Impact of initial myocardial perfusion imaging versus invasive coronary angiography on outcomes in coronary artery disease: a nationwide cohort study

Purpose In patients with stable coronary artery disease (CAD), two main options exist to guide management: initial invasive coronary angiography (CAG), or selective CAG after risk stratification using myocardial perfusion imaging (MPI). This study compared clinical outcomes between these two strategies in a large, real-world population. Methods The initial cohort comprised 1,000,000 randomly selected patients who had been entered in the National Health Insurance Research Database of Taiwan between 2000 and 2011. Patients with acute coronary syndromes, prior myocardial infarction (MI) or coronary revascularization, and prior treadmill testing or stress echocardiography were excluded. The remaining patients with suspected or known CAD were divided into those in whom initial CAG had been performed and those in whom initial MPI had been performed, and were followed until the end of 2011 for all-cause mortality, MI, and revascularization. A Cox proportional hazards model was used to estimate the risk of events after adjusting for covariates. Results The MPI and CAG groups each comprised 4,495 patients after frequency matching, with a similar Charlson comorbidity index (CCI). The MPI group had a significantly and dramatically lower incidence of revascularization (729 vs. 2,380, p < 0.001), MI (268 vs. 1,044, p < 0.001), and all-cause mortality (522 vs. 784, p < 0.001) than the CAG group. Multivariable analysis adjusting for age, gender, CCI, and comorbidities showed that in the MPI group fewer patients had revascularization (HR 0.24, 95% CI 0.22-0.26) and MI (HR 0.23, 95% CI 0.20-0.26), and the rate of all-cause mortality was lower (HR 0.58, 95% CI 0.52-0.64). Conclusions In patients with suspected stable CAD, compared with initial invasive CAG, a selective strategy guided by MPI was associated with lower rates of revascularization and MI and improved survival.