[Relationship between Aneurysm Volumetric Changes and Endoleaks after Endovascular Abdominal Aortic Aneurysm Repair].

Objective To evaluate the relationship of volumetric changes and endoleaks after endovascular aneurysm repair(EVAR)for abdominal aortic aneurysms(AAAs). Methods We retrospectively evaluated the clinical and imaging data of 54 patients who had underwent EVAR within 1 month after their aneurysms were detected.All patients received abdominal and pelvic enhanced computed tomography(CTA)for two follow-up visits in Peking Union Medical College Hospital from July 2014 to February 2019.Three-dimensional volumes and maximum diameters on axial CT of the aortic aneurysms were calculated by dedicated semi-automated 3D segmentation software before surgery(V0 and D0),in the 4 th postoperative month(V1and D1),and in the 12 th postoperative month(V2and D2),respectively.The presence or absence of endoleak for each patient with the V1/V0,V2/V0,and V2/V1 were calculated to assess the significance of volume changes with respect to endoleaks and the correlation between volume changes and maximum diameter changes on axial CT images. Results Of the 54 patients,endoleaks were found in 11 patients at the first follow-up visit(4 months after surgery),among whom 8 patients were arranged a second follow-up visit(12 months after surgery),during which endoleaks were found in 5 patients.Fifteen of 43 non-leaked patients underwent a second CTA examination,which revealed endoleak in one case.Patients who did exhibit endoleaks[n =11,V1/V0=1.086(1.033,1.116)]showed significant increases in aneurysm volume when compared with those who did not exhbit endoleaks[n =43,V1/V0=1.019(0.970,1.065)]at the first follow-up visit(Z=-2.695,P=0.007),although no significant difference was found with regard to volume changes between endoleaks(n=6,V2/V0=1.1±0.2,V2/V1=1.0±0.1)and non-endoleaks(n=17,V2/V0=1.0±0.1,V2/V1=1.0±0.1)at the second follow-up visit(t=0.725,P=0.476)as well as between these two follow-up visits(t=-0.021,P=0.984).V0 and D0 were moderately correlated with V1 and D1,respectively(r=0.5,P<0.001)and strongly correlated with V2 and D2,respectively(r=0.8,P<0.001).V1 and D1 were strongly correlated with V2 and D2,respectively(r=0.8,P<0.001). Conclusions The changes of aneurysm volume cannot reliably reflect the occurrence of endoleaks.The change of maximum axial diameter of aneurysm has certain correlation with the changes of aneurysm volume.

The structural atrophy of the aneurysm wall in secondary expanding aortic aneurysms with endoleak type II.

BACKGROUND: Abdominal aortic aneurysm (AAA) has an age-dependent prevalence of 2% to 11% and is a leading cause of death in men aged >65 years if not treated surgically. Today, endovascular aneurysm repair (EVAR) is performed in up to 80% of elective cases and 60% of ruptured cases. Although EVAR improves perioperative, early, and midterm outcomes, it is associated with specific complications, especially endoleaks (ELs). Type II EL occurs in up to 30% of procedures; however, aneurysm sac expansion and rupture are rare, and currently nothing is known about the morphologic changes in this condition. In this study, we investigate the aneurysm wall morphology in secondary expanding human AAA samples after EVAR with persistent type II EL in comparison to nonaneurysmatic control aortic and AAA samples. METHODS: Samples were acquired from the aneurysm sac during retroperitoneal feeder vessel ligation in a cohort of 10 patients with secondary expansion after EVAR and type II EL diagnosed by computed tomography and contrast-enhanced ultrasound. Control tissues included 42 AAAs and 13 control aortae published previously. Hematoxylin and eosin staining and immunohistochemistry for CD3/4/31/68 and Ki67 were performed for morphologic analysis. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assays allowed quantification of apoptosis. Reverse transcription-polymerase chain reaction was used to quantify gene expression and Western blot to quantify collagen expression. RESULTS: Secondary expansion of 33.8% ± 30% during 5 years was seen after EVAR before reoperation. The aneurysm wall after expansion shows significant thinning of the intima-media layer accompanied by a scarcity of cells, with only a little chronic inflammation left compared with AAA samples. Macrophages are seen in abundance, and matrix metalloproteinase expression is significantly upregulated. Relevant apoptosis is not noticed. Fibrous tissue is reduced, and a collagen turnover to different subtypes is noted in comparison to nonaneurysmatic control aorta and AAA. In addition, the transcription factors vascular endothelial growth factor, Kruppel-like factor 4, and BCL2, elevated in AAA, are significantly reduced after secondary expansion. CONCLUSIONS: The aneurysm sac morphology after EVAR with persistent type II EL is characterized by atrophy and proteolysis suggestive of structural weakening. These results should be considered for the follow-up schedule as well as for the potential treatment of this most frequent EVAR complication.

