title: The effect of epinephrine on coronary flow in the setting of a systemic-to-pulmonary artery shunt.
abstract: BACKGROUND
  Indirect clinical evidence suggests that coronary blood flow (CBF) is altered in patients palliated with systemic-to-pulmonary artery shunts (SPSs). The addition of epinephrine may exert additional effects.
  
  
  METHODS
  A total of 11 newborn piglets underwent placement of a 3.5- to 4-mm graft between the innominate artery and the pulmonary artery. Doppler probes measured flow continuously in the aorta (aortic flow [AoF]), pulmonary artery and left coronary artery at baseline (SPS closed), SPS open, and during epinephrine administration (SPS closed and open). Each animal served as its own control. Systolic and diastolic CBF, resistance (coronary vascular resistance index [CVRI]), and myocardial oxygen supply demand ratio were calculated.
  
  
  RESULTS
  Opening the SPS increased AoF and decreased systolic and diastolic pressure from baseline, with and without the presence of epinephrine. The CBF and CVRI decreased on opening the SPS in the presence of epinephrine. The decrease occurred only in diastole and was proportional to pulmonary-to-systemic flow ratio (Qp/Qs). Epinephrine infusion itself reduced CVRI with SPS closed, but there was little further decrease on opening SPS. Myocardial oxygen supply-demand ratio decreased on opening SPS at baseline and with epinephrine.
  
  
  CONCLUSIONS
  This study suggests that SPS decreases CBF, especially in the presence of a higher Qp/Qs and epinephrine. The mechanism is largely due to the decrease in diastolic pressure and the inability of the coronary arteries to compensate with vasodilation.
authors: Cardiothoracic Surgery, The Heart Center at Arnold Palmer Hospital for Children, Orlando, FL, USA.
authors: William M
authors: WM
authors: DeCampli
authors: Felix W
authors: FW
authors: Tsai
authors: I Ricardo
authors: IR
authors: Argueta-Morales
authors: Cathy
authors: C
authors: Smith
authors: Hamish M
authors: HM
authors: Munro
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods; D000818:Animals; D000831:Animals, Newborn; D016122:Brachiocephalic Trunk / Q000187:drug effects / Q000503:physiopathology / Q000601:surgery*; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D004837:Epinephrine / Q000494:pharmacology*; D006330:Heart Defects, Congenital / Q000503:physiopathology / Q000601:surgery*; D011651:Pulmonary Artery / Q000187:drug effects / Q000503:physiopathology / Q000601:surgery*; D011652:Pulmonary Circulation / Q000187:drug effects* / Q000502:physiology; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D004837:Epinephrine
keywords: animal model; circulatory hemodynamics; congenital heart surgery; coronary artery physiology; palliation; pediatric; shunt innominate-to-pulmonary artery