Long-term outcomes of chimney endovascular aneurysm repair procedure for complex abdominal aortic pathologies

OBJECTIVE

The aim of this study was to update our earlier experience and to evaluate long-term outcomes of chimney endovascular aortic repair performed for selected cases with complex abdominal aortic aneurysm.

METHODS

A single-center retrospective cohort study was conducted on 51 consecutive patients who underwent chimney endovascular aortic repair procedure, deemed unfit for open surgical repair and fenestrated endovascular aneurysm repair, from October 2009 to November 2019. Kaplan-Meier analyses were used to assess the estimated overall survival, freedom from aneurysm related mortality, freedom from reintervention, freedom from target vessel instability, and freedom from type Ia endoleaks.

RESULTS

Fifty-one patients (mean age, 77.1 ± 7.5 years) with a mean preoperative maximum aneurysm diameter of 74.2 ± 20.1 mm were included. Mean follow-up duration was 48.6 months (range, 0-136 months). Estimated overall survival at 5 and 7 years was 36.3% ± 7.1% and 18.3% ± 6.0%, respectively. Freedom from aneurysm-related mortality was 88.6% ± 4.9% at 7 years. Estimated freedom from type Ia endoleaks at 7 years was 91.9% ± 3.9%. A total of 21 late reinterventions were performed in 17 patients (33%). Most of them were performed to treat type II endoleaks with sac growth (47.6%; n = 10) and type Ib endoleak (23.8%; n = 5). Estimated freedom from reintervention at 7 years was 56.3% ± 7.9%. Estimated freedom from target vessel instability at 7 years was 91.5% ± 4.1%.

CONCLUSIONS

The 7-year results of chimney endovascular aortic repair procedures performed in our center confirm the long-term safety and effectiveness of this technique in a series of high-risk patients with large aneurysms. The present study has, to the best of our knowledge, the longest follow-up for patients treated with chimney endovascular aortic repair, and it provides data to the scarce literature on the long-term outcomes of this procedure, showing acceptable to good long-term results.

Left carotid chimney and left subclavian artery laser fenestration for zone 1 thoracic endovascular aortic repair

Thoracic endovascular aortic repair has become an increasingly used option for treatment of descending thoracic aortic aneurysms and dissections. Pathology involving the proximal thoracic aorta is more complex and requires revascularization of the subclavian and carotid arteries. We report a case of an arch thoracic aortic pseudoaneurysm repaired via a complete endovascular approach using a left carotid chimney and left subclavian artery laser fenestration.

Trans-subclavian approach for Impella CP implantation using the chimney graft in a pediatric patient with fulminant myocarditis during extracorporeal support

Impella is a device effective for the treatment of cardiogenic shock. However, among small children, its application has limitations due to left ventricle size and vasculature and the turning diameter of the aortic arch. Herein, we report an 11-year-old girl with fulminant myocarditis who was successfully managed with Impella CP implantation via the right subclavian artery using a polyethylene terephthalate chimney graft. Compared with insertion via the femoral artery, this method has several advantages. That is, it can address limitations in aortic arch diameter and facilitate equable fixation of the Impella device in small pediatric patients.

Chimney endovascular aneurysm repair-induced mesenteric ischemia: a report of an extremely rare complication

The chimney endovascular aneurysm repair (Ch-EVAR) technique has progressively increased in popularity in the treatment of complex aortic aneurysms. However, the long-term results of this technique still must be assessed, especially in comparison to custom-made solutions. The patency of chimney grafts has always been one of the important issues with the Ch-EVAR technique. However, interactions between nonstented aortic side branches and chimney stent grafts have rarely been discussed. In the present case report, we describe a rare case of mesenteric ischemia due to superior mesenteric artery ostium coverage by the misalignment of a renal stent graft in a Ch-EVAR.

Functional evaluation of a spiral neobladder with an angled chimney; A prospective randomized comparative study

OBJECTIVES

to assess the functional outcome of performing ureteric re-implantation to an angled short chimney in a modified spiral orthotopic ileal neobladder.

PATIENTS AND METHODS

From January 2018 to December 2020, 90 male patients with bladder cancer underwent radical cystectomy and spiral ileal neobladder reconstruction with a chimney. Patients were randomly divided in two groups according to the position of the chimney [straight and angled] to which the ureters will be implanted. Postoperative evaluation included clinical, laboratory, radiographic and urodynamic studies.

RESULTS

There were no perioperative deaths. The mean operative time for the procedure was 4.7 ± 1.2 h in group I and 4.9 ± 1.3 h in group II (p 0.456). No intraoperative complications occurred. Early postoperative complications occurred in 8 patients. In group I, according to the modified Clavien system, GII complication occurred in 2 (5%) patients in the form of DVT in 1 (2.5%) and surgical site infection in 1 (2.5%). GIIIa occurred in 3 (7.5%) patients in the form of wound dehiscence. In group II, GII occurred in 2 (4.8%) patients in the form of prolonged urinary leakage and myocardial infarction, each occurred in one patient. GIIIb occurred in 1 (2.4%) patient in the form of intestinal leak. Poucho-ureteral reflux occurred in 10 patients [3 (7.5%) in group I and 7 (16.8%) in group II (p 0.001)].

