Clinical Symptoms and Angiographic Findings of Patients Undergoing Elective Coronary Angiography without Prior Stress Testing

Abstract

Background: Many patients undergo elective coronary angiography without prior stress testing, precluding an assessment of their appropriateness for percutaneous coronary intervention (PCI). If, however, these patients have more severe angina or obstructive coronary artery disease (CAD), proceeding directly to angiography would represent efficient resource utilization. Methods: We identified patients without a prior history of obstructive CAD undergoing elective coronary angiography performed between July 2009 and March 2012 in the NCDR CathPCI Registry® and assessed for differences in angina (Canadian Cardiovascular Society [CCS] class) and severity of obstructive CAD (70% stenosis in an epicardial or 50% in a left main coronary artery) in those with and without pre-procedural stress testing. Given the large sample size, differences were considered clinically meaningful if the standardized difference was 10%. To further understand whether proceeding to coronary angiography without prior stress testing was justified because of a high clinical pre-test probability for CAD, we also compared the frequency of obstructive CAD. Results: Of 403,182 patients undergoing elective coronary angiography, nearly half (49.7%) were performed without prior stress testing. Patients without prior stress testing were more frequently asymptomatic (CCS class 0), as compared with those who had prior stress testing (40.5% vs. 28.7%; standardized difference 19.1%). There were no meaningful differences in the frequency of proximal LAD (5.1 % in no stress test group vs. 6.4% in stress test group; standardized difference 5.7%), left main (2.9% vs. 3.5%; standardized difference 3.5%) or 3-vessel CAD (4.4% vs. 6.1%; standardized difference 6.0%) between the 2 groups. Moreover, the likelihood of obstructive CAD in patients undergoing coronary angiography without prior stress testing was 18.0%, as compared with 43.0%, 22.9%, and 12.6% for those with stress testing showing severe, moderate, and mild ischemia. Conclusion: In elective angiography, proceeding to coronary angiography without prior stress testing was not associated with greater symptoms, higher-risk coronary anatomy, nor a greater presence of obstructive CAD. Many angiographic procedures might be avoided with pre-procedural stress testing.