The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm

Saccular and Fusiform Abdominal Aortic Aneurysms Treated With Endovascular Repair Differ in Presentation and Treatment Threshold: Analyses Using a National Clinical Database in Japan

BACKGROUND

Saccular abdominal aortic aneurysms (AAAs) are considered to be at higher risk of rupture than fusiform AAAs, but not much is known about the extent of this risk. Therefore, this study aimed to compare the rupture presentation between fusiform and saccular AAAs.

METHODS AND RESULTS

This is a retrospective cohort study on 27 290 patients who underwent primary endovascular repair for a degenerative AAA between 2016 and 2019, and who were registered in the National Clinical Database in Japan. At operation for nonruptured case, the aneurysm diameter was significantly smaller in saccular AAAs than in fusiform AAAs (median, 44.0 versus 51.0 mm; P<0.001). Similarly, aneurysm diameter at rupture was significantly smaller in saccular AAAs than in fusiform AAAs (median, 55.6 versus 68.0 mm; P<0.001). The likelihood of repair for rupture was significantly higher in saccular AAAs than in fusiform AAAs in the 40- to 54-mm diameter range, in which saccular morphology was found to be an independent risk factor for rupture against fusiform morphology by adjusting for sex and aneurysm diameter (odds ratio, 2.54 [95% CI, 1.75-3.69]). In addition, receiver-operating characteristic curve analysis revealed that the cutoff diameter to predict rupture was smaller in saccular AAAs than in fusiform AAAs (50.5 and 59.5 mm, respectively) based on the Youden index.

CONCLUSIONS

Saccular AAAs presented at smaller diameters than fusiform AAAs in patients with ruptured AAAs treated with endovascular aortic repair, which supports the idea that saccular AAAs should be treated at smaller diameters.

A Patient-Centered Textbook Outcome Measure Effectively Discriminates Contemporary Elective Open Abdominal Aortic Aneurysm Repair Quality

INTRODUCTION

There is persistent controversy surrounding the merit of surgical volume benchmarks being used solely as a sufficient proxy for assessing the quality of open abdominal aortic aneurysm (AAA) repair. Importantly, operative volume quotas may fail to reflect a more nuanced and comprehensive depiction of surgical outcomes most relevant to patients. Accordingly, we herein propose a patient-centered "textbook outcome" (TO) for AAA repair that is analogous to other large magnitude extirpative operations performed in other surgical specialties, and test its feasibility to discriminate hospital performance using Society for Vascular Surgery (SVS) volume guidelines.

METHODS

All elective open infrarenal AAA repairs (OAR) in the SVS-Vascular Quality Initiative were examined (2009-2022). The primary end-point was a TO, defined as a composite of no in-hospital complication or re-intervention/re-operation, length of stay ≤ 10-days, home discharge and 1-year survival. The discriminatory ability of the TO measure was assessed by comparing centers that did or did not meet the SVS annual OAR volume threshold recommendation (high-volume ≥ 10 OARs/year; low-volume <10 OARs/year). Logistic regression and multivariable models adjusted for patient and procedure-related differences.

RESULTS

A total of 9,657 OARs across 198 centers were analyzed (mean age-69.5±8.4, female-26%, non-white-12%). A TO was identified in 44% (N = 4,293) of the overall cohort. The incidence of individual TO components included: no in-hospital complication (61%), no in-hospital re-intervention/re-operation (92%), LOS ≤ 10-days (78%), home discharge (76%), and 1-year survival (91%). Median annual center volume was 6 [IQR 3, 10] and a majority of centers did not meet the SVS volume suggested threshold (<10 OARs/year: N = 148 [74%]). However, most patients (N = 6,265 of 9,657 [65%]) underwent OAR in high-volume hospitals. When comparing high and low-volume centers, a TO was more likely to occur in high-volume institutions: ≥10 OARs/year, 46% vs. <10 OARs/year, 42%; P=.0006. The association of a protective effect for higher center volume remained after risk adjustment: OR 1.1, 95%CI 1.05-1.26; P=.003.

CONCLUSIONS

Textbook outcomes for elective OAR reflect a more nuanced and comprehensive patient centered proxy to measure care delivery consistent with other surgical specialties. Surprisingly, a TO was achieved in < 50% of elective AAA cases nationally. Though the likelihood of a TO appears to correlate with SVS center volume recommendations, it more importantly reflects elements which may be prioritized by patients and thus offers insights into further improving real-world AAA care.

Acute kidney injury in patients undergoing endovascular or open repair of juxtarenal or pararenal aortic aneurysms

BACKGROUND

The aim of this cohort study was to report the proportion of patients who develop periprocedural acute kidney injury (AKI) after endovascular repair (ER) and open surgery (OS) in patients with juxta/pararenal abdominal aortic aneurysm and to assess potential risk factors for AKI. The study also aimed to report the short- and long-term outcomes of patients with and without AKI.

METHODS

This was a multicenter cohort study of five European academic high-volume centers (>50 OS or 50 ER infrarenal AAA repairs, plus >15 complex AAA repairs per year). All consecutively treated patients were extracted from a prospective vascular surgical registry and the data were scrutinized retrospectively. The primary end point for this study was the development of AKI. AKI was diagnosed when there is a two-fold increase of serum creatinine or decrease of glomerular filtration rate of >50% within 1 week of AAA repair. Secondary end points included long-term mortality and end-stage renal disease (ESRD).

RESULTS

AKI occurred in 16.6% of patients in the ER group vs 30.3% in the OS group (P < .001). The 30-day mortality rate was higher among patients with AKI in both ER (15.4% vs 3.1%; P = .006) and OS (13.2% vs 5.3%; P = .001) groups. Age, chronic kidney disease, presence of significant thrombus burden in the pararenal region, >1000 mL blood loss in ER group were associated with development of AKI. Age, diabetes mellitus, chronic kidney disease, presence of significant thrombus burden in the pararenal region, and a proximal clamping time of >30 minutes in the OS group were associated with the development of AKI, whereas renal perfusion during clamping was the protective factor against AKI development. After a median follow-up of 91 months, AKI was associated with higher mortality rates in both the ER group (58.9% vs 29.7%; P < .001) and the OS group (61.5% vs 27.3%; P < .001). After the same follow-up period, AKI was associated with a higher incidence of ESRD in both the ER group (12.8% vs 3.6%; P = .009) and the OS group (9.9% vs 2.9%; P < .001).

CONCLUSIONS

The current study identified important pre and postoperative factors associated with AKI after juxta/pararenal abdominal aortic aneurysm repair. Patients with postoperative AKI had significantly higher short- and long term mortality and higher incidence of ESRD than patients without AKI.

Simultaneous hybrid repair of symptomatic femoral, iliac, and abdominal aortic aneurysms

BACKGROUND

Focal peripheral arterial aneurysms, though rare, have a relatively high association with coexisting synchronous or metachronous aneurysms. While most are asymptomatic at presentation, there is concern for aneurysm thrombosis, embolization, or rupture, which can lead to acute limb ischemia or even limb loss. These complications require early intervention with either open or endovascular surgery, oftentimes staged due to complexity.

METHOD

We describe a case of a 65-year-old male presenting with a symptomatic common femoral artery aneurysm with a simultaneous infrarenal abdominal aortic aneurysm, requiring a hybrid endovascular and open approach for operative repair due to the size and characteristics of his aneurysms.

DISCUSSION

As the consensus for the management of synchronous/metachronous aneurysms is to stage the procedures, it is important to report scenarios where a single hybrid operation was technically feasible and resulted in good patient outcomes.

CONCLUSION

This report supports the role of utilizing multiple hybrid operative techniques to best repair the respective aneurysm in a single operation, with favorable patient outcomes.

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 (D max ), 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%). D max ( β = 0.087) and MR strain ( β = -1.563) were both associated with AAA growth rate. The MR strain remained an independent factor associated with growth rate ( β = -0.904) after controlling for D max .

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.

Standardized approach for four-fenestrated physician-modified endograft to treat complex abdominal aortic aneurysms using Valiant Captivia

We describe the feasibility and safety of a standardized approach for four-fenestrated physician-modified endograft (PMEG) placement to treat complex abdominal aortic aneurysms using the Valiant Captivia platform (Medtronic). The standardization is based on specific selection criteria for anatomical feasibility, measurement method, and modification technique of a single endograft type. Six cases (two juxtarenal, two pararenal, and two type IV thoracoabdominal aneurysms) were treated, with 24 target vessels incorporated with fenestrations. Four cases were treated in an urgent setting and two were elective. The time modification required was 121 ± 18 minutes. Technical success was 100%, with no mortality or complications at 30 days. Postoperative computed tomography at 3 months demonstrated complete aneurysm exclusion, without a type I or III endoleak, no main graft- or fenestration-related loss of integrity, and no target vessel misalignment or stent fracture. The present standardized approach seems safe and feasible and might represent an initial benchmark for comparison with future studies.

