Examining lack of referrals to heart valve specialists as mechanisms of potential underutilization of aortic valve replacement.

BACKGROUND: Recent studies suggest that aortic valve replacement (AVR) remains underutilized. AIMS: Investigate the potential role of non-referral to heart valve specialists (HVS) on AVR utilization. METHODS: Patients with severe aortic stenosis (AS) between 2015 and 2018, who met class I indication for intervention, were identified. Baseline data and process-related parameters were collected to analyze referral predictors and evaluate outcomes. RESULTS: Among 981 patients meeting criteria AVR, 790 patients (80.5%) were assessed by HVS within six months of index TTE. Factors linked to reduced referral included increasing age (OR: 0.95; 95% CI: 0.94-0.97; P < .001), unmarried status (OR: 0.59; 95% CI: 0.43-0.83; P = .002) and inpatient TTE (OR: 0.27; 95% CI: 0.19-0.38; P < .001). Conversely, higher hematocrit (OR: 1.13; 95% CI: 1.09-1.16; P < .001) and eGFR (OR: 1.01; 95% CI: 1.00-1.02; P = .003), mean aortic valve gradient (OR: 1.03; 95% CI: 1.01-1.04; P < .001) and preserved LVEF (OR: 1.59; 95% CI: 1.02-2.48; P = .04), were associated with increased referral likelihood. Moreover, patients assessed by HVS referral as a time-dependent covariate had a significantly lower two-year mortality risk than those who were not (aHR: 0.30; 95% CI: 0.23-0.39; P < .001). CONCLUSION: A substantial proportion of severe AS patients meeting indications for AVR are not evaluated by HVS and experience markedly increased mortality. Further research is warranted to assess the efficacy of care delivery mechanisms, such as e-consults, and telemedicine, to improve access to HVS expertise.

Traversing Excitonic and Ionic Landscapes: Reduced-Dimensionality-Inspired Design of Organometal Halide Semiconductors for Energy Applications.

At the very heart of the global semiconductor industry lies the omnipresent push for new materials discovery. New materials constantly rise and fall out of fashion in the scientific literature, with those passing an initial phase of research scrutiny becoming hotbeds of characterization and optimization efforts. Yet, innumerable hours of painstaking research have been devoted to materials that have ultimately fallen by the wayside after crossing over an indefinable threshold, whereupon historical optimism is met with newfound skepticism. Materials have to perform well, and they have to do it quickly. In the past decade, metal-halide perovskites (MHPs) have garnered widespread attention. The hegemonic view in both academic and industrial circles is that these materials could be engineered to meet the demands of the semiconductor industry. Their promise as inexpensive solar cell devices is highly attractive, and it has been nothing short of remarkable that efficiencies have risen from 3.8% in 2009 to more than 25.5% in 2021. Moreover, MHPs are poised to be revolutionary materials in more ways than one. The highest MHP LED efficiency was recently reported (23.4%), and MHPs have demonstrated promise in photodetectors, memristors, and transistors. However, the many excellent properties of MHPs are contrasted by longstanding stability and reproducibility limitations that have hindered their commercialization. Overcoming the limitations of MHPs is ultimately a materials engineering problem, which should be solved by mapping more precise relationships between structure, composition, and device performance. In 1958, Francis Crick famously developed the central dogma of molecular biology which describes the unidirectional flow of information in biological systems. In the words of Crick, "nature has devised a unique instrument in which an underlying simplicity is used to express great subtlety and versatility." In this Account, taking inspiration from the hierarchical organization of nature, we describe a hierarchical approach to materials engineering of organic metal-halide semiconductors. We demonstrate that organo-metal halide semiconductors' dimensionality, composition, and morphology dictate their optoelectronic properties and can be exploited in defining more explicit relationships between structure and function. Here, we traverse three-dimensional (3D), two-dimensional (2D), and one-dimensional (1D) organo-metal halide semiconductors, detailing the morphological and compositional differences in each and the implications that can be drawn within each domain on the engineering process. Control over ion migration pathways via morphology engineering as well as control over charge formation in organic-inorganic semiconductors is demonstrated. Fundamental insights into the amount of static and dynamic disorder in the MHP lattice are provided, which can be continuously tuned as a function of composition and morphology. Using electroabsorption spectroscopy on 2D MHPs, a disorder-induced dipole moment in the exciton proportional to the summed value of static and dynamic disorder is measured. Spectroscopic isolation of exciton features in 2D MHP electroabsorption spectra allows us to obtain precise, model-independent measurements of exciton binding energies to study the effect of chemical substitutions, such as Sn2+ → Pb2+, on the value of the exciton binding energy. Finally, we conclude that this multidimensional platform, with the aid of machine learning and robotics, will be foundational in accurately predicting structure-property-device relationships in organo-metal halide semiconductors in the future.

