Cardiac remodelling following thoracic endovascular aortic repair for descending aortic aneurysms

Computational Fluid-Structure Interaction in Microfluidics

Micro elastofluidics is a transformative branch of microfluidics, leveraging the fluid-structure interaction (FSI) at the microscale to enhance the functionality and efficiency of various microdevices. This review paper elucidates the critical role of advanced computational FSI methods in the field of micro elastofluidics. By focusing on the interplay between fluid mechanics and structural responses, these computational methods facilitate the intricate design and optimisation of microdevices such as microvalves, micropumps, and micromixers, which rely on the precise control of fluidic and structural dynamics. In addition, these computational tools extend to the development of biomedical devices, enabling precise particle manipulation and enhancing therapeutic outcomes in cardiovascular applications. Furthermore, this paper addresses the current challenges in computational FSI and highlights the necessity for further development of tools to tackle complex, time-dependent models under microfluidic environments and varying conditions. Our review highlights the expanding potential of FSI in micro elastofluidics, offering a roadmap for future research and development in this promising area.

Patient-Specific Haemodynamic Analysis of Virtual Grafting Strategies in Type-B Aortic Dissection: Impact of Compliance Mismatch

INTRODUCTION

Compliance mismatch between the aortic wall and Dacron Grafts is a clinical problem concerning aortic haemodynamics and morphological degeneration. The aortic stiffness introduced by grafts can lead to an increased left ventricular (LV) afterload. This study quantifies the impact of compliance mismatch by virtually testing different Type-B aortic dissection (TBAD) surgical grafting strategies in patient-specific, compliant computational fluid dynamics (CFD) simulations.

MATERIALS AND METHODS

A post-operative case of TBAD was segmented from computed tomography angiography data. Three virtual surgeries were generated using different grafts; two additional cases with compliant grafts were assessed. Compliant CFD simulations were performed using a patient-specific inlet flow rate and three-element Windkessel outlet boundary conditions informed by 2D-Flow MRI data. The wall compliance was calibrated using Cine-MRI images. Pressure, wall shear stress (WSS) indices and energy loss (EL) were computed.

RESULTS

Increased aortic stiffness and longer grafts increased aortic pressure and EL. Implementing a compliant graft matching the aortic compliance of the patient reduced the pulse pressure by 11% and EL by 4%. The endothelial cell activation potential (ECAP) differed the most within the aneurysm, where the maximum percentage difference between the reference case and the mid (MDA) and complete (CDA) descending aorta replacements increased by 16% and 20%, respectively.

CONCLUSION

This study suggests that by minimising graft length and matching its compliance to the native aorta whilst aligning with surgical requirements, the risk of LV hypertrophy may be reduced. This provides evidence that compliance-matching grafts may enhance patient outcomes.

Ultrasound elastography to quantify average percent pressure-normalized strain reduction associated with different aortic endografts in 3D-printed hydrogel phantoms

Objective

Strain has become a viable index for evaluating abdominal aortic aneurysm stability after endovascular aneurysm repair (EVAR). In addition, literature has shown that healthy aortic tissue requires a degree of strain to maintain homeostasis. This has led to the hypothesis that too much strain reduction conferred by a high degree of graft oversizing is detrimental to the aneurysm neck in the seal zone of abdominal aortic aneurysms after EVAR. We investigated this in a laboratory experiment by examining the effects that graft oversizing has on the pressure-normalized strain (ε ρ + ¯ /pulse pressure [PP]) reduction using four different infrarenal EVAR endografts and our ultrasound elastography technique. Approximate graft oversizing percentages were 20% (30 mm phantom-graft combinations), 30% (28 mm phantom-graft combinations), and 50% (24 mm phantom-graft combinations).

Methods

Axisymmetric, 10% by mass polyvinyl alcohol phantoms were connected to a flow simulator. Ultrasound elastography was performed before and after implantation with the four different endografts: (1) 36 mm polyester/stainless steel, (2) 36 mm polyester/electropolished nitinol, (3) 35 mm polytetrafluoroethylene (PTFE)/nitinol, and (4) 36 mm nitinol/polyester/platinum-iridium. Five ultrasound cine loops were taken of each phantom-graft combination. They were analyzed over two different cardiac cycles (end-diastole to end-diastole), yielding a total of 10 maximum mean principal strain (ε ρ + ¯ ) values.ε ρ + ¯ was divided by pulse pressure to yield pressure-normalized strain (ε ρ + ¯ /PP). An analysis of variance was performed for graft comparisons. We calculated the average percentε ρ + ¯ /PP reduction by manufacturer and percent oversizing. These values were used for linear regression analysis.

Results

Results from one-way analysis of variance showed a significant difference inε ρ + ¯ /PP between the empty phantom condition and all oversizing conditions for all graft manufacturers (F(3, 56) = 106.7 [graft A], 132.7 [graft B], 106.5 [graft C], 105.7 [graft D], P < .0001 for grafts A-D). There was a significant difference when comparing the 50% condition with the 30% and 20% conditions across all manufacturers by post hoc analysis (P < .0001). No significant difference was found when comparing the 20% and 30% oversizing conditions for any of the manufacturers or when comparingε ρ + ¯ /PP values across the manufacturers according to percent oversize. Linear regression demonstrated a significant positive correlation between the percent graft oversize and the all-graft average percentε ρ + ¯ /PP reduction (R 2  = 0.84, P < .0001).

Conclusions

This brief report suggests that a 10% increase in graft oversizing leads to an approximate 5.9% reduction inε ρ + ¯ /PP on average. Applied clinically, this increase may result in increased stiffness in axisymmetric vessels after EVAR. Further research is needed to determine if this is clinically significant.

Emergency and Compassionate Use of a Novel Ascending Endograft for Ascending and Arch Aortic Pathology

PURPOSE

Patients with complicated ascending aortic pathology, including patients with acute type A aortic dissection may be at extreme risk for open repair. Thoracic endovascular aortic repair (TEVAR), infrequently used for the ascending aorta, may be considered an alternative in this setting. We describe early results for emergency and compassionate (E&C) use of a novel endograft, specifically designed for use to treat pathology of the ascending aorta.

MATERIALS AND METHODS

This case series evaluated 19 patients (mean age, 68.84±13.12 years; 57.9% female) treated with ascending TEVAR for acute and chronic acute (4), subacute (1), or chronic (1) aortic dissection or pseudoaneurysm (13). Six of the 19 patients (31.5%) were treated under compassionate use and 13 patients (68.4%) were treated under the emergency use exemption. Ten patients (52.6%) received additional devices to extend treatment into the arch and descending aorta.

RESULTS

Device delivery was achieved in all patients (100%). Thirty-day mortality and stroke occurred in 3 patients (15.8%) and in 1 patient (5.3%), respectively. In 1 patient (5.3%), with an Unanticipated Adverse Device Event, the aorta ruptured when the endograft eroded into the adventitial portion of dissection site at the posterior aspect of the ascending wall. Devices were explanted in 2 patients (10.5%), 353 and 610 days after the index procedure, respectively. Six patients had endoleaks (31.6%), including type I (n=2, 10.5%), type II endoleaks (n=3, 15.8%), and indeterminate endoleak (n=1, 5.3%).

CONCLUSIONS

Delivery and deployment of a novel ascending thoracic stent graft with or without an additional branched arch extension is feasible in patients with complex anatomy and pathology, including acute aortic dissection and pseudoaneurysm. Additional experience with this novel device will further refine the patient population most suitable for endovascular ascending aortic repair for these pathologies.

