Reconsideration of the Gastroparetic Syndrome.

PURPOSE OF REVIEW: Gastroparesis is a chronic disorder characterized by a constellation of foregut symptoms, including postprandial nausea, vomiting, distension, epigastric pain, and regurgitation in the absence of gastric outlet obstruction. Despite considerable research over the past decades, there remains to be only nominal understanding of disease classification, diagnostic criteria, pathogenesis, and preferred therapy. RECENT FINDINGS: We critically reassess current approaches for disease identification and stratification, theories of causation, and treatment for gastroparesis. Gastric scintigraphy, long considered a diagnostic standard, has been re-evaluated in light of evidence showing low sensitivity, whereas newer testing modalities are incompletely validated. Present concepts of pathogenesis do not provide a unified model linking biological impairments with clinical manifestations, whereas available pharmacological and anatomical treatments lack explicit selection criteria or evidence for sustained effectiveness. We propose a disease model that embodies the re-programming of distributed neuro-immune interactions in the gastric wall by inflammatory perturbants. These interactions, combined with effects on the foregut hormonal milieu and brain-gut axis, are postulated to generate the syndromic attributes characteristically linked with gastroparesis. Research linking models of immunopathogenesis with diagnostic and therapeutic paradigms will lead to reclassifications of gastroparesis that guide future trials and technological developments. KEY POINTS: • The term gastroparesis embodies a heterogenous array of symptoms and clinical findings based on a complex assimilation of afferent and efferent mechanisms, gastrointestinal locations, and pathologies. • There currently exists no single test or group of tests with sufficient capacity to be termed a definitional standard for gastroparesis. • Present research regarding pathogenesis suggests the importance of immune regulation of intrinsic oscillatory activity involving myenteric nerves, interstitial cells of Cajal, and smooth muscle cells. • Prokinetic pharmaceuticals remain the mainstay of management, although novel treatments are being studied that are directed to alternative muscle/nerve receptors, electromodulation of the brain-gut axis, and anatomical (endoscopic, surgical) interventions.

Does Caudate Resection Improve Outcomes of Patients Undergoing Curative Resection for Perihilar Cholangiocarcinoma? A Systematic Review and Meta-Analysis.

BACKGROUND: Margin-negative (R0) resection is the strongest positive prognostic factor in perihilar cholangiocarcinoma (PHC). Due to its anatomic location, the caudate lobe is frequently involved in PHC. This review aimed to examine the impact of caudate lobe resection (CLR) in addition to hepatectomy and bile duct resection for patients with PHC. METHODS: The MEDLINE, EMBASE, and Cochrane databases were systematically reviewed from inception to October 2021 to identify studies comparing patients undergoing surgical resection with hepatectomy and bile duct resection with or without CLR for treatment of PHC. Outcomes included the proportion of patients achieving R0 resection, overall survival (OS), and perioperative morbidity. RESULTS: Altogether, 949 studies were screened. The review included eight observational studies reporting on 1137 patients. The patients who underwent CLR had a higher likelihood of R0 resection (odds ratio [OR], 5.85; 95% confidence interval [CI], 2.64-12.95) and a better OS (hazard ratio [HR], 0.65; 95% CI, 0.54-0.79) than those who did not. The use of CLR did not increase the risk of perioperative morbidity (OR, 1.03; 95% CI, 0.65-1.63). CONCLUSIONS: Given the higher likelihood of R0 resection, improved OS, and no apparent increase in perioperative morbidity, this review supports routine caudate lobectomy in the surgical management of PHC. These results should be interpreted with caution given the lack of high-quality prospective data and the high probability of selection bias.

Does Intraoperative Frozen Section and Revision of Margins Lead to Improved Survival in Patients Undergoing Resection of Perihilar Cholangiocarcinoma? A Systematic Review and Meta-analysis.

BACKGROUND: Perihilar cholangiocarcinoma (PHC) is a rare malignancy that arises at the biliary confluence. Achieving a margin-negative resection (R0) is challenging given the anatomic location of tumors and remains the most important prognostic indicator of long-term survival. The objective of this study is to review the impact of intraoperative revision of positive biliary margins in PHC on oncologic outcomes. PATIENTS AND METHODS: Electronic databases were searched from inception to October 2021. Studies comparing three types of patients undergoing resection of PHC with intraoperative frozen section of the proximal and/or distal bile ducts were identified: those who were margin-negative (R0), those with an initially positive margin who had revised negative margins (R1R0), and those with a persistently positive margin with or without revision of a positive margin (R1). The primary outcome was overall survival (OS). Secondary outcomes included risk of postoperative complication. RESULTS: A total of 449 studies were screened. Ten retrospective observational studies reporting on 1955 patients were included. Patients undergoing successful revision of a positive proximal and/or distal bile duct margin (R1R0) had similar OS to those with a primary margin-negative resection (R0) [hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.72-1.19, p = 0.56, I2 = 84%], and significantly better OS than patients with a positive final bile duct margin (R1) (HR 0.52, 95% CI 0.34-0.79, p = 0.002, I2 = 0%). There was no increase in the risk of postoperative complications associated with additional resection, although postoperative morbidity was inconsistently reported. CONCLUSIONS: This review supports routine intraoperative biliary margin evaluation during resection of PHC with revision if technically feasible.

Outcomes of Patients Undergoing Elective Bowel Resection Before and After Implementation of an Anemia Screening and Treatment Program.

