Economic Outcomes of Transcatheter Versus Surgical Aortic Valve Replacement in Patients with Severe Aortic Stenosis and Low Surgical Risk: Results from the PARTNER 3 Trial.

BACKGROUND: In patients with severe symptomatic aortic stenosis at low surgical risk, transfemoral transcatheter aortic valve replacement (TAVR) with the SAPIEN 3 valve has been shown to reduce the composite of death, stroke, or rehospitalization at 2-year follow-up compared with surgical aortic valve replacement (SAVR). Whether TAVR is cost-effective compared with SAVR for low-risk patients remains uncertain. METHODS: Between 2016 and 2017, 1000 low-risk patients with aortic stenosis were randomly assigned to TAVR with the SAPIEN 3 valve or SAVR in the PARTNER 3 trial (Placement of Aortic Transcatheter Valves). Of these patients, 929 underwent valve replacement, were enrolled in the United States, and were included in the economic substudy. Procedural costs were estimated using measured resource use. Other costs were determined by linkage with Medicare claims or by regression models when linkage was not feasible. Health utilities were estimated using the EuroQOL 5-item questionnaire. With the use of a Markov model informed by in-trial data, lifetime cost-effectiveness from the perspective of the US health care system was estimated in terms of cost per quality-adjusted life-year gained. RESULTS: Although procedural costs were nearly $19 000 higher with TAVR, total index hospitalization costs were only $591 more with TAVR compared with SAVR. Follow-up costs were lower with TAVR such that TAVR led to 2-year cost savings of $2030/patient compared with SAVR (95% CI, -$6222 to $1816) and a gain of 0.05 quality-adjusted life-years (95% CI, -0.003 to 0.102). In our base-case analysis, TAVR was projected to be an economically dominant strategy with a 95% probability that the incremental cost-effectiveness ratio for TAVR would be <$50 000/quality-adjusted life-year gained (consistent with high economic value from a US health care perspective). These findings were sensitive to differences in long-term survival, however, such that a modest long-term survival advantage with SAVR would render SAVR cost-effective (although not cost saving) compared with TAVR. CONCLUSIONS: For patients with severe aortic stenosis and low surgical risk similar to those enrolled in the PARTNER 3 trial, transfemoral TAVR with the SAPIEN 3 valve is cost saving compared with SAVR at 2 years and is projected to be economically attractive in the long run as long as there are no substantial differences in late death between the 2 strategies. Long-term follow-up will be critical to ultimately determine the preferred treatment strategy for low-risk patients from both a clinical and economic perspective.

Membranous Septum Length Predicts New Conduction Abnormalities in Surgical Aortic Valve Replacement: A Novel Predictor for Permanent Pacemaker Implantation After Surgical Aortic Valve Replacement.

INTRODUCTION: The membranous septum (MS) length measured by cardiac computed tomography (CT) is useful for the prediction of permanent pacemaker implantation (PPMI) and new left bundle branch block (LBBB) after transcatheter aortic valve replacement. However, its predictive value for patients undergoing surgical aortic valve replacement (SAVR) is unknown. METHODS: A total of 2531 consecutive patients were registered in the institutional Society of Thoracic Surgeons database between July 2017 and June 2020. Patients who underwent non-SAVR procedures, had prior pacemaker/implantable cardioverter defibrillator, prior SAVR, no preprocedural CT assessment, or suboptimal CT imaging were excluded. RESULTS: A total of 126 SAVR with preprocedural CT assessment were analyzed. Bicuspid aortic valve morphology was confirmed on CT in 59.5% of patients. There were three new PPMIs and five new LBBBs observed after SAVR at the time of discharge. In-hospital mortality was 0.8%. Low left ventricular (LV) ejection fraction (<50%), LV mass index >120 g/m2, large right coronary artery height, and MS length <1.5 mm predicted new PPMI/LBBB. Multivariate analysis showed LV mass index >120 g/m2 (odds ratio: 9.165; 95% confidence interval: 1.644-51.080; P = 0.011) and MS length <1.5 mm (odds ratio: 14.449; 95% confidence interval: 1.632-127.954; P = 0.016) were independent predictors for new PPMI/LBBB. CONCLUSIONS: Short MS length on preoperative cardiac CT is a powerful and novel predictor for the risk of new PPMI/LBBB after SAVR. Special care should be taken in patients with short MS length to avoid suture-mediated trauma.

Five-Year Outcomes of Transcatheter or Surgical Aortic-Valve Replacement.

