Nonempirical Free Volume Viscosity Model for Alkane Lubricants under Severe Pressures.

Viscosities η and diffusion coefficients D_{s} of linear and branched alkanes at pressure 0

Ultrasound-Assisted, Catheter-Directed Thrombolysis for Acute Intermediate/High-Risk Pulmonary Embolism: Design of the Multicenter USAT IH-PE Registry and Preliminary Results.

Catheter-based revascularization procedures were developed as an alternative to systemic thrombolysis for patients with intermediate-high- and high-risk pulmonary embolisms. USAT IH-PE is a retrospective and prospective multicenter registry of such patients treated with ultrasound-facilitated, catheter-directed thrombolysis, whose preliminary results are presented in this study. The primary endpoint was the incidence of pulmonary hypertension (PH) at follow-up. Secondary endpoints were short- and mid-term changes in the echocardiographic parameters of right ventricle (RV) function, in-hospital and all-cause mortality, and procedure-related bleeding events. Between March 2018 and July 2023, 102 patients were included. The majority were at intermediate-high-risk PE (86%), were mostly female (57%), and had a mean age of 63.7 ± 14.5 years, and 28.4% had active cancer. Echocardiographic follow-up was available for 70 patients, and in only one, the diagnosis of PH was confirmed by right heart catheterization, resulting in an incidence of 1.43% (CI 95%, 0.036-7.7). RV echocardiographic parameters improved both at 24 h and at follow-up. In-hospital mortality was 3.9% (CI 95%, 1.08-9.74), while all-cause mortality was 11% (CI 95%, 5.4-19.2). Only 12% had bleeding complications, of whom 4.9% were BARC ≥ 3. Preliminary results from the USAT IH-PE registry showed a low incidence of PH, improvement in RV function, and a safe profile.

[The Cannulation of the Arteriovenous Fistula in the Presence of a Stent: Precautions, Risks, and Possibilities].

A proper management and tailored interventions represented two fundamental steps to ensure a long-term use of the arteriovenous fistula (AVF). AVF failure can be attributed to various factors, with stenosis being the most common cause. Different techniques are employed for treating complications, but percutaneous endovascular procedures are the most widely used. In addition to angioplasty (PTA), the possibility of utilizing stents, particularly stent grafts (SG), has further improved outcomes. However, the insertion of these devices involves commitment to a segment of the vessel, which may vary in length, making the indication necessitate a careful evaluation. The positioning of a stent graft indeed limits the space for needle insertion, and on the other hand, the cannulation of the device is considered off-label according to technical specification. This work addresses the issue of puncturing these devices. Alongside a rapid overview, we describe a clinical case of continuous cannulation of a multiply stented AVF, for over 9 years, which opens up the discussion about the possibility of long-term cannulation through proper planning.

Toward a continuum description of lubrication in highly pressurized nanometer-wide constrictions: The importance of accurate slip laws.

The Reynolds lubrication equation (RLE) is widely used to design sliding contacts in mechanical machinery. While providing an excellent description of hydrodynamic lubrication, friction in boundary lubrication regions is usually considered by empirical laws, because continuum theories are expected to fail for lubricant film heights h0 ≪ 10 nm, especially in highly loaded tribosystems with normal pressures pn ≫ 0.1 GPa. Here, the performance of RLEs is validated by molecular dynamics simulations of pressurized (with pn = 0.2 to 1 GPa) hexadecane in a gold converging-diverging channel with minimum gap heights h0 = 1.4 to 9.7 nm. For pn ≤ 0.4 GPa and h0 ≥ 5 nm, agreement with the RLE requires accurate constitutive laws for pressure-dependent density and viscosity. An additional nonlinear wall slip law relating wall slip velocities to local shear stresses extends the RLE's validity to even the most severe loading condition pn = 1 GPa and h0 = 1.4 nm. Our results demonstrate an innovative route for continuum modeling of highly loaded tribological contacts under boundary lubrication.

Mechanical thrombectomy in acute limb ischemia: ad Interim results of the INDIAN UP Trial.

