title: Multidose cold oxygenated blood is superior to a single dose of Bretschneider HTK-cardioplegia in the pig.
abstract: BACKGROUND
  A single-dose strategy for cardioplegia is desired in minimal invasive approaches to valve surgery and aortic arch repairs. We hypothesized that a single infusion of Bretschneider HTK solution offers myocardial protection comparable to repeated cold oxygenated blood.
  
  
  METHODS
  Sixteen pigs on bypass with 60 minutes of aortic cross-clamping were randomized to a single dose of Custodiol (HTK group) or repeated oxygenated blood cardioplegia (CBC group). Left ventricular function and perfusion were evaluated by conductance catheter, echocardiography, and microspheres. Myocardial injury was assessed with serum troponin-T.
  
  
  RESULTS
  Baseline values showed no group differences. One hour after declamping cardiac index was reduced in the HTK group, 3.5 +/- 0.2 L x min(-1) x m(-2) (mean +/- standard error of the mean) compared with 4.7 +/- 0.4 L x min(-1) x m(-2) in the CBC group (p < 0.0005), decreasing to 4.0 +/- 0.2 and 3.9 +/- 0.2 L x min(-1) x m(-2) after 2 and 3 hours, respectively (p < 0.005 versus 1 hour). In the HTK group cardiac index remained low and unchanged. In the CBC group preload recruitable stroke work was 72.6 +/- 1.2 mm Hg 1 hour after declamping, decreasing to 65.2 +/- 2.5 and 60.3 +/- 3.9 mm Hg after 2 and 3 hours, respectively (p < 0.05 versus 1 hour). In the HTK group corresponding values after 1, 2, and 3 hours were low at 47.2 +/- 4.4, 48.4 +/- 4.2, and 50.7 +/- 4.3 mm Hg, respectively (p < 0.025 versus CBC for all). Subendocardial radial peak systolic strain averaged 80.5% +/- 4.8% after declamping in the CBC group versus 53.4% +/- 5.5% in the HTK group (p = 0.002). Serum troponin-T release was lower in the CBC group.
  
  
  CONCLUSIONS
  Repeated oxygenated blood cardioplegia provides better myocardial protection and preservation of left ventricular function than a single dose of HTK during the early hours after declamping.
authors.affiliation: Surgical Research Laboratory, Department of Surgical Sciences, University of Bergen, Bergen, Norway. tfan@online.no
authors.forename: Tord
authors.initials: T
authors.lastname: Fannelop
authors.forename: Geir Olav
authors.initials: GO
authors.lastname: Dahle
authors.forename: Pirjo-Riitta
authors.initials: PR
authors.lastname: Salminen
authors.forename: Christian Arvei
authors.initials: CA
authors.lastname: Moen
authors.forename: Knut
authors.initials: K
authors.lastname: Matre
authors.forename: Arve
authors.initials: A
authors.lastname: Mongstad
authors.forename: Finn
authors.initials: F
authors.lastname: Eliassen
authors.forename: Leidulf
authors.initials: L
authors.lastname: Segadal
authors.forename: Ketil
authors.initials: K
authors.lastname: Grong