CONCLUSIONS

The preliminary results of the right sided angled chimney during neobladder reconstruction are safe, acceptable, without an extra time to develop an anti-reflux technique and without an increased incidence of reflux.

Study of the performance of thermoelectric generator for waste heat recovery from chimney: impact of nanofluid-microchannel cooling system

A huge number of chimneys all over the world utilized in many industrial applications and applications like restaurants, homes, etc. contribute badly on the global warming and climate change due to their waste heat. So, in this paper, the performance of thermoelectric generator (TEG) cooled by microchannel heat spreader having nanofluid and used for waste heat recovery from vertical chimney is investigated. Using heat spreader with microchannel cooling system increases the output TEG power compared to natural convection cooling system. In this paper, the impact of microchannel sizes, using nanofluid and heat spreader with different sizes on the TEG performance and cooling, is considered. Three-dimensional mathematical models including TEG, microchannel, nanofluid, and heat spreader are presented and solved by Ansys Fluent software utilizing user-defined memory, user-defined function, and user-defined scalar. All TEG effects (Joule, Seebeck, and Thomson) are considered in TEG model. Results indicate that TEG power rises with increasing the heat spreader and microchannel sizes together. Increasing microchannel and heat spreader sizes four times of TEG size raises the TEG output power by 10%. This also achieves the maximum cooling system efficiency of 88.9% and the maximum net output power. Microchannel heat spreader cooling system raises the system (TEG power-pumping power) net power by 125.2% compared to the normal channel and decreases the required cooling fluid flow rate. Utilizing copper-water and Al₂O₃-water nanofluids rises maximally the TEG output power by 14% and 4%, respectively; however, it increases the pumping power. Moreover, using nanofluids increases the net output power at low Reynolds number and decreases it at higher Reynolds number.

Endovascular repair of abdominal and thoracoabdominal aneurysms using chimneys and periscopes is associated with poor outcomes

OBJECTIVE

Chimneys and periscopes are often used to treat pararenal or thoracoabdominal aneurysms de novo or after failed open or endovascular repair. We sought to describe our institutional experience, given their limited success and questionable long-term outcomes.

METHODS

We retrospectively reviewed the electronic records for patients treated with chimneys/periscopes from 1997 through 2020. Baseline characteristics, procedural details, periprocedural complications, reinterventions, and midterm outcomes were collected.

RESULTS

Fifty-eight patients (86 vessels) were treated; the median follow-up was 32 months (range, 0.03-104 months). There were 36% (n = 21) juxta-renal, 2% (n = 1) para-visceral, and 21% (n = 12) thoracoabdominal aneurysms, and 41% (n = 24) had pararenal failure of prior endovascular aneurysm repair (n = 17) or open repair (n = 7). Stent configuration for the majority of the 86 vessels (n = 80; 93%) treated were chimney configuration (n = 6 periscopes; 7%). The most common stent graft utilized was Viabahn, and 8.1% (n = 7) were reinforced with a bare metal stent. Although the majority of the cases were elective, 36.2% (n = 21) of the cases were urgent/emergent. At the conclusion of the initial procedure, 16 of 58 patients had an endoleak (gutter, 50% [8/16]; type Ia, 25% [4/16]; and type II, 25% [4/16]). On follow-up, 14 of 58 patients developed one or more endoleaks, with the most common endoleaks being a gutter endoleak (35% [7/20]). Other endoleaks observed included 30% (6/20) type III, 15% (3/20) type Ia, 15% (3/20) type Ib, and 5% (1/20) type II. Eleven of 58 patients underwent interventions for one or more endoleak (gutter, 33% [5/15]; type Ib, 20% [3/15]; type II, 7% [1/15]; and type III, 40% [6/15]). Twelve of 58 patients returned to the operating room for one or more procedures during the index hospitalization (five laparotomies, three dialysis access, three acute limb ischemia, and four chimney/periscope interventions). Ten of 58 patients underwent angioplasty/stenting for chimney/periscope compression or occlusion during the follow-up period. Survival was 61.3% at 1 year by Kaplan-Meier analysis (75% for elective, 37% for urgent/emergent) (aneurysm-related death, 22%). Cox hazard modeling showed that aneurysm diameter (hazard ratio, 1.03; 95% confidence interval, 1.004-1.05; P = .02) and urgent/emergent interventions (hazard ratio, 3.6; 95% confidence interval, 1.33-9.74; P = .01) were predictors of mortality.

CONCLUSIONS

Endovascular repair of aortic aneurysms with chimneys/periscopes is associated with poor outcomes, including limited technical success and aneurysm exclusion, as well as high morbidity and mortality, with a high rate of reinterventions both in the immediate postoperative period and on follow-up. They should be used only when other surgical or endovascular options are not possible.

[Endovascular aortic repair: the hostile aneurysm neck : Morphologic definition, impact on long-term outcome, and treatment options]

DEFINITION

A hostile neck is defined by various anatomical conditions that describe a morphology of the proximal aneurysmal neck of infrarenal aortic aneurysms that is unfavorable for endovascular treatment (endovascular aortic repair, EVAR): proximal landing zone length ≤ 15 mm, angulation of the aortic neck > 60°, conical aortic neck, diameter of the aortic neck > 32 mm, and circumferential calcification/thrombus.

