AAA Diameter Research Articles

Long-term outcomes after repair of symptomatic abdominal aortic aneurysms

ObjectivesPrevious studies have reported increased perioperative mortality of nonruptured symptomatic abdominal aortic aneurysms (Sx-AAA) compared with asymptomatic elective AAA (E-AAA) repairs, but no long-term-outcomes have been reported. We sought to compare long-term outcomes of Sx-AAA and E-AAA after repair at a single academic institution. MethodsPatients receiving AAA repair for Sx-AAA and E-AAA from 1995 through 2015 were included. Ruptured AAA and suprarenal or thoracoabdominal AAA were excluded. Demographics, comorbidities, and operative approach were collected. Long-term mortality was the primary outcome, determined by chart review or link to Social Security Death Index. Additionally, long-term mortality and reinterventions were compared after groups were matched with nearest neighbor propensity to reduce bias. ResultsAAA repair was performed for 1054 E-AAA (383 open repair [36%], 671 endovascular aneurysm repair [EVAR] [64%]), and 139 symptomatic aneurysms (60 open repair [43%], 79 EVAR [57%]). Age (73 years vs 74 years; P = .13) and aneurysm diameter were similar between Sx-AAA and E-AAA (6.0 cm vs 5.8 cm; P = .5). The proportion of women was higher for Sx-AAA (26% vs 16%; P = .003), as was the proportion of non-Caucasians (40% vs 29%; P = .009). After propensity matching, there were no differences between groups for patient characteristics, AAA diameter, treatment modality, or comorbidities, including hypertension, coronary artery disease, congestive heart failure, diabetes, hyperlipidemia, lung disease, diabetes, renal disease, and smoking history. Women were treated for Sx-AAA at significantly smaller aortic diameters; however, compared with men (5.1 cm vs 6.3 cm; P < .001). Perioperative mortality was 5.0% for Sx-AAA and 2.3% for E-AAA (P = .055). By life-table analysis, Sx-AAA had lower 5-year (62% vs 71%) and 10-year (39% vs 51%) survivals (P = .01) compared with E-AAA for the entire cohort. Similar trends were observed for 5-year and 10-year mortality after propensity matching (63% and 40% vs 71% and 52%; P = .05). When stratified by repair type 5-year and 10-year survivals trended lower after open surgery (68% and 42% Sx-AAA vs 84% and 59% E-AAA; P = .08) but not EVAR (59% and 40% Sx-AAA vs 61% and 49% E-AAA; P = .4). Aneurysm-related reinterventions were similar for Sx-AAA and E-AAA (15% vs 14%; P = .8). Reinterventions were more common after EVAR compared with open repair (22% vs 7%, Sx-AAA P = .015; 20% vs 4% E-AAA; P = .007). ConclusionsPatients with Sx-AAA had lower long-term survival and similar aneurysm-related reinterventions compared with patients with E-AAA undergoing repair. Women also underwent repair for Sx-AAA at a significantly smaller size when compared with men, which emphasizes the role of gender in AAA symptomatology. Differences in long-term survival may be only partially explained by measured patient, aneurysm, and operative factors, and may reflect unmeasured social factors or suggest inherent differences in pathophysiology of Sx-AAAs.

Editor's Choice – The Impact of Centralisation and Endovascular Aneurysm Repair on Treatment of Ruptured Abdominal Aortic Aneurysms Based on International Registries

Current management of ruptured abdominal aortic aneurysms (RAAA) varies among centres and countries, particularly in the degree of implementation of endovascular aneurysm repair (EVAR) and levels of vascular surgery centralisation. This study assesses these variations and the impact they have on outcomes. RAAA repairs from vascular surgical registries in 11 countries, 2010-2013, were investigated. Data were analysed overall, per country, per treatment modality (EVAR or open aortic repair [OAR]), centre volume (quintiles IV), and whether centres were predominantly EVAR (≥50% of RAAA performed with EVAR [EVAR(p)]) or predominantly OAR [OAR(p)]. Primary outcome was peri-operative mortality. Data are presented as either mean values or percentages with 95% CI within parentheses, and compared with chi-square tests, as well as with adjusted OR. There were 9273 patients included. Mean age was 74.7 (74.5-74.9) years, and 82.7% of patients were men (81.9-83.6). Mean AAA diameter at rupture was 7.6cm (7.5-7.6). Of these aneurysms, 10.7% (10.0-11.4) were less than 5.5cm. EVAR was performed in 23.1% (22.3-24.0). There were 6817 procedures performed in OAR(p) centres and 1217 performed in EVAR(p) centres. Overall peri-operative mortality was 28.8% (27.9-29.8). Peri-operative mortality for OAR was 32.1% (31.0-33.2) and for EVAR 17.9% (16.3-19.6), p<.001, and theadjusted OR was 0.38 (0.31-0.47), p<.001. The peri-operative mortality was 23.0% in EVAR(p) centres (20.6-25.4), 29.7% in OAR(p) centres (28.6-30.8), p<.001; adjusted OR=0.60 (0.46-0.78), p<.001. Peri-operative mortality was lower in the highest volume centres (QI>22 repairs per year), 23.3% (21.2-25.4) than in QII-V, 30.0% (28.9-31.1), p<.001. Peri-operative mortality after OAR was lower in high volume centres compared with the other centres, 25.3% (23.0-27.6) and 34.0% (32.7-35.4), respectively, p<.001. There was no significant difference in peri-operative mortality after EVAR between centres based on volume. Peri-operative mortality is lower in centres with a primary EVAR approach or with high case volume. Most repairs, however, are still performed in low volume centres and in centres with a primary OAR strategy. Reorganisation of acute vascular surgical services may improve outcomes of RAAA repair.

