Project description:Treatment of aortic arch aneurysms and dissections require highly complex surgical procedures with devastating complications and mortality rates. Currently, repair of the complete arch until the proximal descending thoracic aorta consists of a two-stage procedure, called elephant trunk (ET) technique, or a single stage a single-stage technique referred to as frozen elephant trunk (FET). There is conflicting evidence about the perioperative results of ET in comparison with FET. We carried out a meta-analysis to investigate possible differences in perioperative and early (up to 30 days) outcomes of ET vs. FET, particularly for mortality, spinal cord injury (SCI), stroke, and renal failure. We also performed a meta-regression to explore the effects of age and sex as possible cofactors. Twenty-one studies containing data from interventions conducted between 1997 and 2019 and published between 2008 and 2021 with 3153 patients (68.5% male) were included. ET was applied to 1,693 patients (53.7%) and FET to 1460 (46.3%). Overall mortality after ET was 250/1693 (14.8%) and after FET 116/1460 (7.9%). Relative risk (RR) and 95% confidence interval (CI) were 1.37 [1.04 to 1.81], p = 0.027. There was no significant effect of age and sex. SCI occurrence after the second stage of ET was 45/1693 (2.7%) and after FET 70/1,460 patients (4.8%) RR 0.53 [0.35 to 0.81], p = 0.004. Age and sex were not associated with the risk of SCI. No significant differences were observed between ET and FET in the incidence of stroke and renal failure. Our results indicate that ET is associated with higher early mortality but lower incidence of SCI compared to FET. When studies published in the last 5 years were analyzed, no significant differences in mortality or SCI were found between ET and FET. This difference is attributed to a decrease in mortality after ET, as the mortality after FET did not change significantly over time.
Project description:BackgroundAim of this study was to report and to identify risk factors for distal aortic failure following aortic arch replacement via the frozen elephant trunk (FET) procedure.MethodsOne hundred eighty-six consecutive patients underwent the FET procedure for acute and chronic aortic dissection. Our cohort was divided into patients with and without distal aortic failure. Distal aortic failure was defined as: (I) distal aortic reintervention, (II) aortic diameter dilatation to ≥ 6 cm or > 5 mm growth within 6 months, (III) development of a distal stent-graft-induced new entry (dSINE) and/or (IV) aortic-related death. Preoperative, intraoperative, postoperative and aortic morphological data were analyzed.ResultsDistal aortic failure occurred in 88 (47.3%) patients. Forty-six (24.7%) required a distal reintervention, aortic diameter dilatation was observed in 9 (4.8%) patients, a dSINE occurred in 22 (11.8%) patients and 11 (6.4%) suffered an aortic-related death. We found no difference in the number of communications between true and false lumen (p = 0.25) but there were significantly more communications between Ishimaru zone 6-8 in the distal aortic failure group (p = 0.01). The volume of the thoracic descending aorta measured preoperatively and postoperatively within 36 months afterward was significantly larger in patients suffering distal aortic failure (p < 0.001; p = 0.011). Acute aortic dissection (SHR 2.111; p = 0.007), preoperative maximum descending aortic diameter (SHR 1.029; p = 0.018) and preoperative maximum aortic diameter at the level of the diaphragm (SHR 1.041; p = 0.012) were identified as risk factors for distal aortic failure.ConclusionThe incidence and risk of distal aortic failure following the FET procedure is high. Especially those patients with more acute and more extensive aortic dissections or larger preoperative descending aortic diameters carry a substantially higher risk of developing distal aortic failure. The prospective of the FET technique as a single-step treatment for aortic dissection seems low and follow-up in dedicated aortic centers is therefore paramount.
