ANUARIO 2012: CIRUGÍA CARDÍACA EN ADULTOS. LAS REVISTAS DE LAS SOCIEDADES NACIONALES PRESENTAN UNA SELECCIÓN DE LAS INVESTIGACIONES QUE HAN IMPULSADO AVANCES RECIENTES EN CARDIOLOGÍA CLÍNICA / Almanac 2012: Adult cardiac surgery. The National Society Journals present selected research that has driven recent advances in Clinical Cardiology

Resumen Esta revisión abarca las más importantes publicaciones sobre cirugía cardíaca en adultos en los últimos años, incluida la base de la evidencia actual para la revascularización quirúrgica y el uso de la cirugía sin circulación extracorpórea, las arterias mamarias internas bilaterales y la extracción endoscópica de la vena. Se describen los cambios en la cirugía convencional de la válvula aórtica junto a los resultados de los ensayos clínicos y los registros para la implantación de válvula aórtica transcatéter, así como la introducción de métodos novedosos y menos cruentos de la cirugía convencional de reemplazo valvular aórtico. Se considera también la cirugía para la valvulopatía mitral, con énfasis en la cirugía para la insuficiencia mitral degenerativa asintomática. / Abstract This review covers the important publications in adult cardiac surgery in the last few years, including the current evidence base for surgical revascularisation and the use of off-pump surgery, bilateral internal mammary arteries and endoscopic vein harvesting. The changes in conventional aortic valve surgery are described alongside the outcomes of clinical trials and registries for transcatheter aortic valve implantation, and the introduction of less invasive and novel approaches of conventional aortic valve replacement surgery. Surgery for mitral valve disease is also considered, with particular reference to surgery for asymptomatic degenerative mitral regurgitation

Almanac 2012: adult cardiac surgery. The national society journals present selected research that has driven recent advances in clinical cardiology.

U ovom preglednom članku obrađujemo važne publikacije iz područja kardijalne kirurgije odraslih objavljene u zadnjih nekoliko godina, uključujući i trenutne dokaze o kirurškoj revaskularizaciji i primjeni kirurgije bez uporabe stroja za izvantjelesni krvotok, lijevoj i desnoj unutarnjoj grudnoj arteriji i endoskopskoj metodi vađenja vene. Promjene tradicionalne kirurgije aortne valvule su opisane zajedno sa ishodima kliničkih ispitivanja i registrima za transkatetersku implantaciju aortne valvule te uvođenjem manje invazivnih i novih pristupa tradicionalne kirurgije zamjene aortne valvule. Kirurgija bolesti mitralne valvule se također razmatra uz posebni osvrt na kirurgiju asimptomatske degenerativne mitralne regurgitacije.This review covers the important publications in adult cardiac surgery in the last few years, including the current evidence base for surgical revascularisation and the use of off-pump surgery, bilateral internal mammary arteries and endoscopic vein harvesting. The changes in conventional aortic valve surgery are described alongside the outcomes of clinical trials and registries for transcatheter aortic valve implantation, and the introduction of less invasive and novel approaches of conventional aortic valve replacement surgery. Surgery for mitral valve disease is also considered, with particular reference to surgery for asymptomatic degenerative mitral regurgitation

