Intraballoon Pressure Research Articles

Incidence of cryoballoon expansion dislodgement during pulmonary vein isolation-An underappreciated frequent cause of incomplete isolation.

Cryoballoon ablation for atrial fibrillation (AF) requires adequate contact between the pulmonary vein (PV) antrum and cryoballoon. The surge of intraballoon pressure during the initial phase of ablation may change the balloon's shape and compliance, resulting in balloon dislodgement and loss of PV occlusion. Without continuous monitoring, this phenomenon is often undetected but can be associated with incomplete PV isolation (PVI). Primary cryoablation of AF was performed in 15 patients. PV occlusion status pre- and post-freezing were analyzed with intracardiac echocardiography (ICE) and dielectric imaging-based occlusion tool (DIOT) to calculate the incidence of expansion dislodgement of cryoballoon. A total of 105 cryoablation applications were performed on 57 veins, including three common ostiums of left pulmonary veins. In the evaluation of PV occlusion, both modalities reported consistent results in 86.7% of the assessments. Despite complete PV occlusion before ablation, peri-balloon leak after initiation of freezing was detected by ICE in 5/22 (22.7%) applications and by DIOT in 8/25 (32%) applications. Incidence of expansion dislodgement of the cryoballoon was detected in one-fourth to one-third of cryoablation applications depending on the imaging modality used, which was clinically frequent and significant.

Comparative Outcomes of Anti-Reflux Surgery in Obese Patients with Gastroesophageal Reflux Disease1

IntroductionRoux-en-Y gastric bypass (RYGB) has been the preferred operation for obese patients with gastroesophageal reflux disease (GERD); however, some patients are hesitant to undergo bypass. Obese patients have a multifactorial predisposition to GERD, including lower esophageal sphincter (LES) dysfunction and aberrant pressure gradients across their diaphragmatic crura. Among non-obese patients, anti-reflux surgery (ARS) with hiatal hernia (HH) repair and LES augmentation has shown excellent long-term results. We aimed to determine whether patient satisfaction and GERD recurrence differed between obese and non-obese patients who underwent ARS. MethodsReview of patients who underwent ARS between January 2012 and June 2021 was performed. Perioperative and postoperative characteristics were compared across three BMI groups: BMI < 30 kg/m2, 30 kg/m2 ≤ BMI < 35 kg/m2, and BMI ≥ 35 kg/m2. ResultsFour-hundred thirteen patients were identified, of which 294 (71.1%) had BMI < 30 kg/m2, 87 (21.1%) were 30 kg/m2 ≤ BMI < 35 kg/m2, and 32 (7.7%) had a BMI ≥ 35 kg/m2. Patients with BMI ≥ 35 kg/m2 had higher preoperative manometric and EndoFLIP™ intra-balloon pressure at the LES than those with lower BMIs. This value was increased to a similar level throughout ARS across the three cohorts. Post-operative GERD-specific satisfaction was similar across the three cohorts, as were rates of postoperative reflux and hiatal hernia recurrence on barium swallow; rates of reoperation were low. ConclusionsARS with HH repair and LES augmentation may be appropriate for select patients across a range of BMIs, including those with a BMI ≥ 35 kg/m2 who are hesitant to undergo RYGB.