CLINICAL IMPACT

This study describes a novel stent graft specifically designed for treatment of ascending aortic pathology, including acute type A dissection. The patients described in this series constituted a group outside the formal US FDA sponsored clinical trial, and were those accepted as part of an emergency and compassionate use basis.

Endovascular aortic repair impact on myocardial contractility: A prospective study

BACKGROUND

This study aimed to estimate if the altered sphygmic wave transmission may affect the left ventricular (LV) contractile function in patients undergoing endovascular aortic repair (EVAR).

METHODS

A prospective single-centre study was carried out on consecutive patients undergoing EVAR for abdominal aortic aneurysm. A preoperative and 6-month single photon emission computed tomography (SPECT) with arterial stiffness measurement were performed to evaluate variations in pressure wave curve and myocardial perfusion parameters.

RESULTS

From 2018 to 2020 a total of 16 patients were included in the study. Among the parameters evaluated, we found a measurable reduction of the reflected wave transit time from pre- to postoperative period, for both stress (115.13 ± 7.2 ms-111.1 ± 7.0 ms, p = .08) and rest SPECT acquisitions (115.3 ± 6.2 ms-112.2 ± 5.6 ms, p = .1). Unidirectional increase of both LV end-systolic volume (34 ± 9 mL-39 ± 8 mL, p = .02) and end-diastolic volume (85 ± 34 mL-89 ± 29 mL, p = .6) was also observed. Lastly, the ratio between the end-systolic pressure and the end-systolic volume (maximal systolic myocardial stiffness) decreased from 3.6 ± 1.5 mmHg/mL to 2.66 ± .74 mmHg/mL (p = .03).

CONCLUSIONS

Our data showed that EVAR induced an altered transmission of the sphygmic wave associated with an early LV contractile impairment.

Early Outcomes on Triple-Branch Arch Device With Retrograde Left Common Carotid Branch: A Case Series

INTRODUCTION

Endovascular aortic arch repair using multibranch devices has been applied in patients considered at high risk for open repair. The aim of this case series was to report the early outcomes in patients managed with a new design 3 branch arch custom-made device, including a retrograde left common carotid artery (LCCA) branch.

METHODS

The Preferred Reporting Of CaSe Series in Surgery (PROCESS) guidelines were followed. All consecutive patients undergoing endovascular repair of an aortic arch lesion with a custom-made triple-branch device, including a retrograde LCCA branch (Cook Medical, Bloomington, IN, USA), between October 27, 2022, and February 28, 2023, were included. The presence of an arch aneurysm (degenerative or post-dissection) with diameter ≥55 mm and high risk for a conventional open repair set the indication for treatment. The primary outcomes were technical success and mortality at 30 days. Early morbidity and reinterventions were considered as secondary outcomes.

RESULTS

Eight elective patients (87.5% men, mean age 72.3±27.0 years) were included. Five of them (62.5%) had undergone a previous ascending aorta repair of an acute type A aortic dissection. All patients were asymptomatic, except one, with left recurrent laryngeal nerve compression. The mean maximum aortic diameter was 70.4±21.0 mm. Percutaneous femoral and axillary access was used in all cases except three in which a cut down for right carotid access was performed. Technical success was 100%. Femoral access to the LCCA and implantation of the bridging stent was performed without technical challenges. No death nor cerebrovascular event was recorded during the 30 day follow-up. Five patients (62.5%) presented major complications, 3 related to access needing reintervention and the remaining related to congestive heart failure (CHF), which were managed successfully with medical treatment. Follow-up (range 1-4 month) was uneventful, except for one patient who presented a secondary type Ia endoleak.

CONCLUSIONS

According to our early experience, the presence of a retrograde branch facilitated the revascularization of the LCCA through femoral access, decreasing the risk of cerebrovascular morbidity. Further analyses with longer follow-up are needed to evaluate the safety and efficacy of the device.

CLINICAL IMPACT

Data arising mainly from the retrograde branch for the revascularization of the LSA are encouraging from a variety of devices. The premiminary experience with a triple-branched arch device, with a retrograde branche for the LSA but also for the LCCA, was associated with no 30 day mortality and 100% technical success.The device's design allowed swift catheterization and completion of the LCCA revascularization using femoral access exclusively.

Ascending Aortic Endograft and Thoracic Aortic Deformation After Ascending Thoracic Endovascular Aortic Repair

PURPOSE

We aim to quantify multiaxial cardiac pulsatility-induced deformation of the thoracic aorta after ascending thoracic endovascular aortic repair (TEVAR) as a part of the GORE ARISE Early Feasibility Study.

MATERIALS AND METHODS

Fifteen patients (7 females and 8 males, age 73±9 years) with ascending TEVAR underwent computed tomography angiography with retrospective cardiac gating. Geometric modeling of the thoracic aorta was performed; geometric features including axial length, effective diameter, and centerline, inner surface, and outer surface curvatures were quantified for systole and diastole; and pulsatile deformations were calculated for the ascending aorta, arch, and descending aorta.

RESULTS

From diastole to systole, the ascending endograft exhibited straightening of the centerline (0.224±0.039 to 0.217±0.039 cm^-1, p<0.05) and outer surface (0.181±0.028 to 0.177±0.029 cm^-1, p<0.05) curvatures. No significant changes were observed for inner surface curvature, diameter, or axial length in the ascending endograft. The aortic arch did not exhibit any significant deformation in axial length, diameter, or curvature. The descending aorta exhibited small but significant expansion of effective diameter from 2.59±0.46 to 2.63±0.44 cm (p<0.05).

CONCLUSION

Compared with the native ascending aorta (from prior literature), ascending TEVAR damps axial and bending pulsatile deformations of the ascending aorta similar to how descending TEVAR damps descending aortic deformations, while diametric deformations are damped to a greater extent. Downstream diametric and bending pulsatility of the native descending aorta was muted compared with that in patients without ascending TEVAR (from prior literature). Deformation data from this study can be used to evaluate the mechanical durability of ascending aortic devices and inform physicians about the downstream effects of ascending TEVAR to help predict remodeling and guide future interventional strategies.

CLINICAL IMPACT

This study quantified local deformations of both stented ascending and native descending aortas to reveal the biomechanical impact of ascending TEVAR on the entire thoracic aorta, and reported that the ascending TEVAR muted cardiac-induced deformation of the stented ascending aorta and native descending aorta. Understanding of in vivo deformations of the stented ascending aorta, aortic arch and descending aorta can inform physicians about the downstream effects of ascending TEVAR. Notable reduction of compliance may lead to cardiac remodeling and long-term systemic complications. This is the first report which included dedicated deformation data regarding ascending aortic endograft from clinical trial.

Efficacy and Safety of Exercise Testing and Rehabilitation for Aortic Dissection Patients: A SCOPING REVIEW

OBJECTIVE

Although physical exercise has established benefits for long-term cardiovascular health, concern regarding further aortic events has limited the evidence for exercise among aortic dissection (AD) patients. The objective was to perform a scoping review of the current concepts and gaps in the literature regarding the benefit and safety of cardiovascular testing and rehabilitation among post-AD patients.

REVIEW METHODS

A scoping review of the literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Eligibility criteria included any studies with AD in relation to exercise rehabilitation or testing and physical or mental health. Electronic databases were queried for relevant studies (last queried, November 1, 2021).

