Evaluation of Different Cannulation Strategies for Aortic Arch Surgery Using a Cardiovascular Numerical Simulator.

Aortic disease has a significant impact on quality of life. The involvement of the aortic arch requires the preservation of blood supply to the brain during surgery. Deep hypothermic circulatory arrest is an established technique for this purpose, although neurological injury remains high. Additional techniques have been used to reduce risk, although controversy still remains. A three-way cannulation approach, including both carotid arteries and the femoral artery or the ascending aorta, has been used successfully for aortic arch replacement and redo procedures. We developed circuits of the circulation to simulate blood flow during this type of cannulation set up. The CARDIOSIM© cardiovascular simulation platform was used to analyse the effect on haemodynamic and energetic parameters and the benefit derived in terms of organ perfusion pressure and flow. Our simulation approach based on lumped-parameter modelling, pressure-volume analysis and modified time-varying elastance provides a theoretical background to a three-way cannulation strategy for aortic arch surgery with correlation to the observed clinical practice.

Alternative Approach for Cerebral Protection during Complex Aortic Arch and Redo Surgery.

Total arch replacement remains a very demanding surgical procedure. It can be associated with reasonable long-term outcomes but carries serious perioperative complications. Aortic arch surgery has progressed in recent years to a wider adoption of reproducible and reliable techniques. Conventional open, surgical aortic arch replacement is currently offered to the majority of patients, although hybrid and wholly endovascular techniques are gaining popularity. With regards to open arch replacement, the nuances of surgical technique, the mode of cannulation and the optimal cerebral protection protocols remain a matter of debate. We propose an alternative cannulation approach facilitated by the cooperation between cardiac and vascular surgeons. A three-way arterial cannulation including both carotid arteries and the femoral artery (or ascending aorta) is the key feature of this approach. A case series of complex patients is presented to show both the feasibility and relative safety of a standardised new approach with a 100% technical success rate and a 16% 30-day mortality. The three-way cannulation approach may have a role to play for complex and extensive procedures requiring prolonged cerebral protection. We believe that a shared skill set from cardiac and vascular specialists is essential for the safe management and successful outcomes using this adaptive technique.

Cardiac and Vascular Surgeons for the Treatment of Aortic Disease: A Successful Partnership for Decision-Making and Management of Complex Cases.

Traditionally, cardiac and vascular surgeons have been treating diseases of the aorta as individual specialists. Neither cardiac nor vascular surgeons have ever considered the aorta as a whole, which can be diseased throughout its length at the same time requiring a more thoughtful and different approach. Aortic dissection and aneurysmal disease may well benefit from a multidisciplinary approach. In the context of this review, we discuss examples of joint operating between cardiac and vascular surgeons that may well become a more routine approach in more units in the future.

Delayed repair of aortic dissection in sickle cell anaemia as a combined cardiac and vascular surgical approach.

We discuss a patient who presented with a type B aortic dissection with a retrograde progression in the context of sickle cell anaemia. Given the involvement of the superior mesenteric artery and concern for bowel ischaemia, a delayed approach was considered. Subsequently, a frozen elephant trunk was performed in the hybrid theatre with the back-up of the vascular surgeon for mesenteric protection. A technically demanding procedure followed by a prolonged and challenging postoperative course finally led to a successful outcome. We argue that the case presented is an example of how a close cooperation between professionals can offer additional options to treatment based on a mixture of skills and background to achieve the desired outcome.

Video motion analysis in live coronary angiography differentiates levels of experience and provides a novel method of skill assessment.

AIMS: Video motion analysis (VMA) uses fluoroscopic sequences to derive catheter and guidewire movement, and is able to calculate 2D catheter-tip path length (PL) on the basis of frame-by-frame pixel coordinates. The objective of this study was to validate VMA in coronary angiography as a method of skill assessment. METHODS AND RESULTS: Forty-seven coronary interventions performed by 10 low- (<1,000 cases; group A), five medium- (1,000-4,000; group B) and six high- (>4,000; group C) experience-volume cardiologists were prospectively recorded and analysed using VMA software. Total PL was calculated and procedure, fluoroscopy times, and radiation dose were recorded. Comparisons of PL were made between groups of experience. Groups A, B and C performed 24, 14 and 6 paired (right and left coronary) cannulations, respectively. Calculation of PL was possible in all recorded cases and significantly correlated with procedure (p=<0.001, rho=0.827) and fluoroscopy times (p=<0.001, rho=0.888). Median total path length (combined right and left coronaries) was significantly shorter in group C which used 3,836 pixels of movement (IQR: 3,003-4,484) vs. 10,556 (7,242-31,408) in group A (p=<0.001) and 8,725 (5,187-15,150) in group B (p=0.013). CONCLUSIONS: VMA in coronary angiography is feasible and PL is able to differentiate levels of experience.

