High Residual Pressure Research Articles

Five-Year Outcomes of Measured and Predicted Prosthesis-Patient Mismatch following Transcatheter Aortic Valve Implantation

BackgroundData on the long-term outcomes of prosthesis-patient mismatch (PPM) after transcatheter aortic valve implantation (TAVI) remain controversial. ObjectivesThe aim of this study was to investigate the incidence and clinical outcomes of measured PPM (PPMM) and predicted PPM (PPMP) in patients undergoing TAVI. MethodsThis is a retrospective analysis of 3,016 patients who underwent TAVI at a large Healthcare System between 2012 and 2021. Effective orifice area indexed to body surface area (EOAi) was measured at discharge using the continuity equation. EOAi was predicted according to the published predictive tables for each model and size of the valve. Primary endpoint was 5-year survival rate. ResultsMean age was 80 years and 55.6% were male. The mean STS risk score was 4.66%. 74.9% of patients received a BEV and 25.1% received a SEV. The incidence of severe PPM was markedly lower when defined by predicted vs. measured EOAi (0.8% vs. 6.3%, P < 0.001) and when assessed in SEV vs. BEV (5.3% vs. 6.6%, p= 0.02). Neither severe PPMp nor severe PPMM was associated with 5-year mortality (HR=1.26, 95% CI= 0.96-1.66, p=0.095; HR=1.03, 95% CI= 0.42-2.49, p=0.954, respectively), irrespective of the presence of high residual pressure gradient. Neither BEV nor SEV was associated with an increased 5-year mortality, irrespective of PPM definition or severity. ConclusionsIn this large healthcare system analysis, neither severe PPMP nor severe PPMM was associated with five-year all-cause mortality. There was no difference between BEV and SEV in terms of mortality, irrespective of the definition or severity of PPM.

Mechanism and application of gas phase trapping by spontaneous imbibition

For fractured gas reservoirs with strong water drive, gas phase trapping affects the gas recovery significantly. The recovery may be less than 50% for some reservoirs while it is only 12% for Beaver River gas field. The gas phase trapping mechanism has been revealed by the results of depletion experimental test. The residual pressure of the trapped gas is as high as 11.75 MPa with a 12.8 cm imbibition layer resulting in gas recovery deceased 49.5% compared with that without imbibition layer. A mathematical model is built to calculate the imbibition thickness based on capillary pressure and relative permeability of the matrix. The gas phase trapping are analyzed by two representative wells in Weiyuan gas field, the intermittent production reinforces the imbibition thickness and result in gas trapped in the matrix block with high residual pressure for the low performace gas wells, the extremely low gas recovery can be explained more rationally. That lays a foundation of improving the gas recovery for fractured reservoirs.

Surgical versus transcatheter aortic valve replacement: Impact of patient-prosthesis mismatch on outcomes.

The hemodynamics of most prosthetic valves are often inferior to that of the normal native valve, and a significant proportion of patients undergoing surgical (SAVR) or transcatheter aortic valve replacement (TAVR) have high residual transaortic pressure gradients due to prosthesis-patient mismatch (PPM). As the experience with TAVR has increased and long-term outcomes are reported, a close look at the PPM literature is required in light of new evidence. For this review, we searched the Embase, Medline, and Cochrane databases from 2000 to 2022. Articles reporting PPM as an outcome following aortic valve replacements were identified and reviewed. The impact of PPM on clinical outcomes in aortic valve replacement has not been clear as multiple studies failed to report PPM incidence. However, the PPM outcomes after SAVR vary more widely than after TAVR, ranging from 8% to 80% in SAVR and from 24% to 35% in TAVR. Incidence of severe PPM following redo SAVR ranges from 2% to 9% and following valve-in-valve TAVR is from 14% to 33%, however, while PPM is higher in valve-in-valve TAVR, patients had better survival rates. The gap between valve performance and clinical outcomes in SAVR and TAVR could be reduced by carefully selecting patients for either treatment option. Understanding predictors of PPM can add to the safety, effectiveness, and increased survival benefit of both SAVR and TAVR.

