Basal cusp enlargement for repair of aortic valve insufficiency

ObjectiveThe aim of this study was to evaluate the clinical and echocardiographic results after aortic valve reconstruction with a novel surgical technique consisting of basal cusp enlargement with an autologous pericardial patch.MethodsBetween December 2005 and June 2008, a total of 106 consecutive patients underwent elective valve-sparing aortic root repair at Cardiovascular Clinic, Bad Neustadt, Germany. Fifty-nine patients required additional procedures on the aortic cusps; among them, in 10 cases basal cusp enlargement was used for restoration of coaptation area. All these patients had an ascending aortic aneurysm combined with aortic insufficiency, which was severe (4+) in 2 cases and moderate to severe (3+) in 4. The root repair was performed with valve reimplantation (David technique) in 1 case and the author's own single-patch technique in the other 9. Partial and total arch replacements were performed in 3 and 1 cases, respectively.ResultsThe postoperative echocardiography at discharge showed no aortic regurgitation in 7 cases and trivial regurgitation in 3. The average coaptation height of the leaflets was 9.9 ± 0.6 mm, and the mean gradient across the valve was 5.4 ± 1.9 mm Hg. At follow-up as late as 31 months, all patients were alive with echocardiographic findings unchanged from the early postoperative examinations.ConclusionsThe technique presented here allows an individualized reconstruction of the aortic cusps, leading to considerable improvement in coaptation area, in patients who have aortic leaflet prolapse or restriction caused by complex aortic root and valve disease

Evidence-Based Cardiac Monitoring: A Practice Change

Background: Overuse of cardiac monitoring (CM) in acute care settings contributes to increased healthcare spending and cost of services for patients. Additionally, inappropriate use of CM can contribute to wastefulness of healthcare resources, increases in hospital staff workloads, and can be improved with best evidence-based practice recommendations. A Midwest acute care hospital lacked an evidence-based, systematic method to define care for patients requiring CM. Objective: The purpose of the project was to pilot an evidence-based CM change initiative, determine feasibility for sustainment, and propose next steps for adoption of the change initiative across non-emergency department, non-intensive care inpatient CM units at a Midwest, acute care hospital. Method: The project involved piloting an evidence-based practice change that focused on the appropriate use of CM. The practice change consisted of education for ordering providers and nurses on the current American Heart Association\u27s (AHA) and American College of Cardiology\u27s (ACC) CM guidelines (2017), nurse/provider communication, and utilization of a CM clinical tool in daily practice. Data was collected regarding appropriate CM orders, duration of time patients were maintained on CM, and the number of patients maintained on CM until discharge from the hospital over a two-week pre-implementation period and a six-week post-implementation period for comparison. The results of the study were then used to develop evidence-based recommendations for implementing a hospital-wide, CM practice change. Results: There was a significant decrease in the number of inappropriate CM orders over the duration of the project. Inappropriate CM orders were reduced from 35.0% to 12.1% (p = 0.0019). Additionally, there was a significant decrease in the number of patients maintained on monitoring until the time of discharge, 95.0% to 66.7% (p = 0.0121). The approximate cost savings for delivering CM services to patients over the duration of the project was $11,222.40 and$97,528.00 over a year. Estimated cost of services included patient monitoring, CM equipment, and upkeep of equipment. Approximate cost savings for RN wages over the duration of the project was $2,394.00 and$20,805.00 over a year. Conclusions: Implementation of an evidence-based practice change significantly decreased the number of inappropriate CM orders as well as the number of patients maintained on CM at the time of discharge from the hospital. Recommendations for sustainability of the practice change include incorporating the use of the AHA/ACC\u27s CM guideline in the electronic ordering system (EOS), use of evidence-based CM guidelines in daily practice, discussion of CM in daily interdisciplinary rounds, continued education for staff on AHA/ACC CM guidelines, and utilization of unit charge nurses to replicate the pilot study findings throughout the organization

Application of microfluidic emulsion technology to biochemistry, drug delivery and Lab-on-a-Chip programmability