RESULTS

Six observational studies were included with a total of 381 patients with AD, all of whom underwent surgical intervention. Study heterogeneity prevented data synthesis and a formal systematic review, although four dominant themes emerged: cardiovascular-related outcomes, aorta-related outcomes, quality of life (QoL), and serious adverse events. Patients with AD have reduced baseline physical capacity and QoL. Rehabilitation programs may increase both physical status and QoL. Rates of serious adverse rates are minimal yet poorly defined.

CONCLUSIONS

Within the context of apparent benefits from cardiovascular testing and rehabilitation for patients with AD who have undergone intervention, this scoping review highlights the need for increased comparative research specific to exercise among patients with AD and outcomes such as mortality and reinterventions.

Impact of thoracic endovascular aortic repair on aortic biomechanics: Integration of in silico and ex vivo analysis using porcine model

Thoracic endovascular aortic repair (TEVAR) is widespread in clinical practice for treating aortic diseases but it has relevant systemic complications, such as increase of the cardiac workload due to post-TEVAR aortic stiffening, and local issues such as re-entry tears due to the tissue damage caused by endograft interaction. The present study aims to elucidate these aortic biomechanical mechanisms by coupling ex vivo and in silico analysis. By ex vivo tests, the pulse wave velocity before and after TEVAR is measured. Uni-axial tensile tests are performed to measure regional mechanical response of tissue samples, supplied as input data for the in silico analysis. Numerical analysis is finally performed to compute the wall stress induced by the stent-graft deployment and the arterial pressurization. The ex vivo results highlight an increase of baseline PWV by a mean .78 m/s or 12% after TEVAR with a 100 mm stent-graft (p <.013). In the in silico analysis, the average von Mises stress in the landing zone increases of about 15% and 20% using, respectively stent-graft with radial oversizing of 10% and 20%. This work shows the effectiveness of integrated framework to analyze the biomechanical post TEVAR mechanisms. Moreover, the obtained results quantify the effect of prosthesis selection on the stiffening of the aorta after TEVAR and on the local increase of the aortic wall stress that is proportional to the stent-graft oversizing.

Echocardiographic Changes in Cardiac Function After Thoracic Endovascular Aortic Repair: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence suggests thoracic stent grafts increase the aortic stiffness postimplantation. Our objective was to examine the effect of thoracic aortic stenting on heart function, as demonstrated with echocardiography.

METHODS

We considered nonrandomized studies examining echocardiographic parameters (left ventricle ejection fraction (LVEF), left ventricle end-diastolic (LVED) and end-systolic diameter (LVESD), posterior wall thickness (LVPWT), interventricular septal thickness (IVST), mass, and mass index) pre and poststent graft implantation in patients with thoracic aortic diseases (aneurysm, dissection, and blunt injury). MEDLINE and CENTRAL were searched (up to March 2021) for eligible studies. The National Institutes of Health Quality Assessment Tool was used for risk of bias assessment. Echocardiographic data pre and postimplantation were compared using the pooled standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Four studies were included in the meta-analysis. Three of the studies were judged to be "good" quality and one "fair". Nonsignificant differences pre and postimplantation were found for ejection fraction (SMD = -0.53, 95% CI = -1.8 to 0.728, P = 0.406), IVST (SMD = -0.79, 95%, CI = -3.25 to 1.66, P = 0.52), EDD (SMD = -0.10, 95% CI = -0.48 to 0.28, P = 0.60), ESD (SMD = -0.66, 95% CI = -2.35 to 1.02, P = 0.44), and PWT (SMD = -2.20, 95% CI = -5.89 to 1.47, P = 0.24). A trend toward an increase in mass postimplantation was found (SMD = 0.28, 95%, CI = -0.03 to 0.60, P = 0.08), but there was no significant difference in mass index (SMD = 0, 95%, CI = -0.195 to 0.195, P = 1).

CONCLUSIONS

Thoracic aortic stenting does not appear to significantly impact cardiac physiology as indicated by echocardiographic parameters.

Comparison of Two Generations of Thoracic Aortic Stent Grafts and Their Impact on Aortic Stiffness in an Ex Vivo Porcine Model

Objective

Little is known about the cardiovascular changes after TEVAR and regarding the impact on aortic stiffness for different stent graft generations specifically, following changes in device design. The present study evaluated the stent graft induced aortic stiffening of two generations of the Valiant thoracic aortic stent graft.

Methods

This was an ex vivo porcine investigation using an experimental mock circulatory loop. Thoracic aortas of young healthy pigs were harvested and connected to the mock circulatory loop. At a 60 bpm heart rate and stable mean arterial pressure, baseline aortic characteristics were obtained. Pulse wave velocity (PWV) was calculated before and after stent graft deployment. Paired and independent sample t tests or their non-parametric alternatives were performed to test for differences where appropriate.

Results

Twenty porcine thoracic aortas were divided into two equal subgroups, in which a Valiant Captivia or a Valiant Navion stent graft was deployed. Both stent grafts were similar in diameter and length. Baseline aortic characteristics did not differ between the subgroups. Mean arterial pressure values did not change after either stent graft, while pulse pressures increased statistically significantly after Captivia (mean 44 ± 10 mmHg to 51 ± 13 mmHg, p = .002) but not after Navion. Mean baseline PWV increased after both Captivia (4.4 ± 0.6 m/s to 4.8 ± 0.7 m/s, p = .007) and Navion (4.6 ± 0.7 m/s to 4.9 ± 0.7 m/s, p = .002). There was no statistically significant difference in the mean percentage increase in PWV for either subgroup (8 ± 4% vs. 6 ± 4%, p = .25).

Conclusion

These experimental findings showed no statistically significant difference in the percentage increase of aortic PWV after either stent graft generation and confirm that TEVAR increases aortic PWV. As a surrogate for aortic stiffness, this calls for further improvements in future thoracic aortic stent graft designs regarding device compliance.

Left ventricular remodeling following aortic root and ascending aneurysm repair

Objective

Adverse left ventricular remodeling due to a mismatch between stiffness of native aortic tissue and current polyester grafts may be under-recognized. This study was conducted to evaluate the impact of proximal aortic replacement on adverse remodeling of the left ventricle.

Materials and methods

All aortic root and ascending aortic aneurysm patients were identified (n = 2,001, 2006–2019). The study cohort consisted of a subset of patients (n = 98) with two or more electrocardiogram (ECG)-gated CT angiograms, but without concomitant aortic valve disease or bicuspid aortic valve, connective tissue disease, acute aortic syndrome or prior history of aortic repair or mitral valve surgery. LV myocardial mass was measured from CT data and indexed to body surface area (LVMI). The study cohort was divided into a surgery group (n = 47) and a control group; optimal medical therapy group (OMT, n = 51).

Results

The mean age was 60 ± 11 years (80% male). Beta-blocker use was significantly more frequent in the surgery group (89 vs. 57%, p &lt; 0.001), whereas, all other antihypertensive drugs were more frequent in the OMT group. The average follow-up was 9.1 ± 4.0 months for the surgery group and 13.7 ± 6.3 months for the OMT group. Average LVMI at baseline was similar in both groups (p = 0.934). LVMI increased significantly in the surgery group compared to the OMT group (3.7 ± 4.1 vs. 0.6 ± 4.4 g/m2, p = 0.001). Surgery, baseline LVMI, age, and sex were found to be independent predictors of LVMI increased on multivariable analysis.

Conclusion

Proximal aortic repair with stiff polyester grafts was associated with increased LV mass in the first-year post-operative and may promote long-term adverse cardiac remodeling. Further studies should be considered to evaluate the competing effects of aortic aneurysm related mortality against risks of long-term graft induced aortic stiffening and the potential implications on current size thresholds for intervention.