Influence of blade number on performance of multistage hydraulic turbine in turbine mode

AbstractCompared with the traditional reverse multistage pump as hydraulic turbine, hydraulic turbine in turbine mode (T‐type turbine) with low specific speed has higher single‐stage energy head, which can effectively reduce stages and increase the stability when it is used to recycle high residual pressure liquid. Blade number of runner is an important design parameter, which has great influence on the performance of T‐type hydraulic turbine and need to be further studied. Therefore, two‐stage T‐type turbine models with different blade numbers are established through numerical simulation. Then, the accuracy of numerical simulation is verified by test. Finally, the performance and pressure fluctuating characteristics of turbine with different blade numbers are obtained. The results show that: (a) Taking same blade numbers in both stages (traditional design method), the turbine efficiency can be higher with the blade number of primary runner and secondary runner are 14, but resulting the superposition of pulsation in secondary runner; (b) Taking different blade numbers in both stages, respectively, the superposition of pulsation can be effectively avoided, which also leads to the increase in efficiency, and up to 81.169%; (c) The method of using different number of blades in different stages can replace the traditional design method and effectively improve the hydraulic performance of T‐type hydraulic turbine.

An enhanced design method for 3D contact surfaces on shaft–hub connections joined through lateral extrusion

A recently developed design method for circular shaft–hub connections joined using the cold-forming process of lateral extrusion allows predefined contact stress distributions to be generated on the contact surface by gradient-less shape optimization. Using contact stress results from elastic-plastic finite-element analyses and simplified rules derived from cylindrical interference fits, the contact surface of the hub is adapted locally to the shape of the formed shaft in an iterative process. In this paper, the design method is expanded from circular to non-circular profile shapes based on complex cycloids to create optimized, polygon shaft–hub connections, minimizing sliding and fretting fatigue under dynamic loads. To enable local adaptation of non-circular contact surfaces, we introduce a suitable definition for 3D profiles, which allows simultaneous variation of the profile mean radius and eccentricity. This allows designers to create contact surface designs with complex shapes that conform to predefined contact stress distributions along the connection length. The feasibility of the method is finally demonstrated by undertaking a design adaptation study on a sample non-circular shaft–hub connection and comparing the results to the initial design. While the contact stress results for the adapted design agree very well with the specified target curves, an overall more uniform stress distribution in the hub is also achieved. Due to its combined form and friction-fit properties with high residual contact pressure, the connection is predestined for use in novel electric and hybrid drive applications, where lightweight design as well as high power density and rotational speeds are required.

Sampling reflex: pathogenic role in functional defecation disorder.

The sampling reflex is necessary to begin defecation or flatulence. It consists of a simultaneous rectoanal inhibitory reflex (RAIR) mediated by relaxation of the internal anal sphincter and rectoanal excitatory reflex (RAER) mediated by contraction of the external anal sphincter. The aim of this study was to evaluate the sampling reflex in patients with functional defecation disorder (FDD). A prospective cohort study was conducted on 58 obstructed defecation syndrome (ODS) patients with FDD. All 58 patients and 20 controls were evaluated with anorectal manometry to study the sampling reflex. Quantitative RAIR (total duration of reflex; maximal amplitude of relaxation; residual pressure at the lowest point of the RAIR) and RAER data (maximal amplitude of contraction; duration) were obtained. The straining test on manometry was considered positive for FDD if there was a muscle contraction/lack of relaxation or an insufficient pressure gradient for the passage of feces. Defecography was performed on all the patients with assessment of the anorectal angle and persistence or increase of puborectalis indentation. Fifty (86.2%) FDD patients had an altered sampling reflex, showing incomplete/short duration of RAIR and excessive contraction/duration of RAER. More specifically, there was a correlation between a positive straining test and a short total duration of RAIR (ρ 0.92) as well as with excessive duration of RAER (ρ 0.89). There was also a correlation between lack of muscle relaxation on defecography and short total duration of RAIR ((ρ 0.79) and between lack of muscle relaxation on defecography and excessive duration of RAER (ρ 0.83). Altered maximal amplitude relaxation had the highest sensitivity in detecting impairment of RAIR (87.9) while maximal amplitude contraction had the highest sensitivity in detecting impairment of RAER (89.6). High residual pressure at the lowest point of RAIR had the highest specificity in detecting impairment of RAIR (80.0) while RAER duration had the highest specificity in detecting impairment of RAER (77.7). The sampling reflex is impaired in patients with FDD. This finding provides an important insight into the pathogenesis of obstructed functional defecation.

