Optical Catheter Research Articles

Application of Anal Manometry in the Planning for Anal Fistula Surgery

Anal fistula does not heal spontaneously without surgery, and anal function should be preserved after muscle dissection, which is a challenge even to the most experienced surgeon. In order to develop a planner for anal fistula surgery, anal manometry used in the measurement of pressures in the anal canal to investigate the anal function is reviewed. In this review paper, current techniques are described and compared with each other, and technical and clinical challenges are discussed. There are four types of catheters used to measure anal sphincter pressure: water-perfused, solid-state, air-coupled, and fiber optic catheter. Parameters acquired by anal manometry and their relationship with fecal incontinence after anal fistula surgery are discussed. Vectormanometry can provide the pressure profile along the anal canal in three dimensional space, pressure vectorgram, and cross-sectional radial asymmetry, which have more advantages than the conventional method. Understanding the technology and development of anal manometry is critical for the anal fistula surgical planning. A novel design is highly desired for 3D pressure profile measurement along the entire anal canal simultaneously without pulling the catheter.

Intracranial pressure is elevated at 24 h post‐stroke in mice

AbstractBackgroundIt has long been assumed that post‐stroke intracranial pressure (ICP) elevation occurs because of large infarct and edema volumes. However, we have repeatedly shown ICP elevation at 24 h post‐stroke in the presence of little to no edema in rats. Biological processes are often conserved across species and types of injury. Therefore, we aimed to determine if an ICP rise occurs at 24 h post‐stroke in the presence of small infarct and edema volumes in mice.MethodsMice were randomized by random number table to either photothrombotic stroke or sham surgery (n = 15). Epidural ICP was recorded using a fiber optic catheter at 1 h post‐stroke (baseline) and between 23 and 24 h post‐stroke.ResultsICP was significantly higher at 24 h compared to baseline in stroke animals (n = 6; 10.71 ± 6.45 mmHg vs. 3.74 ± 2.20 mmHg, respectively; p = 0.03). ICP at 24 h was also significantly higher in stroke mice compared to sham (n = 6; 3.45 ± 1.43 mmHg; p = 0.02). There was no change in ICP in sham mice (p = 0.9). Edema volumes in stroke animals were small (0.04 ± 0.04 mm3) and unlikely to have caused significant ICP elevation.ConclusionThis study provides evidence of an edema‐independent ICP elevation following small ischemic stroke in mice. The occurrence of this rise supports our findings in other species and suggests it is caused by a previously undescribed mechanism.

Trends in outcomes associated with the use of Auryon atherectomy system in a real-world setting

BackgroundWhile endovascular approaches are considered first line treatment for stenosis or occlusion of the lower limb arteries, major dissections and embolic events remain procedural risks. Newer technologies are needed which limit these complications while achieving desired clinical outcomes. MethodsThe Auryon atherectomy system (AngioDynamics) consists of a 355-nm wavelength solid-state Nd:YAG short pulse laser combined with dedicated optical catheters. This single-center, retrospective chart review assessed the safety and efficacy of this device in patients with PAD treated at our center between March and December 2020. ResultsA total of 55 patients were included. Mean age was 73.7 ± 9.3 years with 63.6 % of patients being males. Lesions were above the knee only for 16.4 % of patients, below the knee only for 3.6 %, and both above and below the knee for 80.0 % of patients. One patient had in-stent restenosis. Chronic total occlusions and critical limb ischemia were present for 43.6 % of patients respectively. Procedural success, defined as <30 % residual stenosis without any complications, was achieved in 85.5 % of patients. Stenosis/re-occlusion occurred in 25.5 % of patients at a mean of 168.9 ± 73.4 days with resultant target lesion revascularization (TLR) at 218.3 ± 92.4 days. Four patients underwent minor amputations. No patients experienced procedure-related complications. One patient died unrelated to the procedure. ConclusionThe Auryon laser system was shown to be safe and effective in this real-world patient population with no procedural adverse events or deaths and improvements in patient outcomes.

Development of Novel Balloon-Integrated Optical Catheter for Endoscopic and Circumferential Laser Application.

