An incoherent Thomson scattering system for measurements near plasma boundaries.

Laser Thomson scattering (LTS) is a minimally invasive measurement technique used for determining electron properties in plasma systems. Sheath model closure validation requires minimally invasive measurements of the electron properties that traverse the boundaries between the bulk plasma, the presheath, and the plasma sheath. Several studies have probed the radial properties along the surface of discharge electrodes with laser-based diagnostics and electrostatic probes. These measurements provide valuable insight into the electron properties in this dynamic region. However, sheath model calibration requires plasma property measurements perpendicular to plasma bounding surfaces, in this case, along the electrode normal vector between discharge electrodes. This work presents the development of a discharge plasma cell and laser Thomson scattering system with a measurement volume step of 1 mm normal to plasma bounding surfaces. The laser Thomson scattering measurements are made between a set of discharge electrodes separated by ∼25 mm that are used to generate a pulsed argon plasma. The spatial distribution of electron temperature and density is measured at several discharge voltages between 8 and 20 kV at a pressure of 8 Torr-Ar. It is determined that the system is statistically stationary and resembles a classic DC discharge plasma. The results are some of the first laser diagnostic-based "between electrode" measurements made along the plasma bounding electrode normal vector. A one-dimensional sheath model is applied to determine the near cathode electron properties, and it is determined that the edge of the presheath is probed in the high-voltage cases. As the lengths of the presheath and sheath decrease with decreasing voltage, the region recedes below the closest probed point to the cathode. To improve the performance of the diagnostic, the step size of the interrogation volume should decrease by an order of magnitude from 1 mm to less than 100 µm, and the data acquisition strategy should be revised to increase the signal-to-noise ratio.

Integrating lesbian, gay, bisexual, transgender, and queer (LGBTQ) competency into the dental school curriculum.

BACKGROUND: Decreasing healthcare disparities in marginalized communities requires healthcare providers who understand and appreciate social, economic, and cultural backgrounds. This includes care and education focused on individuals who identify as lesbian, gay, bisexual, transgender, or queer (LGBTQ). METHODS: This study examined dental students' and residents' self-reported clinical preparedness, prejudicial attitudes (implicit and explicit), and knowledge of health disparities that exist in the LGBTQ community using the Lesbian, Gay, Bisexual, Transgender Development of Clinical Skills Scale (LGBT-DOCSS) prior to and after the presentation of an LGBTQ competency course. RESULTS: A total of 178 dental students at a private US dental school ranging from D1 to first-year postdoctoral residency participated in the course and completed both pre-course survey and post-course survey. Sixty-seven percent of the students reported having formal training in LGBTQ competency prior to completing the pre-training survey. The results of the LGBT-DOCSS in this population following intervention training revealed an increased feeling of clinical preparedness in treating LGBTQ patients, decreased bias toward LGBTQ, and increased knowledge of health disparities in the LGBTQ community. A more significant percentage of male respondents self-reported prejudicial beliefs. Knowledge of LGBTQ health issues increased significantly among pre-clinical students. CONCLUSION: Introducing an early intervention LGBTQ competency course in the dental curriculum is an effective method of improving students' awareness and self-confidence in working with LGBTQ patients while decreasing biases that may have existed prior to a training course.

Resolution of Cardiac Infiltration Following Autologous Stem Cell Transplantation for AL Amyloidosis.

A 43-year-old man presented with severe heart failure secondary to high-risk light chain cardiac amyloidosis. He underwent chemotherapy and autologous stem cell transplantation with complete hematologic response. Serial cardiac magnetic resonance imaging post-transplant demonstrated gradual normalization of biventricular function and myocardial T1, a surrogate measure of disease burden.

Transcatheter Aortic Valve Implantation in a Failed Perceval Sutureless Valve, Complicated by Aortic Annular Rupture.