Comparison of catheter-directed thrombolysis and anticoagulation in intermediate-risk pulmonary embolism: A retrospective analysis

BACKGROUND AND OBJECTIVES: The selection of escalation of care strategies for the treatment of intermediate-risk pulmonary embolism (PE) is a matter of debate. Here, we aimed to assess the features of our population treated either with anticoagulation (AC) alone or catheter-directed thrombolysis (CDT). We also sought to identify a relationship between high residual systolic pulmonary artery pressure (sPAP) and demographic and clinical variables. PATIENTS AND METHODS: The retrospective data of 30 intermediate-high-risk PE patients were analyzed. CDT was used in 14 (46.7%) cases. Enoxaparin (b. i. d) injections were administered in the AC group. In the CDT group, patients received 5 mg bolus dose of alteplase followed by 1 mg/h infusion for 24 h. Estimated sPAP at presentation and discharge was recorded. A value equal to or greater than 40 mmHg in the latter was accepted as a significant rise. RESULTS: The patients in the CDT group had a lower HAS-BLED score (2 [0–3] vs. 1 [0–3], P = 0.03). Although initial sPAP values were comparable among treatment arms, sPAP at discharge was significantly lower in the CDT group (mmHg, 42 ± 11.2 vs. 33.6 ± 9.7, P = 0.04). The reduction in sPAP at discharge was also significantly higher in this group. The degree of reduction in sPAP was considerably correlated with baseline sPAP (r: 63.2, P CONCLUSION: CDT was preferred over AC when lower bleeding risk was anticipated for intermediate-high-risk PE patients in our sample population. Eventually, CDT provided lower discharge sPAP levels and a greater reduction in sPAP. However, the factors associated with high sPAP at discharge were only high baseline sPAP measurement and HAS-BLED score.

Long-term outcome of percutaneous balloon aortic valvuloplasty for children with congenital aortic valve stenosis

Objective: To assess the efficacy and long-term outcome of percutaneous balloon aortic valvuloplasty (PBAV) for children with congenital aortic stenosis (CAS) and to explore risk factors for significant aortic regurgitation (AR) and reintervention after PBAV during follow up. Methods: This was a retrospective study. Children (≤18 years old) with CAS, who underwent PBAV in Guangdong Provincial Hospital from January 2004 to December 2018, were included in this study. Demographic, preoperative transthoracic echocardiography (TTE) and surgical data were collected. Postoperative complications were closely observed, and the patients were followed up at 1, 6, 12 months after the operation, and then at one year interval thereafter. Endpoint events included significant AR and reintervention. Reintervention was defined as any intervention that needed to be performed on the valve for various reasons, including re-PBAV, surgical valvuloplasty and valve replacement. Significant AR was defined as AR grade≥3 by TTE criteria. The results of the last TTE examination before the end of the study were collected. The Kaplan-Meier curve for long-term AR-free and intervention-free survival was plotted. Cox regression model was used to further analyze the risk factors for significant AR and reintervention after PBAV in CAS patients. Results: A total of 55 patients were enrolled in this study, and the age was 4.6(1.6, 6.5) years, with 37(67.3%) males. The peak systolic valve gradient fell from (80.3±30.6)mmHg to (38.5±18.5)mmHg(P<0.001, 1 mmHg=0.133 kPa). Surgical success rate was 89% (49/55). Acute post-PBAV AR occurred in 18 patients, including 3 patients with RA≥3 grade. In-hospital complications occurred in 6 patients (2 deaths, 2 cases of transient arrhythmia, and 2 cases of femoral artery embolization). Fifty patients accomplished the follow-up and the follow-up time was 6.2(3.4, 8.5) years. Significant AR was found in 20 patients. Significant AR-free survival rate was 53% at 5 years and 19% at 10 years. Reintervention was performed in 11 patients (4 with valvuloplasty and 7 with valve replacement), and the 5-year and 10-year intervention-free survival rates were 87% and 62%, respectively. Multivariate Cox regression analysis showed that acute post-PBAV AR was a risk factor for long-term significant AR (HR=2.398, 95%CI 1.007-5.712, P=0.048). Post-PBAV residual pressure gradient ≥ 35 mmHg (HR=4.747, 95%CI 1.116-19.329, P=0.030)and acute post-PBAV AR (HR=5.104, 95%CI 1.083-24.065, P=0.039)were risk factors for re-intervention. Conclusions: PBAV is safe and effective in the treatment of CAS in children, but attention should be paid on significant AR post procedure. Acute post-PBAV AR is a risk factor for re-intervention and significant AR post PBAV, and high post-PBAV residual pressure gradient is a risk factor for re-intervention.

