Theatrical performance in medical education: A fast-track differential approach of emergency cases.

INTRODUCTION: The idea of implementing theatrical acts in medical education has recently been gaining attention, with the inclusion of art-based programs in medical curricula being a growing trend. This study aimed to present an innovative pilot program of presenting medical emergencies through theatrical presentation. MATERIALS AND METHODS: Students-members of the theatrical team of Democritus University of Thrace and the Scientific Society of Hellenic Medical Students were appointed into eight groups, supervised by a clinical tutor. The groups were given four weeks to prepare scenarios for eight different medical emergencies and organize a theatrical sketch accordingly. A 25-item questionnaire was formed and distributed to the audience. Each theatrical act lasted 10 min, followed by a 10 min discussion between the tutors and the audience. After the event, the impressions of the attendees were documented in the questionnaire as responses on a Likert scale from one (strongly disagree) to five (strongly agree). RESULTS: Two hundred and thirty-two fully completed questionnaires were returned. The contribution of theatrical presentation to medical education was widely acknowledged (Likert score 4.14 ± 0.68). Theatrical seminars were not deemed insufficient to provide medical information (disagreed or strongly disagreed 53.8 % and 12.1 %, respectively). Most students were optimistic about the long-term maintenance of the theatrical-aided knowledge, with the majority of attendees (52.1 %) adapting a more favorable response after the seminar (p <0.001). The students' efficacy to recognize medical emergencies was improved (from 2.96 to 3.43, p <0.001). CONCLUSION: Students find the theatrical approach of emergency cases entertaining and educational, facilitating teaching in medicine and enhancing their efficacy to recognize medical emergencies and the commonest pitfalls in their diagnosis and management. Such events may be established as a supplementary educational tools to the classical amphitheatric didactic lectures. Future studies with specific objective tools are needed to validate the abovementioned tasks. HIPPOKRATIA 2020, 24(3): 127-132.

Novel Oral Anticoagulants in Peripheral Artery Disease: Current Evidence.

BACKGROUND: Peripheral artery disease is a common manifestation of systemic atherosclerosis which strongly correlates to cardiovascular morbidity and mortality. In addition, the progression of peripheral artery disease leads to an increased risk of limb loss. In order to reduce these events, the benchmark of treatment and research over the last years has been the antiplatelet therapy which aims at inhibition of platelet aggregation. Over the last years, new studies combining antiplatelet agents in different therapeutic schemes have been proven efficacious. Unfortunately, patients remain still at high risk of CV events. Novel Oral Anticoagulants have been introduced as alternatives to warfarin, in the prevention and treatment of venous thromboembolism. The rationale of using medication which acts on platelet activation and the coagulation pathway of thrombosis has led investigators to examine the role of Noac's in preventing CV events in patients with peripheral artery disease, stable or unstable. METHODS: The aim of this study is to review the current evidence with respect to recently published studies concerning the use of Novel anticoagulants in peripheral artery disease. RESULTS: The Compass trial has shown that a combination of rivaroxaban with traditional therapy may produce promising results in reducing amputation rates, stroke, cardiac events, and mortality, however, there are still safety issues with bleeding requiring acute care. The ePAD study has provided us with insight concerning safety and efficacy after peripheral angioplasty or stenting and actually the need for further research. The Voyager Pad study, following the steps of Compass, is studying the effect and safety of the addition of rivaroxaban to traditional therapy in the highest risk population aka patients undergoing peripheral revascularization. The evidence concerning patients with concomitant atrial fibrillation appears to be insufficient, however, recent guidelines propose the use of novel oral anticoagulants. CONCLUSION: For the time being, novel oral anticoagulants in combination with aspirin may provide an alternative treatment in PAD, however, it is deemed necessary to identify patient subgroups who will benefit the most.

Lack of evidence for use of heparin-bonded grafts in access surgery: a meta-analysis.

The aim of this study was to evaluate the efficacy of heparin-bonded vascular grafts to offer improved outcomes compared with standard prosthetic grafts in access surgery. A systematic review and meta-analysis was performed and eight studies (seven observational studies and one randomized controlled trial) were included. The pooled 6-month and 1-year primary patency was not significantly different between heparin-bonded arteriovenous (AV) grafts and standard prosthetic AV grafts in seven studies reporting on 1,209 access procedures. The assisted primary patency and secondary patency at 1-year was not significantly different either. Heparin-bonded AV grafts offer no distinct advantage over standard prosthetic AV grafts and their preferential use in access surgery cannot be recommended based on the available evidence.

