Graft Configuration Research Articles

A Revolutionary Device for Endovascular Aortic Repair of Abdominal Aortic Aneurysm: A Pilot Study

Background Endovascular repair for abdominal aortic aneurysms (AAA) has been the gold standard since it was established in 1991. Various graft configurations have been developed to overcome the limitations of endovascular aortic repair (EVAR), including contralateral gate cannulation (CGC). We propose a new device and technique intended to simplify endovascular AAA repair, along with reports of its application in six patients. Intervention The Taofan and Kang (T&K) bidirectional endovascular aortic repair (B-EVAR (B-EVAR) device uses a main-body stent graft, two-limb extensions, and bare metal stent. The procedure involved accessing the right and left femoral arteries, followed by standard aortography evaluation using a pigtail catheter through the contralateral femoral access. The main body stent graft is deployed through ipsilateral femoral access using a balloon catheter, while the contralateral gate is cannulated with a hydrophilic coated wire. Both balloons were inflated simultaneously to ensure that the wires were in different lumens. Contralateral and ipsilateral extensions were deployed using a limb extension stent graft. Standard aortography evaluation was repeated. Result T&K B-EVAR pilot procedures proved successful in various cases, from simple to complex anatomy, and even with varied graft stent deployment strategies. None of the patients had complications or prolonged length of stay (LOS). Follow-up CT did not reveal any high-pressure endoleaks. Conclusion T&K B-EVAR has been proven to simplify endovascular AAA repair in six patients with excellent results. It is also reproducible, potentially universally applicable, and can offer operators ease of use, faster procedure times, reduced fluoroscopy times, and reduced contrast usage.

Total arterial revascularization with RIMA-LIMA-Y configuration in patients with left subclavian artery stenosis.

Subclavian artery stenosis (SAS) occurs in 6% of patients undergoing coronary artery bypass grafting (CABG). Complications such as subclavian-coronary steal are common. Revascularization options in such cases remain debatable. In this case series, all patients with angina, had severe triple vessel disease on angiography. All tests including computed tomography (CT) angiography of neck vessels, were done as part of routine workup for CABG. The patients, all males, had a mean age of 66.5 years with three of them having hypertension and diabetes. All were ex-smokers with mean ejection fraction (EF) of 60.1%. CT angiography of neck vessels revealed that two patients had moderate to severe while one had severe left SAS and another had severe proximal left internal mammary artery (LIMA) stenosis. Total arterial revascularization was performed, with an average of 3.5 distal grafts. The LIMA graft was employed in a Y graft configuration, anastomosed to in-situ right internal mammary artery (RIMA). All patients had uneventful postoperative stay and were discharged with a mean hospital stay of 3.8 days. There were no postoperative strokes, myocardial infarction, neurological symptoms, or change in EF. At 6-month follow-up, they were asymptomatic and doing well. The RIMA-LIMA-Y configuration can be a safe, viable option in CABG for patients with left SAS. It is challenging, with re-entry and judicious utilization of the length of LIMA being of paramount importance. The importance of CT angiography of neck vessels to detect SAS cannot be under-emphasized.

How to Use a Right Internal Thoracic Artery Graft in On- and Off-Pump Coronary Artery Bypass Grafting

In coronary artery bypass grafting, internal thoracic artery grafts and other arterial grafts have shown superior results compared with saphenous vein grafts. The right internal thoracic artery (RITA) has been reported as one of these various arterial graft options. However, there are some limitations and concerns associated with using the RITA. This review presents the current topics and scientific evidence on the use of RITA grafts in coronary artery bypass grafting. The reviewed papers mainly focus on the operative results of using the RITA, graft configurations and target vessels, and the comparison between on- or off-pump coronary artery bypass procedure. The results of these studies suggest the followings. The method of using the RITA (either in situ or as a free graft) should be selected based on the need to reach crucial targets and the number of required target vessels. A free RITA graft anastomosed to the aorta with modified proximal anastomosis allows for the revascularization of multiple vessels with acceptable flow characteristics. For revascularization of the right coronary artery system with low-grade proximal stenosis, the RITA should not be used. The decision to use cardiopulmonary bypass depends on the patient's condition, target vessels, as well as the experience of institution. Skeletonized harvesting is more effective in preventing sternal wound infections in coronary artery bypass grafting using bilateral internal thoracic arteries compared with using a single internal thoracic artery.