BACKGROUND: Patients with anemia undergoing elective colorectal cancer surgery are known to have significantly higher rates of postoperative complications and worse outcomes. OBJECTIVE: This study aimed to improve rates of anemia screening and treatment in patients undergoing elective colon and rectal resections through a quality improvement initiative. DESIGN: We compared a historical cohort of patients before implementation of our anemia screening and treatment quality improvement program to a prospective cohort after implementation. SETTINGS: This study was conducted at a tertiary care hospital. PATIENTS: This study included all adult patients with a new diagnosis of colon or rectal cancer without evidence of metastatic disease between 2017 and 2019. INTERVENTIONS: The interventions include the anemia screening and treatment quality improvement program. MAIN OUTCOME MEASURES: The primary outcome was hospital cost per admission. RESULTS: This study includes a total of 84 patients who underwent elective colon or rectal resection before implementation of our anemia quality improvement project and 88 patients who underwent surgery after. In the preimplementation cohort 44 of 84 patients (55.9%) were anemic compared to 47 of 99 patients (54.7%) in the postimplementation cohort. Rates of screening (25%-86.4%) and treatment (27.8%- 63.8%) were significantly increased in the postimplementation cohort. Mean total cost per admission was significantly decreased in the postimplementation cohort (mean cost $16,827 vs $25,796; p = 0.004); this significant reduction was observed even after adjusting for relevant confounding factors (ratio of means: 0.74; 95% CI, 0.65-0.85). The mechanistic link between treatment of anemia and reductions in cost remains unknown. No significant difference was found in rates of blood transfusion, complications, or mortality between the groups. LIMITATIONS: The study limitation includes before-after design subjected to selection and temporal biases. CONCLUSIONS: We demonstrate the successful implementation of an anemia screening and treatment program. This program was associated with significantly reduced cost per admission. This work demonstrates possible value and benefits of implementation of an anemia screening and treatment program. See Video Abstract at http://links.lww.com/DCR/C15 .RESULTADOS DE LOS PACIENTES SOMETIDOS A RESECCIÓN INTESTINAL ELECTIVA ANTES Y DESPUÉS DE LA IMPLEMENTACIÓN DE UN PROGRAMA DE DETECCIÓN Y TRATAMIENTO DE ANEMIA. ANTECEDENTES: Se sabe que los pacientes anémicos que se someten a una cirugía electiva de cáncer colorrectal tienen tasas significativamente más altas de complicaciones posoperatorias y peores resultados. OBJETIVO: Mejorar las tasas de detección y tratamiento de la anemia en pacientes sometidos a resecciones electivas de colon y recto a través de una iniciativa de mejora de calidad. DISEO: Comparamos una cohorte histórica de pacientes antes de la implementación de nuestro programa de detección de anemia y mejora de la calidad del tratamiento con una cohorte prospectiva después de la implementación. ENTORNO CLINICO: Hospital de atención terciaria. PACIENTES: Todos los pacientes adultos con un nuevo diagnóstico de cáncer de colon o recto sin evidencia de enfermedad metastásica entre 2017 y 2019. INTERVENCIONES: Detección de anemia y programa de mejora de la calidad del tratamiento. PRINCIPALES MEDIDAS DE RESULTADO: El resultado primario fue el costo hospitalario por ingreso. RESULTADOS: Un total de 84 pacientes se sometieron a resección electiva de colon o recto antes de la implementación de nuestro proyecto de mejora de calidad de la anemia y 88 pacientes se sometieron a cirugía después. En la cohorte previa a la implementación, 44/84 (55,9 %) presentaban anemia en comparación con 47/99 (54,7 %) en la cohorte posterior a la implementación. Las tasas de detección (25 % a 86,4 %) y tratamiento (27,8 % a 63,8 %) aumentaron significativamente en la cohorte posterior a la implementación. El costo total medio por admisión se redujo significativamente en la cohorte posterior a la implementación (costo medio $16 827 vs. $25 796, p = 0,004); esta reducción significativa se observó incluso después de ajustar los factores de confusión relevantes (proporción de medias: 0,74, IC del 95 %: 0,65 a 0,85). El vínculo mecánico entre el tratamiento de la anemia y la reducción de costos sigue siendo desconocido. No hubo diferencias significativas en las tasas de transfusión de sangre, complicaciones o mortalidad entre los grupos. LIMITACIONES: El diseño de antes y después está sujeto a sesgos temporales y de selección. CONCLUSIONES: Demostramos la implementación exitosa de un programa de detección y tratamiento de anemia. Este programa se asoció con un costo por admisión significativamente reducido. Este trabajo demuestra el valor y los beneficios posibles de la implementación de un programa de detección y tratamiento de la anemia. Consulte Video Resumen en http://links.lww.com/DCR/C15 . (Traducción- Dr. Francisco M. Abarca-Rendon ).

Lipid and smooth muscle architectural pathology in the rabbit atherosclerotic vessel wall using Q-space cardiovascular magnetic resonance.

