Continuous cold blood cardioplegia improves myocardial protection: a prospective randomized study.
BACKGROUND
To assess the influence on myocardial protection of the rate of infusion (continuous vs intermittent) of cold blood cardioplegia administered retrogradely during prolonged aortic cross-clamping. The end-points were ventricular performance and biochemical markers of ischemia.


METHODS
Seventy patients undergoing myocardial revascularization for three-vessel disease were prospectively randomized to receive intermittent or continuous retrograde cold blood cardioplegia. Hemodynamic measurements were obtained using a rapid-response thermodilution catheter and included right ventricular ejection fraction, cardiac output, left and right ventricular stroke work index, and systemic and pulmonary vascular resistance. Blood samples were obtained from the coronary sinus before cross-clamp application and immediately after cross-clamp removal for determinations of lactate and hypoxanthine.


RESULTS
The left ventricular stroke work index trend was significantly superior (p = 0.038) by repeated-measures analysis in continuous cardioplegia. Other hemodynamic measurements revealed a similar trend. The need for postoperative inotropic drugs support was reduced in continuous cardioplegia. The release of lactate in the coronary sinus after unclamping was 2.30 +/- 0.12 mmol/L after intermittent cardioplegia and 1.97 +/- 0.09 mmol/L after continuous cardioplegia (p = 0.036). The release of hypoxanthine was 20.47 +/- 2.74 micromol/L in intermittent cardioplegia and 11.77 +/- 0.69 micromol/L in continuous cardioplegia (p = 0.002).


CONCLUSIONS
Continuous cold blood cardioplegia results in improved ventricular performance and reduced myocardial ischemia in comparison with intermittent administration.
Louagie
Yves A G
YA
Cardiovascular and Thoracic Unit, University Clinics of Mont Godinne, Université Catholique de Louvain, Mont Yvoir, Belgium. lougie@chir.ucl.ac.be
Jamart
Jacques
J
Gonzalez
Manuel
M
Collard
Edith
E
Broka
Serge
S
Galanti
Laurence
L
Gruslin
André
A
D000368:Aged; D002315:Cardiopulmonary Bypass; D003327:Coronary Disease / Q000503:physiopathology / Q000601:surgery*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D009204:Myocardial Revascularization; D010043:Outcome and Process Assessment, Health Care; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000502:physiology
D019344:Lactic Acid