Computational fluid-structure interaction analysis of the end-to-side radio-cephalic arteriovenous fistula.

BACKGROUND AND OBJECTIVE: In the current work, we present a descriptive fluid-structure interaction computational study of the end-to-side radio-cephalic arteriovenous fistula. This allows us to account for the different thicknesses and elastic properties of the radial artery and cephalic vein. METHODS: The core of the work consists in simulating different arteriovenous fistula configurations obtained by virtually varying the anastomosis angle, i.e. the angle between the end of the cephalic vein and the side of the radial artery. Since the aim of the work is to understand the blood dynamics in the very first days after the surgical intervention, the radial artery is considered stiffer and thicker than the cephalic vein. RESULTS: Our results demonstrate that both the diameter of the cephalic vein and the anastomosis angle play a crucial role to obtain a blood dynamics without re-circulation regions that could prevent fistula failure. CONCLUSIONS: When an anastomosis angle close to the perpendicular direction with respect to the radial artery is combined with a large diameter of the cephalic vein, the recirculation regions and the low Wall Shear Stress (WSS) zones are reduced. Conversely, from a structural point of view, a low anastomosis angle with a large diameter of the cephalic vein reduces the mechanical stress acting on the vessel walls.

Impact of Multidisciplinary Team Meetings on Decision Making in Vascular Surgery: A Prospective Observational Study.

OBJECTIVE: This cohort study aimed to prospectively determine the impact of multidisciplinary team meetings (MDTs) on treatment plans in vascular patients. METHODS: The weekly MDT at the institution consisted of a structured discussion of vascular cases in the presence of at least one representative of each specialty from vascular surgery, angiology, and interventional radiology. Participants were asked to examine the cases entered on the digital MDT platform and to fill in forms with a detailed open text treatment recommendation for each patient. Individual recommendations were compared with the final MDT decision, which was based on a shared decision after discussion of clinical and radiological data. The primary endpoint was the agreement rate. The rate of decision implementation was determined to verify the adherence to MDT recommendations. RESULTS: Four hundred consecutive case discussions in 367 patients between November 2019 and March 2021 were included, excluding patients needing urgent treatment, yielding MDT discussion in 88.5% of carotid artery cases, 83% of aorto-iliac cases, and 51.7% of peripheral arterial cases, which included 56.9% of the chronic limb threatening ischaemia cases. The overall average agreement rate was 71% ± 41%. Analysis according to the specialty of the attending physician showed agreement rates of 82% ± 30% for senior vascular surgeons, 62% ± 44% for junior vascular surgeons, 71% ± 43% for interventional radiologists, 58% ± 50% for angiologists (p < .001), and 75% ± 38% considering only senior practitioners. The inter-rater agreement, resulted in kappa coefficients of 0.60 - 0.68 for senior vascular surgeons, 0.29 - 0.31 for junior vascular surgeons, 0.39 - 0.52 for interventional radiologists, and 0.25 for angiologists. The MDT treatment decision was implemented in 353 (96.2%) cases. CONCLUSION: The impact of MDT discussion on treatment recommendations and the adherence to MDT recommendations were significant and in line with results reported from other specialties.

[Risks and benefits of spirometry in preoperative assessment for the surgical repair of abdominal aortic aneurysm]. / Risques et bénéfices de la spirométrie avant réparation chirurgicale de l'anévrisme de l'aorte abdominale.

Since 2019, spirometry is no longer contraindicated in patients with an aneurysm of the abdominal aorta (AAA). Lung function testing has therefore become a tool for the preoperative morbidity and mortality assessment of patients eligible for surgical repair of AAA. European guidelines of anesthesiology, vascular surgery and pneumology, recommend preoperative spirometry for polymorbide patients, for whom the preoperative assessment must be as complete as possible in order to improve perioperative management and to help specialists decide of the operative mode: open (for patients with a low-risk profile) or endovascular (preferred in high-risk profile patients).

