title: A "twilight period" of coronary perfusion: the risk of intraoperative infarction in surgery for main left coronary obstruction.
abstract: This study investigates the significance of an intraoperative period of low coronary perfusion pressure which may lead to ischemia, infarction, or both, in patients undergoing coronary bypass surgery for tight left main obstruction. "Twilight Period" (TP) was defined as the time interval from initiation of cardiopulmonary bypass to implementation of cold cardioplegia. Fifty-four patients with main left coronary obstruction (greater than 50%) were divided in three groups: Group I (20), TP less than 5 minutes; Group II (15), TP = 5-15 minutes; and Group III (19), TP greater than 15 minutes. Monitoring parameters included: systemic perfusion pressure during TP, perfusion flows, length of TP, time of ischemia, myocardial temperatures during ischemia, postoperative CK-MB level, EKG-detectable infarction, and postoperative therapeutic support requirements.
  
  
  RESULTS
  Intraoperative myocardial infarction by EKG was 0% in Group I, 7% in Group II, and 26.3% in Group III; mortality was 0%, 0%, and 15.7%, respectively. CK-MB values were 18 +/- 3.2 IU, Group I; 18.3 +/- 2.5 IU, Group II; and 49.4 +/- 10.3 IU, Group III. Group I vs. III: P 0.01. Levels of postoperative support: Level A, less than 12 hours; Level B, 12-36 hours; and Level C, greater than 36 hours. Intra-aortic balloon pump (IABP) was considered Level C. In Group I, 75% (15/20) fell in Level A; 15% (3/20) in Level B and 10% (2/20) in Level C. In Group II, 60% (9/15) fell in Level A; 26.7% (4/15) in Level B; and 13% (2/15) in Level C. In Group III, 36.8% (7/19) fell in Level A; 15.8% (3/19) in Level B; and 47.4% (9/19) in Level C.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Cardiovascular and Thoracic Surgery, University of Minnesota Hospital and Clinic, Minneapolis, Minnesota.
authors.forename: J E
authors.initials: JE
authors.lastname: Molina
mesh_terms: D001026:Coronary Artery Bypass / Q000379:methods; D003327:Coronary Disease / Q000150:complications / Q000601:surgery*; D003331:Coronary Vessels; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography; D006324:Heart Arrest, Induced / Q000379:methods; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D007527:Isoenzymes; D016343:Monitoring, Intraoperative; D009203:Myocardial Infarction / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D010477:Perfusion; D011183:Postoperative Complications / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D012307:Risk Factors; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase