Evaluating the haemodynamic performance of endografts for complex aortic arch repair

Thoracic endovascular aortic repair (TEVAR) of aortic aneurysms and dissections involving the arch has evolved over the last two decades. Compared to conventional surgical methods, endovascular repair offers a less invasive treatment option with lower risk and faster recovery. Endografts used in TEVAR vary in design depending on the procedure and application. Novel endografts (e.g., branched stent-graft) were developed to ensure perfusion of blood to the supra-aortic vessels, but their haemodynamic performance and long-term durability have not been adequately studied. This review focuses on the use of computational modelling to study haemodynamics in commercially available endografts designed for complex aortic arch repair. First, we summarise the currently adopted workflow for computational fluid dynamics (CFD) modelling, including geometry reconstruction, boundary conditions, flow models, and haemodynamic metrics of interest. This is followed by a review of recently (2010-present) published CFD studies on complex aortic arch repair, using both idealized and patient-specific models. Finally, we introduce some of the promising techniques that can be potentially applied to predict post-operative outcomes

Ultrasound-Guided Resuscitation in Open Aortic Surgery - The AORTUS Trial

Introduction: Major abdominal aortic surgery requires significant fluid resuscitation in the post-operative phase. Patients are at significant risk of perioperative morbidity and mortality which can be affected by the approach to post-operative fluid resuscitation. Point of care ultrasonography (POCUS) has evolved as a tool to perform whole-body assessments at the bedside to augment the physical exam and guide the resuscitation of the critically ill. This study will aim to explore the value of rigorous goal-directed resuscitation in aortic surgery using point of care ultrasonography (POCUS). Methods: In an open-label, randomized, feasibility trial we enrolled 17 patients to receive resuscitation guided by either POCUS or usual care Results: We observed that the trial protocol as designed met all of our pre-specified feasibility metrics Conclusion: The use of POCUS in guiding post-operative fluid resuscitation is feasible and utilizing this protocol to design a study powered to detect statistically significant differences in clinical outcomes is warranted

