Clinical competence statement on thoracic endovascular aortic repair (TEVAR)—multispecialty consensus recommendations

A scoping review to identify competencies for transcatheter cardiovascular procedures

OBJECTIVES

Transcatheter procedures are increasingly being recognized as a priority for cardiac surgeons and cardiac surgery trainees. The optimal method of teaching these procedures during residency training has not been established. We used an evidence-based approach to systematically review the literature and identify competencies to inform future paradigms of transcatheter training in cardiac surgery.

METHODS

A scoping review was conducted to retrieve relevant literature on the performance of transcatheter cardiovascular procedures, identify competencies required by surgical residents learning to perform these procedures, and develop a preliminary list of competencies for consideration during transcatheter training. MEDLINE, Scopus, and ERIC were queried until April 1, 2020, using a systematic search strategy. No limitations were placed on publication date or type.

RESULTS

A total of 1456 sources of evidence were retrieved. After deduplication and screening, there remained 33 that were included in the scoping review, published between 2006 and 2020. The distribution of publication types included 10 comparative studies (30.3% of total), 8 societal statements (24.2% of total), 5 surveys and 5 opinion articles (each 15.2% of total), 2 editorials and 2 descriptions of a simulator (each 6.1% of total), and 1 narrative review (3.0% of total). From these, a total of 400 items were identified and organized into 97 competencies.

CONCLUSIONS

Evidence on the competencies required to perform transcatheter cardiovascular procedures is available from a variety of sources. The identified competencies may be a useful resource for developing curricula and teaching transcatheter procedures to cardiac surgery residents.

Occurrence and outcomes of type 3 endoleaks in endovascular aortic repair within the Vascular Quality Initiative database

Objectives

Type 3 endoleaks (T3ELs) represent a lack of aneurysm protection from systemic pressure. Previous studies have found a ~2% incidence of T3EL after standard infrarenal endovascular aneurysm repair (EVAR); however, no prior studies with new-generation devices have been able to determine an association between T3EL and clinical outcomes. Here we examine T3EL within the Society for Vascular Surgery Vascular Quality Initiative (VQI) to define rates of occurrence, rates and modes of reintervention, and clinical consequences of these endoleaks.

Design and setting

Participants receiving infrarenal EVAR in the VQI from January 2003 to September 2018 were analyzed in a retrospective cohort study.

Participants

Of 42 246 entries in the EVAR procedural registry, 41 604 had complete procedural information and were included in analysis. Of these, 36 082 had long-term follow-up, and 26 422 had follow-up (9-21 months per VQI reporting standards) with complete endoleak data recorded.

Interventions

All patients included in this study underwent an infrarenal EVAR.

Results

Within the VQI database, the rate of T3EL in infrarenal EVAR during index hospitalization was 0.37% (n=157/41 604), of which 85% were due to midgraft separation and 15% were due to fabric disruptions. Out of the 157 index hospitalization T3ELs, 4.5% (n=7) received procedural reintervention during that hospitalization, which accounted for 1% of all index hospitalization reinterventions. During the 21-month follow-up, the rate of incident T3EL was 0.7% (n=205/26 422), which accounted for 5% of all endoleaks seen during follow-up. Reinterventions for incident T3EL at follow-up were done in 30 patients (rate 0.1%), which accounted for 9% of endoleak reinterventions and 3.3% of all reinterventions. The presence of incident T3EL found during follow-up was associated with a significant decrease in 5-year survival (74% vs 80%, respectively; p=0.041) in Kaplan-Meier analysis.

Conclusion

T3ELs rates at placement and follow-up remain low; however, the majority reported in long-term follow-up are incident and these incident endoleaks are associated with decreased survival in EVAR.

Impact of Thoracic Endografting on the Hemodynamics of the Native Aorta: Pre- and Postoperative Assessments of Wall Shear Stress and Vorticity Using Computational Fluid Dynamics

PURPOSE

To quantify the hemodynamic consequences of thoracic endovascular aortic repair (TEVAR) by comparing the preoperative and postoperative wall shear stress (WSS) and vorticity profiles on computational fluid dynamics (CFD) simulations.

