The effect of beta-blockers on the diagnostic accuracy of vasodilator pharmacologic SPECT myocardial perfusion imaging

Background  The effect of beta (β) blockers on the accuracy, particularly the sensitivity, of vasodilator radionuclide myocardial perfusion imaging (MPI) is not entirely clear. This study aimed to further assess the effect of β-blockers on the ability of MPI to identify significant and high-risk coronary artery disease (CAD). Methods and Results  For 555 patients who underwent vasodilator MPI and had coronary angiography within 90 days, global and per-vessel sensitivities and specificities were calculated, and were found to be similar between patients taking β-blockers and those who were not. β-blockers did not decrease the ability to detect patients with multivessel disease. Summed stress scores and summed rest scores were likewise similar in both groups. To account in part for catheterization referral bias and the potential of false-negative MPI studies in patients receiving β-blockers, survival analysis was performed on 2646 patients with normal MPI studies who did not undergo cardiac catheterization and failed to demonstrate significant mortality difference related to the taking of β-blockers. Conclusions  β-blocker therapy does not diminish the ability of vasodilator stress MPI to detect clinically significant CAD, nor hide the mortality risk of patients with normal studies not referred for catheterization. Presented in part at the American Society of Nuclear Cardiology 9th Scientific Session, September 2004, New York, NY.