Abdominal Aortic Aneurysm Diameter Research Articles

Abdominal aortic aneurysm growth rates in patients undergoing local ultrasound surveillance.

Abdominal aortic aneurysm ultrasound surveillance varies between hospitals in the United Kingdom. University Hospitals Bristol and Weston adopt a 6-monthly surveillance interval for 4.5-4.9 cm abdominal aortic aneurysm, which is a deviation from nationally recommended 3-monthly intervals. Assessment of abdominal aortic aneurysm growth rate, and the concurrent impact of abdominal aortic aneurysm risk factors and medications prescribed for risk factors, may inform whether this change in surveillance intervals is safe and appropriate. This analysis was conducted retrospectively. A total of 1312 abdominal aortic aneurysm ultrasound scans from 315 patients between January 2015 and March 2020 were split into 0.5 cm groups, ranging from 3.0 to 5.5 cm. Abdominal aortic aneurysm growth rate was assessed with one-way analysis of variance. The impact of risk factors and risk factor medication on abdominal aortic aneurysm growth rate was analysed using multivariate and univariate linear regression and Kruskal-Wallis tests. Patient cause of death among surveillance patients was recorded. Abdominal aortic aneurysm growth rate was significantly associated with increased abdominal aortic aneurysm diameter (p < 0.001). There was a significant whole-group reduction in growth rate from 0.29 to 0.19 cm/year in diabetics compared to non-diabetics (p = 0.02), supported by univariate linear regression (p = 0.04). In addition, gliclazide patients had lower growth rate compared to patients not on the medication (p = 0.04). One abdominal aortic aneurysm rupture occurred <5.5 cm resulting in death. Abdominal aortic aneurysm measuring 4.5-4.9 cm had a mean growth rate of 0.3 cm/year (± 0.18 cm/year). Therefore, mean growth rate and variability suggest patients are unlikely to surpass surgical threshold of 5.5 cm between the 6-monthly surveillance scans, supported by low rupture rates. This suggests the surveillance interval for 4.5-4.9 cm abdominal aortic aneurysm is a safe and appropriate deviation from national guidance. In addition, it may be pertinent to consider diabetic status when designing surveillance intervals.

A Systematic Review and Meta-Analysis of Laparoscopic Ligation of the Inferior Mesenteric Artery for the Treatment of Type II Endoleaks.

Type II endoleak (T2E), often generated by persistent retrograde flow through the inferior mesenteric artery (IMA) is the most frequent complication following endovascular aortic aneurysm repair (EVAR). T2E treatment revolves around transarterial and translumbar embolization of the feeding artery and/or sac, with mediocre results. The aim of this study is to assess the safety feasibility and efficacy of laparoscopic IMA ligation for the treatment of T2E. We conducted a systematic electronic research on Medline, Scopus, EMBASE, and Cochrane Library according to Preferred Reporting Items for Systematic Review and Meta-Analysis protocol (PRISMA) for articles published up to February 2022, describing laparoscopic IMA ligation for the treatment of T2E. Publications describing hand assisted or prophylactic IMA ligation were excluded. A metanalysis was performed utilizing both the random and common effects model and the DerSimonian and Laird method. Additionally, we carried out a post hoc power analysis. Fifteen studies, including one prospective case series (CS), five retrospective CS and nine case reports, including 33 patients (91% male) met the inclusion criteria. The mean abdominal aortic aneurysm diameter at the time of diagnosis was 58.8 mm. The mean operational duration was 117.5 minutes. The mean follow-up for the included studies was 17 months. The mean reported time of T2E identification was 9.1 months post-intervention, while the mean reported aneurysmal sac diameter increase at the time of diagnosis was 11.5 mm. T2E type a (T2aE) and type b (T2bE) patterns were 57.6% and 42.4% respectively. Six CS incorporating 24 patients were included in the meta-analysis. The pooled technical success and postoperative mortality rates are 100% (95% CI: 93.13-100), ( = 0.0%, p = 0.99) (power = 99%) and 0.00% (95% CI: 0.00-6.87) ( = 0.0%, p = 0.99). The pooled reintervention and conversion to open surgical repair rates are 15.08% (95% CI: 0.79-37.28), ( = 0.0%, p = 0.66) (power = 13.6%), and 0.69% (95% CI: 0.00-14.80) ( = 0.0%, p = 0.99) (power = 7.05%) respectively. We demonstrated the safety and feasibility of IMA ligation for the treatment of T2E. Definitive conclusions about its efficacy cannot be drawn due to underpowered results warrantying further research. Identification and proper classification of T2E remain an obstacle affecting treatment outcomes and reintervention rates throughout the entire spectrum of available treatments.

MR Elastography of Abdominal Aortic Aneurysms: Relationship to Aneurysm Events.

