Systematic Review and Meta-analysis of Fenestrated and Chimney/Snorkel Techniques for Endovascular Repair of Juxtarenal Aortic Aneurysms.

OBJECTIVES: Comparative effectiveness of fenestrated endovascular aneurysm repair (FEVAR) and chimney graft endovascular aneurysm repair (ChEVAR) for juxtarenal aortic aneurysms (JAAs) remains unclear. Our objective was to identify and analyze the current body of evidence comparing the effectiveness of both techniques for JAA. METHODS: We performed a systematic review and meta-analysis comparing the effectiveness of FEVAR and ChEVAR for JAA repair. We searched MEDLINE, EMBASE, and Cochrane Register for Controlled Trials from January 1, 1990, for randomized and non-randomized studies assessing outcomes of FEVAR and ChEVAR for JAA repair. Screening, data extraction, risk of bias assessment, and GRADE (Grading of Recommendations, Assessments, Development, and Evaluations) certainty of evidence were performed in duplicate. Data were pooled statistically where possible. RESULTS: Nine retrospective cohort studies comparing the use of FEVAR and ChEVAR for juxtarenal aneurysm were included for meta-analysis. The FEVAR and ChEVAR arms of the meta-analysis consisted of 726 participants and 518 participants, respectively. There were 598 (86.8%) and 332 (81.6%) men in each arm. The mean diameter was larger in the ChEVAR arm (59 mm vs 52.5 mm). Both techniques had similar rates of postoperative 30-day mortality, 3.38% (8/237) versus 3.52% (8/227), acute kidney injury, 16.76% (31/185) versus 17.31% (18/104), and major adverse cardiac events, 7.30% (46/630) versus 6.60% (22/333). The meta-analysis supported the use of FEVAR for most outcomes, with significant advantage for technical success (odds ratio [OR]: 3.24, 95% CI: 1.24-8.42) and avoidance of type 1 endoleak (OR: 5.76, 95% CI: 1.94-17.08), but a disadvantage for spinal cord ischemia (OR: 10.21, 95% CI: 1.21-86.11), which had a very low number of events. The quality of evidence was "moderate" for most outcomes. CONCLUSION: Both endovascular techniques had good safety profiles. The evidence does not support superiority of either FEVAR or ChEVAR for JAA. CLINICAL IMPACT: While lack of equipoise has hampered the design of randomised trials of open versus endovascular repair of juxtarenal aortic aneurysms, concern about the durability of endovascular repair highlights the need for stronger evidence of the comparative efficacy of endovascular techniques. This review performed meta-analysis and evidence appraisal of recent data from large observational studies comparing fenestrated and chimney techniques, using a comprehensive outcome set. Superiority of either intervention could not be established due to differences in participants' baseline risk in each study arm. However, data suggests that both techniques are safe and suitable for use when indicated.

Early and Midterm Outcomes of Chimney Endovascular Aortic Repair for Ruptured Abdominal Aortic Aneurysms.

PURPOSE: To compare the outcomes of endovascular aortic aneurysm repair using a chimney technique (ch-EVAR) with those of the standard EVAR (st-EVAR) for ruptured abdominal aortic aneurysms (RAAA). MATERIALS AND METHODS: We implemented ch-EVAR for juxtarenal RAAA based on obvious anatomical indications after converting the strategy for RAAA from open repair to EVAR. A retrospective, cohort-based study was conducted on patients with RAAA who were treated using EVAR in our hospital between July 2011 and March 2022. EVAR cases were extracted, and outcomes were compared between ch-EVAR and st-EVAR. Patient clinical status, anatomical variables, treatment, and follow-up data were evaluated. RESULTS: A total of 56 (82%) and 12 (18%) patients were treated by st-EVAR and ch-EVAR, respectively. Thirty-day mortality rates were comparable between the 2 groups [8.9% in st-EVAR vs 8.3% in ch-EVAR (p= 0.95)]. Short-term outcomes showed that no type Ia endoleak occurred in either group. Midterm outcomes, including sac enlargement [7.5% in st-EVAR vs 0% in ch-EVAR (p= 0.37)], shrinkage [77.5% in st-EVAR vs 80.0% in ch-EVAR (p= 0.86)], and overall survival and freedom from aneurysm-related reintervention at 3 years [64.7% and 96.4% in the EVAR group vs 91.7% and 100% in the ch-EVAR group, respectively (p= 0.30 and 0.52)], were not significantly different between the 2 groups. CONCLUSION: Ch-EVAR for RAAA showed remarkably excellent outcomes, comparable to those of st-EVAR. Ch-EVAR is considered technically feasible in experienced centers. The indications for EVAR for RAAA may be further expanded using the chimney technique, resulting in overall improved outcomes for RAAA. CLINICAL IMPACT: This is a retrospective, single-center analysis of 68 patients with ruptured abdominal aortic aneurysms (RAAAs) treated by endovascular repair (EVAR) to investigate the efficacy of the chimney technique for juxtarenal RAAA. Thirty-day mortality rate was 8.3% for the chimney EVAR group, which was equivalent to that in the standard EVAR group. Mid-term outcomes including sac enlargement/shrinkage, overall survival, and freedom from aneurysm-related reintervention were comparable between the two groups. This report suggests the possibility of broadening the selection criteria of the current endovascular strategy using the chimney technique.

