Single Chimney Research Articles

Early multicentric outcomes of the on-label and CE-marked combination of the Endurant with the Radiant chimney graft for the chimney endovascular aortic repair (EnChEVAR): The LaMuR Registry.

The aim of this study was to evaluate the early results of the CE-marked standardized device combination consisting of Endurant and the Radiant chimney graft (En-ChEVAR) for the treatment of juxtarenal aortic aneurysms. We analyzed multicentric non-industry sponsored case series evaluating the EnChEVAR technique for patients treated between December 2022 and February 2024. Clinical, perioperative procedure-related and radiological data were collected. The primary outcome measure was the freedom of a type Ia gutter-related endoleak at postoperative computed tomography angiography (CTA). Secondary outcome measures included early type Ia endoleak-related reinterventions, target vessel complications including dissection or loss of target vessel, major adverse events, and mortality. Continuous variables were presented as median (interquartile range [IQR]) and categorical variables as count and percentage. Ten patients were included in the present study. Eight (80%) were males, in nine cases a single chimney was implanted, and the other one was a double chimney graft placement. The treated aneurysms had an infrarenal neck length of 3.4 (1.2) mm. The rate of main body oversizing was 30%. The new neck length after chimney graft placement was 18 (3) mm. The median procedural time was 130 (17) mm, contrast medium use was 109 (26) mL, radiation time was 45 (12) min. The technical success was 100%. No type Ia endoleak was detected at the postoperative CTA. There were no target vessel issues. No major adverse events or death were observed. First reported cohort of patients treated with EnChEVAR demonstrated reproducible clinical and procedural outcomes within the 3 vascular centers with total exclusion of the aneurysms, patent renal arteries, and no evidence of gutter-related type IA endoleak. Further evidence with larger sample size of treated patients and longer follow-up are needed.

The evidence of chimney grafts in treating aortic arch diseases

Abstract: Steep aortic arch (such as Type III arch) and small angle between the chimney artery and aortic arch are two anatomic conditions suitable for chimney grafts (CGs). The more the number of chimneys, the higher the incidence of endoleak and branch occlusion; thus, the triple-chimney technique should be avoided unless the lesion involves zone 0 and no other better option is available, or a pending rupture is present and requires emergent repair. For the oversize of multiple chimneys, we suggest that the aortic stent and chimney stent should be increased by 5%, respectively, on the basis of single chimney. Moreover, the direction of the chimney stent is decided by the relative position of the proximal tear in patients with dissection. When the tear is located in the anterior segment, the chimney graft should be deployed behind the aortic stent graft, close to the posterior wall of the thoracic aorta, and in front of the aortic stent grafts when the tear is located in the posterior segment. In conclusion, if the endoleak is small and the patient’s condition is stable with no obvious discomfort, for most of the patients, the endoleak will disappear spontaneously in the follow-up. If the endoleak is large, microcoil could be implanted through the narrow and long gap to block the endoleak under the guidance of ultrasound. CGs technique needs to be scrutinized continuously as new data emerge. Special configurations of aortic and chimney endograft need to be developed to better treat aortic pathologies involving supra-arch branches.

Cathedral of Power: Battersea Power Station in Dystopian Visual Culture

Cathedral of Power: Battersea Power Station in Dystopian Visual Culture

Outcomes of thoracic endovascular aortic repair with chimney technique for aortic arch diseases.