Objective Assessment of Endovascular Navigation Skills with Force Sensing.

Despite the increasing popularity of endovascular intervention in clinical practice, there remains a lack of objective and quantitative metrics for skill evaluation of endovascular techniques. Data relating to the forces exerted during endovascular procedures and the behavioral patterns of endovascular clinicians is currently limited. This research proposes two platforms for measuring tool forces applied by operators and contact forces resulting from catheter-tissue interactions, as a means of providing accurate, objective metrics of operator skill within a realistic simulation environment. Operator manipulation patterns are compared across different experience levels performing various complex catheterization tasks, and different performance metrics relating to tool forces, catheter motion dynamics, and forces exerted on the vasculature are extracted. The results depict significant differences between the two experience groups in their force and motion patterns across different phases of the procedures, with support vector machine (SVM) classification showing cross-validation accuracies as high as 90% between the two skill levels. This is the first robust study, validated across a large pool of endovascular specialists, to present objective measures of endovascular skill based on exerted forces. The study also provides significant insights into the design of optimized metrics for improved training and performance assessment of catheterization tasks.

Targeted next-generation sequencing makes new molecular diagnoses and expands genotype-phenotype relationship in Ehlers-Danlos syndrome.

PURPOSE: Ehlers-Danlos syndrome (EDS) comprises a group of overlapping hereditary disorders of connective tissue with significant morbidity and mortality, including major vascular complications. We sought to identify the diagnostic utility of a next-generation sequencing (NGS) panel in a mixed EDS cohort. METHODS: We developed and applied PCR-based NGS assays for targeted, unbiased sequencing of 12 collagen and aortopathy genes to a cohort of 177 unrelated EDS patients. Variants were scored blind to previous genetic testing and then compared with results of previous Sanger sequencing. RESULTS: Twenty-eight pathogenic variants in COL5A1/2, COL3A1, FBN1, and COL1A1 and four likely pathogenic variants in COL1A1, TGFBR1/2, and SMAD3 were identified by the NGS assays. These included all previously detected single-nucleotide and other short pathogenic variants in these genes, and seven newly detected pathogenic or likely pathogenic variants leading to clinically significant diagnostic revisions. Twenty-two variants of uncertain significance were identified, seven of which were in aortopathy genes and required clinical follow-up. CONCLUSION: Unbiased NGS-based sequencing made new molecular diagnoses outside the expected EDS genotype-phenotype relationship and identified previously undetected clinically actionable variants in aortopathy susceptibility genes. These data may be of value in guiding future clinical pathways for genetic diagnosis in EDS.Genet Med 18 11, 1119-1127.

Reducing contact forces in the arch and supra-aortic vessels using the Magellan robot.

