Small Diameter Catheters Research Articles

Rate and risk factors of tip displacement of umbilical venous catheterization at different indwelling time points in preterm infants

Objectives: To investigate the rate and risk factors of tip displacement of umbilical venous catheterization (UVC) in preterm infants. Methods: This was a multicenter cohort study. Study population were preterm infants admitted to 44 tertiary hospitals in China between October 2019 and August 2021. Demographic information, general clinical data, UVC indwelling conditions and related complications were collected. The primary outcome was the rate of UVC tip displacement. The observation time points were 2 d and 7 d after UVC. They were grouped according to UVC displacement, gestational age, and birth weight. Binary Logistic regression was used to analyze the risk factors of UVC tip displacement. Results: The 2 086 preterm infants had a gestational age of (29.9±2.3) weeks and a birth weight of (1 248±298) g. There were 1 106 male preterm infants (53.0%). The rate of UVC displacement at 2 d and 7 d were 34.6% (721/2 086) and 33.6% (494/1 470), respectively, with no statistically significant difference (χ2=0.35, P=0.533). Univariate analysis indicated that male infants, small gestational age, low birth weight and small catheter diameter were all risk factors for UVC tip displacement at the 2 d time point (all P<0.05). Multivariate analysis showed that small catheter diameter was an independent risk factor for tip displacement at both 2 d (OR=0.47, 95%CI 0.34-0.66) and 7 d (OR=0.39, 95%CI 0.25-0.59) time points (both P<0.001). Conclusions: The rate of UVC tip displacement is high in preterm infants. It should be avoided to deliberately select a small diameter catheter for UVC, and pay attention to the imaging monitoring of the tip position after UVC.

Embosphere Size Selection and Dilution Rate in Preoperative Tumor Embolization of the External Carotid Artery System Using a Small-diameter Catheter.

The widespread adoption of preoperative embolization in highly vascularized brain tumors often involves the frequent use of Embosphere (Merit Medical Systems, South Jordan, Utah, USA). Nevertheless, inconsistency in size selection and dilution rates across different institutions requires comprehensive examination. This study explored the appropriate size and dilution rate of Embosphere microspheres. To assess catheter occlusion and Embosphere breakage, various dilutions (4-, 10-, 20-, 30-, and 60-fold) of Embosphere 300-500 and 500-700 μm were injected into the catheter in vitro. Results indicated that 20-fold or higher dilutions of Embosphere 300-500 μm and 30-fold or higher dilutions of Embosphere 500-700 μm showed no occlusion of the Excelsior SL-10 microcatheter (Stryker, Fremont, CA, USA) or Embosphere breakage. For embolization, to reduce the risk of Excelsior SL-10 occlusion further, a 30-fold dilution of Embosphere 300-500 μm and a 60-fold dilution of Embosphere 500-700 μm were employed. For 195 blood vessels in 107 patients (84 with meningioma and 23 with schwannoma), embolization was carried out using a 30-fold dilution of Embosphere 300-500 μm when the provocative test was negative and a 60-fold dilution of Embosphere 500-700 μm when the test was positive or when there was a risk of migration into neurotrophic vessels. Contrast-enhanced magnetic resonance imaging after embolization revealed a reduced enhancement effect in 69.1% of cases. Embolization using a 30-fold dilution of Embosphere 300-500 μm and a 60-fold dilution of Embosphere 500-700 μm with an Excelsior SL-10 catheter is safe and satisfactory, which minimizes microcatheter occlusion.

Artificial Pneumothorax Using the Liver-Directed Approach and Seldinger's Technique: Technical Feasibility and Safety.