Project description:ObjectivesOur aim was to investigate the occurrence and clinical consequence of postoperative in-stent thrombus formation following the frozen elephant trunk (FET) procedure.MethodsPostoperative computed tomography angiography (CTA) scans of all 304 patients following the FET procedure between 04/2014 and 11/2021 were analysed retrospectively. Thrombus size and location were assessed in multiplanar reconstruction using IMPAX EE (Agfa HealthCare N.V., Morstel, Belgium) software. Patients' characteristics and clinical outcomes were evaluated between patients with and without thrombus formation.ResultsDuring the study period, we detected a new postoperative in-stent thrombus in 19 patients (6%). These patients were significantly older (p = 0.009), predominantly female (p = 0.002) and were more commonly treated for aortic aneurysms (p = 0.001). In 15 patients (79%), the thrombi were located in the distal half of the FET stent-graft. Thrombus size was 18.9 mm (first quartile: 12.1; third quartile: 33.2). Distal embolisation occurred in 4 patients (21%) causing one in-hospital death caused by severe visceral ischaemia. Therapeutic anticoagulation was initiated in all patients. Overstenting with a conventional stent-graft placed within the FET stent-graft was the treatment in 2 patients (11%). Outcomes were comparable both groups. Female sex (p = 0.005; OR: 4.289) and an aortic aneurysm (p = 0.023; OR: 5.198) were identified as significant predictors for thrombus development.ConclusionPostoperative new thrombus formation within the FET stent-graft is a new, rare, but clinically highly relevant event. The embolisation of these thrombi can result in dismal postoperative outcomes. More research is therefore required to better identify patients at risk and improve perioperative treatment.
Project description:Behavior and innervation suggest a high tactile sensitivity of elephant trunks. To clarify the tactile trunk periphery we studied whiskers with the following findings. Whisker density is high at the trunk tip and African savanna elephants have more trunk tip whiskers than Asian elephants. Adult elephants show striking lateralized whisker abrasion caused by lateralized trunk behavior. Elephant whiskers are thick and show little tapering. Whisker follicles are large, lack a ring sinus and their organization varies across the trunk. Follicles are innervated by ~90 axons from multiple nerves. Because elephants don't whisk, trunk movements determine whisker contacts. Whisker-arrays on the ventral trunk-ridge contact objects balanced on the ventral trunk. Trunk whiskers differ from the mobile, thin and tapered facial whiskers that sample peri-rostrum space symmetrically in many mammals. We suggest their distinctive features-being thick, non-tapered, lateralized and arranged in specific high-density arrays-evolved along with the manipulative capacities of the trunk.
Project description:We describe our technique for total aortic arch replacement with stenting of the descending thoracic aorta allowing normothermic cardiopulmonary bypass and avoiding hypothermic circulatory arrest.Supplementary informationThe online version contains supplementary material available at 10.1007/s12055-023-01536-1.
Project description:Background and objectiveThe frozen elephant trunk (FET) allows a single-stage repair of complex arch pathologies due to its stented and non-stented hybrid prosthesis (HP) features. FET inherently has its own related complications including distal stent graft-induced new entry (dSINE), failure of aortic remodelling, endoleak, reintervention, and kinking of the stent. The aim of this narrative review is to discuss the latest evidence regarding the postoperative clinical outcomes of the FET procedure. Another aim is to provide an overview of results achieved using different FET devices on the global arch prostheses market.MethodsA comprehensive literature search was conducted using multiple electronic databases to identify and extract the relevant data and information.Key content and findingsThis review found that the literature reported a 5-12% mortality rate post-FET, with varying figures depending on the prosthesis type. Between 0-18.2% of patients developed dSINE, while 0.1-28% developed endoleak. Reintervention occurred in 0-28% of patients and the incidence of kinking has been quoted between 0-8% in the literature. Reporting aortic remodelling rates was challenging due to the lack of standardisation and various measurements reported; however, all studies included in this review reported relative increase in true lumen diameter, reduction in the false lumen diameter, and/or false lumen thrombosis.ConclusionsIn conclusion, FET can achieve a favourable postoperative profile in terms of survival, complications and aortic remodelling, and remains the gold-standard treatment for thoracic aortic pathologies implicating the arch and descending thoracic aorta.