MATERIALS AND METHODS

The pre- and postoperative computed tomography (CT) scans from 20 consecutive patients (median age 69 years, range 20-87) treated for different thoracic aortic pathologies (11 aneurysms, 5 false aneurysms, 3 penetrating ulcers, and 1 traumatic aortic rupture) were segmented to construct patient-specific CFD models using a meshless code. The simulations were run over the cardiac cycle, and the WSS and vorticity values measured at the proximal and distal landing zones were compared.

RESULTS

The CFD runs provided 4-dimensional simulations of blood flow in all patients. WSS and vorticity profiles at the proximal landing zone (located in zones 0-3 in 15 patients) varied in 18 and 20 of the cases, respectively; WSS was increased in 11 cases and the vorticity in 9. Pre- and postoperative WSS median values were 4.19 and 4.90 Pa, respectively. Vorticity median values were 40.38 and 39.17 Hz, respectively.

CONCLUSION

TEVAR induces functional alterations in the native thoracic aorta, though the prognostic significance of these changes is still unknown. CFD appears to be a valuable tool to explore aortic hemodynamics, and its application in a larger series would help define a predictive role for these hemodynamic assessments.

Descending thoracic endovascular aortic repair does not require cardiothoracic surgery support

Objective

Descending thoracic endovascular aneurysm repair (D-TEVAR) is often performed by vascular surgeons. At many institutions, cardiothoracic surgery support is required for an elective TEVAR to take place. Oftentimes, this means a dedicated cardiopulmonary bypass team must be available. This study aims to investigate that TEVAR is a safe procedure that does not require such a resource-intensive “back-up plan.”

Methods

This is a retrospective analysis of data collected from March 2014 to January 2018 of 18 patients who underwent TEVAR at a tertiary care facility with a level I trauma center. There were 11 males and 7 females with an average age of 68.8 years old (range 19–97; SD ± 19.52). The average body mass index (BMI) was 24.7 kg/m2 (range 16.8–35; SD ±4.67). Nine were never smokers, four were former smokers, and five were currently smoking at the time of the procedure. The most common presenting symptom prior to intervention was chest pain ( n = 10), followed by cough/dyspnea ( n = 5), back pain ( n = 3), and trauma ( n = 2).

Results

The average maximum diameter of the thoracic aortic aneurysms (TAA) treated with TEVAR was 5.49 cm ( n = 7; range 4.3–6.7; SD ± 0.855). Six patients had Stanford Type B aortic dissections. Two patients with TAAs had concomitant, rapidly expanding aortic ulcers. Two patients had traumatic pseudoaneurysms, one of which ruptured prior to TEVAR. One patient had an expanding 1.9 × 1.8 cm saccular pseudoaneurysm of the aortic arch. The mean follow-up time was 69.2 weeks ( n = 17; range 3–166; SD ± 62.67), and one patient did not follow up following their initial TEVAR procedure. Of the 18 patients who received TEVAR, there were no major complications. Two patients experienced a type II endoleak. No patients required conversion to an open procedure, nor did any patients necessitate intervention by cardiothoracic surgery or cardiopulmonary bypass support.

Conclusion

These data suggest that cardiothoracic surgery support is not required for descending thoracic endovascular aneurysm repair (D-TEVAR). Further research is warranted on the risk factors associated with open conversion during these procedures.

Iliac Stent Migration during Thoracic Endovascular Aortic Aneurysm Repair Resulting in Functional Coarctation

Iliac arterial disease, unfavorable anatomy, and prior stenting all pose challenges to access in endovascular abdominal aortic repair (EVAR) and thoracic aortic repair (TEVAR). Iliac access injury during T/EVAR may lead to rupture, dissection, thrombosis, or distal ischemia. Some have advocated iliac stent prior to T/EVAR in patients with suboptimal iliac access. The rate of complication and iliac stent migration during subsequent T/EVAR is undocumented. This case report describes a unique instance of self-expanding iliac stent migration during TEVAR which pinched the thoracic aortic endograft causing functional aortic coarctation.