Impact of bleeding after transcatheter aortic valve replacement in patients with chronic kidney disease.

OBJECTIVE: In patients with chronic kidney disease (CKD) undergoing transcatheter aortic valve replacement (TAVR), this study aims to elucidate (a) the bleeding risks associated with CKD, (b) the association between bleeding and subsequent mortality, and (c) the pattern of antithrombotic therapy prescribed. BACKGROUND: Patients with CKD have a higher risk of bleeding following TAVR. It is unclear whether this risk persists beyond the periprocedural period and whether it negatively impacts mortality. METHODS: A retrospective review was performed on patients who underwent TAVR at Massachusetts General Hospital from 2008 to 2017. CKD was defined as estimated glomerular filtration rate less than 60 ml/min/1.73 m2 . Primary endpoints up to 1-year following TAVR included bleeding, all-cause mortality, and ischemic stroke. Outcomes for patients with and without CKD were compared using log-rank test, and Cox regression with age, sex, and diabetes as covariates. Bleeding was treated as a time-varying covariate, and Cox proportional hazard regression was utilized to model mortality. RESULTS: Of the 773 patients analyzed, 466 (60.3%) had CKD. At 1 year, CKD patients had higher rates of bleeding (9.2 vs. 4.9%, adjusted hazard ratios [aHR] = 1.91, p = .032) and all-cause mortality (13.7 vs. 9.1%, aHR = 1.57, p = .049), but not stroke (3.9 vs. 1.6% aHR = 0.073, p = .094). Bleeding was associated with an increased risk of subsequent mortality (aHR = 2.65, 95% CI: 1.25-5.63, p = .01). There were no differences in the antithrombotic strategy following TAVR between CKD and non-CKD patients. CONCLUSION: CKD is associated with a higher risk of bleeding up to 1 year following TAVR. Long-term bleeding after TAVR is associated with increased subsequent mortality.

Understanding Hydrogen Bonding Interactions in Crosslinked Methylammonium Lead Iodide Crystals: Towards Reducing Moisture and Light Degradation Pathways.

Methylammonium lead halide perovskite-based solar cells have demonstrated efficiencies as high as 24.2 %, highlighting their potential as inexpensive and solution-processable alternatives to silicon solar cell technologies. Poor stability towards moisture, ultraviolet irradiation, heat, and a bias voltage of the perovskite layer and its various device interfaces limits the commercial feasibility of this material for outdoor applications. Herein, we investigate the role of hydrogen bonding interactions induced when metal halide perovskite crystals are crosslinked with alkyl or π-conjugated boronic acid small molecules (-B(OH)2 ). The crosslinked perovskite crystals are investigated under continuous light irradiation and moisture exposure. These studies demonstrate that the origin of the interaction between the alkyl or π-conjugated crosslinking molecules is due to hydrogen bonding between the -B(OH)2 terminal group of the crosslinker and the I of the [PbI6 ]4- octahedra of the perovskite layer. Also, this interaction influences the stability of the perovskite layer towards moisture and ultraviolet light irradiation. Morphology and structural analyses, as well as IR studies as a function of aging under both dark and light conditions show that π-conjugated boronic acid molecules are more effective crosslinkers of the perovskite crystals than their alkyl counterparts thus imparting better stability towards light and moisture degradation.