EFFECTS ON OUTCOME

These morphological parameters are not only associated with a higher perioperative technical failure rate (primary type 1 endoleak) but also with poorer long-term results (secondary type 1 endoleak) and thus a higher reintervention rate in standard EVAR, so that standard EVAR should be reserved for a few exceptions in these cases.

TREATMENT OPTIONS

Due to the rapid development of endovascular techniques in the last decade, we now have a variety of endovascular options for aneurysms with hostile necks, for both elective treatment and emergency care, in addition to conventional open surgery, which is still the standard method in many cases and is currently undergoing a renaissance: fenestrated endovascular aortic repair (FEVAR) as the method of first choice in the elective setting, EVAR with chimneys (ChEVAR), endosuture aneurysm repair (ESAR). An important option is the conservative approach, which can be a reasonable choice if the patient's preference is taken into account and a careful risk-benefit assessment is performed.

Physician-Modified Endografts Versus Chimney/Snorkel for Ruptured and Symptomatic Juxtarenal and Paravisceral Aneurysms in the Vascular Quality Initiative

OBJECTIVES

Ruptured and symptomatic juxtarenal and paravisceral aneurysms present technical challenges during endovascular repair. We sought to compare physician modification and fenestrated (PMEG) versus chimney/periscope/snorkel (CHIMPS) repair techniques for the treatment of ruptured and symptomatic paravisceral and juxtarenal aortic aneurysms (r/sPJAA).

METHODS

Patients in the thoracic and complex endovascular aneurysm module of the Vascular Quality Initiative (VQI) national registry undergoing CHIMPS and PMEG for r/sPJAA were included. Patients who underwent thoracic aneurysm repair with only celiac intervention or who had coverage or occlusion only of one renal or visceral branch vessel were excluded. One-year mortality was the primary outcome. Secondary outcomes included peri- and postoperative endoleak, hospital and ICU length of stay, reintervention, and other local and systemic complications.

RESULTS

A total of 81 CHIMPS and 47 PMEG patients were identified. Patients undergoing PMEG were more frequently symptomatic, had a history of CHF and were taking aspirin, statin and P2Y12 antiplatelet medications. Patients undergoing CHIMPS presented more frequently with rupture. There was no significant survival advantage for CHIMPS over PMEG patients (P = 0.5). There were no apparent long-term differences in the numbers of endoleaks or in the rates of subsequent reinterventions between the two groups.

CONCLUSIONS

It does not appear that the procedure type (CHIMPS versus PMEG) is associated with postoperative survival in patients with r/sPJAA. Not surprisingly, survival is associated with postoperative complications, particularly myocardial infarction and intestinal ischemia. Further research should evaluate reasons for failure to rescue from and the impact of postoperative complications on the postoperative survival after endovascular repair of r/sPJAA.

Enhancement of the daily performance of solar still by exhaust gases under hot and cold climate conditions

A study is presented on the enhancement of solar still (SS) performance by using chimney exhaust gases (EGs) passing through chimney channels under the still basin. The impact of the exhaust gas temperature on the SS temperature, productivity, efficiency, and freshwater yield cost is considered. The SS performance with the chimney is compared with that of conventional solar still. The study is performed under the hot and cold climate conditions of Upper Egypt. A complete transient mathematical model of the physical model including the solar still regions temperatures, yield, and heat transfer between the SS and the EGs is constructed. This model is solved by using Runge-Kutta method of fourth-order and programmed inside MATLAB software and validated using an experimental setup. The results show that the SS saline water temperature and freshwater yield rise with rising EGs temperatures. Furthermore, the impact of using EGs on the SS performance in winter is superior to that in summer, and also during the daytime is higher than that of night. Using chimney EGs at 75 °C and 125 °C enhances the daily freshwater yield of the SS by more than three times and about six times in winter, respectively, and about two and half times and more than three times in summer, respectively. Using EGs at 125 °C achieves a maximum solar still efficiency of 29.5% in winter and 49.5% in summer with an increase of 41% and 55.7%, respectively, and reduces its yield cost by 63.6% compared to conventional SS.

Comprehensive analysis and investigation of accident/occupational disease responsibility rates: A case study for accidental CO poisoning

One of the major problems of courts and insurance companies is the lack of a proper technique to determine the rate of responsibility of the parties involved in the accident. The aim of this study was to determine the Accident/Occupational Diseases Responsibility Rates (AOD RR) for complex events. Accordingly, a case study of a complex accident of carbon monoxide (CO) poisoning was selected and Occupational Accident Tree Analysis (OATA) and Occupational Accident Component Analysis (OACA) techniques, which were solely used to investigate occupational accidents, were used with the new names Accident/Occupational Disease Tree Analysis (AOD TA) and Accident/Occupational Disease Component Analysis (AOD CA) to evaluate their applicability to investigate non-occupational accidents and occupational diseases. For this purpose, causes of CO penetration to victims' room was assessed using gas tracking methods. Finally, Fuzzy Accident/Occupational Disease Tree/Component Analysis (FAOD TA and FAOD CA) techniques were developed and used for determining AOD RR in fuzzy environment. The results showed that the AOD RR obtained by AOD TA and AOD CA based on the average of experts' personal opinions and consensus between experts, and AOD TA and AOD CA in a fuzzy environment were close to each other, with the power terminal and the power cable crossing route being the main routes of transmission and penetration of CO to the victims' room. Also, the owner, contractor, tenant, and serviceman were responsible for the CO poisoning of victims. It can be concluded that any hole, crack, or fission in the building can result in CO penetration to the individuals' living rooms, and gas tracking in early winter, especially in older buildings, plays a very significant role in preventing residents' poisoning. Further, due to the uncertainty of AOD TA and AOD CA techniques, it is recommended to use FAOD TA and FAOD CA techniques for increasing the accuracy of the results. This will enhance the court and insurance companies' trust in the opinions of accident investigation experts, decrease delays in the proceedings, and prevent any violation of the individual rights.