The current study aims to demonstrate the feasibility of a novel balloon-integrated optical catheter (BIOC) to achieve endoscopic laser application for circumferential coagulation of a tubular tissue structure. Both optical and thermal numerical simulations were developed to predict the propagation of laser light and a spatio-temporal distribution of temperature in tissue. Ex vivo esophagus tissue was tested with 980nm laser light at 30 W for 90s for quantitative evaluations. In vivo porcine models were used to validate the performance of BIOC for circumferential and endoscopic laser coagulation of esophagus in terms of acute tissue responses post-irradiation. Optical simulations confirmed that a diffusing applicator was able to generate a circumferential light distribution in a tubular tissue structure. Both numerical and experimental results presented that the maximum temperature elevation occurred at 3-5mm (muscle layer) below the mucosa surface after 90 s irradiation. In vivo tests confirmed the circumferential delivery of laser light to a deep muscle layer as well as no evidence of thermal damage to the esophageal mucosa. The proposed BIOC can be a feasible optical device to provide circumferential laser irradiation as well as endoscopic coagulation of tubular esophagus tissue for clinical applications.

Abstract P131: Cerebral Venous Sinus Thrombosis Risk Factors, Treatments, And Sequelae: 2011-2019

Introduction: Cerebral venous sinus thrombosis (CVST) is a rare but potentially debilitating thrombosis affecting 3-4 cases per million adults in the United States. Risk factors are thought similar to venous thrombosis, but there is little epidemiologic data corroborating this assertion. Concern about a possible association between the Janssen (Johnson and Johnson) and Oxford-AztraZenaca COVID-19 vaccines and cases of CVST resulted in increased global attention to this condition. Thus, large epidemiological assessment of the risk factors, treatment and outcomes of CVST are needed. Objective: Estimate the distributions of risk factors antecedent to CVST diagnosis, report CVST treatments in clinical practice, and potential sequelae of CVST in a large retrospective cohort of adults with CVST in the United States. Methods: MarketScan Commercial and Medicare Supplemental administrative databases were employed to assess CVST diagnosed between 2011 and 2019 in the U.S. Validated International Classification of Disease (ICD) codes and receipt of an outpatient anticoagulant (either oral or subcutaneous anticoagulant) prescription within 30 days of the ICD code identified incident CVST. Antecedent clinical characteristics, treatments, and sequelae of CVST were identified using inpatient, outpatient, and prescription data. For outcomes, proportions and incidence with 95% confidence intervals (CIs) were calculated, stratified by sex. Results: We identified 1,869 CVST patients. Of these 1,314 (70%) were female, with 200 (10%) events identified as a pregnancy-related CVST. The average age was 41 years for females and 48 years for men. Among women, 24.7% were on hormonal therapy (oral contraceptive, estrogen, and progestin) prior to diagnosis. Men had a higher prevalence of comorbidities, such as diabetes (15% men vs. 9% women) and cancer (19% men vs. 10% women). Oral anticoagulant (OAC) use was the most common treatment for CVST in both men (88%) and women (85%) and did not vary by sex. Use of procedures to treat CVST, optic nerve fenestration and catheter directed thrombolysis, were 0.5% and 4.1%, respectively. The most common sequela after CVST was incidence of intracranial hypertension (Incidence: 4.2 per 100 person-years; 95% CI: 3.3, 5.1) and palliedema was rare. Conclusions: Overall, a majority of CVST patients were women of reproductive age. Our findings suggest a potential association with both endogenous (pregnancy) and exogenous (oral contraceptives, HRT) hormones which needs further study. In our sample, CVST was managed with oral anticoagulants, regardless of sex, and intracranial hypertension was elevated following CVST. This large claims-based analysis is a descriptive insight into the risk factors and management of CVST, a rare and debilitating condition.

