Retraction: Computational fluid dynamics in the numerical simulation analysis of end-to-side anastomosis for coarctation of the aorta.
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ABSTRACT:
SUBMITTER: Yang F
PROVIDER: S-EPMC8024844 | biostudies-literature | 2021 Mar
REPOSITORIES: biostudies-literature
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Retraction: Computational fluid dynamics in the numerical simulation analysis of end-to-side anastomosis for coarctation of the aorta.
Yang Fang F Zhai Bo B Hou Li-Gong LG Zhang Qian Q Wang Jie J
Journal of thoracic disease 20210301 3
[This retracts the article DOI: 10.21037/jtd.2018.11.37.]. ...[more]
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Project description:ObjectivesEnd-to-side anastomosis is common in coronary artery bypass grafting, although restrictive suturing can narrow the anastomosis. We evaluated ex vivo end-to-side models by numerically simulating fluid dynamics to compare various degrees of stenotic anastomoses to predict haemodynamic effects.MethodsA carotid artery was grafted via an end-to-side anastomosis onto the left anterior descending artery of a porcine heart, with liquid silicone injected into the vessels. The end-to-side image was acquired via multidetector computed tomography for reference, and models of longitudinal shortening and bilateral narrowing were created with 25%, 50%, 75%, along with 90%, and 100% stenosis in the native coronary artery. Haemodynamics were analysed using computational fluid dynamics simulations to calculate streamlines, wall shear stress and oscillatory shear index.ResultsIn the reference model, the graft inflow impinged on the floor of the native artery, creating a recirculating vortex and a high oscillatory shear index region near the heel. As the graft flow angle increased with longitudinal stenosis, bilateral stenosis generated helical flow near the lateral wall of the native artery, worsening with increased stenosis. At 75% stenosis, both longitudinal shortening and bilateral narrowing caused abnormal flow separation, with low wall shear stress and high oscillatory regions forming distal to the toe of the anastomosis.ConclusionsComputational fluid dynamics modelling predicts that end-to-side anastomoses with 75% longitudinal or bilateral stenosis are at a risk of intimal hyperplasia causing graft failure, while anastomotic stenosis <50% indicates acceptable haemodynamics. Future studies should explore long-term clinical outcomes with suboptimal surgical anastomotic construction.Clinical registration numberNot applicable.
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Project description:BackgroundAortic coarctation (CoA) is a congenital heart disease that usually combines various cardiovascular malformations, including hypoplastic aortic arch (HAA). We explore end-to-side anastomosis (ESA) and autologous pulmonary artery patch (APAP) in CoA with HAA, to provide more clinical experience.MethodsThis is a single-center retrospective study. The target population is patients with aortic stenosis and HAA who underwent surgery between 2015 and 2021. All cases included were consecutive, and no instances were omitted due to absent data, lack of consent, or other factors. Collect information on gender, age, and weight at the time of the operation, detailed information on the constricted segment and pressure gradient evaluated by echocardiography and computed tomography (CT), and other factors of patients, and these data were analyzed by statistical methods.ResultsNinety-six patients (67 males and 29 females) with median age of 76 (41.75, 128.50) days and median weight of 4.20 (3.70, 5.10) kg were enrolled. The follow-up period was 46.20 (34.40, 54.70) months. The patients were divided into two groups based on surgery: ESA (G1, 59) and APAP (G2, 37). The combined cardiovascular malformations were treated simultaneously. None of the patients had neurological events or renal failure, and three died early after the operation. Finally, 93 patients were successfully followed-up. Cox regression showed that ESA was a risk factor for aortic arch geometry is closer to Gothic (G-AAg), elevated blood pressure (EBp), and aortic recoarctation (reCoA) after surgery. In G1, 18 patients had G-AAg (P=0.03), 13 had EBp (P=0.041), and 12 had reCoA (P=0.041), all of which were significantly higher than those in G2 (three had G-AAg, one of whom had EBp and reCoA).ConclusionsIt is safe and effective to repair CoA and HAA and other cardiovascular malformations through one-stage median sternotomy. Compared with ESA, APAP can lower the risks of G-AAg, EBp, and reCoA. Although APAP takes longer, the proper application of selective antegrade cerebral perfusion may lower the risks. We recommend expanding the indications for APAP when circumstances allow, which will benefit patients.
