Inflation Of Balloon Catheter Research Articles

Reliability of temperature and SAR measurements at oesophageal tumour locations

Introduction: For treatment of oesophageal cancer, neo-adjuvant locoregional hyperthermia (HT) has been applied in combination with chemotherapy (ChT) ± radiotherapy (RT) at the institute. Until now, 26 patients were treated within a completed phase I study combining HT with ChT and 29 patients within an ongoing phase II study combining HT with ChT + RT.Methods: HT was given with the 70 MHz AMC-4 waveguide system. Initially, oesophageal temperatures were measured using multi-sensor thermocouple probes (TCs) inside a nasogastric tube (NT), but the question arose whether these measurements were reliable enough to quantify the achieved tumour temperatures accurately. Presently, TCs are mounted on the outside of an inflatable balloon catheter (BC) for better intra-luminal fixation and better contact with the tumour. During 14 treatment sessions in four patients TCs inside a NT and mounted on a BC were used simultaneously. Data from these 14 treatment sessions were used to compare temperature and Specific Absorption Rate (SAR) measurements (‘ΔT-measurements’) using NTs or BCs. To determine the predictive value of the local SAR for the tumour temperatures achieved during treatment, the relation between the initial ΔT and steady state temperature (SST) was evaluated.Results: There was a strong correlation between the temperature measured in the NT (Ttube) and the temperature measured with a BC (Tballoon): R = 0.88 ± 0.13. However, Ttube was on average ∼1°C higher than Tballoon and there was a large variation between the different treatments in the relation between both measurements, rendering Ttube a probably unreliable measure for tumour temperatures. The correlation between the ΔT measured in the NT (ΔTtube) and with a BC (ΔTballoon) was rather weak: R = 0.46 ± 0.25. The correlation between the initial ΔT and the SST was much stronger for the BC measurements, R = 0.78 ± 0.19, than for the NT measurements, R = 0.61 ± 0.23. Thus, ΔTballoon has a higher predictive value for the achieved tumour temperatures than ΔTtube. Both ΔT and SST were generally higher for the NT measurements than for the BC measurements, suggesting an over-estimation of tumour temperatures. Averaged over all treatments in the phase I trial using a NT (20 treatments) or a BC (45 treatments), T90 was significantly higher when measured with a NT.Conclusion: Oesophageal temperature and SAR (ΔT) measurements inside a NT are less reliable than BC measurements. These artefacts are due to bad thermal contact with the tumour tissue and are, therefore, not specific for thermocouple thermometry. For reliable temperature or SAR measurements inside lumina or cavities good thermal contact must be assured, e.g. by using a balloon catheter.

The role of thrombectomy and embolic protection devices

In recent years, it has been demonstrated that restoration of normal coronary flow in the infarct-related artery is not equivalent to the restoration of myocardial perfusion through cardiac microcirculation. Among patients with ST-segment elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI), distal embolization and slow-flow and no-flow phenomenon occur in ∼30% of patients. In these patients, PCI results are less satisfactory, with lower thrombolysis in myocardial infarction (TIMI) or myocardial blush grade (MBG) values, lower rate of a complete resolution of ST-segment elevation, lower left ventricular ejection fraction, and poorer long-term outcome. Studies investigating the usefulness of thrombectomy systems in STEMI showed a similar proportion of patients with TIMI (flow grade 3) in the infarct-related artery in thrombectomy treated patients and control groups. Some small studies with thrombectomy systems or distal protection devices showed encouraging results with preventing slow-flow, no-reflow, and distal embolization, as measured by improved myocardial perfusion by angiography and improved ST-segment elevation resolution after PCI. Large, multi-centre studies did not confirm clinical benefit. New European Society of Cardiology PCI guidelines do not give definitive recommendations regarding the use of embolic protection devices for this group of patients. More randomized trials are needed. However, thrombectomy may be very effective in the situation of large thrombus bulk when present after first balloon catheter inflation. It could be also potentially effective with easy to use thrombectomy system for replacing balloon pre-dilatation before stenting, if studies could prove clinical benefit of such concept for primary PCI.