Comprehensive management of challenging recurrent aortoiliac and lower extremity occlusive disease with simultaneous modified-covered endovascular reconstruction of the aortic bifurcation, inferior mesenteric artery snorkel, and lower extremity bypass.

OBJECTIVES: Despite recent advancements in endovascular technology and proven durability of open surgeries, managing extensive aortoiliac occlusive disease (AIOD) with concurrent severe lower extremity (LE) arterial occlusion remains a formidable challenge. This paper introduces a comprehensive approach to addressing recurrent AIOD and LE occlusive diseases by employing modified-CERAB, inferior mesenteric artery (IMA) snorkel, and LE bypass in a challenging case. METHODS: A 56-year-old male patient presented with subacute bilateral lower extremity rest pain with dry gangrene in the left great toe and a complex medical history. His history included a hostile abdomen stemming from past ischemic bowel episodes and multiple bowel resections through laparotomies. Furthermore, the patient had a persistent left ventricular thrombus (LVT), stage-2 chronic kidney disease (CKD), diabetes, and was currently experiencing bilateral LE rest pain and dry gangrene in the left great toe, accompanied by severe dermatitis in both LEs. RESULTS: He successfully underwent modified-CERAB with a concurrent snorkel technique for IMA preservation, along with an LE bypass to resolve bilateral LE critical ischemia. CONCLUSION: This comprehensive management approach, combining simultaneous modified-CERAB, IMA snorkel, and LE bypass, provides an effective alternative for addressing complex AIOD and LE occlusive disease patients with hostile abdomen.

A microscopic scenario on recovery mechanisms under waterlogging and submergence stress in rice.

MAIN CONCLUSION: Adaptive traits in rice responding to flooding, a compound stress, are associated with morpho-anatomical and physiological changes which are regulated at the genetic level. Therefore, understanding submergence stress tolerance in rice will help development of adapted cultivars that can help mitigate agricultural losses. Rice is an important dietary component of daily human consumption and is cultivated as a staple crop worldwide. Flooding is a compound stress which imposes significant financial losses to farmers. Flood-affected rainfed rice ecosystems led to the development of various adaptive traits in different cultivars for their optimal growth and survival. Some cultivars can tolerate hypoxia by temporarily arresting elongation and conserving their energy sources, which they utilize to regrow after the stress conditions subside. However, few other cultivars rapidly elongate to escape hypoxia using carbohydrate resources. These contrasting characters are regulated at the genetic level through different quantitative trait loci that contain ERF transcription factors (TFs), Submergence and Snorkels. TFs can simultaneously activate the transcription of various genes involved in stress and development responses. These TFs are of prime importance because the introgressed and near-isogenic lines showed promising results with increased submergence tolerance without affecting yield or quality. However, the entire landscape of submergence tolerance is not entirely depicted, and further exploration in the field is necessary to understand the mechanism in rice completely. Therefore, this review will highlight the significant adaptive traits observed in flooded rice varieties and how they are regulated mechanistically.

Salvage of an Incomplete Sandwich With a Covered Celiac Trunk and a "Floating" Superior Mesenteric Artery Stent in a Thoracoabdominal Aortic Aneurysm.

