title: Transesophageal Echocardiography Guidance of Antegrade Cardioplegia Delivery for Cardiac Surgery.
abstract: OBJECTIVE
  The initial volume of antegrade cardioplegia used to induce asystole during aortic cross-clamp still is based on empiric methods and may be excessive, potentially leading to hyperkalemia, myocardial edema, and acute left ventricular distention from aortic regurgitation. The objectives were to determine whether the volume of cardioplegia required to induce asystole is proportional to left ventricular mass, and whether the degree of left ventricular distention is proportional to the severity of aortic regurgitation.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Two tertiary university hospitals.
  
  
  METHODS
  Transesophageal echocardiography was used to estimate left ventricular mass (prolate ellipse revolution formula), quantify aortic regurgitation, and monitor for distention during initial antegrade cardioplegia delivery. The volume of cardioplegia required for asystole was recorded.
  
  
  METHODS
  Fifty-eight patients aged over 18 years scheduled for cardiac surgery requiring aortic cross-clamping.
  
  
  RESULTS
  There was a weak correlation of left ventricular mass and antegrade cardioplegia volume required for asystole (r = 0.35, p = 0.047). The degree of left ventricular distention correlated moderately with the severity of aortic regurgitation (r = 0.55, p = 0.007) and was excessive and stopped early (aborted) in 24% of all patients, including 18% of 39 patients without aortic regurgitation. An aortic regurgitation vena contracta of 0.3 cm predicted aborted cardioplegia with modest accuracy (AUC 0.81, 0.66-0.99, p = 0.02, sensitivity 71%, specifity 81%).
  
  
  CONCLUSIONS
  Estimated left ventricular mass is not a useful predictor of the initial volume of antegrade cardioplegia required to induce asystole. However transesophageal echocardiography can predict and monitor for left ventricular distention, which is common.
authors.affiliation: Department of Surgery, Level 6 Center for Medical Research, University of Melbourne, Royal Parade, Parkville, Australia; Department of Anaesthesia and Perioperative Medicine; Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, Australia. Electronic address: dj_canty@hotmail.com.
authors.forename: David J
authors.initials: DJ
authors.lastname: Canty
authors.affiliation: Department of Surgery and Department of Cardiothoracic Surgery, Monash Medical Center, Clayton, Australia.
authors.forename: Prashant
authors.initials: P
authors.lastname: Joshi
authors.affiliation: Department of Surgery, Level 6 Center for Medical Research, University of Melbourne, Royal Parade, Parkville, Australia; Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, Australia.
authors.forename: Colin F
authors.initials: CF
authors.lastname: Royse
authors.affiliation: Perfusion Services, Unit 2, Tulip Street, Cheltenham, Australia.
authors.forename: James
authors.initials: J
authors.lastname: McMillan
authors.affiliation: Perfusion Services, Unit 2, Tulip Street, Cheltenham, Australia.
authors.forename: Sara
authors.initials: S
authors.lastname: Tayeh
authors.affiliation: Department of Surgery, Level 6 Center for Medical Research, University of Melbourne, Royal Parade, Parkville, Australia; Department of Surgery and Department of Cardiothoracic Surgery, Monash Medical Center, Clayton, Australia.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Smith
mesh_terms: D000368:Aged; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000601:surgery; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D016503:Drug Delivery Systems / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D002314:Cardioplegic Solutions
keywords: aortic valve insufficiency; cardiac arrest; cardiac surgery; cardioplegia; transesophageal echocardiography