Aortic Neck Anatomic Features and Predictors of Outcomes in Endovascular Repair of Abdominal Aortic Aneurysms Following vs Not Following Instructions for Use.

BACKGROUND: A significant number of patients undergo endovascular repair of abdominal aortic aneurysms (EVAR) outside the instructions for use (IFU). This study will examine various aortic neck features and their predictors of clinical outcomes. STUDY DESIGN: We performed a retrospective analysis of prospectively collected data on EVAR patients. Neck features outside IFU were analyzed. Kaplan-Meier and multivariate analyses were used to predict their effect as single features, or in combination, on outcomes. RESULTS: Fifty-two percent of 526 patients had 1 or more features outside the IFU. The overall technical success rate was 99%, and perioperative complication rates were 7% and 12% for IFU vs outside IFU use, respectively (p = 0.04). Type I early endoleak and early intervention rates were 7% and 10% for IFU vs 18% and 24% for outside IFU (p = 0.0002 and p < 0.0001). At a mean follow-up of 30 months, freedom from late type I endoleak and late reintervention at 1, 2, and 3 years for IFU were 99.5%, 99.5%, and 98.4%, and 99.4%, 98%, and 96.8%; vs 98.9%, 98.1%, and 98.1%, and 97.5%, 96.2%, and 95.2% for outside IFU (p = 0.049 and 0.799), respectively. Survival rates at 1, 2, and 3 years for IFU were 97%, 93.5%, and 89.8%; vs 93.7%, 88.8%, and 86.3% for outside IFU (p = 0.035). Multivariate analysis showed that a neck angle > 60 degrees had odds ratios for death, sac expansion, and early intervention of 6, 2.6, and 3.3, respectively; neck length < 10 mm had odds ratios of 2.8 for deaths, 3.4 for early intervention, 4.6 for late reintervention, and 4.3 for late type I endoleak. CONCLUSIONS: Patients with neck features outside IFU can be treated with EVAR; however, they have higher rates of early and late type I endoleak, early intervention, and late death.

Aortic morphometry at endograft position as assessed by 3D image analysis affects risk of type I endoleak formation after TEVAR.

