714 research outputs found

    Parmsurv: a SAS Macro for Flexible Parametric Survival Analysis with Long-Term Predictions

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    Health economic evaluations often require predictions of survival rates beyond the follow-up period. Parametric survival models can be more convenient for economic modelling than the Cox model. The generalized gamma (GG) and generalized F (GF) distributions are extensive families that contain almost all commonly used distributions with various hazard shapes and arbitrary complexity. In this study, we present a new SAS macro for implementing a wide variety of flexible parametric models including the GG and GF distributions and their special cases, as well as the Gompertz distribution. Proper custom distributions are also supported. Different from existing SAS procedures, this macro not only supports regression on the location parameter but also on ancillary parameters, which greatly increases model flexibility. In addition, the SAS macro supports weighted regression, stratified regression and robust inference. This study demonstrates with several examples how the SAS macro can be used for flexible survival modeling and extrapolation.Comment: 15 pages, 1 figure, 10 tables, accepted by The Clinical Data Science Conference - PHUSE US Connect 202

    The American Board of Thoracic Surgery: Update

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    Perceptions of Adolescent Pregnancy Among Teenage Girls in Rakai, Uganda.

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    The leading causes of death and disability among Ugandan female adolescents aged 15 to 19 years are pregnancy complications, unsafe abortions, and childbirth. Despite these statistics, our understanding of how girls perceive adolescent pregnancy is limited. This qualitative study explored the social and contextual factors shaping the perceptions of adolescent pregnancy and childbirth among a sample of 12 currently pregnant and 14 never pregnant girls living in the rural Rakai District of Uganda. Interviews were conducted to elicit perceived risk factors for pregnancy, associated community attitudes, and personal opinions on adolescent pregnancy. Findings indicate that notions of adolescent pregnancy are primarily influenced by perceptions of control over getting pregnant and readiness for childbearing. Premarital pregnancy was perceived as negative whereas postmarital pregnancy was regarded as positive. Greater understanding of the individual and contextual factors influencing perceptions can aid in development of salient, culturally appropriate policies and programs to mitigate unintended adolescent pregnancies

    Corpus Refactoring: a Feasibility Study

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    © 2007 Johnson et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

    Totally endoscopic robot-assisted transmyocardial revascularization

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    ObjectiveLaser transmyocardial revascularization is an emerging therapy for intractable angina stemming from diffuse, small-vessel coronary disease not amenable to percutaneous coronary intervention or coronary bypass grafting. Presently, this therapy is delivered through a median sternotomy or left thoracotomy. In this pilot study, we sought to combine the advantages of a dexterous robotic surgical platform with a flexible fiberoptic laser to develop a minimally invasive approach toward transmyocardial revascularization.MethodsA flexible fiberoptic holmium:yttrium-aluminum-garnet laser probe (CardioGenesis Corporation, Foothill Ranch, Calif), deployed with the da Vinci surgical robotic system (Intuitive Surgical, Sunnyvale, Calif), was used to create transmyocardial channels through all left ventricular wall regions in 5 canine subjects. The channels were localized, quantified, and histologically analyzed to assess distribution, dimensions, and transmurality.ResultsTransmyocardial channels were successfully created in all 6 defined left ventricular wall segments by using this minimally invasive approach without port repositioning, instrument exchange, or probe modifications. Gross pathologic and histologic analyses confirmed the uniform distribution of 1.0-mm transmural channels in all left ventricular regions. No direct pressure, topical hemostatic agents, or suture repairs were required for hemostasis. No significant hemodynamic instability or sustained arrhythmias were encountered at any time during the procedures.ConclusionsWe report the first use of a prototype flexible fiberoptic laser probe deployed by the da Vinci surgical robotic system to successfully perform totally endoscopic off-pump transmyocardial revascularization in a canine model, demonstrating the feasibility, precision, and safety of this approach. Refinement of this minimally invasive technique may reduce the morbidity of open-chest transmyocardial revascularization and facilitate its use as sole therapy or as an adjunct to percutaneous coronary interventions
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