When opposite opinions are both right

YOU have chest pain and have undergone testing for your heart arteries and were told that you have a significantly blocked artery (at least 50 per cent diameter narrowing of the artery). You decided to do another test to confirm the finding and were then told by another doctor that you do not have significant narrowing of the heart artery. You are confused now and wonder whether one of the tests is inaccurate. You will be surprised when told that both tests were correctly interpreted. How then can both tests be correctly interpreted - and there are two totally different results?

Limitations of the gold standard

To unravel this mystery, one needs to understand the limitations of the tests being used to diagnose the presence of narrowed heart arteries. Coronary angiography (CAG) is currently the gold standard for the assessment of narrowing of the heart arteries and it involves the insertion of a plastic tubing through the wrist or groin artery under local anaesthesia into the opening of the heart arteries and injecting iodine based contrast agents into the heart arteries and taking X-ray images of the heart arteries.