A new occurrence of retrogressed eclogite from the Sanbagawa belt of southwest Japan and its significance

AbstractThe present paper reports, for the first time, the occurrence of an omphacite‐bearing mafic schist from the Asemi‐gawa region of the Sanbagawa belt (southwest Japan). The mafic schist occurs as thin layers within pelitic schist of the albite–biotite zone. Omphacite in the mafic schist only occurs as inclusions in garnet, and albite is the major Na phase in the matrix, suggesting that the mafic schist represents highly retrogressed eclogite. Garnet grains in the sample show prograde‐type compositional zoning with no textural or compositional break, and contain mineral inclusions of omphacite, quartz, glaucophane, barroisite/hornblende, epidote and titanite. In addition to the petrographic observations, Raman spectroscopy and focused ion beam system–transmission electron microscope analyses were used for identification of omphacite in the sample. The omphacite in the sample shows a strong Raman peak at 678 cm−1, and concomitant Raman peaks are all consistent with those of the reference omphacite Raman spectrum. The selected area electron diffraction pattern of the omphacite is compatible with the common P2/n omphacite structure. Quartz inclusions in the mafic schist preserve high residual pressure values of Δω1 &gt; 8.5 cm−1, corresponding to the eclogite facies conditions. The combination of Raman geothermobarometries and garnet–clinopyroxene geothermometry gives peak pressure–temperature (P–T) conditions of 1.7–2.0 GPa and 440–540 °C for the mafic schist. The peak P–T values are comparable to those of the schistose eclogitic rocks in other Sanbagawa eclogite units of Shikoku. These findings along with previous age constraints suggest that most of the Sanbagawa schistose eclogites and associated metasedimentary rocks share similar simple P–T histories along the Late Cretaceous subduction zone.

Tu1246 – High Residual Upper Esophageal Sphincter Pressure (UESP) in Type Ii Achalasia Associated with Increased Intraesophageal Pressure During Swallowing

Tu1246 – High Residual Upper Esophageal Sphincter Pressure (UESP) in Type Ii Achalasia Associated with Increased Intraesophageal Pressure During Swallowing

Results of portosystemic shunting in patients with hepatic cirrhosis and ascites syndrome