BACKGROUND: Atherosclerosis is an arterial vessel wall disease characterized by slow, progressive lipid accumulation, smooth muscle disorganization, and inflammatory infiltration. Atherosclerosis often remains subclinical until extensive inflammatory injury promotes vulnerability of the atherosclerotic plaque to rupture with luminal thrombosis, which can cause the acute event of myocardial infarction or stroke. Current bioimaging techniques are unable to capture the pathognomonic distribution of cellular elements of the plaque and thus cannot accurately define its structural disorganization. METHODS: We applied cardiovascular magnetic resonance spectroscopy (CMRS) and diffusion weighted CMR (DWI) with generalized Q-space imaging (GQI) analysis to architecturally define features of atheroma and correlated these to the microscopic distribution of vascular smooth muscle cells (SMC), immune cells, extracellular matrix (ECM) fibers, thrombus, and cholesteryl esters (CE). We compared rabbits with normal chow diet and cholesterol-fed rabbits with endothelial balloon injury, which accelerates atherosclerosis and produces advanced rupture-prone plaques, in a well-validated rabbit model of human atherosclerosis. RESULTS: Our methods revealed new structural properties of advanced atherosclerosis incorporating SMC and lipid distributions. GQI with tractography portrayed the locations of these components across the atherosclerotic vessel wall and differentiated multi-level organization of normal, pro-inflammatory cellular phenotypes, or thrombus. Moreover, the locations of CE were differentiated from cellular constituents by their higher restrictive diffusion properties, which permitted chemical confirmation of CE by high field voxel-guided CMRS. CONCLUSIONS: GQI with tractography is a new method for atherosclerosis imaging that defines a pathological architectural signature for the atheromatous plaque composed of distributed SMC, ECM, inflammatory cells, and thrombus and lipid. This provides a detailed transmural map of normal and inflamed vessel walls in the setting of atherosclerosis that has not been previously achieved using traditional CMR techniques. Although this is an ex-vivo study, detection of micro and mesoscale level vascular destabilization as enabled by GQI with tractography could increase the accuracy of diagnosis and assessment of treatment outcomes in individuals with atherosclerosis.

The SGLT2i Dapagliflozin Reduces RV Mass Independent of Changes in RV Pressure Induced by Pulmonary Artery Banding.

BACKGROUND: Sodium glucose linked transporter 2 (SGLT2) inhibition not only reduces morbidity and mortality in patients with diagnosed heart failure but also prevents the development of heart failure hospitalization in those at risk. While studies to date have focused on the role of SGLT2 inhibition in left ventricular failure, whether this drug class is efficacious in the treatment and prevention of right heart failure has not been explored. HYPOTHESIS: We hypothesized that SGLT2 inhibition would reduce the structural, functional, and molecular responses to pressure overload of the right ventricle. METHODS: Thirteen-week-old Fischer F344 rats underwent pulmonary artery banding (PAB) or sham surgery prior to being randomized to receive either the SGLT2 inhibitor: dapagliflozin (0.5 mg/kg/day) or vehicle by oral gavage. After 6 weeks of treatment, animals underwent transthoracic echocardiography and invasive hemodynamic studies. Animals were then terminated, and their hearts harvested for structural and molecular analyses. RESULTS: PAB induced features consistent with a compensatory response to increased right ventricular (RV) afterload with elevated mass, end systolic pressure, collagen content, and alteration in calcium handling protein expression (all p < 0.05 when compared to sham + vehicle). Dapagliflozin reduced RV mass, including both wet and dry weight as well as normalizing the protein expression of SERCA 2A, phospho-AMPK and LC3I/II ratio expression (all p < 0.05). SIGNIFICANCE: Dapagliflozin reduces the structural, functional, and molecular manifestations of right ventricular pressure overload. Whether amelioration of these early changes in the RV may ultimately lead to a reduction in RV failure remains to be determined.

Implementation, results and face validity of the Consultation and Relational Empathy measure in a Canadian department of surgery.

BACKGROUND: The Consultation and Relational Empathy (CARE) Measure, a validated questionnaire designed to assess patients' perceptions of their physician's communication skills and empathy, has been used to assess empathy in medical specialties but has seldom been applied to surgery. We assessed empathy and communication skills among a group of surgeons within a single academic institution. METHODS: All surgeons within our department of surgery were invited to participate. Patients seen in clinics of participating surgeons were recruited prospectively from July 2018 to February 2019. At the end of each clinical encounter, they were asked to complete a CARE survey. Surveys were analyzed according to previously validated inclusion and exclusion criteria. We calculated mean scores for each surgeon and surgical division. About 6 months after study completion, surgeons were provided with their individual score and de-identified division scores, and were asked to complete a follow-up survey assessing their attitudes toward the CARE Measure. RESULTS: Of the 82 surgeons invited, 51 (62%) agreed to participate; 7 had fewer than 25 completed surveys and were excluded from analysis. A total of 1801 surveys for 44 surgeons (33 male and 11 female) were included in the final analysis. The average CARE score across the department was 46.9 (95% confidence interval [CI] 46.6-47.1). Female surgeons received significantly higher scores than male surgeons (mean 47.6 [95% CI 47.1-48.0] v. 46.7 [95% CI 46.4-48.0]). Of the 35 surgeons who responded to the follow-up survey, 31 (89%) felt that the questions in the CARE Measure applied to their practice, and half of these reported that they intended to make changes in response to the feedback. CONCLUSION: We found high communication and empathy scores among surgeons in the outpatient setting, with enough variability to encourage continued improvement. The CARE Measure appears to have face validity among surgeons, and the vast majority found it relevant to their practice. Further study is needed to formally assess the relevance, performance, reliability and construct validity of this measure.

The impact of prophylactic negative pressure wound therapy on surgical site infections in pancreatic resection: A systematic review and meta-analysis.

BACKGROUND: Surgical site infections (SSI) cause significant morbidity. Prophylactic negative pressure wound therapy (NPWT) may promote wound healing and decrease SSI. The objective is to evaluate the effect of prophylactic NPWT on SSI in patients undergoing pancreatectomy. METHODS: Electronic databases were searched from inception until April 2022. Randomized controlled trials (RCTs) comparing prophylactic NPWT to standard dressings in patients undergoing pancreatectomy were included. The primary outcome was the risk of SSI. Secondary outcomes included the risk of superficial and deep SSI and organ space infection (OSI). Random effects models were used for meta-analysis. RESULTS: Four single-centre RCTs including 309 patients were identified. Three studies were industry-sponsored, and two were at high risk of bias. There was no significant difference in the risk of SSI in patients receiving NPWT vs. control (14% vs. 21%, RR = 0.72, 95%CI = 0.32-1.60, p = 0.42, I2 = 53%). Likewise, there was no significant difference in the risk of superficial and deep SSI or OSI. No significant difference was found on subgroup analysis of patients at high risk of wound infection or on sensitivity analysis of studies at low risk of bias. CONCLUSION: Prophylactic NPWT does not significantly decrease the risk of SSI among patients undergoing pancreatectomy. Insufficient evidence exists to justify the routine use of NPWT.

Amino terminus of cardiac myosin binding protein-C regulates cardiac contractility.

Phosphorylation of cardiac myosin binding protein-C (cMyBP-C) regulates cardiac contraction through modulation of actomyosin interactions mediated by the protein's amino terminal (N')-region (C0-C2 domains, 358 amino acids). On the other hand, dephosphorylation of cMyBP-C during myocardial injury results in cleavage of the 271 amino acid C0-C1f region and subsequent contractile dysfunction. Yet, our current understanding of amino terminus region of cMyBP-C in the context of regulating thin and thick filament interactions is limited. A novel cardiac-specific transgenic mouse model expressing cMyBP-C, but lacking its C0-C1f region (cMyBP-C∆C0-C1f), displayed dilated cardiomyopathy, underscoring the importance of the N'-region in cMyBP-C. Further exploring the molecular basis for this cardiomyopathy, in vitro studies revealed increased interfilament lattice spacing and rate of tension redevelopment, as well as faster actin-filament sliding velocity within the C-zone of the transgenic sarcomere. Moreover, phosphorylation of the unablated phosphoregulatory sites was increased, likely contributing to normal sarcomere morphology and myoarchitecture. These results led us to hypothesize that restoration of the N'-region of cMyBP-C would return actomyosin interaction to its steady state. Accordingly, we administered recombinant C0-C2 (rC0-C2) to permeabilized cardiomyocytes from transgenic, cMyBP-C null, and human heart failure biopsies, and we found that normal regulation of actomyosin interaction and contractility was restored. Overall, these data provide a unique picture of selective perturbations of the cardiac sarcomere that either lead to injury or adaptation to injury in the myocardium.

Intraoperative Red Blood Cell Transfusion Decision-making: A Systematic Review of Guidelines.

OBJECTIVES: The objective of this work was to carry out a systematic review of clinical practice guidelines (CPGs) pertaining to intraoperative red blood cell (RBC) transfusions, in terms of indications, decision-making, and supporting evidence base. SUMMARY OF BACKGROUND DATA: RBC transfusions are common during surgery and there is evidence of wide variability in practice. METHODS: Major electronic databases (MEDLINE, EMBASE, and CINAHL), guideline clearinghouses and Google Scholar were systematically searched from inception to January 2019 for CPGs pertaining to indications for intraoperative RBC transfusion. Eligible guidelines were retrieved and their quality assessed using AGREE II. Relevant recommendations were abstracted and synthesized to allow for a comparison between guidelines. RESULTS: Ten guidelines published between 1992 and 2018 provided indications for intraoperative transfusions. No guideline addressed intraoperative transfusion decision-making as its primary focus. Six guidelines provided criteria for transfusion based on hemoglobin (range 6.0-10.0 g/dL) or hematocrit (<30%) triggers. In the absence of objective transfusion rules, CPGs recommended considering other parameters such as blood loss (n = 7), signs of end organ ischemia (n = 5), and hemodynamics (n = 4). Evidence supporting intraoperative recommendations was extrapolated primarily from the nonoperative setting. There was wide variability in the quality of included guidelines based on AGREE II scores. CONCLUSION: This review has identified several clinical practice guidelines providing recommendations for intraoperative transfusion. The existing guidelines were noted to be highly variable in their recommendations and to lack a sufficient evidence base from the intraoperative setting. This represents a major knowledge gap in the literature.

Impact of empagliflozin on right ventricular parameters and function among patients with type 2 diabetes.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibition reduces cardiovascular events in type 2 diabetes (T2DM) and is associated with a reduction in left ventricular (LV) mass index. However, the impact on right ventricular (RV) remodeling is unknown. Accordingly, the objective of this study was to assess the impact of SGLT2 inhibition on RV parameters and function in T2DM and coronary artery disease (CAD). METHODS: In EMPA-HEART CardioLink-6, 97 patients with T2DM and CAD were randomly assigned to empagliflozin 10 mg (n = 49) once daily or placebo (n = 48). Cardiac magnetic resonance imaging was performed at baseline and after 6 months. RV mass index (RVMi), RV end-diastolic and end-systolic volume index (RVEDVi, RVESVi) and RV ejection fraction (RVEF) were assessed in blinded fashion. RESULTS: At baseline, mean RVMi (± SD) (11.8 ± 2.4 g/m2), RVEF (53.5 ± 4.8%), RVEDVi (64.3 ± 13.2 mL/m2) and RVESVi (29.9 ± 6.9 mL/m2) were within normal limits and were similar between the empagliflozin and placebo groups. Over 6 months, there were no significant differences in RVMi (- 0.11 g/m2, [95% CI - 0.81 to 0.60], p = 0.76), RVEF (0.54%, [95% CI - 1.4 to 2.4], p = 0.58), RVEDVi (- 1.2 mL/m2, [95% CI - 4.1 to 1.7], p = 0.41) and RVESVi (- 0.81 mL/m2, [95% CI - 2.5 to 0.90], p = 0.35) in the empaglifozin group as compared with the placebo group. In both groups, there was no significant correlation between RVMi and LVMi changes from baseline to 6 months. CONCLUSIONS: In this post-hoc analysis, SGLT2 inhibition with empagliflozin had no impact on RVMi and RV volumes in patients with T2DM and CAD. The potentially differential effect of empagliflozin on the LV and RV warrants further investigation. CLINICAL TRIAL REGISTRATION: URL:  https://www.clinicaltrials.gov/ct2/show/NCT02998970?cond=NCT02998970&draw=2&rank=1 . Unique identifier: NCT02998970.