Background Abdominal aortic aneurysm (AAA) diameter remains the standard clinical parameter to predict growth and rupture. Studies suggest that using solely AAA diameter for risk stratification is insufficient. Purpose To evaluate the use of aortic MR elastography (MRE)-derived AAA stiffness and stiffness ratio at baseline to identify the potential for future aneurysm rupture or need for surgical repair. Materials and Methods Between August 2013 and March 2019, 72 participants with AAA and 56 healthy participants were enrolled in this prospective study. MRE examinations were performed to estimate AAA stiffness and the stiffness ratio between AAA and its adjacent remote normal aorta. Two Cox proportional hazards models were used to assess AAA stiffness and stiffness ratio for predicting aneurysmal events (subsequent repair, rupture, or diameter >5.0 cm). Log-rank tests were performed to determine a critical stiffness ratio suggesting high-risk AAAs. Baseline AAA stiffness and stiffness ratio were studied using Wilcoxon rank-sum tests between participants with and without aneurysmal events. Spearman correlation was used to investigate the relationship between stiffness and other potential imaging markers. Results Seventy-two participants with AAA (mean age, 71 years ± 9 [SD]; 56 men and 16 women) and 56 healthy participants (mean age, 42 years ± 16; 27 men and 29 women) were evaluated. In healthy participants, aortic stiffness positively correlated with age (ρ = 0.44; P < .001). AAA stiffness (event group [n = 21], 50.3 kPa ± 26.5 [SD]; no-event group [n = 21], 86.9 kPa ± 52.6; P = .01) and the stiffness ratio (event group, 0.7 ± 0.4; no-event group, 2.0 ± 1.4; P < .001) were lower in the event group than the no-event group at a mean follow-up of 449 days. AAA stiffness did not correlate with diameter in the event group (ρ = -0.06; P = .68) or the no-event group (ρ = -0.13; P = .32). AAA stiffness was inversely correlated with intraluminal thrombus area (ρ = -0.50; P = .01). Conclusion Lower abdominal aortic aneurysm stiffness and stiffness ratio measured with use of MR elastography was associated with aneurysmal events at a 15-month follow-up. © RSNA, 2022 See also the editorial by Sakuma in this issue.

Hemostatic Biomarkers and Volumetry Help to Identify High-Risk Abdominal Aortic Aneurysms.

Predicting the progression of small aneurysms is a main challenge in abdominal aortic aneurysm (AAA) management. The combination of circulating biomarkers and image techniques might provide an alternative for risk stratification. We evaluated the association of plasma TAT complexes (TAT) and D-dimer with AAA severity in 3 groups of patients: group 1, without AAA (n = 52), group 2, AAA 40–50 mm (n = 51) and group 3, AAA > 50 mm (n = 50). TAT (p < 0.001) and D-dimer (p < 0.001) were increased in patients with AAA (groups 2 and 3) vs. group 1. To assess the association between baseline TAT and D-dimer concentrations, and AAA growth, aortic diameter and volume (volumetry) were measured by computed tomography angiography (CTA) in group 2 at recruitment (baseline) and 1-year after inclusion. Baseline D-dimer and TAT levels were associated with AAA diameter and volume variations at 1-year independently of confounding factors (p ≤ 0.044). Additionally, surgery incidence, recorded during a 4-year follow-up in group 2, was associated with larger aneurysms, assessed by aortic diameter and volumetry (p ≤ 0.036), and with elevated TAT levels (sub-hazard ratio 1.3, p ≤ 0.029), while no association was found for D-dimer. The combination of hemostatic parameters and image techniques might provide valuable tools to evaluate AAA growth and worse evolution.

Association Between Blood Flow Pattern and Rupture Risk of Abdominal Aortic Aneurysm Based on Computational Fluid Dynamics

This study aimed to derive a novel classification of blood flow pattern in abdominal aortic aneurysms (AAA) based on computational fluid dynamics (CFDs), and to determine the predictive value of flow patterns in AAA rupture. This was an age and sex matched case control study. Cases were identified as patients who underwent emergency endovascular or open repair due to ruptured or AAA at risk of impending rupture. Controls were age and sex matched with patients with an AAA who were asymptomatic and had a confirmed unruptured AAA from computed tomography angiography images from the same period. Classification of blood flow pattern (type I: non-helical main flow channel with multiple vortices; type II: non-helical main flow channel with single vortices; and type III, helical main flow channel with helical vortices) and haemodynamic parameters (areas of low wall shear stress [AlowWSS], aneurysm pressure drop [Δ pressure], etc) were derived from CFD analyses. Multivariable regression was used to determine independent AAA rupture risk factors. The incremental discriminant and reclassification abilities for AAA rupture were compared among different models. Fifty-three ruptured and 53 intact AAA patients were included. Ruptured AAA showed a higher prevalence of type III flow pattern than intact AAA (60.4% vs. 15.1%; p < .001). Type III flow pattern was associated with a significantly increased risk of aneurysm rupture (odds ratio 10.22, 95% confidence interval 3.43 - 30.49). Among all predicting models, the combination of AAA diameter, haemodynamic parameters (AlowWSS or Δ pressure), and flow pattern showed highest discriminant abilities in both the overall population (c-index= 0.862) and subgroup patients with AAAs < 55 mm (c-index= 0.972). Compared with AAA diameter, adding the flow pattern could significantly improve the reclassification abilities in both the overall population (net reclassification index [NRI]= 0.321; p < .001) and the subgroup of AAAs < 55 mm (NRI= 0.732; p < .001). Type III flow pattern was associated with a significantly increased risk of AAA rupture. The integration of blood flow pattern may improve the identification of high risk aneurysms in both overall population and in those with AAAs < 55 mm.