ObjectiveThis study aimed to summarize the long-term experience of using the chimney technique in thoracic endovascular aortic repair (TEVAR) for aortic arch diseases.MethodsFrom November 2007 to June 2021, a total of 345 consecutive patients (mean age 56 ± 11.3 years, range 28–83, 302 men) with aortic arch pathologies underwent TEVAR combined with chimney technique (cTEVAR). Their medical data and follow-up results were retrospectively reviewed and analyzed.ResultsAmong the 345 patients, 278 (80.6%) received single chimneys, 53 (15.4%) received double chimneys, 7 (2%) received triple chimneys, and 7 (2%) underwent cTEVAR accompanied by other techniques (two with extra-anatomical bypass, two with in situ fenestration, and three with physician modified fenestration). A total of 412 chimney stents were used, including 27 in the innominate artery (IA), 113 in the left common carotid artery, 270 in the left subclavian artery, and two in the aberrant right subclavian artery. Early type IA endoleaks were found in 38 (11%) patients, including 12 with the double or triple chimney technique. Early type II endoleak was found in nine (2.6%) patients. Early re-intervention occurred in two patients with double chimney technique, one for chimney stent migration and the other for compression of chimney stent. The 30-day mortality was 1.2% (4 in 345). During a mean follow-up of 42 ± 22 months (range 1–108 months), major stroke occurred in nine (2.6%) patients, chimney occlusion or stenosis occurred in six (1.7%), and retrograde type A aortic dissection occurred in four (1.2%). Fourteen (4.1%) patients received the secondary intervention. The all-cause mortality was 6.7% (23 in 345). Additionally, the total adverse event rate after cTEVAR was 13.9% (48 in 345).ConclusionTEVAR with chimney technique provides a minimally invasive alternative with good chimney graft patency and low postoperative mortality during follow-up. However, the double and triple chimney techniques should be used cautiously as they seem to have a higher risk for type IA endoleak and adverse events after the operation.

Chimney endovascular aneurysm repair (ChEVAR) for hostile neck complex aneurysm.

Recent guidelines recognize the role of chimney endovascular aneurysm repair (ChEVAR) in the treatment of complex aortic disorders. The optimal configuration and number of visceral vessels that can be incorporated is still controversial. We aim to review outcomes from a multi-institutional decade-long experience with ChEVAR. Patients undergoing ChEVAR with multiple (≥2) chimney branches were selected from a prospectively maintained database at the two academic university hospitals. All patients were poorly suited for fenestrated or branched endograft repair (F/BEVAR) and deemed poor-risk for open surgery. Forty-nine multiple ChEVAR were performed in 44 men and 5 women, with complete outcome data at a mean follow-up of 18months. Overall, 2 patients died during follow-up (4%) with no aneurysm-related mortality and two ruptures after ChEVAR (4.1%) due to a type Ib endoleak from iliac limb pullout and persistent gutter-flow, both repaired with endovascular means. No stroke or spinal cord ischemia was noted during the follow-up period. Reintervention was undertaken in eight patients (16.3%) with five reinterventions for persistent gutter-flow and four chimney graft-associated. Three-vessel ChEVAR was performed in 16 patients, with two-vessel ChEVAR in 33 patients for a total of 114 chimney branches (mean 2.3 chimneys per patient). There were 21 superior mesenteric artery (SMA), 45 right renal, 46 left renal artery (LRA), and two accessory LRA chimneys placed. Antegrade configuration of chimney branches was chosen in 43 patients (88%). There were no significant differences between three-vessel and two-vessel ChEVAR upon univariate analysis in aneurysm size (65.6 vs 60.5mm; p = 0.059), iliac diameter (7.3 vs 7.1mm; p = 0.85), or endograft oversizing (30 vs 32.5%; p = 0.43). Three-vessel ChEVAR was associated with a larger aneurysm neck diameter (28.4 vs 25.0mm; p = 0.021), shorter native infrarenal neck (0.5 vs 3.37mm; p = 0.002) as well as longer seal zone (36.33 vs 22.67mm; p = 0.005) compared with two-vessel ChEVAR. At follow-up, there were no significant differences in gutter area between three-vessel and two-vessel ChEVAR (18.9 vs 15.7mm3; p = 0.73) nor the rate of persistent gutter-flow (12.5 vs 9.1%; p = 0.71). Reintervention to multiple chimney grafts and for persistent gutter-flow is higher compared to single chimneys and demands close surveillance. However, based upon this combined transantlantic experience, we believe multiple ChEVAR provides a reasonable and safe option for complex aortic aneurysm repair when open or custom endografts are not available or indicated based on their Instructions For use, even when triple chimney grafts are required. The optimal configuration for multiple ChEVAR still warrants further study, although theoretical preliminary advantages may exist for a combination of antegrade and retrograde chimneys.

