True Brachial Artery Aneurysm after Arteriovenous Fistula for Hemodialysis: Five Cases and Literature Review.

BACKGROUND: The donor artery after a long-standing arteriovenous fistula (AVF) for hemodialysis usually evolves exceptionally toward a true aneurysmal degeneration (AD). The purpose of this article was to describe true brachial artery AD in end-stage renal disease patients after AVF creation, as well as its influencing factors and treatment strategies. METHODS: We present a retrospective, observational, single-center study realized in Caen University Hospital's Vascular Surgery Department from May 1996 to November 2015. The inclusion criteria were true AD of the brachial artery after a vascular access for hemodialysis. A literature research, using the same criteria, was performed on the articles published between 1994 and 2015. The used databases included MEDLINE (via PubMed), EMBASE via OVID, Cochrane Library Database, and ResearchGate. RESULTS: Our series includes 5 patients. Twenty-one articles were found in the literature: 17 case reports, 3 series, and 1 review. The same triggering factors for AD (high flow and immunosuppressive treatment) were found. The mean age at the time of AVF creation, first renal transplantation, and AD's diagnosis were respectively 26 (range 15-49), 29.2, and 48.6 years (range 37-76) in our series versus 34 (range 27-39), 40.4 (range 28-55), and 55.5 years (range 35-75) in cases found in the literature. The time spread after AVF creation and aneurysmal diagnosis was about 20.6 years (range 18-25) in our study versus 20.5 years (range 9-29) in the case reports. Our surgical attitude corresponds principally to that described in the literature. Nevertheless, we describe for the first time one case of arterial transposition to exclude the brachial aneurysm using superficial femoral artery. CONCLUSIONS: Arterial aneurysm is a rare, but significant complication after a long-term creation of hemodialysis access. High flow and immunosuppression may accelerate this process. Young age of the patients may act as a benefic factor and delay the AD. Arterial transposition could be an option in the absence of any venous conduit, if anatomy does not permit the use of prosthetic grafts.

Molecular imaging of endothelial activation and mineralization in a mouse model of accelerated atherosclerosis.

PURPOSE: Preclinical imaging of endothelial activation and mineralization using both positron emission tomography (PET) and magnetic resonance (MR) remains scarce. PROCEDURES: A group of uremic ApoE-/- (Ur), non-uremic ApoE-/- (NUr), and control C57Bl/6 J mice (Ctl) were investigated. Mineralization process was assessed using sodium fluoride ([18F]NaF) PET, and MR imaging combined with intravenous injection of MPIO-αVCAM-1 was used to evaluate endothelial activation. Micro- and macrocalcifications were evaluated by flame atomic absorption spectroscopy and von Kossa staining, respectively. RESULTS: Ur mice showed an active and sustained mineralization process compared to Ctl mice (p = 0.002) using [18F]NaF PET imaging. Calcium plasma level was increased in Ur (2.54 ± 0.09 mM, n = 17) compared to NUr and Ctl mice (2.24 ± 0.01, n = 22, and 2.14 ± 0.02, n = 27, respectively; p < 0.0001). Likewise, vascular calcium content was increased in Ur (0.51 ± 0.06 µg Ca2+ per milligram of dry weight aorta, n = 11) compared to NUr (0.27 ± 0.05, n = 9, p = 0.013) and Ctl (0.28 ± 0.05, n = 11, p = 0.014). Ur mice also had a higher inflammatory state using MPIO-αVCAM-1 MR (p global = 0.01, post hoc analysis Ur vs. Ctl p = 0.003) associated with increased VCAM-1 expression (p global = 0.02). Aortic remodeling at the level of the brachiocephalic trunk, brachiocephalic trunk itself, and aortic arch in Ur mice was also demonstrated using MR. CONCLUSIONS: Preclinical molecular imaging allowed in vivo characterization of the early phase of atherosclerosis. [18F]NaF PET showed early and sustained vascular mineralization in uremic ApoE-/- mice. MPIO-αVCAM-1 MR imaging demonstrated aortic endothelial activation, predominantly in segments with vascular remodeling.

Performance Evaluation of a Dedicated Preclinical PET/CT System for the Assessment of Mineralization Process in a Mouse Model of Atherosclerosis.

PURPOSE: The purpose of this study was to assess the impact of positron emission tomography/X-ray computed tomography (PET/CT) acquisition and reconstruction parameters on the assessment of mineralization process in a mouse model of atherosclerosis. PROCEDURES: All experiments were performed on a dedicated preclinical PET/CT system. CT was evaluated using five acquisition configurations using both a tungsten wire phantom for in-plane resolution assessment and a bar pattern phantom for cross-plane resolution. Furthermore, the radiation dose of these acquisition configurations was calculated. The PET system was assessed using longitudinal line sources to determine the optimal reconstruction parameters by measuring central resolution and its coefficient of variation. An in vivo PET study was performed using uremic ApoE-/-, non-uremic ApoE-/-, and control mice to evaluate optimal PET reconstruction parameters for the detection of sodium [18F]fluoride (Na[18F]F) aortic uptake and for quantitative measurement of Na[18F]F bone influx (Ki) with a Patlak analysis. RESULTS: For CT, the use of 1 × 1 and 2 × 2 binning detector mode increased both in-plane and cross-plane resolution. However, resolution improvement (163 to 62 µm for in-plane resolution) was associated with an important radiation dose increase (1.67 to 32.78 Gy). With PET, 3D-ordered subset expectation maximization (3D-OSEM) algorithm increased the central resolution compared to filtered back projection (1.42 ± 0.35 mm vs. 1.91 ± 0.08, p < 0.001). The use of 3D-OSEM with eight iterations and a zoom factor 2 yielded optimal PET resolution for preclinical study (FWHM = 0.98 mm). These PET reconstruction parameters allowed the detection of Na[18F]F aortic uptake in 3/14 ApoE-/- mice and demonstrated a decreased Ki in uremic ApoE-/- compared to non-uremic ApoE-/- and control mice (p < 0.006). CONCLUSIONS: Optimizing reconstruction parameters significantly impacted on the assessment of mineralization process in a preclinical model of accelerated atherosclerosis using Na[18F]F PET. In addition, improving the CT resolution was associated with a dramatic radiation dose increase.