TEVAR: Endovascular Repair of the Thoracic Aorta.

The development of thoracic endovascular aortic repair (TEVAR) has allowed a minimally invasive approach for management of an array of thoracic aortic pathologies. Initially developed specifically for exclusion of thoracic aortic aneurysms, TEVAR is now used as an alternative to open surgery for a variety of disease pathologies due to the lower morbidity of this approach. Advances in endograft technology continue to broaden the applications of this technique.

Retrievable inferior vena cava filters can always be removed using "fall-back" techniques.

OBJECTIVE: Retrievable inferior vena cava filters (IVCFs) left in place for a prolonged period can lead to complications including filter migration, fracture, and caval thrombosis. "Fall-back" techniques for IVCF retrieval that can be used when standard snaring is unsuccessful have been recently described. The purpose of this study was to analyze how incorporation of these new techniques affected the outcomes of IVCF retrievals at our institution during the past 5 years. METHODS: Data were collected of all patients undergoing IVCF removal by vascular surgeons at a tertiary academic medical center between 2009 and 2013, including demographics and procedural and filter characteristics. A standard technique of snaring the retrieval hook was attempted first in all cases; if this was unsuccessful, a number of fall-back techniques were employed, including the use of endoscopic graspers, 18F sheaths, and snaring a second wire below the collar of the filter to collapse it into the sheath. RESULTS: IVCF retrieval was attempted in 275 patients; 3 were excluded intraoperatively because of thrombus in the filter. Most filters (97%) were Günther Tulips (Cook Medical, Bloomington, Ind); 70% had been placed prophylactically before bariatric surgery. A total of 268 filters (98.5%) were retrieved successfully, 213 (79%) by standard snaring and 55 (21%) with fall-back techniques. In patients undergoing fall-back techniques, technical success was achieved 100% of the time. The median time since insertion was significantly longer in the fall-back group (173 days vs 83 days; P < .0001). Four intraoperative complications occurred; fractured wires embolized to the right atrium or pulmonary artery and were successfully removed endovascularly. The majority of the procedures (80%) were performed under sedation in both groups. CONCLUSIONS: Incorporation of fall-back techniques may allow 100% technically successful and safe removal of retrievable IVCFs and is especially useful in removing filters with prolonged dwell time.

Upper extremity access for fenestrated endovascular aortic aneurysm repair is not associated with increased morbidity.

OBJECTIVE: Fenestrated endovascular aortic aneurysm repair (FEVAR) is an alternative to open repair in patients with complex abdominal aortic aneurysms who are neither fit nor suitable for standard open or endovascular repair. Chimney and snorkel grafts are other endovascular alternatives but frequently require bilateral upper extremity access that has been associated with a 3% to 10% risk of stroke. However, upper extremity access is also frequently required for FEVAR because of the caudal orientation of the visceral vessels. The purpose of this study was to assess the use of upper extremity access for FEVAR and the associated morbidity. METHODS: During a 5-year period, 148 patients underwent FEVAR, and upper extremity access for FEVAR was used in 98 (66%). Outcomes were compared between those who underwent upper extremity access and those who underwent femoral access alone. The primary end point was a cerebrovascular accident or transient ischemic attack, and the secondary end point was local access site complications. The mean number of fenestrated vessels was 3.07 ± 0.81 (median, 3) for a total of 457 vessels stented. Percutaneous upper extremity access was used in 12 patients (12%) and open access in 86 (88%). All patients who required a sheath size >7F underwent high brachial open access, with the exception of one patient who underwent percutaneous axillary access with a 12F sheath. The mean sheath size was 10.59F ± 2.51F (median, 12F), which was advanced into the descending thoracic aorta, allowing multiple wire and catheter exchanges. RESULTS: One hemorrhagic stroke (one of 98 [1%]) occurred in the upper extremity access group, and one ischemic stroke (one of 54 [2%]) occurred in the femoral-only access group (P = .67). The stroke in the upper extremity access group occurred 5 days after FEVAR and was related to uncontrolled hypertension, whereas the stroke in the femoral group occurred on postoperative day 3. Neither patient had signs or symptoms of a stroke immediately after FEVAR. The right upper extremity was accessed six times without a stroke (0%) compared with the left being accessed 92 times with one stroke (1%; P = .8). Four patients (4%) had local complications related to upper extremity access. One (1%) required exploration for an expanding hematoma after manual compression for a 7F sheath, one (1%) required exploration for hematoma and neurologic symptoms after open access for a 12F sheath, and two patients (2%) with small hematomas did not require intervention. Two (two of 12 [17%]) of these complications were in the percutaneous access group, which were significantly more frequent than in the open group (two of 86 [2%]; P = .02). CONCLUSIONS: Upper extremity access appears to be a safe and feasible approach for patients undergoing FEVAR. Open exposure in the upper extremity may be safer than percutaneous access during FEVAR. Unlike chimney and snorkel grafts, upper extremity access during FEVAR is not associated with an increased risk of stroke, despite the need for multiple visceral vessel stenting.

The binding of phosphonic acids at aluminium oxide surfaces and correlation with passivation of aluminium flake.

Measurements of adsorption isotherms of a series of thirteen mono- and di-phosphonic acids have shown that these bind strongly to the surface of high surface area aluminium trihydroxide. The incorporation of such phosphonates into a suspension of aluminium flake in an aqueous medium, modelling the continuous phase of a water-based paint, greatly suppresses the evolution of hydrogen. Whilst strong binding of the phosphonate to aluminium oxides is an essential criterion for good passivation, other factors such as the hydrophobicity of the ligand are also important in suppressing hydrogen-evolution.

Modeling Surface Engineering: Use of Polymetallic Iron Cages and Computer Graphics To Understand the Mode of Action of a Corrosion Inhibitor.

Simple organic molecules can have many functions. The active ingredient in the corrosion inhibitor 3-(4-methylbenzoyl)propionate works because it addresses the metal sites of a surface through carboxylate groups, forms hydrogen bonds with surface hydroxide groups (see picture), and provides excellent surface coverage through efficient packing of substituted aromatic groups.

Host-Guest Interactions of Inorganic Phosphates with the Copper(II) Complexes of the Hexaaza Macrocyclic Ligand 3,6,9,17,20,23-Hexaazatricyclo[23.3.1.1(11,15)]triaconta-1(29),11(30),12,14,25,27-hexaene.

The host-guest interactions between ortho-, pyro-, and tripolyphosphate anions and the mono and dinuclear copper(II) complexes of the hexaaza macrocyclic ligand BMXD (3,6,9,17,20,23-hexaazatricyclo[23.3.1.1(11,15)]triaconta-1(29),11(30),12,14,25,27-hexaene) were investigated by potentiometric equilibrium methods. Ternary complexes are formed in aqueous solution as a result of coordinate bonding, hydrogen bond formation, and Coulombic attraction between the host and guest. Formation constants for all the species found are reported. The dinuclear copper(II) complexes of BMXD show strong selectivity for pyrophosphate ions in the presence of orthophosphate ions over the whole p[H] range; the pyrophosphate/tripolyphosphate selectivity is p[H] dependent. The dinuclear copper(II) complex of BMXD, (Cu(2)-BMXD)(SO(4))(2), crystallizes in the orthorhombic space group Pccn, with a = 15.73(2) Å, b = 20.27(1) Å, c = 9.045(5) Å, and Z = 4. The sulfate counterions are found to bridge the copper(II) ions in adjacent molecules leading to an extended polymeric structure.