Evolution of Computed Tomography Imaging the First Year after Endovascular Sealing of Infrarenal Aortic Aneurysms Using the Nellix Device

The Nellix endovascular aneurysm sealing (EVAS) system is an alternative endovascular treatment option for infrarenal aortic aneurysms (AAAs), with a unique appearance on computed tomography angiography (CTA). Normal evolution of post-EVAS CTA appearance follow-up is still largely unknown and important to timely detect eventual complications. The objective is to assess the normal appearance of CTA images 30days and 1year after EVAS in 50 consecutive patients. Fifty patients treated with Nellix EVAS for an infrarenal AAA were included from 3 hospitals. Using dedicated software, a total of 150 CTA scans were analyzed by predetermined variables per anatomical segment. Thirty days post-EVAS, there was a slight, but not statistically significant, increase in AAA diameter that returned to the preoperative value after 1 year. A shift in total aortic volume distribution was observed without changing aortic diameter, including a trend toward a decreased thrombus volume (85.6±49.1mL and 78.8±35.5mL at 30days and 1 year, respectively, P<0.242) and a slight, but statistically significant, increase in polymer volume (68.2±34.1mL and 71.9±35.2mL at 30days and 1 year, respectively, P<0.001). The β-angle (P=0.06) and iliac artery angulation (P<0.001) decreased after implant. The latter returned to its original state after 1 year, whereas the neck straightening remained. Over time, there was a significant decrease in radiodensity in the middle of the polymer-filled endobags with an increase at its edges (P<0.05). Thrombus radiodensity significantly increased over the first year (P<0.05). Diameters of the infrarenal neck and common iliac arteries remained unchanged, no endoleaks were observed, and the position of the device was stable. Change of CT appearance after EVAS is unique, and as such, the judgment of these images requires experience. The appearance of the endobags in respect to volume and radiodensity differ from classic EVAR. Normal changes over time are observed in aortoiliac angulation, volumes, and radiodensities.

Elastic reconstruction of shear modulus and stress distribution for assessing abdominal aorta aneurysmal rupture risk

The necessity of surgical intervention of abdominal aorta aneurysms is based on a risk-reduction paradigm primarily relying on trans-abdominal ultrasound (US) measurements of the maximum diameter of an AAA. However, AAA diameter is only a rough estimate of rupture potential and elastographic estimates of material property changes and stresses within aortic tissue may be a better predictor. This work presents an elastic imaging technique to match model predicted displacement fields to those measured using clinical US. A linear elastic finite-element model is used and is assumed to be undergoing a quasi-static, plane strain deformation. This technique uses a regularization scheme to incorporate geometric segmentation information, as a penalty or soft prior, to counter the inherent ill-posedness of the inverse problem. In addition, displacement fields are measured and accumulated over the entire cardiac cycle and incorporated simultaneously in the reconstruction technique to improve the signal to noise of the recovered modulus distribution. Model predicted strain fields and modulus distributions are used to predict the relative stress induced over the cardiac cycle. Results of validation studies comparing modulus and stress fields performed using finite-element simulations of 3D and time dependent geometries, tissue-mimicking phantom simulations, and initial clinical results will be presented.