Predictive Parameters for Rupture in Abdominal Aortic Aneurysms

The current screening and management guidelines for abdominal aortic aneurysms (AAAs) are based on maximal aortic diameter criteria. This study compared the aortic measurements between ruptured and intact AAAs to identify the prognostic markers for rupture. Patients treated for AAAs at Thomas Jefferson University Hospital from 2014 to 2021 were randomly selected from intact AAAs (iAAAs), ruptured AAAs (rAAAs), and no aortic pathology (NP) groups. Preoperative computed tomography angiography studies were retrospectively measured using Aquarius iNtuition (TeraRecon Inc, Durham, NC). The maximal diameter, length, mural thrombus volume (MTV), and Hounsfield calcification were measured from the lowest renal artery to the femoral artery. The aortic height index (AHI = maximal AAA diameter + length/height) was calculated to control for height. One-way analysis of variance, followed by Tukey’s multiple comparison tests and Pearson’s correlation, was performed using Prism, version 9.3.1 (GraphPad, San Diego, CA). Computed tomography angiography from 45 patients (age, 69.40 ± 8.28 years; 86.6% male) were measured for the iAAA (n = 19; 42.2%), rAAA (n = 16; 35.6%), and NP (n = 10; 22.2%) groups. Compared with those with iAAAs, the maximal AAA diameter (7.71 cm vs 6.19 cm; P = .022) and MTV (180.8 cm3 vs 91.79 cm3; P = .0323, Fig 1) was larger for the rAAA patients. The infrarenal aortic length correlated positively with the AAA diameter [r(43) = 0.66; P < .0001; Fig 2) and an increase in AAA diameter compared with NP (rAAA, 12.89 cm; iAAA, 13.03 cm; NP, 9.75 cm; P < .0001). The AHI was elevated in the rAAA compared with the iAAA patients (4.50 cm/m vs 3.43 cm/m; P = .0102; Fig 1). No other parameter differed between the rAAA and iAAA patients. Our study has demonstrated that the AAA diameter, MTV, and AHI are significant predictors of rupture of AAAs. Additionally, the infrarenal aortic length might be a viable prognostic marker for AAA vessel wall strength, warranting further investigation. These results will assist in identifying patients at high risk of rupture.Fig 2Abdominal aortic aneurysm (AAA) diameter vs length correlation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Endoleak Type III and COVID-19: A Lethal Combination

A 72 year old man presented with new onset intermittent claudication and weak femoral pulses bilaterally. After endovascular repair of a 6.0 cm abdominal aortic aneurysm (AAA) in 2018 (AFX2 plus Vela, Endologix, Irvine, CA, USA), the patient discontinued follow up after three months with a stable aneurysm. Computed tomography angiography showed AAA diameter increase to 6.8 cm and component disconnection (type III endoleak, arrow, A). Decreased main body perfusion caused claudication (arrow, B). Open repair risk was considered too high because of an active COVID-19 infection. While waiting for endovascular materials, the patient died in hospital from AAA rupture, confirmed by autopsy.Image 1

Cohort Study Examining the Association of Optimal Blood Pressure Control at Entry With Infrarenal Abdominal Aortic Aneurysm Growth.

Background and AimThe benefit of controlling cardiovascular risk factors in slowing the progression of small abdominal aortic aneurysm (AAA) is controversial. This study investigated the association of optimal blood pressure control at entry with the growth of small AAA.Methods and ResultsA total of 1,293 patients with initial AAA diameter <50 mm were followed by a median 5 (inter-quartile range, IQR, 3–7) ultrasound scans for a median of 3.6 years (IQR 1.8, 5.3). Optimal blood pressure control was defined as blood pressure ≤140/90 mmHg at recruitment. The association of optimal blood pressure control at entry with AAA growth was assessed using linear mixed effects models adjusted for established risk factors of AAA growth and factors which were unequally distributed among the blood pressure groups. Optimal blood pressure control at entry was not significantly associated with AAA growth. In the risk factor adjusted model the mean difference in AAA growth between blood pressure groups was 0.04 mm/year (95% CI −0.20, 0.13; p = 0.65). The results were similar in sensitivity analyses excluding outliers or focused on systolic or diastolic blood pressure alone.ConclusionsThis observational study suggests that optimal blood pressure control at entry is not associated with slower AAA growth.