PURPOSE: To report a case of a patient with a large thoracoabdominal aortic aneurysm (TAAA) extent V treated with a custom-made fenestrated and branched endovascular repair (F/B-EVAR) after a failed and incomplete attempt of a Sandwich repair technique. REPORT: An 83-year-old patient was referred to our department after a failed attempt at endovascular repair of type V TAAA with a sandwich technique. The celiac trunk was inadvertently covered with the first endograft and a covered long superior mesenteric artery stent was placed and left facing upward inside the aorta. We performed a staged repair, by first catheterizing and stenting the celiac trunk and bringing it under and inside the main aortic endograft. In interval, a F/B-EVAR was performed using a bimodular custom-made device (CMD) with a proximal 2 branch module for the celiac trunk and superior mesenteric artery and distal module with fenestrations for both renal arteries. The intervention was successful, and the follow-up was uneventful at 6 months. CONCLUSIONS: Re-intervention after failed endovascular attempts of TAAA repair are technically challenging and require advanced endovascular techniques. The ability to construct CMDs allowed to extend repair to our patient which had severe anatomical constraints for other techniques.

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.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: Forty-nine multiple ChEVAR were performed in 44 men and 5 women, with complete outcome data at a mean follow-up of 18 months. 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 60.5 mm; p = 0.059), iliac diameter (7.3 vs 7.1 mm; 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 25.0 mm; p = 0.021), shorter native infrarenal neck (0.5 vs 3.37 mm; p = 0.002) as well as longer seal zone (36.33 vs 22.67 mm; 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 15.7 mm3; p = 0.73) nor the rate of persistent gutter-flow (12.5 vs 9.1%; p = 0.71). CONCLUSION: 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.

The Effect of Breathing Laterality on Hip Roll Kinematics in Submaximal Front Crawl Swimming.

The purpose of this study was to determine the effect of breathing laterality on hip roll kinematics in submaximal front crawl swimming. Eighteen elite competitive swimmers performed three 100 m front crawl trials at a consistent sub-maximal speed (70% of seasonal best time) in a 25 m pool. Each trial was performed with one of three different breathing conditions: (1) unilateral breathing (preferred side), (2) bilateral breathing (alternating left/right-side every 3 strokes) and (3) simulated non-breathing using a swim snorkel. A waist-mounted triaxial accelerometer was used to determine continuous hip roll angle throughout the trial, from which peak hip roll angles (Ó¨) and average angular velocities (ω) were calculated. Two-way repeated measures ANOVAs were used to identify significant main effects for laterality (preferred vs. non-preferred breathing sides) and condition (unilateral, bilateral and snorkel breathing) for both Ó¨ and ω. Peak hip roll to the preferred side was significantly greater (p < 0.001) in the unilateral condition, while ω to the non-preferred side was significantly greater in the unilateral (p < 0.01) and bilateral (p < 0.04) conditions. Significant same-side differences were also found between the different breathing conditions. The results demonstrate that breathing laterality affects hip roll kinematics at submaximal speeds, and that unilateral and snorkel breathing are associated with the least and most symmetric hip roll kinematics, respectively. The findings show that a snorkel effectively balances and controls bilateral hip rotation at submaximal speeds that are consistent with training, which may help to minimize and/or correct roll asymmetries that are the result of unilateral breathing.

Covered endovascular reconstruction of the aortic bifurcation associated to a snorkel technique for inferior mesenteric artery preservation.

Aortic distal occlusion has been usually treated by open surgery. A persisting patent and overdeveloped inferior mesenteric artery (IMA) suggests a significant participation in the bowel circulation. Coverage of the inferior mesenteric artery (IMA) origin could compromise the bowel circulation. Covered endovascular reconstruction of the aortic bifurcation (CERAB) is a proven and guideline-suggested alternative for revascularization of the distal aortic occlusion. CERAB associated to a snorkel to the IMA aims to reduce the risk of bowel ischemia keeping and percutaneous and minimal invasive approach.

Outcomes of chimney/snorkel endovascular repair for symptomatic and ruptured abdominal aortic aneurysms.