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 129-138).This research applies microfluidic emulsion technology to three diverse problems; biochemistry, drug delivery and lab-on-a-chip programmability. These subjects represent distinct research programs, but the underlying physics of droplet formation, transport and control at low values of the Reynolds and Capillary numbers in multiphase microfluidics allows them to be considered in parallel and supports the flexibility of this technology. Within these stamp-sized elastomeric polydimethylsiloxane (PDMS) microfluidic devices, pressurized immiscible fluids may be combined at a junction of two or more microchannels, combining crossflow and viscoelastic shear, to generate emulsions. Droplet sizes may be tuned from nanometers to microns in diameter, controlled by device geometry and hydrodynamic flow characteristics. The application of droplets as individual bioreactors for biochemical assays is first explored at the device and external sensor level. The goal of this research is to extend on existing approaches and address challenges of platform scalability. Microchannel design strategies are analyzed then fabricated in order to increase sample incubation periods. Using monodisperse droplet formation within microfluidic devices, techniques are developed for the manufacture of drug loaded biodegradable polymeric particles for controlled release of encapsulated ingredients within biological systems. Coupled with the bulk method of solvent evaporation, microspheres with a tunable range of volumes spanning four orders of magnitude are generated and characterized using this rapid and flexible prototyping technique. Finally, a programmable microfluidic system platform using multiphase flows in soft lithography is developed.(cont.) To demonstrate scalability of this approach, a "general- purpose" microfluidic chip is implemented, where underlying mechanisms for sample manipulation can be integrated to develop more complex systems. This research represents a first step to bring high-level control abstractions to the microfluidic realm, with the aim of enabling a new level of scalability and programmability for lab-on-a-chip experiments.by John Paul Urbanski.S.M

Microfluidic tools for metabolomics

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 153-160).A primary challenge in embryology is to understand the factors that govern the development of preimplantation (PI) embryos and how these factors relate to embryo viability in the field of in vitro fertilization (IVF). This is particularly important as clinical policy moving towards single embryo transfer (SET) has gained awareness to manage unprecedented numbers of multiple births, such as twins and triplets, resulting from artificial reproductive techniques. Conditions that correlate with developmental potential of candidate embryos are disputed in the field, however, as the requisite data is difficult to obtain.The metabolic profiles of embryos during in vitro culture have been suggested as a key indicator of developmental potential, and approaches have been clinically implemented to select transfer candidates which make the most efficient use of nutrients. Existing microdroplet analysis techniques are accurate and suitable for non-invasive assessment of single embryos. Unfortunately, the process of determining metabolite levels in nanoliters of culture media through fluorometric assays is low-throughput and requires specialized expertise, hindering widespread clinical use of these methods. The goal of this thesis is to develop microfluidics-based approaches for improving metabolic analysis of PI embryos and mammalian cells. This challenge necessitates two competencies: methods for automating chemical assays and methods for supporting cell cultures, which can be integrated with analysis. Contributions include a standalone platform for determining the metabolite use of single embryos. Profiles may be acquired automatically, which reduces significant technician hours and improves repeatability. Techniques are developed for performing embryo culture in the smallest culture volumes to date in microfabricated environments. Microfluidic approaches have enabled culture that outperforms the current state of art approach based on cell count measurements.(cont.) An integrated system is introduced, merging analysis and culture competencies to perform metabolic profiling of separate cultures of mammalian cells in parallel. Finally, new paradigms in microfluidic design are presented based on the concept of vertically integrated architectures, suitable for overcoming density limitations of microfluidic assays. A scalable analysis platform for refining embryo selection has been long warranted and would enable pursuit of the difficult questions relating metabolism and embryo viability as the clinical movement towards SET continues.by John Paul Urbanski.Ph.D

Abstraction Layers for Scalable Microfluidic Biocomputers (Extended Version)

Microfluidic devices are emerging as an attractive technology for automatically orchestrating the reactions needed in a biological computer. Thousands of microfluidic primitives have already been integrated on a single chip, and recent trends indicate that the hardware complexity is increasing at rates comparable to Moore's Law. As in the case of silicon, it will be critical to develop abstraction layers--such as programming languages and Instruction Set Architectures (ISAs)--that decouple software development from changes in the underlying device technology.Towards this end, this paper presents BioStream, a portable language for describing biology protocols, and the Fluidic ISA, a stable interface for microfluidic chip designers. A novel algorithm translates microfluidic mixing operations from the BioStream layer to the Fluidic ISA. To demonstrate the benefits of these abstraction layers, we build two microfluidic chips that can both execute BioStream code despite significant differences at the device level. We consider this to be an important step towards building scalable biocomputers

The association between celiac disease and eosinophilic esophagitis in children and adults

BACKGROUND: An association between eosinophilic esophagitis (EoE) and celiac disease (CD) has been suggested in the literature. Our aim was to confirm and quantify the association between these two diseases. METHODS: All patients in a large Canadian city diagnosed with EoE or CD over a five-year period were identified. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated. RESULTS: Over the five-year study EoE was diagnosed in 421 patients and CD was diagnosed in 763 patients. The incidence of EoE ranged from 2.1 to 10.7 cases per 100,000 population. The incidence of CD ranged from 10.4 to 15.7 cases per 100,000 population. Among the EoE cohort, 83 (20%) cases of EoE and 245 (32%) cases of CD were diagnosed in pediatric patients. The incidence of EoE in the pediatric subpopulation ranged from 3.7 to 6.9 cases per 100,000 population. The incidence of CD in the pediatric subpopulation ranged from 9.5 to 22.7 cases per 100,000 population. The concomitant diagnosis of both EoE and CD was made in three patients, all of whom were pediatric males. The SIR for EoE in the CD cohort was 48.4 (95% CI = 9.73, 141.41) with a SIR for CD within the paediatric EoE cohort of 75.05 (95% CI = 15.08, 219.28). CONCLUSIONS: This study confirms the association between EoE and CD. However, this association may be limited to pediatrics where the risk of each condition is increased 50 to 75-fold in patients diagnosed with the alternative condition. The concomitant diagnosis of these conditions should be considered in pediatric patients with upper gastrointestinal symptoms