Iliac Seal Zone Dynamics and Clinical Consequences After Endovascular Aneurysm Repair

To evaluate the dynamics of the iliac attachment zone after EVAR, and the association with clinical events. A tertiary institution's prospective EVAR database was searched to identify common iliac arteries at risk. Internally validated measurements were made, using centre lumen line reconstructions. Iliac dilatation and endograft limb retraction were the main endpoints. Associations between dilatation, retraction, oversizing, and distal seal length were investigated. Association with clinical events (sealing or occlusion) was also explored. Of 452 primary EVAR patients treated from 2004 to 2012, 341 were included (mean age 72 years, 12% female, 597 common iliac arteries). Median follow-up was 4.7 years. At 30 days, the mean iliac diameter increased from 14mm to 15mm (p<.001). Over follow-up, it increased to 18mm (p<.001). Iliac dilatation ≥20% occurred in 295 cases (49.4%) and exceeded the implanted endograft diameter in 170 (28.7%). Limb retraction ≥5mm was identified in 54 patients (9.1%) and was associated with iliac seal complications (p<0.001). Iliac endograft extension diameter ≥24mm (OR 3.3, 95% CI 1.7-6.4) and iliac artery dilatation beyond the endograft (OR 2.1, 95% CI 1.2-3.8) were independent risk factors. Overall, there were 34 (5.7%) iliac seal complications. Retraction of the iliac endograft (OR 1.17 per mm, 95% CI 1.10-1.24) and baseline AAA diameter (1.04 per mm, 95% CI 1.01-1.07) were independent risk factors for seal related complications. Greater initial post-operative iliac seal length was protective (OR 0.94 per mm, 95% CI 0.90-0.97). Iliac dilatation and endograft retraction are common findings during follow-up, potentially leading to adverse clinical events. Optimisation of the iliac seal zone providing a long distal seal length and added attention to patients with large aneurysms or receiving ≥24mm diameter iliac extensions are recommended. Also, long-term surveillance including CTA is advised to reveal and correct loss of seal at the iliac attachments before adverse clinical events occur.

Heterogeneous histomorphology, yet homogeneous vascular smooth muscle cell dedifferentiation, characterize human aneurysm disease

ObjectiveAbdominal aortic aneurysm (AAA) is a frequent, potentially life-threatening, disease that can only be treated by surgical means such as open surgery or endovascular repair. No alternative treatment is currently available, and despite expanding knowledge about the pathomechanism, clinical trials on medical aneurysm abrogation have led to inconclusive results. The heterogeneity of human AAA based on histologic examination is thereby generally neglected. In this study we aimed to further elucidate the role of these differences in aneurysm disease. MethodsTissue samples from AAA and popliteal artery aneurysm patients were examined by histomorphologic analysis, immunohistochemistry, Western blot, and polymerase chain reaction. The results were correlated with clinical data such as aneurysm diameter and laboratory results. ResultsThe morphology of human AAA vessel wall probes varies tremendously based on the grade of inflammation. This correlates with increasing intima/media thickness and upregulation of the vascular endothelial growth factor cascade but not with any clinical parameter or the aneurysm diameter. The phenotypic switch of vascular smooth muscle cells occurred regardless of the inflammatory state and expressional changes of the transcription factors Kruppel-like factor-4 and transforming growth factor-β lead to differential protein localization in aneurysmal compared with control arteries. These changes were in similar manner also observed in samples from popliteal artery aneurysms, which, however, showed a more homogenous phenotype. ConclusionsHeterogeneity of AAA vessel walls based on inflammatory morphology does not correlate with AAA diameter yet harbors specific implications for basic research and possible aneurysm detection.

Degradation Phenomena on Second Generation of Explanted Aortic Textile Endografts

s 403 3 Department of Vascular and Endovascular Surgery, Manchester Royal Infirmary, United Kingdom Department of Vascular and Endovascular Surgery, University Hospital South Manchester, Manchester, United Kingdom Introduction: We previously reported our early experience using the firstgeneration multi-layer flow modulating stent (MFMS) for patients with thoraco-abdominal (TAAA) and perirenal aneurysms (PAA) who were unsuitable for conventional EVAR and unfit for open repair. We encountered continued aneurysm growth, device component dislocation and re-intervention. Our study patients have now completed at least 3 years follow-up and we report the outcomes. Methods: Patients with TAAA and PAA unfit for open surgery and with no conventional options for endovascular repair were recruited by two UK vascular units. Follow-up included CTA at 1, 3, 6, and 12 months, then annually until 3 years. Outcome measures included 30 day mortality, growth-free survival, branch vessel patency, complications, re-intervention and maximal aortic diameter. Results: MFMS were implanted in 14 patients (6 PAA, 8 TAAA) between October 2011 and March 2014 with one (7%) 30 day death and 11 (79%) surviving to 12 months. The median aneurysm growth was 9 mm in the first 12 months following implantation. At current follow-up to death or at least 3 years, eleven patients (79%) have died including four confirmed ruptures, one presumed rupture, one confirmed dissection with rupture, one MI post-op (procedure related), one multi-organ failure following re-intervention (procedure related) one myocardial infarction (MI) (out of hospital e unrelated), one pneumonia (not device or procedure related), and one decompensated liver failure (unrelated). Continued aneurysm growth occurred in all patients who suffered rupture or dissection. AAA diameter remains stable in two of the three surviving patients. Fifty of 51 covered aortic branches remained patent with no embolic episodes or symptoms of ischaemia in any patient. MFMS dislocation occurred in four patients, leading to re-intervention in two. A total of six re-interventions were performed in five patients (35%) with one post re-intervention death. Conclusion: These first-generation MFMS were unstable and dislocated frequently. It is uncertain whether MFMS implantation influenced the natural history of these aneurysms as none decreased in size, but two remain stable after a mean of 42.5 months. Although side branch patency was maintained, rupture or dissection occurred in 43% of patients and our results do not support the continued use of these first-generation devices. Further development is needed as this technology has potential as demonstrated by the control of aneurysm rupture in three and growth in two patients. Disclosure of Interest: None Declared. SESSION 4 e MISCELLANEOUS (1) THU, 29 SEPT, 8:00e9:00