Late intervention in the remnant kidney model attenuates proteinuria but not glomerular filtration rate decline.

AIM: The use of animal models to predict the response to new therapies in humans is a vexing issue in nephrology. Unlike patients with chronic kidney disease (CKD), few rodent models develop a progressive decline in glomerular filtration rate (GFR) so that experimental studies frequently report a reduction in proteinuria as the primary efficacy outcome. Moreover, while humans present with established kidney disease that continues to progress, many experimental studies investigate therapies in the prevention rather than in a therapeutic setting. METHODS: We used the remnant kidney (subtotal nephrectomy [SNX]) rat model that develops a decline in GFR in conjunction with heavy proteinuria and hypertension along with the histological hallmarks of CKD in humans, glomerulosclerosis and tubulointerstitial fibrosis. Using agents that had been shown to improve GFR as well as proteinuria in the prevention setting, angiotensin-converting enzyme (ACE) inhibition with enalapril and SIRT1 activation with SRT3025, treatment was initiated 6 weeks after SNX. RESULTS: While enalapril reduced blood pressure, proteinuria and histological injury, it did not improve GFR, as measured by inulin clearance. SRT3025 improved neither GFR nor structural damage despite a reduction in proteinuria. CONCLUSION: These findings demonstrate that neither a reduction in proteinuria nor a reversal of structural damage in the kidney will necessarily translate to a restoration of kidney function.

Renal microvascular oxygen tension during hyperoxia and acute hemodilution assessed by phosphorescence quenching and excitation with blue and red light.

PURPOSE: The kidney plays a central physiologic role as an oxygen sensor. Nevertheless, the direct mechanism by which this occurs is incompletely understood. We measured renal microvascular partial pressure of oxygen (PkO2) to determine the impact of clinically relevant conditions that acutely change PkO2 including hyperoxia and hemodilution. METHODS: We utilized two-wavelength excitation (red and blue spectrum) of the intravascular phosphorescent oxygen sensitive probe Oxyphor PdG4 to measure renal tissue PO2 in anesthetized rats (2% isoflurane, n = 6) under two conditions of altered arterial blood oxygen content (CaO2): 1) hyperoxia (fractional inspired oxygen 21%, 30%, and 50%) and 2) acute hemodilutional anemia (baseline, 25% and 50% acute hemodilution). The mean arterial blood pressure (MAP), rectal temperature, arterial blood gases (ABGs), and chemistry (radiometer) were measured under each condition. Blue and red light enabled measurement of PkO2 in the superficial renal cortex and deeper cortical and medullary tissue, respectively. RESULTS: PkO2 was higher in the superficial renal cortex (~ 60 mmHg, blue light) relative to the deeper renal cortex and outer medulla (~ 45 mmHg, red light). Hyperoxia resulted in a proportional increase in PkO2 values while hemodilution decreased microvascular PkO2 in a linear manner in both superficial and deeper regions of the kidney. In both cases (blue and red light), PkO2 correlated with CaO2 but not with MAP. CONCLUSION: The observed linear relationship between CaO2 and PkO2 shows the biological function of the kidney as a quantitative sensor of anemic hypoxia and hyperoxia. A better understanding of the impact of changes in PkO2 may inform clinical practices to improve renal oxygen delivery and prevent acute kidney injury.

RéSUMé: OBJECTIF: Les reins jouent un rôle physiologique central en tant que détecteurs d'oxygène. Cependant, le mécanisme direct de ce rôle n'est pas complètement compris. Nous avons mesuré la pression partielle d'oxygène microvasculaire rénal (PkO2) afin de déterminer l'impact de conditions pertinentes d'un point de vue clinique qui modifient de façon aiguë la PkO2, y compris l'hyperoxie et l'hémodilution. MéTHODE: Nous avons utilisé l'excitation à deux longueurs d'onde (spectres rouge et bleu) de la sonde phosphorescente, sensible à l'oxygène, intravasculaire Oxyphor PdG4 afin de mesurer la PO2 dans le tissu rénal de rats sous anesthésie (isoflurane 2 %, n = 6) dans deux conditions de contenu en oxygène du sang artériel (CaO2) altéré : 1) hyperoxie (fraction d'oxygène inspiré 21 %, 30 % et 50 %) et 2) anémie par hémodilution aiguë (valeurs de base, hémodilution aiguë 25 % et 50 %). La tension artérielle moyenne (TAM), la température rectale, les gaz sanguins artériels et la chimie (radiomètre) ont été mesurés dans chacune des conditions. Les lumières bleue et rouge ont permis de mesurer la PkO2 dans le cortex rénal superficiel et les tissus cortical et médullaire plus profonds, respectivement. RéSULTATS: La PkO2 était plus élevée dans le cortex rénal superficiel (~ 60 mmHg, lumière bleue) comparativement au cortex rénal plus profond et à la zone médullaire extérieure (~ 45 mmHg, lumière rouge). L'hyperoxie a entraîné une augmentation proportionnelle des valeurs de PkO2, alors que l'hémodilution a diminué la PkO2 microvasculaire de façon linéaire tant dans les régions rénales superficielles que plus profondes. Dans les deux cas (lumières bleue et rouge), la PkO2 était corrélée au CaO2 mais pas à la TAM. CONCLUSION: La relation linéaire observée entre le CaO2 et la PkO2 montre la fonction biologique du rein en tant que détecteur quantitatif de l'hypoxie anémique et de l'hyperoxie. Une meilleure compréhension de l'impact des changements de la PkO2 pourrait guider les pratiques cliniques afin d'améliorer la distribution d'oxygène aux reins et prévenir l'insuffisance rénale aiguë.

