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ObjectiveWe addressed the paucity of data describing the characteristics and consequences of incident aortic stenosis (AS).MethodsAdults undergoing echocardiography with a native aortic valve (AV) and no AS were studied. Subsequent age-specific and sex-specific incidence of AS were derived from echocardiograms conducted a median of 2.8 years apart. Progressive AV dysfunction and individually linked mortality were examined per AS category.Results49 449 men (53.9%, 60.9±15.8 years) and 42 229 women (61.6±16.9 years) with no initial evidence of AS were identified. Subsequently, 6293 (6.9%) developed AS—comprising 5170 (5.6%), 636 (0.7%), 339 (0.4%) and 148 (0.2%) cases of mild, moderate, severe low-gradient and severe high-gradient AS, respectively. Age-adjusted incidence rates of all grades of AS were 17.5 cases per 1000 men/annum and 18.7 cases per 1000 women/annum: rising from ~5 to ~40 cases per 1000/annum in those aged <30 years vs >80 years. Median peak AV velocity increased by +0.57 (+0.36 to +0.80) m/s in mild AS compared with +2.75 (+2.40 to +3.19) m/s in severe high-gradient AS cases between first and last echocardiograms. During subsequent median 7.7 years follow-up, 24 577 of 91 678 cases (26.8%) died. Compared with no AS, the adjusted risk of all-cause mortality was 1.42-fold higher in mild AS, 1.92-fold higher in moderate AS, 1.95-fold higher in severe low-gradient AS and 2.27-fold higher in severe, high-gradient AS cases (all p<0.001).ConclusionsNew onset AS is a common finding among older patients followed up with echocardiography. Any grade of AS is associated with higher mortality, reinforcing the need for proactive vigilance.

Our understanding of the causes and consequences of pulmonary hypertension is limited. Consequently, its most distinctive forms with the worst prognosis have been the focus for diagnosis and treatment. We highlight the emerging challenge of reframing the prevalence and prognostic implications of pulmonary hypertension, focusing on the optimal therapeutic window to address the high mortality linked to this condition.

Body surface area (BSA) is the most commonly used metric for body size indexation of echocardiographic measures, but its use in patients who are underweight or obese is questioned (body mass index (BMI) < 18.5 kg/m 2 or ≥ 30 kg/m 2 , respectively). We aim to use survival analysis to identify an optimal body size indexation metric for echocardiographic measures that would be a better predictor of survival than BSA regardless of BMI. Adult patients with no prior valve replacement were selected from the National Echocardiography Database Australia. Survival analysis was performed for echocardiographic measures both unindexed and indexed to different body size metrics, with 5-year cardiovascular mortality as the primary endpoint. Indexation of echocardiographic measures (left ventricular end-diastolic diameter [n = 230,109] and mass [n = 224,244], left atrial volume [n = 150,540], aortic sinus diameter [n = 90,805], right atrial area [n = 59,516]) by BSA had better prognostic performance vs unindexed measures (underweight: C-statistic 0.655 vs 0.647; normal weight/overweight: average C-statistic 0.666 vs 0.625; obese: C-statistic 0.627 vs 0.613). Indexation by other body size metrics (lean body mass, height, and/or weight raised to different powers) did not improve prognostic performance versus BSA by a clinically relevant magnitude (average C-statistic increase ≤ 0.02), with smaller differences in other BMI subgroups. Indexing measures of cardiac and aortic size by BSA improves prognostic performance regardless of BMI, and no other body size metric has a clinically meaningful better performance.

ObjectiveTo estimate the population prevalence and treatable burden of severe aortic stenosis (AS) in the UK.MethodsWe adapted a contemporary model of the population profile of symptomatic and asymptomatic severe AS in Europe and North America to estimate the number of people aged ≥55 years in the UK who might benefit from surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI).ResultsWith a point prevalence of 1.48%, we estimate that 291 448 men and women aged ≥55 years in the UK had severe AS in 2019. Of these, 68.3% (199 059, 95% CI 1 77 201 to 221 355 people) would have been symptomatic and, therefore, more readily treated according to their surgical risk profile; the remaining 31.7% of cases (92 389, 95% CI 70 093 to 144 247) being asymptomatic. Based on historical patterns of intervention, 58.4% (116 251, 95% CI 106 895 to 1 25 606) of the 199 059 symptomatic cases would qualify for SAVR, with 7208 (95% CI 7091 to 7234) being assessed as being in a high, preoperative surgical risk category. Among the remaining 41.6% (82 809, 95% CI 73 453 to 92 164) of cases potentially unsuitable for SAVR, an estimated 61.7% (51 093, 95% CI 34 780 to 67 655) might be suitable for TAVI. We estimate that 172 859 out of 291 448 prevalent cases of severe AS (59.3%) will subsequently die within 5 years without proactive management.ConclusionsThese data suggest a high burden of severe AS in the UK requiring surgical or transcatheter intervention that challenges the ongoing capacity of the National Health Service to meet the needs of those affected.

