24 research outputs found

    Homograft use in reoperative aortic root and proximal aortic surgery for endocarditis: A 12-year experience in high-risk patients

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    ObjectivesWe examined the early and midterm outcomes of homograft use in reoperative aortic root and proximal aortic surgery for endocarditis and estimated the associated risk of postoperative reinfection.MethodsFrom January 2001 to January 2014, 355 consecutive patients underwent reoperation of the proximal thoracic aorta. Thirty-nine patients (10.9%; mean age, 55.4 ± 13.3 years) presented with active endocarditis; 30 (76.9%) had prosthetic aortic root infection with or without concomitant ascending and arch graft infection, and 9 (23.1%) had proximal ascending aortic graft infection with or without aortic valve involvement. Sixteen patients (41.0%) had genetically triggered thoracic aortic disease. Twelve patients (30.8%) had more than 1 prior sternotomy (mean, 2.4 ± 0.6).ResultsValved homografts were used to replace the aortic root in 29 patients (74.4%); nonvalved homografts were used to replace the ascending aorta in 10 patients (25.6%). Twenty-five patients (64.1%) required concomitant proximal arch replacement with a homograft, and 2 patients (5.1%) required a total arch homograft. Median cardiopulmonary bypass, cardiac ischemia, and circulatory arrest times were 186 (137-253) minutes, 113 (59-151) minutes, and 28 (16-81) minutes. Operative mortality was 10.3% (n = 4). The rate of permanent stroke was 2.6% (n = 1); 3 additional patients had transient neurologic events. One patient (1/35, 2.9%) returned with aortic valve stenosis 10 years after the homograft operation. During the follow-up period (median, 2.5 years; range, 1 month to 12.3 years), no reinfection was reported, and survival was 65.7%.ConclusionsThis is one of the largest North American single-center series of homograft use in reoperations on the proximal thoracic aorta to treat active endocarditis. In this high-risk population, homograft tissue can be used with acceptable early and midterm survival and a low risk of reinfection. When necessary, homograft tissue may be extended into the distal ascending and transverse aortic arch, with excellent results. These patients require long-term surveillance for both infection and implant durability

    Surgical intervention for infective endocarditis in a veteran population

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    Abstract BACKGROUND: Surgical management of infective endocarditis can be challenging. Veteran patients are unique because they often have significant comorbidities, and surgical management of endocarditis in this population has not been well described. METHODS: Using a prospective database, 46 consecutive patients who underwent valve surgery for acute infective endocarditis between 1987 and 2009 were identified. Survival was assessed using the Kaplan-Meier method. RESULTS: All patients were men (mean age, 56±9 years). The most common indication for surgical intervention was congestive heart failure (60%). The aortic valve was the only valve infected in most patients (65%). Operative morbidity and mortality were 33% and 9%, respectively. The 1-year, 3-year, 5-year, and 10-year unadjusted survival rates were 72%, 57%, 51%, and 30%, respectively. CONCLUSIONS: Although acceptable short-term outcomes can be achieved in veterans undergoing surgical treatment for endocarditis, unadjusted long-term survival may be poor

    Nationwide trends and regional/hospital variations in open versus endovascular repair of thoracoabdominal aortic aneurysms

