ATP-stress CTP an accurate tool for detection of myocardial ischaemia

Adenosine triphosphate (ATP)-stress myocardial computed tomography perfusion (CTP) correlates well with coronary flow velocity reserve (CFVR) for the assessment of myocardial ischaemia, a recent study has shown.

The study included 50 patients (mean age, 69.6±9.4 years; 76 percent male) with stable angina pectoris who underwent both ATP-stress CTP and CFVR imaging. Myocardial ischaemia in CTP was defined qualitatively as perfusion defects, and quantitatively as reductions in myocardial blood flow (MBF). In CFVR, a cut-off value of 2.0 was used during assessment.

Qualitatively, CTP identified myocardial ischaemia in the left anterior descending (LAD) artery region of 25 patients. The mean CFVR score in these regions was 1.9±0.6; in comparison, the average score in those without myocardial ischaemia, as qualitatively defined by CTP, was 2.9±0.8 (p<0.001).

Qualitative CTP was able to predict CFVR <2.0 with an 84.0-percent diagnostic accuracy, along with sensitivity and specificity values of 94.7 percent and 77.4 percent, respectively.

Quantitatively, MBF showed a significant and positive correlation with CFVR (r, 0.630; p<0.0001). Receiver operating characteristic curves identified an optimal MBF cut-off value of 1.43 mL/g/min. At this threshold, the area under the curve was 0.89 and the diagnostic accuracy for detecting CFVR <2.0 was 84.0 percent. The sensitivity and specificity were 94.7 percent and 77.4 percent, respectively

Combining both quantitative and qualitative evaluations, specificity jumped to 96.8 percent, and diagnostic accuracy improved to 94.0 percent.