The Necessity for Routine Pre-operative Ultrasound Mapping Before Arteriovenous Fistula Creation: A Meta-analysis.

OBJECTIVE/BACKGROUND: Existing guidelines suggest routine use of pre-operative color Doppler ultrasound (DUS) vessel mapping before the creation of arteriovenous fistulae (AVF); however, there is controversy about its benefit over traditional clinical examination or selective ultrasound use. METHODS: This was a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing routine DUS mapping before the creation of AVF with patients for whom the decision for AVF placement was based on clinical examination and selective ultrasound use. A search of MEDLINE/PubMed, SCOPUS, and the Cochrane Library was carried out in June 2014. The analyzed outcome measures were the immediate failure rate and the early/midterm adequacy of the fistula for hemodialysis. Additionally, assessment of the methodological quality of the included studies was carried out. RESULTS: Five studies (574 patients) were analyzed. A random effects model was used to pool the data. The pooled odds ratio (OR) for the immediate failure rate was 0.32 (95% confidence interval [CI] 0.17-0.60; p < .01), which was significantly in favor of the DUS mapping group. The pooled OR for the early/midterm adequacy for hemodialysis was 0.66 (95% CI 0.42-1.03; p = .06), with a trend in favor of the DUS mapping group; however, subgroup analysis revealed that routine DUS mapping was more beneficial than selective DUS (p < .05). CONCLUSION: The available evidence, based mainly on moderate quality RCTs, suggests that the pre-operative clinical examination should always be supplemented with routine DUS mapping before AVF creation. This policy avoids negative surgical explorations and significantly reduces the immediate AVF failure rate.

Computational estimation of the influence of the main body-to-iliac limb length ratio on the displacement forces acting on an aortic endograft. Theoretical application to Bolton Treovance® Abdominal Stent-Graft.

AIM: The influence of the relative iliac limb length of an endograft (EG) on the displacements forces (DF) predisposing to adverse effects are under-appreciated in the literature. Therefore, we conducted a computational study to estimate the magnitude of the DF acting over an entire reconstructed EG and its counterparts for a range of main body-to-iliac limb length (L1/L2) ratios. METHODS: A customary bifurcated 3D model was computationally created and meshed using the commercially available ANSYS ICEM (Ansys Inc., Canonsburg, PA, USA) software. Accordingly, Fluid Structure Interaction was used to estimate the DF. The total length of the EG was kept constant, while the L1/L2 ratio ranged from 0.3 to 1.5. RESULTS: The increase in L1/L2 slightly affected the DF on the EG (ranging from 3.8 to 4.1 N) and its bifurcation (4.0 to 4.6 N). However, the forces exerted at the iliac sites were strongly affected by the L1/L2 values (ranging from 0.9 to 2.2 N), showing a parabolic pattern with a minimum for 0.6 ratio. CONCLUSION: It is suggested that the hemodynamic effect of the relative limb lengths should not be considered negligible. A high main body-to-iliac limb length ratio seems to favor hemodynamically a low bifurcation but it attenuates the main body-iliac limbs modular stability. Further clinical studies should investigate the relevant value of these findings. The Bolton Treovance(®) device is presented as a representative, improved stent-graft design that takes into account these hemodynamic parameters in order to achieve a promising, improved clinical performance.

Antiplatelet treatment and prothrombotic diathesis following endovascular abdominal aortic aneurysm repair.

Prothrombotic diathesis expressed by elevated levels of coagulation-specific biomarkers has been reported in patients with abdominal aortic aneurysm (AAA) and after AAA endovascular repair (EVAR). This study investigates the effect of antiplatelet agents (APLs) on the prothrombotic diathesis in the post-EVAR period. Forty elective EVAR patients had thrombin-antithrombin complex, d-dimer, fibrinopeptide A, and high-sensitivity C-reactive protein measured before, at 24 hours, 1 month, and 6 months after EVAR. Patients receiving APLs postoperatively were compared with those not receiving APLs. All biomarkers were above the normal limits preoperatively and increased significantly 24 hours postoperatively followed by a drop at 1 and 6 months. No statistically significant changes were noted among patients receiving APLs in comparison with those not receiving APLs. The preoperative and postoperative prothrombotic diathesis of AAA following EVAR was confirmed in line with other reports. There was however no significant alteration of the examined biomarkers in patients receiving APLs.

The hemodynamic impact of misalignment of fenestrated endografts: a computational study.

