Clinical validation of C12FDG as a marker associated with senescence and osteoarthritic phenotypes

Chronic conditions associated with aging have proven difficult to prevent or treat. Senescence is a cell fate defined by loss of proliferative capacity and the development of a pro-inflammatory senescence-associated secretory phenotype comprised of cytokines/chemokines, proteases, and other factors that promotes age-related diseases. Specifically, an increase in senescent peripheral blood mononuclear cells (PBMCs), including T cells, is associated with conditions like frailty, rheumatoid arthritis, and bone loss. However, it is unknown if the percentage of senescent PBMCs associated with age-associated orthopedic decline could be used for potential diagnostic or prognostic use in orthopedics. Here, we report senescent cell detection using the fluorescent compound C12FDG to quantify PBMCs senescence across a large cohort of healthy and osteoarthritic patients. There is an increase in the percent of circulating C12FDG+ PBMCs that is commensurate with increases in age and senescence-related serum biomarkers. Interestingly, C12FDG+ PBMCs and T cells also were found to be elevated in patients with mild to moderate osteoarthritis, a progressive joint disease that is strongly associated with inflammation. The percent of C12FDG+ PBMCs and age-related serum biomarkers were decreased in a small subgroup of study participants taking the senolytic drug fisetin. These results demonstrate quantifiable measurements in a large group of participants that could create a composite score of healthy aging sensitive enough to detect changes following senolytic therapy and may predict age-related orthopedic decline. Detection of peripheral senescence in PBMCs and subsets using C12FDG may be clinically useful for quantifying cellular senescence and determining how and if it plays a pathological role in osteoarthritic progression.

Regional Distribution of Extracellular Volume Quantified by Cardiac CT in Aortic Stenosis: Insights Into Disease Mechanisms and Impact on Outcomes

BACKGROUND

Extracellular volume fraction (ECV) is a marker for myocardial fibrosis and infiltration, can be quantified using cardiac computed tomography (ECVCT), and has prognostic utility in several diseases. This study aims to map out regional differences in ECVCT to obtain greater insights into the pathophysiological mechanisms of ECV expansion and its clinical implications.

METHODS

Three prospective cohorts were included: patients with aortic stenosis (AS) and coexisting AS and transthyretin cardiac amyloidosis were referred for a transcatheter aortic valve replacement and had ECG-gated CT angiography and Technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid scintigraphy to differentiate between the 2 cohorts. Controls had CT angiography and cardiac magnetic resonance demonstrating no significant coronary artery disease or infarction. Global and regional ECVCT was analyzed, and its association with mortality was assessed for patients with AS.

RESULTS

In 199 patients, controls (n=65; 66% male), AS (n=115), and coexisting AS and transthyretin cardiac amyloidosis (n=19) had a global ECVCT of 26.1 (25.0-27.8%) versus 29.1 (27.5-31.1%) versus 37.4 (32.5-46.6%), respectively; P<0.001. Across cohorts, ECVCT was higher at the base (versus apex), the inferoseptum (versus anterolateral wall), and the subendocardium (versus subepicardium); P<0.05 for all. Among patients with AS, epicardial ECVCT, rather than any other regional value or global ECVCT, was the strongest predictor of mortality at a median of 3.9 (max 6.3) years (adjusted hazard ratio, 1.21 [95% CI, 1.08-1.36]; P=0.002).

CONCLUSIONS

Regional differences in ECVCT suggest a predilection for fibrosis and amyloid infiltration at the base, subendocardium, inferior wall, and septum more than the anterior and lateral myocardium. ECVCT can predict long-term mortality with the subepicardium demonstrating the strongest discriminatory power.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT03029026 and NCT03094143.

Transcatheter Aortic Valve Replacement With the Navitor System: Real-World United Kingdom Experience

The Navitor transcatheter heart valve (THV) is the latest iteration of the Portico self-expanding valve system. Early prospective studies have shown promising outcomes, however, there is a lack of complementary 'real-world' data. This study aimed to assess early safety and efficacy outcomes of the Navitor THV using registry data from 6 high-volume United Kingdom transcatheter aortic valve replacement (TAVR) centers. Demographic, procedural, and in-hospital outcome data were retrieved from 6 United Kingdom centers. The primary safety end point was 30-day mortality. Primary efficacy end points were procedural success, mean aortic gradient, and ≥moderate paravalvular leak. Secondary end points included rates of new permanent pacemaker implantation, stroke, and vascular injury. A total of 574 patients (mean age 83.4 years; 54.5% female) underwent Navitor TAVR between January 2020 and May 2023. The 30-day mortality in this patient cohort was 1.6%. Procedural success was 98.1%, mean echo-derived gradient post-TAVR was 7.7 ± 4.8 mm Hg (95% confidence interval [CI] 7.2 to 8.3, p <0.001) and 5.1% of patients had ≥moderate paravalvular leak (sample proportion estimate [p̂] = 0.051, 95% CI [0.035, 0.073], p <0.001). New permanent pacemaker implantation to discharge was required in 11% (p̂ = 0.119, 95% CI 0.088 to 0.158, p <0.001), stroke occurred in 1.2% of patients (p̂ = 0.017, 95% CI 0.006 to 0.036, p <0.001) and significant vascular injury in 1.6% (p̂ = 0.014, 95% CI 0.005 to 0.032, p <0.001). In conclusion, early procedural outcomes with Navitor TAVR compare favorably to new-generation THVs. Procedural success was high with a low incidence of complications.

A novel device for atrial septal defect occlusion (GORE CARDIOFORM)

The GORE CARDIOFORM atrial septal defect (ASD) Occluder (GCA) is composed of a platinum-filled nitinol wire frame covered with expanded polytetrafluoroethylene, making it softer and more conformable compared with nitinol mesh devices. After the ASSURED clinical study confirmed the efficacy and safety of the device, it received U.S. Food and Drug Administration approval and a European conformity mark. Our aim was to understand the learning curve implicated in using the GCA for ASD closure in paediatric and adult patients as well as to study the early outcomes. To this end, a review of ASD device closures with GCA in 4 UK centres was conducted between January 2020 and January 2023. Implantation success was the primary outcome; the secondary outcomes were serious adverse events, including new onset arrhythmia. In all, 135 patients were included, and 128 (95%) had successful ASD device closure with GCA. The median patient age was 49 years, the median defect size was 18 mm, and the median device size was 37 mm. The median follow-up time was 6 months (interquartile range 1-14). One device embolisation occurred, and 15 patients (12% of GCA implantations) developed new onset arrhythmia - this was not related to patient age, defect diameter or device oversizing but was positively associated with device size. With growing experience using GCA, the device can be applied to a wide variety of ASD sizes and morphologies. Given the number of successful implantations with an absence of aortic erosion, as well as the ability to perforate through the device should procedures be required in the left atrium, the GCA device is an important addition for interventionists who close atrial septal defects.

A Paradigm Shift from International to Transnational Medical Education

In recent years, the number of medical students seeking international opportunities has grown. To satisfy these demands, collaborative international programs have been developed. However, the benefits of these programs are limited as they employ an international medical education (IME) approach where only the students are exchanged. In this commentary, we discuss the current models of IME and propose a paradigm shift to a transnational approach wherein the student, faculty, and curriculum are exchanged allowing for increased integration and awareness of cultural and educational approaches to treatment that can be retained and incorporated into future practice to advance healthcare across the globe.

Brief Report: Hepatitis B Infection or Reactivation After Switch to 2-Drug Antiretroviral Therapy: A Case Series, Literature Review, and Management Discussion

BACKGROUND

Two-drug antiretroviral therapy (ART) without hepatitis B virus (HBV) activity is prescribed for persons with HIV as simplified or salvage therapy. Although two-drug regimens are not recommended for persons with chronic HBV infection, guidelines do not address their use in those with HBV susceptibility and/or core antibody reactivity. We present a case series of individuals with HBV infection or reactivation following switch to two-drug, non-HBV-active ART.

SETTING

HIV primary care clinics of an academic medical center in New York, NY.