Depuis 2019, la spirométrie n'est plus contre-indiquée chez les personnes porteuses d'un anévrisme de l'aorte abdominale (AAA). Elle peut donc être considérée comme un outil supplémentaire dans le bilan préopératoire des patients candidats à une réparation chirurgicale de l'AAA. Les guidelines européennes de chirurgie vasculaire, de pneumologie et d'anesthésie la recommandent pour les patients polymorbides chez qui l'évaluation du risque péri-opératoire doit être la plus complète possible, afin d'améliorer la prise en charge péri-opératoire et d'aiguiller les spécialistes dans le choix de la technique d'intervention, à abdomen ouvert, pour les patients les plus sains et jeunes (à bas risque), ou par voie endovasculaire, préférée pour les patients âgés et/ou polymorbides (à haut risque).

SOFA Score as a Reliable Tool to Detect High Risk for Venous Thrombosis in Patients With Critical Stage SARS-CoV-2.

Background: Severe acute respiratory syndrome from coronavirus-2 (SARS-CoV-2) has been associated with an increased risk of venous thromboembolism (VTE). Different anticoagulation protocols have been applied in several studies in the absence of clear evidence. A reliable deep venous thrombosis (DVT) indicator in critical patients with SARS-CoV-2 could guide the anticoagulation treatment; however, it has not yet been identified, and clinical applicability of the most common markers is debatable. The aim of our study was to determine the actual incidence of DVT in critically ill SARS-CoV-2 patients and to find a reliable tool to identify patients who might benefit from therapeutic-intensity anticoagulation. Methods: From March 1, 2020 to May 31, 2020, all patients admitted to the intensive care unit (ICU) for SARS-CoV-2 at Ospedale Regionale di Locarno, Locarno, Switzerland, were prospectively enrolled and screened daily with ultrasound for DVT. Following international consensus, a higher-intensity thromboprophylaxis was administered to all patients who were not at increased risk for bleeding. Sepsis-induced coagulopathy (SIC) and sequential organ failure assessment (SOFA) scores were calculated and time-to-DVT event in a COX proportional-hazard regression model was performed. A receiver operating characteristic (ROC) curve was used to determine sensitivity and specificity and the Youden's Index to establish the best threshold. Results: A total of 96 patients were enrolled. Deep venous thrombosis was detected in 37% of patients. Sepsis-induced coagulopathy and SOFA scores were both correlated to DVT. A SIC score of 1 vs. ≥2 showed a close association with DVT, with sensitivity, specificity, and positive and negative predictive values of 90.0, 48.1, and 49.1, and 89.7%, respectively. Most significantly though, a SOFA score of 1 or 2 points was shown to be the most accurate value in predicting the absence of DVT, indicating no need for therapeutic-intensity anticoagulation. Its sensitivity, specificity, and positive and negative predictive values were 87.9, 100, and 100, and 93.7%, respectively. The D-dimer test showed lower sensitivity and specificity whereas platelet count and aPTT were not found to be correlated to DVT. Conclusions: Patients with SOFA scores of 1 or 2 are at low risk of developing DVT and do not require therapeutic-intensity anticoagulation. Conversely, patients with scores ≥3 are at high risk of developing DVT.

Computational Analysis of Turbulent Hemodynamics in Radiocephalic Arteriovenous Fistulas to Determine the Best Anastomotic Angles.