ACR Appropriateness Criteria® Screening for Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a significant vascular disease found in 4% to 8% of the screening population. If ruptured, its mortality rate is between 75% and 90%, and it accounts for up to 5% of sudden deaths in the United States. Therefore, screening of AAA while asymptomatic has been a crucial portion of preventive health care worldwide. Ultrasound of the abdominal aorta is the primary imaging modality for screening of AAA recommended for asymptomatic adults regardless of their family history or smoking history. Alternatively, duplex ultrasound and CT abdomen and pelvis without contrast may be appropriate for screening. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Clinical outcomes for patients with cardiovascular diseases before, during, and after the COVID19 pandemic. A pooled analysis of 600.000 patients

BACKGROUND

The unexpected virulence of the COVID19 pandemic brought to significant changes of generally accepted therapeutic approaches. The consequences of these changes were difficult to define during the pandemic period.

METHODS

We analyzed the National Registries including 97% of hospital admissions in Italy, regarding data describing number of operations for aortic valve implantation or repair, carotid and coronary revascularization, AAA repair, and lower limb arterial reconstruction performed in the period 2015 to 2019 and in the pandemic years 2020, 2021, and 2022. Primary outcomes were number and type of surgical procedures, 30-days operative mortality.

RESULTS

During the three years of the pandemic there was a statistically significant increase of the number of all-causes deaths in comparison with the mean of the previous five years (2015-2019). In Italy there was a total increase of all causes-deaths of 251.911 (+105900 in 2020; +66929 in 2021; and +79082 in 2022), and 73% of the excess of deaths was related with COVID19 infection and 27% occurred in COVID 19 negative patients. During the first year of the pandemic, worse clinical outcomes for hospitalized patients with CVD were registered. The medical system responded adequately and in the following two pandemic years clinical outcomes for hospitalized patients were similar with those of the pre-pandemic period.

CONCLUSIONS

The unexpected virulence of COVID19 pandemic determined worse clinical outcomes for patients with CVD during the first year. The adopted preventive measures allowed in the following two pandemic years improved clinical outcomes, similar with those of the pre-pandemic period.

Pentamethylquercetin attenuates angiotensin II-induced abdominal aortic aneurysm formation by blocking nuclear translocation of C/EBPβ at Lys253

BACKGROUND

Pentamethylquercetin (PMQ) is a natural polymethyl flavonoid that possesses anti-apoptotic and other biological properties. Abdominal aortic aneurysm (AAA), a fatal vascular disease with a high risk of rupture, is associated with phenotypic switching and apoptosis of medial vascular smooth muscle cells (VSMCs). This study aimed to investigate the protective effects of PMQ on the development of AAA and the underlying mechanism.

METHODS

ApoE-/- mice were continuously infused with angiotensin II (Ang II) for 4 weeks to develop the AAA model. Intragastric administration of PMQ was initiated 5 days before Ang II infusion and continued for 4 weeks. In vitro, VSMCs were cultured and pretreated with PMQ, stimulated with Ang II. Real-time PCR, western blotting, and immunofluorescence staining were used to examine the roles and mechanisms of PMQ on the phenotypic switching and apoptosis of VSMCs.

RESULTS

PMQ dose-dependently reduced the incidence of Ang II-induced AAA, aneurysm diameter enlargement, elastin degradation, VSMCs phenotypic switching and apoptosis. Furthermore, PMQ also inhibited phenotypic switching and apoptosis in Ang II-stimulated VSMCs. PMQ exerted protective effects by regulating the C/EBPβ/PTEN/AKT/GSK-3β axis. AAV-mediated overexpression of PTEN reduced the therapeutic effects of PMQ in the AAA model mice, suggesting that the effects of PMQ on Ang II-mediated AAA formation were related to the PTEN/AKT/GSK-3β axis. PMQ inhibited VSMCs phenotypic switching and apoptosis by bounding to C/EBPβ at Lys253 with hydrogen bond to regulate C/EBPβ nuclear translocation and PTEN/AKT/GSK-3β axis, thereby inhibiting Ang II-induced AAA formation.

CONCLUSIONS

Pentamethylquercetin inhibits angiotensin II-induced abdominal aortic aneurysm formation by bounding to C/EBPβ at Lys253. Therefore, PMQ prevents the formation of AAA and reduces the incidence of AAA.

Direct sac puncture versus transarterial embolization of type II endoleaks after endovascular abdominal aortic aneurysm repair: Comparison of outcomes

PURPOSE

Type 2 endoleak (T2EL) is the most common type of endoleak after endovascular abdominal aortic aneurysm repair (EVAR), and increases the risk of aneurysm sac rupture if it persists beyond 6 months. The purpose of this study is to compare the efficacy and safety of direct sac puncture versus transarterial embolization of T2ELs.

METHODS

Retrospective review of 42 consecutive T2EL embolization procedures, 19 by DSP and 23 by transarterial technique, between January 2015 and December 2020. Primary outcome was aneurysm sac stability and resolution of endoleak at follow-up imaging. Adverse events (AE) were classified based on the Society of Interventional Radiology (SIR) practice guidelines.

RESULTS

Technical success was 94.7% (18/19) in the DSP group and 86.9% (20/23) in the transarterial group (p = 0.32 (-0.77-0.25)). Treatment efficacy was evaluated in 16 patients in the DSP group and 18 patients in the transarterial group who had follow-up imaging ≥6 months after embolization. Mean imaging follow-up was 17.1 ± 11.2 (range, 6-41) months in the DSP group and 26.5 ± 15.4 (range, 6-48) months in the transarterial group (p = 0.06, -19.24-0.37). Treatment efficacy was 75% (12/16) in the DSP group and 33.3% (6/18) in the transarterial group (p = 0.02, 95% CI, 0.09-0.97). There was no procedure-related mortality. Moderate-severe AE occurred in 15.7% (3/19) in the DSP group and 8.7% (2/23) in the transarterial group (p = 0.44, -0.12-0.26).

CONCLUSION

In this study, DSP embolization of T2EL was equally safe and more effective than transarterial embolization in achieving aneurysm sac stability and resolution of endoleak.

A systematic review and case presentation: Giant abdominal aortic aneurysm

OBJECTIVE

An abdominal aortic aneurysm is considered giant when its transverse diameter is greater than 10-13 cm in diameter. A giant abdominal aortic aneurysm is rare but with a significant risk of rupture if it is not diagnosed or left untreated.

METHOD

The authors have performed a systematic review of the evidence that has looked into the clinical presentations, and management methods employed and have presented a 14 cm giant abdominal aortic aneurysm patient.

RESULTS

The systematic review has been based on level-IV evidence due to the rarity of the condition. The final analysis included 61 relevant reported cases. The mean age was 72.4 years, the male to female ratio was 52: 8, and the average size of a giant abdominal aortic aneurysm was 14.7 cm. These were mostly infra renal (72.58%). Rupture of these aneurysms was found in 23 (37.1%) patients, and was treated by laparotomy in 51 (82.25%) cases. There were 11 (17.74%) mortalities.

CONCLUSION

The size of an abdominal aortic aneurysm is known to be the biggest factor in the rupture of an aneurysm. The reason abdominal aortic aneurysms can reach such size without rupturing is unclear but needs further exploring. Early diagnosis with effective screening programmes is essential to diagnose in a timely manner to avoid life-threatening consequences.

Initial Experience of the Covered Endovascular Reconstruction of Iliac Bifurcation Technique

INTRODUCTION

The distal landing zone in iliac arteries represents an important issue during endovascular repair of abdominal aortic aneurysms (EVAR). The aim of this study is to present a case series for landing in the external iliac artery (EIA) during EVAR while preserving blood flow in the internal iliac artery (IIA) with the covered endovascular reconstruction of the iliac bifurcation (CERIB) technique.

METHODS

This is a single-center, retrospective analysis of prospectively collected data of patients that underwent EVAR either for intact abdominal aortic aneurysm (AAA) or previous failed EVAR from December 2022 up to September 2023. Indications for treatment were presence of common iliac artery aneurysm (CIAA), short CIA, or endoleak type Ib (ETIb). For the distal sealing zone, we used balloon-expandable covered stent (BXCS). Primary outcomes were technical success and first-month patency rate. Secondary outcomes were endoleak and re-intervention rate.

RESULTS

Sixteen patients being treated with 20 CERIBs were included in the study. Four patients had a previous failed EVAR, while 3 patients were treated urgently for a symptomatic para-renal aneurysm. The indications for treatment were EIb (n=2), short CIA (n=4), CIAA with narrow lumen (n=3), and CIA aneurysm (n=11). Platforms that were used were the Cook Zenith Alpha (n=5), Gore C3 (n=2 and 3 limbs), Endurant IIs (n=2, and 3 limbs), and a t-branch device (n=3). Technical success rate was 100% with no adjunctive procedure. No death or re-intervention was recorded for all patients at postoperative 30-day period and at 6 months for 2 patients. At first-month CTA, patency rate was 100% (20/20), while in 2 patients that had 6-month CTA, the patency was also 100% (2/2). No kinking or stenosis was also noted. Two patients had ETIII after branched EVAR (BEVAR), 2 patients had ETII, and 1 patient had gutter ET in the area of the CERIB.

CONCLUSION

The CERIB technique seems to be effective and safe in the early period. It is suitable with a variety of commercial endograft platforms. It may be a valuable alternative to iliac branch devices when there are anatomical considerations. Longer follow-up is needed to conclude for long-term patency and durability.

