Executive Summary Surgical ablation for atrial fibrillation (AF) can be performed without additional risk of operative mortality or major morbidity, and is recommended at the time of concomitant ...mitral operations to restore sinus rhythm. (Class I, Level A) Surgical ablation for AF can be performed without additional operative risk of mortality or major morbidity, and is recommended at the time of concomitant isolated aortic valve replacement, isolated coronary artery bypass graft surgery, and aortic valve replacement plus coronary artery bypass graft operations to restore sinus rhythm. (Class I, Level B nonrandomized) Surgical ablation for symptomatic AF in the absence of structural heart disease that is refractory to class I/III antiarrhythmic drugs or catheter-based therapy or both is reasonable as a primary stand-alone procedure, to restore sinus rhythm. (Class IIA, Level B randomized) Surgical ablation for symptomatic persistent or longstanding persistent AF in the absence of structural heart disease is reasonable, as a stand-alone procedure using the Cox-Maze III/IV lesion set compared with pulmonary vein isolation alone. (Class IIA, Level B nonrandomized) Surgical ablation for symptomatic AF in the setting of left atrial enlargement (≥4.5 cm) or more than moderate mitral regurgitation by pulmonary vein isolation alone is not recommended. (Class III no benefit, Level C expert opinion) It is reasonable to perform left atrial appendage excision or exclusion in conjunction with surgical ablation for AF for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C limited data) At the time of concomitant cardiac operations in patients with AF, it is reasonable to surgically manage the left atrial appendage for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C expert opinion) In the treatment of AF, multidisciplinary heart team assessment, treatment planning, and long-term follow-up can be useful and beneficial to optimize patient outcomes. (Class I, Level C expert opinion)
Background This study evaluated trends and outcomes of tricuspid valve surgery (TVS) in North America over the past decade. Methods Adults undergoing TVS between 2000 and 2010 were identified in The ...Society of Thoracic Surgeons (STS) National Database. Trends were evaluated using linear regression. Multivariable logistic regression analysis was conducted using covariates from the STS valve risk model to identify significant predictors of operative mortality. Results A total of 54,375 patients underwent TVS during the study period. The majority of cases were repairs (89%; n = 48,322) and were performed concomitant with another major procedure (86%; n = 46,593). The proportion of TVS that were repairs increased from 84.6% in 2000 to 89.8% in 2010 ( p = 0.01). Trend analysis revealed significant changes in patient characteristics with time, including increasing age, a higher comorbidity burden, and a higher proportion of emergency cases. Despite worsening risk factors, unadjusted operative mortality for TVS declined from 10.6% in 2000 to 8.2% in 2010 ( p < 0.001), and this trend persisted after risk adjustment. In the multivariable model, concomitant procedures involving multiple valves or coronary artery bypass grafting were associated with an increased risk of mortality compared with isolated TVS, although other factors including renal failure, congestive heart failure, nonelective presentation, reoperation, and tricuspid valve replacement exerted equal or stronger effects. Conclusions During the past decade, repair rates for TVS have increased significantly. Although patients undergoing TVS have demonstrated worsening risk factors, unadjusted and adjusted operative mortalities have declined. Finally, the data suggest that tricuspid valve repair when technically feasible, together with early elective surgical intervention, should be emphasized as potential candidates for continued outcome improvement.
Two very basic ideas in sexual selection are heavily influenced by numbers of potential mates: the evolution of anisogamy, leading to sex role differentiation, and the frequency dependence of ...reproductive success that tends to equalize primary sex ratios. However, being explicit about the numbers of potential mates is not typical to most evolutionary theory of sexual selection. Here, we argue that this may prevent us from finding the appropriate ecological equilibria that determine the evolutionary endpoints of selection. We review both theoretical and empirical advances on how population density may influence aspects of mating systems such as intrasexual competition, female choice or resistance, and parental care. Density can have strong effects on selective pressures, whether or not there is phenotypic plasticity in individual strategies with respect to density. Mating skew may either increase or decrease with density, which may be aided or counteracted by changes in female behaviour. Switchpoints between alternative mating strategies can be density dependent, and mate encounter rates may influence mate choice (including mutual mate choice), multiple mating, female resistance to male mating attempts, mate searching, mate guarding, parental care, and the probability of divorce. Considering density-dependent selection may be essential for understanding how populations can persist at all despite sexual conflict, but simple models seem to fail to predict the diversity of observed responses in nature. This highlights the importance of considering the interaction between mating systems and population dynamics, and we strongly encourage further work in this area.