BACKGROUND: Hemodynamics has been known to play a major role in the development of intimal hyperplasia leading to arteriovenous fistula failure. The goal of our study is to investigate the influence of different angles of side-to-end radiocephalic anastomosis on the hemodynamic parameters that promote intimal dysfunction and therefore intimal hyperplasia. METHODS: Realistic three-dimensional meshes were reconstructed using ultrasound measurements from distal side-to-end radiocephalic fistulas. The velocity at the proximal and distal radial inflows and at specific locations along the anastomosis and cephalic vein was measured through duplex ultrasound performed by a single examiner. A computational parametric study, virtually changing the inner angle of anastomosis, was performed. For this purpose, we used advanced computational models that include suitable tools to capture the pulsatile and turbulent nature of the blood flow found in arteriovenous fistulas. The results were analyzed in terms of velocity fields, wall shear stress distribution, and oscillatory shear index. RESULTS: Results show that the regions with high oscillatory shear index, which are more prone to the development of hyperplasia, are greater and progressively shift toward the anastomosis area and the proximal vein segment with the decrease of the inner angle of anastomosis. These results are specific to distal radiocephalic fistulas because they are subject to proximal and distal radial inflow. CONCLUSIONS: The results of this study show that inner anastomosis angles approaching 60-70° seem to yield the best hemodynamic conditions for maturation and long-term patency of distal radiocephalic fistulas. Inner angles greater than 90°, representing the smooth loop technique, did not show a clear hemodynamic advantage.

Outcome of Tubular Aortoaortic Endografts in Infrarenal Aneurysmal Disease and Penetrating Abdominal Aortic Ulcers-a Long-Term Follow-up.

BACKGROUND: We describe the long-term follow-up of patients treated for infrarenal abdominal aortic aneurysms and penetrating ulcers by placement of tubular aortic endografts at our institution from 2010 to present. METHODS: This is a retrospective study using clinical data of patients treated from 2010 to present by placement of either a single aortic tubular endograft or by two overlapping endografts, using the "trombone technique." Aortic dimensions were measured from the preoperative computed tomography scans using three-dimensional reconstruction. The primary outcome was aortic reintervention. Secondary outcomes were aorta-related mortality, endoleaks, and postoperative complications. RESULTS: Twenty-eight patients were identified. Nine patients were treated for saccular aneurysms, and nineteen patients presented with penetrating aortic ulcers. The median follow-up was 31 months (range: 4-99). Twenty patients were treated with a single tubular device, while eight patients were treated using two overlapping devices. Aortic reintervention occurred in four patients (14.3%), all were treated initially with a single device. No aortic mortality occurred during follow-up. No aneurysm ruptures occurred. Four patients died during follow-up of unrelated causes. Endoleaks occurred in ten patients (35%). Five endoleaks were of type I (17.8%), of which three were of distal type (10.7%). Five endoleaks were of type II (17.8%). Shorter distal landing zones than 20 mm were present in two of the cases with a distal type I endoleak (P = 0.0232). Postoperative complications occurred in three (10.7%) patients including one myocardial infarction and two wound complications from a surgical cut down in the groin. CONCLUSIONS: The technique shows an acceptable postoperative complication rate but is characterized by high rate of occurrence of type I endoleaks and aortic reintervention in our series. Endovascular techniques using tubular endografts should be limited to cases with long proximal and distal sealing zones. The trombone technique seems preferable.

Assessing the Disturbed Flow and the Transition to Turbulence in the Arteriovenous Fistula.

The arteriovenous fistula (AVF) is the main form of vascular access for hemodialysis patients, but its maintenance is very challenging. Its failure is mainly related to intimal hyperplasia (IH), leading to stenosis. The aim of this work was twofold: (i) to perform a computational study for the comparison of the disturbed blood dynamics in different configurations of AVF and (ii) to assess the amount of transition to turbulence developed by the specific geometric configuration of AVF. For this aim, we reconstructed realistic three-dimensional (3D) geometries of two patients with a side-to-end AVF, performing a parametric study by changing the angle of incidence at the anastomosis. We solved the incompressible Navier-Stokes equations modeling the blood as an incompressible and Newtonian fluid. Large eddy simulations (LES) were considered to capture the transition to turbulence developed at the anastomosis. The values of prescribed boundary conditions are obtained from clinical echo-color Doppler (ECD) measurements. To assess the disturbed flow, we considered hemodynamic quantities such as the velocity field, the pressure distribution, and wall shear stresses (WSS) derived quantities, whereas to quantify the transition to turbulence, we computed the standard deviation of the velocity field among different heartbeats and the turbulent kinetic energy.