METHODS

Case surveillance was conducted to identify persons with HBV surface antigenemia and viremia following two-drug ART switch. Clinical characteristics and outcomes were ascertained through chart review.

RESULTS

Four individuals with HBV infection or reactivation after ART switch were identified. Two had HBV susceptibility, 1 had core antibody reactivity, and 1 had surface antigen reactivity preswitch. All eligible persons had received HBV vaccination: 2 with low-level antibody response and 1 with persistent nonresponse. Two presented with fulminant hepatitis, with 1 required liver transplantation.

CONCLUSION

Two-drug ART switch may pose risk of HBV infection or reactivation. We propose careful patient selection and monitoring through the following: (1) assessment of HBV serologies before switch and periodically thereafter, (2) vaccination and confirmation of immunity before switch, (3) risk stratification and counseling about HBV reactivation for those with core antibody, (4) preemptive HBV DNA monitoring for those at the risk of reactivation, (5) continuation of HBV-active prophylaxis when above measures are not feasible, and (6) continuation of HBV-active therapy and surveillance for chronic HBV infection.

Fisetin Attenuates Cellular Senescence Accumulation During Culture Expansion of Human Adipose-Derived Stem Cells

Mesenchymal stem cells (MSCs) have long been viewed as a promising therapeutic for musculoskeletal repair. However, regulatory concerns including tumorgenicity, inconsistencies in preparation techniques, donor-to-donor variability, and the accumulation of senescence during culture expansion have hindered the clinical application of MSCs. Senescence is a driving mechanism for MSC dysfunction with advancing age. Often characterized by increased reactive oxygen species, senescence-associated heterochromatin foci, inflammatory cytokine secretion, and reduced proliferative capacity, senescence directly inhibits MSCs efficacy as a therapeutic for musculoskeletal regeneration. Furthermore, autologous delivery of senescent MSCs can further induce disease and aging progression through the secretion of the senescence-associated secretory phenotype (SASP) and mitigate the regenerative potential of MSCs. To alleviate these issues, the use of senolytic agents to selectively clear senescent cell populations has become popular. However, their benefits to attenuating senescence accumulation in human MSCs during the culture expansion process have not yet been elucidated. To address this, we analyzed markers of senescence during the expansion of human primary adipose-derived stem cells (ADSCs), a population of fat-resident MSCs commonly used in regenerative medicine applications. Next, we used the senolytic agent fisetin to determine if we can reduce these markers of senescence within our culture-expanded ADSC populations. Our results indicate that ADSCs acquire common markers of cellular senescence including increased reactive oxygen species, senescence-associated β-galactosidase, and senescence-associated heterochromatin foci. Furthermore, we found that the senolytic agent fisetin works in a dose-dependent manner and selectively attenuates these markers of senescence while maintaining the differentiation potential of the expanded ADSCs.

Correcting image distortions from a nonlinear B 1 + $$ {\boldsymbol{B}}_{\mathbf{1}}^{+} $$ -gradient field in frequency-modulated Rabi-encoded echoes

PURPOSE

To correct image distortions that result from nonlinear spatial variation in the transmit RF field amplitude (B 1 + $$ {B}_1^{+} $$ ) when performing spatial encoding with the method called frequency-modulated Rabi encoded echoes (FREE).

THEORY AND METHODS

An algorithm developed to correct image distortion resulting from the use of nonlinear static field (B0 ) gradients in standard MRI is adapted herein to correct image distortion arising from a nonlinearB 1 + $$ {B}_1^{+} $$ -gradient field in FREE. From aB 1 + $$ {B}_1^{+} $$ -map, the algorithm performs linear interpolation and intensity scaling to correct the image. The quality of the distortion correction is evaluated in 1.5T images of a grid phantom and human occipital lobe.

RESULTS

An expanded theoretical description of FREE revealed the symmetry between thisB 1 + $$ {B}_1^{+} $$ -gradient field spatial-encoding and standard B0 -gradient field spatial-encoding. The adapted distortion-correction algorithm substantially reduced image distortions arising in the spatial dimension that was encoded by the nonlinearB 1 + $$ {B}_1^{+} $$ gradient of a circular surface coil.

CONCLUSION

Image processing based on straightforward linear interpolation and intensity scaling, as previously applied in conventional MRI, can effectively reduce distortions in FREE images acquired with nonlinearB 1 + $$ {B}_1^{+} $$ -gradient fields.

MRL/MpJ Mice Resist to Age-Related and Long-Term Ovariectomy-Induced Bone Loss: Implications for Bone Regeneration and Repair

Osteoporosis and age-related bone loss increase bone fracture risk and impair bone healing. The need for identifying new factors to prevent or treat bone loss is critical. Previously, we reported that young MRL/MpJ mice have superior bone microarchitecture and biomechanical properties as compared to wild-type (WT) mice. In this study, MRL/MpJ mice were tested for resistance to age-related and long-term ovariectomy-induced bone loss to uncover potential beneficial factors for bone regeneration and repair. Bone tissues collected from 14-month-old MRL/MpJ and C57BL/6J (WT) mice were analyzed using micro-CT, histology, and immunohistochemistry, and serum protein markers were characterized using ELISAs or multiplex assays. Furthermore, 4-month-old MRL/MpJ and WT mice were subjected to ovariectomy (OV) or sham surgery and bone loss was monitored continuously using micro-CT at 1, 2, 4, and 6 months (M) after surgery with histology and immunohistochemistry performed at 6 M post-surgery. Sera were collected for biomarker detection using ELISA and multiplex assays at 6 M after surgery. Our results indicated that MRL/MpJ mice maintained better bone microarchitecture and higher bone mass than WT mice during aging and long-term ovariectomy. This resistance of bone loss observed in MRL/MpJ mice correlated with the maintenance of higher OSX⁺ osteoprogenitor cell pools, higher activation of the pSMAD5 signaling pathway, more PCNA⁺ cells, and a lower number of osteoclasts. Systemically, lower serum RANKL and DKK1 with higher serum IGF1 and OPG in MRL/MpJ mice relative to WT mice may also contribute to the maintenance of higher bone microarchitecture during aging and less severe bone loss after long-term ovariectomy. These findings may be used to develop therapeutic approaches to maintain bone mass and improve bone regeneration and repair due to injury, disease, and aging.

Percutaneous heart valves demonstrating long-term durability: A case series of Melody valves in the pulmonary position lasting up to 19 years

It is uncertain how long catheter delivered percutaneous heart valves may last. In congenital cardiology, stenosis and regurgitation of right ventricular to pulmonary artery conduits and valves is common, leading to repeated operations for young patients with concomitant mortality and morbidity. It has also been unclear whether percutaneous pulmonary valves last as long as surgical pulmonary valves. When the current generation of the percutaneous pulmonary valve was first implanted in the United Kingdom from 2003, randomized trials were initially not performed, decided on a case-by-case basis in congenital cardiology, nor long-term registries kept. We describe three cases where such percutaneous heart valves have lasted up to 19 years. All valves were working without significant stenosis and minor degrees of regurgitation on long-term echocardiographic follow-up, patients being asymptomatic. This demonstrates that percutaneous pulmonary valves can achieve long-term durability and may prevent the need for otherwise high-risk surgery in congenital cardiac patients.

Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

Mechanical strain drives exosome production, function, and miRNA cargo in C2C12 muscle progenitor cells

Mesenchymal stem cells (MSCs) have been proven to promote tissue repair. However, concerns related to their clinical application and regulatory hurdles remain. Recent data has demonstrated the proregenerative secretome of MSCs can result in similar effects in the absence of the cells themselves. Within the secretome, exosomes have emerged as a promising regenerative component. Exosomes, which are nanosized lipid vesicles secreted by cells, encapsulate micro-RNA (miRNA), RNA, and proteins that drive MSCs regenerative potential with cell specific content. As such, there is an opportunity to optimize the regenerative potential of MSCs, and thus their secreted exosome fraction, to improve clinical efficacy. Exercise is one factor that has been shown to improve muscle progenitor cell function and regenerative potential. However, the effect of exercise on MSC exosome content and function is still unclear. To address this, we used an in vitro culture system to evaluate the effects of mechanical strain, an exercise mimetic, on C2C12 (muscle progenitor cell) exosome production and proregenerative function. Our results indicate that the total exosome production is increased by mechanical strain and can be regulated with different tensile loading regimens. Furthermore, we found that exosomes from mechanically stimulated cells increase proliferation and myogenic differentiation of naïve C2C12 cells. Lastly, we show that exosomal miRNA cargo is differentially expressed following strain. Gene ontology mapping suggests positive regulation of bone morphogenetic protein signaling, regulation of actin-filament-based processes, and muscle cell apoptosis may be at least partially responsible for the proregenerative effects of exosomes from mechanically stimulated C2C12 muscle progenitor cells.

