Prognostic Value of Myocardial Perfusion Scintigraphy with IQ∙SPECT Technology in Patients with Suspected or Known Coronary Artery Disease

Abstract

Background:

IQ∙SPECT is a collimator design coupled with a cardio-centric acquisition orbit and specific reconstruction algorithm that increases camera efficiency. However, there is no prognostic data derived from IQ∙SPECT exams.

Objectives:

To evaluate the prognostic value of IQ∙SPECT myocardial perfusion scintigraphy (MPS) in patients with suspected or known coronary artery disease (CAD).

Methods:

The study population consisted of 734 consecutive patients with suspected or known CAD submitted to MPS with IQ∙SPECT. Adequate follow-up was obtained in 625 patients. We retrospectively analyzed imaging and clinical data. The follow-up was obtained for no less than 12 months after the MPS study. Statistical significance was taken at p < 0.05.

Results:

Normal IQ∙SPECT compared to abnormal IQ∙SPECT had lower annualized incidence of hard events (0.2% and 1.1%, respectively, p = 0.02), late combined events (1.1% and 5.5%, respectively, p = 0.008), and revascularization (1% and 14%, respectively, p < 0.001). Left ventricular ejection fraction ≤ 45% was found to be the only clinical predictor of hard events (p < 0.0003, confidence interval [CI] = 5.25 to 129.02). However, for combined events, abnormal MPS (p < 0.0001, CI = 3.39 to 11.13, hazard ratio [HR] = 6.14) and dyspnea/fatigue (p = 0.013, CI = 1.28 to 8.4, HR = 3.3) obtained statistical significance. In contrast, ischemic burden ≥ 5% (p < 0.0001, HR = 30.3) was the most relevant parameter for revascularization, followed by thoracic pain (p = 0.002, HR = 2.4).

Conclusion:

Our study demonstrates that IQ SPECT MPS has significant prognostic capabilities with very low risk of adverse events in patients with normal findings.