Comparison of Fractional Flow Reserve Assessment With Demand Stress Myocardial Contrast Echocardiography in Angiographically Intermediate Coronary Stenoses

Abstract

Intracoronary pressure-derived fractional flow reserve (FFR) provides physiologically relevant information in determining the functional significance of a coronary stenosis, but provides no data regarding CBF. 6,11,12 An FFR-guided approach for revascularization is associated with improved clinical outcomes in multivessel CAD, 6 and abnormal values with this technique clearly identify a higher risk subgroup of patients. Although they do not seem to benefit from Background-Real-time myocardial contrast echocardiography (RTMCE) directly measures capillary flow (CBF), which in turn is a major regulator of coronary flow and resistance during demand or hyperemic stress. Although fractional flow reserve (FFR) was developed to assess the physiological relevance of an epicardial stenosis, it assumes maximal microvascular vasodilation and minimal resistance during vasodilator stress. Therefore, we sought to determine the relationship between CBF assessed with RTMCE during stress echocardiography and FFR in intermediate coronary lesions. Methods and Results-Sixty-seven vessels with 50% to 80% diameter stenoses by quantitative coronary angiography in 58 consecutive patients were examined with FFR and RTMCE (mean age, 60±13 years). RTMCE was performed using an incremental dobutamine (n=32) or exercise (n=26) stress protocol, and myocardial perfusion was assessed using a continuous infusion of ultrasound contrast. The presence or absence of inducible perfusion defects and wall motion abnormalities were correlated with FFR. Mean percent diameter stenosis was 60±9%. Eighteen stenoses (27%) had an FFR ≤ 0.8. Although 17 of the 18 stenoses that were FFR+ had abnormal CBF during RTMCE, 28 of the 49 stenoses (57%) that were FFR had abnormal CBF, and 24 (49%) had abnormal wall motion in the corresponding coronary artery territory during stress echocardiography. Conclusions-In

Clinical Quantification of Myocardial Blood Flow Using PET: Joint Position Paper of the SNMMI Cardiovascular Council and the ASNC

“…Importantly, for assessments of coronary physiology during cardiac catheterization, FFR and CFR can now be measured simultaneously with combined pressure sensor-and flow sensor-tipped guidewires. 204 More recently, quantitative estimates of myocardial perfusion from Doppler echocardiography 205,206 and contrast echocardiography 207 have emerged as having clinical value.…”

Myocardial Contrast Stress Echo Versus Fractional Flow Reserve

“…In this issue of Circulation: Cardiovascular Imaging, Wu et al 5 compared RTMCE CBF (ie, capillary) and left ventricular wall motion abnormality (LVWMA) to FFR in 58 patients with 67 intermediate coronary stenosis, ranging in severity from 50% to 80%. Dobutamine (n=32) or exercise (n=26) stress was performed before angiography.…”

“…However, 28 of 49 FFR-negative stenoses (57%) also had abnormal CBF and 24 of 49 (49%) had abnormal wall motion. Wu et al 5 concluded that a large percentage of intermediate stenoses with nonischemic FFR values (ie,>0.80) had reduced MCE CBF during demand stress, resulting in myocardial ischemia. Thus, abnormal CBF during demand stress RTMCE had high sensitivity (94%) for detecting a hemodynamically significant epicardial stenosis (ie, abnormal FFR) but a low specificity (57% for nonischemic FFR).…”

“…Factors influencing either volume or velocity can produce variations in CBF results. Although MCE does have the potential for quantification of blood flow, Wu et al 5 defined it in a binary fashion. An abnormal CBF during stress imaging was defined as a delay in subendocardial or transmural myocardial contrast replenishment of >2 s after a high mechanical index impulse that was in 2 contiguous segments, and which exhibited normal replenishment under resting conditions.…”

Echokardiographie

“…Weitere Fortschritte leistete die kardiale MRT-Diagnostik, die heute zum Standardverfahren avancierte aufgrund der fehlenden Strahlenbelastung, aber auch methodischer Fortschritte. Die Kontrastechokardiographie erlebte ebenfalls einen Innovationsschub, als das "highpower imaging" eingeführt wurde, welches die Mikrokavitationen zerstört [36][37][38][39][40][41][42][43]. In der Folge wird die Wiederanfärbung des Myokards beurteilt, um eine Abschätzung von Perfusionsstörun-gen zu erreichen.…”