Assessment of the severity of coronary artery stenosis by the ratio of the regional washout rate determined by adenosine triphosphate stress Tl-201 SPECT

Coronary vasospasm produces reversible perfusion defects observed during adenosine triphosphate stress myocardial single-photon emission computed tomography

BACKGROUND

Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP-SPECT) is useful for diagnosing coronary artery disease (CAD), although sometimes false positive results are observed. It has not been established whether a coronary spasm is responsible for the false positive findings during ATP-SPECT.

HYPOTHESIS

We investigated whether coronary spasm is one of the factors which produces reversible defects on ATP-SPECT.

METHODS

Eighty-six patients (mean age: 62 y; 58 men) who underwent both spasm-provocation testing by coronary angiography and ATP-SPECT, were selected for the study. Patients with coronary narrowing (>30%), myocardial infarction, or heart failure were excluded. Patients were divided into 2 groups based on whether the spasm-provocation test result was positive (vasospastic angina [VSA] group, n = 46) or negative (non-VSA group, n = 39).

RESULTS

The body mass index was lower in the VSA group than in the non-VSA group (p = 0.005). On ATP-SPECT imaging, any type of reversible defect was observed more frequently in the VSA group (68%) than in the non-VSA group (36%, p = 0.0027). Logistic regression analysis demonstrated that the presence of reversible defects was one of the factors accounting for the presence of coronary vasospasm (p = 0.0022, R2 = 0.172).

CONCLUSIONS

The findings suggest that reversible defects on ATP-SPECT imaging are frequently present in patients with coronary vasospasm. Coronary spasm may be considered as 1 of the factors, which produce reversible defects on ATP-SPECT, observed in patients with chest symptoms and angiographically normal coronary arteries.

Detection of significant stenotic lesions in the left anterior descending coronary artery using adenosine triphosphate stress strain imaging: comparison with coronary flow velocity reserve measurement using transthoracic Doppler echocardiography

To evaluate the usefulness of adenosine triphosphate stress strain imaging for detecting significant coronary artery disease in the left anterior descending coronary artery (LAD), 34 patients underwent coronary flow velocity reserve measurement in the distal LAD and adenosine triphosphate stress strain imaging simultaneously. Time to peak strain (TPS) was measured in the apical septal segment. TPS ratio was obtained as the ratio between TPS at adenosine triphosphate stress and at baseline. TPS ratio in 11 patients with LAD lesions was significantly greater than that in 23 patients without LAD lesions (1.24 +/- 0.17 vs 0.92 +/- 0.12, respectively, P < .0001). With a cut-off value greater than or equal to 1.1 for the TPS ratio and less than 2.0 for the coronary flow velocity reserve, diagnostic accuracy for the presence of significant LAD lesions were 88% and 82%, respectively. In conclusion, strain imaging can differentiate ischemic and nonischemic myocardium accurately comparable with coronary flow velocity reserve measurement.