Purpose This study aimed to evaluate the technical feasibility and safety of artificial pneumothorax induction for percutaneous procedures using the liver-directed approach and Seldinger's technique. Materials and methods The data of 25 consecutive patients who underwent percutaneous procedures after inducing artificial pneumothorax were reviewed retrospectively. The liver surface was punctured with an 18-gauge indwelling needle via the intercostal space in the inferior thoracic cavity under ultrasound guidance, avoiding the lung parenchyma and leaving the catheter in place. After a deep inhalation pulled the catheter tip into the pleural cavity, a hydrophilic guidewire was inserted through the catheter. Finally, a small-diameter catheter was inserted into the pleural cavity over the guidewire to induce artificial pneumothorax. Procedure time (the time from local anesthesia to completion of the procedure), technical success (successful induction of artificial pneumothorax), clinical success (successful completion of the percutaneous procedure), and complications (categorized according to the Clavien-Dindo classification) were evaluated in this study. Results The artificial pneumothorax induction was successful in all cases. Clinical success was achieved in 23 of 25 procedures (92%). No severe complications were observed. Conclusion The liver-directed approach and Seldinger's technique for inducing artificial pneumothorax was safe and feasible for avoiding lung injury.

Endoscopic Ultrasound-Guided Hepaticogastrostomy with Antegrade Stenting Without Dilation Device Application for Malignant Distal Biliary Obstruction in Pancreatic Cancer.

Endoscopic ultrasound-guided hepaticogastrostomy with antegrade stenting (EUS-HGAS) is a promising therapeutic option for malignant distal biliary obstruction (MDBO) in the event of transpapillary approach failure. Eliminating the fistula dilation step may further decrease the incidence of adverse events (AE) and simplify the procedure. This study focused on MDBO associated with pancreatic cancer and aimed to examine the utility of EUS-HGAS without the use of any dilation devices. This retrospective study investigated consecutive patients in whom the transpapillary approach had failed or was difficult, and who underwent EUS-HGAS without dilation device usage, using a tapered small-diameter catheter, ultrathin delivery system, and tapered dedicated plastic stent. The outcomes of this study included the technical success, clinical success, AE incidence, and recurrent biliary obstruction (RBO) associated with the procedure. During the study period, EUS-HGAS without dilation device usage was attempted for 57 patients with MDBO due to pancreatic cancer. The technical and clinical success rates were 91.2% (52/57) each. The median procedural time was 25min. The rates of early and late AE besides RBO were 3.5% (2/57) and 1.9% (1/52), respectively. The incidence rate of RBO was 30.8% (16/52), and the median time to RBO was 245days. The rate of successful endoscopic reintervention for RBO via the fistula was 100% (16/16). EUS-HGAS without the use of dilation devices showed good technical feasibility with a low AE rate. It may be a useful option for MDBO associated with pancreatic cancer when the transpapillary approach is difficult.

A pilot study of evaluation of semi-rigid and flexible catheters for less invasive surfactant administration in preterm infants with respiratory distress syndrome—a randomized controlled trial

BackgroundIn respiratory distress syndrome, many neonatology centers worldwide perform minimal invasive surfactant application in premature infants, using small-diameter catheters for endotracheal intubation and surfactant administration.MethodsIn this single-center, open-label, randomized-controlled trial, preterm infants requiring surfactant administration after birth, using a standardized minimal invasive protocol, were randomized to two different modes of endotracheal catheterization: Flexible charrière-4 feeding tube inserted using Magill forceps (group 1) and semi-rigid catheter (group 2). Primary outcome was duration of laryngoscopy. Secondary outcomes were complication rate (intraventricular hemorrhage, soft-tissue damage in first week of life) and vital parameters during laryngoscopy. Between 2019 and 2020, 31 infants were included in the study. Prior to in-vivo testing, laryngoscopy durations were studied on a neonatal airway mannequin in students, nurses and doctors.ResultsMean gestational age and birth weight were 27 + 6/7 weeks and 1009 g; and 28 + 0/7 weeks and 1127 g for group 1 and 2, respectively. Length of laryngoscopy was similar in both groups (61.1 s and 64.9 s) overall (p.77) and adjusted for weight (p.70) or gestational age (p.95). Laryngoscopy failed seven times in group 1 (43.8%) and four times (26.7%) in group 2 (p.46). Longer laryngoscopy was associated with lower oxygen saturation with lowest levels occurring after failed laryngoscopy attempts. Secondary outcomes were similar in both groups. In vitro data on 40 students, 40 nurses and 12 neonatologists showed significant faster laryngoscopy in students and nurses group 2 (p < .0001) unlike in neonatologists (p.13).ConclusionThis study showed no difference in laryngoscopy duration in endotracheal catheterization when comparing semi-rigid and flexible catheters for minimal invasive surfactant application in preterm infants. In accordance with preliminary data and in contrast to published in-vitro trials, experienced neonatologists were able to perform endotracheal catheterization using both semi-rigid and flexible catheters at similar rates and ease, in vitro and in vivo.Trial registrationClinicalTrials.gov. NCT05024435 Registered 27 August 2021—Retrospectively registered.