Effect of Empagliflozin on Left Ventricular Mass in Patients With Type 2 Diabetes Mellitus and Coronary Artery Disease: The EMPA-HEART CardioLink-6 Randomized Clinical Trial.

BACKGROUND: SGLT2 (sodium-glucose cotransporter 2) inhibitors lower cardiovascular events in type 2 diabetes mellitus but whether they promote direct cardiac effects remains unknown. We sought to determine if empagliflozin causes a decrease in left ventricular (LV) mass in people with type 2 diabetes mellitus and coronary artery disease. METHODS: Between November 2016 and April 2018, we recruited 97 individuals ≥40 and ≤80 years old with glycated hemoglobin 6.5% to 10.0%, known coronary artery disease, and estimated glomerular filtration rate ≥60mL/min/1.73m2. The participants were randomized to empagliflozin (10 mg/day, n=49) or placebo (n=48) for 6 months, in addition to standard of care. The primary outcome was the 6-month change in LV mass indexed to body surface area from baseline as measured by cardiac magnetic resonance imaging. Other measures included 6-month changes in LV end-diastolic and -systolic volumes indexed to body surface area, ejection fraction, 24-hour ambulatory blood pressure, hematocrit, and NT-proBNP (N-terminal pro b-type natriuretic peptide). RESULTS: Among the 97 participants (90 men [93%], mean [standard deviation] age 62.8 [9.0] years, type 2 diabetes mellitus duration 11.0 [8.2] years, estimated glomerular filtration rate 88.4 [16.9] mL/min/1.73m2, LV mass indexed to body surface area 60.7 [11.9] g/m2), 90 had evaluable imaging at follow-up. Mean LV mass indexed to body surface area regression over 6 months was 2.6 g/m2 and 0.01 g/m2 for those assigned empagliflozin and placebo, respectively (adjusted difference -3.35 g/m2; 95% CI, -5.9 to -0.81g/m2, P=0.01). In the empagliflozin-allocated group, there was significant lowering of overall ambulatory systolic blood pressure (adjusted difference -6.8mmHg, 95% CI -11.2 to -2.3mmHg, P=0.003), diastolic blood pressure (adjusted difference -3.2mmHg; 95% CI, -5.8 to -0.6mmHg, P=0.02) and elevation of hematocrit (P=0.0003). CONCLUSIONS: Among people with type 2 diabetes mellitus and coronary artery disease, SGLT2 inhibition with empagliflozin was associated with significant reduction in LV mass indexed to body surface area after 6 months, which may account in part for the beneficial cardiovascular outcomes observed in the EMPA-REG OUTCOME (BI 10773 [Empagliflozin] Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) trial. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02998970.

Renal tissue Po2 sensing during acute hemodilution is dependent on the diluent.

Sensing changes in blood oxygen content ([Formula: see text]) is an important physiological role of the kidney; however, the mechanism(s) by which the kidneys sense and respond to changes in [Formula: see text] are incompletely understood. Accurate measurements of kidney tissue oxygen tension ([Formula: see text]) may increase our understanding of renal oxygen-sensing mechanisms and could inform decisions regarding the optimal fluid for intravascular volume resuscitation to maintain renal perfusion. In some clinical settings, starch solution may be nephrotoxic, possibly due to inadequacy of tissue oxygen delivery. We hypothesized that hemodilution with starch colloid solutions would reduce [Formula: see text] to a more severe degree than other diluents. Anesthetized Sprague-Dawley rats (n = 77) were randomized to undergo hemodilution with either colloid (6% hydroxyethyl starch or 5% albumin), crystalloid (0.9% saline), or a sham procedure (control) (n = 13-18 rats/group). Data were analyzed by ANOVA with significance assigned at P < 0.05. After hemodilution, mean arterial pressure (MAP) decreased marginally in all groups, while hemoglobin (Hb) and [Formula: see text] decreased in proportion to the degree of hemodilution. Cardiac output was maintained in all groups after hemodilution. [Formula: see text] decreased in proportion to the reduction in Hb in all treatment groups. At comparably reduced Hb, and maintained arterial oxygen values, hemodilution with starch resulted in larger decreases in [Formula: see text] relative to animals hemodiluted with albumin or saline (P < 0.008). Renal medullary erythropoietin (EPO) mRNA levels increased more prominently, relative to other hypoxia-regulated molecules (GLUT-1, GAPDH, and VEGF). Our data demonstrate that the kidney acts as a biosensor of reduced [Formula: see text] following hemodilution and that [Formula: see text] may provide a quantitative signal for renal cellular responsiveness to acute anemia. Evidence of a more severe reduction in [Formula: see text] following hemodilution with starch colloid solution suggests that tissue hypoxia may contribute to starch induced renal toxicity.

Load-independent effects of empagliflozin contribute to improved cardiac function in experimental heart failure with reduced ejection fraction.