BACKGROUND: There are scant data on long-term clinical outcomes and bioprosthetic-valve function after transcatheter aortic-valve replacement (TAVR) as compared with surgical aortic-valve replacement in patients with severe aortic stenosis and intermediate surgical risk. METHODS: We enrolled 2032 intermediate-risk patients with severe, symptomatic aortic stenosis at 57 centers. Patients were stratified according to intended transfemoral or transthoracic access (76.3% and 23.7%, respectively) and were randomly assigned to undergo either TAVR or surgical replacement. Clinical, echocardiographic, and health-status outcomes were followed for 5 years. The primary end point was death from any cause or disabling stroke. RESULTS: At 5 years, there was no significant difference in the incidence of death from any cause or disabling stroke between the TAVR group and the surgery group (47.9% and 43.4%, respectively; hazard ratio, 1.09; 95% confidence interval [CI], 0.95 to 1.25; P = 0.21). Results were similar for the transfemoral-access cohort (44.5% and 42.0%, respectively; hazard ratio, 1.02; 95% CI, 0.87 to 1.20), but the incidence of death or disabling stroke was higher after TAVR than after surgery in the transthoracic-access cohort (59.3% vs. 48.3%; hazard ratio, 1.32; 95% CI, 1.02 to 1.71). At 5 years, more patients in the TAVR group than in the surgery group had at least mild paravalvular aortic regurgitation (33.3% vs. 6.3%). Repeat hospitalizations were more frequent after TAVR than after surgery (33.3% vs. 25.2%), as were aortic-valve reinterventions (3.2% vs. 0.8%). Improvement in health status at 5 years was similar for TAVR and surgery. CONCLUSIONS: Among patients with aortic stenosis who were at intermediate surgical risk, there was no significant difference in the incidence of death or disabling stroke at 5 years after TAVR as compared with surgical aortic-valve replacement. (Funded by Edwards Lifesciences; PARTNER 2 ClinicalTrials.gov number, NCT01314313.).

Avoiding emissions versus creating sinks-Effectiveness and attractiveness to climate finance.

The perception of greater impact via new sinks, as opposed to through avoided emissions, has already led some large investors to focus on sink-related projects. This is a flawed perception when applied universally and carries a risk that effective routes to mitigation through avoiding emissions are side-lined. In reality, both emissions avoidance and emissions removal are needed, and both can be a cost-effective means of delivering mitigation.

Global net biome CO2 exchange predicted comparably well using parameter-environment relationships and plant functional types.

Accurate estimation and forecasts of net biome CO2 exchange (NBE) are vital for understanding the role of terrestrial ecosystems in a changing climate. Prior efforts to improve NBE predictions have predominantly focused on increasing models' structural realism (and thus complexity), but parametric error and uncertainty are also key determinants of model skill. Here, we investigate how different parameterization assumptions propagate into NBE prediction errors across the globe, pitting the traditional plant functional type (PFT)-based approach against a novel top-down, machine learning-based "environmental filtering" (EF) approach. To do so, we simulate these contrasting methods for parameter assignment within a flexible model-data fusion framework of the terrestrial carbon cycle (CARDAMOM) at a global scale. In the PFT-based approach, model parameters from a small number of select locations are applied uniformly within regions sharing similar land cover characteristics. In the EF-based approach, a pixel's parameters are predicted based on underlying relationships with climate, soil, and canopy properties. To isolate the role of parametric from structural uncertainty in our analysis, we benchmark the resulting PFT-based and EF-based NBE predictions with estimates from CARDAMOM's Bayesian optimization approach (whereby "true" parameters consistent with a suite of data constraints are retrieved on a pixel-by-pixel basis). When considering the mean absolute error of NBE predictions across time, we find that the EF-based approach matches or outperforms the PFT-based approach at 55% of pixels-a narrow majority. However, NBE estimates from the EF-based approach are susceptible to compensation between errors in component flux predictions and predicted parameters can align poorly with the assumed "true" values. Overall, though, the EF-based approach is comparable to conventional approaches and merits further investigation to better understand and resolve these limitations. This work provides insight into the relationship between terrestrial biosphere model performance and parametric uncertainty, informing efforts to improve model parameterization via PFT-free and trait-based approaches.

Across-model spread and shrinking in predicting peatland carbon dynamics under global change.

