CT after Endovascular Repair of Abdominal Aortic Aneurysms: Diagnostic Accuracy of Diameter Measurements for the Detection of Aneurysm Sac Enlargement.

PURPOSE: To evaluate the diagnostic accuracy of diameter measurements for the detection of aneurysm volume increase during follow-up after endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: This retrospective study analyzed 100 pairs of follow-up computed tomography scans randomly selected from an EVAR database (male/female ratio, 91/9; mean age, 71 y; bifurcated and aortouniiliac stent grafts, 96% and 4%, respectively; mean interval, 359 d). Five maximum diameter (Dmax) values were measured (anteroposterior, transverse, axial, coronal, and perpendicular). Aneurysm sac volume was measured by manual segmentation and used as the standard of reference. Overall, 37% of patients had a persistent type II endoleak. RESULTS: The anteroposterior, transverse, axial, coronal, and perpendicular Dmax values increased in 39 patients (mean, 4.3 mm), 30 patients (mean, 4.0), 35 patients (mean, 3.9 mm), 43 patients (mean, 3.9 mm), and 41 patients (mean, 4.3 mm), respectively. Aneurysm sac volume increased in 39 patients (mean, 25.7 cm3). The cutoff levels according to the reporting standard for aneurysm sac enlargement (diameter ≥ 5.0 mm, volume ≥ 5.0%) had sensitivity/specificity rates of 29%/95%, 33%/97%, 29%/99%, 33%/93%, and 38%/96%, respectively, for the five Dmax values. The reference standards failed to detect aneurysm volume increase in 72%, 67%, 72%, 61%, and 67% of patients, respectively, with persistent type II endoleak. CONCLUSIONS: Depending on the chosen cutoff value, diameter measurements showed low to moderate sensitivity for the detection of aneurysm volume increase. The diameter measurements failed to detect aneurysm enlargement in a large number of patients with persistent type II endoleak after EVAR of AAA.

CT features of early type II endoleaks after endovascular repair of abdominal aortic aneurysms help predict aneurysm sac enlargement.

PURPOSE: To determine computed tomographic (CT) features of early type II endoleaks associated with aneurysm sac enlargement after endovascular aortic aneurysm repair (EVAR) of abdominal aortic aneurysm. MATERIALS AND METHODS: Institutional review board approval was not required for this retrospective study. The authors reviewed imaging and clinical data from 56 patients (seven women, 49 men; mean age ± standard deviation, 71 years ± 7.9; age range, 52-85 years) with early type II endoleak who had undergone EVAR between December 2002 and December 2011 and who had been followed up with imaging and clinical evaluation for at least 6 months. The number and diameter of all feeding and/or draining arteries were measured, and endoleaks were classified according to their sources into simple inferior mesenteric artery (IMA), simple lumbar artery (LA), complex LA, and complex IMA-LA type II endoleaks. Volume and attenuation of the nidus were measured. Aneurysm enlargement was defined as an increase in the aneurysm volume of more than 5% during follow-up. Simple and multivariate logistic regression analyses were performed to identify independent clinical and imaging variables associated with aneurysm enlargement. RESULTS: Twenty-three of the 56 patients (41%) showed aneurysm sac enlargement during follow-up (mean follow-up, 3.0 years ± 2.0). With the multivariate model, the variables that showed the strongest indicators for aneurysm sac enlargement were complex IMA-LA type II endoleak (odds ratio [OR] = 10.29, P = .004) and the diameter of the largest feeding and/or draining artery (OR = 4.55, P = .013). Patients without complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 3.8 mm and patients with a complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 2.2 mm were at high risk for aneurysm sac enlargement. CONCLUSION: The strongest indicators for aneurysm sac enlargement are complex IMA-LA type II endoleak and the diameter of the largest feeding and/or draining artery.

Inferior mesenteric arterial type II endoleaks after endovascular repair of abdominal aortic aneurysm: are they predictable?