PC048. Contemporary Management of Isolated Chronic Infrarenal Abdominal Aortic Dissections

This study reports the presentation, treatment, and follow-up of isolated infrarenal aortic dissections. A review of 37 patients with isolated infrarenal aortic dissections was performed. Computed tomography scans with intravenous contrast were examined for all patients, and catheter-based angiograms, magnetic resonance angiograms, and duplex ultrasound were used selectively. In dissections associated with the development of abdominal aortic aneurysm, the aneurysm growth rate was determined by measuring the change in maximum aneurysm diameter over time and dividing that by the duration of observation. The majority of infrarenal abdominal aortic dissection patients were male (67.6%). Hypertension (77.1%) and hyperlipidemia (77.1%) were the most common comorbidities among these patients. Aortic atherosclerosis was also present in 60.0% of patients. A total of 67.6% of dissections were discovered incidentally and were asymptomatic. The mean dissection length was 5.84 ± 4.23 cm. Concomitant abdominal aortic aneurysms were present in 48.6% of cases with an average maximum diameter of 4.38 ± 1.41 cm. The aneurysm growth rate was 1.2 mm/y. Aneurysms were significantly larger in men than in women (4.87 ± 1.31 vs 3.12 ± 0.67 cm; P = .001). Endovascular intervention was performed on 14 patients (37.8%), open surgery was performed on 1 patient (2.7%), and surveillance with conservative medical treatment was used on 22 patients (59.5%). Ten patients were treated successfully with endovascular repair (EVAR) for progressive aneurysm expansion. At the time of intervention, the mean AAA diameter was 5.04 ± 1.39 cm. The mean growth rate for aneurysms that were intervened on was 2.3 mm/y. The mean diameter of AAA that were not intervened on was 3.56 ± 1.04 cm. Type II endoleaks were observed in 3 patients(30%) who underwent EVAR. None of these were associated with aneurysm growth, and none required reintervention. The mortality rate for endovascular intervention was 0%. The only open surgical repair preformed was on a patient with a ruptured abdominal aortic aneurysm, which the patient did not survive. Angioplasty with stent or stent graft placement was performed in 4 patients for the treatment of symptomatic arterial insufficiency resulting from aortic dissection. No patients experienced restenosis and no reinterventions were performed. Isolated infrarenal aortic dissection is an uncommon vascular disease that is related to hypertension, hyperlipidemia, and atherosclerosis, and may be associated with infrarenal abdominal aortic aneurysm formation. The presence of dissection does not appear to increase the risk of complication or mortality for repair of concomitant aneurysm or for treatment of stenosis.

Multi-layer Flow-modulating Stents for Thoraco-abdominal and Peri-renal Aneurysms: The UK Pilot Study

There remains a population of patients with aortic aneurysms that cannot be treated by conventional endovascular means. Multi-layer flow modulating stents (MFMS) are a novel approach for the treatment of aortic aneurysm; this study reports outcomes of a UK pilot study of first-generation MFMS in thoraco-abdominal (TAAA) and perirenal aneurysms (PAA) in patients who were also unfit for open surgery. Patients with TAAA and PAA unfit for open surgery and with no conventional options for endovascular repair were recruited. Follow-up included CTA at 1, 3, 6, and 12 months, then annually. Outcome measures included 30 day mortality, growth-free survival, branch vessel patency, complications, re-intervention, and maximal aortic diameter. MFMS were implanted in 14 patients (6 PAA, 8 TAAA) between October 2011 and March 2014 with one (7%) 30 day death and 11 (79%) surviving to 12 months. The median aneurysm growth was 9 mm in the first 12 months following implantation. On mean follow-up of 22.8 months, seven (50%) patients had died including one confirmed rupture. AAA diameter remained stable in only two of the surviving patients. Fifty of 51 covered aortic branches remained patent with no embolic episodes or symptoms of ischaemia in any patient. MFMS dislocation occurred in four patients, leading to re-intervention in two. A total of six re-interventions were performed in five patients (35%) with one post-re-intervention death. These first-generation MFMS were unstable and dislocated frequently. It is uncertain whether MFMS implantation influenced the natural history of these aneurysms as none decreased in size, but two remain stable after a mean of 22.8 months. Although side branch patency was maintained, our results do not support the continued use of these first-generation devices. Further development is needed if this technology is to have a role in treatment of aortic aneurysm.

