Simulation of carotid artery stenting reduces training procedure and fluoroscopy times.

OBJECTIVE: Outcomes from carotid artery stenting (CAS) are related to experience and technical expertise of the operator. Simulation of CAS may enhance clinical proficiency. We interrogated the impact of endovascular simulation of CAS procedures in operators who are at various stages of training. METHODS: Twelve trainees (students [n = 4]; junior surgery residents, postgraduate year [PGY] 1-3 [n = 4]; and senior surgery residents or fellows, PGY 4-7 [n = 4]) were apprised of characteristics of an endovascular simulator and CAS procedures. This was followed by four independent sessions that were assessed for objective measures including procedure and fluoroscopy times and contrast agent use. A qualitative analysis grading steps of CAS by two observers using a Likert scale was performed. One-way analysis of variance and paired t-tests were employed for data analysis. RESULTS: For all participants (n = 12), procedure times (mean, 920 ± 279 seconds for the first session vs 454 ± 156 seconds for the fourth session; P < .01; confidence interval [CI], 315-621) and fluoroscopy cumulative times (mean, 421 ± 230 seconds for the first session vs 222 ± 102 seconds for the fourth session; P < .01; CI, 78-285) decreased with progression of cases. Students and PGY 1-3 residents decreased their procedure times significantly in comparison of initial and final sessions (P < .05 and P < .01, respectively). For all groups, fluoroscopy cumulative times were reduced, and this decrement was significant in the PGY 1-3 cohort (mean, 444 ± 8 seconds for the first session vs 265 ± 51 seconds for the fourth session; P < .01; CI, 81-276). Initial CAS procedure times were significantly different between groups (P < .05), but this was observed to resolve by the final case at study completion. Qualitatively, the Likert scores of students and PGY 1-3 residents significantly improved with case repetition, specifically in the following steps: (1) cannulation of common carotid artery and (2) sizing and deployment of embolic protection device. Senior operators (PGY 4-7) demonstrated consistently better performance overall with minimal change in scoring with case repetition. CONCLUSIONS: Practice leads to improvements in endovascular simulator procedure and fluoroscopy times, especially for more novice trainees. Initial operator performance gaps can be approximated with a few sessions to expected proficiency. Incorporation of endovascular simulators in residency training may assist in shortening the learning curve in rarer endovascular procedures.

Endovascular aneurysm repair simulation can lead to decreased fluoroscopy time and accurately delineate the proximal seal zone.

BACKGROUND: The use of simulators for endovascular aneurysm repair (EVAR) is not widespread. We examined whether simulation could improve procedural variables, including operative time and optimizing proximal seal. For the latter, we compared suprarenal vs infrarenal fixation endografts, right femoral vs left femoral main body access, and increasing angulation of the proximal aortic neck. METHODS: Computed tomography angiography was obtained from 18 patients who underwent EVAR at a single institution. Patient cases were uploaded to the ANGIO Mentor endovascular simulator (Simbionix, Cleveland, Ohio) allowing for three-dimensional reconstruction and adapted for simulation with suprarenal fixation (Endurant II; Medtronic Inc, Minneapolis, Minn) and infrarenal fixation (C3; W. L. Gore & Associates Inc, Newark, Del) deployment systems. Three EVAR novices and three experienced surgeons performed 18 cases from each side with each device in randomized order (n = 72 simulations/participant). The cases were stratified into three groups according to the degree of infrarenal angulation: 0° to 20°, 21° to 40°, and 41° to 66°. Statistical analysis used paired t-test and one-way analysis of variance. RESULTS: Mean fluoroscopy time for participants decreased by 48.6% (P < .0001), and total procedure time decreased by 33.8% (P < .0001) when initial cases were compared with final cases. When stent deployment accuracy was evaluated across all cases, seal zone coverage in highly angulated aortic necks was significantly decreased. The infrarenal device resulted in mean aortic neck zone coverage of 91.9%, 89.4%, and 75.4% (P < .0001 by one-way analysis of variance), whereas the suprarenal device yielded 92.9%, 88.7%, and 71.5% (P < .0001) for the 0° to 20°, 21° to 40°, and 41° to 66° cases, respectively. Suprarenal fixation did not increase seal zone coverage. The side of femoral access for the main body did not influence proximal seal zone coverage regardless of infrarenal angulation. CONCLUSIONS: Simulation of EVAR leads to decreased fluoroscopy times for novice and experienced operators. Side of femoral access did not affect precision of proximal endograft landing. The angulated aortic neck leads to decreased proximal seal zone coverage regardless of infrarenal or suprarenal fixation devices.

Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries.

PURPOSE: To examine the hypothesis that alternative flush media could be used for lower extremity optical coherence tomography (OCT) imaging in long lesions that would normally require excessive use of contrast. METHODS: The OPTical Imaging Measurement of Intravascular Solution Efficacy (OPTIMISE) trial was a single-center, prospective study (ClinicalTrials.gov identifier NCT01743872) that enrolled 23 patients (mean age 68±11 years; 14 men) undergoing endovascular intervention involving the superficial femoral artery. Four flush media (heparinized saline, dextran, carbon dioxide, and contrast) were used in succession in random order for each image pullback. Quality was defined as ≥270° visualization of vessel wall layers from each axial image. Mean proportions (± standard deviation) of image quality for each flush medium were assessed using 1-way analysis of variance and are reported with the 95% confidence intervals (CI). RESULTS: Four OCT catheters failed, leaving 19 patients who completed the OCT imaging protocol; from this cohort, 51 highest quality runs were selected for analysis. Average vessel diameter was 3.99±1.01 mm. OCT imaging allowed 10- to 15-µm resolution of the lumen border, with diminishing quality as vessel diameter increased. Plaque characterization revealed fibrotic lesions. Mean proportions of image quality were dextran 87.2%±12% (95% CI 0.81 to 0.94), heparinized saline 74.3%±24.8% (95% CI 0.66 to 0.93), contrast 70.1%±30.5% (95% CI 0.52 to 0.88), and carbon dioxide 10.0%±10.4% (95% CI 0.00 to 0.26). Dextran, saline, and contrast provided better quality than carbon dioxide (p<0.001). CONCLUSION: OCT is feasible in peripheral vessels <5 mm in diameter. Dextran or saline flush media can allow lesion characterization, avoiding iodinated contrast. Carbon dioxide is inadequate for peripheral OCT imaging. Axial imaging may aid in enhancing durability of peripheral endovascular interventions.

Divergent effects of T cell costimulation and inflammatory cytokine production on autoimmune peripheral neuropathy provoked by Aire deficiency.

Chronic inflammatory demyelinating polyneuropathy results from autoimmune destruction of the peripheral nervous system and is a component of the multiorgan autoimmunity syndrome that results from Aire gene mutations in humans. In parallel, peripheral nervous system autoimmunity resembling chronic inflammatory demyelinating polyneuropathy develops spontaneously in NOD mice with a partial loss of Aire function (NOD.Aire(GW/+) mice) and is a T cell-mediated disease. In this study, we analyze how key aspects of T cell activation and function modulate disease development in Aire-deficient mice. We show that genetic ablation of the Th1 cytokine IFN-γ completely prevents clinical and electrophysiological evidence of neuropathy in NOD.Aire(GW/+) mice. IFN-γ deficiency is associated with absence of immune infiltration and decreased expression of the T cell chemoattractant IP-10 in sciatic nerves. Thus, IFN-γ is absolutely required for the development of autoimmune peripheral neuropathy in NOD.Aire(GW/+) mice. Because IFN-γ secretion is enhanced by B7-CD28 costimulation of T cells, we sought to determine the effects of these costimulatory molecules on neuropathy development. Surprisingly, B7-2 deficiency accelerated neuropathy development in NOD.Aire(GW/+) mice, and Ab blockade of both B7-1 and B7-2 resulted in fulminant, early-onset neuropathy. Thus, in contrast to IFN-γ, B7-2 alone and B7-1/B7-2 in combination function to ameliorate neuropathy development in NOD.Aire(GW/+) mice. Together, these findings reveal distinct and opposing effects of the T cell costimulatory pathway and IFN-γ production on the pathogenesis of autoimmune peripheral neuropathy.