Optical coherence tomography.

Optical coherence tomography (OCT) is a non-contact method for imaging the topological and internal microstructure of samples in three dimensions. OCT can be configured as a conventional microscope, as an ophthalmic scanner, or using endoscopes and small diameter catheters for accessing internal biological organs. In this Primer, we describe the principles underpinning the different instrument configurations that are tailored to distinct imaging applications and explain the origin of signal, based on light scattering and propagation. Although OCT has been used for imaging inanimate objects, we focus our discussion on biological and medical imaging. We examine the signal processing methods and algorithms that make OCT exquisitely sensitive to reflections as weak as just a few photons and that reveal functional information in addition to structure. Image processing, display and interpretation, which are all critical for effective biomedical imaging, are discussed in the context of specific applications. Finally, we consider image artifacts and limitations that commonly arise and reflect on future advances and opportunities.

Convection-Enhanced Delivery of Alkaloid - Loaded Maghemite Nanoparticles against 9L - Gliomass Cell Line

Convection Enhanced Delivery (CED) is a novel approach to synthesize and facilitate targeted delivery of phytocontituents/ pharmaceuticals to the brain. The CED procedure involves a minimally invasive surgical exposure of the brain, followed by placement of small diameter catheters directly into the brain tumor. The study was designed to synthesize unique, sustained release, targeted delivery with no toxicity of piperidine alkaloids along with maghemite (γ-Fe2O3), poly-ethylene glycol and human serum albumin conjugation using 9L-gliomass cell line. Subsequently different nanoparticles (NPs) were prepared Naked NPs and HSA- or polyethylene glycol (PEG)-coated NPs with/without piperidine alkaloid were studied. In vitro results showed no toxicity and a similar cell-kill efficacy of the piperidine alkaloid-loaded particles via HSA coating to that of free piperidine alkaloid, while piperidine alkaloid-loaded particles via PEG coating showed low efficacy

Swellable catheters based on a dynamic expanding inner diameter

Intravenous (IV) fluid administration is critical for all patients undergoing care in a hospital setting. In-patient hospital practice, surgeries, and emergency care require functional IVs for fluid replacement and medication administration. Proper placement of IVs is vital to providing medical services. The ease of placement of an IV catheter, however, depends not only on the size of the catheter but also on provider experience and patient demographics such as age, body mass index, hydration status, and medical comorbidities present challenges to successful IV placement. Smaller diameter IV placement can improve success and there are instances where multiple small diameter catheters are placed for patient care when larger bore access is unattainable. Smaller inner-diameter catheters for anesthesia have functional constraints. Ideally, there would be a smaller catheter for placement that could function as a larger catheter for patient care. One solution is the idea of functionally responsive catheters. Here, we evaluated tubular-shaped hydrogels as potential functional catheters that can increase in inner diameter through fluid swelling using cross-linked homopolymers of polyacrylamide, PAM (10–40% w/w), and their copolymers with 0–8% w/w Poly-(Ethylene Glycol)-Diacrylate, PEGDA. For the PAM gels, the water transport mechanism was shown to be concentration-dependent Fickian diffusion, with the less concentrated gels exhibiting increasingly anomalous modes. Increasing the PEGDA content in the network yielded an initial high rate of water uptake, characterized by Case II transport. The swelling kinetics depended strongly on the sample geometry and boundary conditions. Initially, in a submerged swelling, the annulus expands symmetrically in both outward and inward directions (it thickens), reducing the internal diameter by up to 70%. After 1 h, however, the inner diameter increases steadily so that at equilibrium, there is a net (>100%) increase in all the dimensions of the tube. The amount of linear swelling at equilibrium depended only on the polymer volume fraction as made, while the rate of inner diameter expansion depended on the hydrophilicity of the matrix and the kinetics of sorption. This study serves as proof of concept to identify key parameters for the successful design of hydrogel-based catheter devices with expanding inner-diameters for applications in medical care.