OBJECTIVE: Symptomatic and ruptured abdominal aortic aneurysms (AAAs) are increasingly being managed with endovascular aneurysm repair (EVAR). We aimed to identify the outcomes of symptomatic and ruptured AAAs that had undergone EVAR with a chimney or snorkel technique (ChEVAR). METHODS: A retrospective cohort study was performed using the Vascular Quality Initiative registry from March 2013 to July 2019. All patients with symptomatic and ruptured AAAs with a proximal aortic zone of disease from 6 to 9 who had undergone ChEVAR were included. The outcomes were analyzed in accordance with the Society for Vascular Surgery reporting standards for EVAR. RESULTS: ChEVAR was performed in 77 patients (ruptured, 35 [45.5%]; symptomatic, 42 [54.5%]). The median age was 73.0 years (interquartile range [IQR], 67.0-81.0 years), and 54 patients (70.1%) were men. The median maximum aneurysm diameter was 67.5 mm (IQR, 54.5-83.3 mm). All patients had American Society of Anesthesiologists class ≥III. For the patients with ruptured AAAs, the mean lowest preoperative systolic blood pressure was 95.3 ± 29.3 mm Hg. The fluoroscopy time was 57.4 minutes (IQR, 41.2-79.0 minutes). The proximal aortic zone of disease was zone 6 in 9 (11.7%), zone 7 in 21 (27.3%), zone 8 in 36 (46.8%), and zone 9 in 11 (14.3%) patients. ChEVAR involved more than one vessel in 55 patients (71.4%). No significant difference was found in 30-day mortality between the patients with ruptured vs symptomatic AAAs (11.4% vs 7.1%; P = .695). Reintervention was required for 10 patients (13.0%) at a median of 9 postoperative days, 2 (20.0%) of whom died. Postoperatively, 31 patients (40.3%) had experienced a major complication. A type I endoleak had occurred in nine patients (11.7%), two (22.2%) of whom died. Long-term follow-up data were available for 38 patients (49.4%) at a median of 406.5 days (IQR, 326.8-602.0 days) postoperatively. Of the 18 patients with long-term radiographic data, sac growth was detected in 4 (22.2%). A total of 14 patients had died at a median of 26.5 days (IQR, 3.0-468.5 days). CONCLUSIONS: ChEVAR for symptomatic and ruptured AAAs can be performed with acceptable rates of morbidity and mortality. Long-term data are needed to determine the durability.

Evaluation of N95 respirators, modified snorkel masks and low-cost powered air-purifying respirators: a prospective observational cohort study in healthcare workers.

Disposable N95 respirator masks are the current standard for healthcare worker respiratory protection in the COVID-19 pandemic. In addition to shortages, qualitative fit testing can have low sensitivity for detecting poor fit, leading to inconsistent protection. Multiple groups have developed alternative solutions such as modified snorkel masks to overcome these limitations, but validation of these solutions has been lacking. We sought to determine if N95s and snorkel masks with attached high-efficiency filters provide consistent protection levels in healthcare workers and if the addition of positive pressure via an inexpensive powered-air purifying respirator to the snorkel mask would provide enhanced protection. Fifty-one healthcare workers who were qualitatively fitted with N95 masks underwent quantitative mask fit testing according to a simulated workplace exercise protocol. N95, snorkel masks with high-efficiency filters and snorkel masks with powered-air purifying respirators were tested. Respiratory filtration ratios were collected for each step and averaged to obtain an overall workplace protocol fit factor. Failure was defined as either an individual filtration ratio or an overall fit factor below 100. N95s and snorkel masks with high-efficiency filters failed one or more testing steps in 59% and 20% of participants, respectively, and 24% and 12% failed overall fit factors, respectively. The snorkel masks with powered-air purifying respirators had zero individual or overall failures. N95 and snorkel masks with high-efficiency filter respirators were found to provide inconsistent respiratory protection in healthcare workers.

Extracting chemical reactions from text using Snorkel.

BACKGROUND: Enzymatic and chemical reactions are key for understanding biological processes in cells. Curated databases of chemical reactions exist but these databases struggle to keep up with the exponential growth of the biomedical literature. Conventional text mining pipelines provide tools to automatically extract entities and relationships from the scientific literature, and partially replace expert curation, but such machine learning frameworks often require a large amount of labeled training data and thus lack scalability for both larger document corpora and new relationship types. RESULTS: We developed an application of Snorkel, a weakly supervised learning framework, for extracting chemical reaction relationships from biomedical literature abstracts. For this work, we defined a chemical reaction relationship as the transformation of chemical A to chemical B. We built and evaluated our system on small annotated sets of chemical reaction relationships from two corpora: curated bacteria-related abstracts from the MetaCyc database (MetaCyc_Corpus) and a more general set of abstracts annotated with MeSH (Medical Subject Headings) term Bacteria (Bacteria_Corpus; a superset of MetaCyc_Corpus). For the MetaCyc_Corpus, we obtained 84% precision and 41% recall (55% F1 score). Extending to the more general Bacteria_Corpus decreased precision to 62% with only a four-point drop in recall to 37% (46% F1 score). Overall, the Bacteria_Corpus contained two orders of magnitude more candidate chemical reaction relationships (nine million candidates vs 68,0000 candidates) and had a larger class imbalance (2.5% positives vs 5% positives) as compared to the MetaCyc_Corpus. In total, we extracted 6871 chemical reaction relationships from nine million candidates in the Bacteria_Corpus. CONCLUSIONS: With this work, we built a database of chemical reaction relationships from almost 900,000 scientific abstracts without a large training set of labeled annotations. Further, we showed the generalizability of our initial application built on MetaCyc documents enriched with chemical reactions to a general set of articles related to bacteria.