CLINICAL IMPACT

The distal landing zone in iliac arteries represents an important issue during EVAR while it is important to preserve blood flow in the internal iliac artery. The covered endovascular reconstruction of the iliac bifurcation (CERIB) technique is a technique for the preservation of internal iliac arteries during EVAR, while it is suitable with a variety of commercial endograft platforms. The CERIB technique seems to be effective and safe in the early period. It may be valuable alternative to iliac branch devices when there are anatomical considerations.

Multicentric Use of Commercially Available Infrarenal Endografts During Fenestrated Endovascular Aortic Repair: A Feasibility Study

PURPOSE

This study aimed to assess the feasibility and short-term outcomes of different manufactured proximal and distal stent graft components during fenestrated endovascular aortic repair (FEVAR).

MATERIALS AND METHODS

A multicenter retrospective review was conducted at 3 aortic centers, involving all consecutive patients who underwent FEVAR utilizing a customized Dacron-based tubular proximal and a distal bifurcated polytetrafluoreten (PTFE)-based commercially available stent grafts. Primary outcomes were 30 day mortality, major adverse events, and technical and clinical success. Secondary outcomes assessed stent graft migration, occurrence of types I/III endoleak, and reintervention.

RESULTS

A total of 23 FEVAR cases across all centers were included in this study. Technical success was achieved in all cases, with a median procedure time of 183 (153-244) minutes. There were no major adverse events, except for 1 transient acute renal failure. The median follow-up period was 23 (17-28) months. All target vessels retained patent with the exception of 1 right renal fenestration that showed signs of kinking at the first follow-up, and despite secondary intervention with relining and distal extension, there was an occlusion afterward and 1 hepatic artery with a separate fenestration. This and 1 successful relining of a superior mesenteric artery kink were the only reinterventions in this cohort. One case of persistent type 1b endoleak was reported in a patient with chronic type B aortic dissection, which resolved with distal extension on the external iliac artery 5 months after the index procedure. No deaths occurred throughout the follow-up with, and there were no signs of stent graft migration or type 3 endoleak.

CONCLUSION

The use of commercially available PTFE-based bifurcated stent grafts to extend distally the tubular graft appears to be a feasible approach during FEVAR, with promising short-term outcomes. Further studies are necessary to define the applicability of this solution and evaluate long-term outcomes.

CLINICAL IMPACT

This multicentric study on fenestrated endovascular aortic repair (FEVAR) demonstrates the feasibility and good short-term outcomes of utilizing a PTFE-based commercially available stent graft to extend the proximal tubular custom-made fenestrated stent graft. The high technical success rate, absence of major adverse events, and low occurrence of complications such as stent graft migration and endoleaks highlight the potential clinical benefits of this approach with an off-the-shelf distal extension whose delivery system does not cross the fenestrations intraoperatively.

The role of narrow aortic bifurcation in affecting EVAR treatment and outcomes

OBJECTIVES

The narrow aortic bifurcation is considered a risk factor for endograft thrombosis after aorto-biiliac endovascular aortic repair (EVAR) for aortic or iliac aneurysm. Nowadays, no consensus on the threshold diameter for the definition of narrow aortic bifurcation is reached and other aortic bifurcation features are rarely considered. The aim of the study is to assess the EVAR outcomes using bifurcated endograft according to anatomical characteristics of aortic bifurcation.

METHODS

The study included patients treated with primary EVAR from 2016 to 2022. A retrospective analysis of single-center prospectively collected database was performed. Patients were classified in standard aortic bifurcation (SAB; aortic bifurcation diameter >20mm), narrow aortic bifurcation (NAB; ≤20mm and >16mm) and extremely narrow aortic bifurcation (eNAB; ≤16mm). The three groups were compared in terms of patient demographics, risk factors, procedure setting (elective or urgent/emergent), type of deployed endograft. In NAB and eNAB groups, severe calcification (SC) and length of stenotic aortic bifurcation >10mm (long-NAB) were assessed from pre-operative imaging. In SAB, NAB and eNAB groups, following outcomes were evaluated: rate of intraoperative iliac endograft stenting (unilateral or kissing stenting), primary patency (PP), freedom from endograft-related reintervention (ffER) and overall survival during follow-up.

RESULTS

The total number of deployed aorto-biiliac endografts was 365 (mean age: 76.6 years ±7.4; male 89.3%): SAB 298 (81.6%), NAB 57 (15.6%) and eNAB 10 (2.7%) cases. Female gender, COPD and active smokers were more frequent in patients with smaller aortic bifurcation diameter (p=.002, .039 and .010, respectively). In NAB and eNAB groups, SC was reported in 18/67 cases (26.9%) and long-NAB in 15/67 cases (25.4%). Patients with eNAB have more frequent SC of aortic bifurcation (60% vs NAB 21.1%, p=.018) and long-NAB (50% vs NAB 17.5%, p=.023). In SAB, sNAB and eNAB, intraoperative iliac endograft stenting was performed in 34/298 (11.4%), 9/57 (15.8%) and 5/10 (50%), respectively (p=.001). Kissing stenting was performed more frequently in groups with smaller aortic bifurcation diameter (p=.010). Mean follow-up was 30.2 months ±21.5. At 1, 3 and 5 years, PP was 98.5%, 96.6% and 95.6%, respectively. eNAB had lower rate of PP compared to NAB group (p=.030). Long-NAB had lower rate of PP (p=.035). At 1, 3 and 5 years, ffER was 96.8%, 86.7% and 76.7%, respectively, with no differences between three groups (p=.423). At 1, 3 and 5 years, survival was 92.5%, 77.6% and 58.1%, respectively, with no difference between SAB, sNAB and eNAB (p=. 673).

CONCLUSIONS

Female, COPD patients and active smokers have more frequently smaller aortic bifurcation diameter. eNAB patients have more challenging anatomical characteristics compared with NAB group, requiring higher rate of intraoperative stenting, especially kissing stenting. Mid-term PP seems to be negatively influenced by aortic bifurcation ≤16mm and long-NAB.

Incidence, Predictors, and Implications of Secondary Aortic Intervention Following Thoracic Endovascular Aortic Repair for Type B Dissection

BACKGROUND

Secondary aortic intervention (SAI) following thoracic endovascular aortic repair (TEVAR) is not uncommon. However, a satisfactory management system has not been established for these patients. We aimed to report our single-center experience with SAI after prior TEVAR for type B aortic dissection (TBAD).

METHODS

From January 2010 to May 2017, 860 eligible patients with TBAD underwent TEVAR. One hundred seven (12.4%) patients required SAI, either endovascularly (n=76) or surgically (n=31). The main indications for SAI were entry flow (n=58 [54.2%]), aneurysm expansion of the proximal or remote aorta (n=26 [24.3%]), retrograde type A aortic dissection (n=11 [10.3%]), distal stent-graft-induced new entry tear (n=6 [5.6%]), and stent migration (n=4 [3.7%]). The Kaplan-Meier curves were generated to determine the degree of freedom from SAI and the prognosis. Cox proportional hazards were used to screen for risk factors for SAI and poor prognosis.

RESULTS

The overall 30-day mortality rate after SAI was 4.7% (n=5): endovascular (n=2 [2.6%]) vs open surgery (n=3 [9.7%]; p=0.145). The cumulative survival rates with or without SAI were 86.3%±3.6% vs 95.7%±0.8% at 3 years and 82.0%±4.2% vs 92.2%±1.1% at 5 years, respectively (log-rank p<0.001). Although no significant difference in survival was observed, the incidence of SAI was significantly greater in patients who underwent TEVAR during the chronic phase (acute [11.6%] vs subacute [9.6%] vs chronic [27.8]; p<0.001). Multivariate regression analysis revealed that prior TEVAR in the chronic phase (hazard ratio [HR]=1.73, 95% confidence interval [CI]=1.03-2.90; p=0.039), maximum aortic diameter (HR=1.05, 95% CI=1.04-1.07; p<0.001), and arch involvement (HR=1.48, 95% CI=1.01-2.18; p=0.048) were predictors of the incidence of SAI. In addition, the maximum aortic diameter was demonstrated to be the only risk factor for prognosis after adjusting for confounding factors.

CONCLUSIONS

Thoracic endovascular aortic repair for chronic TBAD patients should be reconsidered. Open surgery is preferable for those with proximal progression, whereas endovascular treatment is more suitable for distal lesions. Close surveillance and timely reintervention after TEVAR, whether via endovascular techniques or open surgery, are necessary to prevent devastating complications.

CLINICAL IMPACT

The management of patients with type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR) is challenging. We summarized our single-center experience regarding secondary aortic intervention after TEVAR for TBAD. We found that TEVAR for chronic TBAD patients should be carefully evaulated, and open surgery is recommended for those with proximal progession, while endovascular treatment is more preferable for distal lesions.

Retrospective analysis of 1,203 cases of referral to a quaternary vascular surgery outpatient clinic within the Unified Health System, São Paulo, Brazil

OBJECTIVE

Through a retrospective analysis of 1,203 cases of referral from primary healthcare units to a specialized quaternary vascular surgical service, the findings of this study revealed a high proportion of inappropriate referrals, which may represent a substantial subutilization of this highly complex service. Consequently, in this study, we aimed to evaluate 1,203 cases of referral to a quaternary vascular surgical service, in São Paulo, Brazil, over a 6-year period, to assess the appropriate need for referral; in addition to the prevalence of surgical indications.