Project description:The development of the frozen elephant trunk (FET) prosthesis has revolutionised how we treat some of the most complex aortic pathology, including in the emergency setting of acute type A aortic dissection. The design of the prosthesis is fundamental to the success of the procedure in combination with the surgeon’s skill in interpreting the pre-operative scan and procedural planning to juggling the technical aspects of the deployment and reimplantation of the supra-aortic vessels. Furthermore, organ protection strategies and techniques to reduce the complications of neurological and renal impairment are paramount. This article focuses on the Thoraflex Hybrid prosthesis including the evolution of the concept, design features unique to the device and surgical technique including fundamentals of sizing and implantation steps with illustrations. The Thoraflex Hybrid prosthesis provides an ergonomic and neat delivery system with a trusted gelatin coated surgical graft material making implantation and use as straightforward as possible. These features have meant that the device is a market leader in the field of FETs with outcome data and implant figures to support its efficacy globally. The success of the device is also reflected in the literature. For example, in the UK study from Mariscalco et al., the mortality of FET implantation in acute type A dissection, of which most were using the Thoraflex device, was only 12%. This is comparable to leading centres in Europe with the inherent advantage of improving long-term outcomes in addition. Of course, this strategy is not appropriate in all cases and precise judgement of when to deploy a FET in both the emergency and elective setting is key to achieving good outcomes.
Project description:Background. Two non-tuberculous mycobacterial strains, UM_3 and UM_11, were isolated from the trunk wash of captive elephants in Malaysia. As they appeared to be identical phenotypes, they were investigated further by conventional and whole genome sequence-based methods of strain differentiation. Methods. Multiphasic investigations on the isolates included species identification with hsp65 PCR-sequencing, conventional biochemical tests, rapid biochemical profiling using API strips and the Biolog Phenotype Microarray analysis, protein profiling with liquid chromatography-mass spectrometry, repetitive sequence-based PCR typing and whole genome sequencing followed by phylogenomic analyses. Results. The isolates were shown to be possibly novel slow-growing schotochromogens with highly similar biological and genotypic characteristics. Both strains have a genome size of 5.2 Mbp, G+C content of 68.8%, one rRNA operon and 52 tRNAs each. They qualified for classification into the same species with their average nucleotide identity of 99.98% and tetranucleotide correlation coefficient of 0.99999. At the subspecies level, both strains showed 98.8% band similarity in the Diversilab automated repetitive sequence-based PCR typing system, 96.2% similarity in protein profiles obtained by liquid chromatography mass spectrometry, and a genomic distance that is close to zero in the phylogenomic tree constructed with conserved orthologs. Detailed epidemiological tracking revealed that the elephants shared a common habitat eight years apart, thus, strengthening the possibility of a clonal relationship between the two strains.
Project description:The treatment of complex multi-segment disease concomitantly affecting the aortic arch and descending thoracic aorta is technically challenging. Until the 1990s, such extensive pathology was addressed by median sternotomy for aortic arch replacement followed by a traumatic thoraco-abdominal incision for reconstruction of the descending aorta as a single- or two-stage procedure. The advent of the conventional elephant trunk procedure by Borst in 1983 simplified the second-stage of this procedure by eliminating the need for clamping of the descending thoracic aorta. However, graft-related complications and the considerable inter-stage mortality were significant limitations associated with the conventional elephant trunk procedure. The emergence of endovascular technology and availability of dedicated arch prostheses culminated in a major paradigm change with the introduction of the frozen elephant trunk (FET) concept by Kato and colleagues in the mid-1990s. This one-stage procedure permits concurrent total aortic arch replacement with antegrade delivery of a descending aortic stent-graft which itself functions as a proximal landing zone to facilitate prospective endovascular intervention to treat residual or de novo disease in the more distal aorta. The frozen elephant technique has been applied extensively in acute aortic dissection to restore true lumen patency, occlude descending aortic intimal tears and promote false lumen thrombosis, as well as for chronic degenerative arch aneurysms. The Thoraflex Hybrid and E-vita Open are the two most common commercially available hybrid FET prostheses. This review aims to discuss the development, indications, surgical technique, currently available prostheses, clinical outcomes and future directions regarding the FET procedure.