Large across-model spread in simulating land carbon (C) dynamics has been ubiquitously demonstrated in model intercomparison projects (MIPs), and became a major impediment in advancing climate change prediction. Thus, it is imperative to identify underlying sources of the spread. Here, we used a novel matrix approach to analytically pin down the sources of across-model spread in transient peatland C dynamics in response to a factorial combination of two atmospheric CO2 levels and five temperature levels. We developed a matrix-based MIP by converting the C cycle module of eight land models (i.e., TEM, CENTURY4, DALEC2, TECO, FBDC, CASA, CLM4.5 and ORCHIDEE) into eight matrix models. While the model average of ecosystem C storage was comparable to the measurement, the simulation differed largely among models, mainly due to inter-model difference in baseline C residence time. Models generally overestimated net ecosystem production (NEP), with a large spread that was mainly attributed to inter-model difference in environmental scalar. Based on the sources of spreads identified, we sequentially standardized model parameters to shrink simulated ecosystem C storage and NEP to almost none. Models generally captured the observed negative response of NEP to warming, but differed largely in the magnitude of response, due to differences in baseline C residence time and temperature sensitivity of decomposition. While there was a lack of response of NEP to elevated CO2 (eCO2 ) concentrations in the measurements, simulated NEP responded positively to eCO2 concentrations in most models, due to the positive responses of simulated net primary production. Our study used one case study in Minnesota peatland to demonstrate that the sources of across-model spreads in simulating transient C dynamics can be precisely traced to model structures and parameters, regardless of their complexity, given the protocol that all the matrix models were driven by the same gross primary production and environmental variables.

Transesophageal Echocardiographic Screening for Structural Heart Interventions.

PURPOSE OF REVIEW: Percutaneous structural interventions have provided patients with an effective therapeutic option, and its growth has been aided by echocardiography. We describe the vital role that transesophageal echocardiography (TEE) plays in screening patients prior to their procedure. RECENT FINDINGS: A multimodality imaging approach is employed by the valve team, but TEE plays a unique role in diagnosis and planning. Utilization of all TEE views and features such as biplane, 3D imaging, and multiplanar reconstruction ensures accurate assessment of the structural lesion of interest. The role of TEE remains essential in the planning of structural interventions, and these studies should be performed in a systematic and comprehensive manner.

Controlled Trial of Budesonide-Formoterol as Needed for Mild Asthma.

BACKGROUND: In double-blind, placebo-controlled trials, budesonide-formoterol used on an as-needed basis resulted in a lower risk of severe exacerbation of asthma than as-needed use of a short-acting ß2-agonist (SABA); the risk was similar to that of budesonide maintenance therapy plus as-needed SABA. The availability of data from clinical trials designed to better reflect clinical practice would be beneficial. METHODS: We conducted a 52-week, randomized, open-label, parallel-group, controlled trial involving adults with mild asthma. Patients were randomly assigned to one of three treatment groups: albuterol (100 µg, two inhalations from a pressurized metered-dose inhaler as needed for asthma symptoms) (albuterol group); budesonide (200 µg, one inhalation through a Turbuhaler twice daily) plus as-needed albuterol (budesonide maintenance group); or budesonide-formoterol (200 µg of budesonide and 6 µg of formoterol, one inhalation through a Turbuhaler as needed) (budesonide-formoterol group). Electronic monitoring of inhalers was used to measure medication use. The primary outcome was the annualized rate of asthma exacerbations. RESULTS: The analysis included 668 of 675 patients who underwent randomization. The annualized exacerbation rate in the budesonide-formoterol group was lower than that in the albuterol group (absolute rate, 0.195 vs. 0.400; relative rate, 0.49; 95% confidence interval [CI], 0.33 to 0.72; P<0.001) and did not differ significantly from the rate in the budesonide maintenance group (absolute rate, 0.195 in the budesonide-formoterol group vs. 0.175 in the budesonide maintenance group; relative rate, 1.12; 95% CI, 0.70 to 1.79; P = 0.65). The number of severe exacerbations was lower in the budesonide-formoterol group than in both the albuterol group (9 vs. 23; relative risk, 0.40; 95% CI, 0.18 to 0.86) and the budesonide maintenance group (9 vs. 21; relative risk, 0.44; 95% CI, 0.20 to 0.96). The mean (±SD) dose of inhaled budesonide was 107±109 µg per day in the budesonide-formoterol group and 222±113 µg per day in the budesonide maintenance group. The incidence and type of adverse events reported were consistent with those in previous trials and with reports in clinical use. CONCLUSIONS: In an open-label trial involving adults with mild asthma, budesonide-formoterol used as needed was superior to albuterol used as needed for the prevention of asthma exacerbations. (Funded by AstraZeneca and the Health Research Council of New Zealand; Novel START Australian New Zealand Clinical Trials Registry number, ACTRN12615000999538.).

Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients.