METHODS

In this retrospective analysis, we reviewed the institutional records of participants referred from Basic Healthcare Units to a vascular surgical service inside the Brazilian Unified Health System, between May 2015 and December 2020. Demographic and clinical data were collected. The participants were stratified, as per the reason for referral to the vascular surgical service, previous imaging studies, and surgical treatment indications. Referral appropriateness and complementary examinations were evaluated for each disease cohort. Finally, the prevalence of cases requiring surgical treatment was defined as the outcome measure.

RESULTS

Of the 1,203 referrals evaluated, venous disease was the main reason for referral (53%), followed by peripheral arterial disease (19.4%). A considerable proportion of participants had been referred without complementary imaging or after a long duration of undergoing an examination. Referrals were regarded as inappropriate in 517 (43%) cases. Of these, 32 cases (6.2%) had been referred to the vascular surgical service, as the incorrect specialty. The percentage of referred participants who ultimately underwent surgical treatment was 39.92%. Carotid (18%) and peripheral arterial diseases (18.4%) were correlated with a lower prevalence of surgical treatments.

CONCLUSION

The rate of referral appropriateness to specialized vascular care from primary care settings was low. This may represent a subutilization of quaternary surgical services, with low rates of surgical treatment.

Mechanism and clinical implication of gut dysbiosis in degenerative abdominal aortic aneurysm: A systematic review

The gut microbiome is the entirety of microorganisms and their genomes residing in the gut, characterised by diversity, stability, and resilience. Disrupted gut microbiome has been implicated in multiple disease entities. The aim of this paper is to summarise the rapidly evolving contemporary evidence of gut dysbiosis on the development and progression of abdominal aortic aneurysm (AAA), discuss possible mechanisms, and explore potential microbiota-targeted interventions and prognostic markers for AAA. A systematic literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, using PubMed, ScienceDirect, Web of Science, Ovid, Embase. Search terms of "microbiome" OR "dysbiosis" OR "microorganism"; AND "aneurysm" OR "dilatation" OR "aorta" were used. Study endpoints included effects of microbiota on AAA formation, effects of specific type of bacteria and its metabolite on AAA formation, and pre- or post-treatment by novel small-molecules/inhibitors. From May to August 2023, a total of twelve animal studies and eight human studies were included. Akkermansia muciniphila, Lactobacillus acidophilus and species from the Bacteroidetes phylum were associated with lower AAA incidence in both animal and human studies, while Proteobacteria phylum, Campylobacter, Fusobacterium and Faecalibacterium prausnitzii were found to be in abundance in the AAA group and were associated with larger aneurysms. The diversity of gut microbiota was inversely correlated with AAA diameter. Three important mechanisms were identified: including trimethylamine N-oxide pathway, butyric acid pathway, and aberrant tryptophan metabolism. With our expanding knowledge of the downstream pathogenic mechanisms of gut dysbiosis, novel therapeutics such as short-chain fatty acids and spermidine, as well as prognostic biomarkers such as TMAO have yielded promising preclinical results. In conclusion, there is strong evidence corroborating the role of gut dysbiosis in the pathogenesis of AAA, wherein its therapeutic and prognostic potential deserves further exploration.

The Utility of Three-Dimensional Printing in Physician-Modified Stent Grafts for Aortic Lesions Repair

Background: Three-dimensional (3D) printing is becoming increasingly popular around the world not only in engineering but also in the medical industry. This trend is visible, especially in aortic modeling for both training and treatment purposes. As a result of advancements in 3D technology, patients can be offered personalized treatment of aortic lesions via physician-modified stent grafts (PMSG), which can be tailored to the specific vascular conditions of the patient. The objective of this systematic review was to investigate the utility of 3D printing in PMSG in aortic lesion repair by examining procedure time and complications. Methods: The systematic review has been performed using the PRISMA 2020 Checklist and PRISMA 2020 flow diagram and following the Cochrane Handbook. The systematic review has been registered in the International Prospective Register of Systematic Reviews: CRD42024526950. Results: Five studies with a total number of 172 patients were included in the final review. The mean operation time was 249.95± 70.03 min, and the mean modification time was 65.38 ± 10.59 min. The analysis of the results indicated I2 of 99% and 100% indicating high heterogeneity among studies. The bias assessment indicated the moderate quality of the included research. Conclusions: The noticeable variance in the reviewed studies' results marks the need for larger randomized trials as clinical results of 3D printing in PMSG have great potential for patients with aortic lesions in both elective and urgent procedures.

Dynamic Radial MR Imaging for Endoleak Surveillance after Endovascular Repair of Abdominal Aortic Aneurysms with Inconclusive CT Angiography: A Prospective Study

Background/Objectives: To assess free-breathing, dynamic radial magnetic resonance angiography (MRA) for detecting endoleaks post-endovascular aortic repair (EVAR) in cases with inconclusive computed tomography angiography (CTA). Methods: This prospective single-center study included 17 participants (mean age, 70 ± 9 years; 13 males) who underwent dynamic radial MRI (Golden-angle RAdial Sparse Parallel-Volumetric Interpolated BrEath-hold, GRASP-VIBE) after inconclusive multiphasic CT for the presence of endoleaks during the follow-up of EVAR-treated abdominal aortic aneurysms. CT and MRI datasets were independently assessed by two radiologists for image quality, diagnostic confidence, and the presence/type of endoleak. Statistical analyses included interrater and intermethod agreement, and diagnostic performance (sensitivity, specificity, area under the curve (AUC)). Results: Subjective image analysis demonstrated good image quality and interrater agreement (k ≥ 0.6) for both modalities, while diagnostic confidence was significantly higher in MRA (p = 0.03). There was significantly improved accuracy for detecting type II endoleaks on MRA (AUC 0.97 [95% CI: 0.87, 1.0]) compared to CTA (AUC 0.66 [95% CI: 0.41, 0.91]; p = 0.03). Although MRA demonstrated higher values for sensitivity, specificity, AUC, and interrater agreement, none of the other types nor the overall detection rate for endoleaks showed differences in the diagnostic performance over CT (p ≥ 0.12). CTA and MRA revealed slight to moderate intermethod concordance in endoleak detection (k = 0.3-0.64). Conclusions: The GRASP-VIBE MRA characterized by high spatial and temporal resolution demonstrates clinical feasibility with good image quality and superior diagnostic confidence. It notably enhances diagnostic performance in detecting and classifying endoleaks, particularly type II, compared to traditional multiphase CTA with inconclusive findings.

Polyvascular Disease: A Narrative Review of Risk Factors, Clinical Outcomes and Treatment

PURPOSE OF REVIEW

Polyvascular disease has a significant global burden and is associated with increased risk of major adverse cardiac events with each additional vascular territory involved. The purpose of this review is to highlight the risk factors, associated outcomes, emerging genetic markers, and evidence for screening and treatment of polyvascular disease.

RECENT FINDINGS

Polyvascular disease is the presence of atherosclerosis in two or more vascular beds. It has a significant global burden, with a prevalence of 30-70% in patients with known atherosclerosis. Patients with polyvascular disease experience elevated rates of cardiovascular death, myocardial infarction and stroke, especially among high-risk subgroups like those with type 2 diabetes mellitus and there is a step-wise increased risk of adverse outcomes with each additional vascular territory involved. Genetic analyses demonstrate that some individuals may carry a genetic predisposition, while others exhibit higher levels of atherogenic lipoproteins and inflammatory markers. Routine screening for asymptomatic disease is not currently recommended by major cardiovascular societies unless patients are high-risk. While there are no established protocols for escalating treatment, existing guidelines advocate for lipid-lowering therapy. Additionally, recent studies have demonstrated benefit from antithrombotic agents, such as P2Y12 inhibitors and low-dose anticoagulation, but the optimal timing and dosage of these agents has not been established, and the ischemic benefit must be balanced against the increased risk of bleeding in the polyvascular population. Due to the high prevalence and risks associated with polyvascular disease, early identification and treatment intensification are crucial to reduce disease progression. Future research is needed to develop screening protocols and determine the optimal timing and dosing of therapy to prevent ischemic events.