Selective Left Bronchial Intubation and Left-Lung Isolation in Infants and Toddlers: Analysis of a New Technique

The purpose of this study was to analyze and compare a new technique for left bronchial intubation and left-lung isolation in infants and toddlers without the help of bronchoscopes. In this prospective, unique comparative study, 3 different techniques for left mainstem bronchus intubation and left-lung isolation using a Fogarty catheter as a bronchial blocker were conducted in 11 children under age 4 who required left-lung isolation for left-lung surgery. A new technique for Fogarty catheter insertion and balloon inflation for proper positioning and avoiding displacement during lung handling was used. The first technique was a blind introduction to the left bronchus of the endotracheal tube (ETT) with the head turned to the right and the tube turned to the left at 180 degrees . The second one was to introduce the preshaped Fogarty catheter to the left bronchus. The third one was to intubate the left bronchus using the new technique of a preshaped ETT. No left bronchial intubation could be achieved with the first technique. Left bronchial intubation and isolation were achieved in 2 of 11 by the second technique and 10 of 11 using the third technique. No bulb displacement occurred in any of these during lung handling. The new technique of left bronchial intubation with a preshaped endotracheal tube was simple, safe, and easily accomplished. A Fogarty catheter can be positioned properly without the aid of a smaller bronchoscope once the left bronchus is intubated. Balloon displacement can be avoided completely if the left lung is collapsed properly and completely before the final balloon inflation.

Treatment of recurrent glioblastoma multiforme with GliaSite brachytherapy

In this study, we assess the efficacy of GliaSite brachytherapy in the treatment of patients with recurrent glioblastoma multiforme (GBM). Between 1999 and 2004, 24 patients with recurrent glioblastoma multiforme were treated with the GliaSite Radiation Therapy System (RTS). The GliaSite is an inflatable balloon catheter that is placed in the resection cavity at the time of surgical resection. Low-dose-rate radiation is then delivered locally by temporarily inflating the balloon with an aqueous solution of organically bound (125)I (Iotrex [sodium 3-((125)I)-iodo-4-hydroxybenzenesulfonate]). Patients at the Johns Hopkins Hospital with recurrent GBM, who were previously treated with surgery and external beam radiotherapy, underwent surgical resection followed by GliaSite balloon implantation. Subsequently, the patients received radiation therapy using the GliaSite to a mean dose of 53.1 Gy. Ten patients were male, and 14 patients were female. The mean age was 48.1 years. All patients had pathologically confirmed recurrent GBM. The median Karnofsky performance status (KPS) was 80. Median follow-up time was 21.8 months. At the time of analysis, 18 patients (75%) had died; 6 patients (25%) were alive. Median survival from diagnosis for all patients was 23.3 months. Median survival after GliaSite brachytherapy was 9.1 months. Patients with a KPS > or =70 had a median survival of 9.3 months, whereas patients with a KPS <70 had a median survival of 3.1 months (p < 0.003). Survival was not significantly different between patients receiving 45 Gy and patients receiving a dose greater than 45 Gy. Acute side effects were minor, consisting of mild nausea and/or headache. One patient developed a wound infection. No incidents of meningitis were observed. Late sequelae were rare, but 2 incidents of symptomatic radiation necrosis were observed. One patient developed transient expressive aphasia. GliaSite radiotherapy confers a prolongation of survival in patients with recurrent glioblastoma multiforme compared to historical controls with recurrent GBM. GliaSite therapy leads to a favorable survival outcome of 9.3 months in patients with KPS > or =70, but only 3.1 months in patients with KPS <70. Favorable survival is observed for patients within each recursive partitioning analysis class. Treatment with GliaSite is safe and generally well tolerated. Additional data are needed to fully assess the therapeutic benefit of GliaSite brachytherapy for recurrent GBM.