Intermittent Hypoxia Promotes the Development of Abdominal Aortic Aneurysm in Male Mice

IntroductionIntermittent hypoxia (IH) is one of the hallmarks of obstructive sleep apnea (OSA). OSA is highly prevalent among patients with abdominal aortic aneurysm (AAA). However, it remains unknown whether IH is a risk factor for the development and faster expansion of AAA. The goal of this study was to determine whether exposure to chronic IH mimicking OSA increases the susceptibility to angiotensin (Ang) II‐induced AAA in mice.MethodsFour‐ to six‐week‐old male C57BL/6 mice (n = 20/group) were subjected to IH (6.5%‐21% O2, 90 s/cycle, 12 h/day during daylight) or room air (21% O2, 24 h/day) for 6 months. During the final 14 days of IH or room air (RA) exposures, 10 mice from each group were infused with Ang II (1000 ng/kg/minute) using a subcutaneously implanted osmotic minipump to induce AAA. Sham surgery was performed in control mice (n = 10/group). Outcome was assessed by transabdominal ultrasound imaging of the abdominal aorta using a Vevo 2100 imaging system followed by histopathological examination.ResultsUltrasound imaging revealed increased abdominal aortic diameter in RA mice following Ang II infusion compared to sham mice. Exposure to IH significantly augmented the Ang II‐induced increase in aortic diameter and incidence of AAA compared to RA Ang II mice. Histologically, IH along with Ang II infusion augmented medial elastin depletion and accumulation of collagen in the aorta. Additionally, IH was also associated with the pathological process of extensive matrix degradation as evidenced by increased matrix metalloproteinase (MMP9) and a disintegrin and metalloproteinase (Adam)17 expression in the aorta following Ang II infusion.ConclusionsIH exposures simulating OSA promote the development of AAA. Clarification of the underlying molecular mechanisms may reveal novel therapeutic targets for the management of AAA.

Accuracy of Point-of-Care Ultrasound in Follow Up Abdominal Aortic Aneurysm Imaging.

Point-of-care ultrasound (POCUS) has been reported as a valuable tool for bedside diagnoses of abdominal Aortic Aneurysms (AAA). However, no data exist regarding POCUS in measuring follow-up AAA diameter studies in patients with existing AAAs. The purpose of this study was to determine the variability of aortic measurements performed by a non-physician using POCUS vs standard of care (SOC) measurements by a registered vascular technologist or an abdominal/pelvic CT scan. A prospective observational ultrasound study was performed from 1/1/2019 to 3/31/2021 on patients with a diagnosis of an AAA (≥3.0cm). A research coordinator (non-physician) underwent a 3-hour training session in ultrasound operation and basic human anatomy to measure AAA diameter. The maximum aortic diameter was documented and compared to measurements obtained by SOC ultrasonography or CT scan. The POCUS and SOC ultrasounds were separated by no more than 90 days. Clinical risk factors including age, race, body mass index, coronary artery disease, hypertension, peripheral vascular disease, cerebrovascular disease, diabetes, and current smoking were also collected. Eighty-one patients (mean age: 73.6 ± 5.8years, body mass index: 29.5 ± 6.2kg/m2) were being followed in a vascular clinic and underwent both a POCUS and SOC ultrasounds. One indeterminant study was reported in identifying an AAA diagnosis, due to an overlying colostomy. The average follow-up time from initial screening aortic diameter to POCUS was 4.4 ± 3.7years. Overall average aortic diameter measurements obtained were 4.1 ± .9cm for POCUS and 4.0 ± .9cm for SOC (P = NS). Average difference in aortic measurement for POCUS and SOC was -.1 ± .3cm. POCUS is an accurate method to follow AAA diameter in patients. POCUS could improve patient follow up with AAA diameter measurements, streamline care and reduce overall burden for both patients and Radiology Departments in assessing follow up AAA diameters.

Positive association between calcium channel blocker treatment and persistent type II endoleak.

Type II endoleaks are the most common complication occurring after endovascular abdominal aortic aneurysm repair (EVAR). The aims of our study were to evaluate the impact of persistent type II endoleak on sac dynamics post-EVAR, and to study the association between non-anatomical factors including polymorphisms associated with abdominal aortic aneurysm (AAA) and persistent type II endoleak. The cohort comprises 210 patients undergoing EVAR between January 2010 and December 2018. A persistent type II endoleak was defined as any type II endoleak lasting longer than six months and included also a type II endoleak diagnosed after six months or more post-EVAR during the 36-month follow-up period confirmed with CT-angiography. Anteroposterior AAA maximum diameter and AAA volume were measured pre-EVAR and 36 months post-EVAR using CT-angiographic pictures. Sac progression was defined as at least 5 mm increase, sac regression as at least 5 mm decrease in the sac diameter in relation to the preprocedural diameter. Sociodemographic information, comorbidities, treatment, laboratory parameters, selected anatomical and genetic factors were all analyzed to determine their impact on persistent type II endoleak. The adjustments included age, hypertension, diabetes mellitus, dyslipidemia, sex, smoking in multivariate analyses. When postprocedural diameter and volume were evaluated, adjustments included also preprocedural diameter/volume. After exclusion, 178 patients with mean age 72.4±7.60 years remained for analysis. Persistent type II endoleak was found in 27.5% of patients (N.=49) and 2.94-times increased risk of sac progression in multivariate analysis (P=0.033). In multivariate analysis, AAA diameter in patients with persistent type II endoleak was 4.31 mm greater than in patients without (B=4.31; P=0.014); and its presence was also associated with 22.0 cm3 greater sac volume (B=22.0; P=0.034) compared to patients without persistent type II endoleak. Treatment with calcium channel blockers increased risk of persistent type II endoleak 2.11-times in multivariate analysis (OR=2.11; 95% CI: 1.05-4.25; P=0.037). No association between persistent type II endoleak and selected polymorphisms associated with AAA and other observed factors were found. Risk of persistent type II endoleak was more than doubled in patients taking calcium channel blockers. Patients with persistent type II endoleak had greater anteroposterior sac diameter and sac volume compared to patients without persistent type II endoleak.