Comparison of venous hemoglobin saturation measurements obtained by in vivo oximetry and calculated from blood gas analysis in critically ill dogs

To compare in vivo central venous hemoglobin saturation measurement (ScvO2 ) using a fiber optic catheter with saturation calculated from blood gas analysis in critically ill dogs. Prospective observational study. University veterinary teaching hospital intensive care unit. A convenience sample of 20 dogs with severe illness. Dogs were instrumented with either a central venous catheter with an integrated fiber optic cable or a conventional catheter with a fiber optic probe inserted through its distal port. Baseline saturation was measured with the fiber optic system (FSO2 ), then monitored continuously. Central venous blood was collected for analysis and FSO2 was recorded by the principal investigator (PI) or nursing staff participating in data collection (staff) at baseline and at 1, 2, 3, and 6 hours. Hemoglobin oxygen saturation (SO2 ) values calculated using human Bohr coefficients were taken directly from the analyzer (GPSO2 ), and were also calculated using temperature-correction and canine Bohr coefficients (RSO2 ). Ninety-seven paired measurements from 20 dogs were analyzed. FSO2 obtained by the PI (n = 41) had better agreement with both GPSO2 (concordance correlation coefficient ρc = 0.926 vs 0.5562) and RSO2 (ρc = 0.75 for PI vs 0.54) than did staff (n = 56). RSO2 values were always smaller than GPSO2 . FSO2 - GPSO2 differences were smaller when measurements were collected by the PI versus Staff (mean difference 0.21 vs -6.6, respectively, P<0.02). Thirty-six of 41 FSO2 values obtained by PI were within 5% of GPSO2 . Concordance between FSO2 and either calculation method was low, but was better when performed by PI. The larger difference between methods when using RSO2 suggests a positive bias by FSO2 . Difficulty obtaining stable measurements may have contributed to the poor concordance between methods within Staff.

Acute detection of optical tissue changes in real-time during pulsed field ablation (PFA)

Abstract Background It has been established in previous animal and human studies that it is possible to assess lesion formation in real-time using optical means during the application of radiofrequency (RF) energy in cardiac ablation procedures. The optical interrogation was accomplished using a novel catheter and instrument system whereby the catheter has embedded optical fibers that transmit and receive light from the instrument. Purpose The aim of this study was to see if there are similar indications of lesion formation, detected by the same optical means, during the application of pulsed field ablation (PFA) energy to cause lesions through electroporation. Methods A series of 3 anesthetized pigs underwent PFA in the right atrium. An 8-electrode circular catheter was placed high in the right atrium, near the superior vena cava, to simulate pulmonary vein isolation as part of an AF ablation procedure. The optical catheter was placed adjacent to the circular catheter between stimulation electrode pairs. A bolus of adenosine was administered to create a window of asystole to avoid stimulation on the T-wave. Bipolar PFA was delivered immediately post drug infusion and the optical signature from the catheter was recorded and displayed in real-time. Electrograms were recorded and the mapping of the lesion was performed with the optical catheter at the following time intervals post PFA delivery: 0 min, 15 min, 1 hour, and 3 hours. Necropsy and histology followed the procedure. Results The optical signal is distinctly higher in intensity during the PFA pulse train. The optical signal showed an immediate significant decrease and a slow but steady decay over the mapping interval. Electrogram reduction accompanied PFA application and also showed a marked reduction over the mapping interval. The optical signal amplitudes were markedly lower when on the lesion compared to healthy non-ablated myocardium as predicted. Conclusions Preliminary results indicate that optical mapping detects immediate tissue changes during PFA at these energy levels and hence could be is a viable method of evaluating lesion formation during and after PFA energy application. The optical signal indicates that cell damage occurs immediately at these energy levels and continues to progress slowly in lesions made by PFA energy compared to those made by RF energy. The findings also suggest that optical mapping can identify acute lesions made with PFA energy in real-time implying that optical mapping could evolve as a PFA gap detector. Funding Acknowledgement Type of funding source: None

Light triggering goldsomes enable local NO-generation and alleviate pathological vasoconstriction

While nitric oxide (NO) can remedy vasoconstriction, inhalation of NO may cause systematic toxicity. We report a goldsome, which comprises a hollowed poly(lactic-co-glycolic acid) (PLGA) polymersome with S-nitrosoglutathione (GSNO, a NO donor) molecules and gold nanoparticles (Au NPs) incorporated in its hydrophilic core and hydrophobic membrane, respectively. Photothermal heating caused breakdown of polymersomes and enabled NO generation through reaction between GSNO and Au NPs. Photo-illumination at the zebrafish head led to local NO generation and selective cerebral vasodilation while it had little effects in regions away from the illumination site, and effectively mitigated hypoxia induced cerebral vasoconstriction. We demonstrate a translational potential by showing photo-stimulated NO generation with a clinical intravascular optical catheter. In conclusion, the goldsome, which enables light stimulated local NO generation and can be delivered with clinical intravascular optical catheters, should extend applications of NO therapies while surmounting limitations associated with systemic administration.

