Stable angina and ST-segment depression: diagnostic value in patients undergoing coronary angiography

Clinical history and exercise testing (ET) are the main methods used to screen for coronary artery disease (CAD). Correct interpretation of such data is essential in determining diagnostic and treatment strategies.

To assess the diagnostic value of stable angina (SA) and ET in patients with suspected CAD undergoing coronary angiography and to compare results between the sexes.

We assessed 62 patients undergoing coronary angiography; ET was performed in 54 of them, being considered positive for ischemia in cases of ST-segment depression of > or =1 mm. The coronary angiograms were analyzed by two observers and patients were divided into two groups depending on the severity of CAD: Group 1: > or =70% stenosis (n=26), and Group 2: <70% stenosis (n=36).

The patients' mean age was 58+/-9 years, and 55% were male. SA was found in 24% of cases and ET was positive for ischemia in 53%. SA showed a sensitivity of 46.1%, specificity 91.7%, positive predictive value (PPV) 80%, negative predictive value (NPV) 70%, positive likelihood ratio (LR+) 5.1 and negative likelihood ratio (LR-) 0.6, while the corresponding results for ET were sensitivity of 70.8%, specificity 60%, PPV 59%, NPV 72%, LR+ 1.75 and LR- 0.5. SA was shown to have a greater NPV in women, and the LR+ was also significantly higher in women.

SA was shown to be a good diagnostic marker, with high specificity and PPV. The greater NPV and LR+ in women was shown to be superior for post-test prediction of angina. ET results were similar for both sexes and showed similar sensitivity and specificity to that reported in the literature.