Construction of ferroptosis-related prediction model for pathogenesis, diagnosis and treatment of ruptured abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a dangerous cardiovascular disease, which often brings great psychological burden and economic pressure to patients. If AAA rupture occurs, it is a serious threat to patients' lives. Therefore, it is of clinical value to actively explore the pathogenesis of ruptured AAA and prevent its occurrence. Ferroptosis is a new type of cell death dependent on lipid peroxidation, which plays an important role in many cardiovascular diseases. In this study, we used online data and analysis of ferroptosis-related genes to uncover the formation of ruptured AAA and potential therapeutic targets. We obtained ferroptosis-related differentially expressed genes (Fe-DEGs) from GSE98278 dataset and 259 known ferroptosis-related genes from FerrDb website. Enrichment analysis of differentially expressed genes (DEGs) was performed by gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG). Receiver Operating characteristic (ROC) curve was employed to evaluate the diagnostic abilities of Fe-DEGs. Transcription factors and miRNAs of Fe-DEGs were identified through PASTAA and miRDB, miRWalk, TargetScan respectively. Single-sample gene set enrichment analysis (ssGSEA) was used to observe immune infiltration between the stable group and the rupture group. DGIdb database was performed to find potential targeted drugs of DEGs. GO and KEGG enrichment analysis found that DEGs mainly enriched in "cellular divalent inorganic cation homeostasis," "cellular zinc ion homeostasis," "divalent inorganic cation homeostasis," "Mineral absorption," "Cytokine - cytokine receptor interaction," "Coronavirus disease - COVID-19." Two up-regulated Fe-DEGs MT1G and DDIT4 were found to further analysis. Both single and combined applications of MT1G and DDIT4 showed good diagnostic efficacy (AUC = 0.8254, 0.8548, 0.8577, respectively). Transcription factors STAT1 and PU1 of MT1G and ARNT and MAX of DDIT4 were identified. Meanwhile, has_miR-548p-MT1G pairs, has_miR-53-3p/has_miR-181b-5p/ has_miR-664a-3p-DDIT4 pairs were found. B cells, NK cells, Th2 cells were high expression in the rupture group compared with the stable group, while DCs, Th1 cells were low expression in the rupture group. Targeted drugs against immunity, GEMCITABINE and INDOMETHACIN were discovered. We preliminarily explored the clinical significance of Fe-DEGs MT1G and DDIT4 in the diagnosis of ruptured AAA, and proposed possible upstream regulatory transcription factors and miRNAs. In addition, we also analyzed the immune infiltration of stable and rupture groups, and found possible targeted drugs for immunotherapy.

Variability in short-term mortality following repair of ruptured abdominal aortic aneurysms across centers and physicians

BACKGROUND

Variation in the care management of repairs for ruptured infrarenal abdominal aortic aneurysms between centers and physicians, such as procedural volumes, may explain differences in mortality outcomes. First, we quantified the center and physician variability associated with 30- and 90-day mortality risk after ruptured open surgical repair (rOSR) and ruptured endovascular aneurysm repair (rEVAR). Second, we explored wheter part of this variability was attributable to procedural volume at the center and physician levels.

METHODS

Two cohorts including rOSR and rEVAR procedures between 2013 and 2019 were analyzed from the Vascular Quality Initiative database. Thirty- and 90-day all-cause mortality rates were derived from linked Medicare claims data. The median odds ratio (MOR) (median mortality risk from low- to high-risk cluster) and intraclass correlation coefficient (ICC) (variability attributable to each cluster) for 30- and 90-day mortality risks associated with center and physician variability were derived using patient-level adjusted multilevel logistic regression models. Procedural volume was calculated at the center and physician levels and stratified by quartiles. The models were sequentially adjusted for volumes, and the difference in ICCs (without vs with accounting for volume) was calculated to describe the center and physician variability in mortality risk attributable to volumes.

RESULTS

We included 450 rOSRs (mean age, 74.5 ± 7.6 years; 23.5% female) and 752 rEVARs (76.4 ± 8.4 years; 26.1% female). After rOSRs, the 30- and 90-day mortality rates were 32.9% and 38.7%, respectively. No variability across centers and physicians was noted (30- and 90-day MORs ≈1 and ICCs ≈0%). Neither center nor physician volume was associated with 30-day (P = .477 and P = .796) or 90-day mortality (P = .098 and P = .559). After rEVAR, the 30- and 90-day mortality rates were 21.3% and 25.5%, respectively. Significant center variability (30-day MOR, 1.82 [95% confidence interval (CI), 1.33-2.22]; ICC, 11% [95% CI, 2%-36%]; and 90-day MOR, 1.76 [95% CI, 1.37-2.09]; ICC, 10% [95% CI, 3%-30%]), but negligeable variability across physicians (30- and 90-day MORs ≈1 and ICCs ≈0%) were noted. Neither center nor physician volume were associated with 30-day (P = .076 and P = .336) or 90-day mortality risk (P = .066 and P = .584). The center variability attributable to procedural volumes was negligeable (difference in ICCs, 1% for 30-day mortality; 0% for 90-day mortality).

CONCLUSIONS

Variability in practice from center to center was associated with short-term mortality outcomes in rEVAR, but not for rOSR. Physician variability was not associated with short-term mortality for rOSR or rEVAR. Annualized center and physician volumes did not significantly explain these associations. Further work is needed to identify center-level factors affecting the quality of care and outcomes for ruptured abdominal aortic aneurysms.

Activated clotting time-guided heparinization during open AAA surgery: a pilot study

BACKGROUND

Arterial thrombo-embolic complications (TEC) are still common during and after non-cardiac arterial procedures (NCAP). While unfractionated heparin has been used during NCAP for more than 70 years to prevent TEC, there is no consensus regarding the optimal dosing strategy. The aim of this pilot study was to test the effectiveness and feasibility of an activated clotting time (ACT)-guided heparinization protocol during open abdominal aortic aneurysm (AAA) surgery, in anticipation of a randomized controlled trial (RCT) investigating if ACT-guided heparinization leads to better clinical outcomes compared to a single bolus of 5000 IU of heparin.

METHODS

A prospective multicentre pilot study was performed. All patients undergoing elective open repair for an AAA (distal of the superior mesenteric artery) between March 2017 and January 2020 were included. Two heparin dosage protocols were compared: ACT-guided heparinization with an initial dose of 100 IU/kg versus a bolus of 5000 IU. The primary outcome was the effectiveness and feasibility of an ACT-guided heparinization protocol with an initial heparin dose of 100 IU/kg during open AAA surgery. Bleeding complications, TEC, and mortality were investigated for safety purposes.

RESULTS

A total of 50 patients were included in the current study. Eighteen patients received a single dose of 5000 IU of heparin and 32 patients received 100 IU/kg of heparin with additional doses based on the ACT. All patients who received the 100 IU/kg dosing protocol reached the target ACT of > 200 s. In the 5000 IU group, TEC occurred in three patients (17%), versus three patients (9.4%) in the 100 IU/kg group. Bleeding complications were found in six patients (33%) in the 5000 IU group and in 9 patients (28%) in the 100 IU/kg group. No mortality occurred in either group.

CONCLUSIONS

This pilot study demonstrated that ACT-guided heparinization with an initial dose of 100 IU/kg appears to be feasible and leads to adequate anticoagulation levels. Further randomized studies seem feasible and warranted to determine whether ACT-guided heparinization results in better outcomes after open AAA repair.

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.

The Role of Inflammasome in Abdominal Aortic Aneurysm and Its Potential Drugs

Abdominal aortic aneurysm (AAA) has been recognized as a serious chronic inflammatory degenerative aortic disease in recent years. At present, there is no other effective intervention except surgical treatment for AAA. With the aging of the human population, its incidence is increasing year by year, posing a serious threat to human health. Modern studies suggest that vascular chronic inflammatory response is the core process in AAA occurrence and development. Inflammasome, a multiprotein complex located in the cytoplasm, mediates the expression of various inflammatory cytokines like interleukin (IL)-1β and IL-18, and thus plays a pivotal role in inflammation regulation. Therefore, inflammasome may exert a crucial influence on the progression of AAA. This article reviews some mechanism studies to investigate the role of inflammasome in AAA and then summarizes several potential drugs targeting inflammasome for the treatment of AAA, aiming to provide new ideas for the clinical prevention and treatment of AAA beyond surgical methods.

Peak wall rupture index is associated with risk of rupture of abdominal aortic aneurysms, independent of size and sex

BACKGROUND

Information on the predictive determinants of abdominal aortic aneurysm rupture from CT angiography are scarce. The aim of this study was to investigate biomechanical parameters in abdominal aortic aneurysms and their association with risk of subsequent rupture.

METHODS

In this retrospective study, the digital radiological archive was searched for 363 patients with ruptured abdominal aortic aneurysms. All patients who underwent at least one CT angiography examination before aneurysm rupture were included. CT angiography results were analysed to determine maximum aneurysm diameter, aneurysm volume, and biomechanical parameters (peak wall stress and peak wall rupture index). In the primary survival analysis, patients with abdominal aortic aneurysms less than 70 mm were considered. Sensitivity analyses including control patients and abdominal aortic aneurysms of all sizes were performed.

RESULTS

A total of 67 patients who underwent 109 CT angiography examinations before aneurysm rupture were identified. The majority were men (47, 70%) and the median age at the time of CTA examination was 77 (71-83) years. The median maximum aneurysm diameter was 56 (interquartile range 46-65) mm and the median time to rupture was 2.13 (interquartile range 0.64-4.72) years. In univariable analysis, maximum aneurysm diameter, aneurysm volume, peak wall stress, and peak wall rupture index were all associated with risk of rupture. Women had an increased HR for rupture when adjusted for maximum aneurysm diameter or aneurysm volume (HR 2.16, 95% c.i. 1.23 to 3.78 (P = 0.007) and HR 1.92, 95% c.i. 1.06 to 3.50 (P = 0.033) respectively). In multivariable analysis, the peak wall rupture index was associated with risk of rupture. The HR for peak wall rupture index was 1.05 (95% c.i. 1.03 to 1.08) per % (P < 0.001) when adjusted for maximum aneurysm diameter and 1.05 (95% c.i. 1.02 to 1.08) per % (P < 0.001) when adjusted for aneurysm volume.

