Myocardial perfusion scintigraphy: effect on diagnostic and clinical management algorithms

Research has demonstrated that myocardial perfusion imaging increases the sensitivity and specificity of stress electrocardiography. However, the additional effect of the perfusion component of a stress study on clinical management algorithms remains poorly defined.

We prospectively assessed the decision-making process in 518 patients, from 191 clinicians, undergoing stress myocardial perfusion imaging in our departments. Each clinician was asked, by telephone interview, to define the probability of reversible myocardial ischemia and their management plan (i.e., no antianginal treatment, medical therapy or an invasive intervention) in three stages: pretest, after the stress data was made available and after completion of the perfusion study.

The results of the stress data alone influenced the estimate of the probability of reversible ischemia in 149 of 518 patients, and management strategy in 50 of 518 patients. The data from the perfusion component in isolation changed probability of reversible disease in 219 of 518 patients and altered clinical management in 77 of 518 patients. Of 103 patients in whom an invasive procedure was planned after the stress data, the availability of the perfusion data led to deferral of catheterization in 48 cases (46.6%). Conversely, of the 415 patients triaged to a noninvasive plan after stress data, only 29 (7.0%) were changed to an invasive strategy. Of note, only 2.3% of women changed from a conservative strategy as a consequence of the perfusion data, compared to 9.1% of men.

The perfusion component of a stress study has a significant effect on both estimation of clinical probability and the definition of patient management strategy. Myocardial perfusion imaging reduced the number of catheterizations in patients initially triaged to an invasive management strategy. Conversely, the effect of stress and perfusion data in patients triaged to conservative management on clinical grounds, especially women, remains less well defined.