Valve-sparing aortic root reconstruction

The aortic valve-sparing reimplantation is a challenging procedure. Preservation of the native valve permits the maintenance of a proper hemodynamic and avoids the lifelong anticoagulation but the risk of recurrent aortic regurgitation remains its Achilles heel. The aim of this study is to evaluate the results of the aortic-valve sparing reimplantation technique presented both as single and multi -center experience. The impact of several variables on mortality and morbidity has been investigated. Moreover, the outcome of alternative techniques to treat the aortic root aneurysmal pathology, such as the Bentall and the Ross operation, has been explored. The following issues have been explored: - Early and mid-term results of the aortic valve reimplantation technique with reconstruction of the sinuses of Valsalva and compliance of the Valsalva graft pseudosinus at mid-term follow-up (Chapter 2-5). - Results of valve-sparing aortic root replacement in different settings including Marfan patients, bicuspid aortic valve and older patients (Chapter 6-8). - Impact of additional aortic cusp repair in patients with bicuspid and tricuspid aortic valve including long-term results (Chapter 9,10). - Outcome of the aortic root replacement with composite valve graft (Chapter 11,12). - Results of the Ross operation for the aortic root replacement (Chapter 13). Long-term results the aortic-valve sparing reimplantation show that this technique is extremely reliable, at least in presence of normal or nearly normal aortic cusps. Concerns regarding the durability of the aortic valve remain for patients who require extensive cusp repair. The composite valve graft procedure, according to the modified Bentall technique, is currently considered the gold standard for the treatment of the aortic root aneurysm or acute type I dissection in the presence of a irreparable aortic valve. The Ross operation represents an alternative treatment in young adults with non-reparable aortic valve with or without aortic root aneurysm

Data from: Evolution of sociality in spiders leads to depleted genomic diversity at both population and species level

Across several animal taxa, the evolution of sociality involves a suite of characteristics, a ‘social syndrome’, that includes cooperative breeding, reproductive skew, primary female biased sex-ratio, and the transition from outcrossing to inbreeding mating system, factors that are expected to reduce effective population size (Ne). This social syndrome may be favoured by short-term benefits but come with long-term costs, because the reduction in Ne amplifies loss of genetic diversity by genetic drift, ultimately restricting the potential of populations to respond to environmental change. To investigate the consequences of this social life form on genetic diversity, we used a comparative RAD-sequencing approach to estimate genome-wide diversity in spider species that differ in level of sociality, reproductive skew, and mating system. We analysed multiple populations of three independent sister-species pairs of social inbreeding and subsocial outcrossing Stegodyphus spiders, and a subsocial outgroup. Heterozygosity and within population diversity were 6-10 fold lower in social compared to subsocial species, and demographic modelling revealed a tenfold reduction in Ne of social populations. Species-wide genetic diversity depends on population divergence and the viability of genetic lineages. Population genomic patterns were consistent with high lineage turnover, which homogenizes the genetic structure that builds up between inbreeding populations, ultimately depleting genetic diversity at the species level. Indeed, species-wide genetic diversity of social species was 5-8 times lower than that of subsocial species. The repeated evolution of species with this social syndrome is associated with severe loss of genome-wide diversity, likely to limit their evolutionary potential

Prey to predator body size ratio in the evolution of cooperative hunting—a social spider test case

One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed ‘prey to predator size ratio hypothesis’ and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators

Diverging cooperative prey capture strategies in convergently evolved social spiders

Sociality in spiders has evolved independently multiple times, resulting in convergently evolved cooperative breeding and prey capture. In all social spiders, prey is captured by only a subset of group members and then shared with other, non-attacking group members. However, spiders' propensity to attack prey may differ among species due to species-specific trade-offs between risks, costs and benefits of prey capture involvement. We explored whether engagement in prey attack differs among three social Stegodyphus species, using orthopteran prey, and found substantial differences. Stegodyphus mimosarum Pavesi, 1883 had a low prey acceptance rate, was slow to attack prey, and engaged very few spiders in prey attack. In S. sarasinorum Karsch, 1892, prey acceptance was high, independently of prey size, but more spiders attacked when prey was small. While medium-sized prey had higher acceptance rate in S. dumicola Pocock, 1898, indicating a preference, the number of attackers was not affected by prey size. Our results suggest that the three species may have different cooperative prey capture strategies. In S. mimosarum and S. dumicola, whose geographical ranges overlap, these strategies may represent niche specialization, depending on whether their respective cautious and choosy approaches extend to other prey types than orthopterans, while S. sarasinorum may have a more opportunistic approach. We discuss factors that can affect social spiders' foraging strategy, such as prey availability, predation pressure, and efficiency of the communal web to ensnare prey. Future studies are required to investigate to which extent species-specific cooperative foraging strategies are shaped by ontogeny, group size, and plastic responses to environmental factors

Reimplantation valve-sparing aortic root replacement in Marfan syndrome using the Valsalva conduit: an intercontinental multicenter study.