Commentary on ‘Rupture of Abdominal Aortic Aneurysms in Patients under Screening Age and Elective Repair Threshold’

patients and larger aneurysms, respectively. 3 Interestingly, 18.3% of all patients were younger than the universally accepted screening age of 65 years, demonstrating also a gender specific difference (21.4% of men and 3.0% of women were younger than 65 years). This proportion was even larger for smokers, who were more likely to present with an early RAAA than non-smokers, with 28.4% of smokers being under the screening age. These results come as no surprise. Our guidelines acknowledge the fact that a significant number of ruptures occur in individuals younger than 65 years, with the reported proportion varying from 5% to 18%. 2 In agreement with the authors’ findings (18.3% of all patients being below the generally accepted screening age of 65 years), in our personal unpublished series of RAAA, 17% of all patients were younger than 65 years (17.5% and 9.1% for the subgroup of men and women, respectively). In the landmark ADAM study, the mean unadjusted prevalence of AAA 4 cm in male smokers in the two age groups of 55e64 years and 65e79 years was 1.2% and 2.4%, respectively, 1 indicating that restricting AAA screening to the latter group of patients will miss 33% of all AAAs in this population; these observations fit perfectly with the 28.4% frequency of ruptured AAAs in smokers younger than 65 reported by the authors. According to the guidelines, screening should be considered at an earlier age for those at higher risk of AAA, 2,4 such as male smokers, males and also females with a family history of a AAA, or in the presence of any atherosclerotic vascular disease or other risk factors. Obviously a second screening scan would be required at a later stage. According to the authors’ study, 6% of men and 12% of women had a RAAA below the suggested repair diameter threshold of 55 mm and 52 mm, respectively. Since the mean AAA diameter was significantly lower in women than in men, females had an odds ratio of 3.2 compared with men for experiencing rupture of a small (O < 55 mm) AAA in a logistic regression analysis. In the UKSAT study, death was attributable to a ruptured AAA in 5% of men and 14% of women who died, 5 indicating firstly the need to lower the repair threshold for women, secondly the necessity for vigorous follow up of real world patients with a small AAA, and thirdly a commitment to more research on identifying markers predicting future rupture of small AAAs.

Selective Intra-procedural AAA sac Embolization During EVAR Reduces the Rate of Type II Endoleak

The pre-treatment presence of at least six efferent patent vessels (EPV) from the AAA sac and/or AAA thrombus volume ratio (VR%) <40% are considered to be positive predictive factors for persistent type II endoleak (ELIIp). The aim of the present study was to evaluate the effectiveness of sac embolization during EVAR in patients with pre-operative morphological risk factors (p-MRF) for ELIIp. Patients undergoing EVAR and intra-procedural AAA sac embolization (Group A, 2012-2013) were retrospectively selected and compared with a control group of patients with the same p-MRF, who underwent EVAR without intra-procedural sac embolization (Group B, 2008-2010). The presence of ELIIp was evaluated by duplex ultrasound at 0 and 6 months, and by contrast enhanced ultrasound at 12 months. The association between AAA diameter, age, COPD, smoking, anticoagulant therapy, and AAA sac embolization with ELIIp was evaluated using multiple logistic regression. The primary endpoint was the effectiveness of the intra-procedural AAA sac embolization for ELIIp prevention. Secondary endpoints were AAA sac evolution and freedom from ELIIp and embolization related re-interventions at 6-12 months. Seventy patients were analyzed: 26 Group A and 44 Group B; the groups were homogeneous for clinical/morphological characteristics. In Group A the median number of coils positioned in AAA sac was 4.1 (IQR 1). There were no complications related to the embolization procedures. A significantly lower number of ELIIp was detected in Group A than in Group B (8/26 vs. 33/44, respectively, p<.001) at discharge, and this was confirmed at 6-12 months (7/26 vs. 30/44 respectively, p=.001, and 5/25 vs. 32/44, respectively, p<.001). On multivariate analysis, intra-procedural AAA sac embolization was the only factor independently associated with freedom from ELIIp at 6 (OR 0.196, 95% CI 0.06-0.63; p=.007) and 12 months (OR 0.098, 95% CI 0.02-0.35; p<.001). No differences in median AAA sac diameter shrinkage were detected between the two groups at 6-12 months (p=.42 and p=.58, respectively). Freedom from ELIIp related and embolization related re-interventions was 100% in both groups, at 6 and 12 months. Selective intra-procedural AAA sac embolization in patients with p-MRF is safe and could be an effective method to reduce ELIIp. Further studies are mandatory to support these results at long-term follow up.