Impact of Decision Aid on Decision-making of Patients With Severe Aortic Stenosis: Randomized Pilot Study.

Background: Clinical guidelines recommend patients with aortic stenosis (AS) being considered for transcatheter aortic valve implantation or surgical aortic valve replacement to participate in shared decision-making (SDM) with a heart valve team (HVT). Data supporting these recommendations are limited. This project gathered data on feasibility and preliminary efficacy of a decision aid (DA) in decision-making for patients with severe AS deciding between transcatheter aortic valve implantation and surgical aortic valve replacement. Methods: This institutional review board-approved randomized pilot trial assigned eligible patients to receive either the American College of Cardiology's DA for patients with AS or usual care. Patients were surveyed after their visit regarding knowledge, treatment-preference concordance, SDM (SDM process and CollaboRATE Scales), and decisional conflict. Patients were followed for 3 months to collect data on treatment received. Results: Of 62 patients approached, 59 (95%) consented and participated. The average age of participants was 72 years, they were 100% white, and 32% of them were female. Intervention patients had higher knowledge scores (75.6 vs 65.5) and more frequently reported CollaboRATE top scores (67% vs 33%) than usual care patients. No other group comparisons reached significance. Patients who saw both members of the HVT before survey completion reported higher SDM process scores than those who saw only 1 specialist (3.1 vs 2.4). Conclusions: The study exceeded enrollment targets, indicating feasibility. Results suggest the American College of Cardiology's DA improved patient knowledge and communication scores. Patients who met with both members of the HVT reported higher SDM. These observations highlight the importance of SDM and multidisciplinary HVT assessment in the management of severe AS.

Establishing Self-Dopant Design Principles from Structure-Function Relationships in Self-n-Doped Perylene Diimide Organic Semiconductors.

Self-doping is a particular doping method that has been applied to a wide range of organic semiconductors. However, there is a lack of understanding regarding the relationship between dopant structure and function. A structurally diverse series of self-n-doped perylene diimides (PDIs) is investigated to study the impact of steric encumbrance, counterion selection, and dopant/PDI tether distance on functional parameters such as doping, stability, morphology, and charge-carrier mobility. The studies show that self-n-doping is best enabled by the use of sterically encumbered ammoniums with short tethers and Lewis basic counterions. Additionally, water is found to inhibit doping, which concludes that thermal degradation is merely a phenomenological feature of certain dopants, and that residual solvent evaporation is the primary driver of thermally activated doping. In situ grazing-incidence wide-angle X-ray scattering studies show that sample annealing increases the π-π stacking distance and shrinks grain boundaries for improved long-range ordering. These features are then correlated to contactless carrier-mobility measurements with time-resolved microwave conductivity before and after thermal annealing. The collective relationships between structural features and functionality are finally used to establish explicit self-n-dopant design principles for the future design of materials with improved functionality.

Patient- and Process-Related Contributors to the Underuse of Aortic Valve Replacement and Subsequent Mortality in Ambulatory Patients With Severe Aortic Stenosis.