Extent of mural thrombus is not associated with increased 5-year mortality following elective AAA repair.

Mural thrombus in abdominal aortic aneurysm (AAA) has been associated with increased rates of aneurysm growth as well as adverse cardiovascular events. The extent of mural thrombus in thoracoabdominal aortic aneurysms has recently been linked to 1-year mortality following endovascular repair and has been hypothesized as a marker for reduced cardiac reserve. This study investigates whether the extent of mural thrombus in infra-renal AAA is associated with 5-year mortality following elective repair. Retrospective review of all patients undergoing elective infra-renal AAA repair at a single academic medical center between 2007 and 2016 was performed. The following variables at the time of surgery were investigated for association with 5-year mortality: age, sex, ethnicity, insurance status and co-morbidities, repair type, renal insufficiency, end-stage renal disease on dialysis, history of smoking, coronary artery disease, congestive heart failure, diabetes mellitus, hypertension, stroke, chronic obstructive pulmonary disease, body mass index category, AAA diameter, and ratio of aortic thrombus to total aneurysm diameter. Amongst 427 patients undergoing infra-renal AAA repair during the study period, 232 met extensive inclusion criteria. Univariate analysis found mean age (76 vs 72, p < 0.01), age cohort over 72 years (OR = 1.9, p = 0.04), renal insufficiency (OR = 3.1, p < 0.01), ESRD (OR = 6.5, p < 0.01), AAA diameter 6cm or greater (OR = 2.3, p < 0.01), and mean AAA diameter (61.36vs 56.99mm, p < 0.01) all predictive of 5-year mortality. Multivariate analysis revealed renal insufficiency (p < 0.01) and AAA diameter 6cm or greater (p = 0.03) to be significantly associated with 5-year mortality. The extent of mural thrombus was identical between 5-year survivors and non-survivors. The mean inner to outer AAA diameter was 0.65 in the survivor cohort and 0.64 in the mortality cohort. Inner to outer ratio of < 0.5 was identified in 23% of 5-year survivors and 27% of the mortality group. In our experience, the extent of mural thrombus in AAA does not influence long-term survival after elective repair. AAA repair may provide protection against circulating components of mural thrombus which have the potential to promote atherosclerotic-related adverse events. Patients with renal insufficiency and larger AAA have increased risk of mortality 5 years after elective repair.

Endovascular Treatment of Abdominal Aortic Aneurysm With Severe Angulation of Infrarenal Aortic Neck by Gore Conformable Endograft

Introduction: The aim of the study is to report a single-center experience with the Gore Excluder conformable endograft with active control system (CEXC Device, W.L. Gore and Associates, Flagstaff, AZ, USA) in abdominal aortic aneurysms (AAAs) with severe infrarenal neck angulation. Methods: All patients underwent EVAR with CEXC Device between September 2018 and 2020, were prospectively enrolled, and retrospectively analyzed. Anatomical details of the proximal aortic neck were evaluated. Early endpoints were the use of repositionability and angulation system, intraoperative unplanned cuff, technical success (TS), 30-day morbidity/mortality, and reintervention. Follow-up endpoints were type-I endoleaks, endograft migration, aortic neck dilatation, aneurismal sac shrinkage, survival (S), and freedom from reintervention (FFR). Results: Twenty-five patients were enrolled (median age: 80 [range = 60-90] years, median AAA diameter: 60 [range = 52-90] mm). All patients had severe infrarenal neck angulation (beta angle ≧ 60°), and 11 (44%) of those had neck beta angle ≧ 90°. Median infrarenal neck angle, length, and diameter were 70° (range = 60°-90°), 22 (range = 13-42) mm and 22 (range = 18-31) mm, respectively. Endograft repositioning system was employed in 15 (60%) cases and the median number of repositioning maneuvers was 1 (range:0-4). Active angulation system was used in 17 (68%) patients. The median proximal diameter of the main-body and oversize were 28 (range = 23-36) mm and 28% (range = 21%-38%), respectively. Proximal cuff was positioned in 1 (4%) patient. Technical success was achieved in all cases. Intraoperative and perioperative morbidity and mortality were 12% and 0%, respectively. Perioperative type-I/III and II endoleaks were observed in 0 and 4 (16%) patients, respectively. The median follow-up was 12 months (range: 3-30). One patient died at 12-month for AAA-unrelated causes. Abdominal aortic aneurysm-sac shrinkage and stability were observed in 9 (36%) and 15 (60%) cases, respectively. No type-I/III endoleak and reintervention occurred during the follow-up. One persistent type-II endoleak was observed. Estimated survival at 24 months was 92%. Conclusion: According to the present data, the CEXC Device allows an excellent rate of TS in severe angulated aortic neck. This preliminary data, could increase the rate of patients eligible for EVAR.