Feeding Arteries of the Spinal Cord at CT Angiography before and after Thoracic Aortic Endografting

Purpose:

To study the visualization of spinal cord feeding arteries in patients with complex thoracic aortic pathology undergoing endovascular aortic repair (EVAR) using an optimized protocol for multislice computed tomographic angiography (MSCTA).

Methods:

Eighteen consecutive patients (13 men; mean age 63 years, range 45–79) with aortic type B dissections (n=5), chronic expanding aortic dissections (n=5), thoracic aortic aneurysms (n=6), or penetrating aortic ulcers (n=2) underwent 16-slice CTA before and after (mean interval 9 days) EVAR. Pulse rate and neurological status were documented. Quantitative density measurements were taken at regions of interest (ROI) in the ascending thoracic aorta and at the level of the diaphragm. Two experienced radiologists qualitatively assessed the posterior intercostal arteries (PIA; fully visible, partially visible, non-visible), dorsal branches (DB; visible/non-visible), and artery of Adamkiewicz (AKA; visible/non-visible) on multiplanar reformations and maximum intensity projection reconstructions.

Results:

MSCTA was performed successfully in 17/18 patients before and after EVAR (1 patient was excluded after EVAR owing to rising creatinine levels). Before EVAR, MSCTA revealed 197/203 PIAs within the stented area, of which 179 were fully and 18 partially visible. No significant (p=0.37) difference was noted for overall PIA detection within the stented area on post-EVAR MSCTA (185/203 PIA), although only 124 were fully and 61 partially visible. Similar results were obtained for DB visualization. The AKA were seen in 10/17 patients pre EVAR and 9/17 post EVAR. In 2 patients, the AKA was localized within the stented aortic segment. ROI analysis revealed contrast densities of 427±89 HU and 398±84 HU on pre- and post-EVAR MSCTA, respectively. No neurological events were observed.

Conclusion:

The majority of posterior intercostal arteries and dorsal branches remain open after EVAR due to retrograde perfusion. High-resolution MSCTA permits accurate pre-and post-EVAR visualization of spinal cord feeding arteries in patients with thoracic aortic pathology.

Endovascular treatment of acquired atheromatous aortic arch coarctation

Acquired aortic coarctation is a rare condition. Its treatment using a percutaneous approach can be challenging, especially when severe calcifications and concomitant aneurysmal disease are present. We report a patient with symptomatic thoracic aorta acquired coarctation and aneurysm that was successfully treated using endovascular technique. After left subclavian artery transposition, a self-expanding endograft was implanted percutaneously, with complete abolishment of the transaortic gradient. Follow-up evaluation at 12 months revealed perfect position of the endograft, persistent reduction of the coarctation, and exclusion of the concomitant aneurysm. A noninvasive pressure reading demonstrated significant systemic blood pressure reduction, with no change in antihypertensive medications.

Haemodynamic imaging of thoracic stent-grafts by computational fluid dynamics (CFD): presentation of a patient-specific method combining magnetic resonance imaging and numerical simulations

OBJECTIVES

In the last decade, there was been increasing interest in finding imaging techniques able to provide a functional vascular imaging of the thoracic aorta. The purpose of this paper is to present an imaging method combining magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to obtain a patient-specific haemodynamic analysis of patients treated by thoracic endovascular aortic repair (TEVAR).

METHODS

MRI was used to obtain boundary conditions. MR angiography (MRA) was followed by cardiac-gated cine sequences which covered the whole thoracic aorta. Phase contrast imaging provided the inlet and outlet profiles. A CFD mesh generator was used to model the arterial morphology, and wall movements were imposed according to the cine imaging. CFD runs were processed using the finite volume (FV) method assuming blood as a homogeneous Newtonian fluid.