Pulmonary Artery Endograft Implantation Using a Parallel Stent Grafting Technique to Enable the Treatment of a Bronchial Anastomosis Complication After Lung Transplantation.

Bronchial stenosis associated with bronchial anastomosis dehiscence after lung transplantation is a catastrophic complication following lung transplantation with a paucity of therapeutic solutions. To describe an adaptation of the parallel stent grafting technique in the pulmonary arterial territory to treat this challenging situation. This is a case report of a 52-year-old patient who presented bronchus stenosis and bronchial anastomosis dehiscence after lung transplantion. Bronchial stenting and lung retransplantation were contraindicated. Therefore, an endovascular approach using pulmonary artery endograft placement to prevent bleeding during repeated right bronchial balloon dilation was propposed. The technique consists of the deployment of an aortic extender endoprosthesis in the right main pulmonary artery and a balloon expandable stent in the upper lobe pulmonary artery (using a parallel graft configuration) through the common femoral and right internal jugular veins, respectively. Intraoperative transesophageal echocardiogram and one-lung ventilatory ventilation are needed. The patient underwent a new bronchoscopy 16 days after the procedure, that showed epithelization at the previous eroded zone, enabling bronchocopic balloon dialtion to be safely performed. A post-operative contrast-enhanced CT scan revealed an adequate positioning of the stent grafts. Despite all eforts, the patient succumbed to ventilator associated pneumonia on postoperative day 108. The technique's advantages include its feasibility even in situations in which other techniques may be contraindicated and its potential use in emergencies. Its limitations include the need for experienced interventionists to perform it, and the potential risk of acute tricuspid regurgitation. This study illustrates the early feasibility of the parallel stent grafting technique applied to the pulmonary artery territory. However, it's safety profile regarding infectious risk was not demontrated.

Clinical and Angiographic Outcomes of Bilateral Internal Thoracic Artery Revascularization: In Situ vs Free Grafts

BackgroundBilateral internal thoracic artery (ITA) grafting is associated with improved long-term outcomes; however, the appropriate graft configuration remains controversial. We compared the long-term outcomes of different graft configurations. MethodsBetween 2009 and 2015, 1171 patients underwent isolated bilateral ITA grafting for left-sided complete revascularization at 4 Japanese cardiac surgery centers: underwent in situ left ITA to the left anterior descending artery plus in situ right ITA to the left circumflex artery (LR group, n = 278), in situ right ITA to the left anterior descending artery plus in situ left ITA to the left circumflex artery (RL group, n = 665), and in situ left ITA to the left anterior descending artery plus free right ITA to the left circumflex artery (free group, n = 228). Major adverse cardiovascular events (MACEs), including mortality, myocardial infarction and revascularization, and ITA patency, were compared. ResultsAmong the 3 groups, the free group showed significantly lower MACEs and overall mortality rates (P < .001). Nonfatal myocardial infarction and revascularization rates showed no marked differences among the groups. A weighted analysis revealed a decreased risk of MACEs and death in the free group. No marked difference was observed in the patency of the ITA anastomosed to the left anterior descending artery. Patency of the ITA grafted to the circumflex artery in the LR group was significantly lower relative to the other groups. Using a free right ITA grafted to the circumflex artery reduced the risk of graft failure. ConclusionsThe free right ITA configuration for left-sided revascularization might have better long-term outcomes and significantly better patency than other grafts.

Influence of Diabetes Mellitus on Changes in Intra-Operative Decision Making in Coronary Artery Bypass Grafting

Background: We evaluated whether patients with diabetes mellitus experienced more surgical strategy changes than patients without diabetes when undergoing coronary artery bypass graft surgery utilizing a protocol for intraoperative high frequency ultrasound and transit-time flow measurement. Methods: Outcomes of coronary artery bypass grafting (CABG) patients with and without diabetes enrolled in the multicenter prospective Registry for Quality Assessment with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery (REQUEST) study were retrospectively compared. The primary endpoint was frequency of intraoperative surgical strategy changes. We also evaluated the differences in patient characteristics and operative characteristics including graft configuration. Results: We compared 614 non-diabetic patients with 402 diabetic patients, among whom 128 were insulin dependent. Patients with diabetes had higher rates of surgical strategy change for the aortic component of the operation (10.2% vs. 6.4%, odds ratio (OR) = 1.67; 95% confidence interval (CI) = 1.06–2.65; p = 0.026). Surgical strategy changes related to in-situ conduits were more common in on-pump procedures in comparison to off-pump in diabetics (4.0% vs. 0%; p = 0.007). Diabetes was associated with less frequent use of bilateral internal mammary arteries (BIMA) (25.6% vs. 33.7%; p = 0.006), more frequent use of radial artery (31.3% vs. 16.9%; p &lt; 0.001) and multi-arterial configuration (48.3% vs. 39.9%, p = 0.009), and more total grafts (3.1 ± 1.1 vs. 2.8 ± 0.9; p &lt; 0.001). Conclusions: When performing isolated CABG on diabetic patients, surgeons were more likely to change surgical strategy for the aortic component of the operation based on high-frequency ultrasound (HFUS), and more likely to make a change related to in-situ conduits in on-pump procedures in diabetics. Among diabetic patients, there was less frequent use of BIMA, more frequent use of radial artery, more frequent multi-arterial configuration, and more total grafts.