Mitral regurgitation management: a systematic review of clinical practice guidelines and recommendations

Multiple guidelines exist for the diagnosis and management of mitral regurgitation (MR), the second most common valvular heart disease in high-income countries, with recommendations that do not always match. We systematically reviewed guidelines on diagnosis and management of MR, highlighting similarities and differences to guide clinical decision-making. We searched national and international guidelines in MEDLINE and EMBASE (1 June 2010 to 1 September 2021), the Guidelines International Network, National Guideline Clearinghouse, National Library for Health Guidelines Finder, Canadian Medical Association Clinical Practice Guidelines Infobase, and websites of relevant organizations. Two reviewers independently screened the abstracts and identified articles of interest. Guidelines that were rigorously developed (as assessed with the Appraisal of Guidelines for Research and Evaluation II instrument) were retained for analysis. Five guidelines were retained. There was consensus on a multidisciplinary approach from the heart team and for the definition and grading of severe primary MR. There was general agreement on the thresholds for intervention in symptomatic and asymptomatic primary MR; however, discrepancies were present. There was agreement on optimization of medical therapy in severe secondary MR and intervention in patients symptomatic despite optimal medical therapy, but no consensus on the choice of intervention (surgical repair/replacement vs. transcatheter approach). Cut-offs for high-risk intervention in MR, risk stratification of progressive MR, and guidance on mixed valvular disease were sparse.

The use of heparin/polycation coacervate sustain release system to compare the bone regenerative potentials of 5 BMPs using a critical sized calvarial bone defect model

Nonunion following bone fracture and segmental bone defects are challenging clinical conditions. To combat this clinical dilemma, development of new bone tissue engineering therapies using biocompatible materials to deliver bone growth factors is desirable. This aim of this study is to use a heparin/polycation coacervate sustained-release platform to compare 5 bone morphogenetic proteins (BMPs) for promoting bone defect healing in a critical sized calvarial defect model. The in vitro 3D osteogenic pellet cultures assays demonstrated that BMPs 2, 4, 6, 7 and 9 all enhanced mineralization in vitro compared to the control group. BMP2 resulted in higher mineralized volume than BMP4 and BMP6. All BMPs and the control group activated the pSMAD5 signaling pathway and expressed osterix (OSX). The binding of BMP2 with coacervate significantly increased the coacervate average particle size. BMP2, 4, 6, & 7 bound to coacervate significantly increased the Zeta potential of the coacervate while BMP9 binding showed insignificant increase. Furthermore, using a monolayer culture osteogenic assay, it was found that hMDSCs cultured in the coacervate BMP2 osteogenic medium expressed higher levels of RUNX2, OSX, ALP and COX-2 compared to the control and BMPs 4, 6, 7 & 9. Additionally, the coacervate complex can be loaded with up to 2 μg of BMP proteins for sustained release. In vivo, when BMPs were delivered using the coacervate sustained release system, BMP2 was identified to be the most potent BMP promoting bone regeneration and regenerated 10 times of new bone than BMPs 4, 6 & 9. BMP7 also stimulated robust bone regeneration when compared to BMPs 4, 6 & 9. The quality of the newly regenerated bone by all BMPs delivered by coacervate is equivalent to the host bone consisting of bone matrix and bone marrow with normal bone architecture. Although the defect was not completely healed at 6 weeks, coacervate sustain release BMPs, particularly BMP2 and BMP7, could represent a new strategy for treatment of bone defects and non-unions.

Predictors of post-TAVI conduction abnormalities in patients with bicuspid aortic valves

OBJECTIVES

This study evaluates predictors of conduction abnormalities (CA) following transcatheter aortic valve implantation (TAVI) in patients with bicuspid aortic valves (BAV).

BACKGROUND

TAVI is associated with CA that commonly necessitate a permanent pacemaker. Predictors of CA are well established among patients with tricuspid aortic valves but not in those with BAV.

METHODS

This is a single-centre, retrospective, observational study of patients with BAV treated with TAVI. Pre-TAVI ECG and CT scans and procedural characteristics were evaluated in 58 patients with BAV. CA were defined as a composite of high-degree atrioventricular block, new left bundle branch block with a QRS >150 ms or PR >240 ms and right bundle branch block with new PR prolongation or change in axis. Predictors of CA were identified using regression analysis and optimum cut-off values determined using area under the receiver operating characteristic curve analysis.

RESULTS

CA occurred in 35% of patients. Bioprosthesis implantation depth, the difference between membranous septum (MS) length and implantation depth (δMSID) and device landing zone (DLZ) calcification adjacent to the MS were identified as univariate predictors of CA. The optimum cut-off for δMSID was 1.25 mm. Using this cut-off, low δMSID and DLZ calcification adjacent to MS predicted CA, adjusted OR 8.79, 95% CI 1.88 to 41.00; p=0.01. Eccentricity of the aortic valve annulus, type of BAV and valve calcium quantity and distribution did not predict CA.

CONCLUSIONS

In BAV patients undergoing TAVI, short δMSID and DLZ calcification adjacent to MS are associated with an increased risk of CA.

Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Delays in the Identification and Assessment of in-Hospital Stroke Patients

OBJECTIVES

In-hospital stroke is associated with poor outcomes. Reasons for delays, use of interventions, and presence of large vessel occlusion are not well characterized.

MATERIALS AND METHODS

A retrospective single center cohort of 97 patients with in-hospital stroke was analyzed to identify factors associated with delays from last known normal to symptom identification and to stroke team alerting. Stroke interventions and presence of large vessel occlusion were also assessed.

RESULTS

Strokes were predominantly on surgery services (70%), ischemic (82%), and severe (median NIHSS 16; interquartile range [IQR] 6-24). There were long delays from last known normal to symptom identification (median 5.1 hours, IQR 1.0-19.7 hours), symptom identification to stroke team alerting (median 2.1 hours, IQR 0.5-9.9 hours), and total time from last known normal to alerting (median 11.4 [IQR 2.7-34.2] hours). In univariable analysis, being on a surgical service, in an ICU, intubated, and higher NIHSS were associated with delays. In multivariable analysis only intubation was independently associated with time from last known normal to symptom identification (coefficient 20 hours, IQR 0.2 - 39.8, p=0.047). Interventions were given to 17/80 (21%) ischemic stroke patients; 3 (4%) received IV tPA and 14 (18%) underwent thrombectomy. Vascular imaging occurred in 57/80 (71%) ischemic stroke patients and 21/57 (37%) had large vessel occlusion.

CONCLUSIONS

Hospitalized patients with stroke experience long delays from symptom identification to stroke team alerting. Intubation was strongly associated with delay to symptom identification. Although stroke severity was high and large vessel occlusion common, many patients did not receive acute interventions.

B1 -gradient-based MRI using frequency-modulated Rabi-encoded echoes

PURPOSE

Reduce expense and increase accessibility of MRI by eliminating pulsed field (B0 ) gradient hardware.

