title: Importance of relative pulmonary hypertension in cardiac surgery: the mean systemic-to-pulmonary artery pressure ratio.
abstract: OBJECTIVE
  To determine the importance of the mean arterial pressure-to-mean pulmonary artery pressure ratio (MAP/MPAP) in cardiac surgical patients.
  
  
  METHODS
  Retrospective and prospective studies (3 groups).
  
  
  METHODS
  Tertiary care hospital.
  
  
  METHODS
  Cardiac surgical patients (1,557).
  
  
  METHODS
  Retrospective analysis (group 1), induction of general anesthesia (group 2), and transesophageal Doppler echocardiography (group 3).
  
  
  RESULTS
  In group 1 (n = 1,439), demographic, hemodynamic, and other perioperative variables were collected with follow-up until hospital discharge. The primary outcome was a composite index of hemodynamic complications that included death, resuscitated cardiac arrest, use of vasopressive drugs for >24 hours postoperatively, or the use of an intra-aortic balloon pump that was not present preoperatively. In group 2 (n = 34), the effect of general anesthesia on the MAP/MPAP ratio was studied, and Doppler echocardiography was used to evaluate diastolic profiles in group 3 (n = 74). In group 1, a total of 302 patients experienced hemodynamic complications (21%). The MAP/MPAP ratio was significantly lower in the patients who developed complications (3.3 +/- 1.3 v 4.0 +/- 1.4, p < 0.0001). Multiple stepwise logistic regression analysis showed the MAP/MPAP ratio to be an independent predictor of hemodynamic complications (p < 0.0001). In group 2, the induction of anesthesia decreased both MAP and MPAP, but the ratio remain unchanged (p = 0.242). In group 3, patients with moderate-to-severe diastolic dysfunction (DD) had a lower ratio (3.5 +/- 0.9 v 4.0 +/- 1.1 compared with those with normal-to-mild DD, p = 0.07).
  
  
  CONCLUSIONS
  The MAP/MPAP ratio is a useful hemodynamic variable in cardiac surgery. It can be used to predict hemodynamic complications after cardiac surgery, is not influenced by the induction of anesthesia, and tends to correlate with the severity of left ventricular diastolic profiles.
authors.affiliation: Department of Anesthesiology, Montreal Heart Institute, Montreal, Quebec, Canada.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Robitaille
authors.forename: André Y
authors.initials: AY
authors.lastname: Denault
authors.forename: Pierre
authors.initials: P
authors.lastname: Couture
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bélisle
authors.forename: Annik
authors.initials: A
authors.lastname: Fortier
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Guertin
authors.forename: Michel
authors.initials: M
authors.lastname: Carrier
authors.forename: Raymond
authors.initials: R
authors.lastname: Martineau
mesh_terms: D000368:Aged; D001794:Blood Pressure; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications* / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000503:physiopathology*; D012189:Retrospective Studies; D016277:Ventricular Function, Left