A Revolutionary Device for Endovascular Aortic Repair of Abdominal Aortic Aneurysm: A Pilot Study

Background Endovascular repair for abdominal aortic aneurysms (AAA) has been the gold standard since it was established in 1991. Various graft configurations have been developed to overcome the limitations of endovascular aortic repair (EVAR), including contralateral gate cannulation (CGC). We propose a new device and technique intended to simplify endovascular AAA repair, along with reports of its application in six patients. Intervention The Taofan and Kang (T&amp;K) bidirectional endovascular aortic repair (B-EVAR (B-EVAR) device uses a main-body stent graft, two-limb extensions, and bare metal stent. The procedure involved accessing the right and left femoral arteries, followed by standard aortography evaluation using a pigtail catheter through the contralateral femoral access. The main body stent graft is deployed through ipsilateral femoral access using a balloon catheter, while the contralateral gate is cannulated with a hydrophilic coated wire. Both balloons were inflated simultaneously to ensure that the wires were in different lumens. Contralateral and ipsilateral extensions were deployed using a limb extension stent graft. Standard aortography evaluation was repeated. Result T&amp;K B-EVAR pilot procedures proved successful in various cases, from simple to complex anatomy, and even with varied graft stent deployment strategies. None of the patients had complications or prolonged length of stay (LOS). Follow-up CT did not reveal any high-pressure endoleaks. Conclusion T&amp;K B-EVAR has been proven to simplify endovascular AAA repair in six patients with excellent results. It is also reproducible, potentially universally applicable, and can offer operators ease of use, faster procedure times, reduced fluoroscopy times, and reduced contrast usage.

The Gore Viabahn balloon-expandable stent graft as a bridging stent in complex endovascular aortic procedures at 3 years performs better in fenestrations

ObjectiveComplex endovascular procedures are now recognized as the gold standard treatments for extensive aortic diseases. Bridging stents (covered stents used to couple the aortic graft to the visceral vessels) play a pivotal role, yet there is currently no dedicated device available on the market. The aim of the study was to evaluate the midterm performance of the Gore Viabahn balloon-expandable (VBX) stent graft as a bridging stent for target visceral vessels (TVVs). MethodsData from all consecutive patients who underwent a fenestrated and branched endovascular aortic repair and received the VBX stent graft as a bridging stent between July 2018 and September 2022 were prospectively collected and subsequently analyzed retrospectively. Primary end points included freedom from TVV instability and freedom from TVV-related reinterventions, both overall and in comparison between branched and fenestrated graft configurations. Secondary end points were overall survival, procedure and TVV-related (in an intent-to-treat basis) technical success, freedom from type IC/IIIC endoleak, and freedom from TVV patency loss. ResultsSixty-three patients were treated with a fenestrated and branched endovascular aortic repair using the VBX stent graft as a bridging stent, of whom 47 (74.6%) presented an atherosclerotic aneurysm, 7 (11.1%) a post-dissecative aneurysm, and 9 (14.3%) an anastomotic pseudoaneursym or a type IA endoleak in a previous endovascular aortic repair. Included in the aortic repair were 231 of 243 (95.1%) total visceral vessels. The intraoperative requirement of 13 additional VBX stent grafts determined a TVV-related technical success of 94.4%. The mean follow-up was 26.1 ± 16.4 months. The estimated overall survival at 36 months was 73% ± 7.5%. The estimated rates at 36 months for freedom from type IC/IIIC endoleaks and TVV primary patency were 90.6% ± 3.9% and 99% ± 0.7%, respectively. The estimated rate at 36 months for freedom from TVV instability was 92.1% ± 3% and did not differ between branched and fenestrated configurations, whereas freedom from TVV-related reinterventions was 90.6% ± 3.1% and significantly in favor of fenestrations (69.4% vs 96.8%, P < .001). Multivariate analyses confirmed fenestrated configuration as a protective factor against TVV-related reinterventions (hazard ratio: 0.079; 95% confidence interval: 0.016-0.403). ConclusionsThe VBX stent graft proves to be a reliable bridging stent for complex aortic procedures involving both fenestrated and branched endografts. Although immediate results are deemed satisfactory, they favor fenestrations regarding the need of reinterventions through 3 years. The success of the procedure heavily relies on a thorough understanding of the unique characteristics of this stent.

