The role of calcium score and CT angiography in the medical management of patients with normal myocardial perfusion imaging.

BACKGROUND

Individuals with normal myocardial perfusion imaging (MPI) may still have substantial coronary artery disease (CAD), which would benefit from aggressive medical therapy. The role of coronary artery calcium-score (CAC) and/or coronary CT Angiography (CTA) to identify additional treatment candidates in this population is unknown.

METHODS

Ninety-four patients completed the study protocol and underwent CAC and CTA after MPI.

RESULTS

In 81 patients who had a normal MPI, an algorithm using the clinical predictors, CAC, and then CTA was created to identify candidates for aggressive medical management; 24/81 patients had a high Framingham Risk Score (FRS) or diabetes, and need aggressive medical management, while 6/81 patients had a low FRS and low post-MPI probability of CAD. The use of CAC in 51/81 patients with intermediate clinical predictors would identify 23/51 patients with low risk (CAC < 100) and 11/51 patients (CAC > 400) for aggressive medical management. The remaining 17/51 patients with intermediate CAC scores (100-399) would require CTA, of which, would identify 8/17 additional patients with >50% stenosis for aggressive medical therapy.

CONCLUSION

A stepwise approach including history, CAC and CTA can identify about 50% of the patients with normal MPI who have a higher risk and may benefit from aggressive medical management.