AERODYNAMICS AND HEAT EXCHANGE OF SINGLE END TUBE DURING EXTERNAL FLOW

In Ukraine, the safety of modern thermal power plants depends on the reliable operation of the equipment installed on them. Unfortunately, the technical condition of the chimneys is not properly maintained. Of course, the modernization of basic equipment (boilers, switching to another type of fuel) leads to a decrease in the temperature of the exhaust gases. An important aspect to maintain the condition of the chimneys is to maintain the moisture of the exhaust gases.
 An important feature of the external flow of chimneys are large Reynolds numbers Re = wd/n, which reach 106 and more. In the thermal calculation only the average heat transfer coefficient on the outer surface of the pipe is usually determined, and the features of aerodynamics and local heat transfer due to the conicity of the pipe are not taken into account.
 The work is devoted to the study of aerodynamics and heat transfer in the air flow of a single conical chimney. The method of computer modeling with numerical integration of equations of motion and energy was used in the research. At the first stage, the single pipe with the uniform flow profile is considered. Further, the influence of the surrounding infrastructure on the aerodynamics and heat transfer of a single conical tube is studied.
 The single conical vertical pipe with 40 m height, 1.7 m diameter at the base and 0.85 m in the mouth was used for the calculation. The computer model was calculated in the ANSYS2020-R1 program. The model is developed in a homogeneous area with the air environment. In order to obtain reliable results, the study was conducted to obtain the optimal set of the grid parameters for the heat transfer conditions. The grids with parameters that affect the distance of the first node from the cylinder wall (options a, b, c, d) and the rate of increase in the size of the elements as they move away from the area of interest (Growth rate GR) were studied. The type of the cylindrical pipe with constant diameter of 1.7 m has been chosen to analyze the sensitivity and to check the grid.
 The turbulence model has been choosen as the following: RNG k-ε model which is common for the tasks of this class, the Enhanced Wall Function, the solution algorithm for the connection of the velocity pressure in stable flows Simplex. It is determined that in case if the distance between the first node from the cylinder wall and the area of interest (Growth rate GR) is more than 8 mm, instability and deviation of the obtained data from the values of the average coefficient of more than 20% appears. As a result of the research, the parameter grid area matching to the “2d” option of table 1 has been selected, i.e.: GR = 1.1, h = 8 mm. In the study of aerodynamics and heat transfer, the conical tube is conventionally divided into 22 sections (with 1 m height each). The case of uniform flow velocity in front of the pipe has been considered.
 As seen, the maximum value of the heat transfer coefficient is in the Zone(21-22). The research shows that oncoming flow velocity of 25 m/s causes the average value of heat transfer coefficient of the conical pipe 62.5 W/m2K, and 61.1 W/m2K according to the known formula . This indicates a small effect of taper on the average heat transfer of the entire pipe.
 In the calculations, three types of surrounding areas are considered: A - open coasts of seas, lakes and reservoirs, rural areas, including buildings less than 10 m high; B - urban areas, forests and other areas, evenly covered with obstacles higher than 10 m; C - urban areas with dense buildings with buildings higher than 25 m. Thus, the wind speed profiles for different types of terrain are nonlinear.
 The wind speed profile in front of the pipe (type of terrain) has a significant effect on the heat transfer coefficient. This confirms the need to take into account the type of terrain and the velocity profile in front of the pipe for local heat transfer.

Coupled Basin and Hydro-Mechanical Modeling of Gas Chimney Formation: The SW Barents Sea

Gas chimneys are one of the most intriguing manifestations of the focused fluid flows in sedimentary basins. To predict natural and human-induced fluid leakage, it is essential to understand the mechanism of how fluid flow localizes into conductive chimneys and the chimney dynamics. This work predicts conditions and parameters for chimney formation in two fields in the SW Barents Sea, the Tornerose field and the Snøhvit field in the Hammerfest Basin. The work is based on two types of models, basin modeling and hydro-mechanical modeling of chimney formation. Multi-layer basin models were used to produce the initial conditions for the hydro-mechanical modeling of the relatively fast chimneys propagation process. Using hydro-mechanical models, we determined the thermal, structural, and petrophysical features of the gas chimney formation for the Tornerose field and the Snøhvit field. Our hydro-mechanical model treats the propagation of chimneys through lithological boundaries with strong contrasts. The model reproduces chimneys identified by seismic imaging without pre-defining their locations or geometry. The chimney locations were determined by the steepness of the interface between the reservoir and the caprock, the reservoir thickness, and the compaction length of the strata. We demonstrate that chimneys are highly-permeable leakage pathways. The width and propagation speed of a single chimney strongly depends on the viscosity and permeability of the rock. For the chimneys of the Snøhvit field, the predicted time of formation is about 13 to 40 years for an about 2 km high chimney.