Purpose. Assess the results of portal systemic shunting (PSSh) in patients with liver cirrhosis (LC) with ascitic syndrome.&#x0D; Materials and methods. Analyse the results of PSSh in 556 patients operated a year from 2000 to 2015. The basis of the analysis taken all the features related to the development and progression of ascitic syndrome. Depending on the shunt type, research conducted with most frequently performed shunts groups.&#x0D; Results. Initial decompensated cirrhosis by edema-ascites syndrome significantly increases the risk of specific complications such as hepatic insufficiency from 6.9% to 13.5%, hepatic encephalopathy from 12.1% to 16.2% and increase in ascites from 7.2% to 16.2%, and the mortality rate from 2.1% to 3.8%. The main cause of early mortality after PSSh is a risk of thrombosis of the anastomosis with recurrent bleeding, whereas other specific complications, conservative measures allow neutralizing the difference in the index of satisfactory results of the operation (96.2% — in the group with ascites before PSSh against; 97.9% — in the group without ascites). Quantitative and qualitative analysis of ascites showed that in the coming period after the shunt (3-5 days) the development of this complication depends on the type of bypass surgery, so when the distal splenorenal shunts (DSRS) production of ascites significantly increased (P &lt;0,01), while total protein component fluid significantly (P &lt;0,02) higher than in patients in ascites with central bypass type. This fact is due to the formation of the selective type of bypass on the background of DSRS, and the growth of ascites does not depend on the presence of complications before surgery, indicating that the impact factor of the severity of portal hypertension and therefore the adequacy of decompression of the portal vein system, against which a decrease in blood albumin fraction and increase it in ascites (R2 = 0,57) may be indicative of a high residual portal pressure.&#x0D; Conclusion. In patients with cirrhosis after PSSh in 70.2% of cases of decompensation of ascites syndrome is caused directly with cirrhotic process and the growth of functional impairment of hepatocytes, the remaining 29.8% of cases, the formation of the complications associated with the progression of PH syndrome on the background of anastomotic thrombosis.

Performance of the Labcor Dokimos Plus pericardial aortic prosthesis: a single-centre experience.

In patients with a small aortic annulus, aortic valve replacement (AVR) is frequently associated with high residual pressure gradients. Supra-annular pericardial aortic prostheses are gaining popularity due to the increased effective orifice areas (EOA) and resulting lower gradients. This study reports the clinical and echocardiographic results following implantation of the new supra-annular pericardial aortic prosthesis Dokimos Plus (Labcor, Belo Horizonte, Brazil). Between October 2013 and July 2015, 137 patients (41% women, mean age: 74 years) underwent supra-annular AVR with or without concomitant procedures using the Dokimos Plus prosthesis in our department. Transthoracic echocardiography was performed pre- and postoperatively on all patients to assess haemodynamic parameters (gradients, acceleration time [AT], Doppler velocity indices [DVIs] and indexed EOA [EOAI]) and to detect paravalvular leakage (PVL). Data were collected retrospectively from our hospital databases. Patients were grouped by prosthesis size: Most patients received 23-mm (57.6%), followed by 21-mm (19%), 25-mm (15.4%) and 27-mm (8%) prostheses. The mean EOAI in all groups was 1.1 ± 0.26 cm 2 /m 2 . Pressure gradients were low in all groups (mean: 8.9 ± 4.4 mmHg; peak: 18.8 ± 6.8 mmHg); AT and DVI were in the normal range according to American Society of Echocardiography/European Association of Cardiovascular Imaging recommendations (mean AT 73.3 ± 29 ms; mean DVI 0.5 ± 0.2). One patient had severe PVL and one presented with central regurgitation, both requiring re-intervention. The mortality rate was 5.1% ( n = 7); none of the cases was associated with valve insufficiency. The Dokimos prosthesis showed a satisfactory overall performance, presenting low gradients and DVIs as well as high EOAI. Further investigations are needed to analyse the cases of regurgitation and monitor long-term performance.