S3554 Pylorus-Directed Therapy for Gastroparesis Using EsoFLIP

Introduction: Gastroparesis is a complex disease with limited pharmacologic treatment options. Pyloric dysfunction is increasingly recognized as playing an important role in the pathophysiology of the disease which has led to increasing interest in pylorus-directed therapy. The novel endoscopic functional lumen imaging probe (EndoFLIP) and the EsoFLIP catheter allows for dynamic measurement and directed intervention. Case Description/Methods: A 34-year-old man with a past medical history of diabetes mellitus and gastroparesis was admitted after presenting with significant epigastric pain, nausea and vomiting. His initial glucose was 451 mg/dL. The patient was initially treated with an insulin drip, intravenous fluids, and antiemetics including alternating ondansetron, promethazine, and metoclopramide. Despite improvement in the patient's hyperglycemia, the symptoms of nausea and vomiting persisted. The patient underwent esophagogastroduodenoscopy (EGD) with therapeutic intent. The initial endoscopic exam ruled out any mucosal lesions or mechanical obstruction. The EsoFLIP catheter was placed side-by-side the endoscope and under direct visualization was advanced past the pylorus. Proper balloon placement was verified by an hourglass shape of the balloon displayed on the monitor. Measurements were obtained of the cross-sectional area of the pylorus at various balloon volumes starting at 30 ml. The balloon is inflated stepwise at 5 ml intervals and measurements were obtained. The initial pylorus diameter was measured to be 13.7 mm. Care was taken to directly visualize the mucosa during the procedure. The pylorus was dilated up to a diameter of 25 mm. Mucosal rents (tears) were seen after the balloon was deflated. The patient tolerated the procedure well without any immediate complication. His symptoms resolved and he was able to tolerate a regular diet. Discussion: Endoscopic functional lumen imaging probe uses impedance planimetry to calculate pyloric distensibility. Therapeutic dilation using the EsoFLIP system allows real-time and dynamic visualization of the pyloric sphincter with measurements of diameter, cross-sectional area and intra-balloon pressure. This case highlights the therapeutic protentional of EsoFLIP pylorus dilation for refractory gastroparesis. Here we follow a previously described step wise protocol for using the EsoFLIP with the goal of achieving a target pylorus diameter of 25 mm. This protocol has been shown to lead to improvements in symptoms and FLIP metrics as demonstrated in our case.

Quantifying physiologic parameters of the gastroesophageal junction during robotic sleeve gastrectomy and identifying predictors of post-sleeve gastroesophageal reflux disease.

Sleeve gastrectomy is among the most commonly-performed procedures for morbid obesity. However, patients occasionally develop post-sleeve gastroesophageal reflux disease (GERD). Identifying patients most at risk for this complication remains difficult. We aimed to correlate intra-operative physiologic measurements of the lower esophageal sphincter (LES) at the gastroesophageal junction (GEJ) during robotic sleeve gastrectomy in an attempt to identify predictors of post-sleeve GERD symptoms. A retrospective chart review of a prospectively maintained database identified 28 patients in whom robotic sleeve gastrectomy was performed utilizing EndoFLIP™ technology between January and September 2021. Intraoperative LES measurements at the GEJ including cross-sectional area (CSA), distensibility index (DI), intra-balloon pressure, and high-pressure zone (HPZ length) were correlated with post-operative GERD. GEJ CSA, pressure, and DI increased over the course of the surgery (CSA pre-op: 31 (IQR 19.3-39.5) mm2 vs. post-op: 67 (IQR 40.8-95.8) mm2, p < 0.001; pressure: 25.8 (IQR 20.2-33.1) mmHg vs. 31.5 (IQR 28.9-37.0) mmHg, p = 0.007; DI 1.1 (IQR 0.8-1.8) mm2/mmHg vs. 2.0 (IQR 1.2-3.0) mm2/mmHg, p = < 0.001), whereas HPZ length decreased (2.5 (IQR 2.5-3) cm vs. 2.0 (IQR 1.3-2.5) cm, p = 0.022). Twenty-three patients (82.1%) completed a post-operative GERD questionnaire. Fifteen (65.2%) had no GERD symptoms before or after surgery; 5 (21.7%) reported new post-sleeve GERD symptoms; 3 (13.0%) reported exacerbation of pre-existing GERD symptoms. Patients with new or worsening GERD symptoms had higher post-sleeve DIs (3.2 (IQR 1.9-4.5) mm2/mmHg vs. 1.5 (IQR 1.2-2.4) mm2/mmHg, p = 0.024) and lower post-sleeve LES pressures (29.9 (IQR 26.3-32.9) mmHg vs. 35.2 (IQR 31.0-38.0) mmHg, p = 0.023) than those without. An increase in GEJ CSA, pressure, and DI, and a decrease in GEJ length can be expected during robotic sleeve gastrectomy. Patients with new or worsening post-sleeve GERD symptoms have higher post-sleeve DI and lower post-sleeve LES pressure than their asymptomatic counterparts.

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

Erythromycin stimulates phasic gastric contractility as assessed with an isovolumetric intragastric balloon pressure measurement.