BACKGROUND: Introduced by DePaulis in 2000, the Gelweave Valsalva graft (Sulzer Vascutek, Refrewshire, Scotland) is a modified Dacron conduit (DuPont, Wilmington, DE), with prefashioned sinuses of Valsalva. The aim of this study was to evaluate the mid-term results of the reimplantation valve-sparing aortic root replacement using the Gelweave Valsalva prosthesis in Marfan syndrome patients. METHODS: A retrospective review was performed of 35 patients with Marfan syndrome in four centers who underwent the reimplantation valve-sparing aortic root replacement using the Gelweave Valsalva prosthesis. RESULTS: The patients were predominantly men, with a mean age of 36.5 +/- 12.6 years (range, 14 to 62 years). Two patients presented with acute type A dissections and underwent emergent operations. Elective hemiarch reconstruction using hypothermic circulatory arrest was required in 11 patients. Aortic valve cusp repair was performed in 2 patients. There were no operative or hospital deaths, and no patients died during follow-up. The mean follow-up was 19 months (range, 1 to 60 months). Significant (>2+) aortic insufficiency (AI), requiring aortic valve replacement, developed in 3 patients during follow-up that requiring aortic valve replacement. The 5-year freedom from reoperation owing to structural valve deterioration was 88.9% +/- 8.1%. There were no episodes of clinically significant thromboembolism. CONCLUSIONS: Reimplantation valve-sparing aortic root replacement with the Gelweave Valsalva prosthesis in Marfan patients provides satisfactory mid-term results, thus encouraging further use of this type of repair. However, long-term results are needed in order to define the durability of this technique

Compliance of the valsalva graft's pseudosinuses at midterm follow-up with cardiovascular magnetic resonance

Background In previous studies, the Valsalva graft's compliance at the level of the Dacron pseudosinuses was found similar to that of normal sinuses shortly (2 \ub1 1 months) after the operation. We sought to investigate with cardiac magnetic resonance the compliance of the Valsalva graft pseudosinuses at midterm follow-up. Methods Seven patients (group A) and 7 age-matched controls (group B) were studied with steady-state free precession and phase-contrast cardiac magnetic resonance for aortic root and ascending aorta evaluation. Blood pressure was measured during phase-contrast acquisition to derive the following mechanical properties of the vascular prosthesis: pulsatility, compliance, distensibility, and elastic modulus. Results Mean postoperative follow-up was 55 \ub1 9.84 months. Mean age was 69.2 \ub1 4.98 years in group A, and 65.7 \ub1 7.16 years in group B. All the studied variables were coherent in showing a significant difference between the two groups, and between aortic root (skirt portion of the graft) and ascending aorta (tubular part of the graft) in group A. The presence of periaortic fibrosis did not show any correlation with the ascending aorta's mechanical properties. Conclusions At midterm follow-up, the pseudosinuses compliance of the Valsalva graft is still appreciable and significantly greater than the tubular portion

Early results of valve-sparing reimplantation procedure using the Valsalva conduit: a multicenter study.

BACKGROUND: This study evaluates the midterm clinical results of valve-preserving aortic root reconstruction by means of a modified conduit incorporating sinuses of Valsalva. METHODS: During a 5-year period, 151 patients with aneurysm of the aortic root underwent a reimplantation type of valve-sparing procedure using the Gelweave Valsalva prosthesis that incorporates sinuses of Valsalva. There were 121 males (80.1%), and the mean age was 56.4 +/- 14.4 years (range, 14 to 83). Fourteen percent of the patients had Marfan syndrome and 8.6% had bicuspid aortic valve. Seven patients (4.6%) suffered from acute aortic dissection. Aortic replacement was extended to the arch in 14 patients (9.3%). Sixteen patients (10.6%) had associated cusp repair. RESULTS: In-hospital mortality was 3.3%, and it was significantly higher among patients operated on for acute dissection (p = 0.001) and in symptomatic patients (III-IV New York Heart Association class; p = 0.021). Follow-up (mean, 18 months; range, 1 to 60) was 100% complete. There were 2 late deaths. Ten patients (6.8%) had 3 to 4+ aortic regurgitation, and 8 of these required late aortic valve replacement. Cusp repair was associated with a high incidence of late aortic valve replacement (p = 0.005). At 5 years, freedom from aortic valve replacement and freedom from grade 3 to 4 aortic insufficiency was 90.8% +/- 3.3% and 88.7% +/- 3.6%, respectively. CONCLUSIONS: The reimplantation valve-sparing procedure with the Gelweave Valsalva prosthesis provides satisfactory results for patients with aortic root aneurysm. Aortic cusp repair may lead to late aortic insufficiency. Proper leaflet evaluation is of paramount importance in preventing residual valve regurgitatio