Chimney Graft Technique Combined With Embolization for Treating Ruptured Aortic Arch Lesions.

Background: This study aimed to share the experience in applying the chimney graft technique combined with embolization for treating aortic arch rupture under emergency conditions and evaluating early-term results in these patients.Methods: This study retrospectively included patients with ruptured aortic arch lesions who received the chimney graft technique combined with embolization between March 2016 and March 2021. The primary endpoint was a technical success, deemed as successful stent graft deployment to the planned location, patency of the target branch vessel, and absence of significant type I endoleak. The secondary endpoint was clinical success defined with the size of false lumen in follow-up remaining unchanged or decreasing over time, 30-day mortality, complication, and primary patency of chimney graft.Results: This study included 12 patients (age, 61 ± 12 years; male, 83%). Five patients (42%) received single chimney, one patient (8%) received double chimney, and six patients (50%) received triple chimney. Intraoperative type I endoleak occurred in six patients (50%) who underwent endovascular embolization in the primary operation. Post-operative type I endoleak, evaluated by computed tomography angiography examination following the primary operation, occurred in seven patients (58%), including one patient who received endovascular embolization two times. All patients with post-operative type I endoleak were successfully re-treated using coil and Onyx glue within 1 week, and the median length of stay was 22 ± 11 days (range: 7–44 days). Overall technical success was 100%. Eleven patients had completed their follow-up (median, 12 months, range: 1–34 months), and one patient was out of contact. The 30-day mortality was 9% (1/11, post-operative death of a patient with cerebral hemorrhage). No major complications and no chimney compression, migration, occlusion, or stenosis were recorded during follow-up. Seven patients (58%) have ≥6 months of clinical follow-up time with appropriate imaging. In four (57%) of these patients, diameter stabilization was detected, whereas three (43%) experienced significant reduction (≥5 mm).Conclusion: The patients in this study had satisfactory early-term outcomes. The chimney graft technique combined with coil and Onyx glue embolization may be a safe and effective treatment for ruptured aortic arch lesions under emergency conditions.

The role of surgical and total endovascular techniques in the treatment of ruptured juxtarenal aortic aneurysms.

Background: Ruptured juxtarenal aortic aneurysms (RJAAA) represent a special challenge in clinical practice, but the evidence to guide therapeutic decision-making is scarce. The aim of this study was to present two different approaches, open surgical (OAR) and chimney endovascular repair (CHEVAR), for treating patients with RJAAA. Patients and methods: This retrospective two-center study included all patients per center undergoing OAR or CHEVAR for RJAAA between February 2008 and January 2020. Juxtarenal aortic aneurysms were defined as having an infrarenal neck of 2-5 mm, measured after three-dimensional reconstruction of the computed tomography angiography scan. Results: 12 OAR patients (10 male, median age 73 years [58-90 years]) and 6 CHEVAR patients (all male, median age 74 years [59-83 years]) were included. In the OAR group, the proximal aortic clamping was suprarenal in 7 and interrenal in 5 patients. Cold renal perfusion was used in 4 patients, in 2 with suprarenal aortic clamping and in 2 with interrenal aortic clamping. 3 CHEVAR patients received a single renal chimney, the other 3 received double renal chimneys. Technical success was 12/12 in the OAR group 5/6 in the CHEVAR group. In-hospital mortality and 30-day mortality were 3/12 after OAR and 0/6 after CHEVAR. 2 OAR patients required transient dialysis. Median in-hospital stay was 14 (10-63) and 8 (6-21) days and median follow-up (FU) was 20 (3-37) and 30 (7-101) months, respectively. No further deaths occurred during FU. One OAR patient and 4 CHEVAR patients required aortic reinterventions. Conclusions: RJAAAs are rare. Both OAR and CHEVAR can represent adequate treatments for RJAAAs. OAR is the traditional approach, but CHEVAR has - in a high-volume center - promising early results with nonetheless a need for continuous FU to prevent reinterventions. Defining the studied aortic pathology precisely is essential for future research in order to draw valid conclusions.