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Project description:Atherosclerotic plaque in the descending thoracic aorta (dAo) is related to altered wall shear stress (WSS) for normal patients. Resection with end-to-end anastomosis (RWEA) is the gold standard for coarctation of the aorta (CoA) repair, but may lead to altered WSS indices that contribute to morbidity.Computational fluid dynamics (CFD) models were created from imaging and blood pressure data for control subjects and age- and gender-matched CoA patients treated by RWEA (four males, two females, 15 ± 8 years). CFD analysis incorporated downstream vascular resistance and compliance to generate blood flow velocity, time-averaged WSS (TAWSS), and oscillatory shear index (OSI) results. These indices were quantified longitudinally and circumferentially in the dAo, and several visualization methods were used to highlight regions of potential hemodynamic susceptibility.The total dAo area exposed to subnormal TAWSS and OSI was similar between groups, but several statistically significant local differences were revealed. Control subjects experienced left-handed rotating patterns of TAWSS and OSI down the dAo. TAWSS was elevated in CoA patients near the site of residual narrowings and OSI was elevated distally, particularly along the left dAo wall. Differences in WSS indices between groups were negligible more than 5?dAo diameters distal to the aortic arch.Localized differences in WSS indices within the dAo of CoA patients treated by RWEA suggest that plaque may form in unique locations influenced by the surgical repair. These regions can be visualized in familiar and intuitive ways allowing clinicians to track their contribution to morbidity in longitudinal studies.
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Project description:BackgroundLymphaticovenous anastomosis is an important surgical treatment for lymphedema, with lymphaticovenous side-to-end anastomosis (LVSEA) and lymphaticovenous end-to-end anastomosis being the most frequently performed procedures. However, LVSEA can cause lymphatic flow obstruction because of regurgitation and tension in the anastomosis. In this study, we introduce a novel and simple procedure to overcome this problem.MethodsThirty-five female patients with lower extremity lymphedema who underwent lymphaticovenous anastomosis at our hospital were included in this study. Eighty-five LVSEA procedures were performed, of which 12 resulted in insufficient venous blood flow. For these 12 anastomoses, the proximal lymphatic vessel underwent clipping after the anastomotic procedure and the venous inflow was monitored. Subsequently, the proximal ligation after side-to-end anastomosis recovery (PLASTER) technique, which involves ligating the proximal side of the lymphatic vessel, was applied. A postoperative evaluation was performed using indocyanine green 6 months after surgery.ResultsDespite the clipping procedure, three of the 12 anastomoses still showed poor venous inflow. Therefore, it was not possible to apply the PLASTER technique in those cases. Among the nine remaining anastomoses in which the PLASTER technique was applied, three (33%) were patent.ConclusionsOur findings show that achieving patent anastomosis is challenging when postoperative venous inflow is poor. We achieved good results by performing proximal ligation after LVSEA. Thus, the PLASTER technique is a particularly useful recovery technique when LVSEA does not result in good run-off.
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Project description:ObjectiveThe number of bypasses is the most important factor in lymphaticovenular anastomosis (LVA) for lymphedema treatment. Side-to-end (S-E) LVA, which can bypass bidirectional lymph flows via one anastomosis, is considered to be the most efficient bypass, but creation of lateral window to a small lymphatic vessel is technically demanding. To overcome the difficulty, we introduced S-E anastomosis through temporary lymphatic expansion (SEATTLE) procedure in S-E LVA.MethodsThis was a retrospective observational study set in a teaching hospital. Forty eight lower extremity lymphedema (LEL) patients underwent LVA. S-E LVAs were performed with (SEATTLE group) or without (non-SEATTLE group) temporary lymphatic expansion. S-E LVAs were evaluated to compare anastomosis result in SEATTLE and non-SEATTLE groups.ResultsS-E LVAs resulted in 44 anastomoses in SEATTLE group (n = 25) and 37 anastomoses in non-SEATTLE group (n = 23). LEL index reduction in SEATTLE group was significantly greater than that in non-SEATTLE group (16.5±14.5 vs. 10.9±11.8, P = 0.041). Success rate of S-E LVA in SEATTLE group was significantly higher than that in non-SEATTLE group (95.5% vs 81.1%, P = 0.040). Thirty seven of 44 (84.1%) lymph vessels in SEATTLE group were successfully dilated by temporary lymphatic expansion maneuver. All of 9 failed S-E LVAs used a lymphatic vessel with diameter of 0.35 mm or smaller.ConclusionsThe SEATTLE procedure facilitates S-E LVA by a simple and easy maneuver. When the diameter of the lymphatic vessel is 0.35 mm or smaller even after the temporary lymphatic expansion maneuver, S-E LVA is not recommended due to relatively high failure rate.