PURPOSE: To evaluate the association of inferior mesenteric arterial (IMA) type II endoleaks in patients undergoing endovascular aortic aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysm with several morphologic parameters. MATERIALS AND METHODS: Approval of the institutional ethical review committee was not required. This was a retrospective review of 322 computed tomographic angiographic studies that were performed in patients before they underwent elective EVAR for infrarenal abdominal aortic aneurysm. Morphologic parameters evaluated were IMA patency, origin of the IMA in relation to the aneurysm sac, diameter of the IMA, the cross-sectional area of the contrast material-enhanced aortic lumen at the level of the IMA ostium, and the number of additional patent aortic side branches from the aneurysm sac. The association of IMA type II endoleaks with each variable was analyzed by using univariate and multivariate logistic regression models. RESULTS: The diameter of the IMA did not influence the development of IMA type II endoleaks (P = .51). The incidence of these endoleaks was significantly higher in patients with greater cross-sectional area of the aortic lumen at the IMA ostium (P < .001). Patients with an IMA type II endoleak had significantly more patent aortic side branches before EVAR than did patients without an endoleak (3.6 ± 1.7 vs 2.2 ± 1.4; P < .001). According to the final logistic regression model that included cross-sectional area of the aortic lumen at the IMA and the number of aortic side branches as independent predictors, risk for IMA type II endoleaks was determined with a sensitivity of 78% (39 of 50) and a specificity of 79% (92 of 116). CONCLUSION: Cross-sectional area of the contrast-enhanced aortic lumen at the level of the IMA ostium and the number of additional patent aortic side branches are associated with the development of IMA type II endoleaks.

Physicochemical analysis of ruthenium(II) sensitizers of 1,2,3-triazole-derived mesoionic carbene and cyclometalating ligands.

A series of heteroleptic bis(tridentate) ruthenium(II) complexes bearing ligands featuring 1,2,3-triazolide and 1,2,3-triazolylidene units are presented. The synthesis of the C^N^N-coordinated ruthenium(II) triazolide complex is achieved by direct C-H activation, which is enabled by the use of a 1,5-disubstituted triazole. By postcomplexation alkylation, the ruthenium(II) 1,2,3-triazolide complex can be converted to the corresponding 1,2,3-triazolylidene complex. Additionally, a ruthenium(II) complex featuring a C^N^C-coordinating bis(1,2,3-triazolylidene)pyridine ligand is prepared via transmetalation from a silver(I) triazolylidene precursor. The electronic consequences of the carbanion and mesoionic carbene donors are studied both experimentally and computationally. The presented complexes exhibit a broad absorption in the visible region as well as long lifetimes of the charge-separated excited state suggesting their application in photoredox catalysis and photovoltaics. Testing of the dyes in a conventional dye-sensitized solar cell (DSSC) generates, however, only modest power conversion efficiencies (PCEs).

Transarterial embolization of type II endoleaks after EVAR: the role of ethylene vinyl alcohol copolymer (Onyx).

PURPOSE: To determine the feasibility and efficacy of transarterial endoleak embolization using the liquid embolic agent ethylene vinyl alcohol copolymer (Onyx). METHODS: Over a 7-year period eleven patients (6 women, 5 men; mean age 68 years, range 37-83 years) underwent transarterial embolization of a type II endoleak after endovascular aortic aneurysm repair using the liquid embolic agent Onyx. Two patients (18 %) had a simple type II endoleak with only one artery in communication with the aneurysm sac, whereas 9 patients (82 %) had a complex type II endoleak with multiple communicating vessels. We retrospectively analyzed the technical and clinical success of transarterial type II endoleak embolization with Onyx. Complete embolization of the nidus was defined as technical success. Embolization was considered clinically successful when volume of the aneurysm sac was stable or decreased on follow-up CT scans. RESULT: Mean follow-up time was 26.0 (range 6-50) months. Clinical success was achieved in 8 of 11 patients (73 %). Transarterial nidus embolization with Onyx was technically successful in 6 of 11 patients (55 %). In three cases the nidus was embolized without direct catheterization from a more distal access through the network of collateral vessels. CONCLUSION: Onyx is a favorable embolic agent for transarterial endoleak embolization. To achieve the best clinical results, complete occlusion of the nidus is mandatory.