title: Coronary wave energy: a novel predictor of functional recovery after myocardial infarction.
abstract: BACKGROUND
  Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery.
  
  
  RESULTS
  Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (r=-0.81; P<0.0001) and strongly predicted regional left ventricular recovery (r=0.68; P=0.001). By receiver operating characteristic analysis, a backward-traveling (microcirculatory) expansion wave threshold of 2.8 W m(-2) s(-2)×10(5) predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (r=0.48; P=0.03) but not left ventricular recovery (r=-0.34; P=0.07).
  
  
  CONCLUSIONS
  The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas' National Health Service Foundation Trust, Cardiovascular Division, London, United Kingdom.
authors.forename: Kalpa
authors.initials: K
authors.lastname: De Silva
authors.forename: Paul
authors.initials: P
authors.lastname: Foster
authors.forename: Antoine
authors.initials: A
authors.lastname: Guilcher
authors.forename: Asela
authors.initials: A
authors.lastname: Bandara
authors.forename: Roy
authors.initials: R
authors.lastname: Jogiya
authors.forename: Tim
authors.initials: T
authors.lastname: Lockie
authors.forename: Phil
authors.initials: P
authors.lastname: Chowiencyzk
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.forename: Michael
authors.initials: M
authors.lastname: Marber
authors.forename: Simon
authors.initials: S
authors.lastname: Redwood
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
authors.forename: Divaka
authors.initials: D
authors.lastname: Perera
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D006328:Cardiac Catheterization / Q000379:methods* / Q000706:statistics & numerical data; D003326:Coronary Circulation / Q000502:physiology*; D005260:Female; D005682:Gadolinium; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D015588:Observer Variation; D062645:Percutaneous Coronary Intervention; D011237:Predictive Value of Tests; D011379:Prognosis; D020127:Recovery of Function / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology; D020257:Ventricular Remodeling / Q000502:physiology
chemical_list: D005682:Gadolinium