As the use of surgically implanted sutureless aortic valves has increased over the past decade, we expect to encounter their failure increasingly in coming years. We describe a case of Perceval aortic valve failure with stent infolding and severe stenosis. This condition was treated with valve-in-valve transcatheter aortic valve implantation and complicated by aortic annular rupture at the site of infolding. This case is important because it outlines the limited experience with valve-in-valve transcatheter aortic valve implantation to treat failed sutureless valves and identifies sutureless valve infolding as a potential risk for annular rupture.

Puisque l'implantation valvulaire aortique sans suture s'est accrue au cours de la dernière décennie, nous nous attendons à rencontrer de plus en plus de défaillances de valves dans les années à venir. Nous décrivons un cas de défaillance de la valve aortique Perceval avec pliage de l'endoprothèse et sténose grave. Le traitement qui consistait en l'implantation valvulaire aortique de type valve-in-valve par cathéter a été compliqué par la rupture de l'anneau aortique au site du pliage. Il s'agit d'un cas important puisqu'il décrit le peu d'expérience en matière d'implantation valvulaire aortique de type valve-in-valve par cathéter dans le traitement des valves sans suture défectueuses et établit que le pliage d'une valve sans suture expose à un risque de rupture de l'anneau.

Normalized Subendocardial Myocardial Attenuation on Coronary Computed Tomography Angiography Predicts Postoperative Adverse Cardiovascular Events: Coronary CTA VISION Substudy.

BACKGROUND: Abnormalities in computed tomography myocardial perfusion has been associated with coronary artery disease and major adverse cardiovascular events (MACE). We sought to investigate if subendocardial attenuation using coronary computed tomography angiography predicts MACE 30 days postelective noncardiac surgery. METHODS: Using a 17-segment model, coronary computed tomography angiography images were analyzed for subendocardial and transmural attenuation and the corresponding blood pool. The segment with the lowest subendocardial attenuation and transmural attenuation were normalized to the segment with the highest subendocardial and transmural attenuation, respectively (SUBnormalized, and TRANSnormalized, respectively). We evaluated the independent and incremental value of myocardial attenuation to predict the composite of cardiovascular death or nonfatal myocardial infarction. RESULTS: Of a total of 995 coronary CTA VISION (Coronary Computed Tomographic Angiography and Vascular Events in Noncardiac Surgery Patients Cohort Evaluation Study) patients, 735 had available images and complete data for these analyses. Among these patients, 60 had MACE. Based on Revised Cardiovascular Risk Index, 257, 302, 138, and 38 patients had scores of 0, 1, 2, and ≥3, respectively. On coronary computed tomography angiography, 75 patients had normal coronary arteries, 297 patients had nonobstructive coronary artery disease, 264 patients had obstructive disease, and 99 patients had extensive obstructive coronary artery disease. SUBnormalized was an independent and incremental predictor of events in the model that included Revised Cardiovascular Risk Index and coronary artery disease severity. Compared with patients in the highest tertile of SUBnormalized, patients in the second and first tertiles had an increased hazards ratio for events (2.23 [95% CI, 1.091-4.551] and 2.36 [95% CI, 1.16-4.81], respectively). TRANSnormalized, as a continuous variable, was also found to be a predictor of MACE (P=0.027). CONCLUSIONS: Our study demonstrates that SUBnormalized and TRANSnormalized are independent and incremental predictors of MACE 30 days after elective noncardiac surgery. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01635309.

2021 Update on Safety of Magnetic Resonance Imaging: Joint Statement From Canadian Cardiovascular Society/Canadian Society for Cardiovascular Magnetic Resonance/Canadian Heart Rhythm Society.