METHODS

A radiofrequency imaging method is described that enables spatial encoding without B0 gradients. This method, herein referred to as frequency-modulated Rabi-encoded echoes (FREE), utilizes adiabatic full passage pulses and a gradient in the RF field (B1 ) to produce spatially dependent phase modulation, equivalent to conventional phase encoding. In this work, Cartesian phase encoding was accomplished using FREE in a multi-shot double spin-echo sequence. Theoretical analysis and computer simulations investigated the influence of resonance offset and B1 -gradient steepness and magnitude on reconstruction quality, which limit other radiofrequency imaging methodologies. Experimentally, FREE was compared to conventional phase-encoded MRI on human visual cortex using a simple surface transceiver coil.

RESULTS

Image distortions occurred in FREE when using nonlinear B1 fields where the phase dependence becomes nonlinear, but with minimal change in signal intensity. Resonance offset effects were minimal for Larmor frequencies within the adiabatic full-passage pulse bandwidth.

CONCLUSION

For the first time, FREE enabled slice-selective 2D imaging of the human brain without a B0 gradient in the y-direction. FREE achieved high resolution in regions where the B1 gradient was steepest, whereas images were distorted in regions where nonlinearity in the B1 gradient was significant. Given that FREE experiences no significant signal loss due to B1 nonlinearities and resonance offset, image distortions shown in this work might be corrected in the future based on B1 and B0 maps.

Impact of afterload and infiltration on coexisting aortic stenosis and transthyretin amyloidosis

OBJECTIVE

The coexistence of wild-type transthyretin cardiac amyloidosis (ATTR) is common in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). However, the impact of ATTR and AS on the resultant AS-ATTR is unclear and poses diagnostic and management challenges. We therefore used a multicohort approach to evaluate myocardial structure, function, stress and damage by assessing age-related, afterload-related and amyloid-related remodelling on the resultant AS-ATTR phenotype.

METHODS

We compared four samples (n=583): 359 patients with AS, 107 with ATTR (97% Perugini grade 2), 36 with AS-ATTR (92% Perugini grade 2) and 81 age-matched and ethnicity-matched controls. 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy was used to diagnose amyloidosis (Perugini grade 1 was excluded). The primary end-point was NT-pro Brain Natriuretic Peptide (BNP) and secondary end-points related to myocardial structure, function and damage.

RESULTS

Compared with older age controls, the three disease cohorts had greater cardiac remodelling, worse function and elevated NT-proBNP/high-sensitivity Troponin-T (hsTnT). NT-proBNP was higher in AS-ATTR (2844 (1745, 4635) ng/dL) compared with AS (1294 (1077, 1554)ng/dL; p=0.002) and not significantly different to ATTR (3272 (2552, 4197) ng/dL; p=0.63). Diastology, hsTnT and prevalence of carpal tunnel syndrome were statistically similar between AS-ATTR and ATTR and higher than AS. The left ventricular mass indexed in AS-ATTR was lower than ATTR (139 (112, 167) vs 180 (167, 194) g; p=0.013) and non-significantly different to AS (120 (109, 130) g; p=0.179).

CONCLUSIONS

The AS-ATTR phenotype likely reflects an early stage of amyloid infiltration, but the combined insult resembles ATTR. Even after treatment of AS, ATTR-specific therapy is therefore likely to be beneficial.

61 AUDIT: MEDICATION REVIEW POST INPATIENT FALLS

Background

Falls are the most commonly reported incident in the Health Service Executive (HSE). Inappropriate medications and polypharmacy in the elderly can contribute to increased falls risk.

Our aim was to assess whether a medication review was being completed at the time of the post-fall clinician review.

Methods

We completed a retrospective chart review using an audit tool of consecutive inpatient falls, resulting in serious injury, from March–December 2019.

Standards measured against were: HSE Guideline—Service User Falls: A Practical Guide for Review, Medicines and Falls in Hospital: British Society Guidelines, STOPP & START criteria and NICE Guidelines: Falls in Older People 2013.

Results

We identified 33 charts for review (n = 33)—54.55% (18) female and 45.45% (15) male. Average age was 81 ± 11.2 years. The immediate post-fall review was mainly completed by interns (48.49% (16)) and SHO’s (39.39% (13)). A medication review was carried out 9.09% (3) of the time.

A total of n = 28 (84.85%) had poly pharmacy. When analysed for medications known to increase risk of falling, 51.52% (n = 17) were on anti-hypertensives, 45.45% (n = 15) on laxatives, 24.24% (n = 8) on sedative medications, 18.18% (n = 6) on hypnotics/anxiolytics, 15.15% (n = 5) on opioids and 15.15% (n = 5) on diuretics at the time of fall. The majority of these medications (77.42% (n = 24)) were commenced prior to admission. None of these medications were discontinued or the dose changed on review post fall.

Conclusion

Our audit demonstrates that in a cohort of patients who had an inpatient fall medication discontinuation and dose reductions were not performed. Yet, a high burden of polypharmacy and high-risk falls medication were found. This may result in missing a pertinent opportunity to prevent future falls. We advise a structured medication review is carried out for each patient who suffers an in-patient fall to efficiently modify such an easily identifiable risk factor.

Reducing the Complexity of Model-Based MRI Reconstructions via Sparsification

Model-based reconstruction methods have emerged as a powerful alternative to classical Fourier-based MRI techniques, largely because of their ability to explicitly model (and therefore, potentially overcome) moderate field inhomogeneities, streamline reconstruction from non-Cartesian sampling, and even allow for the use of custom designed non-Fourier encoding methods. Their application in such scenarios, however, often comes with a substantial increase in computational cost, owing to the fact that the corresponding forward model in such settings no longer possesses a direct Fourier Transform based implementation. This paper introduces an algorithmic framework designed to reduce the computational burden associated with model-based MRI reconstruction tasks. The key innovation is the strategic sparsification of the corresponding forward operators for these models, giving rise to approximations of the forward models (and their adjoints) that admit low computational complexity application. This enables overall a reduced computational complexity application of popular iterative first-order reconstruction methods for these reconstruction tasks. Computational results obtained on both synthetic and experimental data illustrate the viability and efficiency of the approach.

Reintroduction of elective cardiac interventions in the era of COVID-19: the Barts experience

Background

The response to COVID-19 has required cancellation of all but the most urgent procedures; there is therefore a need for the reintroduction of a safe elective pathway.

Methods

This was a study of a pilot pathway performed at Barts Heart Centre for the admission of patients requiring elective coronary and structural procedures during the COVID-19 pandemic (April–June 2020). All patients on coronary and structural waiting lists were screened for procedural indications, urgency and adverse features for COVID-19 prognosis and discussed at dedicated multidisciplinary teams. Dedicated admission pathways involving preadmission isolation, additional consent, COVID-19 PCR testing and dedicated clean areas were used.

Results

143 patients (101 coronary and 42 structural) underwent procedures (coronary angiography, percutaneous coronary intervention, transcatheter aortic valve intervention and MitralClip) during the study period. The average age was 68.2; 74% were male; and over 93% had one or more moderate COVID-19 risk factors. All patients were COVID-19 PCR negative on admission with (8.1%) COVID-19 antibody positive (swab negative). All procedures were performed successfully with low rates of procedural complications (9.8%). At 2-week follow-up, no patients had symptoms or confirmed COVID-19 infection with significant improvements in quality if life and symptoms.

Conclusion

We demonstrated that patients undergoing coronary and structural procedures can be safely admitted during the COVID-19 pandemic, with no patients contracting COVID-19 during their admission. Reassuringly, patients reflective of typical practice, that is, those at moderate or higher risk, were treated successfully. This pilot provides important information applicable to other settings, specialties and areas to reintroduce services safely.

Dual polarity encoded MRI using high bandwidth radiofrequency pulses for robust imaging with large field inhomogeneity

PURPOSE

The ability to use dual polarity encoded MRI with the missing pulse steady-state free precession (MP-SSFP) sequence is demonstrated to perform robust MRI with low radiofrequency (RF) amplitude, where the field is distorted by embedding metallic screws in an agar phantom. Image-based estimation of the 3D ΔB₀ map and image distortion correction is shown to require ~1 minute to perform.