OBJECTIVE: Conventional catheter manipulation in the arch and supra-aortic trunks carries a risk of cerebral embolization. This study proposes a platform for detailed quantitative analysis of contact forces (CF) exerted on the vasculature, in order to investigate the potential advantages of robotic navigation. METHODS: An anthropomorphic phantom representing a type I bovine arch was mounted and coupled onto a force/torque sensor. Three-axis force readings provided an average root-mean-square modulus, indicating the total forces exerted on the phantom. Each of the left subclavian, left common carotid, and right common carotid arteries was cannulated within a simulated endovascular suite with conventional (n = 42) vs robotic techniques (n = 30) by two operator groups: experts and novices. The procedure path was divided into three phases, and performance metrics corresponding to mean and maximum forces, force impact over time, standard deviation of forces, and number of significant catheter contacts with the arterial wall were extracted. RESULTS: Overall, median CF were reduced from 1.20 N (interquartile range [IQR], 0.98-1.56 N) to 0.31 N (IQR, 0.26-0.40 N; P < .001) for the right common carotid artery; 1.59 N (IQR, 1.11-1.85 N) to 0.33 N (IQR, 0.29-0.43 N; P < .001) for the left common carotid artery; and 0.84 N (IQR, 0.47-1.08 N) to 0.10 N (IQR, 0.07-0.17 N; P < .001) for the left subclavian artery. Robotic navigation resulted in significant reductions for the mean and maximum forces for each procedural phase. Significant improvements were also seen in other metrics, particularly at the target vessel ostium and for the more anatomically challenging procedural phases. Force reductions using robotic technology were evident for both novice and expert groups. CONCLUSIONS: Robotic navigation can potentially reduce CF and catheter-tissue contact points in an in vitro model, by enhancing catheter stability and control during endovascular manipulation.

Leiomyosarcoma of the thoracic aorta in a patient with hypertrophic cardiomyopathy.

We report a case of leiomyosarcoma of the thoracic aorta in a 49-year-old male patient with history of hypertrophic cardiomyopathy. The only presenting symptom was back pain localized under the left scapula with the frequency and severity of the pain increasing with time. Imaging studies detected the presence of an aortic tumor. The tumor was excised en bloc, and an interposition graft was implanted. The histology showed a fully excised grade 3 leiomyosarcoma. This article discusses features of this rare condition.

Virtual reality simulation for the optimization of endovascular procedures: current perspectives.

Endovascular technologies are rapidly evolving, often requiring coordination and cooperation between clinicians and technicians from diverse specialties. These multidisciplinary interactions lead to challenges that are reflected in the high rate of errors occurring during endovascular procedures. Endovascular virtual reality (VR) simulation has evolved from simple benchtop devices to full physic simulators with advanced haptics and dynamic imaging and physiological controls. The latest developments in this field include the use of fully immersive simulated hybrid angiosuites to train whole endovascular teams in crisis resource management and novel technologies that enable practitioners to build VR simulations based on patient-specific anatomy. As our understanding of the skills, both technical and nontechnical, required for optimal endovascular performance improves, the requisite tools for objective assessment of these skills are being developed and will further enable the use of VR simulation in the training and assessment of endovascular interventionalists and their entire teams. Simulation training that allows deliberate practice without danger to patients may be key to bridging the gap between new endovascular technology and improved patient outcomes.

Endovascular treatment of thoracic aortic aneurysms with a short proximal landing zone using scalloped endografts.

BACKGROUND: The suitability of the proximal landing zone remains one of the main limitations to thoracic endovascular aortic repair (TEVAR). The advent of custom-made scalloped stent grafts widens the endovascular options for patients with challenging anatomy. The objective of this study was to present our early and midterm results of custom-made scalloped thoracic stent grafts. METHODS: Prospectively acquired data relating to patient demographics, procedure details, clinical outcome, and complications were analyzed. In addition, we analyzed preoperative and postoperative computed tomography scans to evaluate aneurysm morphology, graft placement, side-vessel patency, and endoleaks. RESULTS: Twenty-one patients with a median age of 71 years (range, 35-81 years) underwent custom-made scalloped TEVAR, eight of whom had a concomitant hybrid repair. Procedural success was achieved in all cases. Proximal seal was achieved in all cases, with no type I endoleaks. There were no cases of retrograde dissection and no conversions to open repair. The median follow-up period was 36 weeks (range, 3-183 weeks). Two patients died in the hospital. Three patients suffered a stroke. Three patients had a type II endoleak, one of whom had significant sac enlargement requiring reintervention. One patient had a type III endoleak requiring reintervention. There were no cases of graft migration. CONCLUSIONS: Our midterm results show that custom-made scalloped TEVAR is an acceptable treatment of thoracic aortic aneurysms with a short proximal landing zone. Longer term outcome data are required to establish wider use of scalloped thoracic endografts.

New-generation stent grafts for endovascular management of thoracic pseudoaneurysms after aortic coarctation repair.