Drenaje percutáneo con catéter del neumotórax en pacientes con COVID–19

Introducción: La transmisión del SARS-CoV-2 principalmente se da por gotas y contacto cercano con las personas infectadas, pero los aerosoles parecen ser también una fuente de infección. El neumotórax espontáneo o secundario puede presentarse en pacientes con COVID-19, ayudado por patologías de base como la enfermedad pulmonar obstructiva crónica. Es necesario garantizar procedimientos seguros para los pacientes y buscar todas las medidas posibles para la protección del personal de la salud, por eso el drenaje de neumotórax con catéter pleural en lugar de sonda de toracostomía puede ser una de ellas.&#x0D; El objetivo de este estudio es presentar a los cirujanos una alternativa a la toracostomía tradicional, mediante la utilización de catéteres de menor diámetro, para la resolución de la ocupación pleural.&#x0D; Aspectos Técnicos: Se presenta el protocolo para inserción segura de un catéter pleural para el drenaje de neumotórax, mediante un sistema completamente cerrado, y se dan recomendaciones sobre el uso de filtros virales y solución viricida en el sistema de drenaje pleural conectado al catéter.&#x0D; Conclusión: El estado de pandemia por COVID-19 y el riesgo que representa para los profesionales de la salud la exposición a fuentes de transmisión durante procedimientos generadores de aerosoles, hace que se deban extremar las medidas para evitar el contagio.

SCIDOT-48. EVALUATING THE THERAPEUTIC EFFICACY AND CONVECTION ENHANCED DELIVERY (CED) TOXICITY ANALYSIS OF CDK4/6 INHIBITOR PALBOCICLIB FOR DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)

Abstract DIPG is a devastating, aggressive brain tumor of childhood. No chemotherapeutic agent has so far shown significant clinical efficacy and focal radiation therapy provides only temporary relief. Recent studies on the genomic aberrations of pediatric gliomas have shown that a subset of these tumors harbor focal gains in proteins of the cyclin-dependent kinase (CDK) 4/6 cell cycle pathway. H3.3K27M mutation, associated with &gt;80% of DIPGs, has also been associated with epigenetic silencing of p16 tumor suppressor, an important effector in regulating CDK4/6 pathway. In this study, we characterized and confirmed through immunoblot analysis that proteins involved in CDK 4/6 pathway, including Rb1, are intact in multiple patient derived DIPG (SU-DIPG-IV, SU-DIPG-XIII, SU-DIPG-XVIII, SF8628) and wild type (SF9428) cell lines. Expression of p16 was decreased or undetectable in DIPG cells compared to normal astrocytes. In addition, pharmacologic inhibition of CDK4/6 with palbociclib showed dose dependent reduction in DIPG cell proliferation with IC50 ranging from 5.42uM to 21.35uM between different cell lines. However, major problems of palbociclib are that it does not readily cross the blood-brain-barrier (BBB) and has major systematic toxicities, such as myelosuppression, which limits oral dosing. One solution to overcome the BBB is convection enhanced delivery (CED) which is a form of local delivery that bypasses the BBB by placement of small diameter catheters directly into the brain tumor. With this approach, high regional drug concentration can be achieved with negligible systemic toxicity. In this study, we also observed no significant short- or long-term neurotoxicity of palbociclib delivered via CED in a mouse model. We hypothesize that the CDK4/6 cell cycle pathway has an important role in DIPG tumorigenesis and progression and that existing therapies targeting these pathways, which are already in clinical use for other cancers, can be rapidly repurposed for the treatment of DIPG through CED.