THEORY AND METHODS

Dual polarity encoded MP-SSFP was implemented at 1.5T and used to image agar phantoms with one stainless steel and one titanium screw embedded inside. A multispectral fast spin-echo acquisition was performed for comparison. Self-consistent ΔB₀ estimation is performed iteratively using a 3D B-spline basis, which is compared to the ΔB₀ estimate generated by the multispectral sequence.

RESULTS

Dual polarity encoded MP-SSFP yields image quality similar to the multispectral sequence used with substantially less imaging time, provided the MP-SSFP experimental parameters are chosen well. The multispectral sequence appears to visualize modestly closer in proximity to the metallic screws used, despite the spectral bins covering the same bandwidth as the pulses used in MP-SSFP. However, MP-SSFP avoids ripple artifacts characteristic of the multispectral sequence. The ΔB₀ estimate generated by MP-SSFP is qualitatively similar to that generated by the multispectral sequence but larger in magnitude.

CONCLUSION

Despite longer processing time compared to multispectral imaging, MP-SSFP yields similar image quality with significantly lower acquisition times in the absence of parallel imaging. The work herein demonstrates the ability to perform 3D ΔB₀ estimation and image correction within a reasonable amount of time, ~1 minute.

Myocardial fibrosis quantification by cardiac CT predicts outcome in severe aortic stenosis

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Background

Myocardial extracellular volume (ECV) increases with fibrosis, oedema or infiltration. ECV by CMR predicts all-cause and cardiovascular mortality in severe AS after valve intervention. Previous studies have shown that ECV can be reliably quantified by computed tomography (ECVCT), but these studies have not differentiated between ECV elevation due to fibrosis or cardiac amyloid deposition (13-16% of patients with severe AS). 

Purpose

We hypothesised that ECVCT quantification, performed as part of a transcatheter aortic valve implantation (TAVI) work-up CT, predicts survival in patients with severe AS without cardiac amyloid (lone AS).

Methods

Patients aged ≥75, with severe AS, referred for TAVI at Barts Heart Centre (as part of ATTRact-AS (NCT03029026)) underwent CT as part of their clinical work-up. All patients had 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy and those with a positive result were excluded.  CT was performed on a 128-slice dual-source 3rdgeneration scanner (Siemens Somatom FORCE) and ECVCT was acquired during the TAVI work-up CT using additional pre- and 3-minute post-contrast ‘axial shuttle mode’ acquisitions (no additional contrast).  ECVCT was calculated from the Hounsfield units (HU) and a venous haematocrit (HCT): ECVCT = (1-HCT) x (ΔHUmyo/ΔHUblood).

Results

Following exclusion of 16 patients with cardiac uptake on DPD, 93 patients (41% male, aged 85 ± 5 years) were included in the study.  All patients had severe AS (AV Vmax 4.12 ± 0.63m/s, mean AV gradient 42 ± 14mmHg, AVA 0.71 ± 0.23cm2). The mean HCT was 0.38 ± 0.04 and total dose-length product for additional research scans was 364 ± 41 mGy.cm. 76 patients (82%) underwent TAVI. ECVCT was 32 ± 3% in the entire cohort, which we then split into those with a ‘higher’ ECVCT (&gt;34%, n = 23, representing the highest quartile) and those with a ‘lower’ ECVCT (≤34%, n = 70, representing the lower quartiles). Over a median follow-up of 25 months (IQR 17-34 months) there were 27 deaths (29%), of whom 11 did not undergo TAVI (41%). There were 10 deaths in the 23 patients (44%) with a higher ECVCT, compared to 17 in the 70 patients (24%) with a lower ECVCT (p = 0.03, figure 1). This mortality difference remained significant when those patients who did not undergo TAVI were excluded (p = 0.03).

Conclusions

Myocardial fibrosis quantified by ECVCT is associated with a significantly worse prognosis in lone AS, even after patients with AS-amyloid are excluded. ECVCT can be performed as a simple addition to the TAVI work-up CT and provides additional prognostic information.

Abstract Figure.

Vancomycin Wrap for Anterior Cruciate Ligament Surgery: Molecular Insights

BACKGROUND

The use of the vancomycin wrap to pretreat the hamstring graft in anterior cruciate ligament reconstruction (ACLR) has grown in popularity since it was first described in 2012 and has significantly reduced rates of postoperative infection. However, it remains unknown if this antibiotic treatment affects the molecular composition of the graft.

PURPOSE

To establish whether treatment with vancomycin at 5 mg/mL, the most commonly used concentration, alters the molecular function of the hamstring graft in ACLR.

STUDY DESIGN

Controlled laboratory study.

METHODS

Surplus hamstring tendon collected after routine ACLR surgery was used for in vitro cell culture and ex vivo tissue experiments. Vancomycin was used at 5 mg/mL in RPMI or saline diluent to treat cells and tendon tissue, respectively, with diluent control conditions. Cell viability at 30, 60, and 120 minutes was assessed via colorimetric viability assay. Tendon cells treated with control and experimental conditions for 1 hour was evaluated using semiquantitative reverse transcription analysis, immunohistochemistry staining, and protein quantitation via enzyme-linked immunosorbent assay for changes in apoptotic, matrix, and inflammatory gene and protein expression.

RESULTS

Vancomycin treatment at 5 mg/mL significantly reduced tenocyte viability in vitro after 60 minutes of treatment (P < .05); however, this was not sustained at 120 minutes. Vancomycin-treated tendon tissue showed no significant increase in apoptotic gene expression, or apoptotic protein levels in tissue or supernatant, ex vivo. Vancomycin was associated with a reduction in inflammatory proteins from treated tendon supernatants (IL-6; P < .05).

CONCLUSION

Vancomycin did not significantly alter the molecular structure of the hamstring graft. Reductions in matrix protein and inflammatory cytokine release point to a potential beneficial effect of vancomycin in generating a homeostatic environment.

CLINICAL RELEVANCE

Vancomycin ACL wrap does not alter the molecular structure of the ACL hamstring graft and may improve graft integrity.

Survival relative to pacemaker status after transcatheter aortic valve implantation

OBJECTIVES

To determine whether a permanent pacemaker (PPM) in situ can enhance survival after transcatheter aortic valve implantation (TAVI), in a predominantly inoperable or high risk cohort.

BACKGROUND

New conduction disturbances are the most frequent complication of TAVI, often necessitating PPM implantation before hospital discharge.

METHODS

We performed an observational cohort analysis of the UK TAVI registry (2007-2015). Primary and secondary endpoints were 30-day post-discharge all-cause mortality and long-term survival, respectively.

RESULTS

Of 8,651 procedures, 6,815 complete datasets were analyzed. A PPM at hospital discharge, irrespective of when implantation occurred (PPM 1.68% [22/1309] vs. no PPM 1.47% [81/5506], odds ratio [OR] 1.14, 95% confidence interval [CI] 0.71-1.84; p = .58), or a PPM implanted peri- or post-TAVI only (PPM 1.44% [11/763] vs. no PPM 1.47% [81/5506], OR 0.98 [0.51-1.85]; p = .95) did not significantly reduce the primary endpoint. Patients with a PPM at discharge were older, male, had right bundle branch block at baseline, were more likely to have received a first-generation self-expandable prosthesis and had experienced more peri- and post-procedural complications including bailout valve-in-valve rescue, bleeding and acute kidney injury. A Cox proportional hazards model demonstrated significantly reduced long-term survival in all those with a PPM, irrespective of implantation timing (hazard ratio [HR] 1.14 [1.02-1.26]; p = .019) and those receiving a PPM only at the time of TAVI (HR 1.15 [1.02-1.31]; p = .032). The reasons underlying this observation warrant further investigation.

CONCLUSIONS

A PPM did not confer a survival advantage in the first 30 days after hospital discharge following TAVI.

Prevalence and Outcomes of Concomitant Aortic Stenosis and Cardiac Amyloidosis

BACKGROUND

Older patients with severe aortic stenosis (AS) are increasingly identified as having cardiac amyloidosis (CA). It is unknown whether concomitant AS-CA has worse outcomes or results in futility of transcatheter aortic valve replacement (TAVR).

OBJECTIVES

This study identified clinical characteristics and outcomes of AS-CA compared with lone AS.

