Combined single-photon emission computed tomography-myocardial perfusion imaging with coronary calcium score for assessing coronary disease
Enrico Calandri, Monica Verdoia, Roberta Sirovich, Maria Teresa Giraudo, Mirco Pultrone, Viviana Frantellizzi, Orazio Viola, Francesca Crivelli, Sonya Gallina, Monica Serralunga, Andrea Rognoni, Giuseppe De VincentisPurpose
Coronary artery disease (CAD) underestimation represents a major pitfall of single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI). Coronary artery calcium score (CACS) has emerged as a sensitive tool for the assessment of suspect CAD; however, the integration of SPECT-MPI with CACS has been seldom evaluated, so far, and was therefore the aim of the present study.
Methods
Patients undergoing SPECT-MPI with CACS and subsequent coronary angiography were included. ROC curves were used to identify the CACS values best predictive for CAD. In SPECT-MPI negative patients, the formula: defined the optimal CACS cut-points. The Systematic Coronary Risk Evaluation 2 was applied for 10-year cardiovascular risk estimation. Significant CAD was defined for an epicardial coronary stenosis >70 or 50% for the left main.
Results
Among 124 patients, 61 (49.19%) displayed positive SPECT-MPI, whereas 69 (56%) had significant CAD at angiography. Sensitivity, specificity, and positive predictive value (PPV) for SPECT-MPI were, respectively, 74, 82, and 84%. Considering 63 SPECT-MPI negative cases, the index values for CACS at the optimal cutoff value of 1949 were: sensitivity 28%, specificity 89%, and PPV 50%, allowing to further detect five (8%) of the patients with significant CAD. The increased discriminative power of the combined SPECT-MPI with CACS was not conditioned by the pretest cardiovascular risk.
Conclusion
Among patients with suspect CAD undergoing SPECT-MPI, the addition of CACS in negative cases allows to detect a consistent further 8% of patients with significant CAD, thus limiting the risk of disease underestimation and offering potential prognostic benefits.