BACKGROUND: Penumbra/Indigo aspiration thrombectomy Systems (Penumbra Inc.) in patients with acute lower limb ischemia (ALLI) is becoming a fundamental alternative to surgical and intra-arterial thrombolysis. The INDIAN UP trial represents the second phase of the Italian national multicenter trial evaluating the safety and effectiveness of the device in the treatment of ALLI. METHODS: To assess vessel patency, the TIPI (Thrombo-aspiration In Peripheral Ischemia), is used. The TIPI flow in three different moments: at presentation, immediately after thromboaspiration, and after all adjuvant procedures. The primary outcome is the technical success of the thrombo-aspiration with the investigative system, defined as near complete or complete revascularization TIPI 2 - 3. Safety and clinical success rate were collected at one month follow-up. RESULTS: A total of 250 patients were enrolled. The mean age was 72.2±13.1 years and 72.1% were male. Rutherford grade on enrolment was I in 10.8%, IIa in 34.9%, and IIb in 54.4%. Primary technical success (TIPI 2-3 flow) was achieved in 90.8% of patients. Adjunctive procedures were needed in 158 cases. After all interventions, assisted primary technical success was 96.4%. No systemic bleeding complications or device related serious adverse events were reported. At one month follow up, survival rate was 97.2%, limb salvage was 97.6%. Primary patency was 89.6% and 13 (5.4%) reinterventions were registered. CONCLUSIONS: The updated results of the INDIAN UP trial have confirmed the high value of the mechanical thromboaspiration device Indigo Penumbra in the treatment of ALLI in a large variety of clinical and anatomical settings.

Report on an Italian survey of 72 stuck hemodialysis catheters.

BACKGROUND: Reports of stuck hemodialysis catheters have been on the rise in recent years. Aim of this work is to report how this complication has been managed and the relative outcomes in a multicente Italian survey. METHODS: Since 2012, the Italian Society of Nephrology (SIN) Project Group of Vascular Access has collected data among nephrologists on this complication. Data regarding 72 cases of stuck tunnelled central venous catheter (tCVC) in 72 patients were retrieved thanks to this survey. RESULTS: In 11 patients (15%) the stuck catheter was directly buried or left in place. Sixty-one cases were managed through advanced removal techniques. Among these, 47 (77%) stuck tunnelled central venous catheters were successfully removed, while 14 (23%) failed to be withdrawn. Considering removed tCVCs, the use of endoluminal balloon dilatation alone or in combination with other tools showed a percentage of success of 88%. The removal procedure involved numerous specialists. Some complications occurred, such as breakage of the line or bleeding, and two cases of haemopericardium during an advanced procedure. CONCLUSION: The survey shows how the stuck catheter complication was managed in different ways, with conflicting results. When utilized, endoluminal balloon dilatation proved to be the most effective and most often utilized technique, while some cases had suboptimal management or failure. This underlines how delicate the procedure is, and the need for both precise knowledge of this complication and timely organization of removal attempts.

Successful 8-year use of Venous Window Needle Guide for deep arteriovenous fistula cannulation.

We describe the case of a patient who had been on hemodialysis for 8 years using a native arteriovenous fistula cannulated through the Venous Window Needle Guide™ device (VWING). The overall outcome was excellent and complication-free with intact state of the underlying vessel and a high degree of patient satisfaction. The patient was able to carry out self-cannulation without any difficulty almost from the very beginning. The current unavailability of VWING is a missed opportunity in the field of vascular access.

[Percutaneous treatment of intermediate- and high-risk pulmonary embolism: two case reports]. / Trattamento percutaneo dell'embolia polmonare a rischio intermedio e ad alto rischio: due casi clinici.

Pulmonary embolism is the third most common cause of cardiovascular emergency. Risk stratification is crucial in the clinical and therapeutic management of these patients. The latest European guidelines introduced a new classification based on short-term mortality risk stratification, dividing patients into four categories (high, intermediate-high, intermediate-low and low risk). Despite the limited evidence in this field, the percutaneous treatment of pulmonary embolism represents an option of interest; however, correct patient selection and device choice should be better investigated. In this article, we present two case reports of patients with intermediate-high-risk and high-risk pulmonary embolism treated with the EkoSonic Endovascular System (EKOS Corp., Bothell, WA, USA) and the FlowTriever System (Inari Medical, Irvine, CA, USA), respectively.

Sex differences in outcome after thrombectomy for acute ischemic stroke. A propensity score-matched study.