A novel technique to assess gastric motility by measuring the pressure in a low-volume intragastric balloon was developed to monitor (disordered) motility. We previously showed that this technique allows measuring pharmacologically induced inhibition of motility. In this study, we assessed whether it is possible to measure pharmacologically induced stimulation of gastric motility using 200mg erythromycin. Erythromycin is a highly effective stimulator of gastric emptying and contractility. After an overnight fast, a nasogastric balloon catheter was introduced in healthy subjects. After inflation with 120ml of air, the catheter was connected to a pressure sensor. Intraballoon pressure was continuously recorded for 4h. After a baseline recording of 2h, 200mg erythromycin was infused intravenously over 20min while the recording continued for 2h. Epigastric symptoms were surveyed on 100-mm visual analogue scales. Motility was quantified from the pressure recording as a gastric balloon motility index. Wilcoxon signed-rank tests were performed. Data are shown as median (interquartile range). Six subjects were enrolled and five completed the procedures (age: 28 (25-29) years, body mass index: 24.0 (23.8-24.5) kgm-2 ). One subject could not tolerate tube placement. Bloating, nausea, and epigastric sensation scores were 0 (0-3), 0 (0-1), and 1 (0-1) mm, respectively. Erythromycin significantly increased the motility index from 0.48 (0.41-0.51) to 0.79 (0.70-0.82) (p=0.03). Gastric motility assessed via pressure measurement in a low-volume intragastric balloon is able to detect pharmacologically stimulated motility in healthy subjects, which further validates this technique.

Using a standardized intra-operative endoflip protocol during fundoplication to identify factors that affect distensibility.

The Endoluminal Functional Lumen Imaging Probe (Endoflip) can be used to provide objective measurements of the gastroesophageal junction during fundoplication, and recent publications have suggested that this device could improve surgical outcomes. However, the impact of operative variables has not been clearly reported. The aim of this study is to determine the effect of these variables on functional lumen imaging probe (FLIP) measurements. Following implementation of a standardized operative FLIP protocol, all data were collected prospectively and entered into a quality database. This database was queried for patients undergoing hiatal hernia repair and fundoplication. The protocol utilized various balloon volumes (30 and 40ml), patient positions (flat and reverse Trendelenburg) and amounts of insufflation (15mmHg pneumoperitoneum and no pneumoperitoneum). Between August 2018 and February 2020, 97 fundoplications were performed by a single surgeon. Multivariable analysis without interactions demonstrated that a 40ml volume fill resulted in significantly higher minimum diameter (Dmin), cross-sectional area (CSA), intra-balloon pressure (IBP) and distensibility index (DI) compared to a 30ml volume fill (p < 0.001). While reverse Trendelenburg positioning resulted in a significantly higher Dmin, IBP and CSA compared to the flat position (all p < 0.05), there was little impact of positioning on DI. Lastly, pneumoperitoneum significantly increased IBP (p < 0.001) but did not affect Dmin (p = 0.697) or CSA (p = 0.757), which resulted in a significant decrease in DI (p < 0.001) when compared to measurements without pneumoperitoneum. Multivariable analysis allowing for interactions demonstrated significant two-way interactions between balloon volume and pneumoperitoneum (p = 0.047), as well as patient position and pneumoperitoneum (p < 0.001). Surgeons should consider balloon volume and the presence or absence of pneumoperitoneum when interpreting distensibility during or after fundoplication. Additionally, we suggest a formal standardized protocol for FLIP measurements to utilize a 40ml volume fill in reverse Trendelenburg without pneumoperitoneum.

Esophageal Functional Lumen Imaging Probe (FLIP): How Can FLIP Enhance Your Clinical Practice?