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Project description:BackgroundAccording to previously published studies, esophagectomy with modified Collard anastomosis has been reported to have low incidences of anastomotic leak and stricture. However, the optional anastomotic method after esophagectomy is still controversial. We conducted this study to compare the incidence of postoperative anastomotic stricture formation and dysphagia over three years after an esophagectomy with modified Collard anastomosis (MC) or end-to-side (ETS) hand-sewn anastomosis. Meanwhile, the early postoperative anastomotic leakage and other complications, hospital stay and 30- and 90-day mortality were also evaluated.MethodsThe clinical data of 905 patients undergoing McKeown esophagectomy were retrospectively reviewed. The rate of postoperative stricture formation after three years was demonstrated by stricture-free survival which is the primary end-point of this study. The incidence of dysphagia, first time of onset of stricture and number of dilatations were also recorded during follow-up.ResultsThe incidence of anastomotic leak tended to be higher in the MC group compared with that in the ETS group (13.0% vs. 8.7%, P = 0.064). The rates of anastomotic stricture in the MC group were significantly less than in the ETS group (P = 0.004). The number of dilatations in the MC group were significantly greater than those in the ETS group (2.34 vs. 2.46, P = 0.011).ConclusionsA modified Collard cervical esophagogastric anastomosis was associated with lower rates of anastomotic stricture and dysphagia, compared with ETS hand-sewn anastomosis. However, the modified Collard anastomosis is accompanied by an increased anastomotic leakage rate.
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Project description:Microsurgery simulation courses increasingly use assessment methodologies to evaluate the quality of microvascular anastomosis and to provide constructive feedback in competency-based training. Assessment tools evaluating the "journey" of skill acquisition in anastomosis have evolved, including global rating scores, hand motion analysis, and evaluation of the final outcome, that is, "end-product" assessment. Anastomotic patency is the gold standard end-product in clinical microvascular surgery, and in vivo end-to-side anastomosis, which can be confirmed using the Acland-test. Microsurgery simulation training is moving to include nonliving models, where possible, according to the principles of the replacement, reduction, and refinement of the use of animals in research. While a standardized end-product assessment tool for nonliving end-to-end anastomosis exists, there is no similar tool for end-to-side anastomosis. Intimal surface suture line assessment is an error list-based tool, which involves exposing the intimal surface of a vessel and analysis of the quality of suture placement. Errors in end-to side anastomosis were classified according to the potential clinical significance (high, medium, or low) perceived by the senior authors. Intimal surface suture line assessment provides constructive feedback during microsurgery training, helping to minimize technical errors, which are likely to impact on the final outcome in a clinical environment. Intimal surface suture line assessment lends itself to nonliving simulation training courses as an end-product self-assessment tool, especially during the early learning curve, to demonstrate progression. It has intraoperative relevance by assessment of the intimal surface suture line as the final sutures are placed in an end-to-side anastomosis to provide objective feedback to trainees in relation to likely physiological anastomotic outcome.