PURPOSE: The purpose of this study was to identify morphologic factors affecting type I endoleak formation and bird-beak configuration after thoracic endovascular aortic repair (TEVAR). METHODS: Computed tomography (CT) data of 57 patients (40 males; median age, 66 years) undergoing TEVAR for thoracic aortic aneurysm (34 TAA, 19 TAAA) or penetrating aortic ulcer (n = 4) between 2001 and 2010 were retrospectively reviewed. In 28 patients, the Gore TAG® stent-graft was used, followed by the Medtronic Valiant® in 16 cases, the Medtronic Talent® in 8, and the Cook Zenith® in 5 cases. Proximal landing zone (PLZ) was in zone 1 in 13, zone 2 in 13, zone 3 in 23, and zone 4 in 8 patients. In 14 patients (25%), the procedure was urgent or emergent. In each case, pre- and postoperative CT angiography was analyzed using a dedicated image processing workstation and complimentary in-house developed software based on a 3D cylindrical intensity model to calculate aortic arch angulation and conicity of the landing zones (LZ). RESULTS: Primary type Ia endoleak rate was 12% (7/57) and subsequent re-intervention rate was 86% (6/7). Left subclavian artery (LSA) coverage (p = 0.036) and conicity of the PLZ (5.9 vs. 2.6 mm; p = 0.016) were significantly associated with an increased type Ia endoleak rate. Bird-beak configuration was observed in 16 patients (28%) and was associated with a smaller radius of the aortic arch curvature (42 vs. 65 mm; p = 0.049). Type Ia endoleak was not associated with a bird-beak configuration (p = 0.388). Primary type Ib endoleak rate was 7% (4/57) and subsequent re-intervention rate was 100%. Conicity of the distal LZ was associated with an increased type Ib endoleak rate (8.3 vs. 2.6 mm; p = 0.038). CONCLUSIONS: CT-based 3D aortic morphometry helps to identify risk factors of type I endoleak formation and bird-beak configuration during TEVAR. These factors were LSA coverage and conicity within the landing zones for type I endoleak formation and steep aortic angulation for bird-beak configuration.

Predicting aortic complications after endovascular aneurysm repair.

BACKGROUND: Lifelong surveillance is standard after endovascular repair of abdominal aortic aneurysm (EVAR), but remains costly, heterogeneous and poorly calibrated. This study aimed to develop and validate a scoring system for aortic complications after EVAR, informing rationalized surveillance. METHODS: Patients undergoing EVAR at two centres were studied from 2004 to 2010. Preoperative morphology was quantified using three-dimensional computed tomography according to a validated protocol, by investigators blinded to outcomes. Proportional hazards modelling was used to identify factors predicting aortic complications at the first centre, and thereby derive a risk score. Sidak tests between risk quartiles dichotomized patients to low- or high-risk groups. Aortic complications were reported by Kaplan-Meier analysis and risk groups were compared by log rank test. External validation was by comparison of aortic complications between risk groups at the second centre. RESULTS: Some 761 patients, with a median age of 75 (interquartile range 70-80) years, underwent EVAR. Median follow-up was 36 (range 11-94) months. Physiological variables were not associated with aortic complications. A morphological risk score incorporating maximum aneurysm diameter (P < 0·001) and largest common iliac diameter (measured 10 mm from the internal iliac origin; P = 0·004) allocated 75 per cent of patients to a low-risk group, with excellent discrimination between 5-year rates of aortic complication in low- and high-risk groups at both centres (centre 1: 12 versus 31 per cent, P < 0·001; centre 2: 12 versus 45 per cent, P = 0·002). CONCLUSION: The risk score uses commonly available morphological data to stratify the rate of complications after EVAR. The proposals for rationalized surveillance could provide clinical and economic benefits.

Magnetic resonance imaging is more sensitive than computed tomography angiography for the detection of endoleaks after endovascular abdominal aortic aneurysm repair: a systematic review.

OBJECTIVES: The purpose of this systematic review was to examine whether magnetic resonance imaging (MRI) or computed tomography angiography (CTA) is more sensitive for the detection of endoleaks in patients with abdominal aortic aneurysm (AAA) after EVAR. DESIGN: Systematic review. MATERIALS AND METHODS: A systematic electronic search was performed. Articles were included when post-EVAR patients were evaluated by both MRI as index test and CTA as comparison. Methodological quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Primary outcome was the proportion of patients in whom MRI detected additional endoleaks, which were not seen with CTA. RESULTS: Eleven articles were included. The overall methodological quality of the articles was good. In total, 369 patients with 562 MRI and 562 CTA examinations were included. A total of 146 endoleaks were detected by CTA; MRI detected all but two of these endoleaks. With MRI 132 additional endoleaks were found. CONCLUSIONS: MRI is more sensitive compared to CTA for the detection of post-EVAR endoleaks, especially for the detection of type II endoleaks. MRI should be considered in patients with continued AAA growth and negative or uncertain findings at CTA.