Treatment of recurrent glioblastoma multiforme with GliaSite brachytherapy

1544 Background: Glioblastoma multiforme is a primary malignancy of the central nervous system that is fatal despite treatment with surgery and standard adjuvant therapy. Long-term control of these tumors is rarely achieved and GBM frequently recurs. In this study, we assess the efficacy of GliaSite brachytherapy in the treatment of patients with recurrent glioblastoma multiforme (GBM). Methods: Between 1999 and 2004, twenty-four patients with recurrent glioblastoma multiforme were treated with the GliaSite Radiation Therapy System (RTS). The GliaSite is an inflatable balloon catheter that is placed in the resection cavity at the time of surgical resection. Low-dose rate radiation is then delivered locally by temporarily inflating the balloon with an aqueous solution of organically bound I-125 (Iotrex [sodium 3-(I-125)-iodo-4-hydroxybenzenesulfonate]). Patients at the Johns Hopkins Hospital with recurrent GBM underwent surgical reresection followed by GliaSite balloon implantation. Subsequently, the patients received radiation therapy using the GliaSite to a mean dose of 53.1 Gy. The mean age was 48.1 years. The median Karnofsky performance status (KPS) was 80. Median followup time was 21.8 months. Results: At the time of analysis, 18 patients (75%) had died; 6 patients (25%) were alive. Median survival from diagnosis for all patients was 23.3 months. Median survival after GliaSite brachytherapy was 9.1 months. Patients with a KPS ≥ 70 had a median survival of 9.3 months while patients with a KPS < 70 had a median survival of 3.1 months (p<0.003). Survival was not significantly different between patients receiving 45 Gy and patients receiving a dose greater than 45 Gy. Acute side effects and late sequelae were rare. Conclusions: GliaSite radiotherapy confers a prolongation of survival in patients with recurrent glioblastoma multiforme compared to historical controls with recurrent GBM. GliaSite therapy leads to a favorable survival outcome of 9.3 months in patients with KPS ≥ 70, but only 3.1 months in patients with KPS < 70. Favorable survival is observed for patients within each recursive partitioning analysis (RPA) class. Treatment with GliaSite is safe and generally well tolerated. No significant financial relationships to disclose.

Preoperative Balloon Sealing of a False Ascending Aortic Aneurysm for Safe Redo Sternotomy

Sternal contact of aortic aneurysms in redo operations may require specific techniques to safely control bleeding during sternotomy and surgical dissection. This is the first report on the preoperative use of an inflatable balloon to prevent massive hemorrhage by inserting the balloon--a procedure performed in the cardiac catheterization laboratory--before rethoracotomy. A false ascending aortic aneurysm was successfully sealed by transaortic wire-guided balloon placement from the iliac artery. Gentle traction on the inflated balloon catheter, which was placed inside the false aneurysm, effectively sealed the entrance to the aneurysm. A straightforward median redo sternotomy procedure was subsequently performed without blood loss from the unavoidably opened aneurysm. My colleagues and I propose this technique for aneurysms of mycotic or anastomotic origin, which have an anatomically distinct entry channel.

The use of a balloon catheter to improve evaluation in anorectal manometry

The squeeze pressure in the anal canal reflects the contribution of the external anal sphincter and is normally assessed manometrically by asking patients to contract their anal muscles. However, this is an artificial situation as normally the external sphincter contracts to retain rectal content. Some patients with normal anal sphincter anatomy and innervation record low squeeze pressures suggesting that the concept of voluntary squeeze is foreign. The aim of this study was to examine whether squeezing to retain a balloon mimics the physiology of defaecation more accurately. Patients undergoing routine anorectal manometry testing had in addition the inflation of a balloon catheter to the volume of the first and sustained sensation to simulate a faecal bolus within the rectum. The patient was asked to retain it when the balloon was subjected to gentle traction, thus contracting their anal sphincter to prevent passage of the balloon. Squeeze pressure was measured in response to voluntary contraction, the pressure generated to retain the balloon, then voluntary contraction again. Eighteen women and 2 men were tested. The median maximal squeeze pressures with the routine assessment was 131.0 cmH2O. This increased to 210.0 cmH2O when the patients attempted to retain the balloon and fell to 165.4 cmH2O when patients were reassessed with voluntary squeeze postintervention. 15 of the patients improved their squeeze pressures with traction on the balloon. External anal sphincter contraction is difficult for some patients to perform on request. With traction on a balloon catheter anal squeeze pressures improved in most patients. This indicates that many patients perform maximal anal squeeze pressures better once that muscle group has been tested in a more normal physiological function. This simple technique could improve the accuracy of anorectal manometry results and evaluation in a larger population of symptomatic patients is warranted.