BACKGROUND AND AIMS: Sodium-glucose linked cotransporter-2 (SGLT2) inhibitors reduce the likelihood of hospitalization for heart failure and cardiovascular death in both diabetic and non-diabetic individuals with reduced ejection fraction heart failure. Because SGLT2 inhibitors lead to volume contraction with reductions in both preload and afterload, these load-dependent factors are thought to be major contributors to the cardioprotective effects of the drug class. Beyond these effects, we hypothesized that SGLT2 inhibitors may also improve intrinsic cardiac function, independent of loading conditions. METHODS: Pressure-volume (P-V) relationship analysis was used to elucidate changes in intrinsic cardiac function, independent of alterations in loading conditions in animals with experimental myocardial infarction, a well-established model of HFrEF. Ten-week old, non-diabetic Fischer F344 rats underwent ligation of the left anterior descending (LAD) coronary artery to induce myocardial infarction (MI) of the left ventricle (LV). Following confirmation of infarct size with echocardiography 1-week post MI, animals were randomized to receive vehicle, or the SGLT2 inhibitor, empagliflozin. Cardiac function was assessed by conductance catheterization just prior to termination 6 weeks later. RESULTS: The circumferential extent of MI in animals that were subsequently randomized to vehicle or empagliflozin groups was similar. Empagliflozin did not affect fractional shortening (FS) as assessed by echocardiography. In contrast, load-insensitive measures of cardiac function were substantially improved with empagliflozin. Load-independent measures of cardiac contractility, preload recruitable stroke work (PRSW) and end-systolic pressure volume relationship (ESPVR) were higher in rats that had received empagliflozin. Consistent with enhanced cardiac performance in the heart failure setting, systolic blood pressure (SBP) was higher in rats that had received empagliflozin despite its diuretic effects. A trend to improved diastolic function, as evidenced by reduction in left ventricular end-diastolic pressure (LVEDP) was also seen with empagliflozin. MI animals treated with vehicle demonstrated myocyte hypertrophy, interstitial fibrosis and evidence for changes in key calcium handling proteins (all p < 0.05) that were not affected by empagliflozin therapy. CONCLUSION: Empagliflozin therapy improves cardiac function independent of loading conditions. These findings suggest that its salutary effects are, at least in part, due to actions beyond a direct effect of reduced preload and afterload.

Comparison of Ligation of the Intersphincteric Fistula Tract and BioLIFT for the Treatment of Transsphincteric Anal Fistula: A Retrospective Analysis.

BACKGROUND: Ligation of the intersphincteric fistula tract is a sphincter-preserving technique for the treatment of anal fistulas. The BioLIFT modification involves the placement of a biologic mesh in the intersphincteric plane. Advocates of this modification state improved healing rates, however evidence for this is lacking, and this approach costs significantly more. OBJECTIVE: The purpose of this study was to compare the healing rates of the ligation of the intersphincteric fistula tract with the BioLIFT. DESIGN: This was a retrospective cohort study. SETTINGS: The study was conducted at a tertiary care hospital from April 2008 to April 2018. PATIENTS: All adult patients with transsphincteric anal fistulas were included. Patients were excluded if they had IBD, more than 1 fistula tract operated on simultaneously, or a previous attempt at repair. MAIN OUTCOME MEASURES: The primary outcome was primary healing of the fistula tract, and secondary outcomes included overall success, complications, and time to recurrence. RESULTS: There were 119 cases (75 ligation of the intersphincteric fistula tract and 44 BioLIFTs). One surgeon performed 84% of the BioLIFT cases. The primary healing rate was 75.0% versus 58.7% (p = 0.08), and the complication rate was 22.7% versus 17.3% (p = 0.48; BioLIFT vs ligation of intersphincteric fistula tract). After multivariate logistic regression, the BioLIFT had a significantly better healing rate (OR = 2.38 (95% CI, 1.01-5.62); p = 0.048). Median follow-up was 9 versus 29 weeks (BioLIFT vs ligation of intersphincteric fistula tract). Kaplan-Meier analysis demonstrated no difference in the time to recurrence (p = 0.48). LIMITATIONS: This study was limited by the retrospective nature, different lengths of follow-up, and varying case numbers between the surgeons. CONCLUSIONS: The BioLIFT modification is safe and effective for the treatment of anal fistulas but has a higher cost. This modification warrants additional prospective studies to establish its benefits over the ligation of the intersphincteric fistula tract procedure. See Video Abstract at http://links.lww.com/DCR/B139. COMPARACIÓN DE LIFT VERSUS BIOLIFT PARA EL TRATAMIENTO DE LA FÍSTULA ANAL TRANSFINTERÉRICA: UN ANÁLISIS RETROSPECTIVO: Ligadura del tracto de la fístula interesfintérica es una técnica para preservación del esfínter en el tratamiento de las fístulas anales. La modificación BioLIFT implica la colocación de una malla biológica en el plano interesfintérico. Protagonistas de la modificación mejoraron las tasas de curación, sin embargo, carecen evidencias definitivas y la técnica eleva costos significativamente.Comparar las tasas de curación de ligadura del tracto de la fístula interesfintérica con el BioLIFT.Estudio de cohorte retrospectivo.Hospital de atención de tercer nivel desde abril de 2008 hasta abril de 2018.Se incluyeron todos los pacientes adultos con fístulas anales transfinteréricas. Los pacientes fueron excluidos si tenían enfermedad inflamatoria intestinal, más de un tracto fistuloso operado simultáneamente o con un intento previo de reparación.El resultado principal fue la curación primaria del tracto fistuloso y los resultados secundarios incluyeron el éxito en general, las complicaciones y tiempo hasta recurrencia.Se registraron 119 casos (75 ligaduras del tracto de la fístula interesfintérica y 44 BioLIFT). Un cirujano realizó el 84% de los casos de BioLIFT. La tasa de curación primaria fue del 75.0% vs 58.7%, p = 0.08, y la tasa de complicaciones fue del 22.7% vs 17.3%, p = 0.48 comparando BioLIFT vs ligadura del tracto de la fístula interesfintérica. Después de la regresión logística multivariada, el BioLIFT tuvo una tasa de curación significativamente mejor (OR 2.38 [IC 95% 1.01-5.62], p = 0.048). La mediana de seguimiento fue de 9 vs 29 semanas (BioLIFT vs ligadura del tracto de la fístula interesfintérica). El análisis de Kaplan-Meier no demostró diferencias en el tiempo hasta la recurrencia (p = 0,48).Este estudio estuvo limitado por ser retrospectivo, las diferentes duraciones de seguimiento y el número variable de casos entre los cirujanos.La modificación BioLIFT es segura y efectiva para el tratamiento de las fístulas anales pero tiene un costo más alto. Esta modificación amerita más estudios prospectivos para establecer los beneficios sobre ligadura del tracto de la fístula interesfintérica. Consulte Video Resumen en hhttp://links.lww.com/DCR/B139.

