Diagnostic Performance of SPECT in Patients with Coronary Microcirculation Disturbance after PCI

Background Patients after percutaneous coronary intervention (PCI) may still experience typical angina, potentially due to concomitant coronary microcirculation disturbance (CMD). Single-photon emission computed tomography (SPECT) serves as a non-invasive method for quantitatively assessing coronary flow reserve (CFR) in CMD patients. However, research on its diagnostic performance in this population is limited. Objective To evaluate the diagnostic performance of SPECT in patients with CMD after PCI by using upgraded acquisition techniques and novel myocardial blood flow quantitative analysis software. Methods A total of 32 patients who still had typical angina symptoms after PCI for coronary artery disease in Shaanxi Provincial People's Hospital between November 2020 and November 2021 were included in the study. General data of the patients were collected. Coronary angiography was performed, the fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) were measured using a temperature/pressure guidewire, and patients with FFR>0.8 and no pericardial subvascular obstructive stenosis postoperatively were selected, encompassing 60 vessels in total. Pearson's test was used to explore the correlation between IMR and CFR. With IMR as the gold standard, a receiver operating characteristic (ROC) curve was plotted for CFR in diagnosing CMD, and the area under the ROC curve (AUC) was calculated. Results Twenty CMD patients were included in the study, comprising 15 males and 5 females, with an average age of (64.2±9.3) years. Of the 60 vessels included, 21 were left anterior descending, 17 were left circumflex, and 22 were right coronary arteries. Pearson's test showed a negative correlation between IMR and CFR (r=-0.526, P<0.001). The AUC for CFR in diagnosing CMD was 0.840 (95%CI=0.716-0.964), the truncation value is 1.985. Conclusion SPECT has demonstrated good diagnostic performance in patients after PCI. Upgraded acquisition techniques and novel myocardial blood flow quantitative analysis software make SPECT an effective tool for diagnosing the presence of CMD in patients without pericardial subvascular obstructive stenosis after PCI.