Use of matrix-assisted laser desorption ionization-time of flight mass spectrometry to identify vancomycin-resistant enterococci and investigate the epidemiology of an outbreak

The control of vancomycin-resistant enterococci (VRE) has become an increasing burden on health care resources since their discovery over 20 years ago. Current techniques employed for their detection include time-consuming and laborious phenotypic methods or molecular methods requiring costly equipment and consumables and highly trained staff. An accurate, rapid diagnostic test has the ability to greatly reduce the spread of this organism, which has the ability to colonize patients for long periods, potentially even lifelong. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a technology with the ability to identify organisms in seconds and has shown promise in the identification of other forms of antimicrobial resistance in other organisms. Here we show that MALDI-TOF MS is capable of rapidly and accurately identifying vanB-positive Enterococcus faecium VRE from susceptible isolates. Internal validation of the optimal model generated produced a sensitivity of 92.4% and a specificity of 85.2%. Prospective validation results, following incorporation into the routine laboratory work flow, demonstrated a greater sensitivity and specificity at 96.7% and 98.1%, respectively. In addition, the utilization of MALDI-TOF MS to determine the relatedness of isolates contributing to an outbreak is also demonstrated

Current status and recommendations for use of the frozen elephant trunk technique: a position paper by the Vascular Domain of EACTS†

The implementation of new surgical techniques offers chances but carries risks. Usually, several years pass before a critical appraisal and a balanced opinion of a new treatment method are available and rely on the evidence from the literature and expert's opinion. The frozen elephant trunk (FET) technique has been increasingly used to treat complex pathologies of the aortic arch and the descending aorta, but there still is an ongoing discussion within the surgical community about the optimal indications. This paper represents a common effort of the Vascular Domain of EACTS together with several surgeons with particular expertise in aortic surgery, and summarizes the current knowledge and the state of the art about the FET technique. The majority of the information about the FET technique has been extracted from 97 focused publications already available in the PubMed database (cohort studies, case reports, reviews, small series, meta-analyses and best evidence topics) published in Englis

Multicentre analysis of current strategies and outcomes in open aortic arch surgery: heterogeneity is still an issue

Abstract OBJECTIVES: The study was conducted to evaluate, on the basis of a multicentre analysis, current results of elective open aortic arch surgery performed during the last decade. METHODS: Data of 1232 consecutive patients who underwent aortic arch repair with reimplantation of at least one supra-aortic artery between 2004 and 2013 were collected from 11 European cardiovascular centres, and retrospective statistical examination was performed using uni-and multi-variable analyses to identify predictors for 30-day mortality. Acute aortic dissections and arch surgeries not involving the supra-aortic arteries were not included. RESULTS: Arch repair involving all 3 arch arteries (total), 2 arch arteries (subtotal) or 1 arch artery ( partial) was performed in 956 (77.6%), 155 (12.6%) and 121 (9.8%) patients, respectively. The patients' characteristics as well as the surgical techniques, including the method of cannulation, perfusion and protection, varied considerably between the clinics participating in the study. The in-hospital and 30-day mortality rates were 11.4 and 8.8% for the entire cohort, respectively, ranging between 1.7 and 19.0% in the surgical centres. Multivariable logistic regression analysis identified surgical centre, patient's age, number of previous surgeries with sternotomy and concomitant surgeries as independent risk factors of 30-day mortality. The follow-up of the study group was 96.5% complete with an overall follow-up duration of 3.3 ± 2.9 years, resulting in 4020 patient-years. After hospital discharge, 176 (14.3%) patients died, yielding an overall mortality rate of 25.6%. The actuarial survival after 5 and 8 years was 72.0 ± 1.5% and 64.0 ± 2.0, respectively. CONCLUSIONS: The surgical risk in elective aortic arch surgery has remained high during the last decade despite the advance in surgical techniques. However, the patients' characteristics, numbers of surgeries, the techniques and the results varied considerably among the centres. The incompleteness of data gathered retrospectively was not effective enough to determine advantages of particular cannulation, perfusion, protection or surgical techniques; and therefore, we strongly recommend further prospective multicentre studies, preferably registries, in which all relevant data have to be clearly defined and collected