Thoracic endovascular aortic repair (TEVAR) has emerged as a promising therapeutic alternative to conventional open aortic replacement but it requires suitable proximal and distal landing zones for stent-graft anchoring. Many aortic pathologies affect in the immediate proximity of the left subclavian artery (LSA) limiting the proximal landing zone site without proximal vessel coverage. In patients in whom the distance between the LSA and aortic lesion is too short, extension of the landing zone can be obtained by covering the LSA's origin with the endovascular stent graft (ESG). This manoeuvre has the potential for immediate and delayed neurological and vascular symptoms. Some authors, therefore, propose prophylactic revascularisation of the LSA by transposition or bypass, while others suggest prophylactic revascularisation only under certain conditions, and still others see no requirement for prophylactic revascularisation in anticipation of LSA ostium coverage. In this review about LSA revascularisation in TEVAR patients with coverage of the LSA, we searched the electronic databases MEDLINE and EMBASE historically until the end date of May 2010 with the search terms left subclavian artery, covering, endovascular, revascularisation and thoracic aorta. We have gathered the most complete scientific evidence available used to support the various concepts to deal with this issue. After a review of the current available literature, 23 relevant articles were found, where we have identified and analysed three basic treatment concepts for LSA revascularisation in TEVAR patients (prophylactic, conditional prophylactic and no prophylactic LSA revascularisation). The available evidence supports prophylactic revascularisation of the LSA before ESG LSA coverage when preoperative imaging reveals abnormal supra-aortic vascular anatomy or pathology. We further conclude that elective patients undergoing planned coverage of the LSA during TEVAR should receive prophylactic LSA transposition or LSA-to-left-common-carotid-artery (LCCA) bypass surgery to prevent severe neurological complications, such as paraplegia or brain stem infarction.
Purpose. Conventional surgical therapy of aortic arch aneurysms consists of aortic arch replacement requiring cardiopulmonary bypass and deep hypothermic circulatory arrest. This method is associated with significant morbidity and mortality, mainly due to neurologic complications and the sequelae of deep hypothermic circulatory arrest. Thus, it makes sense to work on developing less invasive surgical techniques.Description. Surgical aortic arch de-branching is required before the supra-aortic vessels can be safely covered by an endovascular stent graft. We describe how the supra-aortic vessels can best be revascularized, followed by complete coverage of the aortic arch with endovascular stent grafts.Evaluation. We hereby present our case selection criteria, preoperative work-up, and surgical approach for aortic arch de-branching with supra-aortic revascularization, followed by complete coverage of the aortic arch by endovascular stent grafting. This technique's safeguards and pitfalls are described for a cohort of 26 patients. We now describe how the BT and LCCA can best be revascularized, followed by complete coverage of the aortic arch with ESGs. Conclusions. Endovascular aortic arch repair after aortic arch de-branching has Technique PatientsWe performed EVAAR after aortic arch de-branching in 26 patients. We chose the endovascular approach over conventional aortic arch replacement with cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest in selected patients considered at high-risk due to multiple comorbidities and advanced age (Fig 1). Aortic arch pathology consisted of an aneurysm in 15 cases, and 6 patients presented a previous aortic dissection with development of an aortic arch aneurysm. A penetrating ulcer in the aortic arch was the underlying pathology in five cases. The ethics committees approved the study and waived the need for patient consent. Arch Vessel RevascularizationSurgery was initiated with an upper right, L-shaped, hemi-sternotomy to the third or fourth intercostal space. After exposing the ascending aorta, the supraaortic vessels were dissected and the innominate vein was encircled. Then the ascending aorta was tangen-
The increasing global prevalence of congestive heart failure is a major healthcare concern, accounting for a high morbidity rate worldwide. In particular, isolated right heart dysfunction after cardiotomy has a poor prognosis and is associated with a high mortality rate. The occurrence of postoperative right heart failure may develop in more than 40% of patients undergoing implantation of a left ventricular assist device (LVAD) and cardiac transplantation. To date, mechanical cardiac assistance in the form of VADs has become accepted as a therapeutic solution for end-stage patients when a donor heart is not available. However, right ventricular (RV) assistance is still in the early phase of development when compared with LVAD technology. State-of-the-art RVADs, both in clinical use and under development, are reviewed in this manuscript. Clinical RVADs include the extracorporeal pulsatile Abiomed BVS 5000 and AB5000, Thoratec PVAD, MEDOS VAD, BerlinHeart Excor, the percutaneous continuous flow CentriMag and TandemHeart systems, and the implantable Thoratec IVAD. Devices on the horizon, including the wear-free implantable DexAide and the minimally invasive Impella RD, are additionally reviewed. In addition to the current status of RV assistance, as well as the device categorization, the outlook and considerations for successful development of future RVADs were discussed.