Abstract 409: Investigating the Role of the Mitochondrial Calcium Uniporter (mcu) in Calcium Regulation of Cardiac Mitochondria Using Transmural Spectroscopy and an Integrating Sphere

Cardiac mitochondria uptake calcium through the mitochondrial calcium uniporter (MCU). To better understand the role of MCU and mitochondrial calcium in regulating heart physiology and pathophysiology, we developed a method to measure mitochondrial matrix calcium in beating, perfused hearts. Langendorff perfusing hearts are loaded with 4.5 uM rhod-2-AM at 30°C and then perfused at 37°C to washout uncleaved dye. We determined that rhod-2 localized primarily to the mitochondria under our loading conditions, as shown by loading in a heart expressing a GFP-tagged mitochondrial outer membrane protein and analyzing heart slices under super resolution microscopy. Further, addition of Mn 2+ , which quenches cytosolic rhod-2, has little effect on rhod-2 signal. We insert an optical catheter with both white light and 532nm laser into the left ventricle and interleaved the collection of spectra from both light sources. The perfused heart is center mounted in an integrating sphere for spectra collection. The light passes through the ventricle and reflects off the integrating sphere resulting in a near uniform sampling of the transmitted light. Spectral properties from both light sources are determined using a rapid scanning spectrophotometer. Myoglobin oxygenation, cytochrome redox state, and rhod-2 loading are determined by white light absorbance. Ca 2+ bound rhod-2 emission is determined by removing background tissue effects from laser emission spectra and normalizing to tissue absorbance. Using this method we are able to measure changes in Ca 2+ and cytochromes during treatments such as isoproterenol and ischemia-reperfusion. The use of an integrating sphere transmural spectroscopy provides us an unique method to study mitochondrial Ca 2+ signaling in perfused mouse heart loaded with Rhod-2.

Hallazgos colonoscópicos en pacientes atendidos en una institución de salud del municipio de Barrancabermeja, Santander

Introducción. La colonoscopia es una exploración visual de la mucosa del colon, la cual consiste en la introducción de una sonda óptica flexible por el ano. Dentro de sus objetivos está la localización de lesiones de una manera muy precisa, obtener biopsias para su análisis al microscopio, realizar diversos procedimientos terapéuticos o diagnosticar lesiones pequeñas no detectables por métodos imagenológicos tradicionales. El objetivo del presente artículo es describir los hallazgos colonoscópicos en pacientes adultos de una institución prestadora de servicios de salud. Metodología. Estudio observacional, transversal con componente analítico, la información se recolectó de manera retrospectiva, en pacientes mayores de 18 años en ambos sexos, a los cuales se les realizó colonoscopia en una institución prestadora de servicios de salud de segundo nivel. Resultados. Se practicaron 521 procedimientos colonoscópicos en 291 mujeres y 230 hombres con mediana de edad de 63 años (rango 18-99), la proporción fue bastante superior en las personas mayores de 50 años, la frecuencia del procedimiento en mujeres fue superior con un 57.0% vs. el 43% de los hombres. El número de colonoscopias con resultado normal, fue más frecuente en las personas menores de 50 años (54.8%) contra 45.2% del total de los de 50 años en adelante. Conclusiones. La colonoscopia es un instrumento de gran utilidad al momento de diagnóstico, seguimiento y tratamiento de una gran variedad de patologías gastrointestinales, ya que, a través de esta importante herramienta diagnóstica es posible determinar y descartar otro tipo de patologías que afectan el sistema gastrointestinal.