OBJECTIVE: The hemodynamic consequences of misaligned stent-grafts (SG) in fenestrated endografts (EG) have not been adequately studied. Our aim was to study the hemodynamic effects of positional variations of SG, investigating the potential influence on the total displacement forces acting on the EG and the shear stress values at the stented segments. METHODS: This was a computational study. An idealized EG model with two renal fenestrations was computationally reconstructed and centrally extended up to the suprarenal level to treat a suprarenal aneurysm. The misalignment of SG was represented by a variable take-off angle between the SG and the EG centerline axis, corresponding to angles of 90°, 176°, 142°, 38°, and 4°, respectively. Accordingly, the maximum EG displacement forces and the shear stress within the stented segments were calculated, using commercially available software. RESULTS: The variable positions of the SG caused no effect on the maximum displacement force acting on the EG, being quite steady and equal to 5.55 N. On the contrary, the values of maximum shear stress acting on the stented segments were influenced by their orientation. The narrow transition zone between the distal end of the mating stent and the target artery showed higher stresses than any other segment. The right-angle take off SG position (90°) was associated with the lowest stresses (12.5 Pa), whereas the highest values were detected at 38° and 142° (16.5 and 16.1 Pa, respectively). The vessel segments distal to the SG exhibited constantly lower stress values (1.9-2.2 Pa) than any other segment. CONCLUSION: We detected differences in the values of shear stress exerted on the stented arteries, depending on different positions that SG can adapt after the deployment of fenestrated EG. The pathophysiologic implication of our findings and their potential association with clinical events deserve further investigation and clinical validation.

Studying the expansion of small abdominal aortic aneurysms: is there a role for peak wall stress?

AIM: The aim of this paper was to study the characteristics of three distending small abdominal aortic aneurysms (AAAs), with an increase in maximal diameter from 5 to 5.5 cm or above. METHODS: Peak Wall Stress (PWS) in the presence and absence of intraluminal thrombus (ILT) was evaluated in 3 cases of small AAAs (5 cm), at initial presentation and after their expansion, at maximum diameters ≥5.5 cm using finite element analysis. Furthermore, AAA sac volume (Vsac), the percentage volume of ILT (ILT%) and the percentage change of Vsac (ΔV%) and ILT (ILT%) were estimated and the location of PWS was recorded. RESULTS: Two AAA expanded from 5cm to 5.5 cm in a period of 6 months after initial presentation, with increase of sac volume by 20% and 30%, respectively. The third AAA expanded to a diameter of 6.5 cm after a follow-up period of 13 months, with a subsequent increase in sac volume of 78%. The expansion of AAA max diameter did not correlate with differences in peak wall stress (PWS) values at the initial presentation, ranging from 20.5 to 21.3 Nt/cm2. CONCLUSION: PWS values cannot solely serve as a predictive tool for small AAA expansion. Small AAA expansion seem to be a multifactorial process, not solely described by PWS values but rather by a combination of mechanical, hemodynamic and biological factors.

External jugular vein aneurysm: a source of thrombotic complications.

Superficial venous aneurysms are rare and usually are uneventful. We present a case in which a 40-year old female presenting with a thrombosed external jugular vein aneurysm which previously caused an undetected pulmonary embolism. The aneurysm was excised and the external jugular vein was ligated under local anesthesia and anticoagulation was initiated. In conclusion aneurysms of the superficial venous system should be considered as a possible source of pulmonary emboli. These sites can safely be excised and ligated under local anesthesia offering long term protection from its possible complications.

The role of geometric parameters in the prediction of abdominal aortic aneurysm wall stress.

OBJECTIVE: To study the correlation between peak wall stress (PWS) and abdominal aorta aneurysm (AAA) geometric parameters in the presence of intraluminal thrombus (ILT). DESIGN: Computational study using finite element analysis. MATERIAL: AAA models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 19 patients. METHODS: PWS was evaluated in the presence and absence of ILT. DeltaPWS% represents the percentage change in PWS in the presence of ILT. The 3D lumen centrelines were extracted, and the values of torsion, tortuosity and mean curvature were estimated. RESULTS: A positive correlation was observed between DeltaPWS% and relative ILT volume (P=0.03). PWS in the presence of ILT significantly correlated only with the degree of centerline tortuosity (P=0.003) and maximum diameter (P<0.0001). The optimal predictive model for PWS in the presence of ILT was estimated to contain both maximum diameter and centreline tortuosity. CONCLUSIONS: Specific geometric parameters in AAA models in the presence of ILT could serve as potential predictors of elevated PWS. PWS correlated significantly with the maximum diameter and the degree of centreline tortuosity. Centreline tortuosity may become a useful addition to maximum diameter in the decision-making process of AAA treatment.