Decreased hydraulic forces during diastole contribute to reduced left ventricular (LV) filling and heart failure with preserved ejection fraction. However, their association with diastolic function and patient outcomes are unknown. The aim of this retrospective, cross-sectional study was to determine the mechanistic association between diastolic hydraulic forces, estimated by echocardiography as the atrioventricular area difference (AVAD), and both diastolic function and survival. Patients (n = 5176, median [interquartile range] 5.5 [5.0–6.1] years follow-up, 1213 events) were selected from the National Echo Database Australia (NEDA) based on the presence of relevant transthoracic echocardiographic measures, LV ejection fraction (LVEF) ≥ 50%, heart rate 50–100 beats/minute, the absence of moderate or severe valvular disease, and no prior prosthetic valve surgery. NEDA contains echocardiographic and linked national death index mortality outcome data from 1985 to 2019. AVAD was calculated as the cross-sectional area difference between the LV and left atrium. LV diastolic dysfunction was graded according to 2016 guidelines. AVAD was weakly associated with E/e’, left atrial volume index, and LVEF (multivariable global R 2  = 0.15, p  < 0.001), and not associated with e’ and peak tricuspid regurgitation velocity. Decreased AVAD was independently associated with poorer survival, and demonstrated improved model discrimination after adjustment for diastolic function grading (C-statistic [95% confidence interval] 0.644 [0.629–0.660] vs 0.606 [0.592–0.621], p  < 0.001) and E/e’ (0.649 [0.635–0.664] vs 0.634 [0.618–0.649], p  < 0.001), respectively. Therefore, decreased hydraulic forces, estimated by AVAD, are weakly associated with diastolic dysfunction and demonstrate an incremental prognostic association with survival beyond conventional measures used to grade diastolic dysfunction.

Background Sex‐specific differences in left ventricular ejection fraction (LVEF) and responses to neurohormonal modulating therapies are relevant to clinical trials of treatment for heart failure with preserved ejection fraction (HFpEF). Aims This study aimed to identify the proportion and characteristics of patients presenting with possible or confirmed HFpEF within the National Echo Database of Australia. Results A total of 237 046 women (48.1%) and 256 019 men (aged 61.0 ± 18.3 vs. 60.6 ± 17.1 years, respectively) had sex‐specific distributions of LVEF: 94.3% of women had LVEF ≥ 45% (mean LVEF 66.0 ± 8.6%), compared with 87.2% of men (mean LVEF 63.4 ± 8.7%). The presence of structural heart disease (SHD) according to the PARAGON‐HF criteria could be calculated in 93.8% of women and 93.4% of men with an LVEF ≥ 45%. Of these, 64 502 (30.8%) women and 104 344 (50.0%) of men had left ventricular hypertrophy, and 78 948 (35.3%) and 95 846 (42.9%), respectively, had left atrial enlargement. As a result, the proportion of women vs. men fulfilling echocardiographic criteria for HFpEF was very different: 111 497 (53.2%) vs. 146 359 (70.1%). SHD markedly increased with age, associated with a greater increase in women than men. The same signal was observed in those referred for suspected or previously confirmed HFpEF. Conclusions Double the number of men than women had LVEF < 45%, and the distribution of SHD had was highly sex specific. Left ventricular hypertrophy and left atrial enlargement were more common in men and becoming more frequent in women with advancing age. The echocardiographic SHD distribution was similar in those referred with suspected or confirmed HFpEF. The findings are relevant to sex‐specific recruitment criteria for future clinical trials.

