Identifying cardiac surgery operations in hospital episode statistics administrative database, with an OPCS-based classification of procedures, validated against clinical data.

OBJECTIVES: Administrative databases with dedicated coding systems in healthcare systems where providers are funded based on services recorded have been shown to be useful for clinical research, although their reliability is still questioned. We devised a custom classification of procedures and algorithms based on OPCS, enabling us to identify open heart surgeries from the English administrative database, Hospital Episode Statistics, with the objective of comparing the incidence of cardiac procedures in administrative and clinical databases. DESIGN: A comparative study of the incidence of cardiac procedures in administrative and clinical databases. SETTING: Data from all National Health Service Trusts in England, performing cardiac surgery. PARTICIPANTS: Patients classified as having cardiac surgery across England between 2004 and 2015, using a combination of procedure codes, age >18 and consultant specialty, where the classification was validated against internal and external benchmarks. RESULTS: We identified a total of 296 426 cardiac surgery procedures, of which majority of the procedures were coronary artery bypass grafting (CABG), aortic valve replacement (AVR), mitral repair and aortic surgery. The matching at local level was 100% for CABG and transplant, >90% for aortic valve and major aortic procedures and >80% for mitral. At national level, results were similar for CABG (IQR 98.6%-104%), AVR (IQR 105%-118%) and mitral valve replacement (IQR 86.2%-111%). CONCLUSIONS: We set up a process which can identify cardiac surgeries in England from administrative data. This will lead to the development of a risk model to predict early and late postoperative mortality, useful for risk stratification, risk prediction, benchmarking and real-time monitoring. Once appropriately adjusted, the system can be applied to other specialties, proving especially useful in those areas where clinical databases are not fully established.

Clinical outcomes and costs of cardiac revascularisation in England and New York state.

Objectives: Healthcare expenditure per-capita in the USA is higher than in England. We hypothesised that clinical outcomes after cardiac revascularisation are better in the USA. We compared costs and outcomes of patients undergoing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in England and New York State (NYS). Methods: Costs and total mortality were assessed using the Hospital Episode Statistics for England and the Statewide Planning and Research Cooperative System for NYS. Outcomes after a first CABG or PCI were assessed in patients undergoing a first CABG (n=142 969) or PCI (n=431 416). Results: After CABG, crude total mortality in England was 0.72% lower at 30 days and 3.68% lower at 1 year (both P<0.001). After PCI, crude total mortality was 0.35% lower at 30 days and 3.55% lower at 1 year (both P<0.001). No differences emerged in total mortality at 30 days after either CABG (England: HR 1.02,95% CI 0.94 to 1.10) or PCI (HR 1.04, 95% CI 0.99 to 1.09) after covariate adjustment. At 1 year, adjusted total mortality was lower in England after both CABG (HR 0.74, 95% CI 0.71 to 0.78) and PCI (HR 0.66, 95% CI 0.65 to 0.68). After adjustment for cost-to-charge ratios and purchasing power parities, costs in NYS amounted to uplifts of 3.8-fold for CABG and 3.6-fold for PCI. Conclusions: Total mortality after CABG and PCI was similar at 30 days and lower in England at 1 year. Costs were approximately fourfold higher in NYS.

Long-term requirement for pacemaker implantation after cardiac valve replacement surgery.

BACKGROUND: The risk of permanent pacemaker implantation (PPI) after cardiac valve replacement surgery is thought to be highest in the postoperative period. Long-term risks are uncertain. OBJECTIVE: The purpose of this study was to determine rates and timing of PPI after cardiac valve replacement surgery. METHODS: We compared PPI rates of patients undergoing aortic valve replacement (AVR; n = 111,674), mitral valve replacement (MVR; n = 18,402), AVR + MVR (n = 5166), AVR + MVR + tricuspid valve replacement (TVR; n = 114), or coronary artery bypass surgery (CABG) without valve replacement (n = 249,742). RESULTS: Over a period of 14 years (median 3.9 years; interquartile range 1.1-7.4 years), cumulative PPI rates were 3.07-7.6 times higher (P < .001 for all) than after CABG, depending on the number of valves replaced. PPI risks after AVR were higher that those after MVR (hazard ratio [HR] 1.22; 95% confidence interval [CI] 1.16-1.28), AVR + MVR (HR 1.52; 95% CI 1.40-1.65), and AVR + MVR + TVR (HR 2.22; 95% CI 1.40-3.53), independent of known confounders. Cumulative PPI hazard rates from the postoperative period to 10 years after surgery increased after AVR (4.22%-14.4%), MVR (4.38%-15.6%), AVR + MVR (5.59%-18.3%), and AVR + MVR + TVR (7.89%-25.9%) (P < .001 for all). Age, male sex, emergency admission, and preexisting diabetes mellitus, renal impairment, and heart failure were independent predictors of PPI (P < .001 for all). CONCLUSION: Valve replacement surgery was associated with a long-term risk of PPI. This was particularly high after dual and triple valve replacements. Age, male sex, emergency admission, and preexisting diabetes mellitus, heart failure, and renal impairment were independent predictors of PPI.

Supercapattery Based on Binder-Free Co3(PO4)2·8H2O Multilayer Nano/Microflakes on Nickel Foam.