Postoperative management in patients with complex aortic aneurysms

Patients with complex aortic aneurysms (CAA) are often high risk due to advanced age and widespread atherosclerosis affecting numerous vascular territories. Therefore, a thorough perioperative evaluation is needed prior to performing in any type of aortic repair, regardless of whether an endovascular or open surgical approach is selected. Because these operations are technically demanding and often result in end organ ischemia, it is not surprising that complex aortic repair carries significant risk of morbidity and mortality. Disabling complications such as dialysis, major stroke and paraplegia constitute the main limitation of complex aortic repair. The aim of this article was to review postoperative management to mitigate complications after CAA repair.

Data-driven computational models of ventricular-arterial hemodynamics in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a complex disease involving increased resistance in the pulmonary arteries and subsequent right ventricular (RV) remodeling. Ventricular-arterial interactions are fundamental to PAH pathophysiology but are rarely captured in computational models. It is important to identify metrics that capture and quantify these interactions to inform our understanding of this disease as well as potentially facilitate patient stratification. Towards this end, we developed and calibrated two multi-scale high-resolution closed-loop computational models using open-source software: a high-resolution arterial model implemented using CRIMSON, and a high-resolution ventricular model implemented using FEniCS. Models were constructed with clinical data including non-invasive imaging and invasive hemodynamic measurements from a cohort of pediatric PAH patients. A contribution of this work is the discussion of inconsistencies in anatomical and hemodynamic data routinely acquired in PAH patients. We proposed and implemented strategies to mitigate these inconsistencies, and subsequently use this data to inform and calibrate computational models of the ventricles and large arteries. Computational models based on adjusted clinical data were calibrated until the simulated results for the high-resolution arterial models matched within 10% of adjusted data consisting of pressure and flow, whereas the high-resolution ventricular models were calibrated until simulation results matched adjusted data of volume and pressure waveforms within 10%. A statistical analysis was performed to correlate numerous data-derived and model-derived metrics with clinically assessed disease severity. Several model-derived metrics were strongly correlated with clinically assessed disease severity, suggesting that computational models may aid in assessing PAH severity.

TEVAR and EVAR, the unknown knowns of the cardiovascular hemodynamics; and the immediate and long-term consequences of fabric material on major adverse clinical outcome

This review discusses the impact of endovascular aneurysm repair on cardiovascular (CV) hemodynamics and the role of stent-graft material, i.e., polytetrafluoroethylene (PTFE) vs. polyester in post-procedural outcomes. Endovascular aneurysm repair has been widely employed in the last decades for thoracic and abdominal aneurysm repair. However, aortic endografts are stiff and alter the native flow hemodynamics. This failure to simulate the native aorta could lead to added strain on the heart, manifesting as increased left ventricular strain, higher pulse pressure, and congestive heart failure later. This could result in adverse CV outcomes. Also, evidence is mounting to support the implication of stent-graft materials, i.e., PTFE vs. polyester, in adverse post-procedural outcomes. However, there is an absence of level one evidence. Therefore, the only way forward is to plan and perform a randomised controlled trial to demonstrate the alterations in the CV hemodynamics in the short and long run and compare the available stent-graft materials regarding procedural and clinical outcomes. We believe the best solution, for now, would be to reduce the stented length of the aorta. At the same time, in the longer term, encourage continuous improvement in stent-graft materials and design.

The contemporary design of endovascular aneurysm stent-graft materials: PTFE versus polyester

Endovascular aneurysm repair of the abdominal aorta (EVAR) and of the thoracic aorta (TEVAR) have revolutionised therapeutic strategies in the management of aortic pathology, and endovascular repair is now an established and attractive alternative to open surgical repair (OSR) due to its superior short-term safety profile. However, opinions are divided regarding its long-term cost-effectiveness, which is reflected in the controversial NICE guidelines on abdominal aortic aneurysm (AAA) repair published in 2018, which advised against EVAR for elective aortic repair due to high secondary intervention rates and resultant associated costs. There is no doubt that OSR continues to have a valuable role to play in aortic repair, but it is not universally applicable, especially in older and sicker patients. Therefore, we should not dismiss EVAR and TEVAR without examining the reasons for long-term failure, and the most obvious starting point is stent graft material properties. Polytetrafluoroethylene (PTFE) and polyester are the two most common stent-graft materials; however, there has been no objective comparison of PTFE and polyester stent-graft post-procedural outcomes in EVAR and TEVAR, or even OSR. This lack of definitive data on different stent-graft materials and their configuration necessitates a comprehensive review to elucidate the post-procedural outcome in terms of endograft failure, cardiovascular events, and aortic-related mortality and morbidity.

Aortic Biomechanics and Clinical Applications

The aorta contributes to cardiovascular physiology and function. Understanding biomechanics in health, disease, and after aortic interventions will facilitate optimization of perioperative patient care.

High risk of early and late cardiovascular events after endovascular aortic aneurysm repair

OBJECTIVE

The objective of this population-based study was to analyze short- and long-term major adverse cardiovascular events (MACE) after endovascular repair of ruptured or non-ruptured thoracic (TAA) and abdominal aortic aneurysms (AAA).

METHODS

Nationwide retrospective registry study including all patients that underwent endovascular repair (thoracic endovascular aortic repair, TEVAR; abdominal endovascular aneurysm repair, EVAR) for non-ruptured/intact (iAAA/iTAA) or ruptured (rAAA/rTAA) abdominal or thoracic aneurysms between 2000 and 2018. The primary outcome was a composite of cardiovascular death, stroke, or myocardial infarction (MACE).

RESULTS

There were 8641 patients with TAA and AAA; 634 TEVAR procedures [iTAA 488; rTAA 146] and 8007 EVAR procedures [iAAA 7071; rAAA 936] were performed. MACE incidence at 90-day after TEVAR for iTAA was 10.2% and for rTAA 26.7% [HR 3.02, 95% CI 1.99-4.6]; MACE at 90-day after EVAR for iAAA was 3.7% and for rAAA 26.9 % [HR 8.5, 95% CI: 7.16-10.11]. There was a higher cumulative incidence of MACE at 90-day after TEVAR for iTAA compared to EVAR for iAAA [HR 2.82, 95% CI 2.09-3.82] but no difference between the procedures after ruptured aneurysm repair. The median follow-up time was 3.28 years [IQR 1.31-5.94]. There was no long-term difference in MACE between EVAR and TEVAR after ruptured [90d-5y: HR 1.14, 95% CI 0.76-1.71; 5y-10y: HR 0.78, 95% CI 0.31-1.96] or intact [90d-5y: HR 1.19, 95% CI 0.97-1.46; 5y-10y: HR 0.82, 95% CI 0.56-1.21] aneurysm repair. Female gender had higher long-term incidence of MACE after intact [HR 1.14, 95% CI 1.03-1.27] and ruptured [HR 1.36, 95% CI 1.12-1.65] endovascular aortic aneurysm treatment. After intact aneurysms repair; age [HR 1.05, 95% CI 1.04-1.05], history of angina pectoris [HR 1.19, 95% CI 1.08-1.32], heart failure [HR 1.90, 95% CI 1.69-2.13], and stroke [HR 1.33, 95% CI 1.15-1.53] were associated with MACE.

CONCLUSIONS

This nationwide cohort study demonstrated still a high risk of early and late cardiovascular events after endovascular aortic repair. Comprehensive strategies for postoperative cardiovascular disease prevention may here be needed.

