Abstract:
Objective To investigate the diagnostic value of cadmium zinc telluride (CZT) cardiac SPECT dynamic myocardial perfusion imaging (D-MPI) quantitative parameters in prognostic assessment of patients with ischaemia and non-obstructive coronary arteries (INOCA) and obstructive coronary artery disease (OCAD). These parameters were compared with myocardial perfusion imaging (MPI) semi-quantitative parameters.
Methods Retrospective analysis was performed on patients who received CZT cardiac SPECT D-MPI in TEDA International Cardiovascular Hospital from March 2020 to July 2021, had coronary angiography data before and after D-MPI, and completed follow-up. A total of 100 patients with INOCA (37 males and 63 females, aged 62.0(55.3, 66.0) years) and 203 patients with OCAD (122 males and 81 females, aged 63.0(57.0, 69.0) years) were followed for major adverse cardiovascular events (MACE). According to MACE results, patients with INOCA were divided into the MACE and non-MACE groups, similar to patients with OCAD. The D-MPI quantitative parameters (including myocardial flow reserve (MFR), rest myocardial blood flow (r-MBF), and stress myocardial blood flow (s-MBF)) and MPI semi-quantitative parameters (including summed stress score (SSS), summed rest score (SRS), summed different score (SDS), stress total perfusion defect (s-TPD) and rest total perfusion defect (r-TPD)) were compared between the MACE group and the non-MACE group. Two independent sample t-test or the Mann-Whitney U test were used to compare measurement data between groups, and the Pearson′s chi-square test was used to compare counting data between groups. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of quantitative parameters of D-MPI and semi-quantitative parameters of MPI in predicting MACE in patients with INOCA and OCAD. The Delong test and net reclassification index (NRI) were used to verify the differences in diagnostic efficacy between D-MPI quantitative parameters and MPI semi-quantitative parameters.
Results Among the 100 patients with INOCA, s-MBF and MFR in the MACE group were significantly lower than those in the non-MACE group (1.27(1.03, 1.88) ml/(min·g) vs. 2.25(1.59, 3.13) ml/(min·g); 1.65(1.35, 2.04) vs. 2.52(1.75, 3.39)), and the differences were statistically significant (Z=−2.986 and −2.859, both P<0.05). ROC curve analysis showed that s-MBF and MFR had high diagnostic efficiency in predicting MACE in patients with INOCA (area under curve (AUC)=0.777 and 0.765, both P<0.001). When the cut-off value of s-MBF was 1.57 mL/(min·g), the sensitivity and specificity of predicting MACE in patients with INOCA were 72.7% and 75.3%, respectively. When the cut-off value of MFR was 2.04, the sensitivity and specificity of predicting MACE in patients with INOCA were 81.8% and 66.3%, respectively. According to NRI results, the proportion of correct classification in prognosis of INOCA patients with s-MBF≤1.57 ml/(min·g) and MFR≤2.04 was 44.4% and 44.5% higher than that of abnormal MPI semi-quantitative parameters (SSS≥4 and SDS≥2). Among 203 patients with OCAD, s-MBF and MFR in the MACE group were significantly lower than those in the non-MACE group (1.21 (0.61, 1.51) ml/(min·g) vs. 1.76 (1.14, 2.56) ml/(min·g); 1.51 (0.81, 1.91) vs. 2.02(1.50, 2.86)), and the differences were statistically significant (Z=−2.891 and −2.984, both P<0.05). ROC curve analysis showed that MFR and s-MBF had high diagnostic efficacy in predicting MACE in patients with OCAD (AUC=0.725 and 0.718, both P<0.001). When the cut-off value of MFR was 1.71, the sensitivity and specificity of predicting MACE in patients with OCAD were 75.0% and 63.6%, respectively. When the cut-off value of s-MBF was 1.49 ml/(min·g), the sensitivity and specificity of predicting MACE in patients with OCAD were 81.3% and 61.5%, respectively. According to NRI results, the proportion of correct classification in prognosis of OCAD patients with s-MBF≤1.49 ml/(min·g) and MFR≤1.71 was 32.9% and 28.7% higher than that of abnormal MPI semi-quantitative parameters (SSS≥4 and SDS≥2).
Conclusions MFR and s-MBF obtained by CZT cardiac SPECT D-MPI can be used to indicate the occurence of MACE in patients with INOCA and OCAD and have good predictive diagnostic efficacy. Compared with MPI semi-quantitative parameters, MFR and s-MBF provide more accurate prognostic evaluation for clinical practice.