Magnetic resonance imaging (MRI) is often considered the gold-standard test for characterizing cardiac as well as noncardiac structure and function. However, many patients with cardiac implantable electronic devices (CIEDs) and/or severe renal dysfunction are unable to undergo this test because of safety concerns. In the past 10 years, newer-generation CIEDs and gadolinium-based contrast agents (GBCAs) as well as coordinated care between imaging and heart rhythm device teams have mitigated risk to patients and improved access to MRI at many hospitals. The purpose of this statement is to review published data on safety of MRI in patients with conditional and nonconditional CIEDs in addition to patient risks from older and newer GBCAs. This statement was developed through multidisciplinary collaboration of pan-Canadian experts after a relevant and independent literature search by the Canadian Agency for Drugs and Technologies in Health. All recommendations align with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Key recommendations include: (1) the development of standardized protocols for patients with a CIED undergoing MRI; (2) patients with MRI nonconditional pacemakers and pacemaker dependency should be programmed to asynchronous mode and those with MRI nonconditional transvenous defibrillators should have tachycardia therapies turned off during the scan; and (3) macrocyclic or newer linear GBCAs should be used in preference to older GBCAs because of their better safety profile in patients at higher risk of nephrogenic systemic fibrosis.

2021 update on safety of magnetic resonance imaging: joint statement from Canadian Cardiovascular Society/ Canadian Society for Cardiovascular Magnetic Resonance/ Canadian Heart Rhythm Society

Magnetic resonance imaging (MRI) is often considered the gold-standard test for characterizing cardiac as well as noncardiac structure and function. However, many patients with cardiac implantable electronic devices (CIEDs) and/or severe renal dysfunction are unable to undergo this test because of safety concerns. In the past 10 years, newer-generation CIEDs and gadolinium-based contrast agents (GBCAs) as well as coordinated care between imaging and heart rhythm device teams have mitigated risk to patients and improved access to MRI at many hospitals. The purpose of this statement is to review published data on safety of MRI in patients with conditional and nonconditional CIEDs in addition to patient risks from older and newer GBCAs. This statement was developed through multidisciplinary collaboration of pan-Canadian experts after a relevant and independent literature search by the Canadian Agency for Drugs and Technologies in Health. All recommendations align with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Key recommendations include: (1) the development of standardized protocols for patients with a CIED undergoing MRI; (2) patients with MRI nonconditional pacemakers and pacemaker dependency should be programmed to asynchronous mode and those with MRI nonconditional transvenous defibrillators should have tachycardia therapies turned off during the scan; and (3) macrocyclic or newer linear GBCAs should be used in preference to older GBCAs because of their better safety profile in patients at higher risk of nephrogenic systemic fibrosis.

Effects of Transcatheter Aortic Valve Implantation on Frailty and Quality of Life.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an effective alternative to surgical valve replacement in high-risk patients with severe aortic stenosis. Although measures of frailty have been used to attempt to predict outcomes in this population, few studies have demonstrated changes in these measures. METHODS: We performed a prospective, observational study of 171 patients undergoing TAVI, of whom 44 had maximal follow-up of 1 month and 50 had maximal follow-up of 1 year. Quality of life was assessed using the Minnesota Living With Heart Failure Questionnaire, Katz Index of Independence in Activities of Daily Living questionnaire, and patient perception of overall well-being. Frailty was measured using the 10-m walk test and handgrip strength testing. RESULTS: In the overall cohort, participants demonstrated improvements in quality of life metrics, but deterioration in 10-m walk test and handgrip at 1 month. These trends continued at 1 year. However, patients in the lowest quintile of handgrip and 10-m walk test demonstrated a trend of improvements in these metrics during follow-up. CONCLUSIONS: Despite improvements in quality of life after TAVI, no improvements in frailty were observed in patients at 1 year.