Single bundle hamstrings autograft preparation techniques for anterior cruciate ligament reconstruction: current concepts.

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures, and huge variation exists in the surgical technique. Single bundle hamstrings autograft reconstruction is a common method and has good clinical outcomes. A criticism of the hamstrings autograft is a small graft diameter, often less than 8-mm, which has been associated with increased re-rupture rates. Several graft preparation techniques for single bundle hamstrings autograft exist. Perioperative decisions include the number of tendons utilized, number of graft strands, graft configuration, and femoral and tibial fixation methods. Awareness of the minimum tendon and graft length required to produce each graft variation is necessary to avoid common pitfalls. However, intraoperative graft modification is possible to maximize graft diameter, and obtain proper fixation. The objective of this current concepts review is to describe the indications, surgical anatomy, technique, intraoperative tips, clinical outcomes, and complications for single bundle hamstrings autograft preparation techniques in ACLR.

Lessons Learned with Enhanced Recovery for Open Abdominal Aortic Aneurysm Surgery: A Long Term Regional Network Experience

This enhanced recovery programme (ERP) aimed to achieve early recovery for patients undergoing major surgery. Results of a standardised ERP protocol for open infrarenal abdominal aortic aneurysm (AAA) repair within a hub and spoke regional network are presented. In this monocentric prospective study (January 2004 - December 2021), consecutive AAAs (≥ 55 mm) were included in the ERP (patient discharge on post-operative day [POD] 4). The four phases of the ERP were pre-admission, pre-operative, intra-operative, and post-operative. Exclusion criteria were BMI > 35 kg/m2, functional capacity < 4 MET, previous aortic or abdominal surgery, and life expectancy < 5 years. Transperitoneal surgery was undertaken with routine AAA resection, graft interposition, and closure. Consecutive patients (n = 778) were enrolled into the study (mean age 72.3 ± 3.2 years; n = 712 men); 160 (20.5%) were treated in spoke hospitals. Median follow up was 78 (IQR 28, 128) months; median length of stay, procedure time, and blood loss were 4 days (IQR 3, 5), 190 min (IQR 170, 225), and 564 mL (IQR 300, 600). Infrarenal clamping and tube graft configuration were used in 96.5% (n = 751) and 72.5% (n = 564) of patients; 30 day mortality and complication rates were 0.4% (n = 3) and 9.2% (n = 72). Discharge after POD 4 occurred in 15.0%, and most significant predictors for discharge after POD 4 were haemotransfusion, re-intervention, and ileus over 3 days. Overall survival was: 98.2% at 1 year, 85.0% at 5 years, and 59.9% at 10 years. Freedom from re-intervention was 97.9% at 1 year, 94.1% at 5 years, and 86.8% at 10 years. Short and long term outcomes were comparable between hub and spoke hospitals. The ERP protocol was associated with low short and long term mortality and complication rates. Future studies should apply the ERP protocol to other vascular centres.

Sex Comparative Analysis of Branched and Fenestrated Endovascular Aortic Arch Repair Outcomes