Clinical and surrogate endpoints in future studies on outcome of carotid revascularization.

This paper will provide a comparison of classical endpoints like stroke and mortality versus biochemical (non-STEMI) myocardial infarction and DW-MRI new brain lesions and will discuss the importance of cranial nerve lesion in CEA. An overview of possible endpoints of future randomized clinical trials will be given.

Debulking plus drug-coated balloon combination as revascularization strategy for complex femoropopliteal lesions.

This paper will discuss the results from the most recent randomized trials and large registries for DCB's and atherectomy, and the drawbacks of these two therapeutic options. It will also discuss the results of combination therapy in complex femoropopliteal lesions. Several studies indicate that combining atherectomy and DCB yields better outcomes in complex calcified lesions, but the only randomized pilot study could not demonstrate a benefit of combination therapy in the mid-term follow-up. Larger, randomized studies are needed to define the role of atherectomy followed by DCB angioplasty further.

Ultrasound screening for abdominal aortic aneurysms.

QUESTIONS UNDER STUDY: This pilot study aimed to assess the feasibility, acceptance and costs of an ultrasound scan screening programme for abdominal aortic aneurysms (AAA) in the elderly male population resident in Canton Ticino, Switzerland. METHODS: The target population were male patients aged 65-80 years who attended the outpatient clinics of the Lugano Regional Hospital in 2013. The patients showing interest were contacted by phone to verify their eligibility and fix the appointment for the ultrasound scan of the abdominal aorta. Patients with recent examinations suitable for AAA detection were excluded. Aneurysm was defined as an abdominal aorta with sagittal and/or axial diameter  30 mm. Patients' characteristics and study results were presented as descriptive statistics. The chi-squared test was used to compare categorical variables with p <0.05 as a statistical significance threshold. RESULTS: 1634 patients received the screening information leaflet and 745 (45.6%) underwent the ultrasound scan. Among the 1091 eligible patients, the acceptance rate was 68.3%. A previously unknown AAA was diagnosed in 31 patients (4.2%, 95% confidence interval 2.8-5.9%). Age and area of residence had a statistically significant impact on patient's acceptance rate (p <0.05). The mean cost per screened patient was CHF 88. CONCLUSIONS: AAA screening of male patients aged 65-80 years is feasible with limited financial and organisational effort. Adherence might be improved by a larger community-based programme and involvement of general practitioners.

Successful Endovascular Repair of a Penetrating Aortic Ulcer in Bacterial Aortitis.

Infective aortitis (IA) and penetrating aortic ulcer (PAU) impending for rupture represent 2 hostile life-threatening conditions. Simultaneous presentations of these rare entities can be considered an exception. The pleomorphic clinical presentation and the multifactorial etiology require a multidisciplinary approach to reach a correct diagnosis and an urgent treatment. We report the case of a 65-year-old patient presented with acute abdominal pain and septic shock secondary to a bacterial aortitis and penetrating ulcer of abdominal aorta. Unfit for surgery due to severe comorbidities, he was treated by means of a tubular endograft and long-term antibiotic therapy. A rapid improvement of clinical conditions was observed during the subsequent hospital stay. Complete regression of aortic involvement was demonstrated after 1 year. In conclusion, for selected patients affected by IA and PAU an endovascular approach associated to long-term antibiotic therapy may be safe and effective.

Anastomotic false aneurysm of the aorta: closure with a "sandwiched" coil.

