Purpose: to assess diagnostic capabilities of single-photon emission computed tomography (SPECT) in the detection of obstructive coronary artery (CA) lesions, depending on the meeting appropriate use criteria.
Materials and methods: We used in this retrospective analysis data from 107 patients with previously diagnosed ischemic heart disease (IHD) or in need to exclude it, who were hospitalized in inpatient departments of the Research Institute for Complex Issues of Cardiovascular Diseases in the period from 2012 to 2015. All patients underwent coronary angiography (CAG) and SPECT (the time interval between the studies did not exceed 3 months) for detection of hemodynamically significant CA stenoses. Patients were distributed into two groups according SPECT imaging appropriateness score: group 1-88 patients with score 7-9 (in whom SPECT imaging was appropriate), group 2-19 patients with score 1-6 (in whom SPECT imaging was uncertain, possibly appropriate, or inappropriate.
Results: Clinical signs and symptoms of angina pectoris were predominantly found in group 1 patients (p=0.499). Asymptomatic patients were more likely to be found in group 2 (p<0.001). Group 1 patients commonly had high pretest probability (PTP) (over 90 %, p<0.001), whereas group 2 patients commonly had low PTP (5-10 %, p<0.001). Mean PTP was 77 and 58 % in groups 1 and 2, respectively (p=0.003). According to positive SPECT imaging, significant CA lesions were more often found in group 1 compared to group 2 (31.8 and 10.5 %, respectively, p=0.060). Two- and three-vessel disease prevailed in group 1 (25 % and 14.7 %) according the analysis of prevalence and location of hemodynamically significant CA lesions, although the data did not reach statistical significance (p=0.057 and p=0.073). Stenoses >70 % were more commonly detected in group 1, compared to group 2: in anterior descending artery 52.3 vs. 5.3 % (p<0.001), circumflex artery 35.2 vs. 10.5 %; (p=0.034), right coronary artery 34.1 vs. 10.5 % (p=0.041). The sensitivity in both groups was rather low (40 % vs. 25 %), whereas specificity was 83 % in group 1 and 93 % in group 2.
Conclusion: According to clinical examination, patients with IHD and indications for SPECT imaging more often had obstructive CA lesions (63.6 %), than patients with questionable or no indications (21.1 %). However, rate of positive findings during stress tests with SPECT imaging was low in both groups and did not differ significantly (p=0.06). Despite high specificity of SPECT imaging, its sensitivity was low in both groups.