Emergent percutaneous chimney endovascular aortic repair of a secondary aortoenteric fistula in the setting of a solitary kidney

Secondary aortoenteric fistula is a potentially lethal complication after aortic surgery. Traditional treatment consists of open graft excision with extra-anatomic bypass or in situ reconstruction. Patients who present in extremis, however, are generally poor candidates for re-do open aortic surgery. Endovascular repair has emerged as an alternative treatment modality for patients who would otherwise be unable to tolerate an extended operation. We report here a case of urgent endovascular repair of a juxtarenal secondary aortoenteric fistula via endovascular aneurysm repair with a renal artery chimney in a patient with a solitary kidney who presented in hemorrhagic and septic shock.

The PROTAGORAS 2.0 Study to Identify Sizing and Planning Predictors for Optimal Outcomes in Abdominal Chimney Endovascular Procedures

OBJECTIVE

The aim was to identify predictors of adequate pre-operative sizing and planning for chimney endovascular aortic repair (ChEVAR) in order to reduce the incidence of persistent type Ia endoleaks (IaELs) without influencing chimney graft (CG) patency.

METHODS

Consecutive patients who underwent ChEVAR between January 2009 and December 2017 at a single centre were evaluated retrospectively. Included were patients treated with one device combination (Medtronic Endurant mated with Getinge Advanta V12/iCast) and placement of single or double CG. The freedom from IaEL related re-interventions and primary CG patency was estimated by measuring aortic stent graft oversizing (OS), total neck length (TNL), and a composite parameter (L-OS: TNL [mm] + OS [%]).

RESULTS

Seventy-three patients who underwent placement of 101 CGs (45 single, 28 double) met the inclusion criteria. The median radiological follow up was 25.5 (interquartile range [IQR] 12-48) months. Freedom from IaEL related re-intervention was achieved in 94.6% with a median OS of 38.5% (IQR 30%-44%, p = .004), TNL 19 mm (16-25 mm, p = .62), and L-OS 59 (51-65, p = .018). Primary CG patency was achieved in 95% of the cases with a median OS of 36% (29%-42%, p = .008), TNL 19 mm (15.5-26 mm, p = .91), and L-OS 57 (50-64, p = .005). By using the receiver operating characteristic curve, an optimal cut off to prevent IaEL related re-interventions was identified by an OS of 30% (p < .001; L-OS 55, p = .006) and to avoid CG stenosis/occlusions by OS 42% (p < .001; L-OS 65, p < .001). In multivariable analysis, aortic endograft OS was the only independent parameter preventive for IaEL related re-intervention (odds ratio, 0.78; 95% confidence interval, 0.61-0.99).

CONCLUSION

With the Endurant-Advanta V12/iCast combination, an aortic stent graft OS of at least 30% (range 30%-42%) should be used to avoid type Ia endoleaks and likewise to ensure CG patency.

Endovascular Aortic Arch Reconstruction with Parallel Grafts: A Dilemma of Excessive Endograft Oversizing

Background

Preservation of supra-aortic branches in thoracic endovascular aortic repair plays a role in associated neurological outcomes, and the strategy varies.

Objectives

This study aimed to evaluate the safety and efficacy of a parallel graft technique to reconstruct the aortic arch.

Methods

From August 2014 to July 2018, a total of 25 patients with thoracic aortic pathologies requiring arch reconstruction were included. All patients underwent thoracic aortic endovascular repair (TEVAR) with a zone 1 landing aortic stent graft, a chimney graft to preserve the left common carotid artery, and a periscope graft to preserve the left subclavian artery. The associated outcomes and complications were reported.

Results

Eighteen patients presented with aortic dissection, 4 with a thoracic aortic aneurysm, 1 with a penetrating aortic ulcer, 1 with a traumatic aortic injury, and 1 case of re-TEVAR. The technical success rate was 96% (24/25), but the case of immediate failure died of retrograde type A dissection. Over a mean follow-up of 32.33 months, another retrograde type A aortic dissection was detected in 1 month, and a case of early failure (< 1 year) and 3 cases of late failure (> 1 year) whose primary aortic problems recurred were detected.

Conclusions

This study demonstrates a total endovascular approach to preserve supra-aortic branches with a parallel graft technique. However, the dilemma of excessive graft oversizing was disclosed due to the risk of retrograde type A dissections and an unsatisfactory durability in this small series.

