Postoperative imaging follow-up at 2 years as a predictor of long-term outcomes after endovascular aneurysm repair

Prediction of Aneurysm Sac Shrinkage After Endovascular Aortic Repair Using Machine Learning-Based Decision Tree Analysis

INTRODUCTION

A simple risk stratification model to predict aneurysm sac shrinkagein patients undergoing endovascular aortic repair (EVAR) for abdominal aortic aneurysms (AAA) was developed using machine learning-based decision tree analysis.

METHODS

One hundred nineteen patients with AAA who underwent elective EVAR at Tokyo Medical University Hospital between November 2013 and July 2019 were included in the study. Predictors of aneurysm sac shrinkage identified in univariable analysis (P < 0.05) were entered into the decision tree analysis.

RESULTS

Univariable analysis revealed significant differences between patients with and without aneurysm sac shrinkage in the variables of age (<75 y or ≥75 y), current smoking, operative type II endoleak, and preoperative pulse wave velocity (PWV) (<1800 cm/s or ≥1800 cm/s). The decision tree showed that preoperative PWV was the most relevant predictor, followed by operative type II endoleak and current smoking, and identified 6 terminal nodes with likelihoods of aneurysm sac shrinkage ranging from 5.6% to 63.6%.

CONCLUSIONS

We established a decision tree model with 3 variables (preoperative PWV, operative type II endoleak, and current smoking) to predict aneurysm sac shrinkage in patients undergoing EVAR for AAA. This classification model may help identify patients with a high or low likelihood of aneurysm sac shrinkage.

Open aneurysmorraphy following branched and fenestrated endovascular repair of complex thoracic aneurysms

OBJECTIVE

We present a review of our hybrid management (endovascular + open surgery) of large thoracic aortic aneurysms (>80 mm). The strategy comprises a primary endovascular repair using thoracic endovascular aortic repair (TEVAR), and/or fenestrated and branched endografts (FBEVAR), followed by open thoracotomy and aneurysmorraphy, specifically without the need for aortic cross-clamping.

METHODS

We performed a retrospective review of all patients who had undergone aneurysmorraphy via thoracotomy following TEVAR and FBEVAR in two high-volume aortic centers between December 2017 and March 2024. We performed aneurysmorraphy in two clinical situations: (1) in the setting of a planned staged treatment, shortly after TEVAR or FBEVAR in young patients with aneurysm diameter >100 mm; and (2) as a secondary intervention during follow-up for patients with persistent sac enlargement and aneurysm diameters >80 mm. The primary end points were 30-day survival and aneurysm-related mortality during follow-up. Secondary endpoints were sac size evolution, perioperative and postoperative complications, freedom from further reintervention, and late aortic complications.

RESULTS

Twelve patients underwent aneurysmorraphy following TEVAR and/or FBEVAR during the study period. Mean patient age was 60 ± 12 years, and the mean sac diameter before thoracotomy was 101 ± 25 mm. Endovascular embolization of intercostal arteries prior to aneurysmorraphy was performed in four patients. The 30-day survival rate was 100%. During the mean follow up period of 21 months, two patients died-one of COVID and another of intra-cerebral hemorrhage. No aneurysm-related mortality occurred, and sac regression was achieved in all patients except one experiencing aortic growth below the aneurysmorraphy.

CONCLUSIONS

This study demonstrates that thoracic aneurysmorraphy performed after TEVAR and FBEVAR for complex thoracic aneurysms is a safe and effective technique. This procedure allows the eradication of endoleaks and an immediate sac volume reduction, which prevents aorta-bronchial or esophageal fistulation and secures the endovascular repair; the reduction of the aneurysm mass effect restores normal lung parenchyma expansion. This hybrid management strategy drastically reduces the morbidity associated with standard open surgery performed for thoracic endograft explantation.

Possible implications of device-specific variability in post-endovascular aneurysm repair sac regression and endoleaks for surveillance categorization

OBJECTIVE

Significant sac regression during early surveillance has been shown to best predict reintervention-free long-term surveillance after endovascular aneurysm repair (EVAR). Furthermore, a persistent endoleak has been related to a worse outcome. Individualized surveillance algorithms based on these findings have been suggested. There are no studies comparing the performance of different stent grafts regarding sac regression, the presence of type II endoleaks, and their possible implications for individualized surveillance. The objective of this study was to evaluate device-specific differences and how these may affect patient categorization for surveillance.

METHODS

Patients were treated electively with standard EVAR between 2005 and 2015 using three different devices (Zenith by Cook, Excluder by Gore, and Endurant by Medtronic). The data were reviewed retrospectively until 2020. Patients' computed tomography angiographies (CTAs) at 30 days and at 2 years were analyzed for freedom from endoleaks and for sac regression of ≥5 mm. Reinterventions during long-term surveillance were counted. Patients were categorized according to the presence of any endoleak and sac regression at 30 days and 2 years, and the probability of reintervention-free long-term surveillance was evaluated based on these findings.

RESULTS

A total of 435 patients were treated for an abdominal aortic aneurysm with EVAR during the study period. At 30 days, 80.0% (n = 339) of the patients were free from endoleaks, and at 2 years, 78.9% (n = 273) were free from endoleaks. There was a significant difference in endoleak rate at 30 days and 2 years between the devices (P < .001 and P = .001). There was no significant difference in sac regression between the devices at 2 years (P = .096). The categorization at 30 days based on endoleak status had a sensitivity of 44.9%, specificity of 87.4%, and negative predictive value of 84.1% for finding a reintervention-requiring complication during long-term follow-up. The corresponding figures at 2 years were 63.3%, 91.4%, and 89.4%, respectively. The combination of freedom from endoleaks and sac regression of ≥5 mm in the 2-year CTA best predicted an uneventful long-term surveillance. Patients who met this criterion had a 95.6% probability (negative predictive value) of having a reintervention-free long-term surveillance.