Percutaneous Inserted Venous Catheter via Femoral Vein in Extremely Low-Birth-Weight Infants: A Single-Center Experience.

This study aimed to assess the applicability of the insertion of small diameter catheters through the femoral vein in extremely low-birth-weight (ELBW) infants. All femoral small diameter catheters (Silastic or femoral arterial catheter [FAC]) inserted in ELBW infants in a tertiary level neonatal intensive care unit were retrospectively reviewed. Success rate, dwelling time, and percutaneously inserted central venous catheter-related complications were recorded. Thirteen small diameter catheters were inserted in seven ELBW infants. Mean gestational age at birth was 25+3 weeks (standard deviation [SD] ± 2.12) and mean birth weight was 686 g (SD ± 204.9). Mean weight at the first time of insertion was 1,044 g (SD ± 376.3). In two occasions, a FAC was used instead of a Silastic. In most cases (11/13, 84.6%), the patient was intubated prior to the procedure. The mean dwelling time was 16.7 days (SD ± 9.8). Most of the inserted small diameter catheters were removed electively (8/12, 66.7%), except for one episode of clinical sepsis from coagulase-negative Staphylococcus and three cases of accidental line extravasation. No other complications were reported. The success rate was 92.3%. Femoral venous catheterization using small diameter catheters in ELBW infants may be promising when other routes have been exhausted. Our results support that it is a feasible technique that can be performed at the bedside with successful results when conducted by experienced personnel.

Incidental angiographic finding of extended chronic brachial artery occlusion: an uncommon but unavoidable cause of transradial catheterisation failure.

The recent widespread adoption of radial access in performing percutaneous coronary interventions has determined a greater reduction of vascular complications and related bleedings than traditional femoral access, even leading to favourable impact on clinical outcome through a significant reduction of combined efficacy and safety clinical end-point in a recent large randomised trial (1). Besides, the progressive diffusion of slender radial approach with dedicated vascular sheaths and small diameter catheters have almost always allowed to accomplish coronary procedures even in case of adults with small radial artery, such in elders, in females or in subjects of small body surface, particularly prevalent in some racial population (South-East Asians). However, in rare cases, anatomical variants of radial calibre and course and anomalies of brachio-cephalic trunk are responsible of failure of radial access or may determine difficult catheter manipulation even inducing to abandon vascular access.

Pentaxial access platform for ultra-distal intracranial delivery of a large-bore hyperflexible DIC (distal intracranial catheter): A technical note

Abstract Background Intracranial access techniques in modern neurointervention are shifting towards more robust access platforms. We present in this report a novel method of navigating a 5 French distal intracranial catheter (DIC) deep within the intracranial circulation in an atraumatic fashion via a pentaxial access system. Methods We retrospectively reviewed all neurointerventions performed at two author institutions identifying all aneurysm treatments where the pentaxial system was used to build the catheter support for intracranial positioning of a 5 French DIC. Procedural data collected include parent artery tortuosity, use of vasodilator, intra-procedural DIC position, and peri-procedural complications. Results The pentaxial access platform provided ultra-distal intracranial navigation of the 5 French DIC in the following 11 neurointerventions for treatment of anterior circulation aneurysms: Pipeline embolization device (PED) for anterior communicating artery (ACom) aneurysm, n = 2; surpass for large internal carotid artery (ICA) aneurysm, n = 4; Woven EndoBridge (WEB) device for ACom aneurysm, n = 5. Mean patient age was 55 ± 11 years (range 40–75 years). Mean aneurysm size was 6.7 mm ± 3.8 mm (range 2–16 mm). Mean fluoroscopy time was 29 ± 16.7 min. Intra-procedural DIC positions achieved included supraclinoid ICA (n = 6), M1 (n = 4), and A1 (n = 1). No significant catheter-related complications occurred. Conclusion Distal intracranial catheters can achieve ultra-distal intracranial positions safely with the pentaxial access platform. This technique is a near no step-off, atraumatic method of navigating a DIC in a stepwise fashion over de-escalating smaller diameter catheters via a microwire. Familiarity with catheter specifications including diameters and length is essential for the success of this system.