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Project description:Membrane distillation (MD) is widely used in the field of seawater desalination. Among its various sub-categories, air gap membrane distillation (AGMD) stands out due to its high thermal efficiency and compatibility with low-grade heat sources. This study delves into the impact of varying operating conditions on AGMD performance, employing numerical simulations which are grounded in experimental validation. The objective was to enhance the performance of AGMD, mitigate polarization phenomena, and provide a reference for optimizing membrane component design. The results show that the agreements between the simulated and the experimental values were high. When increasing the feed temperature and decreasing the coolant temperature, the impact of polarization phenomena on the performance of AGMD was reduced. The mass flux, Total Permeate Concentration (TPC), and heat flux increased by 81.69%, 36.89%, and 118.01%, respectively, when the feed temperature was increased from 50 °C to 75 °C. When the coolant temperature decreased from 22 °C to 7 °C, the mass flux increased by 37.06%. The response surface analysis revealed that the feed temperature has significant influence on AGMD performance, and there is a noticeable interaction between the feed temperature and coolant temperature. These findings will play key roles in practical applications.
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Project description:BackgroundThe development of current anesthetic and surgical techniques has increased the success rate of complex tracheal resection and reconstruction. End-to-end anastomosis is the prevailing method, while the end-to-side approach has also been reported to be practical and suitable. The current study aimed to demonstrate the feasibility and advantages of the end-to-side anastomosis method in specific cases.MethodsWe summarized 6 cases of patients with tracheobronchial tumors who received different end-to-side airway reconstructions in our center. Their clinical features and surgical procedures were also described. Postoperative follow-up was conducted to monitor their complications and prognosis.ResultsAmong the patients involved in the study, 2 patients with tumors involving the bronchus intermedius received auto-lung transplantations under general anesthesia, 3 patients with tumors involving the lower trachea and carina underwent reconstruction under non-intubated combined anesthesia, and 1 patient with left main bronchus (LMB) involvement received surgery under venoarterial extracorporeal membrane oxygenation (VA ECMO)-supported non-intubated anesthesia. The surgical procedures were completed successfully without surgical or anesthetic incidents. Patients 1 and 2 underwent auto-lung transplantation with distal stumps and trachea end-to-side anastomosis (right lower lobe and right basal segment). Patients 3 and 4 received right main bronchus (RMB) to lateral trachea reconstruction, while Patients 5 and 6 underwent LMB to tracheal wall anastomosis. Anastomotic buttressing was performed using the thymus and mediastinal tissue. The patients were discharged within 2 weeks of the operation. No severe postoperative complications were reported, with the exception of Patient 5, who required a prolonged intensive care unit (ICU) stay with antibiotics due to pneumonia. Anastomotic necrosis, dehiscence, or stenosis were not observed in the postoperative bronchoscopy.ConclusionsEnd-to-side anastomosis is a feasible and effective surgical method in airway reconstructions. This method facilitates tension-free anastomosis, which is crucial for surgical prognosis and decreasing complications. The reported cases had ideal surgical results during follow-up. The long-term outcomes of the end-to-side method require further evaluation.
| S-EPMC8902089 | biostudies-literature
Project description:Background Abnormal aortic elastic properties are major notable vasculopathy involved in coarctation of the aorta (CoA). However, there are no reports on aortic wall elastic characteristics in fetuses with CoA. Methods and Results Fifty-six fetuses with CoA and 56 normal controls were included in this prospective case-control study. The dimensions of the cardiac chamber, the size of the aorta, left ventricular myocardial performance indexes, and aortic elastic properties, including the global circumferential strain, fractional area change and mean longitudinal strain, were measured serially in utero. The global circumferential strain, fractional area change, and mean longitudinal strain in fetuses with CoA were smaller than those in the normal group at both the first and last examinations (18.50% versus 37.73% for global circumferential strain, 38.90% versus 57.55% for fractional area change, 6.61% versus 11.81% for mean longitudinal strain at first scan, 16.62% versus 42.05% for global circumferential strain, 36.54% versus 59.7% for fractional area change, 6.2% versus 11.46% for mean longitudinal strain at last scan, all P<0.001). There were negative correlations between aortic elastic properties and left ventricular myocardial performance indexes in fetuses with CoA (P<0.01). Aortic elastic properties were correlated positively with aortic isthmus size in fetuses with CoA (P<0.01). Conclusions Aortic strain and the fractional area change were decreased in fetuses with CoA. Impairments of these aortic elastic properties were associated with diminished heart function and aortic isthmus size in utero. Further large-scale longitudinal studies are required to confirm the potential predictive value of cardiovascular morbidity (ie, hypertension) in fetuses with CoA.
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