OBJECTIVE: Late thoracic aneurysms develop in 5% to 12% of patients having undergone open repair for coarctation of the aorta (CoA). We report our early results for thoracic endovascular aortic repair for pseudoaneurysms after CoA repair. METHODS: From 2008 to 2013, data regarding demographics, aneurysm morphology, procedure, and follow-up were collected prospectively on all patients treated for pseudoaneurysms after CoA repair. Retrospective analysis of identified patients was then performed. RESULTS: Thirteen patients (six men, seven women) were treated. Patients were a median age, 45 years (interquartile range (IQR), 39-56; range, 27-66 years, and the median time after CoA repair to aneurysm treatment was 34 years (IQR, 24-40 years). All patients had saccular pseudoaneurysms of the aortic arch, with a median aneurysm size of 4.1 cm (IQR, 3.4-5.1 cm). The left subclavian artery (LSCA) was involved in 10 patients and was occluded at presentation in three. Four patients had concurrent LSCA revascularization with carotid-subclavian bypass, one had aortic arch hybrid repair, and the LSCA was intentionally covered in two patients. Patients underwent thoracic endovascular aortic repair using the conformable TAG (6 of 13; W. L. Gore & Associates, Flagstaff, Ariz), Valiant device (4 of 13; Medtronic, Minneapolis, Minn), and a custom-made Relay endograft with LSCA scallop (4 of 13; Bolton Medical, Barcelona, Spain). Technical success was 100%, with satisfactory deployment of the stent grafts in all patients. There was no 30-day mortality, stroke, or paraplegia. Median follow-up was 15 months (IQR, 9-19 months; range, 1-67 months). Two type II endoleaks from an intercostal artery were managed conservatively, and one type Ib endoleak was treated successfully with distal stent extension. CONCLUSIONS: In this cohort, new-generation stent grafts have good early clinical and radiologic outcomes, avoiding the need for redo open surgery. Management of the LSCA can be tailored to individual patients with new stent graft technology. Long-term follow-up of these patients is crucial to understanding whether endovascular management of this cohort is acceptable.

Endovascular repair of ruptured abdominal aortic aneurysm: technical and team training in an immersive virtual reality environment.

PURPOSE: This study evaluates a fully immersive simulated angiosuite for training and assessment of technical endovascular and human factor skills during a crisis scenario. MATERIALS AND METHODS: Virtual reality (VIST-C, Mentice) simulators were integrated into a simulated angiosuite (ORCAMP, Orzone). Teams, lead by experienced (N = 5) or trainee (N = 5) endovascular specialists, performed simulated endovascular ruptured aortic aneurysm repair (rEVAR). Timed performance metrics were recorded as surrogate measures of performance. Participants (N = 22) completed postprocedure questionnaires evaluating face validity, as well as technical and human factor aspects, of the simulation on a Likert scale from 1 (not at all) to 5 (very much). RESULTS: Experienced team leaders were significantly faster than trainees in obtaining proximal control with an intra-aortic occlusion balloon (352 vs. 501 s, p = 0.047) and all completed the procedure within the allotted time, whilst no trainee was able to do so. Total fluoroscopy times were significantly lower in the experienced group (782 vs. 1,086 s, p = 0.016). Realism of the simulated angiosuite was scored highly by experienced team leaders (median 4/5, IQR 4-5). Participants found the simulation useful for acquiring technical (4/5, IQR 4-5) and communication skills (4/5, IQR 4-5) and particularly valuable for enhancing teamwork (5/5, IQR 4-5) and patient safety (5/5, IQR 4-5). CONCLUSION: This study shows feasibility of creation of a crisis scenario in a fully immersive angiosuite simulation and team performance of a simulated rEVAR. Performance metrics differentiated between experienced specialists and trainees, and the realism of the simulation exercise and environment were rated highly by experienced endovascular specialists. This simulation has potential as a powerful training and assessment tool with opportunities to improve team performance in rEVAR through both technical and human factor skills training.

The use of robotic endovascular catheters in the facilitation of transcatheter aortic valve implantation.

