title: Superior mesenteric artery blood flow modifications during off-pump coronary surgery.
abstract: BACKGROUND
  Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography.
  
  
  METHODS
  In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery).
  
  
  RESULTS
  Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery.
  
  
  CONCLUSIONS
  Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.
authors.affiliation: Dipartimento dell'Emergenza e Trapianti d'Organo, Azienda Ospedaliero-Universitaria Policlinico, Bari, Italy. pinofiore@yahoo.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Fiore
authors.forename: Nicola
authors.initials: N
authors.lastname: Brienza
authors.forename: Pasquale
authors.initials: P
authors.lastname: Cicala
authors.forename: Pasquale
authors.initials: P
authors.lastname: Tunzi
authors.forename: Nicola
authors.initials: N
authors.lastname: Marraudino
authors.forename: Luigi de Luca Tupputi
authors.initials: Lde L
authors.lastname: Schinosa
authors.forename: Tommaso
authors.initials: T
authors.lastname: Fiore
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output; D047549:Coronary Artery Bypass, Off-Pump; D017548:Echocardiography, Transesophageal; D017558:Elective Surgical Procedures; D005260:Female; D041981:Gastrointestinal Tract / Q000098:blood supply; D018056:Hemorheology; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D007431:Intraoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D007432:Intraoperative Period; D007511:Ischemia / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011446:Prospective Studies; D013152:Splanchnic Circulation