. While early outcomes appear excellent, long-term outcomes related to aneurysm exclusion, branch patency, and freedom from reintervention are needed and will be forthcoming.

Severity of acute kidney injury is associated with decreased survival after fenestrated and branched endovascular aortic aneurysm repair.

OBJECTIVE: Acute kidney injury (AKI) occurs frequently in complex aortic surgery and has been implicated in perioperative and long-term survival. This study sought to characterize the relationship between AKI severity and mortality after fenestrated and branched endovascular aortic aneurysm repair (F/B-EVAR). METHODS: Consecutive patients enrolled by the US Aortic Research Consortium in 10, prospective, nonrandomized, physician-sponsored investigational device exemption studies evaluating F/B-EVAR, between 2005 and 2023, were included in this study. Perioperative AKI during hospitalization was defined by and staged using the 2012 Kidney Disease Improving Global Outcomes criteria. Determinants of AKI were evaluated with backward stepwise mixed effects multivariable ordinal logistic regression. Survival was analyzed with conditionally adjusted survival curves and backward stepwise mixed effects Cox proportional hazards modelling. RESULTS: In the study period, 2413 patients with a median (interquartile range [IQR]) age of 74 years (IQR, 69-79 years) underwent F/B-EVAR. The median follow-up duration was 2.2 years (IQR, 0.7-3.7 years). The median baseline estimated glomerular filtration rate (eGFR) and creatinine were 68 mL/min/1.73 m2 (IQR, 53-84 mL/min/1.73 m2) and 1.1 mg/dL (IQR, 0.9-1.3 mg/dL), respectively. Stratification of AKI identified 316 patients (13%) with stage 1 injury, 42 (2%) with stage 2 injury, and 74 (3%) with stage 3 injury. Renal replacement therapy was initiated during the index hospitalization in 36 patients (1.5% of cohort, 49% of stage 3 injuries). Thirty-day major adverse events were associated with AKI severity (all P ≤ .0001). Multivariable predictors of AKI severity included baseline eGFR (proportional odds ratio, 0.9 per 10 mL/min/1.73 m2 [95% confidence interval (CI), 0.85-0.95 per 10 mL/min/1.73 m2]; P < .0001), baseline serum hematocrit (0.58 per 10% [95% CI, 0.48-0.71 per 10%]; P < .0001), renal artery technical failure during aneurysm repair (3 [95% CI,1.61-5.72]; P = .0006), and total operating time (1.05 per 10 minutes [95% CI, 1.04-1.07 per 10 minutes]; P < .0001). One-year unadjusted survivals for AKI severity strata were 91% (95% CI, 90%-92%) for no injury, 80% (95% CI, 76%-85%) for stage 1 injury, 72% (95% CI, 59-87%) for stage 2 injury, and 46% (95% CI, 35-59%) for stage 3 injury (P<.0001). Multivariable determinants of survival included AKI severity (stage 1, hazard ratio [HR], 1.6 [95% CI, 1.3-2]); stage 2, HR, 2.2 [95% CI, 1.4-3.4]); stage 3 HR, 4 [95% CI, 2.9-5.5]; P < .0001), decreased eGFR (HR, 1.1 [95% CI, 0.9-1.3]; P = .4), patient age (HR, 1.6 per 10 years [95% CI, 1.4-1.8 per 10 years]; P < .0001), baseline chronic obstructive pulmonary disease (HR, 1.5 [95% CI, 1.3-1.8]; P < .0001), baseline congestive heart failure (HR, 1.7 [95% CI, 1.6-2.1]; P < .0001), postoperative paraplegia (HR, 2.1 [95% CI, 1.1-4]; P = .02), and procedural technical success (HR, 0.6 [95% CI, 0.4-0.8]; P = .003). CONCLUSIONS: AKI, as defined by the 2012 Kidney Disease Improving Global Outcomes criteria, occurred in 18% of patients after F/B-EVAR. Greater severity of AKI after F/B-EVAR was associated with decreased postoperative survival. The predictors of AKI severity identified in these analyses suggest a role for improved preoperative risk mitigation and staging of interventions in complex aortic repair.

