  The coronary artery disease (CAD) involves narrowing and damaging the major
blood vessels has become the most life threating disease in the world
especially in south Asian reason. Although outstanding medical facilities are
available in Singapore and India for CAD patients, early detection of CAD
stages are necessary to minimize the patients' sufferings and expenses. It is
really challenging for doctors to incorporate numerous factors for details
analysis and CAD detections are expensive as it needs expensive medical
facilities. Clinical Decision Support Systems (CDSS) may assist to analyze
numerous factors for patients. In this paper, a Rule Based Expert System (RBES)
is proposed which can predict five different stages of CAD. RBES contains five
different Belief Rule Based (BRB) systems and the final output is produced by
combining all BRBs using the Evidential Reasoning (ER). Success, Error,
Failure, False Omission rates are calculated to measures the performance of the
RBES. The Success Rate and False Omission Rate show better performance
comparing to existing CDSS.