Retrospective evaluation of the endovascular repair of the anastomotic pseudoaneurysm of the transplanted renal artery using the snorkel technique.

OBJECTIVE: To evaluate the endovascular repair of the transplanted renal artery anastomotic pseudoaneurysm using the snorkel technique. METHODS: From April 2012 to December 2017, we performed endovascular repair in six patients, who were diagnosed with transplanted renal artery anastomotic pseudoaneurysm, using the snorkel technique. The "snorkel" stent and the "parallel" stent were placed in the transplanted kidney and the external iliac artery, respectively. Another covered stent was implanted at the proximal end of the external iliac artery to match the diameter of the iliac artery.Result and conclusion: Of the six patients, three patients recovered. Two patients experienced pseudoaneurysm rupture due to infection, and one patient developed stent thrombosis; all three patients underwent graft nephrectomy. The endovascular treatment of transplanted renal artery anastomotic pseudoaneurysm with the snorkel technique is a feasible method but needs to comply with certain indications.

Complex endovascular aneurysm repair is associated with higher perioperative mortality but not late mortality compared with infrarenal endovascular aneurysm repair among octogenarians.

OBJECTIVE: As our collective experience with complex endovascular aneurysm repair (EVAR) has grown, an increasing number of older patients are being offered endovascular repair of juxtarenal aneurysms. Outcomes after complex EVAR in this older subpopulation are not well-described. We sought to specifically evaluate clinical outcomes after complex EVAR compared with infrarenal EVAR in a cohort of octogenarians. METHODS: A single-center retrospective review was conducted using a database of consecutive patients treated with elective EVAR for abdominal aortic aneurysms (AAAs) between 2009 and 2015. Only patients 80 years of age or older were included. Patients in the complex EVAR group were treated with either snorkel/chimney or fenestrated techniques, whereas infrarenal EVAR consisted of aneurysm repair without renal or visceral involvement. Relevant demographic, anatomic, and device variables, and clinical outcomes were collected. RESULTS: There were 103 patients (68 infrarenal, 35 complex) treated within the study period with a mean follow-up of 21 months. A total of 75 branch grafts were placed (59 renal, 11 celiac, 5 superior mesenteric artery) in the complex group, with a target vessel patency of 98.2% at latest follow-up. Patients undergoing complex EVAR were more likely to be male (82.8% vs 60.2%; P = .02) and have a higher prevalence of renal insufficiency (71.4% vs 44.2%; P = .008). The 30-day mortality was significantly greater in patients treated with complex EVAR (8.6% vs 0%; P = .03). There were no differences in major adverse events (P = .795) or late reintervention (P = .232) between groups. Interestingly, sac growth of more than 10 mm was noted to be more frequent with infrarenal EVAR (17.6% vs 2.8%; P = .039). However, both type IA (5.7% infrarenal; 4.9% complex) and type II endoleaks (32.3% infrarenal; 25.7% complex) were found to be equally common in both groups. Complex EVAR was not associated with increased all-cause mortality at latest follow-up (P = .322). Multivariable Cox modeling demonstrated that AAAs greater than 75 mm in diameter (hazard ratio; 4.9; 95% confidence interval, 4.6-48.2) and renal insufficiency (hazard ratio, 3.71; 95% confidence interval, 1.17-11.6) were the only independent risk factors of late death. CONCLUSIONS: Complex EVAR is associated with greater perioperative mortality compared with infrarenal EVAR among octogenarians. However, late outcomes, including the need for reintervention and all-cause mortality, are not significantly different. Larger aneurysms and chronic kidney disease portends greater risk of late death after EVAR, regardless of AAA complexity. These patient-related factors should be considered when offering endovascular treatment to older patients.

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.

Cardiac Pulsatility- and Respiratory-Induced Deformations of the Renal Arteries and Snorkel Stents After Snorkel Endovascular Aneurysm Sealing.

