Prevalence of Obstructive Coronary Artery Disease in Ambulatory Patients with Stable Angina Pectoris

Background: Myocardial ischemia with its clinical symptom angina pectoris is associated with increased morbidity and mortality. Obstructive coronary artery disease (CAD) is not the only cause for cardiac ischemia and the prevalence of obstructive CAD in patients with stable angina pectoris is still discussed. Therefore, we investigated the prevalence of CAD in patients with stable angina pectoris undergoing coronary angiography. Methods: In a cross-sectional study, 2501 patients with stable angina pectoris scheduled for coronary angiography were observed in outpatient clinics in Germany. Baseline characteristics, results of ischemic stress testing, angina status as well as the result of the coronary angiography regarding the extent of coronary artery disease (CAD) were documented. Results: In 1049 from the 2501 patients, obstructive to CAD was documented as a pre-existing disease in the patient’s medical history, while the other 1452 patients had no previously documented CAD. In 85% of these patients with known CAD, the newly performed coronary angiography revealed progression of CAD as the most likely reason for angina pectoris symptoms. In contrast, only 16.5% had significant obstructive CAD documented by coronary angiography despite similar symptoms compared to patients with known CAD. Interestingly, only male sex, age over 65 years, dyslipidemia, as well as typical angina pectoris symptoms were predictive for obstructive CAD in a multivariate analysis performed in patients without known CAD. Other classic risk factors, including hypertension, smoking and the result of the ischemic stress test were not predictive for CAD in this group. Conclusion: In patients with known CAD, progression of the disease was common as a cause for angina pectoris symptoms. Newly diagnosed CAD was far less prevalent in patients without pre-existing CAD. This is clinically relevant since symptoms were similar in patients with and without pre-existing CAD. Other causes for cardiac ischemia including endothelial dysfunction and microvascular abnormalities may be relevant for the clinical symptomatology of patients with stable angina pectoris.