Optimization of injectable scaffolds with enhanced mechanical properties for cell therapy and tissue engineering

Event Abstract Back to Event Optimization of injectable scaffolds with enhanced mechanical properties for cell therapy and tissue engineering Caroline Ceccaldi1, 2, Sepideh Samei1, 2, Yasaman Alinejad1, 2, Medeine Bucionyte2, Marta Cerruti3 and Sophie Lerouge1, 2 1 Ecole de technologie supérieure (ETS), Department of Mechanical Engineering, Canada 2 Centre de recherche du CHUM (CRCHUM), Laboratoire de biomatériaux endovasculaires (LBeV), Canada 3 McGill University, Materials Engineering, Canada Introduction: Injectable hydrogels present high potential for cell therapy and tissue engineering because they can ensure appropriate localization, retention and survival of seeded cells. They should also provide them with a mechanically resistant support despite injection through catheters and needles to minimize surgical incision. In this project we discovered and optimized thermosensitive chitosan hydrogels with enhanced mechanical properties and biocompatibility for cell therapy applications. Materials and Methods: Chitosan (CH) acidic solution was combined with a mix of sodium hydrogen carbonate (SHC) and phosphate buffer (PB) or beta-glycerophosphate (BGP) and compared to conventional CH-BGP gels[1]. The effect of formulation on rheological properties, injectability, macroporosity and mechanical strength were evaluated by rheometry (Physica MCR301), SEM, compression and tensile tests (Bose Electroforce).To assess potential for cell encapsulation, pH and osmolality were measured and survival and growth of encapsulated fibroblasts and mesenchymal stem cells were evaluated over 7 days by alamar-blue and Live/Dead. Hydrogels were injected subcutaneously in rats. Finally, the best formulations were further optimized using chondroitin sulfate and addition of catechol groups[2] to improve cell growth and tissue adhesion respectively. Results and Discussion: Mechanical characterization in tension and compression were drastically enhanced compared to conventional CH-BGP hydrogels, highest properties being observed for SHC at 0.075M and slightly decreasing as a function of PB concentration. Secant Young modulus at 50% rose from 6±1 for CH-BGP0.4M up to 158±11 kPa (25 fold increase) and the ultimate strength from 13 to 143 kPa (10 fold increase). Hydrogels presented clear thermosensitive properties (Fig.1a) with relatively stable complex viscosity at room temperature and drastic increase of the storage modulus (G’) around 35°C. This ensures easy and homogenous encapsulation of cells and drugs, injectability though small-diameter catheter and needles (Fig.1b), but rapid formation of a cohesive and load-bearing structure after injection in vivo. Cell survival was excellent thanks to isoomolality and macroporosity of the scaffold (Fig. 2). CS was found to further increase cell growth, while the effect of chitosan modification with catechol groups on tissue adhesion is under evaluation. Conclusion: These new injectable scaffolds present excellent mechanical properties and can be fine-tuned depending on the targeted application. They hold great promise for cell therapy and tissue engineering.

Optimization and characterization of injectable chitosan-iodixanol-based hydrogels for the embolization of blood vessels.