Computational studies on the airflow developed by the building-integrated passive solar energy system

Ventilation and cooling demand are expected to rise in the next decades. Sustainable standalone solar passive air ventilation technique could be one of the clean options. In this study, a building-integrated passive solar energy technology (BIPSET) consists solar photovoltaic (PV) and solar still, was implemented for attaining multiple outputs, such as air ventilation, power and clean water in a building prototype proposed based on Chief Minister's solar powered green house scheme, Government of India. Solar PV and solar still were connected separately with single chimney using necessary duct connections. The heat gain in the PV panels was used for air ventilation inside the building. Computational fluid dynamics analysis was carried out in SOLIDWORKS-2017 Flow simulation software to study the airflow behaviour, such as air change per hour, heat gain and efficiencies in the building-integrated system. The results are in good agreement with experimental values for both sunny and cloudy conditions. This solar still duct arrangement reduced the airflow inside the building in noon hours by 30%. However, it improved the airflow by 8% in the evening hours. The present system is in accordance with standards like ASHRAE 62.1–2010 and GRIHA, which indicates its commercial applicability. Moreover, the environment analysis indicates that the system offers CO2 savings of 17.5 kg/year by adopting passive air ventilation. A modified integrated system was proposed to utilize the heat energy from the solar still for air ventilation by altering the duct arrangements.

Infected Pseudoaneurysm of the Brachiocephalic Artery after 2-Debranching+Single Chimney TEVAR Successfully Treated with a Double D Technique Using VIABAHN Endoprosthesis

Infected Pseudoaneurysm of the Brachiocephalic Artery after 2-Debranching+Single Chimney TEVAR Successfully Treated with a Double D Technique Using VIABAHN Endoprosthesis

Changing Brine Inputs Into Hydrothermal Fluids: Southern Cleft Segment, Juan de Fuca Ridge

AbstractIn 2016, temperature recorders were recovered, temperatures were measured, and fluid samples were collected from Vent 1, a high temperature (338°C) hydrothermal discharge site on the southern Cleft Segment of the Juan de Fuca Ridge. Coupled with previous sampling efforts, this collection represents a 32‐year record of discharge from a single chimney structure, the longest record to date. Remarkably, the fluid has remained brine‐dominated for more than three decades. This brine formed during phase separation and segregation prior to initial observations in 1984. Although the chloride concentration of the discharging fluid has decreased with time, the fluid temperature has remained nearly constant for at least 3.3 years and probably for 15 or even 22 years. Compositions of the discharging fluids are consistent with inputs from a deep‐sourced brine, which was last equilibrated at >400°C at a depth consistent with the base of the sheeted dikes and the brittle‐ductile transition. This brine mixed (diffusion or dispersion) with a likely non‐phase‐separated, hydrothermal fluid prior to discharge. A survey of hydrothermal endmember fluids with chlorinities in excess of 700 mmol/kg shows, with the exception of Fe, a single trend between major ion concentrations and chlorinity even though data are from a range of crustal compositions, spreading rates, and water and magma depths. Calculated deep‐sourced brines from hydrothermal fluid data are similar to data based on fluid inclusions and estimates of brine assimilation in magmas. A better understanding of brines is required given their potential duration of discharge and capacity for mobilizing metals.