MRI of the Upper Airway and McCoy-Balloon Laryngoscopy with Left Molar Approach in a Patient with Arthrogryposis Multiplex Congenita and Previous Unsuccessful Endotracheal Intubation

To the Editor: A patient with amyoplasia congenita (1) and previous unsuccessful endotracheal intubation with standard/McCoy laryngoscopy, intubating laryngeal mask, and fiberoptic bronchoscopy, was scheduled for scoliosis correction. Simplified airway risk index score (2) amounted to 10 (Table 1). Preoperative magnetic resonance imaging (MRI) revealed long, counterclockwise-rotated, and left-shifted epiglottis, clockwise-rotated hyoid, and short epiglottis tip-to-retropharyngeal wall distance (Fig. 1); anatomic abnormalities were probably explanatory of preceding intubation failure (Fig. 1, see legend). Following anesthesia-induction, a number 4 McCoy blade carrying a 7F Fogarty catheter (Fig. 2A) (3) was introduced through left mouth corner and above the left molars (4). Blade-tip was directed posteromedially (4), epiglottis was visualized, and blade-tip was advanced deep into vallecula. The handle was rotated clockwise so that its convex surface was parallel to line AT of Figure 1B. Fogarty catheter balloon inflation (Fig. 2B), forceful laryngoscope elevation, and external thyroid pressure resulted in exposure of posterior glottis commissure. A gum elastic bougie was introduced into the larynx, and a 6.5-mm-internal diameter endotracheal tube passed over it into the trachea. Conclusively, combined sagittal and transverse upper airway MRI sections may aid in difficult airway management planning. Anatomic abnormality-associated difficulties with epiglottis lifting may be attenuated with “left molar” McCoy-balloon laryngoscopy.Table 1: Preoperative Airway EvaluationFigure 1.: Preoperative magnetic resonance imaging sections of the upper airway. A, sagittal section 1 cm left to midline during “quiet” inspiration. The black dot represents the root of the epiglottis and the white dot represents its tip; epiglottis length amounts to 3.23 cm. The distance between epiglottis tip and retropharyngeal wall (R) is approximately 3 mm. H = hyoid bone; V = vallecula epiglottica; G = glottis. B, transverse section at the level of epiglottis tip (T). The epiglottis is shifted to the left and rotated counterclockwise; the angle between line AB and upper airway transverse axis (CD) is 25.1 degrees; line AB is tangential to the edges of the epiglottis laryngeal surface. The hyoid bone is rotated clockwise. C1 = right greater cornu of hyoid; C2 = left greater cornu of the hyoid. During the preceding, failed intubation attempts (see also main text), the abnormal epiglottis-hyoid anatomic relationship was the probable cause of ineffective epiglottis lifting with standard/McCoy laryngoscopy, whereas laryngeal mask insertion could have resulted in downward-folding of the elongated epiglottis; the elongated/left-shifted epiglottis probably resulted in inability of the endoscopist to advance a fiberscope around the epiglottis side and through the vocal cords. During the laryngoscopy reported herein, the McCoy-balloon blade was introduced into the vallecula epiglottica and then rotated clockwise so that its convex surface became approximately parallel to line AT; this maneuver along with the balloon-enhanced capability of upward hyoid/epiglottis lifting (see also Fig. 2B) should have been the major factors of the successful endotracheal intubation.Figure 2.: The modified number 4 McCoy-balloon laryngoscope blade used during the difficult airway management procedure reported herein. A 7F Fogarty catheter is attached on the concave surface of the blade. A, the laryngoscope blade was introduced into the left corner of the mouth with the McCoy lever pressed approximately halfway toward the laryngoscope handle, resulting in increase of blade tip angulation by 25–30 degrees. The tip of the Fogarty catheter is positioned behind the midpoint (white dot) of the cylindrical edge of the blade (Ε). B, modified blade configuration just after its “optimal” placement into the vallecula epiglottica (see also main text). The Fogarty catheter balloon is inflated with 2 mL of air.Spyros D. Mentzelopoulos, MD, PhD, DEAA Apostolos Armaganidis, MD, PhD Dimitra Niokou, MD Paraskevi Matsota, MD Maria Tzoufi, MD, DEAA Nikos Kelekis, MD, PhD Kostantinos Soultanis, MD, PhD Nikos Oikonomopoulos, MD Georgia Kostopanagiotou, MD, PhD Departments of *Intensive Care Medicine, †Anesthesiology, ‡Radiology, and §Orthopedic Surgery Attikon University Hospital Athens, Greece [email protected]