METHODS

Patients who were referred for TAVR at 3 international sites underwent blinded research core laboratory 99mtechnetium-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) bone scintigraphy (Perugini grade 0: negative; grades 1 to 3: increasingly positive) before intervention. Transthyretin-CA (ATTR) was diagnosed by DPD and absence of a clonal immunoglobulin, and light-chain CA (AL) was diagnosed via tissue biopsy. National registries captured all-cause mortality.

RESULTS

A total of 407 patients (age 83.4 ± 6.5 years; 49.8% men) were recruited. DPD was positive in 48 patients (11.8%; grade 1: 3.9% [n = 16]; grade 2/3: 7.9% [n = 32]). AL was diagnosed in 1 patient with grade 1. Patients with grade 2/3 had worse functional capacity, biomarkers (N-terminal pro-brain natriuretic peptide and/or high-sensitivity troponin T), and biventricular remodeling. A clinical score (RAISE) that used left ventricular remodeling (hypertrophy/diastolic dysfunction), age, injury (high-sensitivity troponin T), systemic involvement, and electrical abnormalities (right bundle branch block/low voltages) was developed to predict the presence of AS-CA (area under the curve: 0.86; 95% confidence interval: 0.78 to 0.94; p < 0.001). Decisions by the heart team (DPD-blinded) resulted in TAVR (333 [81.6%]), surgical AVR (10 [2.5%]), or medical management (65 [15.9%]). After a median of 1.7 years, 23% of patients died. One-year mortality was worse in all patients with AS-CA (grade: 1 to 3) than those with lone AS (24.5% vs. 13.9%; p = 0.05). TAVR improved survival versus medical management; AS-CA survival post-TAVR did not differ from lone AS (p = 0.36).

CONCLUSIONS

Concomitant pathology of AS-CA is common in older patients with AS and can be predicted clinically. AS-CA has worse clinical presentation and a trend toward worse prognosis, unless treated. Therefore, TAVR should not be withheld in AS-CA.

Otolaryngology Resident Wellness, Training, and Education in the Early Phase of the COVID-19 Pandemic

OBJECTIVE

To determine changes in the residency experience early in the COVID-19 pandemic and evaluate wellness measures among otolaryngology residents.

METHODS

A web-based survey was administered to U.S. otolaryngology residents. Responses to the Shirom-Melamed Burnout Measure (SMBM) and the Generalized Anxiety Disorder-7 scale were recorded along with data on burnout, demographics, wellness, sleep, training, and education.

RESULTS

119 U.S. otolaryngology residents representing 27 of 42 states with otolaryngology residency programs responded to the survey. 24.4% (95% CI 17.0-31.8%) self-reported some level of burnout, while 10.9% met SMBM criteria for "clinically relevant" burnout. 51.3% experienced more stress, and 58.8% reported more anxiety during the COVID-19 pandemic. Compared to males, females had a higher prevalence of burnout (38.9% vs 12.3%, P = .001) and anxiety (75.9% vs 43.8%, P < .001). PGY-2s had a greater mean SMBM index (3.64) and higher rates of self-reported burnout (54.2%) than their counterparts at other levels of training. Residents reported less time spent in the hospital, lower surgical volume, and less procedural independence. Educational didactics, primarily via videoconference, were more frequent for 63.9% of respondents.

CONCLUSION

While burnout among otolaryngology residents was low early in the COVID-19 pandemic, likely due to separation from the workplace environment, trainees had higher levels of anxiety and stress. The surgical experience was negatively impacted by the pandemic, but remote didactics and educational opportunities increased. These findings may inform otolaryngology residency programs on the need to promote resident wellness and aid in devising strategies to improve the educational experience during this unique global health crisis as well as in the long term.

Coronavirus 2019 and People Living With Human Immunodeficiency Virus: Outcomes for Hospitalized Patients in New York City

BACKGROUND

There are limited data regarding the clinical impact of coronavirus disease 2019 (COVID-19) on people living with human immunodeficiency virus (PLWH). In this study, we compared outcomes for PLWH with COVID-19 to a matched comparison group.

METHODS

We identified 88 PLWH hospitalized with laboratory-confirmed COVID-19 in our hospital system in New York City between 12 March and 23 April 2020. We collected data on baseline clinical characteristics, laboratory values, HIV status, treatment, and outcomes from this group and matched comparators (1 PLWH to up to 5 patients by age, sex, race/ethnicity, and calendar week of infection). We compared clinical characteristics and outcomes (death, mechanical ventilation, hospital discharge) for these groups, as well as cumulative incidence of death by HIV status.

RESULTS

Patients did not differ significantly by HIV status by age, sex, or race/ethnicity due to the matching algorithm. PLWH hospitalized with COVID-19 had high proportions of HIV virologic control on antiretroviral therapy. PLWH had greater proportions of smoking (P < .001) and comorbid illness than uninfected comparators. There was no difference in COVID-19 severity on admission by HIV status (P = .15). Poor outcomes for hospitalized PLWH were frequent but similar to proportions in comparators; 18% required mechanical ventilation and 21% died during follow-up (compared with 23% and 20%, respectively). There was similar cumulative incidence of death over time by HIV status (P = .94).

CONCLUSIONS

We found no differences in adverse outcomes associated with HIV infection for hospitalized COVID-19 patients compared with a demographically similar patient group.

Blood Donation and COVID-19: Reconsidering the 3-Month Deferral Policy for Gay, Bisexual, Transgender, and Other Men Who Have Sex With Men

In April 2020, in light of COVID-19-related blood shortages, the US Food and Drug Administration (FDA) reduced the deferral period for men who have sex with men (MSM) from its previous duration of 1 year to 3 months.Although originally born out of necessity, the decades-old restrictions on MSM donors have been mitigated by significant advancements in HIV screening, treatment, and public education. The severity of the ongoing COVID-19 pandemic-and the urgent need for safe blood products to respond to such crises-demands an immediate reconsideration of the 3-month deferral policy for MSM.We review historical HIV testing and transmission evidence, discuss the ethical ramifications of the current deferral period, and examine the issue of noncompliance with donor deferral rules. We also propose an eligibility screening format that involves an individual risk-based screening protocol and, unlike current FDA guidelines, does not effectively exclude donors on the basis of gender identity or sexual orientation. Our policy proposal would allow historically marginalized community members to participate with dignity in the blood donation process without compromising blood donation and transfusion safety outcomes.

Contemporary approaches to high-field magnetic resonance imaging with large field inhomogeneity

Despite its importance as a clinical imaging modality, magnetic resonance imaging remains inaccessible to most of the world's population due to its high cost and infrastructure requirements. Substantial effort is underway to develop portable, low-cost systems able to address MRI access inequality and to enable new uses of MRI such as bedside imaging. A key barrier to development of portable MRI systems is increased magnetic field inhomogeneity when using small polarizing magnets, which degrades image quality through distortions and signal dropout. Many approaches address field inhomogeneity by using a low polarizing field, approximately ten to hundreds of milli-Tesla. At low-field, even a large relative field inhomogeneity of several thousand parts-per-million (ppm) results in resonance frequency dispersion of only 1-2 kHz. Under these conditions, with necessarily wide pulse bandwidths, fast spin-echo sequences may be used at low field with negligible subject heating, and a broad range of other available imaging sequences can be implemented. However, high-field MRI, 1.5 T or greater, can provide substantially improved signal-to-noise ratio and image contrast, so that higher spatial resolution, clinical quality images may be acquired in significantly less time than is necessary at low-field. The challenge posed by small, high-field systems is that the relative field inhomogeneity, still thousands of ppm, becomes tens of kilohertz over the imaging volume. This article describes the physical consequences of field inhomogeneity on established gradient- and spin-echo MRI sequences, and suggests ways to reduce signal dropout and image distortion from field inhomogeneity. Finally, the practicality of currently available image contrasts is reviewed when imaging with a high magnetic field with large inhomogeneity.