Post-operative Surveillance and Long Term Outcome after Endovascular Aortic Aneurysm Repair in Patients with an Initial Post-operative Computed Tomography Angiogram Without Abnormalities: the Multicentre Retrospective ODYSSEUS Study

Lifelong imaging surveillance is recommended following endovascular aneurysm repair (EVAR). This study aimed to examine the association between adherence to post-operative surveillance and survival and secondary interventions in patients with an initial post-operative computed tomography angiogram (CTA) without abnormalities. All consecutive patients undergoing EVAR for intact abdominal aortic aneurysm (AAA) in 16 hospitals between 2007 and 2012 were identified retrospectively, with follow up until December 2018. Patients were included if the initial post-operative CTA showed no types I – III endoleak, kinking, infection, or limb occlusion. Discontinued follow up was defined as at least one 16 month period in which no imaging surveillance was performed. Primary outcomes were aneurysm related mortality and secondary interventions, and secondary outcome all cause mortality. Kaplan–Meier analysis was used to estimate survival, and Cox regression analyses to identify the association between independent variables and outcome. Sensitivity analyses were performed by varying the definition of continued yearly follow up. The study protocol was published (bmjopen-2019-033584). 1 596 patients (552 continued, 1 044 discontinued follow up) were included with a median (interquartile range) follow up of 89.1 months (52.6). Cumulative aneurysm related, overall, and intervention free survival was 99.4/94.8/96.1%, 98.5/72.9/85.9%, and 96.3/45.4/71.1% at 1, 5, and 10 years, respectively. American Society of Anesthesiologists (ASA) classification (ASA IV hazard ratio [HR] 3.810, 95% confidence interval [CI] 1.296 – 11.198), increase in AAA diameter (HR 3.299, 95% CI 1.408 – 7.729), and continued follow up (HR 3.611, 95% CI 1.780 – 7.323) were independently associated with aneurysm related mortality. The same variables and age (HR 1.063 per year, 95% CI 1.052 – 1.074) were significantly associated with all cause mortality. No difference in secondary interventions was observed between patients with continued vs. discontinued follow up (89/552; 16% vs. 136/1044; 13%; p = .091). Sensitivity analyses showed worse aneurysm related and overall survival in patients with continued follow up. Discontinued follow up is not associated with poor outcomes. Future prospective studies are indicated to determine in which patients imaging follow up can be safely reduced.

Athero-occlusive Disease Appears to be Associated with Slower Abdominal Aortic Aneurysm Growth: An Exploratory Analysis of the TEDY Trial

The role of atherosclerosis in abdominal aortic aneurysm (AAA) pathogenesis is controversial. The aim of this study was to compare AAA growth in patients who did and did not have concurrent athero-occlusive disease (AOD). Patients with an AAA measuring 35 - 49 mm in maximum diameter were recruited as part of the TElmisartan in the management of abdominal aortic aneurysm (TEDY) trial. TEDY participants who had infrarenal aortic volume and orthogonal diameter assessed by computed tomography at entry and at least one other time point during the trial (12 and/or 24 months) were included. AOD was defined by prior diagnoses of coronary heart disease, stroke, or peripheral arterial disease or an ankle brachial pressure index < 0.90. The increase in AAA volume and diameter from entry for participants who did and did not have AOD was assessed using linear mixed effects models; 131 of the 210 participants recruited to TEDY were included. In an unadjusted analysis, the mean (95% confidence interval) annual increases in AAA volume and diameter for participants with AOD were 3.26 (0.82 - 5.70) cm3 and 0.70 (0.19 - 1.22) mm slower than those without AOD, p= .008 and .007 respectively. The association between AOD and significantly slower AAA growth was maintained after adjusting for risk factors and medications, significantly unequally distributed between participants with and without an AOD diagnosis. In an exploratory analysis of a selective cohort from the TEDY trial, AOD was associated with slower AAA growth. Validation of these findings in other cohorts is needed.

Fenestrated endovascular aortic aneurysm repair promotes positive infrarenal neck remodeling and greater sac shrinkage compared with endovascular aortic aneurysm repair