CONCLUSIONS

There are significant differences in the prevalence of endoleaks between devices at 30 days and 2 years, but there is no difference in sac regression. Patients with sac regression of ≥5 mm and no endoleaks in the 2-year CTA can be safely categorized for infrequent surveillance regardless of the stent graft model that has initially been used.

Prophylactic Sac Outflow Vessel Embolization is Associated with Improved Sac Regression in Patients Undergoing Endovascular Aortic Aneurysm Repair

OBJECTIVE

Type II endoleaks (T2E), commonly identified after endovascular aneurysm repair (EVAR), have been associated with late endograft failure and secondary rupture. Number and size of patent aortic aneurysm sac outflow vessels, namely the inferior mesenteric, lumbar, and accessory renal arteries, have been implicated as known risk factors for persistent T2E. Given technical challenges associated with post-EVAR embolization, prophylactic embolization of aortic aneurysm sac outflow vessels has been advocated to prevent T2E; however, current evidence is limited. We sought to examine the effect of concomitant prophylactic aortic aneurysm sac outflow vessels embolization in patients undergoing EVAR.

METHODS

Patients 18 and older in the SVS Vascular Quality Initiative database who underwent elective EVAR for intact aneurysms between January 2009 and November 2020 were included. Patients with history of prior aortic repair and those without available follow-up data were excluded. Patient demographics, operative characteristics, and outcomes were analyzed by group: EVAR with or without prophylactic sac outflow vessel embolization (emboEVAR). Outcomes of interest were rates of in-hospital postoperative complications, incidence of aneurysmal sac regression (≥5mm) and T2E, and rates of re-intervention in follow-up.

RESULTS

15060 patients were included: 272 had emboEVAR and 14788 had EVAR alone. There was no significant difference between groups in terms of age, comorbidities, or anatomic characteristics including mean maximum preoperative aortic diameter (5.5 vs. 5.6 cm, p=0.48). emboEVAR was associated with significantly longer procedural times (148 vs. 124 minutes, p<0.0001), prolonged fluoroscopy (32 vs. 23 minutes, p<0.0001), increased contrast use (105 vs. 91 mL, p<0.0001), without significant reduction in T2E at case completion (17.7% vs. 16.3%, p=0.54). Incidence of postoperative complications (3.7% vs. 4.6%, p=0.56), index hospitalization reintervention rates (0.7% vs. 1.3%, p=0.59), length of stay (1.8 vs. 2 days, p=0.75), and thirty-day mortality (0% vs. 0%, p=1) were similar between groups. In mid-term follow-up (14.6±6.2 months), the emboEVAR group had a significantly greater mean reduction in maximum aortic diameter (0.69 vs. 0.54 cm, p=0.006) with a higher proportion experiencing sac regression ≥5 mm (53.5% vs. 48.7%). Re-intervention rates were similar between groups. On multivariable analysis, prophylactic aortic aneurysm sac outflow vessel embolization (OR 1.34, CI 1.04-1.74, p=0.024) was a significant independent predictor of sac regression.

CONCLUSIONS

Prophylactic sac outflow vessel embolization can be performed safely for patients with intact aortic aneurysms undergoing elective EVAR without significant associated perioperative morbidity or mortality. emboEVAR is associated with significant sac regression compared to EVAR alone in mid-term follow-up. Although there was not a decrease in the incidence of T2E, this technique shows promise and future efforts should focus on identifying a subset of aneurysm and outflow branch characteristics that will benefit from concomitant selective versus complete prophylactic sac outflow vessel embolization.

Survival and durability after endovascular aneurysm repair reflect era-related surgical judgement

OBJECTIVE

Abdominal aortic aneurysm management guidelines from the National Institute for Clinical Excellence in 2020, based heavily on randomized controlled trials in an early era of infrarenal endovascular aneurysm repair (EVAR), suggested that the long-term outcomes after EVAR jeopardize its use in elective abdominal aortic aneurysm repair. We hypothesized that, in a rapidly evolving surgical field, the era of aneurysm repair may have a significant influence on long-term patient outcomes.

METHODS

Using a single-center retrospective cohort design, we identified two EVAR cohorts, the early cohort (n = 166) who underwent EVAR from 2008 to 2010, and a contemporary late cohort (n = 129) from 2015 to 2017. We assessed patient preoperative demographics and era of repair against the primary outcomes of reinterventions, reintervention-free survival, and mortality, addressing their relationships to anatomic selection criteria, graft durability, endoleak, and aneurysm diameter to 5 years after the procedure.

RESULTS

Early cohort patients had decreased reintervention-free survival (early 80.1% vs late 93.3%) and decreased overall survival (early 71.3% vs late 81%) at 3 years and throughout follow-up. The preoperative anatomy judged suitable for EVAR in early cohort patients was more variable than for late cohort patients, including 104% larger proximal and 106% larger distal landing zone diameters, with a mean 11.6-mm shorter length infrarenal aortic and 13.3-mm shorter length iliac sealing zones in the early group. Early cohort patients had more complications during follow-up, including graft kinking and endoleaks, and 24.4% of early vs 8.5% of late patients underwent one or more reinterventions.

CONCLUSIONS

Although technical skill in EVAR implantation may not evolve significantly after a threshold of cases, surgical judgement, relating to anatomic selection and device sizing, requires feedback from long-term sequalae and significantly impacted EVAR outcomes by era. EVAR patients from an early repair era had significantly worse outcomes, with more complications, reinterventions, and a decrease in survival.