Background and purpose: We sought to investigate whether there are gender differences in clinical outcome after stroke due to large vessel occlusion (LVO) after mechanical thrombectomy (EVT) in a large population of real-world patients. Methods: From the Italian Registry of Endovascular Thrombectomy, we extracted clinical and outcome data of patients treated for stroke due to large vessel occlusion. We compared clinical and safety outcomes in men and women who underwent EVT alone or in combination with intravenous thrombolysis (IVT) in the total population and in a Propensity Score matched set. Results: Among 3422 patients included in the study, 1801 (52.6%) were women. Despite older age at onset (mean 72.4 vs 68.7; p < 0.001), and higher rate of atrial fibrillation (41.7% vs 28.6%; p < 0.001), women had higher probability of 3-month functional independence (adjusted odds ratio-adjOR 1.19; 95% CI 1.02-1.38), of complete recanalization (adjOR 1.25; 95% CI 1.09-1.44) and lower probability of death (adjOR 0.75; 95% CI 0.62-0.90). After propensity-score matching, a well-balanced cohort comprising 1150 men and 1150 women was analyzed, confirming the same results regarding functional outcome (3-month functional independence: OR 1.25; 95% CI 1.04-1.51), and complete recanalization (OR 1.29; 95% CI 1.09-1.53). Conclusions: Subject to the limitations of a non-randomized comparison, women with stroke due to LVO treated with mechanical thrombectomy had a better chance to achieve complete recanalization, and 3-month functional independence than men. The results could be driven by women who underwent combined treatment.

Ultrasound in central venous access for hemodialysis.

Central venous cannulation is a frequent need for urgent or scheduled hemodialysis. Many studies confirmed the pivotal role of ultrasound in this procedure. Vascular access guidelines strongly recommend ultrasound guidance. Its usefulness has been demonstrated not only in reducing complications of venipuncture but more recently for the evaluation of central venous catheter (CVC) placement and real-time check for possible complications. The use of ultrasound requires a precise technique for the correct handling of the probe and the needle movement. Different approaches as the out-of-plane, in-plane, and oblique methods are available, enabling the most appropriate for the individual case. Although the learning curve for CVC ultrasound placement is usually fast, formal training and certification for beginners are strongly recommended.

Use of a 4 mm Amplatzer Vascular Plug II in the treatment of a renal arteriovenous fistula: a case report.

BACKGROUND: We report the use of a 4 mm vascular Amplatzer for the occlusion of a renal arterovenous fistula between the renal artery, at the hylum trifurcation point, and an aneurismatic vein draining into the main renal vein, where there was no possibility to use any other device from the venous side, because of the diameter and the high flow, neither from the arterious side without sacrificing lobar branches. The device was implanted at the exact point of communication, like a patent foramen ovale occluder, with the distal disc into the artery lumen and the other two proximal discs into the venous side. CASE PRESENTATION: A 34-years-old Caucasian woman suffered several episodes of paroxysmal supraventricular tachycardia associated with dyspnoea, after the onset of post-pregnancy hypertension. She underwent CTA, spectral Doppler sonography and angiography which showed a renal arteriovenous fistula (RAVF) between the renal artery, at the hylum trifurcation point, and an extremely ectatic vein draining into the main renal vein of the right kidney. With both arterial and venous access, the RAVF was selectively embolized using a 4 × 6 mm Amplatzer Vascular Plug II, released into the communication between artery and vein ensuring the patency of vessels involved. The RAVF was almost completely excluded and the hemodynamic effects associated were also corrected. CONCLUSIONS: The use of this device, though in an alternative way, allowed the exclusion of the high flow A-V fistula without sacrificing any parent renal vessel and preserving the renal function.

Shape memory polymer ovarian vein embolisation in a patient with nickel allergy.

BACKGROUND: Ovarian vein embolization in pelvic varicocele is usually obtained using nitinol coils. These devices can not be used in patients with proven nickel allergy. CASE PRESENTATION: Shape memory polymer is a new embolic material available to interventionalists. A patient presented with pelvic congestion syndrome requiring embolisation of the left ovarian vein. The target vessel consisted of two twisted branches, each 5-6 mm in diameter. The patient also had a known allergy to nickel. Considering the anatomy and allergy status, embolisation with polyurethane shape memory polymer vascular plugs was considered a good case strategy. The embolisation procedure was technically successful with the deployment of two shape memory polymer plugs into each of the two left ovarian vein branches. Follow-up magnetic resonance imaging at 4 months showed sustained occlusion of the treated vessels and the patient showed no signs of allergy to the implanted material. CONCLUSIONS: In conclusion, our case presented an opportunity to utilise a new embolic material and achieve a good outcome in a patient with an allergy that may have resulted in complications when using metallic implants.