Various Endoluminal Approaches Available for Treating Pathologies of the Aortic Arch

Open surgical repair of the aortic arch for degenerative aortic disease in an unfit patient is associated with significant morbidity and mortality. Endoluminal techniques have advanced over the last decade. Contemporary endovascular options including a hybrid approach (supra-aortic debranching and aortic stent graft), inner branched endograft, chimney stents, and scallop or fenestrated endografts are being used frequently as an alternative to open surgical arch repair. Understanding of the available endoluminal technology along with careful planning and effective teamwork is required to minimise complications associated with the endoluminal techniques, particularly neurological ones. Custom made techniques are superior to chimney or parallel technology in terms of their complications and durability. Integration of the protective devices such as embolic protection filters into stent design may reduce the risk of poor neurological sequelae. Long-term data are needed to assess the durability of these devices.

Outcomes of elective use of the chimney endovascular technique in pararenal aortic pathologic processes

OBJECTIVE

In the treatment of pararenal abdominal aortic aneurysms and aortic pathologic processes, chimney endovascular aneurysm repair (CHEVAR) represents an alternative technique for urgent cases. The aim of the study was to evaluate the outcomes of CHEVAR in the elective setting.

METHODS

We performed a retrospective analysis of prospectively collected records of 165 consecutive asymptomatic CHEVAR patients who were treated between March 2009 and January 2018 with the Endurant stent graft (Medtronic, Santa Rosa, Calif). A total of 244 chimney grafts (CGs) were implanted. The primary end point was clinical success, defined as freedom from procedure-related mortality, persistent type IA endoleak, occlusion or high-grade stenosis (>70%) of CGs, and any chimney technique-related secondary procedure for the entire follow-up period. Secondary clinical success included patients with successful treatment of a primary end point with a secondary endovascular procedure.

RESULTS

All 244 targeted chimney vessels were successfully cannulated. Total perioperative morbidity was 7.8% (n = 13), including 3 (1.8%) cases of bowel ischemia, 1 (0.6%) patient with renal ischemia, and 1 patient (0.6%) with stroke. Median follow-up was 25.5 ± 2.2 months. Both 30-day and follow-up procedure-related mortality rates were 1.8% (n = 3). Primary and secondary freedom from persistent type IA endoleak rates were 96.4% (n = 159) and 99.4% (n = 164), respectively. Primary and secondary CG patency rates were 92.2% (n = 225) and 95.9% (n = 234), respectively. The rate of reinterventions related to the chimney technique was 10.9% (n = 18), and 83.3% of them were performed by endovascular means. The estimated cumulative primary patency and freedom from persistent type IA endoleak were 87.5% and 95.3%, respectively, and the primary and secondary clinical successes rates at midterm were 80.3% and 87.5%, respectively.

CONCLUSIONS

The elective use of CHEVAR with the Endurant stent graft in our series showed favorable midterm clinical results, which are similar to the published results of other total endovascular modalities. A prospective randomized trial of elective treatment of pararenal abdominal aortic aneurysms and aortic pathologic processes with current endovascular options is needed to assess the value of CHEVAR in the elective setting.

Multicentre Experience with the Chimney Technique for Abdominal Aortic Aneurysms in French University Hospitals

OBJECTIVE

The chimney technique (ChEVAR) allows for proximal landing zone extension for endovascular repair of complex aortic aneurysms. The aim of the present study was to assess ChEVAR national outcomes in French university hospital centres.

METHODS

All centres were contacted and entered data into a computerised online database on a voluntary basis. Clinical and radiological data were collected on all consecutive ChEVAR patients operated on in 14 centres between 2008 and 2016. Patients were deemed unfit for open repair. Factors associated with early (30 day or in hospital) mortality and type 1 endoleak (Type I EL) were calculated using multivariable analysis.

RESULTS

In total, 201 patients with 343 target vessels were treated. There were 94 juxtarenal (46.8%), 67 pararenal (33.3%), 10 Crawford type IV thoraco-abdominal (5%) aneurysms, and 30 (15.1%) proximal failures of prior repairs. The pre-operative diameter was 66.8 ± 16.7 mm and 28 (13.9%) ChEVAR were performed as an emergency, including six (2.9%) ruptures. There were 23 (11.7%) unplanned intra-operative procedures, mainly related to access issues. The rate of early deaths was 11.4% (n = 23). The elective mortality rate was 9.8% (n = 17). Nine patients (4.5%) presented with a stroke. The rate of early proximal Type I EL was 11.9%. Survival was 84.6%, 79.4%, 73.9%, 71.1% at 6, 12, 18, and 24 months, respectively. The primary patency of chimney stents was 97.4%, 96.7%, 95.2%, and 93.3% at 6, 12, 18, and 24 months, respectively. Performing unplanned intra-operative procedures (OR 3.7, 95% CI 1.3-10.9) was identified as the only independent predictor of post-operative death. A ChEVAR for juxtarenal aneurysm was independently associated with fewer post-operative Type I ELs (OR 0.17, 95% CI 0.05-0.58).

CONCLUSION

In this large national ChEVAR series, early results were concerning. The reasons may lie in heterogeneous practices between centres and ChEVAR use outside of current recommendations regarding oversizing rates, endograft types, and sealing zones. Future research should focus on improvements in pre-operative planning and intra-operative technical aspects.