Endovascular versus conventional open surgical repair for thoracoabdominal aortic aneurysms

BACKGROUND

Thoracoabdominal aortic aneurysms (TAAAs) are a life-threatening condition which remain difficult to treat. Endovascular and open surgical repair (OSR) provide treatment options for patients, however, due to the lack of clinical trials comparing these, the optimum treatment option is unknown.

OBJECTIVES

To assess the effectiveness and safety of endovascular repair versus conventional OSR for the treatment of TAAAs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 26 April 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations.

SELECTION CRITERIA

We considered all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing endovascular repair to OSR for TAAAs for inclusion in the review. The main outcomes of interest were prevention of aneurysm rupture (participants without aneurysm rupture up to 5 years from intervention), aneurysm-related mortality (30 days and 12 months), all-cause mortality, spinal cord ischaemia (paraplegia, paraparesis), visceral arterial branch compromise causing mesenteric ischaemia or renal failure, and rate of reintervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all titles and abstracts identified from the searches to identify those that met the inclusion criteria. We planned to undertake data collection, risk of bias assessment, and analysis in accordance with Cochrane recommendations. We planned to assess the certainty of the evidence using GRADE.

MAIN RESULTS

No RCTs or CCTs met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of endovascular compared to OSR in patients with TAAAs and are unable to provide any evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs addressing this objective are necessary, however conducting such studies will be logistically and ethically challenging for this life-threatening disease.

An in vitro Assessment of the Haemodynamic Features Occurring Within the True and False Lumens Separated by a Dissection Flap for a Patient-Specific Type B Aortic Dissection

One of the highest mortality rates of cardiovascular diseases is aortic dissections with challenging treatment options. Currently, less study has been conducted in developing in vitro patient-specific Type B aortic dissection models, which mimic physiological flow conditions along the true and false lumens separated by a dissection flap with multiple entry and exit tears. A patient-specific Stanford Type B aortic dissection scan was replicated by an in-house manufactured automatic injection moulding system and a novel modelling technique for creating the ascending aorta, aortic arch, and descending aorta incorporating arterial branching, the true/false lumens, and dissection flap with entry and exit intimal tears. The physiological flowrates and pressure values were monitored, which identified jet stream fluid flows entering and exiting the dissection tears. Pressure in the aorta’s true lumen region was controlled at 125/85 mmHg for systolic and diastolic values. Pressure values were obtained in eight sections along the false lumen using a pressure transducer. The true lumen systolic pressure varied from 122 to 128 mmHg along the length. Flow patterns were monitored by ultrasound along 12 sections. Detailed images obtained from the ultrasound transducer probe showed varied flow patterns with one or multiple jet steam vortices along the aorta model. The dissection flap movement was assessed at four sections of the patient-specific aorta model. The displacement values of the flap varied from 0.5 to 3 mm along the model. This model provides a unique insight into aortic dissection flow patterns and pressure distributions. This dissection phantom model can be used to assess various treatment options based on the surgical, endovascular, or hybrid techniques.

Differences in Mid-Term Outcomes Between Patients Undergoing Thoracic Endovascular Aortic Repair for Aneurysm or Acute Aortic Syndromes: Report From the Global Registry for Endovascular Aortic Treatment

PURPOSE

To analyze differences in baseline characteristics, overall mortality, device-related mortality, and re-intervention rates in patients who underwent thoracic endovascular aortic repair (TEVAR) for descending thoracic aortic aneurysm (DTAA) with atherosclerotic/degenerative cause or acute aortic syndrome (AAS), using the Global Registry For Endovascular Aortic Treatment (GREAT).

MATERIALS AND METHODS

Patients submitted to TEVAR for AAS or DTAA, included in GREAT, were eligible for this analysis. Primary outcome was 30-day all-cause mortality rate. Secondary outcomes were 30-day aorta-related mortality and re-intervention rate, 1-year and 3-year all-cause mortality, aorta-related mortality and re-intervention rate.

RESULTS

Five-hundred and seventy-five patients were analyzed (305 DTAA and 270 AAS). Thirty-day mortality rate was 1.3% and 1.8% for DTAA and AAS, respectively (p=0.741). One-year and 3-year mortality rates were 6.2% versus 9.3 and 17.3% versus 15.9% for DTAA and AAS, respectively (p=0.209 and p=0.655, respectively). Aorta-related mortality rates at 30 days, 1 year and 3 years were 1.3%, 1.3%, and 2.6% for DTAA, 1.8%, 4.2%, and 4.2% for AAS (p=ns). Re-intervention rates at 30 days, 1 year, and 3 years were 1.3%, 4.3%, and 7.5% for DTAA, 3.3%, 8.1%, and 10.7% for AAS (p=ns). Furthermore, a specific analysis with similar outcomes was performed dividing follow-up in 3 periods (1-30 days, 31-365 days, 366-1096 days) and describing mutual differences between 2 groups and temporal trends in each group.

CONCLUSION

Patients who underwent TEVAR for DTAA or AAS experienced different mortality and re-intervention rates among years during mid-term follow-up. Although all-cause related deaths within 30 days were TEVAR-related, aorta-related deaths were more common for AAS patients within 1 year. A greater re-intervention rate was described for AAS patients, although only 1 year after TEVAR.

Patient-specific computational modeling of endovascular aneurysm repair: State of the art and future directions

Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in-hospital mortality rates are smaller for EVAR than open repair (1%-2% vs. 3%-5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent-graft (SG) model choice, sizing, procedural options, and their implications on long-term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real-time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR-associated complications.

Combined thoracic endovascular aortic repair and endovascular aneurysm repair and the long-term consequences of altered cardiovascular haemodynamics on morbidity and mortality: case series and literature review

Background

Thoracic and abdominal aortic stent grafts are firmer and more rigid than the native aorta. Aortic implanted devices have been implicated in the development of acute systolic hypertension, elevated pulse pressure, and reduced coronary perfusion.

Case summary

We report four cases of staged thoracic endovascular aortic repair (TEVAR) and then endovascular aneurysm repair (EVAR). All patients had TEVAR first for thoracic aortic aneurysm and later on developed infra-renal abdominal aortic aneurysm (AAA) that required EVAR. There were three males and one female with a median age of 74.5 years (range 67.5-78.5). None of the patients developed aortic-related major clinical adverse effects or required any aortic intervention during their follow-up. However, within 2 years, all patients developed symptomatic left ventricular hypertrophy with diastolic dysfunction. All patients had bilateral lower limb oedema, with on and off chest pain and shortness of breath (SOB), necessitating coronary angiograms, which showed no evidence of coronary artery disease. Three patients died from cardiovascular-related morbidities, and the fourth patient is still complaining of SOB despite a normal coronary angiogram.

Discussion

Aortic-endograft compliance mismatch is an invisible enemy, with troubling consequences for the aorta proximal and distal to the endograft. Aortic stiffness due to vascular endograft could lead to cardiovascular adverse events, even in the absence of direct aortic-related complications. After combined TEVAR and EVAR, the compliance mismatch and elasticity loss are even more pronounced than with TEVAR alone, which necessitates patient monitoring for the development of cardiovascular complications.