Drug-coated balloon angioplasty in failing haemodialysis arteriovenous shunts: 12-month outcomes in 200 patients from the Aperto Italian registry.

BACKGROUND: We evaluated the safety and technical and clinical outcomes of angioplasty with a drug-coated balloon for the management of venous stenosis in arteriovenous grafts and arteriovenous fistulas in patients undergoing haemodialysis. METHODS: Data were obtained from an ongoing prospective, non-randomised registry conducted at three Italian centres. Patients were treated with a drug-coated balloon according to standard procedures in each participating centre. Evaluation was by colour Doppler imaging every 3 months. The primary end-point was primary assisted patency. The secondary end-point was the rate of assisted patency of the vascular access. RESULTS: A total of 311 angioplasty procedures in 200 patients, (60.4% male), were analysed. The procedural success rate was 100%. A total of 192 treatments of restenosis were necessary in 81 patients during average 21 ± 8 months follow-up. Kaplan-Meier estimates indicated that 88.0%, 64.2% and 40.6% of treated lesions were free from restenosis at 6, 12 and 24 months, respectively. Including multiple angioplasty, circuit patency rates were 99.2%, 92.5% and 84.8% at 6, 12 and 24 months, respectively. Primary patency rates were highest in shunts treated de novo with drug-coated balloons. Risk of restenosis was associated with circuit age (p = 0.017), history of treatment with conventional angioplasty (p < 0.001) and the kind of balloon used during pre-dilation (p = 0.001). CONCLUSION: The results suggest that favourable long-term patency rates can be achieved with the drug-coated balloon in a varied population of patients with failing haemodialysis arteriovenous shunts treated under conditions of actual care.

Venous Window Needle Guide for deep vessels and difficult arteriovenous fistula cannulation.

The Venous Window Needle Guide (VWING™) has recently been proposed for patients with difficult arteriovenous fistula (AVF) access for hemodialysis due to deep vessels or other cannulation-related problems. This totally subcutaneous titanium device is sutured onto the upper wall of the matured fistula and may facilitate cannulation by the button-hole technique. We describe our initial experience with nine implants in six patients with a cumulative follow-up of 83 months, and make some experience-based technical suggestions for implant and surveillance radiological imaging. The indication for implantation was deep vessel, previous failure of cannulation or unsuitable site for direct cannulation. No infectious complications were observed during follow-up and proper blood flow was constantly achieved. Some difficulties were occasionally encountered with regard to cannulation; nonetheless, patient satisfaction was not significantly affected. VWING seems to be an interesting option in some patients provided that surgical implantation is carefully carried out and preventive measures against infections are strictly observed.

Boundary lubrication of heterogeneous surfaces and the onset of cavitation in frictional contacts.

Surfaces can be slippery or sticky depending on surface chemistry and roughness. We demonstrate in atomistic simulations that regular and random slip patterns on a surface lead to pressure excursions within a lubricated contact that increase quadratically with decreasing contact separation. This is captured well by a simple hydrodynamic model including wall slip. We predict with this model that pressure changes for larger length scales and realistic frictional conditions can easily reach cavitation thresholds and significantly change the load-bearing capacity of a contact. Cavitation may therefore be the norm, not the exception, under boundary lubrication conditions.

A novel approach to inoperable or recurrent rectal cancer by chemoembolization: A new arrow in our quiver?

PURPOSE: Assess the feasibility, safety and efficacy of TACE with irinotecan loaded micro particles (debiri) for the treatment of locally advanced rectal cancer patients. RESULTS: We assessed the Edmonton Symptom Assessment System (ESAS). The tool is designed to assess nine common symptoms in cancer patients: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, wellbeing and shortness of breath. The ESAS score was 7 in 10/12 (83%) patients before treatment and 6 in 2/12 (16.5%) patients. After treatment in 6/12 (50%) patients the score dropped to 3; 3/12 (33%) reported 4, 1/12 (8%) reported 2. All patients experienced local control disease with a degree of citoreduction; in 4 cases (33%) we observed outstanding responses with a dramatic reduction in the tumors size which led us to surgical radical resections. MATERIALS AND METHODS: We run a prospective mono-institutional study where we recruited, 12 non- consecutive patients with histology confirmation of rectal cancer, inoperable and not treatable due to severe comorbidities, or pelvic recurrence/progression after curative treatment, chemotherapy, radiotherapy and/or surgery. Their performance status (PS) ECOG was 2-3 . Twelve patients (10 male and 2 female) with a median age 71 (range 56-89) were recruited in the study. CONCLUSIONS: The study has met the primary endpoint and showed encouraging activity. Debiri could be a possible option for locally advanced/inoperable or recurred rectal cancer patients. Further trials are warranted to validate this methodic in early stages.