CONCLUSION

Biomechanical factors appear to be important in the prediction of abdominal aortic aneurysm rupture. Women are at increased risk of rupture when adjustments are made for maximum aneurysm diameter alone.

One-year follow-up after active aortic aneurysm sac treatment with shape memory polymer devices during endovascular aneurysm repair

OBJECTIVE

To determine the safety and efficacy of treating abdominal aortic aneurysm (AAA) sacs with polyurethane shape memory polymer (SMP) devices during endovascular aneurysm repair (EVAR), using a technique to fully treat the target lumen after endograft placement (aortic flow volume minus the endograft volume). SMP devices self-expand in the sac to form a porous scaffold that supports thrombosis throughout its structure.

METHODS

Two identical prospective, multicenter, single-arm studies were conducted in New Zealand and the Netherlands. The study population was adult candidates for elective EVAR of an infrarenal AAA (diameter of ≥55 mm in men and ≥50 mm in women). Key exclusion criteria were an inability to adequately seal a common iliac artery aneurysm, patent sac feeding vessels of >4 mm, and a target lumen volume of <20 mL or >135 mL. Target lumen volumes were estimated by subtracting endograft volumes from preprocedural imaging-based flow lumen volumes. SMP devices were delivered immediately after endograft deployment via a 6F sheath jailed in a bowed position in the sac. The primary efficacy end point was technical success, defined as filling the actual target lumen volume with fully expanded SMP at the completion of the procedure. Secondary efficacy outcome measures during follow-up were the change in sac volume and diameter, rate of type II endoleak and type I or III endoleaks, and the rate of open repair and related reinterventions, with data collection at 30 days, 6 months, and 1 year (to date). Baseline sac volumes and diameters for change in sac size analyses were determined from 30-day imaging studies. Baseline and follow-up volumes were normalized by subtraction of the endograft volume.

RESULTS

Of 34 patients treated with SMP devices and followed per protocol, 33 patients were evaluable at 1 year. Preprocedural aneurysm volume was 181.4 mL (95% confidence interval [CI], 150.7-212.1 mL) and preprocedural aneurysm diameter was 60.8 mm (95% CI, 57.8-63.9 mm). The target lumen volume was 56.3 mL (95% CI, 46.9-65.8 mL). Technical success was 100% and the ratio of SMP fully expanded volume to estimated target lumen volume was 1.4 ± 0.3. Baseline normalized sac volume and diameter were 140.7 mL (95% CI, 126.6-154.9 mL) and 61.0 mm (95% CI, 59.7-62.3 mm). The adjusted mean percentage change in normalized volume at 1 year was -28.8% (95% CI, -35.3 to -22.3%; P < .001). The adjusted mean change in sac diameter at 1 year was -5.9 mm (95% CI, -7.5 to -4.4 mm; P < .001). At 1 year, 81.8% of patients (95% CI, 64.5%-93.0%) achieved a ≥10% decrease in normalized volume and 57.6% of patients (95% CI, 39.2%-74.5%) achieved a ≥5 mm decrease in diameter. No device- or study procedure-related major adverse events occurred through 1 year after the procedure.

CONCLUSIONS

Treatment of AAA sacs with SMP devices during EVAR resulted in significant sac volume and diameter regression at 1 year with an acceptable safety profile in this prospective study.

Editor's Choice - External Validation of a Prognostic Model for Survival of Patients With Abdominal Aortic Aneurysms Treated by Endovascular Aneurysm Repair

OBJECTIVE

Current guidelines recommend diameter monitoring of small and asymptomatic abdominal aortic aneurysms (AAAs) due to the low risk of rupture. Elective AAA repair is recommended for diameters ≥ 5.5 cm in men and ≥ 5.0 cm in women. However, data supporting the efficacy of elective treatment for all patients above these thresholds are diverging. For a subgroup of patients, life expectancy might be very short, and elective AAA repair at the current threshold may not be justified. This study aimed to externally validate a predictive model for survival of patients with an asymptomatic AAA treated by endovascular aneurysm repair (EVAR).

METHODS

This was a multicentre international retrospective observational cohort study. Data were collected from four European aortic centres treating patients between 2001 and 2021. The initial model included age, estimated glomerular filtration rate (eGFR), and chronic obstructive pulmonary disease (COPD) as independent predictors for survival. Model performance was measured by discrimination and calibration.

RESULTS

The validation cohort included 1 500 patients with a median follow up of 65 months, during which 54.6% of the patients died. The external validation showed slightly decreased discrimination ability and signs of overfitting in model calibration. However, a high risk subgroup of patients with impaired survival rates was identified: octogenarians with eGFR < 60 OR COPD, septuagenarians with eGFR < 30, and septuagenarians with eGFR < 60 and COPD having survival rates of only 55.2% and 15.5% at five and 10 years, respectively.

CONCLUSION

EVAR is a valuable treatment option for AAA, especially for patients unsuitable for open repair. Nonetheless, not all these patients will benefit from EVAR, and an individualised treatment recommendation should include considerations on life expectancy. This study provides a risk stratification to identify patients who may not benefit from EVAR using the present diameter thresholds.

Clinical Impact and Determinants of Fenestration to Target Vessel Misalignment in Fenestrated Endovascular Aortic Repair

OBJECTIVE

This single centre, retrospective study (2014 - 2022) on juxta-, pararenal, or thoraco-abdominal aortic aneurysms treated by fenestrated endovascular aortic repair (FEVAR) was conducted to investigate the clinical impact and determinants of fenestration to target vessel misalignment in FEVAR.

METHODS

Pre-operative supracoeliac, pararenal, and infrarenal aortic angles were measured on three dimensional computed tomography angiography (CTA) reconstructions. Two components of misalignment were measured on the first post-operative CTA: horizontal misalignment (angle between the fenestration and the target vessel ostium on perpendicular CTA cuts) and vertical misalignment (vertical distance between the fenestration and the target vessel at its origin). Endpoints were freedom from target vessel instability (TVI) and alignment change over time.

RESULTS

Of 65 patients treated by FEVAR, 60 (202 target arteries) with juxta-, pararenal (80%), or thoraco-abdominal aortic aneurysm (20%) were included. Mean horizontal misalignment was 9 ± 12° (median 5°; IQR 0 - 16) and mean vertical misalignment was 0.7 ± 1 mm (median 0 mm, IQR 0 - 1). Freedom from TVI was 92% (95% CI 88 - 98) at 36 months. Horizontal misalignment > 15° was significantly associated with TVI (HR 5.19; 95% CI 1.54 - 17.48; p = .008); vertical misalignment did not significantly impact TVI (HR 0.99; 95% CI 0.56 - 1.73; p = .97). By multivariable analysis, pararenal aortic angle (OR 1.01 per increased degree of angulation; 95% CI 1.00 - 1.02; p = .044), bridging distance > 5 mm (OR 1.07; 95% CI 1.02 - 1.11; p = .003), and use of higher profile endografts in tortuous iliac access (OR 7.55; 95% CI 4.55 - 1.11; p = .003) were associated with clinically significant misalignment. Bridging distance > 5 mm (OR 2.00; 95% CI 1.02 - 11.29; p = .044), degree of baseline misalignment (OR 1.04; 95% CI 1.01 - 1.08; p = .036), and persistence of any primary endoleak for > 6 months (OR 5.85; 95% CI 1.23 - 29.1; p = .023) were associated with misalignment increase during follow up.

CONCLUSION

Horizontal misalignment > 15° is associated with worsened target vessel outcomes. This may occur as a result of excessive iliac access tortuosity, high pararenal aortic angulation, and bridging distance > 5 mm.

A 20-Year Analysis of Ruptured Abdominal Aortic Aneurysm Outcomes and Associated Factors in Korea

BACKGROUND

Unlike western countries, which have reported distinct decreases in incidence of ruptured abdominal aortic aneurysm (rAAA) over the last few decades, epidemiologic studies in Korea have not shown significant changes in incidence or mortality of rAAA. The purpose of this study was to analyze the changes in rAAA treatment outcomes and various associated risk factors over the past 2 decades.

METHODS

A 20-year retrospective multicenter review for rAAA cases from the period of January 2000 to December 2020 was undertaken. Preoperative, intraoperative and postoperative clinical data were extracted for patients diagnosed with rAAA. For analysis, outcomes from the early era, defined as patients treated between January 1, 2000, and December 31, 2010, were compared with outcomes from the late era, defined as patients treated between January 1, 2011, and December 31, 2020.

RESULTS

The total in-hospital mortality was 34.1% in the early era compared to 44.8% in the late era. Patients in the late era were older than those in the early era (75.2 ± 10.3 years vs. 70.3 ± 8.9 years; P = 0.009). Treatment with rAAA endovascular aneurysm repair increased from 2.3% in early to 13.8% in late era (P = 0.031). In the early era, more patients were operated by experienced surgeons than the late era (78.1% vs. 45.9%; P = 0.002). The emergency room to operating room time did not show improvement over the 20 years.

CONCLUSIONS

The results indicate that mortality rate of rAAA in Korea has not changed over the last 2 decades. The study suggests the need for national preventive strategies, improved systemic coordination, and potential centralization of vascular services to enhance survival rates for rAAA.