Fluid-structure interaction: Insights into biomechanical implications of endograft after thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has developed to be the most effective treatment for aortic diseases. This study aims to evaluate the biomechanical implications of the implanted endograft after TEVAR. We present a novel image-based, patient-specific, fluid-structure computational framework. The geometries of blood, endograft, and aortic wall were reconstructed based on clinical images. Patient-specific measurement data was collected to determine the parameters of the three-element Windkessel. We designed three postoperative scenarios with rigid wall assumption, blood-wall interaction, blood-endograft-wall interplay, respectively, where a two-way fluid-structure interaction (FSI) method was applied to predict the deformation of the composite stent-wall. Computational results were validated with Doppler ultrasound data. Results show that the rigid wall assumption fails to predict the waveforms of blood outflow and energy loss (EL). The complete storage and release process of blood flow energy, which consists of four phases is captured by the FSI method. The endograft implantation would weaken the buffer function of the aorta and reduce mean EL by 19.1%. The closed curve area of wall pressure and aortic volume could indicate the EL caused by the interaction between blood flow and wall deformation, which accounts for 68.8% of the total EL. Both the FSI and endograft have a slight effect on wall shear stress-related-indices. The deformability of the composite stent-wall region is remarkably limited by the endograft. Our results highlight the importance of considering the interaction between blood flow, the implanted endograft, and the aortic wall to acquire physiologically accurate hemodynamics in post-TEVAR computational studies and the deformation of the aortic wall is responsible for the major EL of the blood flow.

Interventional Planning for Endovascular Revision of a Lateral Tunnel Fontan: A Patient-Specific Computational Analysis

Introduction

A 2-year-old female with hypoplastic left heart syndrome (HLHS)-variant, a complex congenital heart defect (CHD) characterized by the underdevelopment of the left ventricle, presented with complications following single ventricle palliation. Diagnostic work-up revealed elevated Fontan pathway pressures, as well as significant dilation of the inferior Fontan pathway with inefficient swirling flow and hepatic venous reflux. Due to the frail condition of the patient, the clinical team considered an endovascular revision of the Fontan pathway. In this work, we performed a computational fluid dynamics (CFD) analysis informed by data on anatomy, flow, and pressure to investigate the hemodynamic effect of the endovascular Fontan revision.

Methods

A patient-specific anatomical model of the Fontan pathway was constructed from magnetic resonance imaging (MRI) data using the cardiovascular modeling software CardiovasculaR Integrated Modeling and SimulatiON (CRIMSON). We first created and calibrated a pre-intervention 3D-0D multi-scale model of the patient’s circulation using fluid-structure interaction (FSI) analyses and custom lumped parameter models (LPMs), including the Fontan pathway, the single ventricle, arterial and venous systemic, and pulmonary circulations. Model parameters were iteratively tuned until simulation results matched clinical data on flow and pressure. Following calibration of the pre-intervention model, a custom bifurcated endograft was introduced into the anatomical model to virtually assess post-intervention hemodynamics.

Results

The pre-intervention model successfully reproduced the clinical hemodynamic data on regional flow splits, pressures, and hepatic venous reflux. The proposed endovascular repair model revealed increases of mean and pulse pressure at the inferior vena cava (IVC) of 6 and 29%, respectively. Inflows at the superior vena cava (SVC) and IVC were each reduced by 5%, whereas outflows at the left pulmonary artery (LPA) and right pulmonary artery (RPA) increased by 4%. Hepatic venous reflux increased by 6%.

Conclusion

Our computational analysis indicated that the proposed endovascular revision would lead to unfavorable hemodynamic conditions. For these reasons, the clinical team decided to forgo the proposed endovascular repair and to reassess the management of this patient. This study confirms the relevance of CFD modeling as a beneficial tool in surgical planning for single ventricle CHD patients.

Patient-specific computational fluid dynamics analysis of transcatheter aortic root replacement with chimney coronary grafts

OBJECTIVES

Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts.

METHODS

Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches. Computed assisted design tools were used to modify the geometry to create the post-procedural TARR configuration featuring the main aortic endograft integrated with 2 chimney grafts for coronary circulation. Computational Fluid Dynamics simulations were run in both pre- and post-procedural configurations using a pulsatile inflow and lumped parameter models at the outflows to simulate peripheral aortic and coronary circulation. Differences in coronary flow and pressure along the cardiac cycle were evaluated.

RESULTS

After the virtual implant of the TARR device with coronary grafts, the flow became more organized and less recirculation was seen in the ascending aorta. Coronary perfusion was guaranteed with negligible flow differences between pre- and post-procedural configurations. However, despite being well perfused by chimney grafts, the procedure induces an increase of the pressure drop between the coronary ostia and the ascending aorta of 8 mmHg.

CONCLUSIONS

The proposed numerical simulations, in the specific case under investigation, suggest that the TARR technique maintains coronary perfusion through the chimney grafts. This study calls for experimental validation and further analyses of the impact of TARR on cardiac afterload, decrease of aortic compliance and local pressure drop induced by the coronary chimney grafts.

Endovascular repair of ascending aortic diseases with custom-made endografts

OBJECTIVES

The aim of this article is to report the mid-term results of ascending thoracic endovascular aortic repair using a custom-made device (CMD).

METHODS

This was a retrospective study performed at tertiary centres. Nine patients considered unfit for open surgery received elective total endovascular repair of the ascending aorta with a Relay® (Terumo Aortic, Sunrise; FL, USA) CMD: pseudoaneurysn (n = 5), localized dissection (n =3) and contained rupture (n = 1).

RESULTS

Primary clinical success was achieved in all patients with no major complications and no early conversion to open surgery. All patients were discharged home and independent: median length of stay was 7 days (interquartile range, 6-18). No patient was lost to follow-up at a median 26 months (interquartile range, 12-36). Three patients died 2, 6 and 24 months after intervention; 1 was aorta related (late aorto-atrial fistula due to infection that required open surgery). At the last follow-up available, no endoleaks, migrations, fractures or ruptures were observed in the remaining 6 patients.

CONCLUSIONS

Ascending thoracic endovascular aortic repair with Terumo Aortic CMDs was technically feasible, effective and safe in very selected lesions. CMDs showed good ascending aorta conformability with different configurations and diameters, and satisfactory mid-term durability as shown by both structural integrity and aortic lesion exclusion.

Stent Graft Oversizing is Associated with an Increased Risk of Long-Term Left Ventricular Wall Thickening in Young Patients Following Thoracic Endovascular Aortic Repair

BACKGROUND

Left ventricular (LV) wall thickening occurs in patients following thoracic endovascular aortic repair (TEVAR). Clinical consequences of cardiovascular (CV) remodeling may be more significant younger patients with longer anticipated life spans. Risk factors for CV remodeling following TEVAR are unknown but may be related to graft size.

METHODS

A retrospective analysis was performed of a multicenter healthcare system including patients aged ≤60 who underwent TEVAR between 2011 and 2019 with at least 1 year follow-up computed tomography angiography imaging available. Standard perioperative variables, native aortic diameter, and stent graft specifications were collected. Graft oversizing was calculated by dividing proximal graft diameter by proximal aortic diameter on preoperative imaging. Posterior LV wall thickness was measured at baseline and interval increases were normalized to time-to-follow-up. Primary outcome was annual rate of posterior LV wall thickening.

RESULTS

One hundred one patients met inclusion criteria with a mean (SD) follow-up time of 1270 (693) days. Overall mean (SD) rate of LV wall thickness change was 0.534 (0.750) mm per year. Mean (SD) absolute LV wall thickness at most recent follow-up was 10.97 (2.85) mm for men, 9.69 (2.03) mm for women. Multivariate analysis demonstrated that higher rates of LV wall thickening were associated with narrower graft diameters (P = 0.0311). Greater absolute LV wall thickness at follow-up was associated with narrower grafts (P= 0.0155) and greater graft oversizing (P= 0.0376). Logistic regression demonstrated individuals who met criteria for LV hypertrophy were more likely to have narrower stent-grafts (P= 0.00798) and greater graft oversizing (P= 0.0315).