Distance of the alveolar antral artery from the alveolar crest. Related factors and surgical considerations in sinus floor elevation.

BackgroundIn a variable proportion of maxillary sinuses alveolar antral artery is located close to the residual ridge, increasing the chances for haemorrhagic complications during sinus floor elevation procedures.Material and MethodsRetrospective observational study of CBCT explorations performed for implant-treatment planning. The upper first molar area was selected for this study. The relative uncertainty (standard deviation of the measurement divided by its mean and expressed as a percentage from 0% to 100%) was chosen for determining the observational errors. For modeling the chances of AAA detection, the generalized additive models (GAM) approach was chosen.ResultsA total of 240 maxillary sinuses were studied (46.25% males) whose median median age was 58 years old (IQR: 52-66). Univariate models showed that the chances for an AAA-alvelar crest distance ≤15mm increase in wider sinuses with lower, subsinusally edentulous crests. When distance is considered as a continuous variable, the best mutivariate model showed an explained deviance of 67% and included AAA diameter, distance AAA-sinus floor, sinus width, and shape, height and width of the residual ridge. Thinner AAAs are found closer to the crest (within the ≤15mm safe distance).ConclusionsBearing in mind the inclusion criteria and the limitations of this investigation, it is concluded that there is a high proportion of maxillary sinuses where AAA describes a course close to the alveolar crest (≤15mm), which was classically considered a safe distance for SFE. This position is related to the presence of atrophic crests (depressed ridge form) and wide maxillary sinuses where the distance of the vessel to the floor of the sinus is small. This information may permit a better surgical planning of SFE procedures. Key words:Cone-beam computed tomography, blood vessels, sinus floor augmentation, intraoperative complications.

Endovascular Treatment of Inflammatory Infrarenal Aortic Aneurysms.

The aim of this study was to evaluate short- and midterm outcomes of endovascular aneurysm repair in patients with inflammatory abdominal aortic aneurysm (IAAA) focusing on changes in perianeurysmal inflammation and hydronephrosis. A retrospective study was performed considering data prospectively gathered from 1998 to 2013 in 3 centers. Patient demographics, preoperative clinical characteristics, clinical presentation, preoperative imaging measurements, procedural, and postoperative data were collected. Main outcome was to define evolution of periaortic fibrosis and hydronephrosis at computed tomography angiography (CTA) during follow-up. A total of 22 patients (male n = 20; mean age 70.9 years ± 9.3) were included (mean AAA diameter: 58 mm ± 11, symptomatic: 50%, ruptured: 9.1%). Hydroureteronephrosis was preoperatively diagnosed by CTA in 6 (27.3%) cases. Median clinical follow-up was 2.2 years (range 0.1-14.5). Nine patients died during follow-up. At 1, 2, 4, and 6 years, overall survival was 85.4%, 74.3%, 56.6%, and 49.5%, respectively. Among these 13 patients with CTA follow-up, the mean AAA diameter was 56.2 mm ± 15.5, and progression of sac diameter was detected in 1 (7.7%) patient. Median maximum thickness of perianeurysmal inflammation was 5 mm (range 2-11) and decreased/remained unchanged in 92.3% of patients. Regression of hydroureteronephrosis occurred in 3 of 5 patients available for follow-up. There were no cases of de novo hydroureteronephrosis. Endovascular treatment of IAAA has comparable short-term outcomes with non-IAAA. During midterm follow-up, aneurysm sac progression is rare, and perianeurysmal fibrosis decreases or remains unchanged in most cases. Hydronephrosis regression can occur in some but not all instances and thus warrants close surveillance.

Abstract 20153: Predicting the Need for Transfusions in Endovascular Aneurysm Repair (EVAR)

Purpose: The majority of patients undergoing EVAR do not require blood transfusion, yet blood type and screen (T&amp;S) is routinely performed. Identifying patients in whom T&amp;S can be avoided presents a substantial cost saving opportunity. Hypothesis: We hypothesized that intraoperative blood transfusions can be predicted preoperatively. Methods: Using the Vascular Study Group of New England database from 2003-2014, we performed a retrospective review of 4700 patients who underwent EVAR. The cohort was split randomly into a training (60%) and validation (40%) set. A backwards logistic regression analysis was performed to identify predictors of intraoperative blood transfusion in the training set. The model was then tested in the validation set to estimate the receiver operating curves (ROC) and goodness of fit. Results: Preoperative hemoglobin, urgency (elective, symptomatic, or ruptured), age, maximal anterior-posterior AAA diameter, female gender, and history of CHF (asymptomatic, mild, moderate, or severe) were all significant predictors of intraoperative blood transfusions. The c-statistic for our model was .82 in the training set and .84 in the validation set, and the Hosmer-Lemenshow goodness-of-fit statistic was 0.99. Conclusions: Intraoperative blood transfusions can be routinely predicted preoperatively. Avoidance of T&amp;S in low risk populations provides a substantial cost-saving opportunity.

