Abdominal aortic aneurysm anatomic severity grading score predicts implant-related complications, systemic complications, and mortality

Correlation Between Calcium Scoring and Abdominal Aortic Aneurysm Endovascular Repair Outcomes

OBJECTIVES

Endovascular aneurysm repair, though minimally invasive and has the benefit of relatively low perioperative complication rates, it is associated with significant long term reintervention rates related to endoleaks. Several variables have been studied to predict the outcomes of endovascular aneurysm repair, 1 of which is the calcium burden of the vasculature. This prompted us to study the association between calcium burden measured by the standardized Agatston scoring system and the outcomes of Endovascular aneurysm repair.

METHODS

This is a retrospective study of patients who underwent Endovascular aneurysm repair from 2008 to 2020 at our institution and who had a non-contrast computerized tomography scan preoperatively, accounting for 87 patients. The calcium burden of the vasculature was measured by the Agatston scoring system allowing for better reproducibility, and the outcome variables included mortality and endoleaks.

RESULTS

Patients with higher median total calcium scores (≥12966.9) had significantly lesser survival (79.8% vs 52.3% (P = .002) at five years compared to patients with lower median total calcium score (<12966.9). Also, patients with type 2 endoleaks had higher calcium scores in above the aneurysm level ((1591.2 vs 688.2), P = .05)) compared to patients with no type 2 endoleaks.

CONCLUSION

Calcium score assigned using a standardized Agatston scoring system can be used as a predictor of mortality risk assisting in deciding the treatment of choice for patients.

Outcomes of Endurant II Stent Graft According to Anatomic Severity Grade Score

OBJECTIVES

This study's objective was to evaluate Endurant II (Medtronic Inc, Minneapolis, Minnesota) stent graft's early and midterm outcomes and compare the results according to the anatomic severity grade (ASG) scores.

METHODS

This was a retrospective study of patients treated with the Endurant II stent graft between January 2013 and May 2021. The patients were divided into 2 independent groups, including those with a low ASG score (score <14) and a high ASG score (score >14).

RESULTS

A total of 165 consecutive patients (89% males, age 74±8 years) were included. There were 110 (67%) patients in the low-score group and 55 (33%) patients in the high-score group. Technical success was achieved in all cases. Primary clinical success at 30 days was 100% and at 1 year was 96%. Median operative time was longer in the high-score group with no statistical significance (133 vs 120 minutes, p=0.116). The median dose area product of low-score patients (50.9 Gy·cm2; IQR 22.4-75.5 Gy·cm2) was significantly lower than high-score patients (85.0 Gy·cm2; IQR 46.5-127.9 Gy·cm2) with p=0.025. Median fluoroscopic time was lower in low-score patients (17 minutes; IQR 13-24 minutes) compared with high-score patients (19 minutes; IQR 16-23 minutes) without a significant difference at p=0.148. At a midterm follow-up of 32 months (range 2-63 months), combined complications (29% vs 8%, p<0.001) and implant-related complications (13% vs 4%, p=0.043) were higher in the high-score group. Systemic complications at 30 days were higher in the high-score group without a statistically significant difference (15% vs 11%, p=0.500). The Kaplan-Meier estimate of freedom from reintervention was significantly higher in the low-risk group at 1 (97% vs 90%), 2 (96% vs 88%), and 3 years (96% vs 85%) with (p=0.035). The cumulative survival rate was significantly higher in the low-score group than high-score group (p=0.001) at 1 (99% vs 87%), 2 (98% vs 85%), and 3 years (96% vs 82%).

CONCLUSIONS

Endurant II endovascular aneurysm repair seems to be safe in both low-score and high-score patients. However, patients in the high-score group showed more implant-related complications and midterm mortalities than those in the low-score group.

Gender Differences in Aortic Anatomic Severity Grade and Long-Term Survival Following Elective Abdominal Aortic Aneurysm Repair at a Single Tertiary Center

BACKGROUND

Anatomic severity grade (ASG) score is utilized to assess preoperative abdominal aortic aneurysms (AAA) and provide a quantitative data on its anatomic complexity. The aim of this study is to determine the anatomical differences and long-term survival between male and female patients undergoing elective AAA repair.

METHODS

All patients undergoing intact AAA repair from 2007 to 2014 were included. ASG scores were calculated based on preoperative anatomical characteristics including aortic neck, aneurysm, and iliac artery. Standard univariate analysis was used to evaluate patient and anatomical characteristics. Kaplan-Meier survival curves were used to evaluate long-term survival at 1 and 5 years.