CONTEXTE: Le remplacement valvulaire aortique par cathéter (TAVI) est une solution de rechange efficace à la chirurgie de remplacement valvulaire chez les patients atteints de sténose aortique grave et présentant un risque élevé. Les mesures de la fragilité sont utilisées pour tenter de prévoir les résultats au sein de cette population. Néanmoins, peu d'études ont permis d'objectiver les variations de ces mesures. MÉTHODOLOGIE: Nous avons réalisé une étude observationnelle prospective portant sur 171 patients ayant subi un TAVI, dont 44 suivis pendant un mois ou moins, et 50 durant un an ou moins. La qualité de vie a été évaluée au moyen de questionnaires ­ Minnesota Living With Heart Failure Questionnaire et Katz Index of Independence in Activities of Daily Living Questionnaire ­ et en fonction de la perception du patient relativement à son bien-être général. La fragilité a été mesurée à l'aide d'un test de marche sur dix mètres et d'un test de force de préhension. RÉSULTATS: Dans l'ensemble de la cohorte, une amélioration des mesures de la qualité de vie a été observée parallèlement à une détérioration des résultats au test de marche sur dix mètres et au test de force de préhension après un mois. Les tendances à cet égard se sont poursuivies au bout d'un an. Cependant, les résultats des patients du quintile inférieur au test de marche sur 10 m et au test de force de préhension ont eu tendance à s'améliorer au cours de la période de suivi. CONCLUSIONS: Malgré une amélioration de la qualité de vie après le TAVI, la fragilité des patients ne s'est nullement améliorée après un an.

Relationship between Perioperative Hypotension and Perioperative Cardiovascular Events in Patients with Coronary Artery Disease Undergoing Major Noncardiac Surgery.

BACKGROUND: Perioperative hypotension is associated with cardiovascular events in patients having noncardiac surgery. It is unknown if the severity of preexisting coronary artery disease determines susceptibility to the cardiovascular risks of perioperative hypotension. METHODS: In this retrospective exploratory analysis of a substudy of an international prospective blinded cohort study, 955 patients 45 yr of age or older with history or risk factors for coronary artery disease underwent coronary computed tomographic angiography before elective inpatient noncardiac surgery. The authors evaluated the potential interaction between angiographic findings and perioperative hypotension (defined as systolic blood pressure less than 90 mmHg for a total of 10 min or more during surgery or for any duration after surgery and for which intervention was initiated) on the composite outcome of time to myocardial infarction or cardiovascular death up to 30 days after surgery. Angiography assessors were blinded to study outcomes; patients, treating clinicians, and outcome assessors were blinded to angiography findings. RESULTS: Cardiovascular events (myocardial infarction or cardiovascular death within 30 days after surgery) occurred in 7.7% of patients (74/955), including in 2.7% (8/293) without obstructive coronary disease or hypotension compared to 6.7% (21/314) with obstructive coronary disease but no hypotension (hazard ratio, 2.51; 95% CI, 1.11 to 5.66; P = 0.027), 8.8% (14/159) in patients with hypotension but without obstructive coronary disease (hazard ratio, 3.85; 95% CI, 1.62 to 9.19; P = 0.002), and 16.4% (31/189) with obstructive coronary disease and hypotension (hazard ratio, 7.34; 95% CI, 3.37 to 15.96; P < 0.001). Hypotension was independently associated with cardiovascular events (hazard ratio, 3.17; 95% CI, 1.99 to 5.06; P < 0.001). This association remained in patients without obstructive disease and did not differ significantly across degrees of coronary disease (P value for interaction, 0.599). CONCLUSIONS: In patients having noncardiac surgery, perioperative hypotension was associated with cardiovascular events regardless of the degree of coronary artery disease on preoperative coronary computed tomographic angiography.

Variables Associated With Cardiac Surgical Waitlist Mortality From a Population-Based Cohort.

BACKGROUND: Cardiac surgery waitlist recommendations, which were developed based on expert opinion, poorly predict preoperative mortality. Studies reporting risk factors for waitlist mortality have not evaluated the risks including nonadherence to waitlist benchmarks. METHODS: In patients who underwent cardiac surgery or died on the waitlist between 2005 and 2015, we used a Fine and Gray competing risk model to identify independent predictors of waitlist mortality in 12,106 patients scheduled for urgent, semiurgent, or nonurgent surgery. The predictive variables were compared with Canadian Cardiovascular Society (CCS) waitlist recommendations using the Akaike information criterion. RESULTS: A total of 101 (0.8%) patients died awaiting surgery. The median wait times and frequency waitlist deaths among emergent, urgent, semi-urgent, and nonurgent surgery were 0.6, 7.4, 69.0, 55.5 days (P < 0.001) and 6.3%, 0.8%, 0.3%, 0.6% (P < 0.001), respectively. Adherence to CCS waitlist recommendations was higher in patients who died on the waitlist (51.6% vs 70.8%, P = 0.001) and was not predictive of waitlist mortality (hazard ratio 1.48, 95% confidence interval 0.62-0.56). Independent predictors of waitlist mortality were age, aortic surgery, ejection fraction < 35%, urgent surgery, prior myocardial infarction, haemodynamic instability during cardiac catheterization, hypertension, and dyslipidemia. These variables were superior to current CCS guidelines (Akaike information criterion 1251 vs 1317, likelihood ratio test P < 0.001). CONCLUSIONS: CCS waitlist recommendations were poorly predictive of waitlist mortality and the majority of waitlist deaths occur within recommended benchmarks. We identified variables associated with waitlist mortality with improved clinical performance. Our findings suggest a need to re-evaluate cardiac surgical triage criteria using evidence-based data.