Noninvasive visualization of endoleaks after endovascular aortic aneurysm repair through unenhanced MRI with motion-sensitized driven equilibrium preparation: Phantom experiments.

PURPOSE: To optimize imaging parameters for balanced turbo field echo (BTFE) sequence combined with motion-sensitized driven equilibrium (MSDE) preparation for endoleak detection and type classification in phantom experiments. MATERIALS AND METHODS: We prepared four phantoms: a pulsatile flow generator with an aortic aneurysm model simulating no endoleak, and a type-1, type-2, and type-3 endoleak. Throughout the experiments, MSDE-BTFE images with and without flow suppression were obtained at 1.5 T and subtraction images were used for image evaluation. The no-endoleak phantom was imaged using different MSDE-BTFE sequences to optimize the k-space trajectory and evaluate the use of electrocardiogram gating. The relative contrast between flowing saline and background was calculated. Then all phantoms were imaged to determine the optimal velocity encoding (VENC) for endoleak detection and type classification. Three independent observers performed the image evaluation. Consistencies between the interpreted and true results were analyzed using kappa statistics. RESULTS: The 3D low-high k-space trajectory with electrocardiogram gating provided the highest relative contrast. Low VENCs of 2-10 cm/s and high VENCs of 20 cm/s showed perfect consistency in endoleaks detection and type classification, respectively. CONCLUSION: MSDE-BTFE sequences of appropriate VENCs has potential for endoleak detection and type classification, without contrast material.

Lack of thrombus organization in nonshrinking aneurysms years after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: During endovascular abdominal aortic aneurysm repair (EVAR), blood is trapped in the aneurysm sac at the moment the endograft is deployed. It is generally assumed that this blood will coagulate and evolve into an organized thrombus. It is unknown whether this process always occurs, what its time span is, and how it influences aneurysm shrinkage. With magnetic resonance imaging (MRI), quantitative analysis of the aneurysm sac is possible in terms of endoleak volume as well as unorganized thrombus volume and organized thrombus volume. We investigated the presence of unorganized thrombus in nonshrinking aneurysms years after EVAR. METHODS: Fourteen patients with a nonshrinking aneurysm without endoleak on computed tomography/computed tomography angiography underwent MRI with a blood pool agent (gadofosveset trisodium). Precontrast T1-, precontrast T2-, and postcontrast T1-weighted images (3 and 30 minutes after injection) were acquired and evaluated for the presence of endoleak. The aneurysm sac was segmented into endoleak, unorganized thrombus, and organized thrombus by interactively thresholding the differently weighted images. The classification was visualized in real-time as a color overlay on the MR images. The volumes of endoleak, unorganized thrombus, and organized thrombus were calculated. RESULTS: Median time after EVAR was 2 years (range, 1-8.2 years). The average aneurysm sac volume of the patients was 167 ± 107 mL (mean ± standard deviation). Nine patients had an endoleak on the postcontrast T1-w images 30 minutes after injection. On average, the aneurysm sac contained 78 ± 61 mL unorganized thrombus, which corresponded to 51 ± 21 volume-percentage, irrespective of the presence of an endoleak on the blood pool agent enhanced MRI images (independent t-test, P = .8). CONCLUSIONS: In our study group, half of the nonshrinking aneurysm sac contents consisted of unorganized thrombus years after EVAR.

[Hybrid repair of the aortic arch. Santa Marta Hospital initial experience]. / Reparação híbrida do arco aórtico: experiência inicial do Hospital de Santa Marta.

