[Diagnostic accuracy of adenosine triphosphate stress echocardiography derived coronary flow reserve for detecting significant coronary stenosis].

OBJECTIVE: To assess the diagnostic accuracy of coronary flow reserve measured by transthoracic Doppler echocardiography (TTDE) associated with adenosine triphosphate (ATP) stress for detecting coronary stenosis in patients with chest pain. METHODS: A total of 125 patients scheduled for elective coronary angiography (CAG) due to chest pain were recruited. ATP stress echocardiography were performed to measure CFR in left anterior descending (LAD) by TTDE with 2 days pre-CAG. Coronary flow reserve (CFR) was calculated as peak diastolic velocity during maximum hyperemia (PDV2) divided by baseline (PDV1). According to the coronary angiography results, all patients were divided into group A (stenosis < 50% in LAD, n = 57), group B (stenosis of 50% - 75% in LAD, n = 20) and group C (stenosis > 75% in LAD, n = 48). Then CFR was compared among three groups. The receiver operating characteristic curve (ROC) was used to assess the value of CFR for detecting LAD stenosis. RESULTS: CFR was significantly different among three groups (group A: 3.02 ± 0.85, group B: 2.49 ± 0.65, group C: 1.82 ± 0.56; all P < 0.01). With ROC analysis, CFR < 2.2 was the best cut-off value for diagnosing significant LAD stenosis (area under curve: 0.86 (95% CI 0.80 to 0.93)), with sensitivity of 81%, specificity of 83% and accuracy of 82%; CFR < 2.2 for diagnosing LAD stenosis > 50% (area under curve: 0.81 (95%CI 0.74 - 0.89, P < 0.01)), with a sensitivity of 59%, a specificity of 82% and an accuracy of 70%. CONCLUSIONS: CFR measured by TTDE associated with ATP stress is a valuable tool for screening significant stenosis in patients with chest pain. Its advantages are non-invasiveness, easy availability, safety and inexpensiveness.