CONCLUSIONS

LV wall thickening occurred to a greater degree in individuals with narrower stent-grafts and higher rates of graft oversizing. This has significant implications for long-term cardiovascular health in younger patients may undergo TEVAR for atypical indications. Particular attention should be paid to long-term effects of stent-graft oversizing when selecting grafts in such populations.

Reflected wave intensity increases based on aortic diameter after endovascular aortic therapy in a goat model

Reflected wave increases after endovascular aortic repair (EVAR) in patients with aortic aneurysm. This affects the left ventricular (LV) diastolic function and leads to a poor prognosis. This study aimed to evaluate the relationship between increased reflected wave amplitude and aortic diameter after EVAR. EVAR was performed in seven healthy goats. We assessed wave intensity (WI), aortic diameter, and stiffness parameter β. Moreover, we evaluated the relationship between negative reflected wave (NW, reflected waves toward the heart from the periphery by WI) and other parameters after EVAR. Results showed an increase in stiffness parameter β (3.5 ± 0.3 vs 15.9 ± 4.7, p = 0.018) and a decrease in the change of aortic diameter (6.9 ± 0.7 vs 2.7 ± 0.4%, p = 0.018) after EVAR. The NW was significantly amplified after EVAR from baseline (−589.8 ± 143.4 to  − 1192.3 ± 303.7 mmHg-m/sec³, p = 0.043). The NW showed a significant correlation with maximum aortic diameter (R = 0.707, p = 0.038) and minimum aortic diameter (R = 0.724, p = 0.033). The reflected wave was enhanced after EVAR and was correlated to the aortic diameter at the stent-graft site. It is important to consider that patients with smaller aortic diameters in landing zone who undergo EVAR may develop LV dysfunction.

Comparison of Clinical Outcomes Following One versus Two Stage Hybrid Repair of Thoraco-Abdominal Aortic Aneurysms: A Comprehensive Meta-Analysis

OBJECTIVE

For thoraco-abdominal aortic aneurysms (TAAA), it is unclear whether it is better to perform hybrid repair in one (single) or two stages (staged). This study aimed to compare the clinical outcomes of single vs. staged hybrid repair of TAAA.

METHODS

The Medline, Embase, and Cochrane Databases (1 January 1994 to 11 May 2020) were searched for studies on hybrid repair of TAAA. Cohort studies and case series reporting outcomes of single and staged hybrid repair of TAAA were eligible for inclusion. The Newcastle-Ottawa scale and an 18 item tool were used to assess the risk of bias. The primary outcome was 30 day mortality, and the secondary outcomes included post-operative complications, overall survival, and other mid term events. A random effects model was used to calculate pooled estimates.

RESULTS

A total of 37 studies was included in the meta-analysis. The quality assessment of the included studies suggested low or moderate risk of bias. The pooled estimates for aneurysm rupture and death during stage interval were 2% (95% CI 0%-4%, I² = 0%) and 4% (95% CI 2%-7%, I² = 0%), respectively. Single repair was associated with a significantly higher 30 day risk of death when compared with patients who completed staged procedures successfully (OR 2.64, 95% CI 1.36-5.12, I² = 0%). Staged repair also had lower incidence of major adverse cardiac events (MACE) (single: 10%, 95% CI 5%-16%; staged: 2%, 95% CI 0%-5%) and intestinal complications (single: 15%, 95% CI 8%-25%; staged: 3%, 95% CI 1%-6%). For mid term outcomes, single and staged repair had comparable 12 month overall survival, aneurysm related mortality, rate of re-intervention, and graft patency.

CONCLUSION

Two stage hybrid repair may represent a better choice for patients with controlled risk of aneurysm rupture, because it can provide lower 30 day mortality risks, MACE, and intestinal complications, as well as comparable mid term outcomes. Randomised controlled trials are needed to ascertain the effect of repair staging in patients for elective TAAA.

Cardiac Stress in High-Risk Patients Undergoing Major Endovascular Surgery-Focus on Diastolic Function

OBJECTIVES

The purpose of this study was to determine the relationship between the changes in diastolic function and their association with cardiac biomarkers in the perioperative period in patients undergoing complex endovascular aortic repair.

DESIGN

Prospective observational study.

SETTING

Single-center academic hospital, central teaching hospital in Warsaw, Poland.

PARTICIPANTS

The study comprised 27 high-risk patients scheduled for elective endovascular repair of aortic aneurysm.

INTERVENTIONS

Complex endovascular procedure using branched endograft of the thoracoabdominal aorta. Branches of the stent grafts included renal arteries, the superior mesenteric artery, and the celiac trunk.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was to evaluate changes in diastolic function parameters assessed with transthoracic echocardiography at two and 24 hours postoperatively. The major secondary outcomes were changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin I concentrations, systolic function parameters, hemodynamic parameters at two and 24 hours, length of hospital stay, and 30-day mortality. There was a reduction in e' wave velocity on both the septal and lateral sides at two hours compared with the baseline (p = 0.041 and p = 0.05, respectively). There was an increase in both NT-proBNP and troponin I concentrations after surgery (p = 0.002 and p = 0.034, respectively), with troponin I peaking two hours after surgery and NT-proBNP peaking 24 hours after surgery.

CONCLUSIONS

Patients undergoing a branched endovascular aortic repair of a thoracoabdominal aortic aneurysm experience a cardiac insult that manifests with deterioration in diastolic parameters and concomitant increases of troponin and NT-proBNP concentrations. Additional large-scale prospective studies are required to confirm this phenomenon.

Ascending aortic rupture after zone 2 endovascular repair: a multiparametric computational analysis

A 74-year-old woman expired from ascending aortic rupture 3 months following branched zone 2 endovascular aortic repair. Multiparametric image-based computational evaluation of this case suggested that the stiffness mismatch between the endograft and the native aorta increased haemodynamic loads and likely led to the rupture of the ascending aorta. This under-recognized phenomenon should be considered in preoperative planning and presents suggestions for endograft development.

Influence of TEVAR on blood pressure in subacute type B aortic dissection (TBAD) patients with refractory and non-refractory arterial hypertension

BACKGROUND

Aim of this study was to compare the modifications of systemic blood pressure in patients with subacute type b aortic dissection (TBAD) and refractory (rHTN) and non-refractory arterial hypertension (N-rHTN) treated by thoracic endovascular aortic repair (TEVAR).

METHODS

Patients were divided into two groups, rHTN defined as blood pressure >140/90 mmHg with ≥5 antihypertensive drugs and patients with N-rHTN. Primary endpoint was the variation of mean systolic, diastolic and overall pressure (MSP, MDP and MAP) before and after antihypertensive treatment or TEVAR. Secondary endpoints were the 30-days mortality. Fifty-seven patients were included in this study.

RESULTS

Of the 44 Patients of the TEVAR group 21 were included in the N-rHTN group. The MSP before and after surgery for the N-rHTN group was 130 (±10 SD) and 111 (±22 SD) mmHg, P=0.01. In the rHTN group 164 (±17 SD) and 118 (±17 SD) mmHg (P=0.01). The reduction of MSP was greater in the rHTN group (P=0.01). The MAP before and after the TEVAR for the N-rHTN group was 90 (±10 SD) and 74 (±12 SD) mmHg (P=0.01), in the rHTN group 111 (±14 SD) and 70 (±9 SD) mmHg (P=0.01). The overall mortality rate group was 2.2% (1/44).