The liver twist: A case of accessory liver lobe torsion presenting after mild trauma.

An accessory liver lobe is a congenital anomaly of hepatic tissue most commonly due to embryonic heteroplasia. Rarely, accessory liver lobes can undergo torsion and present as an acute surgical emergency. Although common in certain animals, there are only a few reported cases of accessory lobe torsion in humans. We report a multi-modality radiographic diagnosis of an acute torsion and subsequent infarct of an accessory liver lobe following minor trauma in a 29-year old male patient.

Endovascular Simulation Leads to Efficiency and Competence in Thoracic Endovascular Aortic Repair Procedures.

OBJECTIVE: Endovascular interventions such as thoracic endovascular aortic repair (TEVAR) have largely replaced invasive open procedures, and have been demonstrated to be effective in treating patients. Our study used endovascular simulation to assess the effect of TEVAR rehearsal on surgical trainees at different levels in training. DESIGN: Participants were oriented on an endovascular simulator and subsequently a simulated TEVAR was performed during 4 separate sessions over a 1-month period. Metrics included total procedure/fluoroscopy time and volume of contrast used. Likert scale qualitative analysis evaluated participant׳s skills involving major procedural steps. Analysis of data across cohorts included 1-way analysis of variance, Kruskal-Wallis, and paired t-tests. SETTING: All data were collected at University Hospitals-Case Medical Center, Cleveland, OH. PARTICIPANTS: In all, 12 trainees in 3 cohorts (student, surgery resident postgraduate year [PGY] 1-3, surgery resident/fellow PGY 4-7, n = 4 each) were recruited. RESULTS: All trainees reduced total procedure time (mean = 537 ± 148 vs 269 ± 66s, first session vs fourth, P < 0.05, CI: 195-341) and fluoroscopy time (mean = 201 ± 74 vs 110 ± 37s, P < 0.05, CI: 51-132) with TEVAR case progression. The student cohort decreased procedure time from 551 ± 84s to 313 ± 65s (P < 0.05, CI: 189-287) whereas PGYs 1 to 3 decreased procedure time from 591 ± 149s to 264 ± 29s (P < 0.05, CI: 113-541). Use of contrast decreased over time, but the difference was not significant. Participants acquired proficiency after a few runs in most steps of the procedure. The average qualitative score for all groups combined improved significantly (P < 0.03). PGY 4 to 7 trainees had higher technical scores but this was not statistically significant. The initial gap in junior vs senior trainee performance narrowed after a few practice sessions in all aspects evaluated. CONCLUSIONS: TEVAR rehearsal on an endovascular simulator can reduce overall procedure and fluoroscopy time, independent of trainee skill level or experience, as well as improve subjective measures of technical success. Further studies are needed to compare simulator performance to outcomes in live cases.

Aire deficiency promotes TRP-1-specific immune rejection of melanoma.

The thymic transcription factor autoimmune regulator (Aire) prevents autoimmunity in part by promoting expression of tissue-specific self-antigens, which include many cancer antigens. For example, AIRE-deficient patients are predisposed to vitiligo, an autoimmune disease of melanocytes that is often triggered by efficacious immunotherapies against melanoma. Therefore, we hypothesized that Aire deficiency in mice may elevate immune responses to cancer and provide insights into how such responses might be triggered. In this study, we show that Aire deficiency decreases thymic expression of TRP-1 (TYRP1), which is a self-antigen in melanocytes and a cancer antigen in melanomas. Aire deficiency resulted in defective negative selection of TRP-1-specific T cells without affecting thymic numbers of regulatory T cells. Aire-deficient mice displayed elevated T-cell immune responses that were associated with suppression of melanoma outgrowth. Furthermore, transplantation of Aire-deficient thymic stroma was sufficient to confer more effective immune rejection of melanoma in an otherwise Aire wild-type host. Together, our work showed how Aire deficiency can enhance immune responses against melanoma and how manipulating TRP-1-specific T-cell negative selection may offer a logical strategy to enhance immune rejection of melanoma.