We present a seldom seen case of Takotsubo cardiomyopathy (TCM) with concurrent obstructive coronary artery disease (OCAD) and its first case surgical experience. We propose that TCM and OCAD can coexist and that the presence of OCAD should not be an exclusion criterion for the diagnosis of TCM.
To date, ventricular assist devices (VADs) have become accepted as a therapeutic solution for end-stage heart failure patients when a donor heart is not available. Newer generation VADs allow for a significant reduction in size and an improvement in reliability. However, the invasive implantation still limits this technology to critically ill patients. Recently, expandable/deployable devices have been investigated as a potential solution for minimally invasive insertion. Such a device can be inserted percutaneously via peripheral vessels in a collapsed form and operated in an expanded form at the desired location. A common structure of such foldable pumps comprises a memory alloy skeleton covered by flexible polyurethane material. The material properties allow elastic deformation to achieve the folded position and withstand the hydrodynamic forces during operation; however, determining the optimal geometry for such a structure is a complex challenge. The numerical finite element method (FEM) is widely used and provides accurate structural analysis, but computation time is considerably high during the initial design stage where various geometries need to be examined. This article details a simplified two-dimensional analytical method to estimate the mechanical stress and deformation of memory alloy skeletons. The method was applied in design examples including two popular types of blade skeletons of a foldable VAD. Furthermore, three force distributions were simulated to evaluate the strength of the structures under different loading conditions experienced during pump operation. The results were verified with FEM simulations. The proposed two-dimensional method gives a close stress and deformation estimation compared with three-dimensional FEM simulations. The results confirm the feasibility of such a simplified analytical approach to reveal priorities for structural optimization before time-consuming FEM simulations, providing an effective tool in the initial structural design stage of foldable minimally invasive VADs.
Right ventricular assistance is still in the early phase of development compared to left ventricular assist device (LVAD) technology. In order to provide flexible pulmonary support and potentially reduce the known complications, we propose a minimally invasive right ventricular assist device (MIRVAD), located in the pulmonary artery (PA) and operating in series with the right ventricle (RV). The MIRVAD is an intra-arterial rotary blood pump containing a single axial impeller, which is not enclosed by a rigid housing but stent-fixed within the vessel. The impeller geometry has been designed with the assistance of analytical methods and computational fluid dynamics (CFD). The hydraulic performance of the impeller was evaluated experimentally with a customized test setup using blood synthetic medium (HES). The blade-tip clearance (BTC) was varied between 0.25-4.25 mm to evaluate the effect of different PA sizes on impeller performance. Furthermore, the Langrangian particle-tracking method was used to estimate the level of hemolysis and generate numerical blood damage indexes.The impeller design generated 25.6 mmHg for flow rates of 5 lpm at a speed of 6,000 rpm at the baseline condition, capable of providing sufficient support for the RV. The BTC presented a significant effect on the static pressure generation and the efficiency, but the operational range is suitable for most vessel sizes. The numerical results demonstrated a low risk of blood damage at the design point (mean Lagrangian damage index 2.6*10(-7)). The preliminary results have encouraged further impeller optimization and development of the MIRVAD.
Following successful repair of Type A dissection, late morbidity and mortality depend on the progression of residual chronic Type B dissection. To avoid the development of late aneurysms of the descending thoracic aorta, a persistent aortic false lumen around the stent-graft can be prevented by remodeling the thoracic aorta. Ten consecutive patients (mean age: 56 years) with acute Type A dissection underwent a "frozen elephant trunk operation" with the E-vita hybrid prosthesis, under deep hypothermic circulatory arrest, between October 2009 and April 2010. The thoracic aorta was restored to its original size. Computed tomography was used to size the aortic diameter. All patients survived and were routinely discharged. Postoperative computed tomography showed no remaining false lumen and no distal organ ischemia in any patient. No new neurological complication was recorded. Two patients suffered postoperative pulmonary arterial embolism; one underwent embolectomy. Restoration of the thoracic aorta is a safe procedure to close the false lumen during the primary operation for acute Type A dissection. However, the diameter of the stent should reflect the overall aortic size, independent of the diameter of the true lumen.
scite is a Brooklyn-based startup that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
334 Leonard St
Brooklyn, NY 11211
Copyright © 2023 scite Inc. All rights reserved.
Made with 💙 for researchers