Multi-layer Flow-modulating Stents for Thoraco-abdominal and Peri-renal Aneurysms: The UK Pilot Study

There remains a population of patients with aortic aneurysms that cannot be treated by conventional endovascular means. Multi-layer flow modulating stents (MFMS) are a novel approach for the treatment of aortic aneurysm; this study reports outcomes of a UK pilot study of first-generation MFMS in thoraco-abdominal (TAAA) and perirenal aneurysms (PAA) in patients who were also unfit for open surgery. Patients with TAAA and PAA unfit for open surgery and with no conventional options for endovascular repair were recruited. Follow-up included CTA at 1, 3, 6, and 12 months, then annually. Outcome measures included 30 day mortality, growth-free survival, branch vessel patency, complications, re-intervention, and maximal aortic diameter. MFMS were implanted in 14 patients (6 PAA, 8 TAAA) between October 2011 and March 2014 with one (7%) 30 day death and 11 (79%) surviving to 12 months. The median aneurysm growth was 9 mm in the first 12 months following implantation. On mean follow-up of 22.8 months, seven (50%) patients had died including one confirmed rupture. AAA diameter remained stable in only two of the surviving patients. Fifty of 51 covered aortic branches remained patent with no embolic episodes or symptoms of ischaemia in any patient. MFMS dislocation occurred in four patients, leading to re-intervention in two. A total of six re-interventions were performed in five patients (35%) with one post-re-intervention death. These first-generation MFMS were unstable and dislocated frequently. It is uncertain whether MFMS implantation influenced the natural history of these aneurysms as none decreased in size, but two remain stable after a mean of 22.8 months. Although side branch patency was maintained, our results do not support the continued use of these first-generation devices. Further development is needed if this technology is to have a role in treatment of aortic aneurysm.

Systolic Sac Pressure Index for the Prediction of Persistent Type II Endoleak for 12 Months After Endovascular Abdominal Aortic Aneurysm Repair.

To assess the relationship between the systolic sac pressure index (SPI) and the presence of endoleaks 12 months after endovascular abdominal aortic aneurysm repair (EVAR). We performed a single-center prospective trial of consecutively treated patients. SPI (calculated as systolic sac pressure/systolic aortic pressure) was measured by catheterization immediately after EVAR. Contrast-enhanced computed tomography was scheduled 12 months after EVAR to detect possible endoleaks. Data were available for 34 patients who underwent EVAR for an AAA. Persisting type II endoleak was found in 8 patients (endoleak-positive group) but not in the other 26 patients (endoleak-negative group). The mean ± standard deviation SPI was significantly greater in the endoleak-positive group than in the endoleak-negative group (0.692 ± 0.048 vs. 0.505 ± 0.081, respectively; P = .001). Receiver-operating characteristic curve analysis revealed that an SPI of 0.638 was the optimum cutoff value for predicting a persistent endoleak at 12 months with high accuracy (0.971; 33/34), sensitivity (1.00), and specificity (0.962) values. The mean change in AAA diameter was -4.28 ± 5.03 mm and 2.22 ± 4.54 mm in patients with SPI of <0.638 or ≥0.638, respectively (P = .002). Patients with an SPI of ≥0.638 immediately after EVAR were more likely to have a persistent type II endoleak at 12 months with an accuracy of 0.971, and showed increases in aneurysm sac diameter compared with patients with an SPI of <0.638.

Validation of pre-procedural aortic aneurysm volume calculations to estimate procedural fill volume of endobags in endovascular aortic sealing

Endovascular aortic sealing (EVAS) with a sac anchoring endoprosthesis excludes abdominal aortic aneurysms based on polymer filling of endobags. Primary objective was to assess the reliability of pre-procedural computed tomography (CT) scans based calculations of required endobag volume in relation to intraoperative volume of the endobags. Forty elective EVAS patients were included. Pre-procedural estimations of endobag volume were based on CT segmentations of aortic flow lumen volume, including both automated and manually-adjusted segmentations, performed by two experienced users. Additionally, changes in maximum AAA diameter, thrombus volume and total AAA volume were calculated from pre- and post-procedural CT scans. Automatically determined volumes were comparable to manually-adjusted calculations (75.3 vs. 75.7 mL) and inter-observer agreement regarding pre-EVAS calculations of prefill volume appeared almost perfect with an intra-class correlation coefficient of 0.98 (95% CI: 0.96-0.99). The mean pressure of the endobags was 185 mmHg. Manually-adjusted pre-procedural volume calculations underestimated procedural volume of the endobags (-11.3±9.9 mL). Differences between pre-EVAS and procedural volume measurements were independent from endobag pressure (r=-0.06, P=0.72), prepocedural thrombus volume (r=-0.303, P=0.057) and changes in total AAA volume (r=0.02, P=0.91). A significant association was determined between differences in pre-EVAS and endobag volume versus changes in thrombus volume pre- and post-procedural (r=0.39, P=0.01). In this validation study, pre-procedural volume measurements underestimate the actual fill volume of the endobags. It should be advised to perform a prefill of the endobags during the EVAS procedure.