Tissue engineering offers a paradigm shift in the treatment of back pain. Engineered intervertebral discs could replace degenerated tissue and overcome the limitations of current treatments that disrupt the biomechanics of the spine. New materials, which exhibit sophisticated mechanical responses, are needed to provide templates for tissue regeneration. These behaviours include time-dependent deformation---facilitating shock absorption and nutrient transfer---and strong material anisotropy and tensile-compressive nonlinearities---providing flexibility in controlled directions. In this work, frameworks for the design of materials with controllable structure-property relationships are developed. The time-dependent mechanical properties of composites of agar, alginate and gelatin hydrogels are investigated. It is shown that the time-dependent responses of the composites can be tuned over a wide range. It is then demonstrated that materials mimicking the fibre-reinforced nature of natural tissues can be developed by infiltrating thick electrospun fibre networks with alginate. These fibre-reinforced hydrogels have tensile and compressive properties that can be separately altered. To better understand the mechanical behaviour of these hydrogel-based materials, improved methods for characterising poroelastic and poroviscoelastic time-dependent material properties using indentation are developed. It is shown that poroviscoelastic relaxation is the product of separate poroelastic and viscoelastic relaxation responses. The techniques developed here provide a methodology to rapidly characterise the properties of time-dependent materials and to create materials with complex structure-property relationships similar to those found in natural tissues; they present a framework for biomimetic materials design. The work in this thesis can be used to inform the design of clinically relevant tissue engineering treatments and help the quarter of a million people each year who undergo spinal surgery to reduce back pain.

OBJECTIVES: To determine the association between diastolic hydraulic forces, estimated by echocardiography as the atrioventricular area difference (AVAD), and both diastolic function and survival. We hypothesized that decreased diastolic hydraulic forces, estimated as AVAD, would associate with survival independent of conventional diastolic dysfunction measures. BACKGROUND: Decreased hydraulic forces during diastole contribute to reduced left ventricular (LV) filling and heart failure with preserved ejection fraction. However, their association with diastolic function and patient outcomes are unknown. METHODS: Patients (n=11,734, median [interquartile range] 3.9 [2.4-5.0] years follow-up, 1,213 events) were selected from the National Echo Database Australia based on the presence of relevant transthoracic echocardiographic measures, LV ejection fraction (LVEF) greater than or equal to 50%, heart rate 50-100 beats/minute, the absence of moderate or severe valvular disease, and no prior cardiac surgery. AVAD was calculated as the cross-sectional area difference between the LV and left atrium. LV diastolic dysfunction was graded according to 2016 guidelines. RESULTS: AVAD was weakly associated with E/e prime, left atrial volume index, and LVEF (multivariable global R2=0.15, p<0.001), and not associated with e prime and peak tricuspid regurgitation velocity. Decreased AVAD was independently associated with poorer survival, and demonstrated improved model discrimination after adjustment for diastolic function grading (C-statistic [95% confidence interval] 0.645 [0.629-0.662] vs 0.607 [0.592-0.623], p<0.001) and E/e prime (0.639 [0.623-0.655] vs 0.621 [0.604-0.637], p<0.001), respectively. CONCLUSIONS: Decreased hydraulic forces, estimated by AVAD, are weakly associated with diastolic dysfunction and demonstrate an incremental prognostic association with survival beyond conventional measures used to grade diastolic dysfunction. Competing Interest Statement D.P. has received modest honorarium from Alerte Echo IQ. The study was funded in part by grants to M.U. from New South Wales Health, Heart Research Australia, and the University of Sydney. The remaining authors declare that they have no competing interests. Funding Statement This research was supported in part by grants (PI Ugander) from New South Wales Health, Heart Research Australia, and the University of Sydney. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study complies with the Declaration of Helsinki, and has received approval from the lead ethics committee at the Royal Prince Alfred Hospital, Camperdown, Sydney, Australia (2019/ETH06989), and the human research ethics committees of all participating centers in Australia I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data Availability All data produced in the present work are contained in the manuscript (unless otherwise specified). Supplementary data in the present study is available upon reasonable request to the authors.

One of the characteristics of severe emphysema is hyperinflation of regions of the lungs. In this trial, valves that prevented air entry but allowed air to escape were placed in lobar airways. Patients receiving endobronchial valves had modest improvements in lung function and exercise performance. Emphysema is a leading cause of disability and death. Lung-volume–reduction surgery, in which selected areas of hyperinflated lungs are resected, improves exercise tolerance and prolongs life in selected patients. However, concern regarding the risk of perioperative death and complications contributes to underutilization. 1 – 4 Less invasive bronchoscopic techniques that are based on the presumed physiological effects of lung-volume–reduction surgery have been developed. 5 – 10 Early uncontrolled trials using unidirectional valves placed in selected lung airways to block regional inflation while allowing exhalation have reported improvements in lung function and symptoms with modest risk, including distal pneumonia or pneumothorax. 5 , 6 , 9 , 11 – . . .