Renal histology in diabetic nephropathy predicts progression to end-stage kidney disease but not the rate of renal function decline.

BACKGROUND: While histopathologic changes correlate with functional impairment in cross-sectional studies of diabetic nephropathy (DN), whether these findings predict future rate of kidney function loss remains uncertain. We thus sought to examine the relationship between kidney histopathology, incidence of end-stage kidney disease (ESKD), and rate of estimated glomerular filtration rate (eGFR) loss in DN. METHODS: In this longitudinal cohort study, we studied 50 adults diagnosed with biopsy-proven DN. We analyzed the histopathologic parameters of each patient's kidney biopsy, as defined by the Renal Pathology Society classification system for DN, and tracked all available eGFR measurements post-biopsy. We additionally collected baseline clinical parameters (at the time of biopsy), including eGFR, albumin-to-creatinine ratio (ACR), and hemoglobin A1c. Multivariable linear regression was used to assess the relationship between histologic and clinical parameters at the time of the biopsy and eGFR slope. Kaplan-Meier curves and Cox regression were used to evaluate the association between histologic and clinical parameters and ESKD incidence. RESULTS: Progression to ESKD was associated with worsening interstitial fibrosis score (p = 0.05), lower baseline eGFR (p = 0.02), higher ACR (p = 0.001), and faster eGFR decline (p < 0.001). The rate of eGFR decline did not associate with any histologic parameter. Baseline ACR was the only studied variable correlating with eGFR slope (rho = - 0.41). CONCLUSIONS: Renal histology predicts ultimate progression to ESKD, but not the rate of progression. Future work is required to identify novel predictors of rapid functional decline in patients with diabetic nephropathy.

The safety and efficacy of hypovolemic phlebotomy on blood loss and transfusion in liver surgery: a systematic review and meta-analysis.

BACKGROUND: Hypovolemic phlebotomy (HP) is a novel intervention that involves intraoperative removal of whole blood (7-10 mL/kg) without volume replacement. The subsequent central venous pressure (CVP) reduction is hypothesized to decrease blood loss and the need for blood transfusion. The objective was to conduct a systematic assessment of the safety and efficacy of HP on blood loss and transfusion in the liver surgery literature. METHODS: MEDLINE, EMBASE, and Cochrane Library databases were searched. Outcomes of interest included blood loss, allogenic red blood cell transfusion, postoperative adverse events, and CVP change. A qualitative synthesis and meta-analysis were performed as appropriate. RESULTS: Four cohort studies, one case series, and three randomized controlled trials involving 2255 patients were included. Meta-analysis of studies involving liver resections for any indication (n = 6) found no difference in transfusion (OR 0.38, p = 0.12) or incidence of adverse events with HP compared to non-use. Pooling of studies involving liver resections for an underlying pathology (n = 4) revealed HP was associated with significant reduction in transfusion (OR 0.25, p = 0.03) but no differences in blood loss (-173 mL, p = 0.17). CONCLUSION: This review suggests HP is safe and associated with decreased transfusion in patients undergoing liver surgery. It supports further investigation.

Ablation of the calpain-targeted site in cardiac myosin binding protein-C is cardioprotective during ischemia-reperfusion injury.

Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is essential for normal heart function and protects the heart from ischemia-reperfusion (I/R) injury. It is known that protein kinase-A (PKA)-mediated phosphorylation of cMyBP-C prevents I/R-dependent proteolysis, whereas dephosphorylation of cMyBP-C at PKA sites correlates with its degradation. While sites on cMyBP-C associated with phosphorylation and proteolysis co-localize, the mechanisms that link cMyBP-C phosphorylation and proteolysis during cardioprotection are not well understood. Therefore, we aimed to determine if abrogation of cMyBP-C proteolysis in association with calpain, a calcium-activated protease, confers cardioprotection during I/R injury. Calpain is activated in both human ischemic heart samples and ischemic mouse myocardium where cMyBP-C is dephosphorylated and undergoes proteolysis. Moreover, cMyBP-C is a substrate for calpain proteolysis and cleaved by calpain at residues 272-TSLAGAGRR-280, a domain termed as the calpain-target site (CTS). Cardiac-specific transgenic (Tg) mice in which the CTS motif was ablated were bred into a cMyBP-C null background. These Tg mice were conclusively shown to possess a normal basal structure and function by analysis of histology, electron microscopy, immunofluorescence microscopy, Q-space MRI of tissue architecture, echocardiography, and hemodynamics. However, the genetic ablation of the CTS motif conferred resistance to calpain-mediated proteolysis of cMyBP-C. Following I/R injury, the loss of the CTS reduced infarct size compared to non-transgenic controls. Collectively, these findings demonstrate the physiological significance of calpain-targeted cMyBP-C proteolysis and provide a rationale for studying inhibition of calpain-mediated proteolysis of cMyBP-C as a therapeutic target for cardioprotection.