Recent innovations in esophageal diagnostic testing have enhanced gastroenterology clinical practice by facilitating more nuanced and advanced evaluation of esophageal symptoms. Among these pivotal advances is the FDA-approved functional lumen imaging probe (FLIP), which utilizes impedance planimetry via volumetric distension of a catheter-mounted balloon at the time of sedated upper endoscopy, to acquire esophageal dimensions and pressures. In real time, FLIP can display cross-sectional areas (CSA) and distensibility indices (ratios of CSA to intra-balloon pressures) throughout the esophagus, most notably at the esophagogastric junction, as well as secondary peristaltic esophageal body contractile patterns. As the use of FLIP has progressively spread and permeated into the practice of clinical gastroenterology since its introduction, increasing data on and experiences with its applications have accumulated to guide its utility in clinical practice. In this current review developed for gastroenterologists and foregut surgeons across clinical practice, we provide an introduction to FLIP technology and metrics and discuss the clinical scenarios in which performance of or referral for FLIP may be helpful in the evaluation and management of patients with commonly encountered esophageal symptoms and disorders. Specifically, we discuss the potential applications and limitations of FLIP as a complementary diagnostic modality in patients with non-obstructive dysphagia, established or suspected achalasia spectrum disorders, eosinophilic esophagitis, gastroesophageal reflux disease and those undergoing esophageal surgery.

Impact of gastric per-oral endoscopic myotomy on static and dynamic pyloric function in gastroparesis patients.

Functional Lumen Imaging Probe (EndoFLIP) tests typically measure static pyloric parameters, but the pylorus exhibits phasic variations on manometry. Dynamic changes in pyloric function have not been quantified using EndoFLIP, and the impact of Gastric Per-Oral Endoscopic Myotomy (G-POEM) on static and dynamic pyloric activity in gastroparesis is unknown. EndoFLIP balloon inflation to 30, 40, and 50mL was performed to measure mean, maximum, and minimum values and variability in pyloric diameter and distensibility before and after G-POEM in 20 patients with refractory gastroparesis. The impact of phasic contractions on these pyloric measures was compared. G-POEM increased mean (P<.0001) and maximum (P=.0002) pyloric diameters and mean (P=.02) and maximum (P=.02) pyloric distensibility on 50mL EndoFLIP inflation but not intraballoon pressures or minimum diameters or distensibility. Temporal variability of pyloric diameter (P=.02) and distensibility (P=.02) also increased after G-POEM. Phasic coupled contractions propagating from the antrum through the pylorus were observed in 37.5% of recordings; other phasic activity including isolated pyloric contractions were seen in 23.3%. Variability of pyloric diameter and distensibility tended to be higher during recordings with phasic activity. Some pyloric responses to G-POEM were influenced by age, gastroparesis etiology, gastric emptying, and prior botulinum toxin injection. Pyloric activity exhibits dynamic changes on EndoFLIP testing in gastroparesis. G-POEM increases maximal but not minimal diameter and distensibility with increased variations, suggesting this therapy enhances pyloric opening but may not impair pyloric closure. Phasic pyloric contractions contribute to variations in pyloric activity.

Distal pressure monitoring and titration with percent balloon volume: feasible management of partial resuscitative endovascular balloon occlusion of the aorta (P-REBOA).

Resuscitative endovascular balloon occlusion of the aorta (REBOA) increases proximal arterial pressure, but may also induce life-threatening distal ischemia. Partial REBOA (P-REBOA) is thought to mitigate distal ischemia during aortic occlusion. However, feasible indicators of the degree of P-REBOA remain inconsistent. We hypothesised percent balloon volume could be a substitute for pressure measurements of gradients during P- REBOA. This study aimed to compare balloon volume and arterial pressure gradient, and analysed with intra-balloon pressure and balloon shape. Proximal (carotid) and distal (femoral) arterial pressures were recorded and a 7-Fr REBOA catheter was placed in four swine. Total REBOA was defined as a cessation of distal pulse pressure and maximum balloon volume was documented. The balloon volume was titrated by 20% increments of maximum capacity to adjust the degree of P-REBOA. The distal/proximal arterial pressure gradient and the intra-balloon pressures were also recorded. The changes in shape and the cross-sectional area of the balloon were evaluated with computed tomography (CT) images. The proximal mean arterial pressure (MAP) plateaued after 60% balloon volume; meanwhile, distal pulse pressure was still left. The balloon pressure was traced with proximal MAP before contact with aortic wall. The balloon shape changed unevenly from "cone" to "spindle" shape, although the balloon cross-sectional area of the mid-segment linearly increased. Monitoring distal pressure and titrating percent balloon volume is feasible to manage P-REBOA. In this experiment, 60% balloon volume was enough inflation to elevate central pressure allowing distal perfusion. The intra-balloon pressure was not reliable due to the strong influence of proximal MAP and uneven change of the balloon shape.