Prevalence and risk factors of acute lower respiratory infection among children living in biomass fuel using households: a community-based cross-sectional study in Northwest Ethiopia

Background

Childhood acute lower respiratory infection in the form of pneumonia is recognized as the single largest cause of childhood death globally accounting for 16% of the overall deaths. Some studies also reported a higher prevalence of childhood acute respiratory infection in Ethiopia, which ranges from 16% up to 33.5%. Concerning the risk factors, there are limited community-based studies in Ethiopia in general, and in the current study region in particular. Therefore, the present study was conducted to investigate the prevalence of childhood acute respiratory infection and associated factors in Northwest Ethiopia.

Methods

As part of the wider stove trial project, a cross-sectional study was conducted in May 2018 among a total of 5830 children aged less than 4 years old in randomly selected clusters. Binary logistic regression was applied to identify factors linked with childhood acute lower respiratory infection and adjusted odds ratios were used as measures of effect with a 95% confidence interval.

Results

A total of 5830 children were included in the study within 100 clusters. Out of which 51.7% were male and 48.3% female. The prevalence of childhood lower acute respiratory infection was 19.2% (95% CI: 18.2–20.2) and found to decrease among children living in homes with chimney, eaves space and improved cookstove than children living in households with no chimney, eaves space and improved cookstove with estimated AOR of 0.60 (95% CI: 0.51–0.70), 0.70 (95% CI: 0.60–0.84) and 0.43 (95% CI: 0.28–0.67) respectively. It was also associated with other cooking-related factors such as cow dung fuel use [AOR = 1.54 (95% CI: 1.02–2.33)], child spending time near stove during cooking [AOR = 1.41 (95% CI: 1.06–1.88), presence of extra indoor burning events [AOR = 2.19 (95% CI: 1.41–3.40)] and with frequent cooking of meals [AOR = 1.55 (95% CI: 1.13–2.13)].

Conclusion

High prevalence of childhood acute lower respiratory infection was demonstrated by this study and it was found to be associated with household ventilation, cooking technology, and behavioral factors. Therefore, we recommend a transition in household ventilation, cooking technologies as well as in child handling and in the peculiar local extra indoor burning practices.

The state of complex endovascular abdominal aortic aneurysm repairs in the Vascular Quality Initiative

BACKGROUND

Endovascular repair of complex abdominal aortic aneurysms has become increasingly common, but reports have mostly been limited to single centers and single devices.

METHODS

We studied all endovascular repairs of complex abdominal aortic aneurysms (zone 6 or caudal) from 2014 to 2018 in the Vascular Quality Initiative. This included all commercially available fenestrated endovascular aneurysm repair (FEVAR), chimney/snorkel repairs, and physician-modified endografts (PMEGs), exclusive of investigational device exemptions and clinical trial devices. We used inverse probability-weighted multilevel logistic regression to compare rates of perioperative outcomes including death, acute kidney injury (AKI), and major adverse cardiac events (MACEs; the composite of death/stroke/myocardial infarction) and Cox regression for long-term mortality.

RESULTS

During the study period, surgeons performed 1396 complex endovascular repairs: 1308 (94%) elective, 63 (4.5%) for symptomatic aneurysms, and 25 (1.8%) for rupture. The number of centers performing complex endovascular repairs expanded steadily from 39 in 2014 to 81 in 2017. There were 880 FEVAR (63%), 256 PMEG (18%), and 260 chimney/snorkel repairs (19%). In elective cases, 3214 visceral vessels were incorporated and revascularized; 120 repairs (9%) involved one vessel, 481 (38%) repairs involved two vessels, 560 (44%) involved three vessels, and 113 (9%) involved four vessels. The mean number of arteries incorporated was 2.5 ± 0.8, with PMEGs involving the most arteries (3.3 ± 0.8 for PMEG vs 2.5 ± 0.6 for FEVAR and 1.9 ± 0.9 for chimney/snorkel; P < .001). PMEGs were used to treat more extensive aneurysms, and more incorporated the celiac and superior mesenteric arteries. There was no change in aneurysm extent, but the length of proximal seal extended over time. Chimney/snorkel cases employed more arm or neck access, had longer procedure times, and used more contrast material. Rates of perioperative death (3.4% for FEVAR vs 2.7% for PMEG vs 6.1% for chimney/snorkel; P = .13) and AKI (17% vs 18% vs 19%; P = .42) were similar, but chimney/snorkel was associated with higher rates of stroke (0.8% vs 0.9% vs 3.3%; P = .03) and MACEs (6.1% vs 5.4% vs 11.7%; P = .02). After adjustment, rates of perioperative death, AKI, and overall complications remained similar, but chimney/snorkel was associated with significantly higher odds of stroke (odds ratio [OR], 7.3 [1.5-36.4]; P = .015), myocardial infarction (OR, 18.7 [2.6-136.8]; P = .004), and MACEs (OR, 11.1 [2.1-58.9]; P = .005). Overall survival after elective repair was 91% at 1 year and 88% at 3 years, with no difference between repair types in crude or adjusted analysis.

CONCLUSIONS

The Vascular Quality Initiative provides a unique opportunity to study the real-world application and outcomes of complex endovascular aneurysm repair. Perioperative morbidity appears to be higher after chimney/snorkel repair, but further study is needed to confirm these findings and to establish the durability of these novel technologies.