BACKGROUND: Among patients with aortic stenosis who are at intermediate or high risk for death with surgery, major outcomes are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. There is insufficient evidence regarding the comparison of the two procedures in patients who are at low risk. METHODS: We randomly assigned patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve or surgery. The primary end point was a composite of death, stroke, or rehospitalization at 1 year. Both noninferiority testing (with a prespecified margin of 6 percentage points) and superiority testing were performed in the as-treated population. RESULTS: At 71 centers, 1000 patients underwent randomization. The mean age of the patients was 73 years, and the mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk of death within 30 days after the procedure). The Kaplan-Meier estimate of the rate of the primary composite end point at 1 year was significantly lower in the TAVR group than in the surgery group (8.5% vs. 15.1%; absolute difference, -6.6 percentage points; 95% confidence interval [CI], -10.8 to -2.5; P<0.001 for noninferiority; hazard ratio, 0.54; 95% CI, 0.37 to 0.79; P = 0.001 for superiority). At 30 days, TAVR resulted in a lower rate of stroke than surgery (P = 0.02) and in lower rates of death or stroke (P = 0.01) and new-onset atrial fibrillation (P<0.001). TAVR also resulted in a shorter index hospitalization than surgery (P<0.001) and in a lower risk of a poor treatment outcome (death or a low Kansas City Cardiomyopathy Questionnaire score) at 30 days (P<0.001). There were no significant between-group differences in major vascular complications, new permanent pacemaker insertions, or moderate or severe paravalvular regurgitation. CONCLUSIONS: Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery. (Funded by Edwards Lifesciences; PARTNER 3 ClinicalTrials.gov number, NCT02675114.).

Single dose of budesonide/formoterol turbuhaler compared to salbutamol pMDI for speed of bronchodilator onset in asthma: a randomised cross-over trial.

OBJECTIVE: To compare bronchodilator response after to salbutamol and budesonide/formoterol in adults with stable asthma. METHODS: A double-blind, cross-over, single-centre, placebo-controlled, non-inferiority trial. Adults with stable asthma were randomised to different orders of two treatment regimens: two actuations of placebo via MDI and one actuation of budesonide/formoterol 200/6 µg via turbuhaler; and one actuation of placebo turbuhaler and two actuations of salbutamol 100 µg via MDI. The primary outcome measure was FEV1 after 2 min. Secondary outcome measures included FEV1, mBorg Dyspnoea Scale score and visual analogue score for breathlessness over 30 min. RESULTS: Forty-nine of 50 potential participants were randomised. One participant withdrew following the first intervention visit and another could not be randomised due to COVID-19 restrictions. The mean (SD) change from baseline FEV1 2 min after treatment administration for budesonide/formoterol and salbutamol was 0.08 (0.14) L, n=49, and 0.17 (0.18) L, n=48, respectively, mean (95% CI) paired difference of -0.097 L (-0.147 to -0.047), p=0.07, against a non-inferiority bound of -0.06 L. In the secondary analysis, FEV1 over 30 min was lower for budesonide/formoterol compared with salbutamol, difference (95% CI): -0.10 (-0.12 to -0.08) L, p<0.001. There were no differences in Visual Analogue Scale score or mBorg Dyspnoea Scale score between treatments. CONCLUSION: The results do not support the primary hypothesis of non-inferiority at the boundary of -0.06 L for the difference between budesonide/formoterol 200/6 µg compared with salbutamol 200 µg for FEV1 at 2 min, and could be consistent with inferiority with a p value of 0.07. For the secondary analysis of FEV1 measurements over time, the FEV1 was higher with salbutamol. TRIAL REGISTRATION NUMBER: Australian and New Zealand Clinical Trials Registry (ACTRN 12619001387112).

Repeated dose budesonide/formoterol compared to salbutamol in adult asthma: A randomised cross-over trial.

OBJECTIVE: To determine the comparative bronchodilator, systemic beta2-agonist, cardiovascular and adverse effects of salbutamol 200 µg and budesonide/formoterol 200/6 µg when taken repeatedly in stable asthma. METHODS: This open-label, cross-over, single-centre, controlled trial, randomised adults with asthma to different orders of two treatment regimens: salbutamol 200 µg via MDI at t=0, 30, 60, 90 min, then salbutamol 2.5 mg via nebuliser at t=120, 140, 160 and 420 min; or budesonide/formoterol 200/6 µg one actuation via Turbuhaler at t=0, 30, 60, 90 min, two actuations at t=120, 140, 160 and 420 min. The primary outcome measure was FEV1 after 180 min. Secondary outcomes included repeat measures of FEV1, serum potassium, heart rate, and adverse events RESULTS: Of 39 patients randomised, two withdrew due to adverse events (QTCF prolongation and T wave abnormalities) after the first intervention with salbutamol. The mean (sd) change from baseline FEV1 180 min after randomisation for salbutamol and budesonide/formoterol regimens was 0.71 (0.46) L, N=38, and 0.58 (0.45) L, N=37, respectively; with a mean (sd) paired difference of -0.10 (0.40) L, N=37, and a model-based estimated difference (95% CI) -0.12 (-0.25 to 0.02) L, p=0.088. In the main secondary analysis, salbutamol resulted in significantly greater FEV1 from 30 to 240 min, but lesser FEV1 at 360 and 420 min. Salbutamol resulted in a significantly lower serum potassium, and a higher heart rate and number of adverse events. CONCLUSION: The comparative bronchodilator responses of repeated administration of salbutamol 200 µg dose-1 and budesonide/formoterol 200/6 µg differed depending on the time of measurement. Salbutamol caused greater systemic beta2-agonist and cardiovascular effects and more adverse events.