Peak wall stress does not necessarily predict the location of rupture in abdominal aortic aneurysms.

UNLABELLED: Using finite element analysis, we evaluated if the site of an aortic bleb, known to be prone to rupture, coincides with the location of peak wall stress (PWS) in a patient-specific abdominal aortic aneurysm (AAA) model. REPORT: PWS was not located at the bleb site, even when stress values were estimated for different bleb wall thicknesses (0.5-2.0 mm) while the rest of the AAA wall was considered constant (2 mm). DISCUSSION: The sites of PWS in AAAs should not always be considered as the sites most prone to rupture since other factors, such as wall strength, may play a role in rupture-risk prediction, depicting the need for further investigation of these parameters.

Combined simultaneous basilic and brachial vein transposition. A new technique to create an autologous vascular access.

In this report, we present a technique to extend the function of an antecubital arteriovenous fistula in which both the basilic and the brachial veins were simultaneously transposed to create an autologous graft in the arm. This procedure may particularly be applicable for patients in whom, although a brachio-cephalic fistula, anastomosing the brachial artery and the perforating antecubital vein, has been previously performed and has remained patent arterialising the deep arm veins, the cephalic vein has failed to mature or has been thrombosed after multiple punctures. Our preliminary experience in eight patients has shown satisfactory outcome.

Caval migration of a ureteral J-stent after simultaneous ureter and iliac vein perforation during its placement for obstructive pyelonephritis.

A variety of indications have made the use of double pigtail ureteral catheters routine in urological practice. Although side effects are frequent they are usually mild. We report a case of intravenous stent migration after simultaneous perforation of the left ureter and left common iliac vein during retrograde J-stent placement. To the authors' knowledge such a potentially severe complication of a J-stent has not been previously described. A postprocedural plain abdominal radiograph is a helpful tool which may suggest possible misplacement of the pigtail stent especially if urine fails to return from the distal opening and, if verified, advocate immediate intervention in order to avoid any further devastating complications.

The influence of intraluminal thrombus on abdominal aortic aneurysm wall stress.

AIM: The aim of this study was to examine the effect of intraluminal thrombus (ILT) on the peak wall stress (PWS) in abdominal aorta aneurysm models (AAA). METHODS: Anatomically correct patient specific AAA models were created by 3D reconstruction of in vivo acquired computed tomography images from 19 male patients. Patients were divided in two groups according to aneurysm peak transverse diameter, 5-7 cm (10 patients, ''intermediate'' group) and >7 cm (9 patients, ''large'' group), respectively. PWS was evaluated in the presence and absence of ILT. The percentage of PWS reduction (Delta PWS %) was estimated as a percentage of PWS value in the absence of ILT. Finite element analysis was used to numerically compute the wall stress distribution assuming a 2-mm thick hyperelastic AAA wall material model and a 120 mmHg systolic uniform wall loading. The thrombus was modeled as an isotropic, elastic, homogenous and incompressible material. The volume of ILT was estimated as a percentage of the AAA sac volume. RESULTS: The ILT volume was 49.9%+/-10.6% in the ''large'' group and 58.6%+/-13.2% in the ''intermediate'' group (t-test P=0.14). The ''large'' AAAs have higher PWS values than the ''intermediate'' group, both in the presence of ILT (36.9+/-5.8 vs. 23.5+/-6.2 Nt/cm(2), P=0.0001) as well as in the absence of ILT (52.6+/-15.4 vs. 35.0+/-10.5 Nt/cm(2), P=0.01). The presence of ILT resulted in a decrease of PWS (Delta PWS) in all cases. There was no statistical difference between the two groups in the mean PWS reduction, in the presence of ILT (26.9+/-12.5 Nt/cm(2) in the ''large'' group and 31.0+/-11.7 Nt/cm2 in the ''intermediate'' group, t-test P=0.48). However, a strong correlation between the ILT relative volume (ILT%) and the degree of PWS reduction was found only in the ''intermediate'' AAA group (Pearson correlation 0.86, P<0.001), whereas no correlation was observed in the ''large'' AAA group (Pearson correlation 0.05, P=0.9). CONCLUSIONS: The presence of ILT reduced the PWS in all cases. In the ''intermediate'' AAAs our results showed a linear correlation between ILT relative volume and cents PWS. However, in ''large'' aneurysms no such correlation was found. This indicates that the degree of ILT influence on the reduction of PWS in ''large'' AAAs may be related to other factors such as the geometric configurations of the AAA.