Аналіз екологічної ефективності димових труб котелень за умов застосування теплоутилізаційних технологій

Виконано аналіз екологічної ефективності димових труб газоспоживальних котелень комунальної теплоенергетики за умов застосування сучасних теплоутилізаційних технологій з охолодженням відхідних димових газів нижче від температури роси водяної пари, що міститься в газах. У цих технологіях використовували теплоутилізатори, призначені для нагрівання зворотної тепломережної води котельні, та тепловий метод антикорозійного захисту газовідвідних трактів шляхом байпасування частини гарячих газів від котла повз зазначене теплоутилізаційне устаткування. Розглянуто одиночні димові труби різного типу під час виготовлення корпусу труби з антикорозійного матеріалу або під час монтування в цегляну (або іншу трубу з покращеними теплоізоляційними властивостями) газовідвідних стволів з цих матеріалів. Доліджено показники максимальних приземних концентрацій у навколишньому середовищі труби найшкідливіших викидів димових газів, таких як окиси вуглецю СО і азоту NOх залежно від режиму роботи котлів згідно з тепломережним графіком роботи котельні. Проаналізовано вплив використання теплоутилізаційних технологій та зазначеного теплового методу захисту димових труб на безпеку експлуатації газовідвідних трактів і на умови розсіювання шкідливих викидів. Показано, що в разі дотримання рекомендованих режимів роботи котлів зі зменшенням їх кількості згідно з тепломережним графіком роботи котельні й в разі застосування сучасних теплоутилізаційних технологій та димових труб з антикорозійних матеріалів реалізується розсіювання викидів СО та NOх у навколишньому середовищі згідно зі сучасними нормативними вимогами.

Chimney Endovascular Aneurysm Repair from Below

Chimney endovascular aneurysm repair (ChEVAR) is able to repair a juxtarenal abdominal aortic aneurysm (JRAAA) when open or fenestrated/branched repair are not possible. For placement of the chimney graft(s) upper extremity access is necessary, however, not all patients have a suitable aortic arch anatomy for this. A successful ChEVAR is described with a single chimney graft placed from femoral access using steerable sheath technology.

Endovascular treatment for aortic arch pathologies: chimney, on-the-table fenestration, and in-situ fenestration techniques.

BackgroundRevascularization of the supra-aortic major branches in thoracic endovascular aortic repair (TEVAR) is challenging owing to the complex anatomic configuration of aortic arch pathologies. This study aims to evaluate the feasibility, effectiveness, and safety of three major techniques—chimney, fenestrated, and in-situ fenestration—for patients with aortic arch pathologies.MethodsA retrospective analysis was performed involving 234 patients with aortic arch lesions, who underwent TEVAR with adaptations in technique (chimney, fenestrated, or in-situ fenestration) between January 2016 and December 2017.ResultsOne hundred and twenty-six patients underwent the chimney technique (98 single chimneys, 24 double chimneys, and four triple chimneys); one hundred and two patients (102/234) were treated with on-the-table fenestration technique (92 single fenestrations, nine double fenestrations, and one double fenestration plus innominate artery chimney); and the remaining six patients underwent in-situ needle fenestration technique. Overall, indications included aortic dissections (99/234), aortic arch aneurysms (60/234), penetrating aortic ulcers (72/234), and re-interventions (3/234). The technical success rates were 99.6%. There were five cases of early all-cause mortality. The patency rates of overall branches were 99.6%. There were 15 cases with type Ia endoleak—14 in the chimney group (11.1%) and one in the on-the-table fenestration group (1%). Five patients underwent re-interventions. The median follow-up time for all patients was 28 (range, 16–41) months.ConclusionsOur experience suggests that chimney, on-the-table fenestration, and in-situ needle fenestration techniques are feasible, effective, and safe treatment options for aortic arch pathologies with encouraging mid-term results. Long-term durability concerns require further evaluation.

Outcomes of Chimney Thoracic Endovascular Aortic Repair for an Aortic Arch Aneurysm