Models of population dynamics generally neglect the presence of males. While this assumption holds under many circumstances, behavioural ecology increasingly tells us that the presence (or absence) ...of males may have an impact on female fitness, and hence population sizes. Here we ask the question of whether males matter to population dynamics, operationally defined as a dependency of population growth on the relative density of males. We provide simple models, and evaluate the current empirical evidence for them, that illustrate various mechanisms of such male influence: mate searching behavior, male resource use (including effects of sexual dimorphism), sexual harassment and sexual segregation. In each case, theory predicts that males can have an effect on population densities, and in some extreme cases a positive feedback between an increasingly male-biased sex ratio and the effects on female harassment may theoretically even bring about population extinction. The results of this study, and the literature reviewed, show that the males can have a substantial effect on population dynamics, particularly so when human influences result in biased sex ratios.
Commentary: Questionable statistical routines Rankin, J. Scott
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
April 2021, 2021-04-00, 20210401, Letnik:
161, Številka:
4
Journal Article
Garrett Hardin's tragedy of the commons is an analogy that shows how individuals driven by self-interest can end up destroying the resource upon which they all depend. The proposed solutions for ...humans rely on highly advanced skills such as negotiation, which raises the question of how non-human organisms manage to resolve similar tragedies. In recent years, this question has promoted evolutionary biologists to apply the tragedy of the commons to a wide range of biological systems. Here, we provide tools to categorize different types of tragedy and review different mechanisms, including kinship, policing and diminishing returns that can resolve conflicts that could otherwise end in tragedy. A central open question, however, is how often biological systems are able to resolve these scenarios rather than drive themselves extinct through individual-level selection favouring self-interested behaviours.
There is an absence of national statistics for maternal obesity in the UK. This study is the first to describe a nationally representative maternal obesity research data set in England.
Retrospective ...epidemiological study of first trimester obesity.
Data from 34 maternity units were analysed, including 619 323 births between 1989 and 2007. Data analysis included trends in first trimester maternal body bass index status over time, and geographical distribution of maternal obesity. Population demographics including maternal age, parity, ethnic group, deprivation and employment were analysed to identify any maternal obesity-associated health inequalities. All demographics were tested for multicollinearity. Logistic regression analyses were adjusted for all demographics as confounders.
First trimester maternal obesity is significantly increasing over time, having more than doubled from 7.6% to 15.6% over 19 years (P<0.001), and shows geographic variation in incidence. There are also demographic health inequalities associated with maternal obesity, including increased odds of being obese with increasing age, parity, Black ethnic group and deprivation. There is also an association between morbid obesity and increased levels of unemployment.
The increase in maternal obesity has serious implications for the health of mothers, infants and service providers, yielding an additional 47 500 women per year requiring high dependency care in England. The demography of women most at risk of first trimester obesity highlights health inequalities associated with maternal obesity, which urgently needs to be addressed.
Data from The Society of Thoracic Surgeons Adult Cardiac Surgery Database were analyzed to identify trends in patient characteristics and outcomes of mitral valve operations in North America.
All ...patients with isolated primary mitral valve operations with or without tricuspid valve repair, surgical atrial fibrillation ablation, or atrial septal defect closure performed July 2011 to September 2016 were identified. A subgroup analysis assessed patients with degenerative leaflet prolapse (DLP).
Isolated primary mitral valve operations were performed on 87,214 patients at 1,125 centers, increasing by 24% between 2011 (n = 14,442) and 2016 (n = 17,907). The most common etiology was DLP (60.7%); 4.3% had functional mitral regurgitation. Preoperatively, 47.3% of patients had an ejection fraction less than 60% and 34.2% had atrial fibrillation. Overall mitral valve repair rate was 65.6%, declining from 67.1% (2011) to 63.2% (2016; p < 0.0001). Repair rates were related to etiology (DLP, 82.5%; rheumatic, 17.5%). Of the 29,970 mitral valve replacements, 16.2% were preceded by an attempted repair. Repair techniques included prosthetic annuloplasty (94.3%), leaflet resection (46.5%), and artificial cord implantation (22.7%). Bioprosthetic valves were implanted with increasing frequency (2011, 65.4%; 2016, 75.8%; p < 0.0001). Less-invasive operations were performed in 23.0% and concomitant tricuspid valve repair in 15.7%. Unadjusted operative mortality was 3.7% (replacements) and 1.1% (repairs).
Patients undergoing primary isolated mitral valve operations commonly have ventricular dysfunction, atrial fibrillation, and heart failure. Although contemporary outcomes are excellent, earlier guideline-directed referral and increased frequency and quality of repair may further improve results of mitral valve operations.
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