Distribution of structural impurities and fluid microinclusions in cubic and coated diamond crystals from the Udachnaya pipe, Yakutia, Russia

FTIR microspectroscopic data were used to construct two-dimension maps showing the distribution of structural impurities and mineral microinclusions in cubic and coated octahedral diamond crystals from the Udachnaya kimberlite pipe in Yakutia. Elevated concentrations of hydrogen and total nitrogen are detected in parts corresponding to the early growth of single-episode growth regions of diamond crystals. These concentrations decrease toward the peripheral portions of these regions. The microinclusions contain water and polyphase mineral associations that preserve a high residual pressure. Microinclusions in the coats of octahedral diamond crystals are dominated by silicates, in which the intensity of IR spectral bands increases toward the peripheries, whereas the cubes posses irregularly distributed domains rich in these phases. The carbonate phases of the microinclusions are distributed according to growth zones of the crystals, and their distribution is often not correlated with the concentrations of structural impurities. The facts that microinclusions in the diamond cuboids are dominated by carbonates and that the rims of the octahedra are dominated by silicates suggest that the diamonds crystallized from dominantly carbonate and silicate fluids/ melts, respectively. The chemical composition of the microinclusions point to an eclogitic paragenesis of the crystals. Facts are obtained that provide support for the earlier hypothesis that cubic diamond crystals and coated octahedral crystals grow at metasomatic interaction between deep fluids and eclogitic rocks in the lithospheric mantle.

The biomechanical characteristics of the pharynx in patients with aspiration after radiotherapy for nasopharyngeal carcinoma

Objective To explore the biomechanical characteristics of the pharynx in patients with aspiration after radiotherapy for nasopharyngeal carcinoma (NPC). Methods Clinical data on NPC patients with dysphagia admitted between July 2011 and June 2015 were retrospectively analyzed. Twenty-three patients were found who had received videofluoroscopic swallowing studies (VFSSs) and whose pharyngeal pressure and upper esophageal sphincter (UES) relaxing were tested using high-resolution solid-state manometry (HRM). The cases were divided into an aspiration group and a non-aspiration group according to the VFSS results. Differences in biomechanical parameters between the 2 groups when taking food of different viscosity were compared. Results Patients with aspiration had significantly higher UES residual pressure when taking thick liquids (20.1±14.3 mmHg) and paste (18.0±14.3 mmHg) than patients not aspirating (9.3±9.2 mmHg and 7.2±8.9 mmHg for thick liquid and paste respectively). But no significant difference in average pharyngeal pressure between the two groups was observed. Conclusion Aspiration after radiotherapy may be correlated with increased UES residual pressure. Key words: Dysphagia; Aspiration; Nasopharyngeal carcinoma; Radiotherapy

Eocene to Oligocene retrogression and recrystallization of the Stak eclogite in northwest Himalaya

Highly retrogressed eclogite is present in the Stak massif located on the northern edge of the Indian continental margin in northern Pakistan. Garnet in foliated samples contains omphacite inclusions (Xjd=0.33–0.40) and quartz inclusions and latter retain Raman spectroscopic evidence for high residual pressures up to 0.52GPa. These garnet grains do not show apparent compositional zoning. By contrast, one sample contains euhedral grains of garnet with quartz inclusions that show residual pressures as low as 0.25GPa. These garnet grains do not contain omphacite inclusions, and show different compositional zoning compared to the omphacite-bearing garnet. The metamorphic condition of this sample was estimated to be 1.0–1.4GPa/650–710°C using residual pressure values of quartz inclusions in garnets and the garnet–clinopyroxene geothermometer. The U–Pb ages of zircon grains range from 158 to 28Ma with a cluster between at ca. 32Ma, which is younger than that of the peak ultrahigh-pressure metamorphic ages of eclogitic massifs in the northwestern Himalaya, e.g. Kaghan and Tso Morari. We suggest that the retrogressed eclogitic rocks in the Stak massif were heated by nearby Nanga Parbat Haramosh massif at ca. 32Ma, subsequent to peak eclogite facies conditions. During this heating, part of the eclogite was largely recrystallized to form euhedral garnet grains. These results suggest that the Stak massif resided at a lower crustal depth while other ultrahigh-pressure massifs were exhumed in western Himalaya.