RESULTS

A total of 379 patients were identified, of which, majority of them were males (80%). Females were on average 3 years older (mean [SD]: 74.32 [8.63] vs. 71.92 [8.64] years) and were more likely to undergo open repair (29.7% vs. 17.5%) (both P < 0.05). Both groups had similar comorbidities. The mean long-term follow-up (S.D.) was 6.21 (3.81) years. No significant difference was seen between males versus females in long-term survival at both 1 year (86.3% vs. 92.8, P = 0.06) and 5 year (68.5% vs. 72.7%, P = 0.38). In regard to the anatomical characteristics, females had shorter aortic neck length (mean in mm [S.D.]: 17.67 [1.41] vs. 27.20 [15.76]), increased tortuosity index [mean (S.D.): 1.11 (0.07) vs. 1.09 (0.07)]) and higher calcification [mean % (S.D.): 17.12 (21.17) vs. 10.59 (16.82)] (All P < 0.05). In contrast, males had larger aortic neck (mean in mm (S.D.): 23.81 (4.17) vs. 22.41 (4.16)] and iliac artery [mean in mm (S.D.): 7.70 (1.91) vs. 6.28 (1.67)] diameter (both P < 0.05). The mean total ASG score was significantly higher among females versus males [mean (S.D.): 17.23 (4.01) vs. 15.67 (3.96), P = 0.003]. After stratifying by ASG score ≥15, females had significantly lower survival at 1 year compared to males (82.6% vs. 92.1%, P = 0.04). However, this difference disappeared at 5 years.

CONCLUSIONS

The data demonstrate that females present at an older age with more complex AAA anatomy than males. Based on anatomical complexities, females were more likely to undergo open repair, with a corresponding increase in 1-year mortality, but not at 5 year. The data suggest that care processes for optimization of aortic surgery in females are needed to improve 1-year survival.

Identifying high risk for proximal endograft failure after EVAR in patients suitable for both open and endovascular elective aneurysm repair

INTRODUCTION

Proximal endograft failure (type Ia endoleak or migration) after endovascular aneurysm repair (EVAR) is associated with hostile aneurysm neck morphology. Neck scoring systems were developed to predict proximal endograft failure but were studied in retrospective studies, which due to selection bias may have led to an overestimation of bad outcomes after EVAR. To predict patients who benefit from open repair, preoperative neck morphology and occurrence of long-term proximal endograft failure were investigated in patients enrolled in the endovascular arm of the DREAM-trial who were suitable for open repair by definition and have long-term follow-up.

METHODS

A post-hoc on-treatment analysis of patients after EVAR was performed in 171 patients. Aneurysm neck morphology was quantified using the aneurysm severity grading (ASG)-neck score calculated on pre-operative CT-angiography images. The ASG-neck score was used to predict proximal endograft failure. ROC analysis was performed to calculate a threshold to divide favorable and unfavorable aneurysm necks (low and high-risk), positive and negative likelihood-ratios were calculated accordingly. Freedom from proximal endograft failure was compared between groups using Kaplan Meier analysis.

RESULTS

During a median follow-up of 7.6 years, 20 patients suffered proximal endograft failure. ROC analysis showed an AUC 0.77 (95% CI 0.65-0.90; p<0.001) indicating acceptable prediction. The threshold was determined at ASG-neck score ≥5, 30 patients had unfavorable neck morphology of whom 11 developed proximal endograft failure. The positive likelihood-ratio was 4.4 (95% CI 2.5-7.8) and the negative likelihood-ratio was 0.51 (95% CI 0.3-0.8). Twelve years postoperatively, freedom from proximal endograft failure was 91.7% in favorable and 53.2% in unfavorable groups, difference 38.5% (95% CI 13.9-63.1; p<0.001).

CONCLUSION

In this study, the ASG-neck score predicted proximal endograft failure during the entire follow-up. This exhibits the persistent risk for proximal endograft failure long after EVAR and calls for ongoing surveillance especially in patients with unfavorable aneurysm necks.

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.

ERA OF ENDOVASCULAR AORTIC ANEURYSM REPAIR IS LINKED TO PREOPERATIVE ANATOMIC SEVERITY AND PERIOPERATIVE PATIENT OUTCOMES

OBJECTIVE

Varying opinions on optimal elective and emergent surgical management of infrarenal AAAs are expressed by the most recent Society for Vascular Surgery (SVS), European Society for Vascular Surgery (ESVS), versus NICE (National Institutes for Health and Care Excellence, UK) guidelines. The NICE guidelines propose that open surgical repair (OSR) serve as the default treatment for infrarenal AAA. The rationale for this approach relied on data from the early era of endovascular aneurysm repair (EVAR), and are in contrast to the more balanced approaches of the SVS and ESVS. We hypothesize that significant differences in patient selection, management, and postoperative outcome are related to the era in which treatment was undertaken, contextualizing the outcomes reported in early era EVAR RCTs.