PURPOSE: To describe the treatment of a noninfected saccular anastomotic false aneurysm (AFA) of the abdominal aorta with the use of a single "sandwiched" coil. CASE REPORT: A 65-year-old man presented with a saccular AFA of the distal anastomosis exactly at the level of the aortic bifurcation 1 month after open abdominal aortic aneurysm repair. Endograft exclusion was not attempted because an aortouni-iliac configuration would have sacrificed a patent iliac axis. Coil embolization was the preferred strategy. Use of 3-dimensional rotational angiography and 3-dimensional roadmap was necessary to cannulate the neck of the AFA. Complete thrombosis and shrinkage of the sac was achieved by "sandwich coiling" of the neck after deployment of a single pushable hydrogel-coated coil. Imaging at 9 months postprocedure showed no sign of the aneurysm sac. CONCLUSION: This novel technique can be used for selected saccular AFAs with a narrow neck. In such cases, sandwich coiling may avoid sacrifice of a patent iliac axis.

In-stent restenosis: mid-term results of debulking using excimer laser and drug-eluting balloons: sustained benefit?

BACKGROUND: In-stent restenosis (ISR) after endovascular treatment of stenotic and occlusive disease of the infrainguinal arteries is still a clinical challenge. The purpose of this study is to evaluate the mid-term follow-up of a combination therapy using laser debulking and drug-eluting balloons for ISR. METHODS: A prospective cohort of 14 patients (10 female, 4 male) with clinically relevant (Rutherford 3-6) ISR who were treated with excimer-laser angioplasty and drug-eluting balloons and a clinical follow-up of at least 9 months was evaluated. RESULTS: Mean age was 78 ± 6.5 years (range, 67-88 years). The mean lesion length treated was 133.2 ± 107.2 mm (range, 10-380 mm). The mean time to occurrence of restenosis after initial treatment was 8.6 ± 4.7 months (range, 2-18 months). Technical success was 100%. Distal embolization occurred in 2 cases, and was treated successfully by endovascular means. No other periprocedural major adverse events occurred. All patients were available for clinical follow-up and 12 patients were available with Duplex follow-up. At a mean clinical follow-up of 19.1 ± 8.7 months (range, 9-38 months), 1 target lesion revascularization was seen (at 3 years after the ISR treatment). In the patients with critical limb ischemia (n = 7), no major amputations were needed. Twelve patients had Duplex control (mean follow-up, 19.4 ± 9.4 months; range, 9-38 months). Binary restenosis (>50%) was seen in 1 case at 36 months; it was the same patient who had TLR. A 25%-50% stenosis was seen in 4 patients (mean follow-up, 25 months; range, 19-38 months). No sign of neointimal hyperplasia was demonstrated in 7 patients (mean follow-up, 14.3 months; range, 9-19 months). CONCLUSION: These mid- to long-term data compare favorably with results obtained with standard balloon angioplasty, cutting-balloon angioplasty, and balloon angioplasty using drug-eluting balloon. Longer follow-up and randomized trials are necessary to further define the role of combined excimer-laser debulking and drug-eluting balloon angioplasty in the treatment of ISR.

A huge mucinous cystadenoma of ovarian: a rare case report and review of the literature.

We report a case of a 63-years-old woman with a ten years history of increasing abdominal girth with associated abdominal pain. Abdomino-pelvic ultrasound and computed tomography scan revealed a large left ovarian cyst. The patient underwent laparotomy, resection of ovarian cyst and hysterectomy with bilateral ovarian resection. The removed huge mucinous cystadenoma, weighed 27 kg. Her post-operative course was unremarkable.

The challenge of posttraumatic thrombus embolization from abdominal aortic aneurysm causing acute limb ischemia.

We report the first documented case of distal thromboembolism originating from an abdominal aortic aneurysm (AAA) after a blunt trauma. A 72-year-old man with a known 6.2 cm AAA was brought to our emergency department with signs of bilateral acute limb ischemia developing immediately after an accidental fall. The occlusion was confirmed at computed tomographic angiography, and the aneurysm showed a fragmentated/ulcerated mural thrombus, morphologically different as compared to the previous computed tomography (CT). A thromboembolectomy was performed and, after treatment of the ischemic complications, the aneurysm was repaired by open surgery. Embolization from aneurysms in the setting of a trauma is a challenge for the vascular surgeon, also because of its rare occurrence. We describe the management and discuss the operative strategy we opted for in this patient.