Defining degree of aortic occlusion for partial-REBOA: A computed tomography study on large animals

IntroductionPartial resuscitative endovascular balloon occlusion of the aorta (P-REBOA) is a modified REBOA technique designed to help ameliorate ischemia-reperfusion injury. The balloon is partially deflated, allowing a proportion of aortic flow distal to the balloon. The aim of this study is to use an ovine model of haemorrhagic shock to correlate the degree of occlusion to several hemodynamic indices. Materials and methodsSix sheep weighing 35–46 kg underwent a controlled venous haemorrhage inside a CT scanner until the systolic arterial pressure (AP) dropped to <90 mmHg. A balloon positioned in an aortic zone I was incrementally filled with 1 mL of saline, with serial measurement of the proximal (carotid artery) and distal (femoral artery) mean APs (MAP) and intra-balloon pressure (IBP), along with CT imaging, following each inflation, until full occlusion was achieved. ResultsA diameter of the aorta at zone I was 16.0 (15.7–17.2) mm, with a cross-sectional area of 212 (194–233) mm2. Median volume of saline injected into the balloon until total occlusion was 7.0 (6.3–8.5) mL. During gradual balloon inflation, proximal MAP increased and distal MAP decreased proportionate to the degree of occlusion, in a linear fashion (proximal: r2 = 0.85, p < 0.001; distal: r2 = 0.95, p < 0.001). The femoral/carotid (F/C) pressure gradient also demonstrated a linear trend (r2 = 0.90, p < 0.001). The relationship between percentage occlusion and IBP was sigmoid. MAP values became significantly different at 40-49% occlusion and more (p < 0.01). Furthermore, a drop in the distal pulse pressure from 7.0 (5.5–16.5) to 2.0 (1.5–5.0) mmHg was observed at 80% occlusion. All animals had femoral pulse pressure <5 mmHg at 80% of occlusion and more, which also coincided with the observed loss of pulsatility of the femoral wave-form. ConclusionSerial CT angiography at an ovine model of haemorrhagic shock demonstrates a correlation between the femoral MAP, F/C pressure gradient and degree of zone I P-REBOA during the staged partial aortic occlusion. These parameters should be considered potential parameters to define the degree of P-REBOA during animal research and clinical practice.

High-Pressure Balloon-Assisted Stretching of the Coracohumeral Ligament to Determine the Optimal Stretching Positions: A Cadaveric Study

BackgroundThe coracohumeral ligament (CHL) is a thick capsular structure and markedly thickened when affected by adhesive capsulitis. Therapeutic stretching is the most commonly applied treatment for adhesive capsulitis, but optimal stretching postures for maximal therapeutic effects on the CHL have not been fully investigated. ObjectiveTo investigate the most effective stretching direction for the CHL by measuring the stretching intensity in 5 different directions and to determine whether the stretching intervention resulted in loosening of the ligament by comparing the changes of CHL tightness before and after stretching. DesignBiomechanical cadaver study. SettingAcademic institution cadaver laboratory. ParticipantsNine fresh frozen cadaveric shoulders. MethodsA high-pressure balloon catheter inserted under the CHL and intraballoon pressure was measured, to evaluate CHL tightness without ligament damage as well as to augment and monitor stretching intensity. To find the optimal stretching direction, the glenohumeral joint was stretched from the neutral position into 5 directions sequentially under pressure-monitoring: flexion, extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD] directions. Main Outcome MeasurementsCHL tightness was determined by a surrogate parameter, the additional pressure created by the overlying CHL. The pressure increase (ΔPstr) by a specific directional stretch was considered as the stretching intensity. ResultsΔPstr by the 5 directions were mean (standard deviation) values of 0.03 ± 0.07 atm, 0.87 ± 1.31 atm, 1.13 ± 1.36 atm, 1.49 ± 1.32 atm, and 2.10 ± 1.70 atm, respectively, revealing the highest ΔPstr by the EX+ER+AD stretch (P < .05). The balloon pressure by the overlying CHL was decreased from 0.45 ± 0.35 atm to 0.18 ± 0.14 atm (P = .012) before and after the stretching manipulation. ConclusionsEX+ER+AD of the glenohumeral joint resulted in the greatest increase in balloon pressure, implying that it could be the most effective stretching direction. A series of stretching manipulations assisted with an underlying pressure balloon were capable of decreasing CHL tightness. With further development and modification, high-pressure balloon-assisted stretching can be a potential therapeutic option to release tight CHL, including the advantage of augmenting and monitoring stretching intensity. Level of EvidenceII

