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UCLB E-Lucid
  • FILES (8)

PLEASE NOTE that licensees are NOT permitted to further distribute the software nor allow the software to be used by, on behalf of or for the benefit of any third parties.

Version 2.2 of the PRAiS software is now available for download. The only significant difference from the previous version is that the risk model has been recalibrated on revised 2009-2012 national data, which will result in slightly different estimated risks for some surgical episodes.


Product specification

This software can be used to apply the PRAiS risk model for death within 30 days following cardiac surgery in children using routinely collected audit data and produce a Variable Life Adjusted Display (VLAD) chart to facilitate routine monitoring of programme-level outcomes. 

Product update

We have updated the original PRAiS software to version 2.0. Main changes include:

  • Recalibrated risk model on 2009-2012 national UK CCAD data;
  • Implementation of the May 2013 CCAD specific procedure algorithm to allow generation of this risk factor within the PRAiS software;
  • Automated removal of excluded procedure types;
  • Now allowed up to 8 comorbidity and 8 procedure codes.

Product description

The Excel file “Monitoring Outcomes with PRAiS v2.0.xls” is designed to allow UK paediatric cardiac centres to routinely monitor their short term surgical outcomes using the data that they collect for the Central Cardiac Audit Database (CCAD). Outcomes are partially risk adjusted using a model that estimates the risk of death within 30 days of a surgical procedure based on specific procedure, age, weight and a patient's recorded diagnoses and co-morbidities.

Outcomes over time are displayed using a bespoke version of the Variable Life Adjusted Display (VLAD) technique which is intended to facilitate the monitoring of clinical outcomes. The VLAD chart is a plot of the difference between the expected and actual tally of deaths. The plotted trace will rise for each survival and fall for each death, the height of the fall or rise depending on the estimated probability of death for that episode. The survival of a high risk episode results in a larger rise than the survival of a low risk episode and a death of a low risk episode results in a larger fall than a death of a high risk episode. In this way, the VLAD chart can help to identify runs of outcomes that are better or worse than expected, based on partial risk adjustment. If the VLAD plot goes down over time, there have been more deaths than expected and if it climbs, there have been more survivors than expected. If it fluctuates around the horizontal, then outcomes are broadly in line with expectations. We additionally highlight episodes where there was a reintervention within 30 days as part of the VLAD chart.

Example output of a VLAD chart for 1000 hypothetical episodes is shown below. This is just an illustrative example and does not correspond to actual data.

Example of a VLAD chart. This hypothetical unit had a run of survivors in early 2011 followed by a run of deaths in the spring of 2011. There were also clusters of reinterventions in the summer and autumn. Note that this is an illustrative example and does NOT correspond to actual data.

We stress that VLAD incorporates no statistical tests of “significance”; it is intended to provide a visual aid to monitor outcomes after partial risk adjustment.

Users can enter data directly into the software in the format it is submitted to the National Institute of Cardiovascular Outcomes (NICOR) Central Cardiac Audit Database (CCAD). All pre-processing is performed as part of the software, including basic error and consistency checking.

After data are pre-processed, an estimated risk of death within 30 days following surgery is calculated for each surgical episode and a VLAD chart generated over the time period of the included data. To facilitate discussion of any deaths during the period, information on these patients is copied to a separate worksheet.

The software includes additional, optional, functionality for units to examine their recent case mix by bands of estimated risk of death and by mix of patients with different clinical features, along with a comparison to historical national data for interest. The software also includes a function to generate prediction limits for observed 30-day survival among surgical episodes.


Generating new VLADs is very easy – simply put the new data in the relevant worksheet and the software will reset all the other sheets as necessary when rerunning the model. 

Further information can be found on the UCL research group's webpage at:

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Excel software to implement PRAiS risk model using routine audit data

Please check carefully that the terms you select correspond to your intended use of the product.

PRAiS UK Licence 1.00

For internal use by UK paediatric cardiac centres

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Term: perpetual (does not require renewal)
Seats: n/a

Price excl. VAT: £3000.00

Licence - Other Use 1.00

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Further details
Term: perpetual (does not require renewal)
Seats: n/a

Price excl. VAT: P.O.A. (price on application)

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