Background Many patients with severe aortic stenosis (AS) and an indication for aortic valve replacement (AVR) do not undergo treatment. The reasons for this have not been well studied in the transcatheter AVR era. We sought to determine how patient- and process-specific factors affected AVR use in patients with severe AS. Methods and Results We identified ambulatory patients from 2016 to 2018 demonstrating severe AS, defined by aortic valve area [Formula: see text]1.0 cm2. Propensity scoring analysis with inverse probability of treatment weighting was used to evaluate associations between predictors and the odds of undergoing AVR at 365 days and subsequent mortality at 730 days. Of 324 patients with an indication for AVR (79.3±9.7 years, 57.4% men), 140 patients (43.2%) did not undergo AVR. The odds of AVR were reduced in patients aged >90 years (odds ratio [OR], 0.24 [95% CI, 0.08-0.69]; P=0.01), greater comorbid conditions (OR, 0.88 per 1-point increase in Combined Comorbidity Index [95% CI, 0.79-0.97]; P=0.01), low-flow, low-gradient AS with preserved left ventricular ejection fraction (OR, 0.11 [95% CI, 0.06-0.21]), and low-gradient AS with reduced left ventricular ejection fraction (OR, 0.18 [95% CI, 0.08-0.40]) and were increased if the transthoracic echocardiogram ordering provider was a cardiologist (OR, 2.46 [95% CI, 1.38-4.38]). Patients who underwent AVR gained an average of 85.8 days of life (95% CI, 40.9-130.6) at 730 days. Conclusions The proportion of ambulatory patients with severe AS and an indication for AVR who do not receive AVR remains significant. Efforts are needed to maximize the recognition of severe AS, especially low-gradient subtypes, and to encourage patient referral to multidisciplinary heart valve teams.

Trends in Utilization of Aortic Valve Replacement for Severe Aortic Stenosis.

BACKGROUND: Despite the rapid growth of aortic valve replacement (AVR) for aortic stenosis (AS), limited data suggest symptomatic severe AS remains undertreated. OBJECTIVES: This study sought to investigate temporal trends in AVR utilization among patients with a clinical indication for AVR. METHODS: Patients with severe AS (aortic valve area <1 cm2) on transthoracic echocardiograms from 2000 to 2017 at 2 large academic medical centers were classified based on clinical guideline indications for AVR and divided into 4 AS subgroups: high gradient with normal left ventricular ejection fraction (LVEF) (HG-NEF), high gradient with low LVEF (HG-LEF), low gradient with normal LVEF (LG-NEF), and low gradient with low LVEF (LG-LEF). Utilization of AVR was examined and predictors identified. RESULTS: Of 10,795 patients, 6,150 (57%) had an indication or potential indication for AVR, of whom 2,977 (48%) received AVR. The frequency of AVR varied by AS subtype with LG groups less likely to receive an AVR (HG-NEF: 70%, HG-LEF: 53%, LG-NEF: 32%, LG-LEF: 38%, P < 0.001). AVR volumes grew over the 18-year study period but were paralleled by comparable growth in the number of patients with an indication for AVR. In patients with a Class I indication, younger age, coronary artery disease, smoking history, higher hematocrit, outpatient index transthoracic echocardiogram, and LVEF ≥0.5 were independently associated with an increased likelihood of receiving an AVR. AVR was associated with improved survival in each AS-subgroup. CONCLUSIONS: Over an 18-year period, the proportion of patients with an indication for AVR who did not receive AVR has remained substantial despite the rapid growth of AVR volumes.

Dual Antiplatelet Therapy: How Long Is Long Enough?

PURPOSE OF REVIEW: The optimal duration of dual antiplatelet therapy (DAPT) has been a topic of considerable interest in recent years, as the risk of stent thrombosis has decreased with newer generation stents and the impact of significant bleeding events on clinical outcomes is increasingly apparent. The purpose of this review is to highlight the landmark studies examining short-duration (6 months or less) and extended-duration (greater than 12 months) DAPT as well as provide information about prediction tools to help guide individualized patient treatment decisions. RECENT FINDINGS: Short-duration DAPT is acceptably safe when clinically necessary, though recent trials demonstrate non-significant trends towards increased risk of ischemic events with shorter durations. Extended-duration DAPT clearly confers a reduced risk of subsequent ischemic events but at an increased risk of bleeding. Understanding the perceived ischemic and bleeding risks for each individual patient is paramount in deciding targeted DAPT duration. For patients at a higher bleeding risk with a low ischemic risk, short-duration DAPT (6 months) is acceptable. For patients with continued ischemic risk factors and a low bleeding risk, extended-duration DAPT (up to 30 months) is recommended. The PRECISE DAPT and DAPT prediction tools are helpful in making this determination.

