title: Ventricular effluent of retrograde cardioplegia in human hearts has traversed capillary beds.
abstract: BACKGROUND
  In human hearts, as much as two thirds of retrograde cardioplegia is shunted through thebesian and arteriosinusoidal channels into the ventricular cavities. This ventricular effluent is believed to have bypassed the myocardial capillary beds and is therefore considered nonnutritive.
  
  
  METHODS
  To test this hypothesis, we studied the explanted hearts from 9 cardiac transplant recipients with the diagnosis of idiopathic cardiomyopathy. These hearts were arrested in situ with cold blood cardioplegia and excised with the coronary sinus intact. The left and right coronary ostia and the coronary sinus then were cannulated. Colored microspheres (15 +/- 5 microns) mixed in 37 degrees C blood cardioplegia were administered through the coronary sinus at a pressure of 30 to 40 mm Hg. Effluents from the coronary arteries and ventricular chambers were collected and analyzed for microsphere concentration.
  
  
  RESULTS
  Approximately 80% of retrograde cardioplegia solution was recovered in the ventricular chambers. Nearly 40% of this ventricular chambers effluent had traversed capillary beds and, thus, we believe has nutritive properties. Almost all of the coronary artery effluent of retrograde cardioplegia solution had traversed capillary beds. The total nutritive fraction of retrograde warm blood cardioplegia in this explanted human heart model was approximately 55%.
  
  
  CONCLUSIONS
  These findings suggest that the ventricular chamber effluent of retrograde blood cardioplegia contributes to the metabolic homeostasis of the arrested human heart.
authors.affiliation: Department of Surgery, University of California, Los Angeles, Medical Center 90024, USA.
authors.forename: A
authors.initials: A
authors.lastname: Ardehali
authors.forename: H
authors.initials: H
authors.lastname: Laks
authors.forename: D C
authors.initials: DC
authors.lastname: Drinkwater
authors.forename: R N
authors.initials: RN
authors.lastname: Gates
authors.forename: E
authors.initials: E
authors.lastname: Kaczer
mesh_terms: D002196:Capillaries / Q000378:metabolism; D002314:Cardioplegic Solutions / Q000493:pharmacokinetics*; D003326:Coronary Circulation; D006324:Heart Arrest, Induced; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008863:Microspheres; D009206:Myocardium / Q000378:metabolism*
chemical_list: D002314:Cardioplegic Solutions