title: Noninvasive assessment of myocardial bridging by coronary flow velocity reserve with transthoracic Doppler echocardiography: vasodilator vs. inotropic stimulation.
abstract: BACKGROUND
  To consider hemodynamic assessment of myocardial bridging (MB) adequate, it is believed that inotropic stimulation with dobutamine should be estimated because its dynamic nature depends on the degree of extravascular coronary compression. This study evaluated comparative assessment of hemodynamic relevance of MB using coronary flow velocity reserve (CFVR) measurements by transthoracic Doppler echocardiography (TTDE) with vasodilatative and inotropic challenges.
  
  
  METHODS
  This prospective study included forty-four patients with angiographic evidence of isolated MB of the left anterior descending coronary artery (LAD) and systolic compression of ≥50% diameter stenosis. All patients were evaluated by exercise stress-echocardiography (ExSE) test for signs of myocardial ischemia, and CFVR of the distal segment of LAD during iv.infusion of adenosine (ADO:140μg/kg/min) and iv.infusion of dobutamine (DOB:10-40μg/kg/min), separately.
  
  
  RESULTS
  Exercise-SE was positive for myocardial ischemia in 8/44 (18%) of patients. CFVR during ADO was significantly higher than CFVR during peak DOB (2.85±0.68 vs. 2.44±0.48, p=0.002). CFVR during peak DOB was significantly lower in SE-positive group in comparison to SE-negative group (2.01±0.16 vs. 2.54±0.47, p<0.001), but not for ADO (2.47±0.51 vs. 2.89±0.70, p=0.168), respectively. Multivariable logistic analysis showed that CFVR peak DOB was the most significant predictor of functional significant MB (OR 0.011, 95%CI: 0.001-0.507, p=0.021). Receiver-operating characteristic curves have shown that TTDE-CFVR obtained by high-dose of dobutamine infusion is better than those by adenosine regarding to functional status of MB (AUC 0.861, p=0.004; AUC 0.674, p=0.179, respectively).
  
  
  CONCLUSIONS
  Non-invasive CFVR measurement by TTDE during inotropic stimulation, in comparison to vasodilation, provides more reliable functional evaluation of MB.
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia. Electronic address: srdjanaleksandric@gmail.com.
authors.forename: Srdjan
authors.initials: S
authors.lastname: Aleksandric
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Ana
authors.initials: A
authors.lastname: Djordjevic-Dikic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Branko
authors.initials: B
authors.lastname: Beleslin
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Biljana
authors.initials: B
authors.lastname: Parapid
authors.affiliation: University of Belgrade, School of Medicine, Belgrade, Serbia; Institute of Anatomy "Niko Miljanic".
authors.forename: Gordana
authors.initials: G
authors.lastname: Teofilovski-Parapid
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Stepanovic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Dragan
authors.initials: D
authors.lastname: Simic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Nedeljkovic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Milan
authors.initials: M
authors.lastname: Petrovic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Milan
authors.initials: M
authors.lastname: Dobric
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Kragujevac, School of Medicine, Kragujevac, Serbia.
authors.forename: Miloje
authors.initials: M
authors.lastname: Tomasevic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Marko
authors.initials: M
authors.lastname: Banovic
authors.affiliation: Division of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; University of Belgrade, School of Medicine, Belgrade, Serbia.
authors.forename: Milan
authors.initials: M
authors.lastname: Nedeljkovic
authors.affiliation: University of Belgrade, School of Medicine, Belgrade, Serbia; Serbian Academy of Sciences and Arts, Belgrade, Serbia.
authors.forename: Miodrag
authors.initials: M
authors.lastname: Ostojic
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D061605:Administration, Intravenous; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects* / Q000502:physiology; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D004280:Dobutamine / Q000008:administration & dosage; D015150:Echocardiography, Doppler / Q000379:methods*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054084:Myocardial Bridging / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D011446:Prospective Studies; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D002316:Cardiotonic Agents; D014665:Vasodilator Agents; D004280:Dobutamine; D000241:Adenosine
keywords: Coronary flow velocity reserve; Dobutamine; Myocardial bridging; Myocardial ischemia; Stress-echocardiography; Transthoracic Doppler echocardiography