Bacterial endocarditis with AACEK (HACEK) organisms.

INTRODUCTION: Gram-negative organisms of the AACEK group, formerly known as HACEK, rarely cause endocarditis. CASE SERIES: We present three cases of bacterial endocarditis, involving native and prosthetic valves, caused by AACEK organisms. In two patients, Cardiobacterium hominis was the responsible organism, and in a third, Aggregatibacter aphrophilus was implicated. A dental source of infection was identified in two patients, and in all three patients, the presentation of endocarditis was subacute. DISCUSSION: This case series highlights the indolent nature of infection with the AACEK organisms. It also demonstrates the crucial role of multimodality imaging, especially transesophageal echocardiography, in the diagnosis of AACEk endocarditis of both native and prosthetic valves, and in delineating the extent of abscess in those with prosthetic valve infection.

Inhaled JAK inhibitor GDC-0214 reduces exhaled nitric oxide in patients with mild asthma: A randomized, controlled, proof-of-activity trial.

BACKGROUND: The Janus kinase (JAK) pathway mediates the activity of many asthma-relevant cytokines, including IL-4 and IL-13. GDC-0214 is a potent, inhaled, small-molecule JAK inhibitor being developed for the treatment of asthma. OBJECTIVE: We sought to determine whether GDC-0214 reduces fractional exhaled nitric oxide (Feno), a JAK1-dependent biomarker of airway inflammation, in patients with mild asthma. METHODS: We conducted a double-blind, randomized, placebo-controlled, phase 1 proof-of-activity study in adults with mild asthma and Feno higher than 40 parts per billion (ppb). Subjects were randomized 2:1 (GDC-0214:placebo) into 4 sequential ascending-dose cohorts (1 mg once daily [QD], 4 mg QD, 15 mg QD, or 15 mg twice daily). All subjects received 4 days of blinded placebo, then 10 days of either active drug or placebo. The primary outcome was placebo-corrected percent reduction in Feno from baseline to day 14. Baseline was defined as the average Feno during the blinded placebo period. Pharmacokinetics, safety, and tolerability were also assessed. RESULTS: Thirty-six subjects (mean age, 28 years; 54% females) were enrolled. Mean Feno at baseline across all subjects was 93 ± 43 ppb. At day 14, placebo-corrected difference in Feno was -23% (95% CI, -37.3 to -9) for 15 mg QD and -42% (95% CI, -57 to -27.4) for 15 mg twice daily. Higher plasma exposure was associated with greater Feno reduction. No dose-limiting adverse events, serious adverse events, or treatment discontinuations occurred. There were no major imbalances in adverse events or laboratory findings, or evidence of systemic JAK inhibition. CONCLUSIONS: GDC-0214, an inhaled JAK inhibitor, caused dose-dependent reductions in Feno in mild asthma and was well tolerated without evidence of systemic toxicity.

Echocardiographic Results of Transcatheter Versus Surgical Aortic Valve Replacement in Low-Risk Patients: The PARTNER 3 Trial.