RESULTS

Twenty patients (14 men; mean age 62.2 years) with different aortic lesions were evaluated. Four-dimensional mapping of velocity and wall shear stress were obtained, depicting different patterns of flow (laminar, turbulent, stenosis-like) and local alterations of parietal stress in-stent and along the native aorta.

CONCLUSIONS

A computational method using a combined approach with MRI appears feasible and seems promising to provide detailed functional analysis of thoracic aorta after stent-graft implantation.

KEY POINTS

• Functional vascular imaging of the thoracic aorta offers new diagnostic opportunities • CFD can model vascular haemodynamics for clinical aortic problems • Combining CFD with MRI offers patient specific method of aortic analysis • Haemodynamic analysis of stent-grafts could improve clinical management and follow-up.

Roles for specialty societies and vascular surgeons in accountable care organizations

With the passage of the Affordable Care Act, accountable care organizations (ACOs) represent a new paradigm in healthcare payment reform. Designed to limit growth in spending while preserving quality, these organizations aim to incant physicians to lower costs by returning a portion of the savings realized by cost-effective, evidence-based care back to the ACO. In this review, first, we will explore the development of ACOs within the context of prior attempts to control Medicare spending, such as the sustainable growth rate and managed care organizations. Second, we describe the evolution of ACOs, the demonstration projects that established their feasibility, and their current organizational structure. Third, because quality metrics are central to the use and implementation of ACOs, we describe current efforts to design, collect, and interpret quality metrics in vascular surgery. And fourth, because a "seat at the table" will be an important key to success for vascular surgeons in these efforts, we discuss how vascular surgeons can participate and lead efforts within ACOs.

Electromagnetic navigation for thoracic aortic stent-graft deployment: a pilot study in swine

PURPOSE

To determine the feasibility of electromagnetic tracking as a method to augment conventional imaging guidance for the safe delivery, precise positioning, and accurate deployment of thoracic aortic endografts.

MATERIALS AND METHODS

Custom guide wires were fabricated, and the delivery catheters for thoracic aortic endoprostheses were retrofitted with integrated electromagnetic coil sensors to enable real-time endovascular tracking. Preprocedure thoracic computed tomographic (CT) angiograms were obtained after the placement of fiducial skin patches on the chest wall of three anesthetized swine, enabling automatic registration. The stent-graft deployment location target near the subclavian artery was selected on the preprocedure CT angiogram. Two steps were analyzed: advancing a tracked glidewire to the aortic arch and positioning the tracked stent-graft assembly by using electromagnetic guidance alone. Multiple CT scans were obtained to evaluate the accuracy of the electromagnetic tracking system by measuring the target registration error, which compared the actual position of the tracked devices to the displayed "virtual" electromagnetic-tracked position. Postdeployment CT angiography and necropsy helped confirm stent-graft position and subclavian artery patency.

RESULTS

A stent-graft was successfully delivered and deployed in each of the three animals by using real-time electromagnetic tracking alone. The mean fiducial registration error with autoregistration was 1.5 mm. Sixteen comparative scans were obtained to determine the target registration error, which was 4.3 mm +/- 0.97 (range, 3.0-6.0 mm) for the glidewire sensor coil. The mean target registration error for the stent-graft delivery catheter sensor coil was 2.6 mm +/- 0.7 (range, 1.9-3.8 mm). The mean deployment error for the stent-graft, defined as deployment deviation from the target, was 2.6 mm +/- 3.0.

CONCLUSIONS

Delivery and deployment of customized thoracic stent-grafts with use of electromagnetic tracking alone is feasible and accurate in swine. Combining endovascular electromagnetic tracking with conventional fluoroscopy may further improve accuracy and be a more realistic multimodality approach.

