title: Image-guided quantification of cardioplegia delivery during cardiac surgery.
abstract: BACKGROUND
  Homogenous distribution of cardioplegia delivered to the myocardium has been identified as an important predictor of post-cardiopulmonary bypass ventricular recovery and function. Presently, a method to determine adequate distribution of cardioplegia in patients during cardiac surgery does not exist. The goal of this study was to evaluate the feasibility of quantifying cardioplegia delivery using a novel, noninvasive optical method. Such a system would permit instantaneous imaging of jeopardized myocardium and allow immediate, intraoperative corrective measures.
  
  
  METHODS
  We have previously developed a portable, intraoperative near-infrared (NIR) fluorescence imaging system for use in large animal cardiac surgery that simultaneously displays color video and NIR fluorescent images of the surgical field. By introducing exogenous, NIR fluorophores, specific cardiac functions can be visualized in real-time.
  
  
  RESULTS
  In a porcine cardiopulmonary bypass model, we demonstrate that the FDA-approved intravascular fluorophore indocyanine green (ICG) permits real-time assessment of cardioplegia delivery. ICG was injected into an aortic root and/or transatrial coronary sinus catheter during delivery of crystalloid cardioplegia solution. Segmental distribution was immediately noted at the time of injection. In a subset of animals, simulated coronary occlusions resulted in imaging defects consistent with poor cardioplegia delivery and jeopardized myocardium. Videodensitometric analysis was performed on-line to quantify distribution to the right ventricle and left ventricle.
  
  
  CONCLUSIONS
  We report the development of a novel, noninvasive, intraoperative technique that can easily and safely provide a visual assessment of cardioplegia delivery (antegrade and/or retrograde) and that offers the potential to quantify the relative segmental distribution during cardiac surgical procedures.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Edward G
authors.initials: EG
authors.lastname: Soltesz
authors.forename: Rita G
authors.initials: RG
authors.lastname: Laurence
authors.forename: Alec M
authors.initials: AM
authors.lastname: De Grand
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Cohn
authors.forename: Tomislav
authors.initials: T
authors.lastname: Mihaljevic
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D002315:Cardiopulmonary Bypass / Q000379:methods*; D004396:Coloring Agents; D003952:Diagnostic Imaging / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005453:Fluorescence; D007208:Indocyanine Green; D007430:Intraoperative Care / Q000379:methods*; D008297:Male; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine
chemical_list: D002314:Cardioplegic Solutions; D004396:Coloring Agents; D007208:Indocyanine Green