A single-dose, randomized, cross-over, two-way, open-label study for comparing the absorption of boswellic acids and its lecithin formulation.

BACKGROUND: The oral administration of the gum resin extracts of Indian frankincense (Boswellia serrata Roxb. ex Colebr) results in very low plasma concentrations of boswellic acids (BAs), being far below the pharmacologically active concentrations required in vitro for anti-inflammatory activity. For that reason the use of Indian frankincense in clinical practice and pharmaceutical development has substantially lagged behind. Recently the application of new formulation technologies resulted in a formulation of frankincense extract with lecithin, which revealed improved absorption and tissue penetration of BAs in a rodent study, leading for the first time to plasma concentrations of BAs in the range of their anti-inflammatory activity. PURPOSE: In order to verify these encouraging results in humans, the absorption of a standardized Boswellia serrata extract (BE) and its lecithin formulation (CSP) was comparatively investigated in healthy volunteers. STUDY DESIGN: According to a randomized cross-over design with two treatments, two sequences and two periods, 12 volunteers alternatively received the lecithin-formulated Boswellia extract (CSP) or the non-formulated Boswellia extract (BE) at a dosage of 2×250mg capsules. METHODS: The plasma concentrations of the six major BAs (KBA, AKBA, ßBA, αBA, AßBA, AαBA) were determined using LC/MS. RESULTS: With the exception of KBA, a significantly higher (both in terms of weight-to-weight and molar comparison) and quicker absorption of BAs from the lecithin formulation was observed, leading to Cmax in the range required for the interaction with their molecular targets. CONCLUSION: These findings pave the way to further studies evaluating the clinical potential of BAs, and verify the beneficial effect of lecithin formulation to improve the absorption of poorly soluble phytochemicals.

Inferior mesenteric artery chemoembolization and chemotherapy for advanced rectal cancer: report of a clinical case.

Patients with advanced and incurable colorectal cancer have a very poor prognosis. Curative-intent resection was performed in 70%-90% of cases in reported series of colorectal cancer, sometimes after neoadjuvant chemotherapy and radiotherapy. The remaining 10%-30% of patients are treated with palliative intent, where treatment is aimed at relieving disease-related symptoms and improving quality of life. The provision of palliative care for these patients is complicated and outcomes are often disappointing. Although there are many available options including a variety of surgical and nonsurgical interventions, the best management remains controversial. Transarterial chemoembolization with irinotecan-loaded drug-eluting beads (DEBIRI) is an effective, minimally invasive procedure performed by interventional radiologists that allows intra-arterial drug delivery to stop vascular feeding and exert local cytotoxic effects. We here report on a patient treated with DEBIRI followed by systemic chemotherapy with the FOLFOX regimen for locally advanced, inoperable colorectal cancer.

Dealing with stuck hemodialysis catheter: state of the art and tips for the nephrologist.

The term stuck catheter refers to the condition in which a catheter is not removable from a central vein using standard techniques. Although it is a rare complication, in the last few years it has been reported ever more frequently in hemodialysis due to the widespread use of tunneled catheters. Poor knowledge of the correct procedures and limited experience and training of the specialist in facing this problem are the main reasons for catheter internalization. Stuck catheter is often diagnosed by the nephrologist, who should be competent enough to manage this clinical complication. Among the many options for removing a stuck catheter from the fibrin sleeve, an interventional radiology approach, mainly with endoluminal balloon dilatation, probably provides the best solution. Vascular surgery should be reserved to selected cases in which percutaneous techniques have failed. Nephrologists must play a central role in organizing the treatment of this complication with other specialists in order to avoid making mistakes that may preclude future positive results.