Diagnostic pathways for women with suspected coronary artery disease including cardiac SPECT/CT. 6-year experience in Latvia

Introduction Myocardial perfusion imaging with cardiac SPECT/CT is one of the most performed non-invasive cardiac imaging tests evaluating myocardial viability, assessing prognosis, and estimating the efficacy of therapy. The diagnostic algorithm should be applied individually for every patient group. Purpose To analyze the diagnostic pathways for women with suspected coronary artery disease (CAD) in Latvia including cardiac nuclear imaging and to investigate prescribed further diagnostic approaches to establish the diagnosis and appropriate treatment. Methods For women included in Latvian cardiac SPECT/CT registry the cardiac SPECT/CT was performed in a single University Hospital from 2018 till 2023. For all of them the previous exercise stress test was performed. The patients were divided into 2 groups: normal myocardial perfusion and true myocardial perfusion defect, defined as area of ischemia ≥ 10% of the left ventricle myocardium. Patients with perfusion defect were analyzed according to prescribed further diagnostic test or treatment option. Results 916 women with known or suspected CAD were analyzed. True myocardial perfusion defect was detected in 175 patients (19.1%). The previous exercise stress test was positive only in 92 (52.6%) women with perfusion defect in SPECT/CT. As further diagnostic approach in 40 (22.9%) cases cardiac computed tomography angiography (CTA) was suggested and the invasive coronary angiography (ICA) - in 135 (77.1%) cases. The patients without performed further diagnostic tests were excluded. Analyzing results of all performed CTAs’ (n=32), stenosis in main coronary arteries were found in 2 cases (6.25%) and patients were referred to percutaneous coronary intervention (PCI). Of all performed ICA(n=113), in 71 (62.8%) women atherosclerosis in main coronary arteries was not observed and INOCA (ischemia with non-obstructive coronary arteries) as a primary diagnosis was suspected. In 34 (30.1%) patients the significant stenosis in main coronary arteries was present and PCI was performed, of whom 13 (38.2%) women were primarily diagnosed. 2 patients (1.8%) underwent coronary artery bypass surgery (CBP). Conclusion The diagnostic algorithm including cardiac SPECT/CT is valuable and highly recommended for the diagnostics of women with known or suspected CAD. Knowing the relatively low specificity of exercise stress test for women, the cardiac SPECT/CT should be performed as an initial diagnostic test for women with intermediate and high pre-test probability. In patients with defined perfusion defect, but non-obstructive coronary arteries – the invasive physiology testing should be performed to assess microvascular function.