OBJECTIVES: The use of transcatheter aortic valve implantation (TAVI) is rapidly increasing with advances in technology and improved clinical outcomes. Adoption of robotic catheter technologies could have a role in TAVI, in different stages of the procedure, to improve endovascular tool manipulation and potentially reduce the risk of cerebral embolization. The aim was to determine whether there are advantages in using a robotic catheter for TAVI in the initial stages of the procedure; aortic arch navigation and valve crossing. METHODS: A silicone in vitro model of the aorta and stenotic aortic valve was developed. Fifteen operators performed the fluoroscopy-guided simulation using manual and robotic techniques. Performance metrics-time and vessel wall contact (wall-hits) were compared (Wilcoxon's signed-rank test). RESULTS: Overall, the time taken for robotic arch navigation was increased (3.09 min interquartile range (1.24-6.29) vs 1.21 min (0.15-4.42); P = 0.03). Contact with the aortic arch wall, however, significantly decreased using the robotic catheter: wall-hits 1 (0-5) vs 6 (2-22), P < 0.01. For valve crossing, there was no significant increase in time and wall-hits when using the robotic technology. CONCLUSIONS: Use of robotic catheter technology is feasible in the initial stages of TAVI. Although it takes longer, robotic navigation reduces contact with the aortic arch wall, potentially reducing the embolic risk during endovascular manipulation. Using a robotic catheter is possible without increasing the number of wall-hits during valve crossing. This may provide a stable platform for wire positioning in the ventricle. With improvements in technology, perhaps allowing valve deployment, the stability and accuracy of the robotic arm may further improve performance.

In vitro fenestration of aortic stent-grafts: implications of puncture methods for in situ fenestration durability.

PURPOSE: To investigate the quality of stent-graft fenestrations created in vitro using different needle puncture and balloon dilation angles in different commercial endografts. METHODS: Fenestrations were made in a standardized fashion in 3 different endograft types: Talent monofilament twill woven polyester, Zenith multifilament tubular woven polyester, and Endofit thin-walled expanded polytetrafluoroethylene (PTFE). Punctures were made at 30°, 60°, and 90° angles using a 20-G needle and dilated using 6-mm standard and 7-mm cutting balloons; at least 6 fenestrations were made at each angle with standard balloons and at least 6 with cutting balloons. The 137 fenestrations were examined under light microscopy; quantitative and qualitative digital image analysis was performed to determine size, shape, and fenestration quality. RESULTS: PTFE grafts were easier to puncture/dilate, resulting in larger, elliptical fenestrations with overall better quality than the Dacron grafts; however, the puncture/dilation angle made an impact on the shape and quality of fenestrations. A significant number of fabric tears were observed in PTFE fabric at <90° puncture/dilation angles compared to Dacron grafts. In Dacron grafts, fenestration quality was significantly higher with 90° puncture/dilation angles (higher in Talent grafts). Cutting balloon use resulted in significantly more fabric tears and poor quality fenestrations in all graft types. CONCLUSION: Different endografts behave significantly differently when fenestrations are fashioned. Optimum puncture/dilation is important when considering in vivo fenestration techniques. Improvements in instrumentation, materials, and techniques are required to make this a reliable and reproducible endovascular option.

Salmonella mycotic thoracoabdominal aortic aneurysm associated with chronic lymphocytic leukemia.

Non-typhoidal Salmonella infections typically cause self-limiting gastroenteritis. However, extraintestinal focal infections, including mycotic aneurysms of the aorta, can also occur. We present the case of a 71-year-old man with chronic lymphocytic leukemia (CLL) and a large type V thoracoabdominal mycotic aneurysm infected with Salmonella enteritidis, complicated by thoracolumbar spondylodiscitis, paravertebral collections, and epidural abscess. This is the first report of Salmonella aortitis in the setting of CLL, and the unusual extent of local infective invasion seen here with Salmonella enteritidis infection raises a suspicion of CLL-related immunosuppression as a direct predisposing factor. This case illustrates the need to consider the possibility of an immune defect, even in CLL patients with normal leukocyte counts. The underlying mechanisms are unclear, but are likely to involve defects in cell-mediated immunity, thought to be of particular importance in invasive infections with intracellular pathogens such as Salmonella spp.

Surgical technology and operating-room safety failures: a systematic review of quantitative studies.