METHODS

Retrospectively, two cohorts representing all EVAR patients from "early", n= 167 (2008-2010) and "late" n=129 (2015-2017) periods at a single treating institution, were assembled. Primary outcomes of era-related changes in preoperative demographics, anatomy, and intraoperative events were assessed; anatomy was compared using the Society for Vascular Surgery Anatomic Severity Grading (ASG) system. These era-related differences were then placed in the context of early perioperative outcomes and at follow-up to one year.

RESULTS

Choice of surgical strategy differed by era, despite the same patient preoperative comorbidities between EVAR groups. Preoperative anatomic severity was significantly worse in the early cohort (p<.001), with adverse proximal and distal seal zone features (p<·001). Technical success was 16·2% higher in the late cohort, with significantly fewer type 1A/B endoleaks perioperatively (p<.001). In-hospital complications, driven by higher acute kidney injury and surgical site complications in the early cohort, resulted in a 16·5% difference between cohorts (p<0·05). At one year of follow-up, outcome differences persisted; late era patients had fewer 1A endoleaks, fewer graft complications, and better reintervention-free survival.

CONCLUSIONS

From a granular dataset of EVAR patients, we found an impact of EVAR repair era on early clinical outcome; late cohort infrarenal (IR) EVAR patients had less severe preoperative anatomy, and improved perioperative and follow-up outcomes to one year, suggesting that the results of early EVAR RCTs may no longer be generalizable to modern practice.

Aortic Anatomic Severity Grade Correlates with Midterm Mortality in Patients Undergoing Abdominal Aortic Aneurysm Repair

BACKGROUND

Anatomic severity grade (ASG) can be used to assess abdominal aortic aneurysm (AAA) anatomic complexity. High ASG is associated with complications following endovascular repair of AAAs and we have demonstrated that ASG correlates with resource utilization. The hypothesis of this study is that ASG is directly related to midterm mortality in patients undergoing AAA repair.

METHODS

Patients who underwent infrarenal AAA repairs between July 2007 and August 2014 were retrospectively reviewed and ASG scores were calculated using 3-dimensional computed tomography reconstructions. Perioperative mortalities (≤30 days) were excluded. The ASG value of 15 was chosen based on previous receiver-operator curve analysis, which showed that an ASG of 15 was predictive of postoperative complications and resource utilization. The 5-year survivors and mortalities were compared utilizing comorbidities, pharmacologic variables, and anatomic variables at or above the defined threshold.

RESULTS

A total of 402 patients (80% male and 96% Caucasian) with complete anatomic and survival data were included in the analysis. Mean ASG and age at the time of repair were 16 ± 0.15 and 73 ± 0.43 years old, respectively. The 5-year mortality was significantly associated with ASG >15 (hazard ratio [HR]: 1.504, confidence interval [CI]: 1.077-2.100, P < .017), hyperlipidemia (HR: 1.987, CI: 1.341-2.946, P < .001), coronary artery disease (HR: 1.432, CI: 1.037-1.978, P < .029), and chronic obstructive pulmonary disease (HR: 1.412, CI: 1.027-1.943, P < .034). Kaplan-Meier analysis demonstrated improved survival in the low score ASG ≤15 group at 1, 3, and 5 years (96% vs 93%, 81% vs 69%, and 53% vs 41%; P = .0182; Figure 1).

CONCLUSIONS

Increasing aortic anatomic complexity as characterized by ASG >15 is an independent predictor of midterm mortality following elective infrarenal AAA repair. Therefore, it may be a useful tool for appropriate patient selection and risk stratification prior to elective infrarenal AAA repair.

What Did Endovascular Aortic Repair Bring for the Treatment Strategy of Abdominal Aortic Aneurysm?

Objective: We examined the effects of the introduction of endovascular aortic repair (EVAR) on treatment for abdominal aortic aneurysms (AAAs).

Subjects: We compared patients in the following three periods: period I (January 2002–December 2006, 105 patients), period II (January 2007–December 2011, 242 patients, duration of 5 years after the introduction of EVAR), and period III (January 2012–December 2016, 237 patients, duration of 5 years after period II). We used the American Society of Anesthesiologists (ASA) classification for risk assessment.

Results: In the Open repair (OR) group, the incidences of ASA class 2 increased and classes 3 and 4 decreased significantly in periods II and III compared with period I. In all periods, there were no in-hospital deaths. Suprarenal aortic cross-clamping was required in 18 patients (19.1%) in period III and 5 patients (6.3) in period I, and the difference was significant (P<0.05). In the EVAR group, no differences in age, sex, or ASA classification class were observed between periods II and III. In period II, one patient died due to aneurysm rupture during surgery. Significant differences were observed when comparing both groups in periods II and III: patients in the EVAR group were older (P<0.01) and the OR group had a higher proportion of ASA class 2 patients and the EVAR group had a higher proportion of ASA class 3 or 4 patients (P<0.01). Among all AAA surgeries, rupture occurred in 25 patients (23.8%) in period I, 18 patients (7.4) in period II, and 16 patients (6.8) in period III. The number of ruptures was significantly lower in periods II and III than in period I (P<0.01).