Endotracheal tube cuff inflation with and without a pressure gauge to minimise sevoflurane pollution during intermittent positive pressure ventilation

Editor,Possible health hazards from exposure to trace concentrations of inhalational anaesthetics cannot yet be definitively excluded.1 We have previously reported that the concentrations of the commonly used volatile anaesthetic sevoflurane were significantly higher in the proximity of the intubate

Feasibility of esophagogastric junction distensibility measurement during Nissen fundoplication

Increased esophagogastric junction distensibility has been implicated in the development of gastroesophageal reflux disease (GERD). Previous authors have demonstrated a reduction in distensibility following anti-reflux surgery, but the changes during the operation are not clear. Our study aimed to ascertain the feasibility of measuring intraoperative distensibility changes and to assess if this would have potential to modify the operation. Seventeen patients with GERD were managed in a standardized manner consisting of preoperative assessment with symptom scoring, endoscopy, 24 hours pH studies, and manometry. Patients then underwent laparoscopic Nissen fundoplication with intraoperative distensibility measurement using an EndoFLIP EF-325 functional luminal imaging probe (Crospon Ltd, Galway, Ireland). This device utilizes impedance planimetry technology to measure cross-sectional area and distensibility within a balloon-tipped catheter. This is inflated at the esophagogastric junction to fixed distension volumes. Thirty-second median cross-sectional area and intraballoon pressure measurements were recorded at 30 and 40 mL balloon distensions. Measurement time points were initially after induction of anesthesia, after pneumoperitoneum, after hiatal mobilization, after hiatal repair, after fundoplication, and finally pre-extubation. Postoperatively, patients continued on protocol and were discharged after a two-night stay tolerating a sloppy diet. Patients with a hiatus hernia on high-resolution manometry had a significantly higher initial esophagogastric junction distensibility index (DI) than those without. Hiatus repair and fundoplication resulted in a significant overall reduction in the median DI from the initial to final recordings (30 mL balloon distension reduction of 3.26 mm(2) /mmHg (P = 0.0087), 40 mL balloon distension reduction of 2.39 mm(2) /mmHg [P = 0.0039]). There was also a significant reduction in the DI after pneumoperitoneum, hiatus repair, and fundoplication at 40 mL balloon distension. Two individual cases in the series highlight the utility of the system in potentially changing the operation. After fundoplication, patient 7 recorded a DI of 0.47 mm(2) /mmHg, the lowest in our series, and subsequently required reoperation because of significant symptoms of dysphagia. Patient 12 had a fundoplication that appeared visually too tight and was converted intraoperatively to a Lind 270° wrap resulting in a change in the DI from 0.65 to 0.89 mm(2) /mmHg. Laparoscopic Nissen fundoplication results in a significant reduction in the distensibility of the esophagogastric junction. The EndoFLIP system is able to demonstrate significant changes during the operation and may help guide intraoperative modification. Larger multicenter studies with long-term follow up would be beneficial to develop a target range of distensibility associated with good outcome.

A Model of Drug Deposition Within Artery Walls

A Model of Drug Deposition Within Artery Walls

Influence of nitric oxide synthase inhibition on the motility and sensitivity of distal colon in man