Perfused murine heart optical transmission spectroscopy using optical catheter and integrating sphere: Effects of ischemia/reperfusion

Tissue transmission optical absorption spectroscopy provides dynamic information on metabolism and function. Murine genetic malleability makes it a major model for heart research. The diminutive size of the mouse heart makes optical transmission studies challenging. Using a perfused murine heart center mounted in an integrating sphere for light collection with a ventricular cavity optical catheter as an internal light source provided an effective method of optical data collection in this model. This approach provided high signal to noise optical spectra which when fit with model spectra provided information on tissue oxygenation and redox state. This technique was applied to the study of cardiac ischemia and ischemia reperfusion which generates extreme heart motion, especially during the ischemic contracture. The integrating sphere reduced motion artifacts associated with a fixed optical pickup and methods were developed to compensate for changes in tissue thickness. During ischemia, rapid decreases in myoglobin oxygenation occurred along with increases in cytochrome reduction levels. Surprisingly, when ischemic contracture occurred, myoglobin remained fully deoxygenated, while the cytochromes became more reduced consistent with a further, and critical, reduction of mitochondrial oxygen tension during ischemic contraction. This optical arrangement is an effective method of monitoring murine heart metabolism.

Optical coherence tomography imaging of cardiac substrates.

Cardiovascular disease is the leading cause of morbidity and mortality in the United States. Knowledge of a patient's heart structure will help to plan procedures, potentially identifying arrhythmia substrates, critical structures to avoid, detect transplant rejection, and reduce ambiguity when interpreting electrograms and functional measurements. Similarly, basic research of numerous cardiac diseases would greatly benefit from structural imaging at cellular scale. For both applications imaging on the scale of a myocyte is needed, which is approximately 100 µm × 10 µm. The use of optical coherence tomography (OCT) as a tool for characterizing cardiac tissue structure and function has been growing in the past two decades. We briefly review OCT principles and highlight important considerations when imaging cardiac muscle. In particular, image penetration, tissue birefringence, and light absorption by blood during in vivo imaging are important factors when imaging the heart with OCT. Within the article, we highlight applications of cardiac OCT imaging including imaging heart tissue structure in small animal models, quantification of myofiber organization, monitoring of radiofrequency ablation (RFA) lesion formation, structure-function analysis enabled by functional extensions of OCT and multimodal analysis and characterizing important substrates within the human heart. The review concludes with a summary and future outlook of OCT imaging the heart, which is promising with progress in optical catheter development, functional extensions of OCT, and real time image processing to enable dynamic imaging and real time tracking during therapeutic procedures.

466Fiber optic contact force catheter efficiency and effectiveness in paroxysmal AF ablation from a large, multi-national, prospective registry (ABLATOR)

466Fiber optic contact force catheter efficiency and effectiveness in paroxysmal AF ablation from a large, multi-national, prospective registry (ABLATOR)

Внутриаортальная баллонная контрпульсация с применением волоконно-оптических катетеров

Внутриаортальная баллонная контрпульсация с применением волоконно-оптических катетеров

29-01: Optical Tissue Interrogation Catheter that Provides Real-Time Monitoring of Catheter-Tissue Contact and RF Lesion Progression using NADH Fluorescence

29-01: Optical Tissue Interrogation Catheter that Provides Real-Time Monitoring of Catheter-Tissue Contact and RF Lesion Progression using NADH Fluorescence

A composite fibre optic catheter for monitoring peristaltic transit of an intra-luminal bead.

A fibre optic motion sensor has been developed for monitoring the proximity and direction of motion of a ferrous bead travelling axial to the sensor. By integrating an array of these sensors into our previously developed fibre optic manometry catheters we demonstrate simultaneous detection of peristaltic muscular activity and the associated motion of ferrous beads through a colonic lumen. This allows the motion of solid content to be temporally and spatially related to pressure variations generated by peristaltic contractions without resorting to videoflouroscopy to track the motion of a radio opaque bolus. The composite catheter has been tested in an in-vitro animal preparation consisting of excised sections of rabbit colon. Cut-away image of the fibre optic motion sensor showing the location of the fibre Bragg gratings and the rare earth magnet.