CONCLUSIONS

TEVAR for TBAD appears to positively affect blood pressure in patients with rHTN and N-rHTN.

Aortic stiffness and related complications after endovascular repair of blunt thoracic aortic injury in young patients

Summary: Background: This study aimed to evaluate the changes in aortic stiffness in young patients undergoing thoracic endovascular aortic repair (TEVAR) after blunt thoracic aortic injury (TBAI) and to examine the associated cardiovascular complications during follow-up. Patients and methods: We included survivors of TBAI who underwent stent graft placement between November 2009 and November 2019 and gave their consent to participate. Patients with relevant cardiovascular risk factors, comorbidities with potential impact on arterial stiffness, and prior aortic surgical or endovascular interventions were excluded. Fourteen TEVAR patients prospectively underwent clinical and noninvasive examinations and morphological imaging (mean time of follow-up and duration of implanted stent graft: 5.3 ± 1.8 years; mean age: 35.1 ± 8.7 years) and were compared to 14 healthy controls (matched for sex, age, height, and body mass index) in order to evaluate aortic stiffness. During the follow-up examinations, we assessed the pulse wave velocity (PWV; m/s) and development of arterial hypertension or heart failure, as indicated by N-terminal pro-brain natriuretic peptide (NT-proBNP; pg/mL) levels and performed echocardiography. Results: A significant increase in PWV values was recorded in the TEVAR group (median = 10.1; interquartile range [IQR] = 8.9–11.6) compared to the healthy controls (median = 7.3; IQR = 6.7–8.4), with an increase in the rank mean PWV (+ 3.8; Mann-Whitney U test p < .001). NT-proBNP levels of patients after TEVAR did not vary significantly compared to those of healthy controls (Mann-Whitney U test, p = .154). After TEVAR, five patients developed arterial hypertension during the follow-up, and three of them exhibited diastolic dysfunction. Conclusions: In young patients, TEVAR after TBAI may cause adverse cardiovascular complications due to increased aortic stiffness; therefore, screening for arterial hypertension during follow-up is recommended.

Computational analysis of renal artery flow characteristics by modeling aortoplasty and aortic bypass interventions for abdominal aortic coarctation

OBJECTIVE

Suprarenal abdominal aortic coarctation (SAAC) alters flow and pressure patterns to the kidneys and is often associated with severe angiotensin-mediated hypertension refractory to drug therapy. SAAC is most often treated by a thoracoabdominal bypass (TAB) or patch aortoplasty (PA). It is currently unclear what effect these interventions have on renal flow and pressure waveforms. This study, using retrospective data from a patient with SAAC subjected to a TAB, undertook computational modeling to analyze aortorenal blood flow preoperatively as well as postoperatively after a variety of TAB and PA interventions.

METHODS

Patient-specific anatomic models were constructed from preoperative computed tomography angiograms of a 9-year-old child with an isolated SAAC. Fluid-structure interaction (FSI) simulations of hemodynamics were performed to analyze preoperative renal flow and pressure waveforms. A parametric study was then performed to examine the hemodynamic impact of different bypass diameters and patch oversizing.

RESULTS

Preoperative FSI results documented diastole-dominated renal perfusion with considerable high-frequency disturbances in blood flow and pressure. The postoperative TAB right and left kidney volumes increased by 58% and 79%, respectively, reflecting the increased renal artery blood flows calculated by the FSI analysis. Postoperative increases in systolic flow accompanied decreases in high-frequency disturbances, aortic pressure, and collateral flow after all surgical interventions. In general, lesser degrees of high-frequency disturbances followed PA interventions. High-frequency disturbances were eliminated with the 0% PA in contrast to the 30% and 50% PA oversizing and TAB interventions, in which these flow disturbances remained.

CONCLUSIONS

Both TAB and PA dramatically improved renal artery flow and pressure waveforms, although disturbed renal waveforms remained in many of the surgical scenarios. Importantly, only the 0% PA oversizing scenario eliminated all high-frequency disturbances, resulting in nearly normal aortorenal blood flow. The study also establishes the relevance of patient-specific computational modeling in planning interventions for the midaortic syndrome.

Endovascular Repair of Blunt Thoracic Aortic Trauma is Associated With Increased Left Ventricular Mass, Hypertension, and Off-target Aortic Remodeling

BACKGROUND

Aortic elasticity creates a cushion that protects the heart from pressure injury, and a recoil that helps perfuse the coronary arteries. TEVAR has become first-line therapy for many aortic pathologies including trauma, but stent-grafts stiffen the aorta and likely increase LV afterload.

OBJECTIVE

Test the hypothesis that trauma TEVAR is associated with LV mass increase and adverse off-target aortic remodeling.

METHODS

Computed Tomography Angiography (CTA) scans of 20 trauma TEVAR patients (17 M/3 F) at baseline [age 34.9 ± 18.5 (11.4-71.5) years] and 5.1 ± 3.1 (1.1-12.3) years after repair were used to measure changes in LV mass, LV mass index, and diameters and lengths of the ascending thoracic aorta (ATA). Measurements were compared with similarly-aged control patients without aortic repair (21 M/21 F) evaluated at similar follow-ups.

RESULTS

LV mass and LV mass index of TEVAR patients increased from 138.5 ± 39.6 g and 72.35 ± 15.17 g/m to 173.5 ± 50.1 g and 85.48 ± 18.34 g/m at the rate of 10.03 ± 12.79 g/yr and 6.25 ± 10.28 g/m/yr, whereas in control patients LV characteristics did not change. ATA diameters of TEVAR patients increased at a rate of 0.60 ± 0.80 mm/yr, which was 2.4-fold faster than in controls. ATA length in both TEVAR and control patients increased at 0.58 mm/yr. Half of TEVAR patients had hypertension at follow-up compared to only 5% at baseline.

CONCLUSIONS

TEVAR is associated with LV mass increase, development of hypertension, and accelerated expansile remodeling of the ascending aorta. Although younger trauma patients may adapt to these effects, these changes may be even more important in older patients with other aortic pathologies and diminished baseline cardiac function.

Decreased biventricular function following thoracic endovascular aortic repair

OBJECTIVES

Preclinical studies have suggested acute stiffening of the aorta following experimental thoracic endovascular aortic repair (TEVAR), resulting in acute elevated pulse pressure, hypertension and possibly heart failure. The aim of this study was to evaluate cardiac remodelling following TEVAR.

METHODS

From 2005 to 2018, 519 TEVAR procedures were performed at a single centre. Transthoracic echocardiography was performed pre- and post-TEVAR in 31 patients without previous replacement of the thoracic aorta. Patient characteristics, drug information, radiographic and follow-up data were evaluated. Aortic details were measured in multiplanar reconstruction.

RESULTS

Transthoracic echocardiography was performed 2 ± 2 years after TEVAR. At this time, patients received significantly more antihypertensive drugs compared to the pre-TEVAR intake (beta-blocker therapy: P = 0.037; calcium channel blocker: P = 0.022). Compared to pre-TEVAR, there was a significant reduction in the left ventricular ejection fraction (P = 0.008) and tricuspid annular plane systolic excursion (P = 0.013) post-TEVAR. A significant increase in the left ventricular mass was not detected in this study (P = 0.95). The mean distance of 163 ± 66 mm of the descending aorta was covered.

CONCLUSIONS

This study suggests negative cardiac remodelling with a decrease in the left and right ventricular function following TEVAR despite an increase in oral antihypertensive medication. The impact of stiffer endovascular grafts compared with the native aortic wall should be considered by endovascular specialists and manufacturers.