Propensity score analysis demonstrates no long term survival benefit from contemporary endovascular aneurysm repair compared to open in Aotearoa New Zealand

BACKGROUND

Current guidelines for AAA management are based on landmark trials comparing EVAR and open aneurysm repair (OAR) conducted more than 20 years ago. Important advancements have been made in peri-operative care but the impact of EVAR and OAR on long-term patient survival has not been well reported using contemporary data. The objective of this study was to compare the short and long-term outcomes of OAR and EVAR in the recent era.

METHODS

This retrospective observational study included all patients undergoing intact AAA repair in NZ from 1st of January 2011 until 31st of December 2019. Data was collected from national administrative and clinical vascular databases and matched using unique identifiers. Time-to-event survival analyses was conducted using cox proportional hazard models to adjust for confounders and propensity score matching were used.

RESULTS

Two thousand two hundred and ninety-seven patients had an intact AAA repair with a median (IQR) age of 75 (69-80) years; 494 (21.2%) patients were females and 1206 (53%) underwent EVAR. The 30-day mortality for OAR and EVAR was 4.8% and 1.2%. The median (IQR) follow up was 5.2 (2.3-9.2) years. After propensity matching for co-variates, the study cohort consisted of 835 patients in each matched group. Patients undergoing EVAR had a higher overall mortality (HR 1.48 (95% CI: 1.26-1.74) after adjusting for confounders compared to OAR.

CONCLUSION

Analysis of survival following EVAR and OAR in the current era demonstrates that patients that underwent EVAR had a lower 30-day mortality. However, in the long-term after adjusting for confounders OAR had a better overall survival.

Left Renal Artery Chronic Occlusion in the Setting of Extensive Intraprosthetic Mural Thrombus in an Abdominal Aortic Endograft

Thrombotic deposits within aortic endograft post-endovascular aortic aneurysm repair (EVAR) is a fairly well-recognized complication, yet their clinical significance remains inadequately understood. We present a rare case of extensive mural thrombus formation in an oncologic patient with a history of EVAR, emphasizing the importance of lifelong surveillance in abdominal aortic aneurysm (AAA)-EVAR patients. A 75-year-old female was admitted with refractory hypertension secondary to a medium-sized AAA, which exhibited an extensive mural thrombus, contributing to atrophic changes in the left kidney and likely chronic occlusion of the left renal artery. Factors contributing to thrombus formation generally include endograft configuration, aneurysm diameter, and patient-specific characteristics, such as a pro-thrombotic status conferred by metastatic lung cancer. This case underscores the necessity for comprehensive surveillance strategies post-EVAR. Recommendations advocate for a 30-day follow-up and lifelong annual surveillance, employing modalities such as color duplex ultrasound for detection of endoleaks and sac enlargement, with selective use of CT imaging. This case underscores the importance of continued vigilance and surveillance in patients undergoing EVAR, particularly those with complex medical histories, to mitigate potential long-term complications and optimize patient outcomes.

Extravascular administration of IGF1R antagonists protects against aortic aneurysm in rodent and porcine models

An abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease. We identified plasma insulin-like growth factor 1 (IGF1) as an independent risk factor in patients with AAA by correlating plasma IGF1 with risk. Smooth muscle cell- or fibroblast-specific knockout of Igf1r, the gene encoding the IGF1 receptor (IGF1R), attenuated AAA formation in two mouse models of AAA induced by angiotensin II infusion or CaCl2 treatment. IGF1R was activated in aortic aneurysm samples from human patients and mice with AAA. Systemic administration of IGF1C, a peptide fragment of IGF1, 2 weeks after disease development inhibited AAA progression in mice. Decreased AAA formation was linked to competitive inhibition of IGF1 binding to its receptor by IGF1C and modulation of downstream alpha serine/threonine protein kinase (AKT)/mammalian target of rapamycin signaling. Localized application of an IGF1C-loaded hydrogel was developed to reduce the side effects observed after systemic administration of IGF1C or IGF1R antagonists in the CaCl2-induced AAA mouse model. The inhibitory effect of the IGF1C-loaded hydrogel administered at disease onset on AAA formation was further evaluated in a guinea pig-to-rat xenograft model and in a sheep-to-minipig xenograft model of AAA formation. The therapeutic efficacy of IGF1C for treating AAA was tested through extravascular delivery in the sheep-to-minipig model with AAA established for 2 weeks. Percutaneous injection of the IGF1C-loaded hydrogel around the AAA resulted in improved vessel flow dynamics in the minipig aorta. These findings suggest that extravascular administration of IGF1R antagonists may have translational potential for treating AAA.

Octogenarians fare better under local anesthesia for elective endovascular aortic aneurysm repair

OBJECTIVE

With an aging patient population, an increasing number of octogenarians are undergoing elective endovascular abdominal aortic aneurysm repair (EVAR) in the United States. Multiple studies have shown that, for the general population, use of local anesthetic (LA) for EVAR is associated with improved short-term and long-term outcomes as compared with performing these operations under general anesthesia (GA). Therefore, this study aimed to study the association of LA for elective EVARs with perioperative outcomes, among octogenarians.

METHODS

The Vascular Quality Initiative database (2003-2021) was used to conduct this study. Octogenarians (Aged ≥80 years) were selected and sorted into two study groups: LA (Group I) and GA (Group II). Our primary outcomes were length of stay and mortality. Secondary outcomes included operative time, estimated blood loss, return to operating room, cardiopulmonary complications, and discharge location.

RESULTS

Of the 16,398 selected patients, 1197 patients (7.3%) were included in Group I, and 15,201 patients (92.7%) were in Group II. Procedural time was significantly shorter for the LA group (114.6 vs 134.6; P < .001), as was estimated blood loss (152 vs 222 cc; P < .001). Length of stay was significantly shorter (1.8 vs 2.6 days; P < .001), and patients were more likely to be discharged home (LA 88.8% vs GA 86.9%; P = .036) in the LA group. Group I also experienced fewer pulmonary complications; only 0.17% experienced pneumonia and 0.42% required ventilator support compared with 0.64% and 1.02% in Group II, respectively. This finding corresponded to fewer days in the intensive care unit for Group I (0.41 vs 0.69 days; P < .001). No significant difference was seen in 30-day mortality cardiac, renal, or access site-related complications. Return to operating room was also equivocal between the two groups. Multivariate regression analysis confirmed GA was associated with a significantly longer length of stay and significantly higher rates of non-home discharge (adjusted odds ratio [AOR], 1.59; P < .001 and AOR, 1.40; P = .025, respectively). When stratified by the New York Heart Association classification system, classes I, II, III, and IV (1.55; P < .001; 1.26; P = .029; 2.03; P < .001; 4.07; P < .001, respectively) were associated with significantly longer hospital stays.

CONCLUSIONS

The use of LA for EVARs in octogenarians is associated with shorter lengths of stay, fewer respiratory complications, and home discharge. These patients also experienced shorter procedure times and less blood loss. There was no statistically significant difference in 30-day mortality, return to operating room, or access-related complications. LA for octogenarians undergoing EVAR should be considered more frequently to shorten hospital stays and decrease complication rates.

Controlling the nutritional status score: a new tool for predicting postoperative mortality in patients with infrarenal abdominal aortic aneurysm treated with endovascular aneurysm repair

Background

AAA is a fatal condition that commonly occurs during vascular surgery. Nutritional status exerts a significant influence on the prognosis of various pathological conditions Scores from the CONUT screening tool have been shown to predict outcomes of certain malignancies and chronic diseases. However, the ramifications of nutritional status on AAA patients undergoing EVAR have not been elucidated in prior studies. In this study, we aimed to elucidate the correlation between CONUT scores and postoperative prognostic outcomes in patients with AAA undergoing EVAR.

Methods

This was a retrospective review of 177 AAA patients treated with EVAR from June 2018 to November 2019 in a single center. Patient characteristics, CONUT scores, and postoperative status were collected. These patients were stratified into groups A and B according to CONUT scores. Subsequently, a comparative analysis of the baseline characteristics between the two cohorts was conducted. Cox proportional hazards and logistic regression analyses were employed to identify the autonomous predictors of mid-term mortality and complications, respectively.

Results

Compared with group A, patients in group B had higher midterm mortality (p < 0.001). Univariate analysis showed that CONUT scores; respiratory diseases; stent types; preoperative Hb, CRP, PT, and Fb levels were risk factors for death. Multivariate analysis confirmed that CONUT score [HR, 1.276; 95% CI, 1.029-1.584; p = 0.027] was an independent risk factor for mortality. Logistic regression analysis showed that prior arterial disease, smoking, and D-dimer levels were risk factors, although multivariate analysis showed smoking (OR, 3.492; 95% CI, 1.426-8.553; p = 0.006) was an independent risk factor. Kaplan-Meier curves showed that patients in group B had shorter mid-term survival than those in group A (log-rank p < 0.001).

Conclusion

Malnutrition was strongly associated with mid-term mortality in patients with infrarenal AAA treated with EVAR.

Local Anesthesia for Endovascular Repair of Abdominal Aortic Aneurysm Allows for Accurate Graft Deployment with Durable Results

BACKGROUND

Local anesthesia (LA) is sparsely used in endovascular aneurysm repair (EVAR) despite short-term benefit, likely secondary to concerns over patient movement preventing accurate endograft deployment. The objective of this study is to examine the association between anesthesia type and endoleak, sac regression, reintervention, and mortality.

