Intravascular Ultrasound Versus Computed Tomography Angiography in Sizing and Operative Management of Endovascular Aortic Aneurysm Repair.

OBJECTIVES: An abdominal aortic aneurysm (AAA) is a potentially life-threatening condition, the management of which has dramatically evolved over the past 2 decades with an increasing tendency toward endovascular repair (EVAR) rather than open surgical repair. Classically, contrast-enhanced multislice computed tomography (CT) angiography (CTA) is performed preoperatively for procedure sizing and EVAR planning. This entails voluminous contrast injection with risk of allergic reaction, nephropathy, and radiation exposure. Intra-vascular ultrasound (IVUS) has been increasingly used to guide EVAR procedures intraoperatively. The aim of this study is to investigate the accuracy of IVUS in sizing AAAs, device selection, and EVAR planning compared to the gold standard CTA. DESIGN: This is a prospective observational study enrolling 10 patients who underwent standard infrarenal EVAR procedures performed for unruptured infrarenal AAAs over the course of 1 year. All patients had a preoperative CTA done upon which aneurysm sizing and device planning were performed, and the measurements obtained were compared to those obtained from intraoperative IVUS. METHODS: All participating patients had unruptured infrarenal AAA, had no renal impairment, and had anatomical suitability for EVAR according to the instructions for use (IFU) of the device manufacturer. Primary endpoint was comparing anatomical measurements recorded by IVUS with those obtained from the preoperative CTA. RESULTS: Mean age was 65.6 (±6.19), all patients were males and hypertensives and 4 (40%) had a positive family history for AAA. On comparing mean measurements taken by CTA and IVUS, there was no statistically significant differences with exception of maximal aortic diameter and aortic diameter at site of bifurcation (both p-values <.001). There were no statistically significant differences in length measurements between the 2 imaging modalities. Computed tomography angiography was more associated with neck thrombus detection, and IVUS was more associated with calcification detection. CONCLUSION: Although CT angiography is still the gold standard imaging modality for AAA, IVUS use is very beneficial in EVAR sizing and planning, in addition to intra-operative guidance of the procedure, saving the patient significant time, contrast administration, and radiation exposure, especially in patients with renal impairment and contrast allergy. CLINICAL IMPACT: A preoperative CT angiogram is the gold standard required investigation for planning and sizing EVARs, with subsequent contrast injection entailing a risk of contrast induced nephropathy and allergic reactions. IVUS has been used as an adjuvant technique to guide EVAR stent graft deployment. However, our study concluded that it can also be reliably used in sizing and planning of the EVAR stent graft along with complementary non contrast imaging, especially in patients with high risk for contrast induced nephropathy and contrast allergy.

Comparing the Effects of Radial and Jacketed Laser Tip Fibers on Outcome of Endovenous Laser Ablation of Lower Limb Truncal Venous Reflux.

BACKGROUND: Saphenous vein reflux is one of the leading causes of cosmetic and functional disabilities. The recent European Society of Vascular Surgery guidelines recommend endovenous thermal ablation over surgery or sclerotherapy for the treatment of great saphenous vein (GSV) reflux in patients with chronic venous disease. The aim of this study is to compare different laser fiber tip configurations to outcome regarding technical success and incidence of complications. DESIGN: A retrospective analysis conducted on patients with documented GSV reflux from 2020 to 2022, comparing baseline parameters and outcome between 2 groups of laser tip fibers used; radial tip and jacketed tip. Primary end point was technical success. Secondary endpoints included incidence of complications in each group, and VCSS score difference in both groups. METHODS: Inclusion criteria entailed patients with primary varicose veins over the age of 18 years, free from malignancy, hematological disorders, and having documented GSV reflux of more than 0.5 sec. All patients had endovenous laser ablation (EVLA) of the GSV, with complementary foam sclerotherapy or ambulatory phlebectomies as required. RESULTS: A total of 74 patients underwent EVLA (85 limbs). Fifty-four were done using the radial laser fibers, and 32 using jacketed fibers. Technical success was achieved in 78 limbs (92.9%), 6 limbs (7.1%) had recanalization of the proximal 3 cm of the GSV at 1 month, 2 patients experienced hematomas, and 5 patients had superficial vein thrombosis. There was no significant association between postoperative pain, bruising, recanalization, hematoma formation, and superficial vein thrombosis with different laser fiber tip configurations (P-value 0.95, 0.6, 0.18, 1, and 1, respectively), nor was there any significant difference in VCSS between them (P-value 0.14).Technical success was 90% in the jacketed fibers and 94.1% in the radial fibers group (P-value 0.18). CONCLUSIONS: Neither does laser fiber tip configuration nor its make have a significance on outcome of EVLA of GSV reflux. Both radial and jacketed laser fiber tips exhibit similar safety and efficacy in EVLA.