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    ObjectivesThoracic endovascular aortic repair (TEVAR) has been gaining popularity for the treatment of thoracoabdominal aortic aneurysm (TAAA). We used a nonvoluntary database to examine national trends and regional/hospital variations in the use of TEVAR and open thoracic aortic repair (OTAR) for TAAA.MethodsFrom the 2005-2008 Nationwide Inpatient Sample database, we identified all patients with the diagnosis of TAAA who were treated with TEVAR or OTAR. Rates of these procedures were compared between years, across geographic regions, and between hospitals of various bed sizes.ResultsOver the study period, the rate of OTAR remained relatively stable (range, 7.5/100 patients in 2005 to 10.1/100 patients in 2008; P = .26), whereas the rate of TEVAR increased dramatically (range, 1.4/100 patients in 2005 to 6.3/100 patients in 2008; P < .0001). In 2008, 29% (211) of all TEVAR procedures and 11% (130) of all OTAR procedures were performed in western regions of the United States (P = .03). Additionally, 13% (95) of all TEVAR procedures and 3% (35) of all OTAR procedures were performed in smaller hospitals (P < .0001).ConclusionsThe use of TEVAR for TAAA repair increased significantly over the study period, whereas OTAR rates remained relatively stable. Our findings suggest that more patients who were otherwise not surgical candidates or did not have traditional surgical indications for OTAR were treated with TEVAR, most commonly in regions or hospitals where OTAR is less often performed. Given the complexity of TAAA cases, these results may have significant implications for patient safety in the current era of heightened health care scrutiny

    A Geographic Mosaic of Climate Change Impacts on Terrestrial Vegetation: Which Areas Are Most at Risk?

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    <div><p>Changes in climate projected for the 21<sup>st</sup> century are expected to trigger widespread and pervasive biotic impacts. Forecasting these changes and their implications for ecosystem services is a major research goal. Much of the research on biotic responses to climate change has focused on either projected shifts in individual species distributions or broad-scale changes in biome distributions. Here, we introduce a novel application of multinomial logistic regression as a powerful approach to model vegetation distributions and potential responses to 21<sup>st</sup> century climate change. We modeled the distribution of 22 major vegetation types, most defined by a single dominant woody species, across the San Francisco Bay Area. Predictor variables included climate and topographic variables. The novel aspect of our model is the output: a vector of relative probabilities for each vegetation type in each location within the study domain. The model was then projected for 54 future climate scenarios, spanning a representative range of temperature and precipitation projections from the CMIP3 and CMIP5 ensembles. We found that sensitivity of vegetation to climate change is highly heterogeneous across the region. Surprisingly, sensitivity to climate change is higher closer to the coast, on lower insolation, north-facing slopes and in areas of higher precipitation. While such sites may provide refugia for mesic and cool-adapted vegetation in the face of a warming climate, the model suggests they will still be highly dynamic and relatively sensitive to climate-driven vegetation transitions. The greater sensitivity of moist and low insolation sites is an unexpected outcome that challenges views on the location and stability of climate refugia. Projections provide a foundation for conservation planning and land management, and highlight the need for a greater understanding of the mechanisms and time scales of potential climate-driven vegetation transitions.</p></div

    Projected vegetation change at selected sites.

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    <p>Illustration of Bray-Curtis distances between baseline and future vegetation vectors (similar to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130629#pone.0130629.g003" target="_blank">Fig 3</a>) for two selected pixels across our model domain. The slope of this relationship was used as a measure of the sensitivity of projected vegetation change in relation to climate, with mean annual temperature as a proxy for changes in JJA, DJF, and CWD. Much of the scatter around each regression line represents additional effects of PPT. Red illustrates a site with high sensitivity (slope = 0.298) and blue a site with low sensitivity (slope = 0.104).</p

    Projected change in selected vegetation types.

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    <p>Changes in relative abundance of four vegetation types, plotted relative to mean annual temperature (MAT) of each of the climate scenarios. Colors indicate change in precipitation (see legend in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130629#pone.0130629.g004" target="_blank">Fig 4</a>). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130629#pone.0130629.s006" target="_blank">S6 Fig</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130629#pone.0130629.s014" target="_blank">S5 Table</a> for results for all 22 vegetation types.</p

    Historical and projected climate means.

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    <p>Thirty year climatic means vs. mean annual temperature for the historic (1951–1980, red) and recent (1981–2010, blue) periods and 54 possible futures (black) based on 18 different model/forcing scenarios and three time periods (2010–2039, 2040–2069, 2070–2099). See values in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130629#pone.0130629.s012" target="_blank">S3 Table</a>.</p
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