Abdominal Aortic Aneurysm Diameter Research Articles

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.

Understanding who benefits from endovascular aortic repair in those deemed unfit for open repair

IntroductionPatients with abdominal aortic aneurysms (AAAs) who are deemed unacceptable candidates for open repair (UNFIT) pose a clinical challenge. The EVAR2 Trial randomized UNFIT patients to endovascular aortic repair (EVAR) vs no intervention from 1999 to 2003, concluding that survival was not improved by EVAR. However, outcomes after EVAR over the last 2 decades have dramatically changed. Thus, the purpose of this study was to evaluate outcomes after EVAR in UNFIT patients using more contemporary data and to determine which subsets of UNFIT patients may potentially benefit from EVAR. MethodsThe Vascular Quality Initiative database (2003-2020) was used to identify elective EVARs for AAAs. Patients were categorized as UNFIT or suitable (SUITABLE) for open repair by the operative surgeon. Predicted 1-year mortality of untreated AAAs was calculated via a modified Gagne Index adjusted for AAA size. The primary outcome for the study was 30-day mortality. Secondary outcomes included perioperative major adverse cardiac events (a composite of clinically significant arrhythmia, congestive heart failure, and myocardial infarction), length of stay, and 1-year mortality. ResultsA total of 31,471 patients met study criteria with 27,036 (85.9%) deemed SUITABLE and 4435 (14.1%) UNFIT. UNFIT patients were more likely to experience a perioperative major adverse cardiac event (5.1% vs 2.2%, P < .001) and had longer lengths of stay (1 day [interquartile range, 1-3 days] vs 1 day [interquartile range, 1-2 days], P < .001). The 30-day mortality was significantly higher for UNFIT patients (0.8% vs 0.4%, P < .001). UNFIT patients had worse 1-year survival compared with SUITABLE patients. However, UNFIT and SUITABLE patients had significantly improved actual 1-year mortality with EVAR compared with predicted 1-year mortality without EVAR: 9.5% vs 15.6% (P < .001) and 4.0% vs 11.7% (P < .001), respectively. The mortality benefit after EVAR in UNFIT patients was primarily restricted to those with smaller Gagne Indices and larger aneurysm diameters. Patients deemed unsuitable for open repair due to frailty or multiple reasons had significantly higher 30-day mortality rates after EVAR when compared with SUITABLE patients (1.3% vs 1.6% vs 0.4%, P < .001). Those deemed unsuitable for open repair due to frailty or multiple reasons had worse 1-year cumulative survival compared with all other UNFIT patients. ConclusionsDespite being high risk with higher perioperative morbidity and mortality, UNFIT patients have lower actual 1-year mortality with EVAR than predicted 1-year mortality without EVAR. However, this potential benefit is reserved to those with small Gagne Indices, larger AAA diameters, and lack of frailty.

Alterations in gut microbiota and physiological factors associated with abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a progressive focal dilatation and weakening of the abdominal aorta, causing 1.3% of all deaths among men aged 65–85 years worldwide. The formation of AAA is a complex process with multiple risk factors. Therefore, this study aimed to determine the relationship of disease severity and physiological factors, and gut microbiota structures in AAA patients. Physiological indicators and fecal 16S rRNA gene sequences from healthy controls and patients with AAA were collected. The correlations between the diameter of the AAA and clinical parameters, and gut microbiota composition were then analyzed separately using multivariable analysis. The diameter of AAA was extremely positively correlated with smoking index, alkaline phosphatase, blood glucose, and blood triglycerides and negatively correlated with prealbumin and Cystatin C. As the diameter of AAA increased, the α-diversity, including Chao 1, Shannon, and Simpson indices, of the gut microbiota decreased and presented a negative linear relationship. Patients with AAA with more severe disease had significantly increased relative abundance of Enterobacteriaceae and decreased relative abundance of Veillonellaceae. A strong correlation was observed between the diameter and physiological data, as well as between diameter and gut microbiota composition. This study could improve the understanding of AAA, and gut microbiota may be a potential target to prevent and treat this deadly disease.

Editor's Choice – 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.

The expression and role of tenascin C in abdominal aortic aneurysm formation and progression.

OBJECTIVESUp-regulation of tenascin C (TNC), a matricellular protein, produced mainly by vascular smooth muscle cells (VSMC), is associated with the progression and dilation of abdominal aortic aneurysms (AAA). The aims of this study were (i) to evaluate whether serum levels of TNC in patients with AAA patients correlate with aortic diameter and (ii) to clarify the role of TNC in formation and progression of AAA in a murine model.METHODSIn 15 patients with AAA serum levels of TNC were measured and correlated with aortic diameters. Moreover, in a murine calcium chloride AAA model, the impact of TNC deficiency on AAA diameter was evaluated. Finally, human VSMC were incubated with TNC to clarify its regulating potential.RESULTSIn the clinical cohort, there was a trend of correlation between serum TNC levels and AAA diameter (P = 0.055). TNC knock out mice with AAA showed significantly lower diameter ratios compared to the wild-type group (WT) 3 weeks (P < 0.05) and 10 weeks (P < 0.05) after AAA induction. Immunohistochemistry revealed increased TNC expression in aortic tissue from WT with AAA as compared sham-operated mice. Furthermore, WT with AAA showed a more disrupted Elastin structure than TNC knock out mice 10 weeks after AAA induction. In human aortic VSMC, TNC incubation induced expression of remodelling associated proteins.CONCLUSIONSTNC might play a causative role in the formation, dilation and progression of AAA. Our results indicate that TNC might be a biomarker as well as a potential therapeutic target in the treatment of AAA.

Eugenol restrains abdominal aortic aneurysm progression with down-regulations on NF-κB and COX-2.

Abdominal aortic aneurysm (AAA) is a lethal disease without available medicine for treatment. This study aimed to evaluate the efficiency of eugenol (4-allyl-2-methoxyphenol) against AAA and the underlying mechanism. Eugenol is the major bioactive component of clove. A mouse AAA model was established through porcine pancreatic elastase (PPE) incubation peri-adventitially and 1% 3-aminopropanonitrile (BAPN) diet. Continuous AAA progression from day 0 to day 15 was observed after PPE plus BAPN treatment, according to the AAA diameter and histopathological evaluation. Accompanying with AAA progression, sustained increased expressions of CD68, COX-2 and NF-κB were observed through immunofluorescence assay. After elucidation the efficiency of eugenol against AAA progression by AAA diameter, hematoxylin-eosin staining and orcein staining, the down-regulations of eugenol on COX-2 and NF-κB were further detected by immunohistochemistry and western blot. Eugenol not only blocked AAA expansion and protected the integrity of aortic structure in a dose-dependent manner, but also held high oral bioavailability. Excellent efficiency, high oral bioavailability and down-regulation on COX-2/NF-κB endowed eugenol great potential for future AAA therapy.

Abdominal Aortic Aneurysm Rupture Risk Assessment Using Machine Learning to Integrate Biomechanical, Geometrical, and Patient Characteristics

Introduction: The correlation between maximum diameter and rupture in abdominal aortic aneurysm (AAA) has been studied extensively, and a maximum AAA diameter of 55 mm in men or a diameter growth of more than 10 mm per year are accepted to indicate AAA repair. However, the maximum diameter criterion fails to describe AAA rupture risk in a patient specific manner and should therefore not directly be applied to individual patients. The poor sensitivity of diameter has been known for a long time and has stimulated the search for more patient specific risk indicators.