Impact of contrast echocardiography on accurate discrimination of specific degree of left ventricular systolic dysfunction and comparison with cardiac magnetic resonance imaging.

AIM: Limited data exist on the impact of contrast-enhanced echocardiography on treatment decisions in heart failure patients that require specific left ventricular ejection fraction (LVEF) criteria. This study assessed accuracy of contrast-enhanced echocardiography in identifying patients with LVEF >35% vs ≤35% with cardiac magnetic resonance (CMR) used as reference method. METHODS AND RESULTS: Fifty-five patients from prospective Alberta HEART cohort with LVEF ≤50% on CMR were included. All patients had echocardiography performed within 2 weeks of CMR. Contrast agent was used when ≥2 contiguous LV endocardial segments were poorly visualized on echocardiography. LVEF was computed by Simpson's biplane method using non-contrast echocardiography and contrast-enhanced echocardiography and by outlining the endocardial contours in short-axis cine CMR images. Strong agreement in LV volumes and LVEF was seen between CMR and echocardiography with and without contrast (intra-class correlation coefficients >0.8) with less underestimation of LV volumes by contrast-enhanced echocardiography. Good agreement in LVEF ≤35% vs >35% was seen between CMR and non-contrast echocardiography with optimal images (κ 0.862) and contrast echocardiography (κ 0.769) while it was moderate for non-contrast echocardiography with suboptimal images (κ 0.491). The use of LV contrast in patients with suboptimal images (n = 39) resulted in correctly upgrading LVEF from ≤35% to >35% in 5 (13%) patients and downgrading LVEF from >35% to ≤35% in 2 (5%) patients using CMR as reference. CONCLUSIONS: Contrast-enhanced echocardiography in heart failure patients with suboptimal images helps to more accurately assess eligibility for specific therapies and avoid need for further testing, therefore should be considered routine part of echocardiographic assessment.

Does the virtual refractor patient-simulator improve student competency when refracting in the consulting room?

BACKGROUND: The use of patient simulators in ophthalmic education appears limited. This study examines the effects of the addition of the 'Virtual Refractor' patient simulator learning activity into a short unit preparing students to determine the power of the spectacle lenses required by patients in a clinic. METHODS: Twenty-four year one optometry students were randomly assigned to either the simulator-intervention group (n = 12) or the non-intervention group. All students attended tutorials on refraction and the use of a refractor-head. Simulator-intervention students additionally attended a tutorial on the Virtual Refractor. All answered a questionnaire concerning time spent studying, perceived knowledge and confidence. Twenty-four short-sighted patients were recruited. Two refractions per student were timed and the accuracy compared with that of an experienced optometrist. RESULTS: Ten students from each group completed the study. Students who used the simulator were significantly (p < 0.05) more accurate at a clinical level (within 0.22 ± 0.22 DS, 95 per cent CI 0.12-0.32) than those who did not (within 0.60 ± 0.67 DS, 95 per cent CI 0.29-0.92) and 13 per cent quicker (4.7 minutes, p < 0.05). Students who used the simulator felt more knowledgeable (p < 0.05) and confident (p < 0.05), but had spent more time reading about refraction and practised on the Virtual Refractor at home for 5.7 ± 1.3 hours. CONCLUSION: The Virtual Refractor has many features of high-fidelity medical simulation known to lead to effective learning and it also offers flexible independent learning without a concomitant increase in the student time-burden. The improved accuracy and speed on first patient encounters found in this study validates the use of this patient simulator as a useful bridge for students early in training to successfully transfer theoretical knowledge prior to entering the consulting room. The translational benefits resulting from compulsory learning activities on a patient simulator can lead to reduced demands on infrastructure and clinical supervision.