Mid-term Renal and Mesenteric Artery Outcomes During Fenestrated and Branched Endovascular Aortic Repair for Complex Abdominal and Thoracoabdominal Aortic Aneurysms in the United States Aortic Research Consortium.

OBJECTIVE: To report mid-term outcomes of renal-mesenteric target arteries (TAs) after fenestrated-branched endovascular aortic repair (FB-EVAR) of complex abdominal and thoracoabdominal aortic aneurysm. BACKGROUND: TA instability (TAI) is the most frequent indication for reintervention after FB-EVAR. METHODS: Data from consecutive patients enrolled in 9 prospective nonrandomized physician-sponsored investigational device exemption studies between 2005 and 2020 were reviewed. TA outcomes through 5 years of follow-up were analyzed for vessels incorporated by fenestrations or directional branches (DBs), including TA patency, endoleak, integrity failure, reintervention, and instability. RESULTS: A total of 1681 patients had 6349 renal-mesenteric arteries were targeted using 3720 fenestrations (59%), 2435 DBs (38%), and 194 scallops (3%). Mean follow was 23 ± 21 months. At 5 years, TAs incorporated by fenestrations had higher primary (95 ± 1% vs 91 ± 1%, P < 0.001) and secondary patency (98 ± 1% vs 94 ± 1%, P < 0.001), and higher freedom from TAI (87 ± 2% vs 84 ± 2%, P = 0.002) compared with TAs incorporated by DBs, with no differences in other TA events. DBs targeted by balloon-expandable stent-grafts had significantly lower freedom from TAI (78 ± 4% vs 88 ± 1%, P = 0.006), TA endoleak (87 ± 3% vs 97 ± 1%, P < 0.001), and TA reintervention (83 ± 4% vs 95 ± 1%, P < 0.001) compared with those targeted by self-expandable stent-grafts. CONCLUSIONS: Incorporation of renal and mesenteric TA during FB-EVAR is safe and durable with high 5-year patency rates and low freedom from TAI. DBs have lower patency rates and lower freedom from TAI than fenestrations, with better performance for self-expandable stent grafts as compared with balloon-expandable stent grafts.

Predictors and outcomes of spinal cord injury following complex branched/fenestrated endovascular aortic repair in the US Aortic Research Consortium.

OBJECTIVE: Spinal cord ischemia (SCI) is a well-known complication of thoracoabdominal aortic aneurysm repair and is associated with profound morbidity and mortality. The purpose of this study was to describe predictors for the development of SCI, as well as outcomes for patients who develop SCI, after branched/fenestrated endovascular aortic repair in a large cohort of centers with adjudicated physician-sponsored investigational device exemption studies. METHODS: We used a pooled dataset from nine US Aortic Research Consortium centers involved in investigational device exemption trials for treatment of suprarenal and thoracoabdominal aortic aneurysms. SCI was defined as new transient weakness (paraparesis) or permanent paraplegia after repair without other potential neurological etiologies. Multivariable analysis was performed to identify predictors of SCI, and life-table analysis and Kaplan-Meier methodologies were used to evaluate survival differences. RESULTS: A total of 1681 patients underwent branched/fenestrated endovascular aortic repair from 2005 to 2020. The overall rate of SCI was 7.1% (3.0% transient and 4.1% permanent). Predictors of SCI on multivariable analysis were Crawford Extent I, II, and III distribution of aortic disease (odds ratio [OR], 4.79; 95% confidence interval [CI], 4.77-4.81; P < .001), age ≥70 years (OR, 1.64; 95% CI, 1.63-1.64; P = .029), packed red blood cell transfusion (OR, 2.00; 95% CI, 1.99-2.00; P = .001), and a history of peripheral vascular disease (OR, 1.65; 95% CI, 1.64-1.65; P = .034). The median survival was significantly worse for patients with any degree of SCI compared with those without SCI (any SCI, 40.4 vs no SCI, 60.3 months; log-rank P < .001), and also worse in those with a permanent deficit (24.1 months) vs those with a transient deficit (62.4 months) (log-rank P < .001). The 1-year survival for patients who developed no SCI was 90.8%, compared with 73.9% in patients who developed any SCI. When stratified by degree of deficit, survival was 84.8% at 1 year for those who developed paraparesis and 66.2% for those who developed permanent deficits. CONCLUSIONS: The overall rates of any SCI at 7.1% and permanent deficit at 4.1% observed in this study compare favorably with those reported in contemporary literature. Our findings confirm that increased length of aortic disease is associated with SCI and those with Crawford Extent I to III thoracoabdominal aortic aneurysms are at highest risk. The long-term impact on patient mortality underscores the importance of preventive measures and rapid implementation of rescue protocols if and when deficits develop.

