Creating a web application that combines Framingham risk with Electron Beam CT Coronary Calcium Score to calculate a new event risk.

The Electron Beam CT (EBT) Coronary Calcium Score (CCS) is an independent predictor of coronary events and adds incremental information to standard risk factors. How to use this information was uncertain. To assist our referring physicians in utilizing this test, a web based calculator was created that combines the Framingham score risk with the EBT CCS risk to obtain a new risk for cardiac events. To create this calculator, CCS breakpoints of 0, 80, 400, and 600 were selected; and from these breakpoints, 5 ranges of calcium scores: 0, 1-80, 81-400, 401-600, and >600 were defined. Bayes theorem was used to derive equations for the combined Framingham score risk and calcium score range risk for each CCS range. The sensitivity and specificity of each of these CCS breakpoints for the prediction of events was derived from prospective studies. These equations were then translated into a JavaScript program that could be accessed from a web browser. This calculator can be easily used to restratify many individuals classified as low, intermediate, or even high risk according to the Framingham risk score system into a different risk group, allowing more appropriate matching of intervention intensity with absolute cardiovascular event risk.