OBJECTIVES: To retrospectively review the hybrid treatment of the aortic arch with supra-aortic debranching and endo- vascular stent-graft repair in a single institution. METHODS: From 2007 to 2010, all patients submitted to aortic debranching procedures were entered into a prospective database analysis. For the present study, only patients with sealing zones 0 and 1, according to the Ishimaru classification, were included. Procedure-related morbimortality was analysed for the open and endovascular procedures. RESULTS: During the study period, we electively performed 6 total aortic debranching and 4 partial aortic debranching procedures in 10 patients. According to the etiology the indications were: 6 aortic arch aneurysms, 2 post-dissection aneurysms, 1 false aneurysm and 1 type I endoleak following TEVAR. The proximal sealing zone was Ishimaru zone 0 in six patients and zone 1 in four patients. The TEVAR procedure was delayed in all patients with a completion success of 80% (1 patient died from ruptured aortic aneurysm; 1 patient denied the second procedure and was lost to follow-up). The 30d mortality rate was 10% (patient mentioned above). The main morbidity was: 1 axillar venous thrombosis, 1 case of subclinical myocardial infarction, 1 case of terminal renal insufficiency and 1 case of prolonged ventilation. No permanent cerebral or peripheral neurologic deficit was noted. CONCLUSIONS: The hybrid repair of the aortic arch is a feasible and reproducible procedure, and our results are similar to the previously published series. Medium and long-term results are necessary to confirm whether the technique can be regarded as a safe alternative to open surgery in high-risk patients.

Endothelial denudation combined with embolization in the prevention of endoleaks after endovascular aneurysm repair: an animal study.

PURPOSE: To test whether combining embolization with endothelial denudation could reduce endoleak persistence and recurrence after endovascular aneurysm repair (EVAR) in an animal model. METHODS: Type I endoleaks with collateral outflow were created in bilateral iliac aneurysms in 12 dogs. In 6 animals (group 1), endoleaks were treated by thrombin injection, with or without mechanical denudation of the endothelium. In the other 6 animals (group 2), simultaneous occlusion and endothelial denudation was induced in one side by treatment with a gel containing ethanol, ethylcellulose, and lipiodol, whereas the other side was treated with saline control. Follow-up ultrasonography and angiography were performed before necropsy and histology at 3 months. RESULTS: Denudation combined with thrombin injection led to higher aneurysm shrinkage than thrombin alone, as shown by the mean relative aneurysm diameter (89% vs. 124% at baseline, p<0.01) and length (61% vs. 82% at baseline, p<0.01). Denudation did not significantly reduce endoleak occurrence (4/6 vs. 6/6); however, endoleaks in denuded aneurysms were significantly smaller and located in areas inaccessible to denudation. Six of the 10 endoleaks seen at 3 months occurred despite complete initial occlusion (recurrent endoleaks). In the gel-treated group, embolized aneurysms did not shrink significantly, and stent-graft thrombosis developed in 3/6 embolized aneurysms; however, the 3 other aneurysms showed no endoleaks, while all 6 saline-treated controls exhibited persistent endoleaks. CONCLUSION: This study demonstrates the role of recanalization in endoleak recurrence and indicates that combining embolization and endothelial denudation could be a promising strategy to prevent endoleak persistence or recurrence after EVAR. However, the sclerosing gel tested in this study is not appropriate since it is prone to migration with resultant stent-graft thrombosis.

[A case report of endoleak type Ib and IIIa combination after endovascular subrenal aneurysm repair]. / Prípad kombinace endoleaku Ib a IIIa typu po zavedení stentgraftu pro subrenální výdut' aorty.

Authors describe a case report of complications and theirs solutions after endovascular abdominal aneurysm repair. There was symptomatic progression of aneurysmal sac due to endoleak type Ib in this patient 4 years after successful stentgraft treatment. Endovascular treatment was done with optimal effect, but aneurysm sac rupture had early become. The patient was urgently operated. The cause of the rupture was endoleak type IIIa, that was diagnosed perioperatively. This complication was solved with direct suture of disconnected parts of stentgraft. Despite of postoperative complications the patient vas released home in a good condition after 23 days of hospital staying. Endoleaks and their management are discussed in the article.