Purpose: To quantify deformations of renal arteries and snorkel stents after snorkel endovascular aneurysm sealing (Sn-EVAS) resulting from cardiac pulsatility and respiration and compare these deformations to patients with untreated abdominal aortic aneurysms (AAA) and snorkel endovascular aneurysm repair (Sn-EVAR). Materials and Methods: Ten Sn-EVAS patients (mean age 75±6 years; 8 men) were scanned with cardiac-gated, respiration-resolved computed tomography angiography. From 3-dimensional geometric models, changes in renal artery and stent angulation and curvature due to cardiac pulsatility and respiration were quantified. Respiration-induced motions were compared with those of 16 previously reported untreated AAA patients and 11 Sn-EVAR patients. Results: Renal artery bending at the stent end was greater for respiratory vs cardiac influences (6°±7° vs -1°±2°, p<0.025). Respiration caused a 3-fold greater deformation on the left renal artery as compared with the right side. Maximum curvature change was higher for respiratory vs cardiac influences (0.49±0.29 vs 0.24±0.17 cm-1, p<0.025), and snorkel renal stents experienced similar maximum curvature change due to cardiac pulsatility and respiration (0.14±0.10 vs 0.19±0.09 cm-1, p=0.142). When comparing the 3 patient cohorts for respiratory-induced deformation, there was significant renal branch angulation in untreated AAAs, but not in Sn-EVAR or Sn-EVAS, and there was significant bending at the stent end in Sn-EVAR and Sn-EVAS. Maximum curvature change due to respiration was ~10-fold greater in Sn-EVAR and Sn-EVAS compared to untreated AAAs. Conclusion: The findings suggest that cardiac and respiratory influences may challenge the mechanical durability of snorkel stents of Sn-EVAS; similarly, however, respiration may be the primary culprit for tissue irritation, increasing the risk for stent-end thrombosis, especially in the left renal artery. The bending stiffness of snorkel stents in both the Sn-EVAR and Sn-EVAS cohorts damped renal branch angulation while it intensified bending of the artery distal to the snorkel stent. Understanding these device-to-artery interactions is critical as they may affect mechanical durability of branch stents and quality and durability of treatment.

Chimney parallel grafts and thoracic endovascular aortic repair for blunt traumatic thoracic aortic injuries: A systematic review.

BACKGROUND: Whilst the management of blunt traumatic thoracic aortic injury has seen a paradigm shift to an 'endovascular first' approach, the limitations of thoracic endovascular aortic repair remain. An inadequate proximal landing zone limits the use of thoracic aortic stent grafts and in an emergent polytrauma setting, aortic arch debranching via open surgery may not be practical or feasible. A wholly endovascular approach to debranching utilising 'off-the-shelf' stents and parallel graft techniques may represent a possible solution. Hence, we sought to perform a systematic review investigating the use of chimney graft techniques alongside thoracic aortic stenting in blunt traumatic thoracic aortic injury. METHODS: We performed the systematic review in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Searches were performed on Medline (PubMed), Web of Science and Scopus to identify articles describing the use of chimney grafts in traumatic aortic transection (PROSPERO: CRD42017082549). RESULTS: The systematic search revealed 172 papers, of which 88 duplicates were removed resulting in 84 papers to screen. Based on title, abstract and full text review, six articles were included for final analysis. There were nine patients in total with an average age of 41 (three females, five males, one unspecified), all with significant polytrauma, secondary to the mechanism of injury. A variety of stents were used between centres, with techniques showing a predominance to stenting of the left subclavian artery (77%, n = 7). The technical success rate was 82%, with two (18%) cases of type 1 endoleaks, of which one resolved spontaneously. CONCLUSIONS: Despite the encouraging results, this by no means provides for a firm conclusion given the small sample size. Patients should still be judiciously selected on a case-by-case basis when employing the chimney graft technique. Larger cohort studies are needed to establish these findings.

The Prophylactic Chimney Snorkel Technique for the Prevention of Acute Coronary Occlusion in High Risk for Coronary Obstruction Transcatheter Aortic Valve Replacement/Implantation Cases.

Coronary occlusion (immediate or delayed) is an uncommon but potentially devastating complication of transcatheter aortic valve replacement/implantation (TAVR/TAVI). Several patient-related, anatomical, device and procedural risk factors can be assessed to risk-stratify patients and assist in procedural planning. In patients at high risk for coronary occlusion, coronary protection measures should be employed. In the highest risk patients, consideration should be given to prophylactic techniques to prevent coronary occlusion. This how-to-do-it report provides a framework for risk assessment for coronary occlusion followed by a step-wise description of the emerging chimney snorkel coronary stenting technique as a predictable procedural approach for the management of this potentially challenging clinical scenario.

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.

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.