Gliasite radiotherapy system for treatment of recurrent malignant glioma: A multi-institutional analysis

Gliasite radiotherapy system for treatment of recurrent malignant glioma: A multi-institutional analysis

Angioplasty-induced superoxide anions and neointimal hyperplasia in the rabbit carotid artery: suppression by the isoflavone trans-tetrahydrodaidzein

Reactive oxygen species (ROS) may contribute to the development of stenosis in balloon catheter injured arteries. As isoflavones exhibit effects on ROS and cell proliferation In vitro that appear useful in preventing such stenosis, we examined the effects of the isoflavone trans-tetrahydrodaidzein ( trans-THD) on development of neointimal lesions in relation to elevations in ROS in balloon catheter injured arteries. Carotid arteries of rabbits treated with either vehicle or trans-THD were injured with an inflated balloon catheter and cell proliferation, collagen content, ROS and vessel structure determined over the ensuing 28 days. Seven days after injury neointimal smooth muscle cell proliferation was reduced by 50% ( p < 0.05) whilst medial cell proliferation was largely unaffected ( p > 0.10). At this time ROS levels in vehicle-treated rabbits were elevated 3-fold compared to uninjured arteries ( p < 0.05). Treatment with trans-THD reduced ROS levels to those seen in uninjured arteries ( p > 0.05). The antiproliferative effects of trans-THD on intimal cell proliferation persisted 14 days after the injury, and twenty eight days after injury the size of the lumen in trans-THD-treated animals was 27% greater ( p < 0.05) and the intima area: vessel area reduced by 40% ( p < 0.05). The small effects of trans-THD on collagen accumulation was not statistically significant, indicating that effects on neointimal cell proliferation was the major mechanism by which this isoflavone attenuated development of the neointima. Intimal smooth muscle cells and ROS represent potentially important targets for the antiproliferative actions of trans-THD in injured arteries. Strategies using such isoflavones may be useful for preventing restenosis after vascular manipulations in humans.