Chitosan-thermosensitive hydrogels present interesting features for the embolization of blood vessels, but need to be better characterized and optimized. Chitosan polymer (degree of deacetylation (DDA) of 94%) was purified and combined with Visipaque (VIS), a nonionic isotonic contrast agent composed of iodixanol. A beta-glycerolphosphate (βGP) solution was then added to induce gelation at body temperature. The gelation process was monitored by rheometry, measuring the evolution of the sample storage (G') and loss (G″) moduli as a function of VIS and βGP concentration. Adding VIS significantly slowed down gelation kinetics, but a 12% and higher βGP concentration provided a radiopaque solution, which at 37°C, gels immediately. A custom-made in vitro embolization bench test was developed to assess the gel's occlusive properties, and its injectability through a small diameter catheter was verified. Results show that the short-term occlusive properties of the gel were insufficient when using a βGP concentration of 12% w/v (about 0.4M), but that increasing the βGP to 20% (0.6M) allowed an acceleration of the gelation and the immediate blocking of flow above physiological pressure. The contrast agent was rapidly released in solution, such that it would not interfere with future follow-up imaging. In accordance with the literature data, the cytotoxicity of gel extracts increased with βGP concentration and to a lesser extent with VIS concentration. Preliminary in vivo testing showed easy injection by catheter and good visibility under fluoroscopy. These results suggest that radiopaque CH/βGP20%/VIS hydrogels present significant potential as embolizing agents for blood vessels and aneurysms. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1551-1562, 2016.

Hemorrhagic complications of ventriculostomy: incidence and predictors in patients with intracerebral hemorrhage

Ventriculostomy--the placement of an external ventricular drain (EVD)--is a common procedure performed in patients with acute neurological injury. Although generally considered a low-risk intervention, recent studies have cited higher rates of hemorrhagic complications than those previously reported. The authors sought to determine the rate of postventriculostomy hemorrhage in a cohort of patients with intracerebral hemorrhage (ICH) and to identify predictors of hemorrhagic complications of EVD placement. Patients with ICH who underwent EVD placement and had both pre- and postprocedural imaging available for analysis were included in this study. Relevant data were prospectively collected for each patient who satisfied inclusion criteria. Variables with a p < 0.20 on univariate analyses were included in a stepwise logistic regression model to identify predictors of postventriculostomy hemorrhage. Sixty-nine patients were eligible for this analysis. Postventriculostomy hemorrhage occurred in 31.9% of patients. Among all patients with intraparenchymal hemorrhage, the mean hemorrhage volume was 0.66 ± 1.06 cm(3). Stratified according to ventricular catheter diameter, patients treated with smaller-diameter catheters had a significantly greater mean hemorrhage volume than patients treated with larger-diameter catheters (0.84 ± 1.2 cm(3) vs 0.14 ± 0.12 cm(3), p = 0.049). Postventriculostomy hemorrhage was clinically significant in only 1 patient (1.4%). Overall, postventriculostomy hemorrhage was not associated with functional outcome or mortality at either discharge or 90 days. In the multivariate model, an age > 75 years was the only independent predictor of EVD-associated hemorrhage. Advanced age is predictive of EVD-related hemorrhage in patients with ICH. While postventriculostomy hemorrhage is common, it appears to be of minor clinical significance in the majority of patients.

Robot-guided convection-enhanced delivery of carboplatin for advanced brainstem glioma

Patients with diffuse intrinsic pontine glioma (DIPG) have a poor prognosis with median survival reported as 9 months. The failure of systemic chemotherapy to improve prognosis may be due to inadequate penetration of the blood-brain barrier (BBB). Convection-enhanced delivery (CED) has the potential to improve outcomes by facilitating bypass of the BBB. We describe the first use of carboplatin for the treatment of advanced DIPG using a robot-guided catheter implantation technique. A 5-year-old boy presented with a pontine mass lesion. The tumor continued to progress despite radiotherapy. Using an in-house modification to neuroinspire stereotactic planning software (Renishaw Plc., Gloucestershire, UK), the tumor volume was calculated as 43.6 ml. A transfrontal trajectory for catheter implantation was planned facilitating the in-house manufacture of a recessed-step catheter. The catheter was implanted using a neuromate robot (Renishaw Plc., Gloucestershire, UK). The initial infusion of carboplatin (0.09 mg/ml) was commenced with real-time T2-weighted MRI, facilitating estimation of the volume of infusate distribution. Infusions were repeated on a total of 5 days. The catheter implantation and infusions were well tolerated. A total volume of 49.8 ml was delivered over 5 days. T2-weighted MRI on completion of the final infusion demonstrated signal change through a total volume of 35.1 ml, representing 95 % of the targeted tumor volume. Follow-up at 4 weeks revealed clinical signs of improvement and increased T2 signal change throughout the volume of distribution. However, there was tumor progression in the regions outside the volume of distribution. This case demonstrates the feasibility of accurately and safely delivering small-diameter catheters to the brainstem using a robot-guided implantation procedure, and real-time MRI tracking of infusate distribution.