MRI exploiting frequency-modulated pulses and their nonlinear phase

Frequency-modulated (FM) pulses can provide several advantages over conventional amplitude-modulated pulses in the field of MRI; however, the manner in which spins are manipulated imprints a quadratic phase on the resulting magnetization. Historically this was considered a hindrance and slowed the widespread adoption of FM pulses. This article seeks to provide a historical perspective of the different techniques that researchers have used to exploit the benefits of FM pulses and to compensate for the nonlinear phase created by this class of pulses in MRI. Expanding on existing techniques, a new method of phase compensation is presented that utilizes nonlinear gradients to mitigate the undesirable phase imparted by this class of pulses.

In-hospital stroke after transcatheter aortic valve implantation: A UK observational cohort analysis

OBJECTIVES

We sought to identify baseline demographics and procedural factors that might independently predict in-hospital stroke following transcatheter aortic valve implantation (TAVI).

BACKGROUND

Stroke is a recognized, albeit infrequent, complication of TAVI. Established predictors of procedure-related in-hospital stroke; however, remain poorly defined.

METHODS

We conducted an observational cohort analysis of the multicenter UK TAVI registry. The primary outcome measure was the incidence of in-hospital stroke.

RESULTS

A total of 8,652 TAVI procedures were performed from 2007 to 2015. There were 205 in-hospital strokes reported by participating centers equivalent to an overall stroke incidence of 2.4%. Univariate analysis showed that the implantation of balloon-expandable valves caused significantly fewer strokes (balloon-expandable 96/4,613 [2.08%] vs. self-expandable 95/3,272 [2.90%]; p = .020). After multivariable analysis, prior cerebrovascular disease (CVD) (odds ratio [OR] 1.51, 95% confidence interval [CI 1.05-2.17]; p = .03), advanced age at time of operation (OR 1.02 [0.10-1.04]; p = .05), bailout coronary stenting (OR 5.94 [2.03-17.39]; p = .008), and earlier year of procedure (OR 0.93 [0.87-1.00]; p = .04) were associated with an increased in-hospital stroke risk. There was a reduced stroke risk in those who had prior cardiac surgery (OR 0.62 [0.41-0.93]; p = .01) and a first-generation balloon-expandable valve implanted (OR 0.72 [0.53-0.97]; p = .03). In-hospital stroke significantly increased 30-day (OR 5.22 [3.49-7.81]; p < .001) and 1-year mortality (OR 3.21 [2.15-4.78]; p < .001).

CONCLUSIONS

In-hospital stroke after TAVI is associated with substantially increased early and late mortality. Factors independently associated with in-hospital stroke were previous CVD, advanced age, no prior cardiac surgery, and deployment of a predominantly first-generation self-expandable transcatheter heart valve.

Identifying Cardiac Amyloid in Aortic Stenosis: ECV Quantification by CT in TAVR Patients

Objectives

The purpose of this study was to validate computed tomography measured ECV (ECV_CT) as part of routine evaluation for the detection of cardiac amyloid in patients with aortic stenosis (AS)-amyloid.

Background

AS-amyloid affects 1 in 7 elderly patients referred for transcatheter aortic valve replacement (TAVR). Bone scintigraphy with exclusion of a plasma cell dyscrasia can diagnose transthyretin-related cardiac amyloid noninvasively, for which novel treatments are emerging. Amyloid interstitial expansion increases the myocardial extracellular volume (ECV).

Methods

Patients with severe AS underwent bone scintigraphy (Perugini grade 0, negative; Perugini grades 1 to 3, increasingly positive) and routine TAVR evaluation CT imaging with ECV_CT using 3- and 5-min post-contrast acquisitions. Twenty non-AS control patients also had ECV_CT performed using the 5-min post-contrast acquisition.

Results

A total of 109 patients (43% male; mean age 86 ± 5 years) with severe AS and 20 control subjects were recruited. Sixteen (15%) had AS-amyloid on bone scintigraphy (grade 1, n = 5; grade 2, n = 11). ECV_CT was 32 ± 3%, 34 ± 4%, and 43 ± 6% in Perugini grades 0, 1, and 2, respectively (p < 0.001 for trend) with control subjects lower than lone AS (28 ± 2%; p < 0.001). ECV_CT accuracy for AS-amyloid detection versus lone AS was 0.87 (0.95 for ^99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid Perugini grade 2 only), outperforming conventional electrocardiogram and echocardiography parameters. One composite parameter, the voltage/mass ratio, had utility (similar AUC of 0.87 for any cardiac amyloid detection), although in one-third of patients, this could not be calculated due to bundle branch block or ventricular paced rhythm.

Conclusions

ECV_CT during routine CT TAVR evaluation can reliably detect AS-amyloid, and the measured ECV_CT tracks the degree of infiltration. Another measure of interstitial expansion, the voltage/mass ratio, also performed well.

Prevalence and outcome of dual aortic stenosis and cardiac amyloid pathology in patients referred for transcatheter aortic valve implantation

AIMS

Cardiac amyloidosis is common in elderly patients with aortic stenosis (AS) referred for transcatheter aortic valve implantation (TAVI). We hypothesized that patients with dual aortic stenosis and cardiac amyloid pathology (AS-amyloid) would have different baseline characteristics, periprocedural and mortality outcomes.

METHODS AND RESULTS

Patients aged ≥75 with severe AS referred for TAVI at two sites underwent blinded bone scintigraphy prior to intervention (Perugini Grade 0 negative, 1-3 increasingly positive). Baseline assessment included echocardiography, electrocardiogram (ECG), blood tests, 6-min walk test, and health questionnaire, with periprocedural complications and mortality follow-up. Two hundred patients were recruited (aged 85 ± 5 years, 50% male). AS-amyloid was found in 26 (13%): 8 Grade 1, 18 Grade 2. AS-amyloid patients were older (88 ± 5 vs. 85 ± 5 years, P = 0.001), with reduced quality of life (EQ-5D-5L 50 vs. 65, P = 0.04). Left ventricular wall thickness was higher (14 mm vs. 13 mm, P = 0.02), ECG voltages lower (Sokolow-Lyon 1.9 ± 0.7 vs. 2.5 ± 0.9 mV, P = 0.03) with lower voltage/mass ratio (0.017 vs. 0.025 mV/g/m2, P = 0.03). High-sensitivity troponin T and N-terminal pro-brain natriuretic peptide were higher (41 vs. 21 ng/L, P < 0.001; 3702 vs. 1254 ng/L, P = 0.001). Gender, comorbidities, 6-min walk distance, AS severity, prevalence of disproportionate hypertrophy, and post-TAVI complication rates (38% vs. 35%, P = 0.82) were the same. At a median follow-up of 19 (10-27) months, there was no mortality difference (P = 0.71). Transcatheter aortic valve implantation significantly improved outcome in the overall population (P < 0.001) and in those with AS-amyloid (P = 0.03).

CONCLUSIONS

AS-amyloid is common and differs from lone AS. Transcatheter aortic valve implantation significantly improved outcome in AS-amyloid, while periprocedural complications and mortality were similar to lone AS, suggesting that TAVI should not be denied to patients with AS-amyloid.

Dynamic multicoil technique (DYNAMITE) MRI on human brain

PURPOSE

Spatial encoding for MRI is generally based on linear x, y, and z magnetic field gradients generated by a set of dedicated gradient coils. We recently introduced the dynamic multicoil technique (DYNAMITE) for B₀ field control and demonstrated DYNAMITE MRI in a preclinical MR environment. In this study, we report the first realization of DYNAMITE MRI of the in vivo human head.

METHODS

Gradient fields for DYNAMITE MRI were generated with a 28-channel multicoil hardware arranged in 4 rows of 7 coils on a cylindrical surface (length 359 mm, diameter 344 mm, maximum 5 A per coil). DYNAMITE MRIs of a resolution phantom and in vivo human heads were acquired with multislice gradient-echo, multislice spin-echo, and 3D gradient-echo sequences. The resultant image fidelity was compared to that obtained with conventional gradient coil technology.

