Endograft migration after thoracic endovascular aortic repair.

OBJECTIVE: The objective of this study was to evaluate the incidence, timing, and potential risk factors of late endograft migration after thoracic endovascular aortic repair (TEVAR). METHODS: A retrospective analysis was conducted of 123 patients receiving TEVAR for thoracic aortic aneurysms (TAAs), dissections, penetrating aortic ulcer, intramural hematoma, or traumatic transection between January 2005 and December 2015 with a minimum imaging-based follow-up of 6 months. Imaging analysis was performed by three independent readers. Migration was defined according to the reporting standards as a stent graft shift of >10 mm relative to a primary anatomic landmark or any displacement that led to symptoms or required therapy. A standardized measurement protocol in accordance with the reporting guidelines was used. Median follow-up was 3 years (range, 0.5-10 years). RESULTS: Migration occurred in nine (7.3%) patients and took place at the proximal landing zone (n = 1), overlapping zone (n = 4), or distal landing zone (n = 5), resulting in type I or type III endoleaks in 44% (n = 4/9) of the cases. All cases of migration with endoleaks underwent reintervention; 75% (n = 3/4) of the migration associated with endoleaks could have been identified on previous imaging before an endoleak occurred. Freedom from migration was 99.1% after 1 year, 94.0% after 3 years, and 86.1% after 5 years. Aortic elongation and TAA were identified as predisposing factors for migration (P = .003 and P = .01, respectively). No influence of the proximal landing zone (zone 0-4), type of aortic arch (I-III), or type of endograft on the incidence of migration was found. CONCLUSIONS: Graft migration after TEVAR occurs in a relevant proportion of patients, predominantly in patients with TAA and aortic elongation. Follow-up imaging of these patients should be specifically evaluated regarding the occurrence of migration.

Iron-enhanced sand filters: Multi-year urban runoff (stormwater) quality performance.

Untreated urban runoff (stormwater) is a major pathway for contaminants, e.g., nutrients and metals, to receiving waters. Where eutrophication occurs, dissolved phosphorus (DP) treatment is often necessary to protect receiving waters, yet few practical methods exist. Iron-enhanced sand filters (IESFs) have successfully treated DP in laboratory and limited field studies. Yet, multi-year-IESF studies to understand reportedly variable performance are unavailable. Herein, nine IESFs were sampled from 2015 to 2018 (528 samples; 70 rainfall-runoff events). Analysis focused on influent/effluent concentrations and removal efficiencies alongside design and catchment parameters. Overall, IESFs significantly removed most total and dissolved metal analytes. Generally, phosphorus removal efficiencies correlated positively with influent concentrations and IESF:catchment area ratios, demonstrating the importance of proper sizing and siting. For all paired influent-effluent samples, respective median total phosphorus, orthophosphate, and DP removal efficiencies were 33 %, 41 %, and 13 %, and respective median effluent concentrations were 120, 25, and 75 (µg/L); with two malfunctioning sites omitted, these respective concentrations were 92, 11, and 47, which better matched relevant goals and (indirectly applicable) standards. Nonetheless, phosphorus removal efficiency and effluent concentrations varied significantly across IESFs and events. Seasonality appeared influential, yet variable influent concentrations confounded spatiotemporal removal efficiency comparisons. Thus, compared to removal efficiencies, effluent concentrations may be better indicators of receiving water risk/benefit and of equal importance for water quality crediting. Although 122 influent-effluent pairs were analyzed, a greater sample size would allow multivariate hypothesis tests with additional predictors. Overall, in this multi-site-year study, most IESFs performed at (n = 5) or near (n = 2) phosphorus effluent concentration and less-so, removal efficiency benchmarks. This research provides new quantitative knowledge on long-term IESF performance for real-world conditions and goals. Research recommendations include multivariate dimension reduction studies and comprehensive, effective information transfer to improve IESF understanding and performance and address practitioner needs, e.g., for refined design, operation, and assessment guidance.

Time-Resolved Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography in Patients with Chronic Expanding and Stable Aortic Dissections.

Objective: To prospectively evaluate our hypothesis that three-dimensional time-resolved contrast-enhanced magnetic resonance angiography (TR-MRA) is able to detect hemodynamic alterations in patients with chronic expanding aortic dissection compared to stable aortic dissections. Materials and Methods: 20 patients with chronic or residual aortic dissection in the descending aorta and patent false lumen underwent TR-MRA of the aorta at 1.5 T and repeated follow-up imaging (mean follow-up 5.4 years). 7 patients showed chronic aortic expansion and 13 patients had stable aortic diameters. Regions of interest were placed in the nondissected ascending aorta and the false lumen of the descending aorta at the level of the diaphragm (FL-diaphragm level) resulting in respective time-intensity curves. Results: For the FL-diaphragm level, time-to-peak intensity and full width at half maximum were significantly shorter in the expansion group compared to the stable group (p = 0.027 and p = 0.003), and upward and downward slopes of time-intensity curves were significantly steeper (p = 0.015 and p = 0.005). The delay of peak intensity in the FL-diaphragm level compared to the nondissected ascending aorta was significantly shorter in the expansion group compared to the stable group (p = 0.01). Conclusions: 3D TR-MRA detects significant alterations of hemodynamics within the patent false lumen of chronic expanding aortic dissections compared to stable aortic dissections.

Effects of land use on ground water quality in the Anoka Sand Plain Aquifer of Minnesota.

We began a study, in 1996, to compare ground water quality under irrigated and nonirrigated agriculture, sewered and nonsewered residential developments, industrial, and nondeveloped land uses. Twenty-three monitoring wells were completed in the upper meter of an unconfined sand aquifer. Between 1997 and 2000, sampling occurred quarterly for major ions, trace inorganic chemicals, volatile organic compounds (VOCs), herbicides, and herbicide degradates. On single occasions, we collected samples for polynuclear aromatic hydrocarbons (PAHs), perchlorate, and coliform bacteria. We observed significant differences in water chemistry beneath different land uses. Concentrations of several trace inorganic chemicals were greatest under sewered urban areas. VOC detection frequencies were 100% in commercial areas, 52% in sewered residential areas, and <10% for other land uses. Median nitrate concentrations were greatest under irrigated agriculture (15,350 microg/L) and nonsewered residential areas (6080 microg/L). Herbicides and degradates of acetanilide and triazine herbicides were detected in 86% of samples from irrigated agricultural areas, 68% of samples from nonirrigated areas, and <10% of samples from other land uses. Degradates accounted for 96% of the reported herbicide mass. We did not observe seasonal differences in water chemistry, but observed trends in water chemistry when land use changes occurred. Our results show land use is the dominant factor affecting shallow ground water quality. Trend monitoring programs should focus on areas where land use is changing, while resource managers and planners must consider potential impacts of land use changes on ground water quality.