OC-071 Oesophageal physiology findings in 80 patients with recurrent dysphagia post-achalasia treatment: retest before retreating

Introduction Achalasia is a relatively rare primary oesophageal motor disorder characterised by absent peristalsis and failure of relaxation of the lower oesophageal sphincter (LOS). The standards of treatment for achalasia are pneumatic balloon dilatation and surgical myotomy. Although 85–95% success at 2 years is reported with these procedures, in the longer term, dysphagia may return in over 50%, prompting consideration of re-treatment. The definition of recurrence is often based on symptom evaluation, particularly dysphagia. Treatment of dysphagia in achalasia is targeted at the LOS, but in some patients dysphagia may be multifactorial and may not be improved by attempting to further lower LOS pressure. We aimed to evaluate the GI physiological findings of patients undergoing studies in our tertiary referral unit to investigate recurrence of dysphagia post-treatment. Method We interrogated our database for patients undergoing high resolution oesophageal manometry +/- 24-hour pH studies due to dysphagia post-treatment for achalasia between 2010–2014. We recorded achalasia subtype, LOS relaxation pressure (known as integrated relaxation pressure, or IRP), and reflux study results if performed. Results 80 eligible patients (38 female; age range 11–83 years, median 46 years) were identified with recurrent dysphagia. All had high resolution oesophageal manometry performed, and 18 patients had 24-hour pH studies due to concomitant heartburn and/or regurgitation. 52 patients had undergone at least one previous pneumatic dilatation, 23 had undergone surgical myotomy, and 5 had no response to Botox injection. 40 patients were found to have type 1 achalasia, 25 had type 2 achalasia, and 6 had type 3 achalasia. 9 patients had normal peristalsis unlikely to be consistent with a diagnosis of achalasia. 22 of the 80 patients had an IRP >15 mmHg (upper range of normal). 10 patients had a very low ( Conclusion We investigated a large cohort of patients with recurrent dysphagia post-treatment of achalasia. The most frequent achalasia subtype was type 1. Although 28% patients had high residual LOS pressures, a significant proportion of patients had findings not consistent with a need to re-treat with dilatation or myotomy (due to very low LOS pressure, gastro-oesophageal reflux disease, or possible incorrect diagnosis). These results highlight the need to carefully re-evaluate patients presenting with recurrent dysphagia after achalasia treatment before deciding on repeat therapy. Disclosure of interest None Declared.

Composite metamorphic history recorded in garnet porphyroblasts of Sambagawa metasediments in the Besshi region, central Shikoku, Southwest Japan

AbstractThis report describes an investigation of the composite metamorphic history recorded in garnet porphyroblasts of Sambagawa metasediments, and presents discussions of the possible distribution of eclogite facies lithologies in the Besshi region, central Shikoku, southwest Japan. Garnet grains usually show chemically composite zoning with resolved inner and overgrown outer segments, respectively. The inner segment usually contains paragonite as a sodic phase inclusion and rarely contains omphacite or glaucophane, whereas the outer segment rarely includes albite but no paragonite. The inner segment often includes quartz grains that preserve high residual pressures corresponding to the eclogite facies conditions, whereas the outer segment includes quartz grains that preserve lower residual pressures corresponding to the epidote–amphibolite facies conditions. For this composite‐zoned garnet, the assemblage of sodic phase inclusions and the values of the residual pressure of quartz inclusions imply the following successive metamorphic path: prograde eclogite facies stage → decompression and hydration reaction stage → prograde epidote–amphibolite facies stage. Metasediments containing this composite‐zoned garnet with such evidence for eclogite facies conditions are more widely distributed than the eclogitic lithologies that contain the assemblage of omphacite + garnet. These results imply that the combination of (i) the chemical composite zoning of garnet, (ii) the nature of sodic phase inclusions, and (iii) the residual pressure of quartz inclusions is useful as criteria to ascertain the true distribution of the lithologies that have experienced eclogite facies metamorphism for the Sambagawa metasediments, which was difficult to recognize in earlier studies.