RESULTS

DYNAMITE field control enabled the realization of all imaging sequences with average gradient errors ≤ 1%. DYNAMITE MRI provided image quality and sensitivity comparable to conventional gradient technology without any obvious artifacts. Some minor geometric deformations were noticed primarily in the image periphery as the result of regional field imperfections. The imperfections can be readily approximated theoretically through numerical integration of the Biot-Savart law and removed through image distortion correction.

CONCLUSION

The first realization of DYNAMITE MRI of the in vivo human head has been presented. The obtained image fidelity is comparable to MRI with conventional gradient coils, paving the way for full-fledged DYNAMITE MRI and B₀ shim systems for human applications.

DPD Quantification in Cardiac Amyloidosis: A Novel Imaging Biomarker

OBJECTIVES

To assess whether single-photon emission computed tomography (SPECT/CT) quantification of bone scintigraphy would improve diagnostic accuracy and offer a means of quantifying amyloid burden.

BACKGROUND

Transthyretin-related cardiac amyloidosis is common and can be diagnosed noninvasively using bone scintigraphy; interpretation, however, relies on planar images. SPECT/CT imaging offers 3-dimensional visualization.

METHODS

This was a single-center, retrospective analysis of 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scans reported using the Perugini grading system (0 = negative; 1 to 3 = increasingly positive). Conventional planar quantification techniques (heart/contralateral lung, and heart/whole-body retention ratios) were performed. Heart, adjacent vertebra, paraspinal muscle and liver peak standardized uptake values (SUVpeak) were recorded from SPECT/CT acquisitions. An SUV retention index was also calculated: (cardiac SUVpeak/vertebral SUVpeak) × paraspinal muscle SUVpeak. In a subgroup of patients, SPECT/CT quantification was compared with myocardial extracellular volume quantification by CT imaging (ECVCT).

RESULTS

A total of 100 DPD scans were analyzed (patient age 84 ± 9 years; 52% male): 40 were Perugini grade 0, 12 were grade 1, 41 were grade 2, and 7 were grade 3. Cardiac SUVpeak increased from grade 0 to grade 2; however, it plateaued between grades 2 and 3 (p < 0.001). Paraspinal muscle SUVpeak increased with grade (p < 0.001), whereas vertebral SUVpeak decreased (p < 0.001). The composite parameter of SUV retention index overcame the plateauing of the cardiac SUVpeak and increased across all grades (p < 0.001). Cardiac SUVpeak correlated well (r2 = 0.73; p < 0.001) with ECVCT. Both the cardiac SUVpeak and SUV retention index had excellent diagnostic accuracy (area under the curve [AUC]: 0.999). The heart to contralateral lung ratio performed the best of the planar quantification techniques (AUC: 0.987).

CONCLUSIONS

SPECT/CT quantification in DPD scintigraphy is possible and outperforms planar quantification techniques. Differentiation of Perugini grade 2 or 3 is confounded by soft tissue uptake, which can be overcome by a composite SUV retention index. This index can help in the diagnosis of cardiac amyloidosis and may offer a means of monitoring response to therapy.

Transcatheter aortic valve implantation via surgical subclavian versus direct aortic access: A United Kingdom analysis

BACKGROUND

Surgical subclavian (SC) and direct aortic (DA) access are established alternatives to the default transfemoral route for transcatheter aortic valve implantation (TAVI). We sought to find differences in survival and procedure-related outcomes after SC- versus DA-TAVI.

METHODS

We performed an observational cohort analysis of cases prospectively uploaded to the UK TAVI registry. To ensure the most contemporaneous comparison, the analysis focused on SC and DA procedures performed from 2013 to 2015.

RESULTS

Between January 2013 and July 2015, 82 (37%) SC and 142 (63%) DA cases were performed that had validated 1-year life status. Multivariable regression analysis showed procedure duration was longer for SC cases (SC 193.5 ± 65.8 vs. DA 138.4 ± 57.7 min; p < .01) but length of hospital stay was shorter (SC 8.6 ± 9.5 vs. DA 11.9 ± 10.8 days; p = .03). Acute kidney injury was observed less frequently after SC cases (odds ratio [OR] 0.35, 95% confidence interval [CI 0.12-0.96]; p = .042) but vascular access site-related complications were more common (OR 9.75 [3.07-30.93]; p < .01). Procedure-related bleeding (OR 0.54 [0.24-1.25]; p = .15) and in-hospital stroke rate (SC 3.7% vs. DA 2.1%; p = .67) were similar. There were no significant differences in in-hospital (SC 2.4% vs. DA 4.9%; p = .49), 30-day (SC 2.4% vs. DA 4.2%; p = .71) or 1-year (SC 14.5% vs. DA 21.9%; p = .344) mortality.

CONCLUSIONS

Surgical subclavian and direct aortic approaches can offer favourable outcomes in appropriate patients. Neither access modality conferred a survival advantage but there were significant differences in procedural metrics that might influence which approach is selected.

Irbesartan in Marfan syndrome (AIMS): a double-blind, placebo-controlled randomised trial

BACKGROUND

Irbesartan, a long acting selective angiotensin-1 receptor inhibitor, in Marfan syndrome might reduce aortic dilatation, which is associated with dissection and rupture. We aimed to determine the effects of irbesartan on the rate of aortic dilatation in children and adults with Marfan syndrome.

METHODS

We did a placebo-controlled, double-blind randomised trial at 22 centres in the UK. Individuals aged 6-40 years with clinically confirmed Marfan syndrome were eligible for inclusion. Study participants were all given 75 mg open label irbesartan once daily, then randomly assigned to 150 mg of irbesartan (increased to 300 mg as tolerated) or matching placebo. Aortic diameter was measured by echocardiography at baseline and then annually. All images were analysed by a core laboratory blinded to treatment allocation. The primary endpoint was the rate of aortic root dilatation. This trial is registered with ISRCTN, number ISRCTN90011794.

FINDINGS

Between March 14, 2012, and May 1, 2015, 192 participants were recruited and randomly assigned to irbesartan (n=104) or placebo (n=88), and all were followed for up to 5 years. Median age at recruitment was 18 years (IQR 12-28), 99 (52%) were female, mean blood pressure was 110/65 mm Hg (SDs 16 and 12), and 108 (56%) were taking β blockers. Mean baseline aortic root diameter was 34·4 mm in the irbesartan group (SD 5·8) and placebo group (5·5). The mean rate of aortic root dilatation was 0·53 mm per year (95% CI 0·39 to 0·67) in the irbesartan group compared with 0·74 mm per year (0·60 to 0·89) in the placebo group, with a difference in means of -0·22 mm per year (-0·41 to -0·02, p=0·030). The rate of change in aortic Z score was also reduced by irbesartan (difference in means -0·10 per year, 95% CI -0·19 to -0·01, p=0·035). Irbesartan was well tolerated with no observed differences in rates of serious adverse events.

INTERPRETATION

Irbesartan is associated with a reduction in the rate of aortic dilatation in children and young adults with Marfan syndrome and could reduce the incidence of aortic complications.

FUNDING

British Heart Foundation, the UK Marfan Trust, the UK Marfan Association.

Accelerated imaging with segmented 2D pulses using parallel imaging and virtual coils

Large magnetic field inhomogeneity can be a significant cause of spatial flip-angle variation when using ordinary, limited-bandwidth RF pulses. Multidimensional RF pulses are particularly sensitive to inhomogeneity due to their extended pulse length, which decreases their bandwidth. Previously, it was shown that, by breaking a 2D pulse into multiple undersampled k-space segments, the excitation bandwidth can be increased at the expense of increased imaging time. The present study shows how this increased imaging time can be offset by undersampling acquisition k-space in a phase-encoded dimension that is in the direction of excitation segmentation. Data from each segment are viewed as originating from "virtual receive coils" rather than multiple physical coils. The undersampled data are reconstructed using parallel imaging techniques (e.g. as in GRAPPA). The method was tested in vivo with brain imaging at both 3 T and 4 T, and used in conjunction with a 32-channel head coil and conventional GRAPPA on the 3 T data. Relationships with existing techniques and future applications are discussed.