ObjectiveEndovascular aortic aneurysm repair (EVAR) has become the standard of care for abdominal aortic aneurysms (AAAs) in the modern era. Although numerous devices exist for standard infrarenal AAA repair, fenestrated EVAR (fEVAR) offers a minimally invasive alternative to traditional open repair for patients with a short infrarenal neck. Over time, aortic neck dilation can occur, leading to loss of the proximal seal, endoleaks, and AAA sac growth. In the present study, we analyzed aortic remodeling after EVAR vs fEVAR and further evaluated whether fEVAR confers a benefit in terms of sac shrinkage. MethodsA retrospective review of prospectively collected data from 120 patients who had undergone EVAR was performed. Of these 120 patients, 30 had been treated with fEVAR (Zenith fenestrated; Cook Medical Inc, Bloomington, IN) and 90 patients were treated with EVAR devices (30 each with Endurant [Medtronic, Dublin, Ireland], Excluder [W.L. Gore & Associates, Flagstaff, AZ], and Zenith [Cook Medical Inc]). The demographic data were recorded. Also, anatomic measurements were performed for each patient preoperatively, at 30 days postoperatively, and at the longest follow-up point using three-dimensional reconstruction software. ResultsNo significant differences were found in demographic data between the four groups. fEVAR had been used more often in aortas with large necks and irregular morphology (P = .004). At the longest follow-up, the suprarenal aorta encompassing 5, 10, and 15 mm above the lowest renal artery had dilated the most for the fEVAR group vs all EVAR groups. However, the infrarenal segment had tended to increase the least, or to even have regressed, for fEVAR compared with all three EVAR groups and was associated with the overall greatest proportion of sac shrinkage for the fEVAR group compared with the Medtronic, Gore, and Cook devices (−13.90% vs −5.75% vs −2.31% vs −4.68%, respectively; P = .025). ConclusionsCompared with EVAR, the patients treated with fEVAR had experienced greater suprarenal dilation over time, consistent with an overall greater burden of disease in the proximal native aorta. However, the infrarenal segment had dilated significantly less over time in the fEVAR group compared with all three EVAR groups, suggesting that fEVAR might stabilize the infrarenal neck, promoting positive sac remodeling, which was evidenced by the greatest degree of decrease in the largest AAA diameter in the fEVAR group.

Persisting Type 2 Endoleaks Following EVAR for AAA Are Associated With AAA Expansion

Purpose: To determine the evolution of abdominal aortic aneurysm (AAA) diameter in the presence of persisting type 2 endoleaks (pEL2) following endovascular abdominal aortic aneurysm repair (EVAR). Materials and Methods: This is a retrospective, single-center, case-control study. All patients with pEL2 (pEL2 group, persisting for > 12 months) between 2004 and 2018 were identified and compared with a 1:1 age- and gender-matched control with no endoleak (control group). Primary outcome measures were freedom from AAA expansion and freedom from AAA shrinkage over time. AAA diameter measurements were performed on computed tomography angiography (CTA). Secondary outcome measures were survival, AAA-related mortality, reinterventions for pEL2, incidence of secondary type 1 endoleaks (EL1), and infrarenal aortic branch vessel anatomy. Results: A total of 773 patients were treated with EVAR for AAA between 2004 and 2018. Of them, 286 patients demonstrated type 2 endoleaks (EL2) in postoperative CTA or intraoperative angiography (37%). Forty-five of 286 EL2 (15.7%) were pEL2 (pEL2 group). Freedom from AAA expansion in the pEL2 group was 100%, 96.7%, 85.2%, and 54.3% after 1, 2, 3, and 4 years, respectively, compared with 100% after 1, 2, 3, and 4 years in the control group (p<0.01). Freedom from AAA shrinkage in the pEL2 group after 1, 2, 3, and 4 years was 95.5%, 90.4%, 90.4%, and 79.1%, respectively, compared with 86.7%, 34.8%, 19.3%, and 19.3% in the control group (p<0.01). Overall survival at 1, 2, 3, and 4 years was 100%, 97.6%, 95.0% and 95.0% in the pEL2 group and 100% at 1, 2, 3, and 4 years in the control group (p=0.17). There were no AAA-related deaths in either group. Patients with pEL2 had a significantly increased number of infrarenal aortic branches (p<0.05, respectively). Eighteen patients (40.0%) in the pEL2 group underwent 34 reinterventions for pEL2, with a median follow-up (FU) of 925 days (0–4173). Clinical success was achieved in 9 patients (50.0%). Four patients (8.9%) with pEL2 developed secondary EL1 after a median FU of 1278 days (662–2121). Conclusion: pEL2 are associated with AAA expansion during midterm FU. Further studies are warranted to evaluate the association of AAA expansion due to pEL2 with clinical outcomes to allow recommendations with regard to treatment indications.

Predictors of Abdominal Aortic Aneurysm Shrinkage after Endovascular Repair.

Recent studies demonstrate that patients with a shrinking abdominal aortic aneurysm (AAA), one-year after endovascular repair (EVAR), have better long-term outcomes than patients with a stable AAA. It is not known what factors determine whether an AAA will shrink or not. In this study, a range of parameters was investigated to identify their use in differentiating patients that will develop a shrinking AAA from those with a stable AAA one-year after EVAR. Hundred-seventy-four patients (67 shrinking AAA, 107 stable AAA) who underwent elective, infrarenal EVAR were enrolled between 2011–2018. Long-term survival was significantly better in patients with a shrinking AAA, compared to those with a stable AAA (p = 0.038). Larger preoperative maximum AAA diameter was associated with an increased likelihood of developing AAA shrinkage one-year after EVAR—whereas older age and larger preoperative infrarenal β angle were associated with a reduced likelihood of AAA shrinkage. However, this multivariate logistic regression model was only able to correctly identify 66.7% of patients with AAA shrinkage from the total cohort. This is not sufficient for implementation in clinical care, and therefore future research is recommended to dive deeper into AAA anatomy, and explore potential predictors using artificial intelligence and radiomics.