“IOMaster 7D”—a new device for virtual neuroendoscopy

Purpose: Within a scope of a cooperative project called “HapticIO” (funded by the German Ministry of Education and Research (BMBF)), a completely new force feedback device “IOMaster 7D” was intended to be developed for simulation of endoscopic ventriculo-cisternostomy (VCS). Methods: A VR model for endoscopic ventriculostomy was generated based on a MRI data set of a real hydrocephalic brain. Different software modules were used for segmentation (VESUV), modelling (KisMo) and visualization (KISMET). The software modules were implemented on a WIN32 platform and are running on Windows-NT, Win2000 or WinXP. A force feedback system for capturing of the position of both the trocar and the acting instrument was developed. Large arms are counterbalanced to reduce gravitational forces and torques. The position and orientation of the input handle is determined by taking the joint angles of the linkages and using the forward kinematics calculation. Force data returned by the simulation is mapped to a set of torques to be produced by the motors by using a so-called Jacobian transformation. Real microsurgical instruments (MINOP, Aesculap, Germany) were used and adapted to the simulator to provide for a design and haptic properties close to real situation in the OR. The system was evaluated in a pilot series. Results: The force feedback system IOMaster 7D offers 7 degrees of freedom and consists of two coupled force feedback elements. Both the trocar and the acting instruments (scissor, bipolar coagulation, forceps, inflatable balloon catheter) are captured separately. In this way, the trocar's position determines the view of the endoscopic 30° lens camera, the access to the target and the possible operating range of the instruments. A complex elastodynamic hydrocephalic configured ventricular system with realistic proportions and anatomical structures could be modelled. An interactive virtual preparation with force feedback was implemented coupling real surgical instruments (MINOP) with the force feedback system. The VR system provides different interactions like axial movement or rotation of the instruments, cutting, grasping as well as realistic elastodynamic deformations of the ventricle wall. First evaluations proved a reduction of the median failure rate and a reduction of the median required time to reach the target. Analysis of the total distance of instruments movement also showed a reduction. Conclusion: VR systems can simulate realistic and real-time surgical procedures and may open new perspectives for the neurosurgical training. The training of potentially hazardous procedures can be uncoupled from the patient resulting in a reduction of surgical morbidity. The integration of haptic information increases the quality of these training systems. The definition of no-touch areas and targets and the possibility of automatic registration of both kinetic parameters, failure rate and the time course of the procedure provide objective criteria for the appreciation of a learning effect.

Radiation Safety Considerations In GliaSite 125I Brain Implant Procedures

The traditional approach to treatment of certain malignant brain tumors involves permanent implantation of I seeds sequential to tumor's resection. This approach has recently been changed for patients with unifocal recurrent gliomas. What began during the 1990's as a large clinical trial utilizing GliaSite Radiotherapy System, is currently becoming standard of care. This radiotherapy system consists of an inflatable balloon catheter, 2, 3, or 4 cm diameter, which is surgically placed in the tumor resection cavity; its positioning and the level of conformity within the cavity are verified via MRI imaging with contrast. The balloon is then filled with appropriate volume of I in the liquid form. Radiation treatment prescription dose ranges from 40 to 60 Gy (4,000 to 6,000 rads). This is accomplished by allowing 2.77 to 16.6 GBq (75 to 450 mCi) of I to remain in the balloon for 3-5 d. Numerous technical, dosimetric, and logistical considerations arise when handling large quantities of iodine necessary to perform GliaSite procedures. They require coordination of efforts of several hospital departments and the institution's RSO-in our case, two RSOs, at the University of Colorado Hospital and University of Colorado Health Sciences Center hold separate radioactive materials licenses. Based on our experiences and those of others, we conclude that, with appropriate guidance and care, these procedures can be performed safely without excessive restrictions.

Visualization and tracking of an inflatable balloon catheter using SSFP in a flow phantom and in the heart and great vessels of patients.

Passive catheter tracking involves direct interaction between the device and its surroundings, creating a local signal loss or enhancement of the image. Using only standard balloon catheters filled with CO(2) and imaged with a steady-state free precession sequence, it was possible to visualize and passively track catheters in a flow phantom and in the heart and great vessels of 20 patients without any additional image processing. The phantom work demonstrated that it was advantageous to sacrifice spatial resolution in order to increase temporal resolution. Frame rates greater than 10/sec were necessary for ease of catheter manipulation. Although only the tip of the catheter was visualized, this technique proved to be effective in patients undergoing cardiac catheterization.

Significant rectal and bladder dose reduction via utilization of foley balloon catheters in high-dose-rate tandem and ovoid intracavitary brachytherapy of the uterine cervix

Purpose To ascertain the potential for dose reduction to bladder and rectal points by using intravaginal Foley balloon catheters as a mechanism for structural displacement during tandem and ovoid high-dose-rate intracavitary brachytherapy of the uterine cervix. Methods and materials In 22 patients, two Foley balloons were placed intravaginally, with one balloon placed anterior to the tandem and one posterior, as close to the flange as patient geometry allowed. A series of 57 consecutive digitized treatment plans was assessed with and without liquid contrast inflation of Foley catheter balloons. Planning X-rays were acquired and digitized. Software calculated dose was then defined for two bladder and two rectal points, both with and without Foley balloon inflation. Results were then assessed using parametric statistical analysis. Results Collectively and between equivalent points, a statistically significant ( p ≤ 0.01) diminution in calculated dose was observed with inflation of intracavitary balloon catheters, with a mean reduction in calculated dose of 16% and 17.6% for bladder and rectal points, respectively. Conclusion The potential advantages available from dose reduction using intracavitary balloon catheters include decreased high-dose-rate–induced organ toxicity, case-by-case customizability, and low cost of implementation. As such, further exploration of this technique is warranted.