Conclusions: The findings of this study suggest that EVAR should be indicated for high-risk patients and had the good outcome of AAA treatment. (This is a translation of Jpn J Vasc Surg 2018; 27: 27–32.)

Customized endovascular repair of common iliac artery aneurysms

Open technique for elective repair of iliac artery aneurysms can be safely performed with good outcomes but not inconsequential morbidity. An endovascular approach has been shown to have both periprocedural and postoperative advantages with equivalent outcomes. Endovascular repair of common iliac arteries (CIAs) without sacrificing the hypogastric artery using an iliac branch device is a complex endovascular technique requiring a proximal seal zone that may be absent in larger CIA aneurysms. We present two cases in which CIA aneurysms were repaired with a customized endovascular technique using the benefit of the aortic bifurcation for stability in addition to providing a long proximal seal zone with the AFX device (Endologix, Irvine, Calif) paired with the iliac branch device (W. L. Gore & Associates, Flagstaff, Ariz) for internal iliac artery preservation.

Aortoiliac calcification correlates with 5-year survival after abdominal aortic aneurysm repair

BACKGROUND

An anatomic severity grade (ASG) score to categorize and to define anatomic factors for abdominal aortic aneurysm (AAA) repair was proposed. Other studies have previously reported that aortic anatomic complexity is a marker of survival and resource utilization after repair, although it remains unclear whether individual components of the ASG score independently contribute to survival. This study analyzed and validated an aortic and iliac artery calcium scoring system that can potentially predict survival after AAA repair.

METHODS

Patients who underwent infrarenal AAA repairs from July 2007 to May 2012 were analyzed using complete 5-year records. Those who died ≤30 days of surgery were excluded. Calcium score (CS) was defined using the ASG scoring system for its basis by preoperative imaging <6 months before surgery. A CS for any patient was 0 to 5 points, the sum of the points assigned to aortic neck (2 points total) and iliac artery (3 points total) calcification. A receiver operating characteristic curve was used to determine a CS threshold for mortality. The 5-year survivors and deaths were compared in regard to comorbidities, pharmacology, and CS at or above the defined threshold. Each variable with a P value <.1 between the groups was then placed into a Cox proportional hazards model, with statistical significance of P < .05.

RESULTS

There were 356 patients who underwent AAA repair with complete 5-year follow-up data; 26% died within 5 years of surgery. Of these, 13% had CS of 0 with 15% mortality, 28% had CS of 1 with 21% mortality, 24% had CS of 2 with 24% mortality, 23% had CS of 3 with 35% mortality, 10% had CS of 4 with 40% mortality, and 2% had CS of 5 with 17% mortality. The receiver operating characteristic curve demonstrated an appropriate threshold of CS 3. Of these patients, 65% had a CS <3, whereas 35% had a CS ≥3. Patients with a CS ≥3 had a lower 5-year survival probability (P = .003). Comparing 5-year survivors and deaths in a Cox proportional hazards analysis, CS ≥3 was associated with a hazard ratio of 1.579 (95% confidence interval, 1.038-2.402; P = .0328).

CONCLUSIONS

A CS ≥3 is linked to a lower 5-year survival after AAA repair in our population. This system potentially can be another measure for risk stratification and serve as a means to predict midterm mortality in AAA repairs. Future study will be needed for further validation to predict midterm mortality and to better guide surgical decision-making.

Systematic review of mortality risk prediction models in the era of endovascular abdominal aortic aneurysm surgery

BACKGROUND

The introduction of endovascular aneurysm repair (EVAR) has reduced perioperative mortality after abdominal aortic aneurysm (AAA) surgery. The objective of this systematic review was to assess existing mortality risk prediction models, and identify which are most useful for patients undergoing AAA repair by either EVAR or open surgical repair.

METHODS

A systematic search of the literature was conducted for perioperative mortality risk prediction models for patients with AAA published since 2006. PRISMA guidelines were used; quality was appraised, and data were extracted and interpreted following the CHARMS guidelines.

RESULTS

Some 3903 studies were identified, of which 27 were selected. A total of 13 risk prediction models have been developed and directly validated. Most models were based on a UK or US population. The best performing models regarding both applicability and discrimination were the perioperative British Aneurysm Repair score (C-statistic 0·83) and the preoperative Vascular Biochemistry and Haematology Outcome Model (C-statistic 0·85), but both lacked substantial external validation.

CONCLUSION

Mortality risk prediction in AAA surgery has been modelled extensively, but many of these models are weak methodologically and have highly variable performance across different populations. New models are unlikely to be helpful; instead case-mix correction should be modelled and adapted to the population of interest using the relevant mortality predictors.