Female sex is a risk factor for adverse events after endovascular aortic repair. Sex comparative early and midterm outcomes of fenestrated and branched endovascular aortic arch repair (F/B-Arch) are presented. A single centre retrospective sex comparative analysis of consecutive patients managed with F/B-Arch was conducted according to STROBE. Primary outcomes were sex comparative technical success, death, and cerebrovascular morbidity at 30 days. Kaplan-Meier estimates were used for follow up outcomes. Among 209 patients, 38.3% were women. Coronary artery disease (p < .001) and previous myocardial infarction (p= .01) were more common in women. Non-native proximal aortic landing was higher in women (women: 51.3%; men: 31.8%, p= .005) and the aortic dissection rate was lower (28.8% vs. 48.1%, p= .005). Proximal landing to Ishimaru zones showed no difference (zone 0: p= .18; zone 1: p= .47; zone 2: p= .39). Graft configurations were equally distributed. In total, 416 supra-aortic trunks were bridged. The median number of revascularisations per patient was two (interquartile range 1, 3), with no difference between sexes (p= .54). Technical success (women: 97.5%; men: 96.9%, p= .80), 30 day mortality rate (women: 10%; men: 9.3%, p= .86), and cerebrovascular morbidity (women: 11.3%; men: 17.1%, p= .25) were similar. Women presented more access related complications (women: 32.5%; men: 16.3%, p= .006), without affecting access related re-interventions (p= .55). Survival (women: 81.1%, 95% confidence interval [CI] 76.3 - 85.9%; men: 79.8%, 95% CI 76.0 - 83.6%) and freedom from re-intervention (women: 56.6%, 95% CI 50.4 - 62.8%; men: 55.3%, 95% CI 50.1 - 60.5%) at 12 months were similar (log rank, p= .40 and p= .41, respectively). Both sexes presented similar outcomes after F/B-Arch. Appropriate patient selection may decrease the effect of sex in F/B-Arch outcomes.

Selecting conduits for coronary artery bypass grafting: caution regarding the right internal mammary artery

This narrative review summarizes the angiographic and clinical outcome results of the most common coronary artery bypass grafting (CABG) conduits. The left internal mammary artery is the preferred first conduit to bypass the left anterior descending artery due to superior long-term survival and graft patency. Recent studies suggest the radial artery may be the preferred second conduit for the circumflex or right coronary artery territories, challenging the belief that the right internal mammary artery is the best choice. Despite their historical high failure rates, saphenous vein grafts continue to be widely used as secondary conduits. Several recent studies report suboptimal rates of right internal mammary artery graft failure, with clinical outcomes comparable to or worse than saphenous veins. The suboptimal rates of RIMA graft failure may be attributed to several factors such as improvements in vein graft failure rates, the use of in situ and non-left anterior descending artery grafting configurations, and skeletonized harvesting techniques. While observational studies favor multiple over single arterial grafting, randomized studies are needed for confirmation. The ongoing Randomized comparison of the clinical Outcome of single vs. Multiple Arterial grafts (ROMA) trial aims to determine if multiple arterial grafting reduces major adverse cardiovascular events and mortality and how secondary conduit selection influences these outcomes. Greater adoption of arterial grafting strategies is likely to come from high-quality evidence of benefit and safety from ongoing and future large pragmatic trials.

National trends in utilization of surgeon-modified grafts for complex and thoracoabdominal aortic aneurysms

IntroductionCustom-branched/fenestrated grafts are widely available in other countries, but in the United States, they are limited to a handful of centers, with the exception of a 3-vessel juxtarenal device (ZFEN). Consequently, many surgeons have turned to alternative strategies such as physician-modified endografts (PMEGs). We therefore sought to determine how widespread the use of these grafts is. MethodsWe studied all complex endovascular repairs of complex and thoracoabdominal aortic aneurysms in the Vascular Quality Initiative from 2014 to 2022 to examine temporal trends. ResultsA total of 5826 repairs were performed during the study period: 1895 ZFEN, 3241 PMEG, 595 parallel grafting, and 95 where parallel grafting was used in addition to ZFEN, with a mean of 2.7 ± 0.98 vessels incorporated. Over time, the number of PMEGs steadily increased, both overall and for juxtarenal aneurysms, whereas the number of ZFENs essentially leveled off by 2017 and has remained steady ever since. In the most recent complete year (2021), PMEGs outnumbered ZFENs by over 2:1 overall (567 to 256) and nearly twofold for juxtarenal repairs. In three-vessel cases involving juxtarenal aneurysms, PMEGs were used as frequently as ZFENs (43% vs 43%), whereas the proportion of juxtarenal aneurysms repaired using a four-vessel graft configuration increased from 20% in 2014 to 29% in 2021 (P < .001). The differences in PMEG use were more pronounced as surgeon volume increased. Surgeons in the lowest quartile of volume performed <2 complex repairs annually, evenly split between PMEGs and ZFENs. However, surgeons in the highest quartile of volume performed a median of 18 (interquartile range: 10-21) PMEGs/y, but only 1.6 (interquartile range: 0.8-3.4) ZFENs/y. The number of physician-sponsored investigational device exemption trials of PMEGs has expanded from 1 in 2012 to 8 currently enrolling. As those data are not included in the Vascular Quality Initiative, the true number of PMEGs is likely substantially higher. ConclusionsPMEGs have become the dominant endovascular repair modality of complex abdominal and thoracoabdominal aortic aneurysms outside of investigational device exemptions. The field of endovascular aortic surgery and patients with complex aneurysms would benefit from broader publication of PMEG techniques, outcomes, and comparisons to custom-manufactured grafts.