METHODS

The Vascular Quality Initiative database was queried for all EVAR cases from 2014 to 2022. Patients were included if they underwent percutaneous elective EVAR with anatomical criteria within instructions for use of commercially approved endografts. Multivariable logistic regression with propensity score weighting was used to determine the association between anesthesia type on the risk of any endoleak noted by intraoperative completion angiogram and sac regression. Multivariable survival analysis with propensity score weighting was used to determine the association between anesthesia type and endoleak at 1 year, long-term reintervention, and mortality.

RESULTS

Thirteen thousand nine hundred thirty two EVARs met inclusion criteria: 1,075 (8%) LA and 12,857 (92%) general anesthesia (GA). On completion angiogram, LA was associated with fewer rates of any endoleaks overall (16% vs. 24%, P < 0.001). On multivariable analysis with propensity score weighting, LA was associated with similar adjusted odds of any endoleak on intraoperative completion angiogram (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.47-0.68) as well as combined type 1a and type 1b endoleaks (OR 0.72, 95% CI 0.47-1.09). Follow-up computed tomography imaging at 1 year was available for 4,892 patients, 377 (8%) LA and 4,515 (92%) GA. At 1 year, LA was associated with similar rate of freedom from any endoleaks compared to GA (0.66 [95% CI 0.63-0.69] vs. 0.71 [95% CI 0.70-0.72], P = 0.663) and increased rates of sac regression (50% vs. 45%, P = 0.040). On multivariable analysis with propensity score weighting, LA and GA were associated with similar adjusted odds of sac regression (OR 1.22, 95% CI 0.97-1.55). LA and GA had similar rates of endoleak at 1 year (hazard ratio [HR] 0.14, 95% CI 0.63-1.07); however, LA was associated with decreased hazards of combined type 1a and 1b endoleaks at 1 year (HR 0.87, 95% CI 0.80-0.96). LA and GA had similar adjusted long-term reintervention rate (HR 0.77, 95% CI 0.44-1.38) and long-term mortality (HR 1.100, 95% CI 079-1.25).

CONCLUSIONS

LA is not associated with increased adjusted rates of any endoleak on completion angiogram or at 1-year follow-up compared to GA. LA is associated with decreased adjusted rates of type 1a and type 1b endoleak at 1 year, but similar rates of sac regression, long-term reintervention, and mortality. Concerns for accurate graft deployment should not preclude use of LA and LA should be increasingly considered when deciding on anesthetic type for standard elective EVAR.

Computed Tomography Angiography After Transcatheter and Surgical Aortic Interventions

This comprehensive article reviews the complex realm of aortic surgical and endovascular interventions, focusing on the aortic root, ascending aorta, aortic arch, descending aorta, and abdominal aorta. It outlines the nuances of various procedures, emphasizing the importance of computed tomography angiography acquisition for an accurate assessment. Detailed discussions encompass expected postsurgical/endovascular findings and complications, covering various scenarios, from hematoma and infection to pseudoaneurysms and graft-related issues. This article serves as a crucial resource for radiologists, offering invaluable insights into the complexities of aortic interventions and their subsequent imaging, fostering a comprehensive understanding of diagnostic and management strategies.

Prognostic value of left ventricular systolic function before vascular surgery: a systematic review

BACKGROUND

Vascular surgery carries a high risk of post-operative cardiac complications. Recent studies have shown an association between asymptomatic left ventricular systolic dysfunction and increased risk of major adverse cardiovascular events (MACE). This systematic review aims to evaluate the prognostic value of left ventricular function as determined by left ventricular ejection fraction (LVEF) measured by resting echocardiography before vascular surgery.

METHODS

This review conformed to PRISMA and MOOSE guidelines. PubMed, OVID Medline and Cochrane databases were searched from inception to 27 October 2022. Eligible studies assessed vascular surgery patients, with multivariable-adjusted or propensity-matched observational studies measuring LVEF via resting echocardiography and providing risk estimates for outcomes. The primary outcomes measures were all-cause mortality and congestive heart failure at 30 days. Secondary outcome included the composite outcome MACE.

RESULTS

Ten observational studies were included (4872 vascular surgery patients). Studies varied widely in degree of left ventricular systolic dysfunction, symptom status, and outcome reporting, precluding reliable meta-analysis. Available data demonstrated a trend towards increased incidence of all-cause mortality, congestive heart failure and MACE in patients with pre-operative LVEF <50%. Methodological quality of the included studies was found to be of moderate quality according to the Newcastle Ottawa Checklist.

CONCLUSION

The evidence surrounding the prognostic value of LVEF measurement before vascular surgery is currently weak and inconclusive. Larger scale, prospective studies are required to further refine cardiac risk prediction before vascular surgery.

Size thresholds for repair of abdominal aortic aneurysms warrant reconsideration

BACKGROUND

The historical size threshold for abdominal aortic aneurysm (AAA) repair is widely accepted to be 5.5 cm for men and 5.0 cm for women. However, contemporary AAA rupture risks may be lower than historical benchmarks, which has implications for when AAAs should be repaired. Our objective was to use contemporary AAA rupture rates to inform optimal size thresholds for AAA repair.

METHODS

We used a Markov chain analysis to estimate life expectancy for patients with AAA. The primary outcome was AAA-related mortality. We estimated survival using Social Security Administration life tables and published contemporary AAA rupture estimates. For those undergoing repair, we modified survival estimates using data from the Vascular Quality Initiative and Medicare on complications, late rupture, and open conversion. We used this model to estimate the AAA repair size threshold that minimizes AAA-related mortality for 60-year-old average-health men and women. We performed a sensitivity analysis of poor-health patients and 70- and 80-year-old base cases.

RESULTS

The annual risk of all-cause mortality under surveillance for a 60-year-old woman presenting with a 5.0 cm AAA using repair thresholds of 5.5 cm, 6.0 cm, 6.5 cm, and 7.0 cm was 1.7%, 2.3%, 2.7%, and 2.8%, respectively. The corresponding risk for a man was 2.3%, 2.9%, 3.3%, and 3.4% for the same repair thresholds, respectively. For a 60-year-old average-health woman, an AAA repair size of 6.1 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 5.7 cm to 7.1 cm. For a 60-year-old average-health man, an AAA repair size of 6.9 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 6.0 cm to 7.4 cm. Women in poor health, at various age strata, had optimal AAA repair size thresholds that were >6.5 cm, whereas men in poor health, at all ages, had optimal repair size thresholds that were >8.0 cm.

CONCLUSIONS

The optimal threshold for AAA repair is more nuanced than a discrete size. Specifically, there appears to be a range of AAA sizes for which repair is reasonable to minmized AAA-related mortality. Notably, they all are greater than current guideline recommendations. These findings would suggest that contemporary AAA size thresholds for repair should be reconsidered.

Machine learning-based prediction of abdominal aortic aneurysms for individualized patient care

OBJECTIVE

The United States Preventative Services Task Force guidelines for screening for abdominal aortic aneurysms (AAA) are broad and exclude many at risk groups. We analyzed a large AAA screening database to examine the utility of a novel machine learning (ML) model for predicting individual risk of AAA.

METHODS

We created a ML model to predict the presence of AAAs (>3 cm) from the database of a national nonprofit screening organization (AAAneurysm Outreach). Participants self-reported demographics and comorbidities. The model is a two-layered feed-forward shallow network. The ML model then generated AAA probability based on patient characteristics. We evaluated graphs to determine significant factors, and then compared those graphs with a traditional logistic regression model.

RESULTS

We analyzed a cohort of 10,033 patients with an AAA prevalence of 2.74%. Consistent with logistic regression analysis, the ML model identified the following predictors of AAA: Caucasian race, male gender, advancing age, and recent or past smoker with recent smoker having a more profound affect (P < .05). Interestingly, the ML model showed body mass index (BMI) was associated with likelihood of AAAs, especially for younger females. The ML model also identified a higher than predicted risk of AAA in several groups, including female nonsmokers with cardiac disease, female diabetics, those with a family history of AAA, and those with hypertension or hyperlipidemia at older ages. An elevated BMI conveyed a higher than expected risk in male smokers and all females. The ML model also identified a complex relationship of both diabetes mellitus and hyperlipidemia with gender. Family history of AAA was a more important risk factor in the ML model for both men and women too.

CONCLUSIONS

We successfully developed an ML model based on an AAA screening database that unveils a complex relationship between AAA prevalence and many risk factors, including BMI. The model also highlights the need to expand AAA screening efforts in women. Using ML models in the clinical setting has the potential to deliver precise, individualized screening recommendations.

Case report - Computed tomography diagnosis of an abdominal aortic aneurysm complicated with primary aortoduodenal fistula

Abdominal aortic aneurysm has been described as a rare condition touching 1% of the population over the age of 50 years with a high percentage of mortality. Aneurysms progress in size, causing deadly complications such as ruptures and fistulas. Computed tomography angiography is considered the gold standard imaging exam for the evaluation of abdominal aortic aneurysms and their complications. We report the case of an elderly patient admitted to the emergency room due to recurrent gastrointestinal bleeding. The computed tomography imaging findings were in favor of an abdominal aortic aneurysm complicated with a primary aortoduodenal fistula.