Abdominal Aortic Infections

Background. Abdominal aortic infections are dreaded disorders in vascular surgery, linked to high morbidity and mortality. Mycotic aneurysm as a primary infection of the abdominal aorta (MAAA) and an aortic graft infection (AGI) are different entities; however, due to bacterial presence in aorta and perivascular tissue, the principles of management are the same. Due to low incidence and complexity of disease, the high-quality evidence is lacking to define whether prosthetic aortic reconstructions in infectious conditions are utterly safe or whether biological reconstruction material should be preferred despite some shortcomings in durability. In complex abdominal surgery encompassing visceral aorta, prolonged aortic clamping above renal arteries is a risk factor for acute ischaemic kidney injury. In such situations, renal protection is recommended in order to avoid irreversible damage and renal replacement therapy. Aims. The aim of current study was to evaluate the infection resistance and durability of biological grafts as an aortic reconstruction material in abdominal aortic infections and to estimate the mortality after such reconstructions. Furthermore, efficacy of temporary axillo-renal bypass in prevention of renal ischaemic damage from major aortic surgery was estimated. Materials. The study comprises two parts. In the first part, 132 patients were analysed after being treated for aorto-iliac infections with arterial resection and reconstruction with a biological graft. Study I included patients treated due to AGI with femoral vein grafts, Study II included patients in whom the arterial infection was treated using cryopreserved venous allografts, and Study III included patients who were treated with various biological grafts for a primary aortic infection. The primary endpoints were postoperative mortality and reinfection rates, secondary endpoints were treatment-related mortality, overall mortality and graft reinterventions. During the second part of the study, (Study IV) patients who underwent temporary axillo-renal bypass during a major aortic intervention were retrospectively analysed. Outcome measures were postoperative kidney injury and 30-day mortality. Studies I, II and IV entailed retrospective analyses of patients treated at Helsinki University Hospital, while Study II was multicentre retrospective analysis of patients from six countries. Results. Sixty-four percent (64%, n=85) of the patients underwent surgery for an abdominal aortic infection with autologous femoral veins (FV), 17% (n=23) with cryopreserved venous allografts (CVA), 9% (n=12) with xenopericardial tube grafts, 5% (n=7) with cryopreserved arterial allografts, and 4% (n=5) with fresh arterial allografts. Most common indications for operation were aortic graft infection with an incidence of 51% (n=67) and mycotic abdominal aneurysm with 45% (n=60). The 30-day mortality was 9% for patients treated with FV for an AGI, 9% for patients treated for mixed infectious indications with cryopreserved venous allografts, and 5% for patients treated with various biological reconstructions due to MAAA,. The respective treatment-related mortality rates in these cohorts were 18%,13% and 9%. The reinfection rate was 2% (n=3) and 11% (n=14) of the grafts needed reinterventions at the mid-term follow-up, with stenotic lesions in femoral veins as the most common indication (n=9/14). Kaplan-Meier estimation of survival at 5 years was 59% (95% confidence interval, [CI] 43% – 73%) for patients treated with FV due to AGI and 71% (95% CI 52% –89%) for patients treated with mixed biological materials for MAAA. For patients treated with cryopreserved allografts for mixed indications, estimated survival at 2-years was 70% (95% CI 49% – 91%). Sixteen patients were operated with temporary axillo-renal bypass during aortic surgery. Despite short median renal ischaemia time of 24.5 minutes, 6 (38%) patients suffered acute kidney injury (AKI), of whom 4 had renal insufficiency preoperatively. One patient needed temporary renal replacement therapy, at one-month follow-up, however, renal function had returned to its baseline level or improved in all patients. The 30-day and in-hospital mortality was nil. Conclusions. Biological reconstruction material is infection resistant and reasonably durable in midterm analysis. Early postoperative and overall mortality rates are acceptable after treatment of such a complex entity as abdominal aortic infections. Furthermore, temporary axillo-renal bypass is safe and feasible in diminishing acute kidney injury during major aortic surgery.Primääri aortan infektio eli mykoottinen aneurysma ja aortan proteesi-infektio ovat vakavimpia tilanteita verisuonikirurgiassa, ja johtavat kuolemaan ilman hoitoa. Infektion parantamiseksi vierasmateriaali ja tulehtunut aorttaseinämä on pääsääntöisesti poistettava kokonaan ja raajojen verenkierto turvattava uudella verisuoniohiteella. Mikäli infektoitunut proteesi korjataan uudella proteesilla, on uusintainfektion vaara korkea. Tässä väitöskirjassa tutkitaan biologisten materiaalien toimivuutta aorttainfektioiden hoidossa sekä väliaikaisen munuaisohituksen toimivuutta akuutin munuaisen vajaatoiminnan ehkäisyssä potilailla, joilla aortta joudutaan pihdittämään munuaisvaltimon yläpuolelta korjauksen aikana. Väliaikaista ohitusta käyttämällä vältetään munuaisiskemia aorttapihdityksen aikana. Vuosina 2000-2018 tehdyistä biologisista ohituksista on kerätty seurantatiedot retrospektiivisesti HUS:ista; mykoottisten aneurysmien potilastiedot HUSin lisäksi viidestä eurooppalaisesta keskuksesta. Väliaikaisista munuaisohituksista on kerätty tiedot vuosilta 2007-2012. Tutkimuksessa arvoitiin biologisen materiaalin kestävyyttä tulehduksellisissa olosuhteissa, leikkauksenjälkeistä sairastavuutta ja pitkäaikaista eloonjäämistä. Munuaistoiminta arvioitiin ennen leikkausta ja sen jälkeen. Yhteensä tutkimusjakson aikana tehtiin yhteensä 132 biologista ohitusta aorttatulehdusten takia: rekonstruktiomateriaalina oli potilaan oma syvälaskimo 85:ssa tapauksessa, pakastettu elinluovuttajan laskimo 23:ssa tapauksessa, pakastettu elinluovuttajan valtimografti 7:ssa tapauksessa, tuore luovuttajan valtimo 5:ssa tapauksessa ja kaupallisesta härän perikardista käsin tehty tuubigrafti 12:ssa tapauksessa. Uusinta-infektioita esiintyi 2%:lla ja keskipitkän seurannan aikana 11%:lle tehtiin ohitteen korjaustoimeenpide. Ohiteen repeytymisestä johtuvia kuolemia ei ollut seuranta-aikana. Leikkauksen jälkeinen kuolleisuus oli 5%-13% kolmessa eri tutkimuksessa ja pitkäaikainen eloonjääminen 5 vuoden kohdalla 71%-59%. Leikkauksen jälkeinen munuaisten vajaatoiminta ilmaantui 6/16 potilaalle, mutta kuukauden kuluttua leikkauksesta munuaistoiminta oli palautunut lähtötasoon tai parantunut kaikissa tapauksissa. Yksikään potilas ei kuollut leikkauksen jälkeisessä vaiheessa väliaikaisen munuaisohituksen jälkeen. Tutkimuksemme mukaan biologiset ohitukset ovat infektioresistentteja ja suhteellisen kestäviä aortan korjausmateriaaleja infektio-olosuhteissa. Kuolleisuus on leikkauksen jälkeen merkittävää, mutta ottaen huomioon taudin vakavuus ja erittäin korkea mortaliteetti ilman leikkaushoitoa, kuolleisuus on hyväksyttävä sekä lyhyellä että pitkällä aikavälillä. Väliaikainen munuaisohite on tehokas tapa välttää munuaisten vajatoiminnan kehittymistä tai pahenemista haastavissa aorttaleikkauksissa