A hemodynamic study of blood flow models on various stent graft configurations during aorto-iliac reconstruction.

To compare the hemodynamic performance of three (Bottom Up non-ballet, Top-Down non-ballet, Top Down ballet) idealized stent graft configurations used during endovascular repair of abdominal aortic aneurysms, under the influence of various rheological models. Ten rheological models are assumed and a commercial finite volume solver is employed for the simulation of blood flow under realistic boundary conditions. An appropriate mesh convergence study is performed and five hemodynamic variables are computed: the time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), endothelial cell activation potential and displacement force (DF) for all three configurations. The choice of blood flow model may affect results, but does not constitute a significant determinant on the overall performance of the assumed stent grafts. On the contrary, stent graft geometry has a major effect. Specifically, the Bottom Up non-ballet type is characterized by the least favorable performance presenting the lowest TAWSS and the highest OSI, RRT and ECAP values. On the other hand, the Top Down ballet type presents hemodynamic advantages yielding the highest TAWSS and lowest OSI, RRT and ECAP average values. Furthermore, the ballet type is characterized by the lowest DF, although differences observed are small and their clinical relevance uncertain. The effect of the assumed rheological model on the overall performance of the grafts is not significant. It is thus relatively safe to claim that it is the type of stent graft that determines its overall performance rather than the adopted blood flow model.

Total Arterial Revascularization: Evaluating the Length of the Radial Artery in a Composite Graft Configuration.

Reimplanting the radial artery in the left internal thoracic artery as a composite graft allows total arterial revascularization (TAR) without aortic manipulation. The limitation of this strategy is the length of the radial artery required to reach distal right coronary artery (RCA) branches. Our analysis focuses on the feasibility of this strategy. A total of 169 patients underwent TAR using the radial artery in a composite grafting configuration. Length of the radial artery, number of sequential anastomoses, heart size, target location, length of the arm, patient height, body surface area, and flow in the composite graft were prospectively collected. The mean length of the radial artery was 18.02 cm. Patients with a mean length of the radial artery of 15.9 cm needed an extension of the radial artery with another conduit to reach the RCA distal branches. When T-configuration is used, the length of the radial artery should be 0.53 cm per sequential anastomosis to reach the RCA distal branches. Our study shows that an average length of 18.02 cm of radial artery is needed to reach targets on the RCA distal branches in composite grafting. In T-configuration, we need 0.53 cm more length per anastomosis to achieve TAR.

Techniques and Technologies to Improve Vein Graft Patency in Coronary Surgery.

Vein grafts are the most used conduits in coronary artery bypass grafting (CABG), even though many studies have suggested their lower patency compared to arterial alternatives. We have reviewed the techniques and technologies that have been investigated over the years with the aim of improving the quality of these conduits. We found that preoperative and postoperative optimal medical therapy and no-touch harvesting techniques have the strongest evidence for optimizing vein graft patency. On the other hand, the use of venous external support, endoscopic harvesting, vein preservation solution and anastomosis, and graft configuration need further investigation. We have also analyzed strategies to treat vein graft failure: when feasible, re-doing the CABG and native vessel primary coronary intervention (PCI) are the best options, followed by percutaneous procedures targeting the failed grafts.