Subclinical Burden of Coronary Artery Calcium in Patients With Coarctation of the Aorta.

Coronary computed tomography (CT) angiography is often performed in adults with coarctation of the aorta (CoA) for anatomic assessment. As this population ages, assessment of atherosclerotic cardiovascular disease burden is important. Thus, quantitative and qualitative coronary artery calcium (CAC) scores were assessed for patients with CoA ≥16 years of age, who were seen at a referral center. CoA patients had either coronary CT angiography or chest CT with interpretable coronary information performed for clinical indications (follow-up, preoperative, or for symptoms) from 2004 to 2017. Qualitative CAC was determined based on low-dose CT and lung cancer screening protocols. Quantitative CAC scores were compared with an age- and gender-matched control cohort of patients chosen from an emergency department database of patients who received coronary CT angiography for chest pain evaluation. Atherosclerotic cardiovascular disease 10-year predicted risk scores were calculated for both cohorts. Out of 131 patients with CoA (mean age 46.1 ± 15.3 years), 22 patients (17%) had multivessel atherosclerotic disease on qualitative assessment. In the subgroup of patients ≥40 years, those with CoA were more likely to have a quantitative CAC score ≥400 compared with those without CoA (14% vs 4%, p = 0.02). Median atherosclerotic cardiovascular disease risk score was 8% (interquartile range 2% to 12%) for CoA patients ≥40 years, and 5% (interquartile range 2% to 9%) for patient without CoA ≥40 years. In conclusion, we determined that CoA patients have subclinical atherosclerosis identifiable on CT in high rates when compared with patients without CoA. Atherosclerotic cardiovascular disease should be assessed in these patients for prevention and treatment.

Frequency of Guideline-Based Statin Therapy in Adults With Congenital Heart Disease.

We aimed to evaluate atherosclerotic cardiovascular disease (ASCVD) risk estimates and guideline-based statin use for primary prevention of ASCVD in adults with congenital heart disease (ACHD). This was a case-controlled, retrospective study of 248 cases and 744 age- and gender-matched controls at a tertiary care referral center. ASCVD risk scores were calculated and used to assess indication for statin treatment for primary prevention per the 2013 American College of Cardiology and American Heart Association guideline on assessment of cardiovascular risk. There were no differences in average 10-year ASCVD risk scores between ACHD cases (4.6% ± 6.6%) and matched controls (5.1% ± 6.7%, p = 0.32). ACHD cases had lower total cholesterol (183 ± 38 vs 192.6 ± 35.3 mg/dL, p < 0.001) and were less likely to smoke (8.1% vs 14.6%, p = 0.008), yet had lower high density lipoprotein (52.6 ± 17.2 vs 55.3 ± 17.1 mg/dL, p = 0.03) and higher hypertension rates (38.7% vs 28.5%, p = 0.003). However, only 42.3% ACHD cases with a primary prevention statin indication were appropriately prescribed therapy as compared with 59.0% of controls (p = 0.04). In conclusion, ACHD cases have a similar 10-year ASCVD risk score than age- and gender-matched peers, but ACHD cases are less likely than their peers to be prescribed statin therapy for primary prevention per guideline-based recommendations.

Transseptal mitral valve replacement after transcatheter aortic valve implantation.

We report a case of mitral valve replacement in a patient who had previously undergone transcatheter aortic valve implantation. A transseptal approach was used to avoid displacing the aortic prosthesis. Because of the small mitral annulus, a bioprosthetic aortic valve was used in reverse position for mitral valve replacement. The procedure did not interfere with the existing prosthesis, and a follow-up echocardiogram showed that both prosthetic valves were functioning well.To the best of our knowledge, this is the first report of mitral valve replacement in a patient who had a preceding transcatheter aortic valve implantation. We believe that the transseptal approach is promising for mitral valve replacement in such patients. Moreover, using a bioprosthetic aortic valve in reverse position is an option for mitral valve replacement when the mitral annulus is too small for placement of a standard bioprosthetic mitral valve.