Chimney thoracic endovascular aneurysm repair (TEVAR) has advantages that include no requirements for special devices; however, problems have been identified such as gutter leaks. The aim of this study is to evaluate the short- and mid-term results of TEVAR with chimney technique including the safety, efficacy, and risk factors for occurrence of gutter endoleak in this technique. A retrospective single-center study was conducted on 55 consecutive patients who underwent first-time chimney TEVAR for arch aneurysms in the past 7years. This consisted of 33 cases of single-chimney (SC) TEVAR and 22 cases of double-chimney (DC) TEVAR. The outcomes of these 55 cases of SC-TEVAR and DC-TEVAR were retrospectively examined. Risk factors for endoleaks in chimney TEVAR were also examined. Operative mortalities of 3.0% and 4.5% were observed in SC-TEVAR and DC-TEVAR, respectively. Incidences of stroke were 12.1% in the SC-TEVAR and 4.5% in the DC-TEVAR, resulting in endoleaks in 16 patients (48.5%) in SC-TEVAR and 6 patients (27.3%) in DC-TEVAR. Only 1 of the 77 chimney grafts was occluded, with a patency rate of 98.7%. SC-TEVAR and small distance from the common carotid artery were the risk factors of type I endoleaks. Overall survival rates over a period of 1, 3, and 5years were 82.3%, 78.0%, and 57.7%, respectively, in the SC-TEVAR group and 95.2%, 89.3%, and 76.5%, respectively, in the DC-TEVAR group. Freedom from aneurysm-related death over 1, 3, and 5years was 82.3%, 69.0%, and 57.7%, respectively, in the SC-TEVAR group and 95.2%, 89.3%, and 89.3% in the DC-TEVAR group. Freedom from secondary intervention over 1, 3, and 5years was 80.2%, 64.7%, and 47.2%, respectively, in the SC-TEVAR group and 95.0%, 74.0%, and 74.0%, respectively, in the DC-TEVAR group. The short- and mid-term results of chimney TEVAR were worse than expectation. Especially, the results of SC-TEVAR were not acceptable because of extremely high incidence of type I endoleak and high incidence of stroke.

Outcomes of the Chimney Technique for Endovascular Repair of Aortic Dissection Involving the Arch Branches

The results of different chimney techniques in different zones of aortic arch were analyzed, so as to provide clues to decrease the complications of chimney thoracic endovascular repair (cTEVAR). Between April 2012 and April 2017, 234 patients with aortic dissection involving arch branches received cTEVAR. Among these patients, 156 (66.7%) received single chimney (SC), 48 (20.5%) received double chimneys (DCs), and 30 (12.8%) received triple chimneys (TCs). A total of 342 chimney grafts (CGs) were used. All chimney grafts were successfully implanted, and no migration or occlusion was observed during follow-up. Mortality of this cohort was 1.7% (4/234). Three (3/234, 1.3%) patients suffered from cerebral vascular events. Seventy-five (75/234, 32.1%) had intraoperative type I endoleak. Twenty-seven (27/75, 36.0%) of them were found to have automatically disappeared in the follow-up period. The false lumens of 33 (33/75, 44.0%) were found to be stable, and 15 (15/75, 20%) were found to have expanded and were successfully retreated by endoleak embolization. The proximal tear located in zone 0 had higher instant endoleak rate than zone 1, zone 2, and zone 3 (P=0.041; P=0.042; P=0.009). TC were found to have more instant endoleak than SC (P<0.001) and DC (P=0.012). But in the follow-up period, there was no significant difference. TCs and the proximal tear locating in zone 0 were found to be with higher instant endoleak rate, and it may need more rigorous follow-up. Some of the endoleak after cTEVAR could automatically disappear and some could be completely re-treated by gutter embolization procedure.

Collected Transatlantic Experience From the PERICLES Registry: Use of Chimney Grafts to Treat Post-EVAR Type Ia Endoleaks Shows Good Midterm Results