Comparison of bare and nonbare stent grafts during thoracic endovascular aneurysm repair of the aortic arch

ObjectiveWe compared the outcomes of patients treated with nonbare stents (NBS) and proximal bare stents (PBS) endografts with a proximal landing zone in the aortic arch during thoracic endovascular aortic repair (TEVAR). MethodsWe conducted a retrospective cohort, observational, multicenter study that included 361 consecutive TEVAR procedures undertaken between November 2005 and December 2021. TEVAR patients with both BS and NBS Relay stent graft configurations with proximal landing in zones 1, 2, or 3 were enrolled. Preoperative anamnestic and morphological data, clinical outcomes, and aortic modifications 30 days after surgery and at the latest follow-up available were collected. The primary outcome was freedom from proximal endoleak (type IA) comparing the two configurations. Total and detailed endoleak rates, clinical and technical success, intraoperative additional maneuvers, major adverse events, and reinterventions were secondary outcomes. ResultsThe median follow-up was 4.9 (interquartile range, 2.0-8.1) years. No statistically significant difference between NBS and PBS patients concerning 30-day major adverse events, retrograde aortic dissection, disabling stroke, or late type IA endoleak (10.8% vs 7.8%; P = .597). Aneurysmal disease (P = .026), PLZ diameter of >34 mm (P = .026), aortic tortuosity index of >1.4 (P = .008), type III aortic arch (P = .068), and PLZ thrombus (P = .014) identified as risk factors by univariate Cox regression analysis. PLZ thrombus was the only type IA endoleak risk factor at multivariate Cox regression (P = .016). ConclusionsWe found no statistically significant difference in freedom from type IA endoleak, retrograde dissection, or disabling stroke observed between the NBS and the BS configuration of the Relay endograft. Proximal landing zone thrombotic apposition was a prominent risk factor for type IA endoleak after TEVAR.

A new class of “structure-by-design” polymer membranes for organic solvent nanofiltration with controllable selectivity

Membrane based separations offer an inexpensive and energy efficient pathway to purification. However, their use is often stifled during separation of organics due to low selectivity. This can be attributed to the inherent limitations of the synthesis methods employed, namely, interfacial polymerization and phase inversion. In this work, a new class of structure-by-design membranes are synthesized by surface modification of crosslinked polyimide using graft polymerization with a series of methacrylate monomers with differing chain lengths and chemistries. Graft polymerization of long chain monomers resulted in increased selectivity (α∼3.7 for 80-20 mol.% MeOH-toluene and α∼6 for 95-5 mol.% toluene-triisopropyl benzene (TIPB) for both test solutions) as a result of increased stiffness and order (using GIWAXS)). The observed selectivities renders these membranes competitive for organic solvent nanofiltration applications. In addition, pure solvent permeabilities were measured. The performance of these membranes was correlated with brush properties such as degree of grafting (using ATR-FTIR), surface polarity (contact angle measurements), stiffness (using QCM-D) and brush configuration in different solvent environments (using MD Simulations). MD simulations demonstrate that in mixtures containing hydrophobic species, polymers with longer hydrophobic side chains well more and form fuller matrices leading to increased solvent accessible surface area. GIWAXS results showed increased order with longer side chain length. These tunable membranes offer promise for organics separation.

Anatomical Compliance of Cavopulmonary Assist Device Designs: A Virtual Fitting Study in Fontan Patients.

Several device designs for cavopulmonary mechanical circulatory support (MCS) are under investigation, however, challenged by the Fontan population's heterogeneity in size, cardiovascular and thoracic anatomy. This study aimed to preclinically assess the anatomical compliance of proposed device designs in silico. Representative double- and single-outlet cavopulmonary assist device (CPAD) designs were virtually implanted into CT imaging data of 10 patients previously palliated with total cavopulmonary connection (TCPC) for functionally univentricular hearts. Anatomical device compatibility was characterized concerning pump proximity to cardiovascular, respiratory and thoracic structures, as well as pump in- and outflow graft configuration. In 10 Fontan patients with a median age of 10.4 years (interquartile range [IQR] 5.0-15.3 years) and a median body surface area of 1.09 m2 (IQR 0.76-1.28 m2), implantation of a double-outlet CPAD was feasible in 1 patient (10%). In all other, adverse device intersection with the trachea and (neo-)aorta, or posterior pulmonary artery outflow graft kinking were observed. A single-outlet design permitted enhanced device mobilization adapting to individual anatomical conditions, resulting in device fit in nine of 10 patients (90%). Despite vast anatomical variations among single ventricle patients, a single-outlet device design may provide intracorporeal cavopulmonary MCS to a broad spectrum of failing Fontan patients.

High-speed videography of an exemplary porcine aortic valve after the valve-sparing aortic root replacement using the straight graft configuration.

High-speed videography of an exemplary porcine aortic valve after the valve-sparing aortic root replacement using the straight graft configuration.