Petrogenesis and implications of jadeite‐bearing kyanite eclogite from the Sanbagawa belt (SW Japan)

AbstractJadeite‐bearing kyanite eclogite has been discovered in the Iratsu body of the Sanbagawa belt, SW Japan. The jadeite + kyanite assemblage is stable at higher pressure–temperature (P–T) conditions or lower H2O activity [a(H2O)] than paragonite, although paragonite‐bearing eclogite is common in the Sanbagawa belt. The newly discovered eclogite is a massive metagabbro with the peak‐P assemblage garnet + omphacite + jadeite + kyanite + phengite + quartz + rutile. Impure jadeite is exclusively present as inclusions in garnet. The compositional gap between the coexisting omphacite (P2/n) and impure jadeite (C2/c) suggests relatively low metamorphic temperatures of 510–620 °C. Multi‐equilibrium thermobarometry for the assemblage garnet + omphacite + kyanite + phengite + quartz gives peak‐P conditions of ~2.5 GPa, 570 °C. Crystallization of jadeite in the metagabbro is attributed to Na‐ and Al‐rich effective bulk composition due to the persistence of relict Ca‐rich clinopyroxene at the peak‐P stage. By subtracting relict clinopyroxene from the whole‐rock composition, pseudosection modelling satisfactorily reproduces the observed jadeite‐bearing assemblage and mineral compositions at ~2.4–2.5 GPa, 570–610 °C and a(H2O) &gt;0.6. The relatively high pressure conditions derived from the jadeite‐bearing kyanite eclogite are further supported by high residual pressures of quartz inclusions in garnet. The maximum depth of exhumation in the Sanbagawa belt (~80 km) suggests decoupling of the slab–mantle wedge interface at this depth.

Application of a high-cycle accumulation model to the analysis of soil liquefaction around a vibrating pile toe

High residual pore pressure observed in the vicinity of piles driven in saturated soil indicates that the soil around the pile may be liquefied. In the present paper, the problem of deformation of saturated sand around a vibrating pile is formulated with the use of a high-cycle accumulation model capable of describing a large number of cycles. The problem is solved numerically for locally undrained conditions in spherically symmetric formulation suitable for the lower part of a cylindrical closed-ended pile near the toe. The aim of the study is to calculate the evolution of the liquefaction zone around the pile for a large number of cycles. A parametric study is carried out to show how the growth of the liquefaction zone depends on the pile displacement amplitude, the relative soil density, the effective stress in the far field and the pore fluid compressibility.

Dysphagia and Gastroesophageal Junction Resistance to Flow Following Partial and Total Fundoplication

BackgroundEsophageal peristalsis and basal gastroesophageal junction (GEJ) pressure correlate poorly with dysphagia. AimTo determine intraluminal pressures that reflect GEJ function and to determine manometric correlates for dysphagia before and after fundoplication. MethodsThe relationships between maximal intrabolus pressure, residual GEJ relaxation pressure and peak peristaltic pressure for water swallows were determined in normal volunteers and patients with reflux disease before and after fundoplication. GEJ anatomy was assessed by radiological, endoscopic and surgical criteria, whilst dysphagia was measured with a validated composite dysphagia score. ResultsDysphagia was significantly associated with lower peak peristaltic pressure in the distal esophagus and the presence of a hiatus hernia preoperatively, as well as higher residual pressure on GEJ relaxation postoperatively. Peak distal peristaltic pressure and residual GEJ relaxation pressure were predictors of intrabolus pressure after total fundoplication (p < 0.002). Residual GEJ relaxation pressure was four times higher after 360° fundoplication (N = 19) compared to 90° fundoplication (N = 14, p < 0.0001). Similarly, intrabolus pressure was elevated 2.5 times after 360° fundoplication and nearly doubled after 90° fundoplication and both were significantly different from controls (N = 22) and reflux disease patients (N = 53, p < 0.0001). ConclusionsGastroesophageal junction impedance to flow imposed by fundoplication is associated with dysphagia when there is suboptimal distal esophageal contraction strength and relatively high residual GEJ relaxation pressure.