A binder-free cobalt phosphate hydrate (Co3(PO4)2·8H2O) multilayer nano/microflake structure is synthesized on nickel foam (NF) via a facile hydrothermal process. Four different concentrations (2.5, 5, 10, and 20 mM) of Co2+ and PO4-3 were used to obtain different mass loading of cobalt phosphate on the nickel foam. The Co3(PO4)2·8H2O modified NF electrode (2.5 mM) shows a maximum specific capacity of 868.3 C g-1 (capacitance of 1578.7 F g-1) at a current density of 5 mA cm-2 and remains as high as 566.3 C g-1 (1029.5 F g-1) at 50 mA cm-2 in 1 M NaOH. A supercapattery assembled using Co3(PO4)2·8H2O/NF as the positive electrode and activated carbon/NF as the negative electrode delivers a gravimetric capacitance of 111.2 F g-1 (volumetric capacitance of 4.44 F cm-3). Furthermore, the device offers a high specific energy of 29.29 Wh kg-1 (energy density of 1.17 mWh cm-3) and a specific power of 4687 W kg-1 (power density of 187.5 mW cm-3).

Prognostic Utility of Calcium Scoring as an Adjunct to Stress Myocardial Perfusion Scintigraphy in End-Stage Renal Disease.

Coronary artery calcium score (CACS) is a strong predictor of adverse cardiovascular events in the general population. Recent data confirm the prognostic utility of single-photon emission computed tomographic (SPECT) imaging in end-stage renal disease, but whether performing CACS as part of hybrid imaging improves risk prediction in this population is unclear. Consecutive patients (n = 284) were identified after referral to a university hospital for cardiovascular risk stratification in assessment for renal transplantation. Participants underwent technetium-99m SPECT imaging after exercise or standard adenosine stress in those unable to achieve 85% maximal heart rate; multislice CACS was also performed (Siemens Symbia T16, Siemens, Erlangen, Germany). Subjects with known coronary artery disease (n = 88) and those who underwent early revascularization (n = 2) were excluded. The primary outcome was a composite of death or first myocardial infarction. An abnormal SPECT perfusion result was seen in 22% (43 of 194) of subjects, whereas 45% (87 of 194) had at least moderate CACS (>100 U). The frequency of abnormal perfusion (summed stress score ≥4) increased with increasing CACS severity (p = 0.049). There were a total of 15 events (8 deaths, and 7 myocardial infarctions) after a median duration of 18 months (maximum follow-up 3.4 years). Univariate analysis showed diabetes mellitus (Hazard ratio [HR] 3.30, 95% CI 1.14 to 9.54; p = 0.028), abnormal perfusion on SPECT (HR 5.32, 95% CI 1.84 to 15.35; p = 0.002), and moderate-to-severe CACS (HR 3.55, 95% CI 1.11 to 11.35; p = 0.032) were all associated with the primary outcome. In a multivariate model, abnormal perfusion on SPECT (HR 4.18, 95% CI 1.43 to 12.27; p = 0.009), but not moderate-to-severe CACS (HR 2.50, 95% CI 0.76 to 8.20; p = 0.130), independently predicted all-cause death or myocardial infarction. The prognostic value of CACS was not incremental to clinical and SPECT perfusion data (global chi-square change = 2.52, p = 0.112). In conclusion, a perfusion defect on SPECT is an independent predictor of adverse outcome in potential renal transplant candidates regardless of the CACS. The use of CACS as an adjunct to SPECT perfusion data does not provide incremental prognostic utility for the prediction of mortality and nonfatal myocardial infarction in end-stage renal disease.

National administrative data produces an accurate and stable risk prediction model for short-term and 1-year mortality following cardiac surgery.

OBJECTIVES: Various risk models exist to predict short-term risk-adjusted outcomes after cardiac surgery. Statistical models constructed using clinical registry data usually perform better than those based on administrative datasets. We constructed a procedure-specific risk prediction model based on administrative hospital data for England and we compared its performance with the EuroSCORE (ES) and its variants. METHODS: The Hospital Episode Statistics (HES) risk prediction model was developed using administrative data linked to national mortality statistics register of patients undergoing CABG (35,115), valve surgery (18,353) and combined CABG and valve surgery (8392) from 2008 to 2011 in England and tested using an independent dataset sampled for the financial years 2011-2013. Specific models were constructed to predict mortality within 1-year post discharge. Comparisons with EuroSCORE models were performed on a local cohort of patients (2580) from 2008 to 2013. RESULTS: The discrimination of the HES model demonstrates a good performance for early and up to 1-year following surgery (c-stats: CABG 81.6%, 78.4%; isolated valve 78.6%, 77.8%; CABG & valve 76.4%, 72.0%), respectively. Extended testing in subsequent financial years shows that the models maintained performance outside the development period. Calibration of the HES model demonstrates a small difference (CABG 0.15%; isolated valve 0.39%; CABG & valve 0.63%) between observed and expected mortality rates and delivers a good estimate of risk. Discrimination for the HES model for in-hospital deaths is similar for CABG (logistic ES 79.0%) and combined CABG and valve surgery (logistic ES 71.6%) patients and superior for valve patients (logistic ES 70.9%) compared to the EuroSCORE models. The C-statistics of the EuroSCORE models for longer periods are numerically lower than that of the HES model. CONCLUSION: The national administrative dataset has produced an accurate, stable and clinically useful early and 1-year mortality prediction after cardiac surgery.