Cognitive outcome of aneurysmal subarachnoid haemorrhage after clipping or coiling : a comparative post intervention study in a hospital population

Subarachnoid haemorrhage secondary to ruptured cerebral aneurysm and clipping are associated with substantial morbidity and mortality. Despite favourable neurological outcomes, many patients report persistent cognitive and emotional deficits post intervention. To compare cognitive and quality of life outcomes in patients with ruptured aneurysmal subarachnoid haemorrhage treated with surgical clipping or endovascular coiling. Twenty-four patients with aneurysmal subarachnoid haemorrhage treated by clipping or coiling were retrospectively assessed by use of a battery of cognitive tests and a quality of life questionnaire. All patients had favourable grades on admission, that is, WFNS <= 2 and favourable neurological grades on discharge, that is, GOS <=2. treated with surgical clipping or endovascular coiling. Patients in the two treatment groups were matched on age, years of education and on premorbid IQ. The two groups were further matched on time from intervention to assessment and number of treatments. The cognitive performance of the treatment groups was compared to hospitalised controls, matched for age, years of education and premorbid IQ. Comparison of cognitive outcome between the two groups indicated a trend towards poorer outcome in the surgical group which achieved significance on six test measures. There were no significant differences with respect to the quality of life measure. Patients surviving aneurysmal subarachnoid haemorrhage are likely to suffer from a 'subarachnoid-induced encephalopathy' which appears to be more aggravated by the invasive nature of surgery, compared to endovascular coiling, as demonstrated by the poorer cognitive performance ofthe clipping patients

Abstracts - SA Heart Congress 2016

Index of abstracts: alphabetical listing of first authors

Data Mining and Associated Analytical Tools as Decision Aids for Healthcare practitioners in Vascular Surgery

Vascular surgery is an increasingly data rich speciality. Planning treatment and assessing outcomes are highly dependent on objective assessment of number of imaging modalities including duplex ultrasound, CT scans and angiograms which are almost exclusively digitally created stored and accessed. Developments such as the national vascular registry mean that treatment outcomes are recorded scrutinised electronically. The widespread availability of data which is collected electronically and stored for future clinical use has created the opportunity to examine the efficacy of investigations and treatments in a way which has hitherto not been possible. In addition, new computational methods for data analysis have provided the opportunity for the clinicians and researchers to utilise this data to address pertinent clinical questions