Purpose: The aim of this retrospective analysis was to evaluate the performance of the chimney (ch) technique in the treatment of type Ia endoleaks after standard endovascular aneurysm repair (EVAR). Methods: Between January 2008 and December 2014, 517 chEVAR procedures were performed in 13 US and European vascular centers (PERICLES registry). Thirty-nine patients (mean age 76.9±7.1 years; 33 men) were treated for persistent type Ia endoleak and had computed tomography angiography or magnetic resonance angiography follow-up at >1 month. Endurant abdominal stent-grafts were used in the 20 cases. Single chimney graft placement was performed in 18 (46%) patients and multiple in 21 (54%). Overall, 70 visceral vessels were targeted for revascularization. Results: Technical success was achieved in 35 (89.7%) cases; 3 persistent type Ia endoleaks and 1 chimney graft occlusion were detected within the first 30 days. Thirty-day mortality was 2.6%. Two other deaths (not aneurysm related) occurred during a mean follow-up of 21.9 months (0.23–71.3). Primary patency of the chimney grafts was 94.3% at 36 months. In a subgroup analysis comparing Endurant to other stent-grafts, no significant differences were observed regarding persistent endoleak [1/20 (5%) vs 2/19 (11%), p=0.6] or reintervention [1/20 (5%) vs 0/19 (0%)]. Conclusion: The present series demonstrates that chEVAR in the treatment of post-EVAR type Ia endoleaks has satisfactory results independent of the abdominal and chimney graft combinations. Midterm results show that chEVAR is an effective method for treating type Ia endoleaks.

Redox changes in a seafloor hydrothermal system recorded in hematite-chalcopyrite chimneys

Hydrothermal chimneys composed of hematite and chalcopyrite grow at the Irina II vent site (Logatchev hydrothermal field, Mid-Atlantic Ridge). Hematite and chalcopyrite form layers that repeatedly alternate within the chimney wall. The repeating alternation of hematite and chalcopyrite implies for repeating changes in the physico-chemical parameters of the vent fluid. The modeled stability diagrams of hematite and chalcopyrite at the physico-chemical conditions of the Irina II hydrothermal site showed that the precipitation of these two Fe-minerals is primarily governed by the activity of H2S and pH. Fe-isotope studies suggest that the successive deposition of chalcopyrite (δ56/54Fe = ~0.20‰) and hematite (δ56/54Fe = ~0.60‰) layers in the Irina II chimneys is a result of redox changes in the hydrothermal fluid. The replacement of hematite by either magnetite or chalcopyrite at some places also suggests for a redox inversion in the hydrothermal system from oxic to reduced. Chondrite-normalized rare earth element distribution patterns of the hematite layers show a strong negative Eu anomaly, which is interpreted to be a result of crystal-chemical control on the rare earth element fractionation during hematite precipitation. Sr isotope systematics indicate significant and variable incorporation of seawater (from ~40% to ~80%) in the hydrothermal system. Nd-Pb-isotope studies show that Nd and Pb in chalcopyrite and hematite layers are derived mainly from the underlying mafic and ultramafic rocks. The chimneys are young (5.13 ± 1.28 kyrs B.P.) and their wall thickened inward. The duration of redox cycles (oxic and reducing) within the scale of a single chimney is about several hundred years. The hematite layers are enriched in W, In, Sn and U indicating that primary hematite hydrothermal deposits at the seafloor may be a potential source for these strategic trace elements. High concentrations of these elements in the studied hematite layers can be explained by their (easy) ion substitution for Fe3+ in the hematite crystal lattice. Whereas the most plausible source of the elevated W, In and Sn contents are the hydrothermal fluids, the seawater is the possible major source of U.

Love &amp; Hypothermia

Love & Hypothermia Laura Paul Watson (bio) Keywords Love, Hypothermia, Poetry, Laura Paul Watson, heart First, it will feel like surprise. Like the edge of something unconsidered: a glass let go; an open palm; how cold a mouth can be and still say love, still say okay. Shore is a hundred yards away, maybe two, and on its edge a thousand stones will watch us work and stall in the water. This is when the vessels narrow in our hands, when the blood retreats and pauses in the heart. This is when, across the bay, a single chimney will rise from a single house. In its hearth, a fire. The water, we will say, is a slow hand closing. A clouded stone. The cloudless sky, a cruel cliché. What is left for us to say? By the time we land in the aluminum heart of the boat, we are mackerel-blue, stupid, and something in each of us has opened to the other. [End Page 383] Laura Paul Watson laura paul watson lives and writes in Pine, CO. She is a graduate of the MFA program at the University of Florida. When not writing poetry, she works as a general contractor remodeling and building new homes in the Denver area. Her work has also appeared in the Cincinnati Review, Poetry Northwest, and Meridian, among others. Copyright © 2017 The Massachusetts Review, Inc