Systematic review and meta-analysis of migration after endovascular abdominal aortic aneurysm repair

To identify patients who are under higher threat for migration because of an old generation stent graft application. A systematic review and meta-analysis of the literature was undertaken to identify all studies which included older generation endografts and data reporting on graft migration after EVAR. Outcome data were pooled and combined, and were calculated using fixed or random effects models. From 2000 to 2014, 22 retrospective studies were identified reporting on stent- graft migration after EVAR (8.6%). From those patients, 39% received re-intervention with the mean time of identification ranging from 12 to 36 months. Six of these retrospective nonrandomized studies were eligible for meta-analysis. AAA diameter (AAA diameter: 0.719 mm; 95% confidence interval [CI]: 0.00065-1.4384 mm; p = 0.00497) and neck length (neck length: 4.36 mm; 95% CI: 1.3277-7.394; p = 0.0048) were the only significant factors associated with stent- graft migration. Neck diameter and neck angulation did not have any important influence on stent-graft migration. Patients with large AAA and short necks who were treated with older generation stent grafts such as AneurX and Talent are in higher risk for endograft migration than others. Stent- graft migration consists of an insidious and underestimated threat.

49. Gender Differences In Aortic Neck Morphology In Patients With Abdominal Aortic Aneurysms Undergoing EVAR

Introduction and Objectives: Prior studies have alluded to gender differences in aortic neckmorphology resulting in anatomic exclusion of some women from EVAR. The objective of this study is to correlate gender differences in aortic neck morphology and changes in the neck and aneurysm sac after EVAR. Methods: A retrospective review of consecutive EVARs performed for infrarenal AAA was conducted from 2004 to 2013 at a single institution. Preand post-operative imaging studies were utilized to measure aortic neck length and diameter, shape, and angulation, aneurysm sac diameter. Volumetric analysis of neck thrombus burden was performed using TeraRecon . Results: 146 patients met inclusion criteria 21% were women with a mean age of 75.5 (p1⁄40.724) with comparable baseline comorbidities to men. Neck angulation was greater in women 23.9 vs 13.5 (P<0.028). The percent thrombus of the aortic neck was greater in female patients at 35.7% vs 30%(P1⁄40.02). Preoperative AAA diameter

Late mortality in females after endovascular aneurysm repair

BackgroundAbdominal aortic aneurysm (AAA) rupture is an adverse arterial remodeling event with high mortality risk. Because females have increased rupture risk with smaller AAAs (<5.5 cm), many recommend elective repair before the AAA reaches 5.5 cm. Elective repair improves survival for large AAAs, but long-term benefits of endovascular aneurysm repair (EVAR) for small AAAs in females remain less understood. The objective of this study was to identify if differences in late mortality exist between females undergoing elective EVAR at our institution for small and/or slow-growing AAAs compared with those who meet standard criteria. MethodsWe retrospectively analyzed all patients that underwent EVAR for infrarenal AAA from June, 2009–June, 2013. We excluded patients that were male, treated emergently or for iliac artery aneurysm, and that received renal and/or mesenteric artery stenting. Patients did not meet anatomic criteria if preoperative AAA diameter was <5.5 cm or enlarged <0.5 cm over 6 mo. Late mortality was assessed from the social security death index. ResultsThirty-six of 162 elective EVAR patients (22.2%) were female (mean follow-up, 37.2 mo). Twenty patients (55.6%) met AAA size and/or growth criteria, whereas 16 (44.4%) did not meet criteria. Despite comparable demographics, comorbidities, and complications, patients that did not meet criteria had higher late mortality (37.5% versus 5%; P = 0.03) with a trend toward increased reoperation rate (25% versus. 5%; P = 0.48). Meeting size and/or growth criteria decreased odds of late death (odds ratio, 0.09; 95% confidence intervals, 0.01–0.83). ConclusionsThere is increased late mortality in females receiving elective EVAR at our institution for small and/or slow-growing AAAs. This late mortality may limit the benefits of EVAR for this population.