Comparison of epicardial adipose tissue radiodensity threshold between contrast and non-contrast enhanced computed tomography scans: A cohort study of derivation and validation.

BACKGROUND AND AIMS: Epicardial adipose tissue (EAT) volume derived from contrast enhanced (CE) computed tomography (CT) scans is not well validated. We aim to establish a reliable threshold to accurately quantify EAT volume from CE datasets. METHODS: We analyzed EAT volume on paired non-contrast (NC) and CE datasets from 25 patients to derive appropriate Hounsfield (HU) cutpoints to equalize two EAT volume estimates. The gold standard threshold (-190HU, -30HU) was used to assess EAT volume on NC datasets. For CE datasets, EAT volumes were estimated using three previously reported thresholds: (-190HU, -30HU), (-190HU, -15HU), (-175HU, -15HU) and were analyzed by a semi-automated 3D Fat analysis software. Subsequently, we applied a threshold correction to (-190HU, -30HU) based on mean differences in radiodensity between NC and CE images (ΔEATrd = CE radiodensity - NC radiodensity). We then validated our findings on EAT threshold in 21 additional patients with paired CT datasets. RESULTS: EAT volume from CE datasets using previously published thresholds consistently underestimated EAT volume from NC dataset standard by a magnitude of 8.2%-19.1%. Using our corrected threshold (-190HU, -3HU) in CE datasets yielded statistically identical EAT volume to NC EAT volume in the validation cohort (186.1 ±â€¯80.3 vs. 185.5 ±â€¯80.1 cm3, Δ = 0.6 cm3, 0.3%, p = 0.374). CONCLUSIONS: Estimating EAT volume from contrast enhanced CT scans using a corrected threshold of -190HU, -3HU provided excellent agreement with EAT volume from non-contrast CT scans using a standard threshold of -190HU, -30HU.

Late presentation of an anomalous left coronary artery from the pulmonary artery treated with conservative surgical management with long-term cardiac magnetic resonance imaging follow-up.

Anomalous origin of the left coronary artery from the pulmonary artery is rare congenital abnormality that most commonly presents in childhood and is associated with a high mortality. In the elderly, patients may present acutely with arrhythmias or signs of ischemia or with vague chronic presentations of shortness of breath and fatigue. In the high-risk elderly population, it is unclear as to whether conservative surgical management by means of suture ligation of the left coronary artery is associated with positive long-term outcomes. We present a case of a 69-year-old patient diagnosed with anomalous origin of the left coronary artery from the pulmonary artery, which was treated with conservative surgical management and followed up for 15 years with cardiovascular magnetic resonance imaging, with positive outcomes.

Transcatheter Valve-in-Valve: A Cautionary Tale.

Transcatheter aortic valve replacement (TAVR) by valve-in-valve (VIV) implantation is an alternative treatment for high-risk patients with a degenerating aortic bioprosthesis. We present a case of transapical TAVR VIV with a 29-mm Edwards SAPIEN XT (ESV) (Edwards Lifesciences, Irvine, CA) into a 29-mm Medtronic Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, MN) in which unanticipated dilatation of the Freestyle bioprosthesis resulted in intraprocedural embolization of the TAVR valve, necessitating urgent conversion to a conventional surgical aortic valve replacement (AVR). Our experience suggests that TAVR VIV with the 29-mm ESV in the setting of a degenerated 29-mm Freestyle stentless bioprosthesis must be undertaken with caution.