title: Myocardial washout of sonicated iopamidol does not reflect the transmural distribution of coronary blood flow.
abstract: It has been shown in previous studies that myocardial contrast echocardiography provides quantitative information on coronary blood flow. However, the ability of contrast echo to assess the transmural (endo/epicardial) distribution of blood flow is still debated. To test this hypothesis, the left circumflex coronary arteries of six anaesthetized open-chested dogs were cannulated and perfused with blood from the femoral artery. At different rates of coronary blood flow, during adenosine-induced coronary vasodilation, sonicated iopamidol and radionuclide labelled microspheres were injected into the coronary cannula, immediately proximal to a mixing chamber. Two-D echo images were digitized and myocardial time-intensity curves were obtained for the endocardial, mid- and epicardial layers. A good correlation existed between contrast washout of the entire ventricular wall and coronary flow (r = 0.85). However, the washout rate from the endo-, mid- and epicardial layers showed weak correlations with corresponding regional blood flows measured by microspheres (r = 0.56, 0.71 and 0.58, respectively). No significant relationship was found between the endo/epicardial washout ratio and the corresponding flow ratio by microspheres. Thus, measurement of the transmural distribution of coronary blood flow by myocardial contrast echocardiography remains an elusive goal.
authors.affiliation: C.N.R., Clinical Physiology Institute, Pisa, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Rovai
authors.forename: G
authors.initials: G
authors.lastname: Ghelardini
authors.forename: M
authors.initials: M
authors.lastname: Lombardi
authors.forename: M G
authors.initials: MG
authors.lastname: Trivella
authors.forename: E
authors.initials: E
authors.lastname: Nevola
authors.forename: L
authors.initials: L
authors.lastname: Taddei
authors.forename: E M
authors.initials: EM
authors.lastname: Ferdeghini
authors.forename: A
authors.initials: A
authors.lastname: Distante
authors.forename: A
authors.initials: A
authors.lastname: L'Abbate
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D004285:Dogs; D004452:Echocardiography; D005260:Female; D007091:Image Processing, Computer-Assisted; D007479:Iopamidol / Q000493:pharmacokinetics*; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D013010:Sonication
chemical_list: D007479:Iopamidol