Outcomes of Chimney Technique for Preservation of the Left Subclavian Artery in Type B Aortic Dissection

OBJECTIVE

To report outcomes of the chimney technique for preservation of the left subclavian artery (LSA) in patients with type B aortic dissection (TBAD).

METHODS

A retrospective analysis was performed of a prospectively maintained database from August 2012 to October 2017. Primary endpoints were 30 day and overall mortality. Secondary endpoints were technical success, type Ia endoleak, chimney stent occlusion, aortic rupture, stroke, spinal cord ischaemia, and re-intervention rate.

RESULTS

A total of 159 patients (mean age 54 ± 11 years; 141 men) with TBAD were treated using the chimney technique for LSA revascularisation. Acute, subacute, and chronic TBAD accounted for 64%, 28%, and 8% of cases, respectively. One hundred and six cases (67%) were complicated TBAD. One hundred and fifty-six patients (98%) were treated electively, while three (2%) were treated urgently because of intestinal or lower extremity ischaemia. The 30 day mortality and morbidity rates were 2% (3/159) and 4% (7/159), respectively. The technical success rate was 81% (129/159) and immediate type Ia endoleak occurred in 30 (19%) patients. Three major strokes, two spinal cord ischaemia and one aortic rupture, occurred early on. During a mean follow up of 23 ± 16 months (range 1-65 months), three more patients died: from aortic rupture, cerebral haemorrhage, and rectal cancer, respectively. Chimney stent occlusions were observed in four patients and all these chimney stents were self expanding. During follow up, two major strokes, one late type Ia endoleak and one re-intervention, occurred. According to the Kaplan-Meier curve, the estimated one and three year survival rates were 98.1 ± 1.1% and 94.4 ± 2.4%, respectively.

CONCLUSION

Short and mid-term outcomes in the present study demonstrate that the chimney technique is safe and feasible for preservation of the LSA in patients with TBAD, but the durability of chimney stent needs to be evaluated carefully and immediate type Ia endoleak is a concern.

Adjunctive visceral artery chimney in patients undergoing Zenith Fenestrated aortic repair

OBJECTIVE

Visceral artery chimneys have been employed as an adjunct to endovascular aneurysm repair (EVAR) to treat short-neck infrarenal and juxtarenal aortic aneurysms for more than two decades. With the widespread introduction of fenestrated endovascular aneurysm repair by the Food and Drug Administration-approved Zenith Fenestrated endograft (ZFEN; Cook Medical, Bloomington, Ind) to the United States in 2012, clinicians gained the ability to apply the chimney technique to these custom devices for difficult anatomy. The purpose of this report was to demonstrate feasibility and to provide evidence on the performance of chimneys for the treatment of complex juxtarenal aneurysms that could not be adequately treated with ZFEN alone.

METHODS

A retrospective analysis was performed of a prospectively maintained institutional ZFEN database capturing 110 fenestrated endovascular aneurysm repairs from October 2012 to January 2018 to identify patients undergoing a concomitant visceral artery chimney. All patients with <12 months of follow-up were excluded from further analysis. Demographic, anatomic, intraoperative, perioperative, and follow-up characteristics were tabulated and analyzed.

RESULTS

Six patients met criteria and were included in this investigation. They were universally male with a mean age of 76.2 years at the time of ZFEN/chimney. Chimneys were placed in a total of six visceral arteries (n = 1 per patient) consisting of three renal arteries, two celiac arteries, and one accessory renal artery. Mean estimated blood loss and operative time were 283 mL and 298 minutes, respectively. Technical success was achieved in all cases. Two small type IA "gutter" endoleaks were detected early; both spontaneously resolved on follow-up. We observed no instances of chimney migration, stenosis, or thrombosis perioperatively or on follow-up. Two reinterventions were performed in these six patients; these consisted of a repeated renal stent for ostial stenosis at a main body fenestration and a common femoral artery endarterectomy and patch angioplasty for an access-related common femoral artery occlusion.

CONCLUSIONS

Use of ZFEN in conjunction with a singular chimney is safe, feasible, and durable in patients with difficult anatomy who do not meet instructions for use as demonstrated in this limited series.

Characterizing Particulate Matter Exfiltration Estimates for Alternative Cookstoves in a Village-Like Household in Rural Nepal

Alternative stoves are an intervention option to reduce household air pollution. The amount of air pollution exiting homes when alternative stoves are utilized is not known. In this paper, particulate matter exfiltration estimates are presented for four types of alternative stoves within a village-like home, which was built to reflect the use of local materials and common size, in rural Nepal. Four alternative stoves with chimneys were examined, which included an alternative mud brick stove, original Envirofit G3355 model, manufacture altered Envirofit G3355, and locally altered Envirofit G3355. Multiple linear regression was utilized to determine estimates of PM2.5 exfiltration. Overall exfiltration fraction average (converted to a percent) for the four stoves were: alternative mud brick stove with chimney 56%, original Envirofit G3355 model with chimney 87%, manufacture altered Envirofit G3355 model with chimney 69%, and locally altered Envirofit G3355 model with chimney 69%. Alternative cookstoves resulted in higher overall average exfiltration due to direct and indirect ventilation relative to traditional, mud-based stoves. This contrast emphasizes the need for an improved understanding of the climate and health implications that are believed to come from implementing alternative stoves on a large scale and the resultant shift of exposure burden from indoors to outdoors.