Training the next generation of vascular specialists: current status and future perspectives

Several challenges exist with respect to training the current and next generation of vascular specialists. Current advances in technology have led to changes in the length and type of training required to master new endovascular techniques. At the same time, the number of open surgical cases being provided to trainees may not be sufficient to allow them to manage complex open procedures. This growth is occurring at a time when increased external pressures are being applied to shorten training programs. Finally, the next generation of vascular specialists will come from medical students who are accruing a large educational debt during their course of training. Vascular specialists outside the US have already begun to successfully deal with many of these issues, and insight can be gained from their successes and difficulties. In this article, we review the current status of training for vascular and endovascular specialists and discuss the need for changes in current US training paradigms. While this will touch on initiatives in other specialties, including cardiology, vascular medicine, and interventional and neuroradiology, we will focus primarily on changes that are occurring with respect to the training of surgical specialists who manage vascular disease.

Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines

OBJECTIVE

Recently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study's purpose was to determine whether these requirements are valid by reviewing three surgeons' learning curves with thoracic aortic endovascular repairs.

METHODS

Between 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon's learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success.

RESULTS

These 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon's cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients.

CONCLUSION

This study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases.

Vascular Surgery Training after Primary Certification: Where We Go from Here

Program directors in vascular surgery have an increasingly complex set of responsibilities in the management of a vascular surgery residency, now that primary certification has been approved for vascular surgery and new training paradigms have been created in addition to the previous sequential training and certification in both general and vascular surgery. With the availability of new training paradigms, such as the 3+3 curriculum or entrance into a vascular residency program of 5 or 6 years directly out of medical school, the program director will become responsible for ensuring adequate training in basic surgical principals as well in the management of vascular pathology. Areas of added responsibility will include recruiting trainees, maintaining training case volumes, developing effective educational curricula and certifying the quality of the residents. This article discusses these tasks in detail, identifying special problem areas, such as changing lifestyle expectations, particularly in recruiting women, now approaching one half of medical students; expansion to meet the increasing need for vascular surgeons in the future as the population ages; funding vascular fellowship training; maintaining open surgical case loads while providing the facilities and supervision for adequate endovascular surgical training; providing a useful experience in both noninvasive vascular diagnosis and nonoperative management of vascular disease--in short, an experience that will result in Board certification and obtaining hospital privileges and a career that satisfies their choice of vascular surgery as a specialty.

Advanced Endovascular Training for Vascular Residents: What More Do We Need?

In the 25 years that formalized vascular surgery training and certification has been, in effect, the treatment of patients with peripheral vascular disease has undergone dramatic changes, largely due to the emergence of a wide variety of endoluminal techniques and devices that enable minimally invasive treatment of conditions that formerly required operative intervention. Unfortunately, vascular surgeons, for the most part, were painfully slow to embrace these new and evolving technologies, which became increasingly complex as they expanded to treat virtually all vascular maladies in all peripheral vascular territories. Not surprisingly, this left vascular surgeons disadvantaged relative to other disciplines for whom these techniques were more familiar, and we have spent the better part of the last decade playing catch-up to master them and regain our role as the only specialty qualified to offer all types of therapies to our patients with vascular disease. This has caused some to question what changes need to be made in our vascular surgery training paradigm for our new trainees to attain and maintain a preeminent role in the evaluation and treatment of patients with peripheral vascular disease. While the knee-jerk response is to consider special or supplemental training programs for these advanced techniques, or even certificates of added qualifications for the more challenging of them, such as carotid stenting, we believe that all that is really needed is for the vascular surgical community as a whole, and particularly those faculty in training programs, to truly embrace these new technologies and apply them to the patients they are already rendering care to. Given the prevalence of vascular disease and overall wealth of clinical material already present in most training programs, the simple willingness to apply endoluminal therapies to our existing patient populations is all that would really be needed to insure that all future graduates of vascular surgery training programs are fully competent in all of the current endoluminal therapies and well-positioned to continue to evolve with the field. The real question to be considering, which is beyond the focus of this article, is how we are to maintain our open surgical skills in the era of minimally invasive treatment of vascular disease.