Alterations of nitrergic innervation have been implicated in the pathophysiology of motor-sensory abnormalities of post infectious functional dyspepsia and could be involved in the pathophysiology of post infectious irritable bowel syndrome. The role of nitrergic neurons in the control of distal colonic sensorimotor function in man is not known. The aim of this study is to evaluate the motility and sensitivity of distal colon in healthy subjects before and after a nitric oxide synthase inhibitor (L-NMMA). A 700-mL balloon connected with a barostat-manometry assembly was placed in the descending colon of 10 healthy subjects and distension (4 mmHg/2 min) was performed. Intra-balloon pressure was then set at minimal distending pressure + 2 mmHg for 30 min, placebo or L-NMMA (8 mg kg(-1) h(-1)) was administered i.v. in double-blind, randomized, cross-over design and distensions were repeated. Placebo and L-NMMA did not influence colonic compliance, motility index, and tone. Placebo did not affect thresholds for first perception and discomfort and the areas under the pressure-perception curve. L-NMMA did not alter thresholds for first perception, but significantly decreased the pressure thresholds for discomfort (P = 0.008) and increased the areas under the pressure-perception score (P = 0.01). In man, inhibition of nitric oxide synthase sensitizes the distal colon to distension. Impaired nitrergic innervation is a mechanism that may be involved in the pathogenesis of hypersensitivity to colonic distension.

New measures of upper esophageal sphincter distensibility and opening patterns during swallowing in healthy subjects using EndoFLIP®

This paper aims to measure upper esophageal sphincter (UES) distensibility and extent and duration of UES opening during swallowing in healthy subjects using EndoFLIP(®). Fourteen healthy subjects (20-50 years) were recruited. An EndoFLIP(®) probe was passed trans-orally and the probe balloon was positioned across the UES. Two 20-mL ramp distensions were completed and UES cross-sectional area (CSA) and intra-balloon pressure (IBP) were evaluated. At 12-mL balloon volume, subjects completed dry, 5- and 10-mL liquid swallows and extent (mm) and duration (s) of UES opening and minimum IBP (mmHg) were analyzed across swallows. Thirteen subjects completed the study protocol. A significant change in UES CSA (P < .001) and IBP (P < .000) was observed during 20-mL distension. UES CSA increased up to 10-mL distension (P < .001), from which point IBP raised significantly (P = 0.004). There were significant changes in UES diameter (mm) (P < .000) and minimum IBP (mmHg) (P < .000) during swallowing events. Resting UES diameter (4.9 mm; IQR 0.02) and minimum IBP (18.8 mmHg; IQR 2.64) changed significantly during dry (9.6 mm; IQR 1.3: P < .001) (3.6 mmHg; IQR 4.1: P = 0.002); 5 mL (8.61 mm; IQR 2.7: P < .001) (4.8 mmHg; IQR 5.7: P < .001) and 10-mL swallows (8.3 mm; IQR 1.6: P < 0.001) (3 mmHg; 4.6: P < .001). Median duration of UES opening was 0.5 s across dry and liquid swallows (P = 0.91). Color contour plots of EndoFLIP(®) data capture novel information regarding pharyngo-esophageal events during swallowing. Authors obtained three different types of quantitative data (CSA, IBP, and timing) regarding UES distensibility and UES opening patterns during swallowing in healthy adults using only one device (EndoFLIP(®)). This new measure of swallowing offers fresh information regarding UES dynamics which may ultimately improve patient care.

Intraoperative assessment of esophagogastric junction distensibility during per oral endoscopic myotomy (POEM) for esophageal motility disorders

Per oral endoscopic myotomy (POEM) is a novel treatment for esophageal motility disorders such as achalasia. To date, the extent of the myotomy has been determined based on the subjective assessment of the endoscopist. We hypothesized that the real-time measurement of esophagogastric junction (EGJ) distensibility using a novel functional lumen-imaging probe would enable objective evaluation of POEM. Patients diagnosed with achalasia disorders electively underwent POEM. Using impedance planimetry with a transorally inserted functional lumen-imaging probe (EndoFLIP), cross-sectional areas (CSA) and distensibilities at the EGJ were measured intraoperatively immediately before and after the transoral myotomy (n = 4). All patients completed their 6-month follow-up and two patients had repeat distensibility tests at this time. Four healthy volunteers served as a control group. POEM was successfully performed in all patients (4/4). Premyotomy measurements (40-ml fill mode) showed a median diameter of 6.5 mm (range = 5.2-7.9 mm) at the narrowest location of the EGJ and was 10.1 mm (7.3-13.2 mm) following POEM. CSA increased from 41.5 mm(2) (20-49 mm(2)) to 86 mm(2) (41-137 mm(2)) at a similar median intraballoon pressure (40.3 vs. 38.6 mmHg). The increased EGJ distensibility (DI, 1.0 vs. 2.4 mm(2)/mmHg) was comparable to that of healthy volunteers (2.7 mm(2)/mmHg). Functional lumen distensibility measures show that POEM can result in an immediate correction of the nonrelaxing lower esophageal sphincter, which appears similar to that of healthy controls. Intraoperative EGJ profiling may be an important tool to objectively guide the needed extent and completeness of the myotomy during POEM.