Arterial stiffness and central aortic blood pressure in patients with hypertension and abdominal aortic aneurysm

Objective. To assess the arterial stiffness, peripheral and central aortic blood pressure (PBP and CBP), and to determinate their relationships with indicators of structural changes of the affected aorta in patients with hypertension (HTN) and abdominal aortic aneurysms (AAA).Design and methods. We examined 75 patients with HTN and AAA and 75 controls with HTN without AAA. Groups matched by age and gender. A PBP was measured by OMRON (Japan). Noninvasive measurements of CBP, augmentation index (AIx), augmentation pressure (AP), carotid-femoral pulse wave velocity (cfPWV) were assessed by SphygmoCor (AtCorMedical, Australia).Results. There was no difference in cfPWV between patients with AAA and control group (10,3 (2,2) vs 9,7 (2,1) m/s; р = 0,102). Age, systolic PBP, and aortic diameter were independent predictors of cfPVV in patients with AAA (β = 0,271, р = 0,029; β = 0,272, р = 0,030 и β = –0,361, р = 0,004, respectively). Patients with large aortic diameter of AAA (&gt; 60 mm) had decreased cfPWV compared with control group (8,8 (1,5) vs 9,7 (2,1) m/s; р &lt; 0,05), patients with AAA diameter less than 60 mm, on the contrary, had increased cfPVV compared with the controls (11,8 (1,7) vs 9,7 (2,1) m/s; р &lt; 0,001). Patients with AAA and patients of control group did not differ in systolic and pulse PBP (138,6 (16,4) vs 138,1 (13,6) mm Hg; р = 0,831 and 58,6 (11,8) vs 59,6 (10,2) mm Hg; р = 0,569, respectively). AIx and AP were higher in patients with AAA versus patients without AAA (27,6 (8,2) vs 21,3 (7,9)%; р &lt; 0,001 and 17,3 (6,8) vs 13,9 (5,4) mm Hg; р = 0,001, respectively). Systolic and pulse CBP were higher in patients with AAA than in patients of control group (130,0 (16,4) vs 124,9 (13,9) mm Hg; р = 0,046 and 49,5 (11,7) vs 45,7 (9,9) mm Hg; р = 0,031, respectively).Conclusions. In patients with AAA cfPWV decreased with the expansion of the maximum aortic diameter. CfPWV is not suitable for accurate arterial stiffness assessment in patients with HTN and AAA due to the apparent confounding effect of aneurysm on the biomechanical properties of the aorta. Local assessment of the elastic properties of the aorta such as computed tomography angiography and magnetic resonance imaging is required for arterial stiffness evaluation in patients with AAA. Parameters of the reflected pulse wave such as AP and AIx are increased in patients with AAA. This might contribute to the increase in central aortic BP and target organ damage in patients with HTN combined with AAA.

Long-term outcomes of endovascular aortic repair with flared iliac limb endografts in patients with abdominal aortic aneurysm and aneurysmal common iliac arteries.

The aim of this study was to evaluate the long-term outcomes of endovascular aneurysm repair with flared iliac limb grafts in patients with abdominal aortic aneurysm (AAA) and aneurysmal common iliac arteries (CIAs). This is a multicenter, retrospective, observational cohort study that involves four tertiary referral hospitals between May 1, 2005, and April 30, 2019. Primary outcomes were freedom from aneurysm-related mortality (ARM), and freedom from iliac-related reintervention. We studied 995 aneurysmal iliac limbs in 795 (85.2%) patients who met the inclusion criteria. Median AAA diameter was 55mm (IQR: 51-60). Early mortality occurred in 3 (0.4%) patients. The median of follow-up time was 52 months (IQR: 26-88). Estimated freedom from ARM was 99±0.002% (95% CI: 99-99.9) at 1 year, and 99±0.004% (95% CI: 97.9-99.6) at 5-years. Chronic obstructive pulmonary disease (HR=6.4, 95% CI: 1.7-24.0, P=0.006), chronic kidney disease (HR=5.5, 95% CI: 1.4-21.9, P=0.016), and the presence of an aneurysmal left CIA (HR=5.3, 95% CI: 1.0.5-27.4, P=0.044) was associated with ARM. There were 42 (7.3%) late iliac-related events (limb occlusion, N.=5; iliac-related endoleaks, N.=37). Estimated freedom from iliac-related reintervention was 98±0.003% (95% CI: 97-99) at 1 year, and 95±0.01% (95% CI: 92.7-96.7) at 5-years, which was associated with an aneurysmal right CIA (HR=2.2, 95% CI: 1.3-3.9; P=0.005), and age ≥78 years (HR=1.9, 95% CI: 1.01-1.3; P=0.039). EVAR flared iliac limb grafts showed a high rate of freedom from ARM and a low reintervention rate. Owing to these results, it can be a durable and stable alternative for patients aged >78 years.