Porcine vena cava as an alternative to bovine pericardium in bioprosthetic percutaneous heart valves

Percutaneous heart valves are revolutionizing valve replacement surgery by offering a less invasive treatment option for high-risk patient populations who have previously been denied the traditional open chest procedure. Percutaneous valves need to be crimped to accommodate a small-diameter catheter during deployment, and they must then open to the size of heart valve. Thus the material used must be strong and possess elastic recoil for this application. Most percutaneous valves utilize bovine pericardium as a material of choice. One possible method to reduce the device delivery diameter is to utilize a thin, highly elastic tissue. Here we investigated porcine vena cava as an alternative to bovine pericardium for percutaneous valve application. We compared the structural, mechanical, and in vivo properties of porcine vena cava to those of bovine pericardium. While the extracellular matrix fibers of pericardium are randomly oriented, the vena cava contains highly aligned collagen and elastin fibers that impart strength to the vessel in the circumferential direction and elasticity in the longitudinal direction. Moreover, the vena cava contains a greater proportion of elastin, whereas the pericardium matrix is mainly composed of collagen. Due to its high elastin content, the vena cava is significantly less stiff than the pericardium, even after crosslinking with glutaraldehyde. Furthermore, the vena cava’s mechanical compliance is preserved after compression under forces similar to those exerted by a stent, whereas pericardium is significantly stiffened by this process. Bovine pericardium also showed surface cracks observed by scanning electron microscopy after crimping that were not seen in vena cava tissue. Additionally, the vena cava exhibited reduced calcification (46.64 ± 8.15 μg Ca/mg tissue) as compared to the pericardium (86.79 ± 10.34 μg/mg). These results suggest that the vena cava may provide enhanced leaflet flexibility, tissue resilience, and tissue integrity in percutaneous heart valves, ultimately reducing the device profile while improving the durability of these valves.

Textile Heart Valve Prosthesis: The Effect of Fabric Construction Parameters on Long-term Durability

The rapid development and success of percutaneous vascular surgery over the last two decades, with the now common stent graft implantation, make this non-invasive technique attractive today even for heart valve replacement. Less traumatic for the patient and also less time consuming, this technique is however in its infancy and restricted to advanced age or terminally ill patients. A major requirement for the use of the method is that the heart valve prosthesis is flexible enough to be folded into the lumen of a small diameter catheter. A standard material used for the construction of arterial grafts and which could also be suitable for engineering heart valve prosthesis is polyester textile fabric. However no data is available in the published technical literature on the long-term durability of this or any other fabric used as a heart valve. The purpose of this research is to study the long-term fatigue behavior of woven polyester fabrics of different yarn and construction factors. In the novel in vitro technique used, a fabric specimen is subjected to combined flexural and tensile fatigue generated by fluid flow under physiological heart valve working conditions. The results obtained show how flexural properties change with fatigue time, which reflects directly on the suitability of a given fabric in such devices. The results also show trends that one can use to develop criteria for designing a fabric most highly suited for use in heart valve application.

Principles of intra-aortic balloon pump counterpulsation

Intra-aortic balloon pump (IABP) remains the most widely used circulatory assist device in critically ill patients with cardiac disease. The National Centre of Health Statistics estimated that IABP was used in 42 000 patients in the USA in 2002. Advances in technology, including percutaneous insertion, smaller diameter catheters, sheathless insertion techniques, and enhanced automation, have permitted the use of counterpulsation in a variety of settings, with greater efficacy and safety.