Monitoring performance of cardiac surgery: the SCTS governance programme

OBJECTIVES The SCTS have published mortality rates for cardiac surgery by named hospital since 2001 and by named surgeon since 2005. This clinical governance programme has been associated with improved mortality outcomes despite increasing numbers of high-risk patients undergoing surgery. We describe the process of analysing the 2008-11 in-hospital mortality data, including the management, data processing and statistical framework. METHODS All SCTS data from April-2008 to March-2011 were extracted from the central cardiac audit database. The data were cleaned and summaries, including missing data, returned to units for validation. Afterwards, the final extract was cleaned and procedures classed as emergency, salvage, transplantation, trauma or primary-VAD removed. The primary outcome was in-hospital mortality. A contemporary recalibration of the logistic EuroSCORE model was developed for risk-adjustment. Funnel plots were used to detect outlier units with 95% and 99% two-sided confidence limits. One-sided 95% confidence limits corrected for multiple comparisons and multiplicative adjustment for overdispersion are examined. RESULTS A total of 106,982 records were included from 40 hospitals and 301 consultants. The mean mortality was 2.7% in all cardiac surgery. The recalibrated model was well calibrated (Hosmer-Lemeshow test P=0.56) and had good discrimination (AUC=0.78). Funnel plots were generated for each procedure group comparing 1) hospitals and 2) consultants. CONCLUSIONS The detection of ‘outlier’ healthcare providers is a challenging exercise and requires careful planning and analysis. By combing clinical and statistical expertise with robust methodology, we can reduce the chances of falsely classifying a unit as an ‘outlier’

Ultradian rhythms in glucose regulation: A mathematical assessment

Glucose regulation is an essential function of the human body which enables energy to be effectively utilized by the brain, organs and muscles. This regulation operates in a cyclic manner, in different periodic regimes. Indeed, ultradian rhythms with a period of 70 to 150 minutes have been clinically observed in healthy patients under various glucose stimulation patterns. Various models of these oscillations in plasma glucose and insulin have shown that the presence of two delays in hepatic glycogenesis and pancreatic insulin secretion provide a pathway for explaining these oscillations. The efficacy of this control is typically reduced in the presence of diabetes. In this contribution, we adopt the presence and the accurate tuning of ultradian rhythms as a criterion for healthy glucose regulation. We then investigate a model with two delays of these ultradian rhythms which incorporates parameters accounting for insulin sensitivity and insulin secretion. Additionally, the effect of diabetic deficiencies on this feedback loop is explored by quantifying the joint contribution of delays and diabetic parameters on the limit cycle of this model, which is generated through a Hopf bifurcation. Strategies for restoring an oscillatory regime in a physiologically appropriate range are discussed. Finally, a simple polynomial model of the oscillations is introduced to give further insight into the influence of each physiological subsystem. The approach provides a quantified relationship between diabetic impairments and the plasma glucose-insulin feedback loop

Reusing routinely collected clinical data for medical device surveillance

Background Following the public healthcare scandal surrounding Poly Implant Prothèse breast implants, there is increased focus on the surveillance of medical devices. A number of clinical specialties in the UK prospectively collect clinical data on procedures performed. We explore a surveillance programme in the case study of prosthetic aortic valve heart implants, reusing routinely collected data. Methods Demographic, comorbidity and operative pseudonymised data from the UK National Adult Cardiac Surgery Audit registry were extracted for all patients undergoing an aortic valve replacement (AVR) operation from 1998-onwards. Rules were developed to classify implants, recorded as free-text, by manufacturer, series, model and prosthesis type, and cleaning algorithms applied to the dataset. Patient outcomes are assessed across implants. Long-term mortality follow-up was tracked by record linkage to the Office for National Statistics death register, and surgical re-intervention tracked by reoccurrence in the registry. Results Data on 95,000 AVR operations were extracted. Prosthetic implants were classified into 97 models from ten manufacturers. There were substantial differences in implant volumes by manufacturers, deconstructed into temporal trends, prosthesis type and models, and healthcare providers. Significant differences were observed in outcomes between models. These differences are influenced by case-mix selection bias. Conclusion Reuse of routinely collected clinical data for medical device surveillance is viable and economically effective. Data collected, when properly analysed, can potentially be used to detect inferior devices, inform manufacturers and clinicians of device quality, supplement research, facilitate development of (inter-) national clinical guidelines for implant choice and inform businesses and healthcare procurement officers about market access. Linkage to other routinely collected data, including Hospital Episode Statistics, product data and other audits, offer richer surveillance capabilities