Effect of bridging stent graft selection for directional branches on target artery outcomes of fenestrated-branched endovascular aortic repair in the United States Aortic Research Consortium.

OBJECTIVE: The purpose of this study was to evaluate the effect of directional branches (DBs) bridging stent choice on target artery (TA) outcomes during fenestrated-branched endovascular repair of complex abdominal and thoracoabdominal aortic aneurysms. METHODS: Patients enrolled in nine prospective physician-sponsored investigational device exemption studies in the United States between 2005 and 2020 were analyzed. All patients who had at least one TA incorporated by DB using either self-expandable (SESGs), balloon-expandable (BESGs), or hybrid stent graft combinations (HSGs). Endpoints were TA patency and freedom from TA endoleak, instability, and reintervention. RESULTS: There were 800 patients with 2426 renal-mesenteric arteries incorporated by DBs. DB stent selection was SESGs in 1205 TAs (50%), BESGs in 1095 TAs (45%), and HSGs in 126 TAs (5%). SESGs were predominantly used in the first three quartiles of the study period, whereas BESGs comprised 75% of all stents between 2017 and 2020. The median follow-up was 15 months (interquartile range, 6-35 months). At 5 years, BESGs had significantly lower freedom from TA instability (78% ± 4% vs 88% ± 1% vs 96% ± 2%; log-rank P =.010), freedom from TA endoleaks (87% ± 3% vs 97% ± 1% vs 99% ± 1%; log-rank P < .001), and freedom from TA reintervention (83% ± 4% vs 95% ± 1% vs 99% ± 2%; log-rank P <.001) compared with SESGs or HSGs, respectively. For renal arteries, there was no difference in freedom from TA instability for BESGs, SESGs, or HSGs. However, freedom from TA endoleaks and reintervention were lower for renal arteries targeted by BESGs compared with DBs targeted by SESGs and HSGs (83% ± 6% vs 98% ± 1% vs 100%; log-rank P < .001; and 70% ± 10% vs 92% ± 1% vs 96% ± 4%; log-rank P = .022). For mesenteric arteries, DBs targeted by BESGs had lower freedom from TA instability, endoleak, and reintervention than SESGs or HSGs. In stent-specific analysis, iCAST BESGs had the lowest freedom from TA instability either for renal or mesenteric arteries, primarily due to higher rates of TA endoleaks. There was no difference in patency in any scenario. Independent predictors of TA instability were age (+1-year: hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.94-0.99), stent diameter (+1 mm: HR, 0.67; 95% CI, 0.57-0.80), and BESG (HR, 1.8; 95% CI, 1.1-2.9). CONCLUSIONS: DBs incorporated using BESGs had lower freedom from TA instability, TA endoleak, and TA reintervention compared with SESGs and HSGs. The patency of DBs was not affected by the type of stent construction. The observed performance disadvantage associated with BESGs appears to have largely been driven by iCAST usage.

Dynamic Contrast-Enhanced MRI in Abdominal Aortic Aneurysms as a Potential Marker for Disease Progression.