BACKGROUND: Surgical technology has led to significant improvements in patient outcomes. However, failures in equipment and technology are implicated in surgical errors and adverse events. We aim to determine the proportion and characteristics of equipment-related error in the operating room (OR) to further improve quality of care. METHODS: A systematic review of the published literature yielded 19 362 search results relating to errors and adverse events occurring in the OR, from which 124 quantitative error studies were selected for full-text review and 28 were finally selected. RESULTS: Median total errors per procedure in independently-observed prospective studies were 15.5, interquartile range (IQR) 2.0-17.8. Failures of equipment/technology accounted for a median 23.5% (IQR 15.0%-34.1%) of total error. The median number of equipment problems per procedure was 0.9 (IQR 0.3-3.6). From eight studies, subdivision of equipment failures was possible into: equipment availability (37.3%), configuration and settings (43.4%) and direct malfunctioning (33.5%). Observed error rates varied widely with study design and with type of operation: those with a greater burden of technology/equipment tended to show higher equipment-related error rates. Checklists (or similar interventions) reduced equipment error by mean 48.6% (and 60.7% in three studies using specific equipment checklists). CONCLUSIONS: Equipment-related failures form a substantial proportion of all error occurring in the OR. Those procedures that rely more heavily on technology may bear a higher proportion of equipment-related error. There is clear benefit in the use of preoperative checklist-based systems. We propose the adoption of an equipment check, which may be incorporated into the current WHO checklist.

Robot-assisted fenestrated endovascular aneurysm repair (FEVAR) using the Magellan system.

A 67-year-old man underwent robot-assisted three-vessel fenestrated endovascular aneurysm repair (FEVAR) for a 7.3-cm juxtarenal aneurysm. The 6-F robotic catheter was manipulated from a remote workstation, away from the radiation source. Robotic cannulation of the left renal artery was achieved within 3 minutes. System setup time was 5 minutes. There were no postoperative complications. Computed tomography angiography performed at discharge and at 4-month follow-up confirmed target vessel patency with no evidence of an endoleak. Selective cannulation of target vessels during FEVAR using this novel technology is feasible. Endovascular robotics may have a role in simplifying complex endovascular tasks and potentially reducing radiation exposure to the operator.

Initial findings and potential applicability of computational simulation of the aorta in acute type B dissection.

OBJECTIVE: Type B aortic dissection can be acutely complicated by rapid expansion, rupture, and malperfusion syndromes. Short-term adverse outcomes are associated with failure of the false lumen to thrombose. The reasons behind false lumen patency are poorly understood, and the objective of this pilot study was to use computational fluid dynamics reconstructions of aortic dissection cases to analyze the effect of aortic and primary tear morphology on flow characteristics and clinical outcomes in patients with acute type B dissections. METHODS: Three-dimensional patient-specific aortic dissection geometry was reconstructed from computed tomography scans of four patients presenting with acute type B aortic dissection and a further patient with sequential follow-up scans. The cases were selected based on their clinical presentation. Two were complicated by acute malperfusion that required emergency intervention. Three patients were uncomplicated and were managed conservatively. The patient-specific aortic models were used in computational simulations to assess the effect of aortic tear morphology on various parameters including flow, velocity, shear stress, and turbulence. RESULTS: Pulsatile flow simulation results showed that flow rate into the false lumen was dependent on both the size and position of the primary tear. Linear regression analysis demonstrated a significant relationship between percentage flow entering the false lumen and the size of the primary entry tear and an inverse relationship between false lumen flow and the site of the entry tear. Subjects complicated by malperfusion had larger-dimension entry tears than the uncomplicated cases (93% and 82% compared with 32% and 55%, respectively). Blood flow, wall shear stress, and turbulence levels varied significantly between subjects depending on aortic geometry. Highest wall shear stress (>7 Pa) was located at the tear edge, and progression of false lumen thrombosis was associated with prolonged particle residence times. CONCLUSIONS: Results obtained from this preliminary work suggest that aortic morphology and primary entry tear size and position exert significant effects on flow and other hemodynamic parameters in the dissected aorta in this preliminary work. Blood flow into the false lumen increases with increasing tear size and proximal location. Morphologic analysis coupled with computational fluid dynamic modeling may be useful in predicting acute type B dissection behavior allowing for selection of proper treatment modalities, and further confirmatory studies are warranted.