Online Risk Calculator - Predicting the likelihood of CAD
The reference standard examination for diagnosing CAD is CCA. Though it is invasive and inherits a small risk of complications and even death during examination . The development of a noninvasive test could yield great advantages if its accuracy (in terms of sensitivity and specificity) is reasonably high. CT is such a test with high accuracy (see Background). Patients with suspected CAD but actually not having a significant stenosis would benefit the most from coronary CT angiography. Therefore, a prediction of the probability of having CAD seems to be substantially important, as patients with low-to-medium likelihood of CAD could be examined first by noninvasive CT angiography. The result of CT will then be used for updating the probability of CAD. This will provide further guidance for the next steps in clinically managing the patient.
Using a vast pool of studies with both CT and CCA results on an individual patient basis, we plan to develop three online calculators (including an application for mobile devices) for predicting the likelihood for CAD:
- Our first approach is a pretest likelihood prediction calculator based on the angina classification by Diamond and Forrester  using age, gender, and clinical presentation as the predictive effects of these factors are greater compared to other risk factors such as diabetes or smoking. Recently published models by Genders et al. [2, 3] seem to be very promising and enforce us in our investigation.
- In addition, a calculator is planned which also incorporates the result from the CT examination and thus provides posttest likelihoods of CAD. By doing this, we will be able to deliver an easy-to-use but powerful tool for everyday practice which supports doctors in making the right decisions for their patients and, in consequence, reduces the amount of unnecessary CCAs.
- To use the best achievable information from a patient, we plan to develop a prediction model including the above-mentioned values and additionally include other risk factors as, for example, Agatston Calcium-Score or smoking status.