title: Comparison of Fractional Flow Reserve Assessment With Demand Stress Myocardial Contrast Echocardiography in Angiographically Intermediate Coronary Stenoses.
abstract: 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.
  
  
  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 a significant percentage of intermediate stenoses with normal FFR values, CBF during demand stress is reduced, resulting in myocardial ischemia.
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: Juefei
authors: J
authors: Wu
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: David
authors: D
authors: Barton
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: Feng
authors: F
authors: Xie
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: Edward
authors: E
authors: O'Leary
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: John
authors: J
authors: Steuter
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.).
authors: Gregory
authors: G
authors: Pavlides
authors: From the Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (J.W.); Department of Cardiology, Internal Medicine, University of Nebraska Medical Center, Omaha (D.B., F.X., E.O'L., G.P., T.R.P.); and Nebraska Heart, Lincoln (J.S.). trporter@unmc.edu.
authors: Thomas R
authors: TR
authors: Porter
mesh_terms: D058665:Adrenergic beta-1 Receptor Agonists / Q000008:administration & dosage; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004280:Dobutamine / Q000008:administration & dosage; D025401:Echocardiography, Stress; D005080:Exercise Test; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D058665:Adrenergic beta-1 Receptor Agonists; D003287:Contrast Media; D004280:Dobutamine
keywords: coronary angiography; coronary artery disease; dobutamine; myocardial ischemia; perfusion imaging