An inflatable balloon catheter and liquid 125I radiation source (GliaSite Radiation Therapy System) for treatment of recurrent malignant glioma: multicenter safety and feasibility trial.

In this study the authors evaluated the safety and performance of the GliaSite Radiation Therapy System (RTS) in patients with recurrent malignant brain tumors who were undergoing tumor resection. The GliaSite is an inflatable balloon catheter that is placed in the resection cavity at the time of tumor debulking. Low-dose-rate radiation is delivered with an aqueous solution of organically bound iodine-125 (lotrex [sodium 3-(125I)-iodo-4-hydroxybenzenesulfonate]), which are temporarily introduced into the balloon portion of the device via a subcutaneous port. Adults with recurrent malignant glioma underwent resection and GliaSite implantation. One to 2 weeks later, the device was filled with Iotrex for 3 to 6 days, following which the device was explanted. Twenty-one patients with recurrent high-grade astrocytomas were enrolled in the study and received radiation therapy. There were two end points: 1) successful implantation and delivery of brachytherapy; and 2) safety of the device. Implantation of the device, delivery of radiation, and the explantation procedure were well tolerated. At least 40 to 60 Gy was delivered to all tissues within the target volume. There were no serious adverse device-related events during brachytherapy. One patient had a pseudomeningocele, one patient had a wound infection, and three patients had meningitis (one bacterial, one chemical, and one aseptic). No symptomatic radiation necrosis was identified during 21.8 patient-years of follow up. The median survival of previously treated patients was 12.7 months (95% confidence interval 6.9-15.3 months). The GliaSite RTS performs safely and efficiently. It delivers a readily quantifiable dose of radiation to tissue at the highest risk for tumor recurrence.

The Accuracy of Endometrial Biopsy and Saline Sonohysterography in the Determination of the Cause of Abnormal Uterine Bleeding

This study was conducted to investigate the use of endometrial biopsy and saline sonohysterography in the evaluation of abnormal uterine bleeding. The results of this combination were compared with pathologic results from hysteroscopy/ dilatation and curettage or hysterectomy. Study participants were women aged 25 to 69 years with persistent uterine bleeding despite at least 3 months of medical treatment. Of 144 women who entered the study, 30 did not complete the protocol, including 1 who could not tolerate the pain associated with saline sonohysterography and 20 who did not have surgical treatment. One hundred thirteen patients had an initial endometrial biopsy 6 or 7 weeks before saline sonohysterography. Sonohysterography was performed by placing an inflatable balloon catheter in the cervix. After the balloon was inflated with approximately 2 ml of sterile water, a transvaginal ultrasound probe was inserted into the vagina; the uterine cavity was further distended with 10 to 20 ml of sterile saline solution during the ultrasound examination. Forty-seven women (41.6%) had normal surgical findings (secretory, proliferative, or atrophic endometrium). Sixty-six women had abnormal histopathologic findings, including 37 benign and 2 malignant endometrial polyps. One malignant and 22 benign submucosal myomas were diagnosed. Four women had endometrial hyperplasia. Endometrial biopsy and sonohysterography correctly identified 64 patients with abnormal pathology but failed to diagnosed 2 patients with intrauterine pathology; it did predict negative findings in 2 women who were positive in the surgical specimen. The combination also overdiagnosed 14 women as positive who had negative surgical specimens. Thirty-three patients were correctly identified as negative. The sensitivity and specificity of endometrial biopsy and saline sonohysterography were 0.970 (0.886-0.995) and 0.702 (0.550-0.822), respectively. The positive and negative predictive values were 0.821 (0.714-0.895) and 0.943 (0.796-0.990), respectively.