Assessment of annular distensibility in the aortic valve

OBJECTIVES The recent introduction of transcatheter aortic heart valves into clinical practice has driven the need to develop methodologies to size such valves without access to the annulus in the manner hitherto possible with open heart surgery. To date, sizing has largely been done according to manufacturer-supplied guidelines based on transoesophageal echocardiography or multidetector computed tomography. We sought to examine how the diameter of the aortic valve annulus stretches under typical pressures encountered in normal and diseased states. In particular, we sought to measure how the area-derived diameter, Dcsa, i.e. the diameter derived from a cross-sectional area, varies with distending pressure. METHODS We conducted testing on 14 explanted pig hearts. Placing each heart in a 37 °C bath, an EndoFLIP EF-325 catheter (Crospon, Galway, Ireland) was introduced into the aortic valve transapically. The catheter allows intra-balloon pressure and up to 16 area-derived diameters to be measured simultaneously, thus permitting the shape of a lumen to be observed. By dividing the minimum area-derived diameter by distending pressure, a measure of distensibility (mm/mmHg) could be determined. Once the balloon was centred, balloon pressure was ramped between 100 and 200 mmHg, and the area-derived diameter was calculated at each pressure. RESULTS Between 100 and 200 mmHg, the mean (SD) increase in diameter was found to be 3.0 (1.5) mm. Distensibility in the different hearts ranged from 0 to 0.05 mm/mmHg. In some cases, the diameter change over the pressure range was negligible, whereas in one case, the diameter change over the range was 5 mm. Whereas different nominal values of diameter are to be expected, a significant variation in the degree of distensibility was observed. CONCLUSIONS Distensibility of the aortic valve annulus is highly variable. Measurement of this parameter in addition to nominal annulus diameter may suggest occasions where a larger transcatheter aortic-valve implantation valve than would be suggested by annulus diameter measurement alone, could be deployed safely with an objective of reducing regurgitation where the annulus is sufficiently distensible.

A new evaluation of the upper esophageal sphincter using the functional lumen imaging probe: a preliminary report

Objective and reliable evaluation of upper esophageal sphincter (UES) opening during swallowing based on videofluoroscopy and pharyngeal manometry challenges dysphagia clinicians. The functional lumen imaging probe (FLIP) is a portable tool based on impedance planimetry originally designed to measure esophogastric junction compliance. It is hypothesized that FLIP can evaluate UES distensibility, and can provide UES diameter and pressure measurements at rest, during swallowing, and during voluntary maneuvers. Eleven healthy adult subjects consented to FLIP evaluation. The probe was inserted transorally, and the balloon was positioned across the UES. Two 20-mL ramp distensions were completed. Changes in UES diameter and intraballoon pressure were measured during dry and 5-mL liquid swallows, and during voluntary swallow postures and maneuvers employed in clinical practice. The protocol was completed by 10 of 11 healthy subjects. Mean intraballoon pressure increased throughout 5-mL (5.8 mmHg; -4.5-18.6 mmHg), 10-mL (8.7 mmHg; 2.3-28.5 mmHg), 15-mL (17.3 mmHg; 9.5-34.8 mmHg), and 20-mL (31.2 mmHg; 16-46.3 mmHg) balloon volumes. Mean resting UES diameter (4.9 mm) increased during dry swallows (9.2 mm) and 5-mL liquid swallows (7.7 mm). Mean UES diameter increased during 5-mL liquid swallows with head turn to right (8.1 mm) and left (8.3 mm), chin tuck (8.4 mm), effortful swallow (8.5 mm), Mendelsohn maneuver (8.1 mm), and supraglottic swallow (7.8 mm). FLIP was safely inserted and distended in the UES, and provided useful quantitative data regarding UES distensibility and UES diameter changes during swallowing maneuvers. Further research is being conducted to explore the role of FLIP in UES evaluation.