BACKGROUND: This study aimed to compare echocardiographic findings in low-risk patients with severe aortic stenosis after surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR). METHODS: The PARTNER 3 trial (Placement of Aortic Transcatheter Valves) randomized 1000 patients with severe aortic stenosis and low surgical risk to undergo either transfemoral TAVR with the balloon-expandable SAPIEN 3 valve or SAVR. Transthoracic echocardiograms obtained at baseline and at 30 days and 1 year after the procedure were analyzed by a consortium of 2 echocardiography core laboratories. RESULTS: The percentage of moderate or severe aortic regurgitation (AR) was low and not statistically different between the TAVR and SAVR groups at 30 days (0.8% versus 0.2%; P=0.38). Mild AR was more frequent after TAVR than SAVR at 30 days (28.8% versus 4.2%; P<0.001). At 1 year, mean transvalvular gradient (13.7±5.6 versus 11.6±5.0 mm Hg; P=0.12) and aortic valve area (1.72±0.37 versus 1.76±0.42 cm2; P=0.12) were similar in TAVR and SAVR. The percentage of severe prosthesis-patient mismatch at 30 days was low and similar between TAVR and SAVR (4.6 versus 6.3%; P=0.30). Valvulo-arterial impedance (Zva), which reflects total left ventricular hemodynamic burden, was lower with TAVR than SAVR at 1 year (3.7±0.8 versus 3.9±0.9 mm Hg/mL/m2; P<0.001). Tricuspid annulus plane systolic excursion decreased and the percentage of moderate or severe tricuspid regurgitation increased from baseline to 1 year in SAVR but remained unchanged in TAVR. Irrespective of treatment arm, high Zva and low tricuspid annulus plane systolic excursion, but not moderate to severe AR or severe prosthesis-patient mismatch, were associated with increased risk of the composite end point of mortality, stroke, and rehospitalization at 1 year. CONCLUSIONS: In patients with severe aortic stenosis and low surgical risk, TAVR with the SAPIEN 3 valve was associated with similar percentage of moderate or severe AR compared with SAVR but higher percentage of mild AR. Transprosthetic gradients, valve areas, percentage of severe prosthesis-patient mismatch, and left ventricular mass regression were similar in TAVR and SAVR. SAVR was associated with significant deterioration of right ventricular systolic function and greater tricuspid regurgitation, which persisted at 1 year. High Zva and low tricuspid annulus plane systolic excursion were associated with worse outcome at 1 year whereas AR and severe prosthesis-patient mismatch were not. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02675114.

Structural diversity and tree density drives variation in the biodiversity-ecosystem function relationship of woodlands and savannas.

Positive biodiversity-ecosystem function relationships (BEFRs) have been widely documented, but it is unclear if BEFRs should be expected in disturbance-driven systems. Disturbance may limit competition and niche differentiation, which are frequently posited to underlie BEFRs. We provide the first exploration of the relationship between tree species diversity and biomass, one measure of ecosystem function, across southern African woodlands and savannas, an ecological system rife with disturbance from fire, herbivores and humans. We used > 1000 vegetation plots distributed across 10 southern African countries and structural equation modelling to determine the relationship between tree species diversity and above-ground woody biomass, accounting for interacting effects of resource availability, disturbance by fire, tree stem density and vegetation type. We found positive effects of tree species diversity on above-ground biomass, operating via increased structural diversity. The observed BEFR was highly dependent on organismal density, with a minimum threshold of c. 180 mature stems ha-1 . We found that water availability mainly affects biomass indirectly, via increasing species diversity. The study underlines the close association between tree diversity, ecosystem structure, environment and function in highly disturbed savannas and woodlands. We suggest that tree diversity is an under-appreciated determinant of wooded ecosystem structure and function.

Does economic optimisation explain LAI and leaf trait distributions across an Amazon soil moisture gradient?

Leaf area index (LAI) underpins terrestrial ecosystem functioning, yet our ability to predict LAI remains limited. Across Amazon forests, mean LAI, LAI seasonal dynamics and leaf traits vary with soil moisture stress. We hypothesise that LAI variation can be predicted via an optimality-based approach, using net canopy C export (NCE, photosynthesis minus the C cost of leaf growth and maintenance) as a fitness proxy. We applied a process-based terrestrial ecosystem model to seven plots across a moisture stress gradient with detailed in situ measurements, to determine nominal plant C budgets. For each plot, we then compared observations and simulations of the nominal (i.e. observed) C budget to simulations of alternative, experimental budgets. Experimental budgets were generated by forcing the model with synthetic LAI timeseries (across a range of mean LAI and LAI seasonality) and different leaf trait combinations (leaf mass per unit area, lifespan, photosynthetic capacity and respiration rate) operating along the leaf economic spectrum. Observed mean LAI and LAI seasonality across the soil moisture stress gradient maximised NCE, and were therefore consistent with optimality-based predictions. Yet, the predictive power of an optimality-based approach was limited due to the asymptotic response of simulated NCE to mean LAI and LAI seasonality. Leaf traits fundamentally shaped the C budget, determining simulated optimal LAI and total NCE. Long-lived leaves with lower maximum photosynthetic capacity maximised simulated NCE under aseasonal high mean LAI, with the reverse found for short-lived leaves and higher maximum photosynthetic capacity. The simulated leaf trait LAI trade-offs were consistent with observed distributions. We suggest that a range of LAI strategies could be equally economically viable at local level, though we note several ecological limitations to this interpretation (e.g. between-plant competition). In addition, we show how leaf trait trade-offs enable divergence in canopy strategies. Our results also allow an assessment of the usefulness of optimality-based approaches in simulating primary tropical forest functioning, evaluated against in situ data.