Preclinical evaluation of a novel device for delivering brachytherapy to the margins of resected brain tumor cavities.

The objectives of this study were to evaluate the safety and performance of a new brachytherapy applicator in the treatment of resected brain tumors in a canine model. The brachytherapy applicator is an inflatable balloon catheter that is implanted in the resection cavity remaining after a brain tumor has been debulked. After implantation the balloon is inflated with Iotrex, a sterile solution containing organically bound iodine-125. The low-energy photons emitted by the iodine-125 deposit a therapeutic radiation dose across short distances from the surface of the balloon. After delivery of a prescribed radiation dose to the targeted volume, the radioactive fluid is retrieved and the catheter removed. Small resections of the right frontal lobe were performed in large dogs. Magnetic resonance (MR) images were obtained and used to assess tissue response and to measure the conformance between the resection cavity wall and the balloon surface. In four animals a dose ranging from 36 to 59 Gy was delivered. Neurological status and histological characteristics of the brain were assessed in all dogs. Implantation and explantation as well as inflation and deflation of the device were easily accomplished and well tolerated. The device was easily visualized on MR images, which demonstrated the expected postsurgical changes. The resection cavity and the balloon were highly conformal (range 93-100%). Histological changes to the cavity margin were consistent with those associated with surgical trauma. Additionally, radiation-related changes were observed at the margins of the resection cavity in dogs in which the brain was irradiated. This balloon catheter and 125I radiotherapy solution system can safely and reliably deliver radiation to the margins of brain cavities created by tumor resection. Results of this study showed that intracranial pressure changes due to balloon inflation and deflation were unremarkable and characteristic of the imaging properties and radiation safety profile of the device prior to its clinical evaluation. Clinically relevant brachytherapy (adequate target volume and total dose) was accomplished in all four animals subjected to treatment.

Biomechanical Analysis of Optimized Balloon Configuration to Reduce Incidence of the Restenosis of Vascular Lumen after Interventional Balloon Catheter Inflation

Biomechanical Analysis of Optimized Balloon Configuration to Reduce Incidence of the Restenosis of Vascular Lumen after Interventional Balloon Catheter Inflation

Angiotensin-converting enzyme inhibition enhances a subthreshold stimulus to elicit delayed preconditioning in pig myocardium

OBJECTIVESWe assessed the effect of angiotensin-converting enzyme (ACE) inhibition in combination with a subthreshold preconditioning (PC) stimulus to elicit delayed preconditioning against infarction in pig myocardium.BACKGROUNDBradykinin triggers early PC. Angiotensin-converting enzyme inhibitors increase local bradykinin levels via inhibition of kinin breakdown and have been shown in experimental studies to augment early protection afforded by PC. A role for bradykinin in eliciting delayed PC has not so far been identified.METHODSWe used a two-day protocol. On day 1 (closed chest), pigs were either sham-operated (group 1) or preconditioned, using balloon catheter inflation of the left anterior descending (LAD) coronary artery, with either a full (4 × 5 min PC, group 2) or subthreshold PC stimulus (2 × 2 min PC, group 3). Additional groups were pre-treated with perindoprilat (0.06 mg/kg i.v.) before sham (group 4) or subthreshold PC (group 5). On day 2 (open chest), all pigs were subjected to 40 min occlusion of the LAD followed by 3 h of reperfusion. Infarct size was determined by tetrazolium staining.RESULTSGroup 1 had a mean infarct size of 42.8 ± 3.2% of the risk zone. Preconditioning with 4 × 5 min reduced the infarct size to 19.5 ± 3.9% (p < 0.05). Groups 3 and 4 had infarct sizes not statistically different from group 1. However, combining perindoprilat with subthreshold PC resulted in a significant limitation of the infarction (18.4 ± 3.1% p < 0.05), comparable with group 2.CONCLUSIONSThis is the first study to show that ACE inhibition can augment a mild ischemic stimulus to induce a protected state 24 h later.

Setting a New Gold Standard

Setting a New Gold Standard