A Minor Innovation in Constructing a Small Bowel Stoma in Neonates with Small Bowel Atresia to Reduce the Morbidity

BACKGROUND

Intestinal atresia has still significant morbidity in developing countries. Stomas are now not recommended in every case of intestinal atresia; primary anastomosis is the goal of surgery after resection of dilated adynamic gut. A new type of stoma formation along with primary anastomosis is being presented here.

MATERIALS AND METHODS

This report is based on our experience of many cases with this technique in last 12 years but all the details and long follow-up of each case is not available. However the method of surgical procedure, progress, complications, and advantages encountered have been highlighted.

RESULTS

Presently we have data of 7 patients; others are lost to follow up. Three had died with other associated problems, namely one with multiple atresias, two with septic shock and prematurity. Two stomas did not require formal closure because stoma shriveled and disappeared. Two other stomas had grown very long like a diverticulum when these were closed after 5 and 8 months.

CONCLUSION

This technique is another attempt to decrease morbidity of patients of intestinal atresia especially in those cases where short bowel syndrome is feared after resection of proximal dilated gut.

A Novel Chimney Approach for Management of Horseshoe Kidney During EVAR

INTRODUCTION

Abdominal aortic aneurysms (AAAs) with coexisting horseshoe kidney (HSK) can be difficult to repair, with variable blood supply from the aorta and iliac/mesenteric vessels. Endovascular aneurysm repair (EVAR) has become a popular, less invasive approach to aneurysm care, and a chimney approach to EVAR (ChEVAR) has expanded its use to more complex anatomy. It is mandatory to maintain adequate perfusion to the HSK and visceral branches as part of the treatment of an AAA.

REPORT

A 61-year-old male with an HSK was incidentally found to have an infrarenal AAA that measured 6 cm on a non-contrast computed tomography (CT) scan performed originally for a urologic complaint. A diagnostic angiogram was performed to define arterial anatomy and he was found to have a large inferior mesenteric artery (IMA) arising 1 cm above the level of the aneurysm. ChEVAR was performed to preserve the IMA and flow to the HSK with a completion angiogram revealing patent renal arteries, IMA, and no evidence of an endoleak. Follow-up CT imaging demonstrated a Type II endoleak that resolved upon partial nephrectomy for a right-sided transitional cell carcinoma with resection of the arterial blood supply feeding the Type II endoleak.

DISCUSSION

IMA preservation via ChEVAR is technically feasible and was crucial to preserve blood supply via the IMA to the HSK. Partial nephrectomy treated the transitional cell carcinoma and resolved the Type II endoleak requiring no additional endovascular intervention. A unique treatment course demonstrated the benefits of less invasive interventions when repairing AAA with an HSK.

U-Shape Kissing Chimney Thoracic Endovascular Aneurysm Repair for a Traumatic Arch Rupture in a Polytraumatized Patient

An 18-year-old male patient was admitted to our hospital because of a high impact trauma. A computed tomography scan showed massive mediastinal bleeding due to a posteriorly located rupture of the aortic arch with formation of a pseudoaneurysm. Although urgent repair was indicated, open cardiac surgery was not feasible, as this would involve full heparinization in a patient with subarachnoid bleeding. The chosen solution was to perform a percutaneous thoracic endovascular aneurysm repair (TEVAR) and a kissing chimney procedure using a U-shape configuration.

ChEVAS: Combining Suprarenal EVAS with Chimney Technique

Endovascular sealing with the Nellix(®) endoprosthesis (EVAS) is a new technique to treat infrarenal abdominal aortic aneurysms. We describe the use of endovascular sealing in conjunction with chimney stents for the renal arteries (chEVAS) in two patients, one with a refractory type Ia endoleak and an expanding aneurysm, and one with a large juxtarenal aneurysm unsuitable for fenestrated endovascular repair (EVAR). Both aneurysms were successfully excluded. Our report confirms the utility of chEVAS in challenging cases, where suprarenal seal is necessary. We suggest that, due to lack of knowledge on its durability, chEVAS should only been considered when more conventional treatment modalities (open repair and fenestrated EVAR) are deemed difficult or unfeasible.

The chimney-graft technique for preserving supra-aortic branches: a review

Evolution in the endovascular era has influenced the management of aortic arch pathologies. "Chimney" or "snorkel" graft technique has been used as an alternative in high risk patients unfit for open repair. We reviewed the published literature on the chimney graft technique for preservation of the supra-aortic branches in order to provide an extensive insight of its feasibility and efficacy and investigate its outcomes. 18 reports were identified, with a total of 124 patients and 136 chimney. Primary technical success was achieved in 123/124 patients (99.2%). The perioperative mortality rate was 4.8% and the stroke rate was 4%, while events of spinal cord ischemia were rare. The overall endoleak rate was 18.5%; 13 patients (10.5%) developed a type I endoleak and 10 (8%) patients a type II endoleak. During a median follow-up period of 11.4 months (range, 0.87-20.1 months) all implanted chimney grafts remained patent. From this, we conclude that endovascular aortic arch repair with chimney grafts is associated with a lower mortality rate compared to totally open or hybrid reconstruction. However, the stroke rate remains noteworthy, and requires longterm data to elucidate.