Long-term outcomes after transcatheter aortic valve replacement with minimal contrast in chronic kidney disease.

BACKGROUND: Patients with renal insufficiency have poor short-term outcomes after transcatheter aortic valve replacement (TAVR). METHODS: Retrospective chart review identified 575 consecutive patients not on hemodialysis who underwent TAVR between September 2014 and January 2017. Outcomes were defined by VARC-2 criteria. Primary outcome of all-cause mortality was evaluated at a median follow-up of 811 days (interquartile range 125-1,151). RESULTS: Preprocedural glomerular filtration rate (GFR) was ≥60 ml/min in 51.7%, 30-60 ml/min in 42.1%, and < 30 ml/min in 6.3%. Use of transfemoral access (98.8%) and achieved device success (91.0%) did not differ among groups, but less contrast was used with lower GFR (23 ml [15-33], 24 ml [14-33], 13 ml [8-20]; p < .001). Peri-procedural stroke (0.7%, 2.1%, 11.1%; p < .001) was higher with lower GFR. Core lab analysis of preprocedural computed tomography scans of patients who developed a peri-procedural stroke identified potential anatomic substrate for stroke in three out of four patients with GFR 30-60 ml/min and all three with GFR <30 ml/min (severe atheroma was the most common subtype of anatomical substrate present). Compared to GFR ≥60 ml/min, all-cause mortality was higher with GFR 30-60 ml/min (HR 1.61 [1.00-2.59]; aHR 1.61 [0.91-2.83]) and GFR <30 ml/min (HR 2.41 [1.06-5.48]; aHR 2.34 [0.90-6.09]) but not significant after multivariable adjustment. Follow-up echocardiographic data, available in 63%, demonstrated no difference in structural heart valve deterioration over time among groups. CONCLUSIONS: Patients with baseline renal insufficiency remain a challenging population with poor long-term outcomes despite procedural optimization with a transfemoral-first and an extremely low-contrast approach.

Comparison of a Complete Percutaneous Versus Surgical Approach to Aortic Valve Replacement and Revascularization in Patients at Intermediate Surgical Risk: Results From the Randomized SURTAVI Trial.

BACKGROUND: For patients with severe aortic stenosis and coronary artery disease, the completely percutaneous approach to aortic valve replacement and revascularization has not been compared with the standard surgical approach. METHODS: The prospective SURTAVI trial (Safety and Efficiency Study of the Medtronic CoreValve System in the Treatment of Severe, Symptomatic Aortic Stenosis in Intermediate Risk Subjects Who Need Aortic Valve Replacement) enrolled intermediate-risk patients with severe aortic stenosis from 87 centers in the United States, Canada, and Europe between June 2012 and June 2016. Complex coronary artery disease with SYNTAX score (Synergy Between PCI with Taxus and Cardiac Surgery Trial) >22 was an exclusion criterion. Patients were stratified according to the need for revascularization and then randomly assigned to treatment with transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). Patients assigned to revascularization in the TAVR group underwent percutaneous coronary intervention, whereas those in the SAVR group had coronary artery bypass grafting. The primary end point was the rate of all-cause mortality or disabling stroke at 2 years. RESULTS: Of 1660 subjects with attempted aortic valve implants, 332 (20%) were assigned to revascularization. They had a higher Society of Thoracic Surgeons risk score for mortality (4.8±1.7% versus 4.4±1.5%; P<0.01) and were more likely to be male (65.1% versus 54.2%; P<0.01) than the 1328 patients not assigned to revascularization. After randomization to treatment, there were 169 patients undergoing TAVR and percutaneous coronary intervention, 163 patients undergoing SAVR and coronary artery bypass grafting, 695 patients undergoing TAVR, and 633 patients undergoing SAVR. No significant difference in the rate of the primary end point was found between TAVR and percutaneous coronary intervention and SAVR and coronary artery bypass grafting (16.0%; 95% CI, 11.1-22.9 versus 14.0%; 95% CI, 9.2-21.1; P=0.62), or between TAVR and SAVR (11.9%; 95% CI, 9.5-14.7 versus 12.3%; 95% CI, 9.8-15.4; P=0.76). CONCLUSIONS: For patients at intermediate surgical risk with severe aortic stenosis and noncomplex coronary artery disease (SYNTAX score ≤22), a complete percutaneous approach of TAVR and percutaneous coronary intervention is a reasonable alternative to SAVR and coronary artery bypass grafting. CLINICAL TRIAL REGISTRATION: URL: https://www. CLINICALTRIALS: gov. Unique identifier: NCT01586910.