Assessment of Intramedullary Spinal Pressure in Small Breed Dogs With Thoracolumbar Disk Extrusion Undergoing Hemilaminectomy

To assess intramedullary spinal pressure (IMP) in small breed dogs with thoracolumbar disk extrusion. Prospective cohort study. Small breed dogs (n = 14) with thoracolumbar disk extrusion undergoing hemilaminectomy and healthy chondrodystrophic laboratory dogs (control; n = 3) without spinal disease. Diagnosis was based on clinical and neurological examinations and magnetic resonance imaging (MRI) and was confirmed intraoperatively. A standardized anesthesia protocol and surgical procedure were used to minimize factors that could influence IMP. Intramedullary pressure was measured through a minidurotomy at the site of spinal cord compression using a fiber optic catheter inserted perpendicular to the longitudinal axis of the spinal cord. Measurements were taken after hemilaminectomy and again after removal of extruded disk material. Affected dogs had significantly higher IMP compared to control dogs (P = .008) and IMP decreased significantly post-decompression compared with initial values (P < .001). No correlation was found between IMP and neurologic grade, degree of spinal cord compression on MRI, or signal intensity changes on MRI. Acute thoracolumbar disk extrusion is associated with increased IMP in small breed dogs and surgical decompression results in an immediate decrease of IMP.

Assessment of Intrathecal Pressure in Chondrodystrophic Dogs With Acute Thoracolumbar Disk Disease.

To assess intrathecal pressure (ITP) in chondrodystrophic dogs with thoracolumbar disk extrusion. Prospective cohort study. Group 1: 11 chondrodystrophic dogs with thoracolumbar disk extrusion and present deep pain sensation. Group 2 (control): 3 healthy chondrodystrophic laboratory dogs without spinal disease. Diagnosis was based on neurologic signs, magnetic resonance imaging (MRI) findings, and surgical confirmation. Blood pressure was maintained within physiologic range during anesthesia. A standardized surgical procedure was applied to minimize factors that could influence measurement readings. An extended hemilaminectomy was performed and ITP was measured with a fiber optic catheter. The catheter was inserted in the subarachnoid space 1 spinal segment caudal to the level of herniation and its tip was advanced to the site of compression. Significantly higher ITP occurred in chondrodystrophic dogs with acute thoracolumbar disk disease compared with controls. ITP was not associated with duration of clinical signs, neurologic status, outcome, degree of spinal cord compression, or signal intensity changes as assessed by MRI. Acute thoracolumbar disk disease leads to elevated ITP in chondrodystrophic dogs, which may contribute to increased compression of spinal cord parenchyma.

Supine Position after a Major Spine Surgery: A Bad Position

Introduction Patients undergoing spine surgery by the posterior approach are subjected to excessive and constant pressure on the operative site, because decubitus adopted (dorsal) in most procedures, including lying on his back on the injury held recently. The increased pressure on the wound after surgery may lead to tissue ischemia and this fact may explain why patients operated on by posterior approach have higher rates of pain and infection postoperatively. This prospective, controlled study was designed to demonstrate the excess pressure on the muscle of the wound in patients submitted to surgery in the spine by the posterior approach when they assume supine position. Patients and Methods A total of 22 patients undergoing major surgery in the thoracic and lumbar regions had a fiber optic catheter (Codman ICP Monitoring System, Jonhson and Jonhson) inserted in to the body (right or left) of the paraspinal muscles. The catheter was inserted 3 cm lateral to the incision and 5 cm deep. The pressure was measured and recorded hourly obeying the order of dorsal decubitus, right and left lateral decubitus for 24 hours postoperatively with the patient at bed rest. After this period the catheter was removed. Results Patients had a mean age of 55.9 ± 4.2 years (11 men and 11 women); height of 167.8 ± 2 cm; weight and BMI (body mass index) was 73.0 ± 2 (kg), and 25.3 ± 0.8, respectively. The average abdominal circumference was 93.7 ± 2.7 cm. ANOVA showed a significant difference in mean pressure (24 hours) from the supine position (24.7 ± 2.0 mm Hg) with left or right lateral decubitus (4.92 ± 2.3 mm Hg and 4.77 ± 2.83 mm Hg). There was no significant correlation between weights, sex, BMI, and waist circumference with the pressure of decubitus adopted by the patient, or with the side that the catheter was inserted. Conclusion The supine position adopted in the postoperative period of major spine surgery through the posterior approach can be a factor implicated in postoperative complications. The pressure difference is significant enough to exceed capillary pressure.

Mo2015 Simultaneous Monitoring of Contractile Activity and the Corresponding Transit of Luminal Content Using a Composite Fiber Optic Catheter

Mo2015 Simultaneous Monitoring of Contractile Activity and the Corresponding Transit of Luminal Content Using a Composite Fiber Optic Catheter