Potential impact of myocardial perfusion scintigraphy as gatekeeper for invasive examination and treatment in patients with stable angina pectoris: observational study without post-test referral bias

Aims To evaluate the impact of using myocardial perfusion scintigraphy (MPS) as gatekeeper for coronary angiography and revascularization in stable angina pectoris. Methods and results A prospective series of 507 out of 972 adult patients referred to coronary angiography for known or suspected stable angina pectoris underwent clinical examination followed immediately by MPS, the result of which was not communicated. MPS showed normal perfusion in 258/507 (51%) patients, reversible defects in 201/507 (40%), and fixed defects in 48/507 (9%). Of 168 revascularized patients, 27 (16%) had normal perfusion and 13 (8%) had fixed defects. Coronary angiography was undertaken in 476 patients of whom 252 (53%) had normal findings or insignificant stenoses. The same was the case in 361 (41%) out of the 883 of the 972 consecutive patients, who had this examination. Assuming that the true rate of normal perfusion in the entire series was correspondingly lower, 48% of catheterizations and 19% of revascularizations were superfluous. Conclusion The use of MPS as gatekeeper appears to make about half of catheterizations and almost one-fifth of revascularizations redundant. Even in high-risk groups, substantial savings are possible, and the risk of overlooking patients with severe disease seems negligible.