The UK Heart Valve Registry web-tool

Introduction The UK Heart Valve Registry (Taylor, 1997) was established in 1986, but funding was withdrawn for this project in 2004. The SCTS has collected implant data through the National Adult Cardiac Surgery Audit (NACSA) registry. An interactive web tool is developed that allows users to analyse trends and long- term survival by prosthesis manufacturer, model, valve, and time period. Materials and Methods In addition to clinical data collected in the NACSA registry, valve name and model data is also recorded. However, this data is in free-text format. An algorithm is developed to map each AVR record to brand and model. An interactive web tool is developed using R-Studio Shiny. Trends are shown using Google Charts. A reactive Kaplan-Meier plot allows for survival curve display and comparison using record linkage to the ONS database. Results The tool currently exists for the aortic valve. There were >8000 different entries in the database, which mapped to ~100 valves. Missing data or completely unmatchable valves account for ~17% of the data. In total there is data on >87,000 AVR implants. The web tool allows access to a number of interesting trends about the implantation rates, market share dynamics and survival data. We will demonstrate the app live at the meeting presentation. Discussion Following the PPI breast implant saga, there has been an increased focus on the monitoring of medical devices. There are a range of prostheses and sub- prostheses, with novel technology emerging. It is important to be able to track and monitor these prostheses. This web tool, which is still in development, begins to address these issues. In time this tool will be expanded to cover other valves and repair devices. Conclusion The UK Heart Valve Registry was disbanded a decade ago, leaving a large gap in the knowledge of the valve market and outcomes. Using routinely collected data and modern web app development tools, we can explore this data. References Taylor K. The United Kingdom Heart Valve Registry: the first 10 years. Heart. 1997 April; 77(4): 295–296

Unlocking a national adult cardiac surgery audit registry with R

Following the Bristol Royal Infirmary heart scandal, the Society of Cardiothoracic Surgery in Great Britain & Ireland (SCTS) established a world-leading clinical registry to collect data on all adult cardiac surgery procedures. To date this registry contains >480,000 records and 163 fields. The data includes patient demographics, comorbidities and clinical measurements, cardiac and operative details, and post-operative outcomes. We will describe examples of how R has been used recently to interrogate the SCTS registry and run a national governance programme for performance monitoring. Understanding the data is vital to making decisions. The SCTS have recently used the googleVis package by Gesmann and de Castillo (2011) to visualize hospital- and surgeon-level data longitudinally over time as Google Motion Charts (SCTS, 2013a). This can be used to interrogate, for example, the risk-adjusted mortality rate of healthcare providers, whilst gaining an understanding of the variation due to sample size or inherent natural variability. It can also be used to understand the multivariate relationships between data; for example is postoperative length-of-stay related to patient age and the number of operations performed by each hospital? This tool has already been the instigator of a number of clinical and care-quality investigations. Monitoring performance of surgeons requires a broad portfolio of tools. First, statistical modelling tools, for example glm or glmer, are required to appropriately ‘risk-adjust’ outcomes. Second, functions to aggregate and summarize the data in different ways over healthcare providers are required. Finally, graphical tools are required to present the results as funnel plots and case mix charts to patients for scrutiny of their healthcare provision (SCTS 2013b). “Real-world” databases are messy – the SCTS registry is no exception. Cleaning data can be complicated, especially if there interdependencies between data frame rows and columns. Synonyms and homonyms required homogenizing; numerical, temporal and clinical conflicts required resolving; and duplicate records required accurate identification and removal. Previously this was a terminal obstacle facing cardiac surgeons in their bid to unlock the potential of this data. A registry-specific R package has been written to fully automate the cleaning in a transparent and reproducible manner, thus enabling analyses of the data. References Gesmann M and de Castillo D (2011). googleVis: Interface between R and the Google Visualisation API. The R Journal 3, 40-44. SCTS (2013a). Dynamic charts, http://www.scts.org/DynamicCharts. SCTS (2013b). Performance reports, http://www.scts.org/patients/default.aspx