Abstract 10422: Correlation of Real Time Myocardial Perfusion Imaging During Dobutamine Stress Echocardiography with Fractional Flow Reserve (FFR) Assessments
Background. The detection of microvascular perfusion defects with real time perfusion imaging (RTMCE) during dobutamine stress echocardiography (DSE) improves the detection of coronary artery disease (CAD) detected at angiography. Although a ≥50% diameter stenosis is considered physiologically relevant, fractional flow reserve (FFR) measurements in these vessels obtained at angiography may not be abnormal. Conversely, microvascular abnormalities may be present despite normal FFR measurements. The purpose of his project was to correlate perfusion assessments determined by RTMCE during DSE with this invasive functional assessment of stenosis severity.
Methods. A total of 32 vessels with ≥50% diameter stenosis were evaluated with FFR in 28 patients (age 60 ± 11 years; 12 women). All patients had RTMCE performed using an incremental dobutamine stress protocol, and myocardial perfusion assessed using a continuous infusion of ultrasound contrast (3% Definity). The presence or absence of inducible perfusion defects were correlated with FFR measurements of the coronary artery supplying the CA. All FFR measurements were within one month of the DSE. FFR was defined as distal pressure divided by mean aortic pressure during maximal hyperemia (normal value <0.8).
Results. The range of stenosis severity was 50-80% (mean 59 ±10 %). Nine lesions (28%) had FFR ≤ 0.8. Sensitivity and specificity of an induced perfusion defect during DSE to detect CATs supplied by territories with FFR <0.8 was 100% and 39%,respectively. In 14 vessels (44%), FFR was considered normal despite the presence of an induced perfusion defect and a ≥50% diameter stenosis by QCA.
Conclusions. RTMCE during DSE has excellent sensitivity for detecting coronary stenoses which have impaired FFR, but induced microvascular perfusion defects occur in a significant percentage of patients with coronary stenoses that do not have impaired fractional flow reserve.
- © 2011 by American Heart Association, Inc.