BACKGROUND: Abdominal aortic aneurysms (AAAs) may rupture before reaching maximum diameter (Dmax ) thresholds for repair. Aortic wall microvasculature has been associated with elastin content and rupture sites in specimens, but its relation to progression is unknown. PURPOSE: To investigate whether dynamic contrast-enhanced (DCE) MRI of AAA is associated with Dmax or growth. STUDY TYPE: Prospective. POPULATION: A total of 27 male patients with infrarenal AAA (mean age ± standard deviation = 75 ± 5 years) under surveillance with DCE MRI and 2 years of prior follow-up intervals with computed tomography (CT) or MRI. FIELD STRENGTH/SEQUENCE: A 3-T, dynamic three-dimensional (3D) fast gradient-echo stack-of-stars volumetric interpolated breath-hold examination (Star-VIBE). ASSESSMENT: Wall voxels were manually segmented in two consecutive slices at the level of Dmax . We measured slope to 1-minute and area under the curve (AUC) to 1 minute and 4 minutes of the signal intensity change postcontrast relative to that precontrast arrival, and, Ktrans , a measure of microvascular permeability, using the Patlak model. These were averaged over all wall voxels for association to Dmax and growth rate, and, over left/right and anterior/posterior quadrants for testing circumferential homogeneity. Dmax was measured orthogonal to the aortic centerline and growth rate was calculated by linear fit of Dmax measurements. STATISTICAL TESTS: Pearson correlation and linear mixed effects models. A P value <0.05 was considered statistically significant. RESULTS: In 44 DCE MRIs, mean Dmax was 45 ± 7 mm and growth rate in 1.5 ± 0.4 years of prior follow-up was 1.7 ± 1.2 mm per year. DCE measurements correlated with each other (Pearson r = 0.39-0.99) and significantly differed between anterior/posterior versus left/right quadrants. DCE measurements were not significantly associated with Dmax (P = 0.084, 0.289, 0.054 and 0.255 for slope, AUC at 1 minute and 4 minutes, and Ktrans , respectively). Slope and 4 minutes AUC significantly associated with growth rate after controlling for Dmax . CONCLUSION: Contrast uptake may be increased in lateral aspects of the AAA. Contrast enhancement 1-minute slope and 4-minutes AUC may be associated with a period of recent AAA growth that is independent of Dmax . EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.

Comparison of single- and multistage strategies during fenestrated-branched endovascular aortic repair of thoracoabdominal aortic aneurysms.

OBJECTIVE: The aim of this study was to compare outcomes of single or multistage approach during fenestrated-branched endovascular aortic repair (FB-EVAR) of extensive thoracoabdominal aortic aneurysms (TAAAs). METHODS: We reviewed the clinical data of consecutive patients treated by FB-EVAR for extent I to III TAAAs in 24 centers (2006-2021). All patients received a single brand manufactured patient-specific or off-the-shelf fenestrated-branched stent grafts. Staging strategies included proximal thoracic aortic repair, minimally invasive segmental artery coil embolization, temporary aneurysm sac perfusion and combinations of these techniques. Endpoints were analyzed for elective repair in patients who had a single- or multistage approach before and after propensity score adjustment for baseline differences, including the composite 30-day/in-hospital mortality and/or permanent paraplegia, major adverse event, patient survival, and freedom from aortic-related mortality. RESULTS: A total of 1947 patients (65% male; mean age, 71 ± 8 years) underwent FB-EVAR of 155 extent I (10%), 729 extent II (46%), and 713 extent III TAAAs (44%). A single-stage approach was used in 939 patients (48%) and a multistage approach in 1008 patients (52%). A multistage approach was more frequently used in patients undergoing elective compared with non-elective repair (55% vs 35%; P < .001). Staging strategies were proximal thoracic aortic repair in 743 patients (74%), temporary aneurysm sac perfusion in 128 (13%), minimally invasive segmental artery coil embolization in 10 (1%), and combinations in 127 (12%). Among patients undergoing elective repair (n = 1597), the composite endpoint of 30-day/in-hospital mortality and/or permanent paraplegia rate occurred in 14% of single-stage and 6% of multistage approach patients (P < .001). After adjustment with a propensity score, multistage approach was associated with lower rates of 30-day/in-hospital mortality and/or permanent paraplegia (odds ratio, 0.466; 95% confidence interval, 0.271-0.801; P = .006) and higher patient survival at 1 year (86.9±1.3% vs 79.6±1.7%) and 3 years (72.7±2.1% vs 64.2±2.3%; adjusted hazard ratio, 0.714; 95% confidence interval, 0.528-0.966; P = .029), compared with a single stage approach. CONCLUSIONS: Staging elective FB-EVAR of extent I to III TAAAs was associated with decreased risk of mortality and/or permanent paraplegia at 30 days or within hospital stay, and with higher patient survival at 1 and 3 years.