Prognostic significance of coronary artery calcium scoring and single-photon emission computed tomographic myocardial perfusion imaging on major adverse cardiac events in patients at low risk for suspected coronary artery disease.

Background

To explore the prognostic value of combination of coronary artery calcium scoring (CACS) and single-photon emission computed tomography (SPECT) on the long-term risk of major adverse cardiac events (MACEs) in Chinese patients at low risk of suspected coronary artery disease (CAD).

Methods

The medical records of 1876 adult patients who were referred for clinically indicated non-invasive CAD detection with SPECT/CT from January 2011 to December 2013 were retrospectively reviewed. The primary outcome was the occurrence of MACEs, including cardiac death, non-fatal myocardial infarction (MI), unstable angina (UA), and late revascularisation.

Results

During a median follow-up of 28.4 ± 9.1 months, 210 patients were identified to have at least one MACEs. Multivariate Cox regression analysis showed that patients with abnormal SPECT had more MACEs compared to those with normal SPECT (HR = 3.41, 95% CI: 2.08-4.71, p < .01). Both moderate (HR = 3.35, 95% CI: 1.76-4.32, p < .01) and severe CACS (HR = 6.56, 95% CI: 4.71-8.23, p < .01) were associated with occurrence of HACEs compared with normal CACS. Moreover, interaction terms for CACS and SPECT findings were reported to be significantly associated with MACE outcomes (p < .01).

Conclusions

CACS and SPECT provided both independent and compensatory prognostic information for risk of MACE in patients at low risk of suspected CAD. Our findings strongly support adding a CACS testing in addition to SPECT in asymptomatic patients to better define the risk of cardiac events during follow-up.