Therapeutic blockade of inflammation in severe COVID-19 infection with intravenous N-acetylcysteine.

Glucose 6-phosphate dehydrogenase (G6PD) deficiency facilitates human coronavirus infection due to glutathione depletion. G6PD deficiency may especially predispose to hemolysis upon coronavirus disease-2019 (COVID-19) infection when employing pro-oxidant therapy. However, glutathione depletion is reversible by N-acetylcysteine (NAC) administration. We describe a severe case of COVID-19 infection in a G6PD-deficient patient treated with hydroxychloroquine who benefited from intravenous (IV) NAC beyond reversal of hemolysis. NAC blocked hemolysis and elevation of liver enzymes, C-reactive protein (CRP), and ferritin and allowed removal from respirator and veno-venous extracorporeal membrane oxygenator and full recovery of the G6PD-deficient patient. NAC was also administered to 9 additional respirator-dependent COVID-19-infected patients without G6PD deficiency. NAC elicited clinical improvement and markedly reduced CRP in all patients and ferritin in 9/10 patients. NAC mechanism of action may involve the blockade of viral infection and the ensuing cytokine storm that warrant follow-up confirmatory studies in the setting of controlled clinical trials.

Budesonide-formoterol reliever therapy versus maintenance budesonide plus terbutaline reliever therapy in adults with mild to moderate asthma (PRACTICAL): a 52-week, open-label, multicentre, superiority, randomised controlled trial.

BACKGROUND: In adults with mild asthma, a combination of an inhaled corticosteroid with a fast-onset long-acting ß-agonist (LABA) used as reliever monotherapy reduces severe exacerbations compared with short-acting ß-agonist (SABA) reliever therapy. We investigated the efficacy of combination budesonide-formoterol reliever therapy compared with maintenance budesonide plus as-needed terbutaline. METHODS: We did a 52-week, open-label, parallel-group, multicentre, superiority, randomised controlled trial at 15 primary care or hospital-based clinical trials units and primary care practices in New Zealand. Participants were adults aged 18-75 years with a self-reported doctor's diagnosis of asthma who were using SABA for symptom relief with or without maintenance low to moderate doses of inhaled corticosteroids in the previous 12 weeks. We randomly assigned participants (1:1) to either reliever therapy with budesonide 200 µg-formoterol 6 µg Turbuhaler (one inhalation as needed for relief of symptoms) or maintenance budesonide 200 µg Turbuhaler (one inhalation twice daily) plus terbutaline 250 µg Turbuhaler (two inhalations as needed). Participants and investigators were not masked to group assignment; the statistician was masked for analysis of the primary outcome. Six study visits were scheduled: randomisation, and weeks 4, 16, 28, 40, and 52. The primary outcome was the number of severe exacerbations per patient per year analysed by intention to treat (severe exacerbations defined as use of systemic corticosteroids for at least 3 days because of asthma, or admission to hospital or an emergency department visit because of asthma requiring systemic corticosteroids). Safety analyses included all participants who had received at least one dose of study treatment. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12616000377437. FINDINGS: Between May 4, 2016, and Dec 22, 2017, we assigned 890 participants to treatment and included 885 eligible participants in the analysis: 437 assigned to budesonide-formoterol as needed and 448 to budesonide maintenance plus terbutaline as needed. Severe exacerbations per patient per year were lower with as-needed budesonide-formoterol than with maintenance budesonide plus terbutaline as needed (absolute rate per patient per year 0·119 vs 0·172; relative rate 0·69, 95% CI 0·48-1·00; p=0·049). Nasopharyngitis was the most common adverse event in both groups, occurring in 154 (35%) of 440 patients receiving as-needed budesonide-formoterol and 144 (32%) of 448 receiving maintenance budesonide plus terbutaline as needed. INTERPRETATION: In adults with mild to moderate asthma, budesonide-formoterol used as needed for symptom relief was more effective at preventing severe exacerbations than maintenance low-dose budesonide plus as-needed terbutaline. The findings support the 2019 Global Initiative for Asthma recommendation that inhaled corticosteroid-formoterol reliever therapy is an alternative regimen to daily low-dose inhaled corticosteroid for patients with mild asthma. FUNDING: Health Research Council of New Zealand.