Novel slag/natural rubber composite as flexible material for protecting workers against radiation hazards.

This work is an attempt to employ the electric arc furnace (EAF) slag as a by-product material to develop an alternative and environmentally friendly material for gamma-radiation protection applications such as in medical and industrial areas. For this purpose, different concentrations of micro-sized EAF slag (0, 20, 40, 60, 80, 100, 500, and 800 phr) were incorporated as fillers in the natural rubber (NR) matrix to produce the shielding composites. In addition, nano-sized EAF slag particles were prepared by using a high-energy ball milling technique to investigate the effect of particle size on the gamma-radiation shielding properties. The synthesized micro and nano EAF/NR composites were tested as protective materials against gamma-radiation by employing NaI(Tl) scintillation detector and standard radioactive point sources (152Eu, 137Cs, 133Ba, and 60Co). Different shielding parameters such as linear and mass attenuation coefficient, half value layer (HVL), tenth value layer, mean free path, effective atomic number (Zeff), and effective electron density (Neff) were determined to assess the radiation shielding capability of the EAF/NR composites. Furthermore, equivalent atomic number (Zeq) and the exposure buildup factor values for photon energy in the range from 0.015 to 15 MeV were also computed by Geometric Progression method. The experimental results of micro EAF/NR composites showed that at 121.78 keV, EAF0 composite (without EAF slag content) had the lowest µ value of 0.1695 cm-1, while the EAF800 composite (which was loaded with 800 phr of micro EAF slag) had the highest µ value of 0.2939 cm-1 at the same energy, which in turn decreases the HVL from 4.09 to 2.36 cm, respectively. Therefore, increasing the filler weight fractions of EAF slag in the NR matrix, increases the shielding properties of the composites. Moreover, the NR composite reinforced with 800 phr of nano EAF slag has better gamma-radiation shielding efficiency compared to that filled with 800 phr of micro EAF slag. The success of this work was to prepare a flexible, lightweight, low-cost, and lead-free material with better shielding capability.

Starch functionalization of iron oxide by-product from steel industry as a sustainable low cost nanocomposite for removal of divalent toxic metal ions from water.

Heavy metal removal by waste material from different industry has become one of the main economical approaches for zero waste industrial activity. Therefore, iron oxide fine waste by-product from steel industry was converted into nanoparticulates (Fe2O3 NPs) and further crosslinked with starch as a good stabilizer and biodegradable polymer using formaldehyde to form Fe2O3 NPs-Starch nanocomposite. The scanning electron microscope (SEM) showed the average particle size (40-70 nm). The sorption behavior of this nanocomposite was investigated using Pb(II), Hg(II) and Cd(II). Different factors such as solution pH, contact time, nanocomposite dosage and metal concentration were monitored to determine the adsorptive capacity. Langmuir, Temkin, Freundlich and Dubinin-Radushkevich models were employed to study the adsorption isotherms. The maximum sorption capacities were 2000 mg g-1 for Pb(II), 133.3 mg g-1 for Hg(II) and 322.58 mg g-1 for Cd(II). The results referred that Hg(II) and Cd(II) were best fitted by all models except Pb(II) obeyed the Freundlich isotherm model only. The Fe2O3 NPs-Starch nanocomposite emphasized its potential application as a sustainable low cost nanocomposite for metals extraction from tap water, marine water and industrial wastewater with percentage recovery 93-97%, 70-94% and 76-93%, respectively.