Does the degree of cyanosis affect myocardial adenosine triphosphate levels and function in children undergoing surgical procedures for congenital heart disease?

Objective: The outcome of children with cyanosis after cardiac surgical pro cedures is inferior to that of children who are acyanotic, Animal studies i ndicated detrimental effects of chronic hypoxia on myocardial metabolism an d function. We studied whether the presence or the degree of cyanosis adver sely affected myocardial adenosine triphosphate, ventricular function, and clinical outcome in children. Methods: Forty-eight children who underwent r epair of tetralogy of Fallot were divided according to their preoperative s aturation: group I, 90% to 100% (n = 14 patients); group II, 80% to 89% (n = 16 patients); and group III, 65% to 79% (n = 18 patients). Adenosine trip hosphate was measured from right ventricular biopsy specimens taken before ischemia, at 15 minutes of ischemia, at end-ischemia, and at 15 minutes of reperfusion, Ejection fraction was measured by echocardiography. Results: E ven before surgical ischemia, compared with groups I and II, group III had lower preoperative ejection fraction (59% +/- 2.9% vs 67% +/- 1.7% and 68% +/- 1.0%; P <.01) and lower preischemic adenosine triphosphate levels (15.1 +/- 2.1 vs 19.1 +/- 1.9 and 21.4 +/- 1.5 mu mol/g dry weight; P <.01). Aft er 15 minutes of ischemia, group III had lower adenosine triphosphate level s (11.2 +/- 1.8 vs 14.77 +/- 2.3 and 17.6 +/- 3.1 mu mol/g dry weight; P <. 01). With reperfusion, both cyanotic groups lost further adenosine triphosp hate compared with partial recovery in the acyanotic group (-22% +/- 3.8%, -20% +/- 3.1% vs +18% +/- 1.8% P < .01) Children in group III had a more co mplicated postoperative course as evidenced by longer ventilatory support ( 85 +/- 25 hours vs 31 +/- 15 and 40 +/- 21 hours; P =.07), inotropic suppor t (86 +/- 23 hours vs 38 +/- 12 and 36 +/- 4 hours; P <.01), and intensive care unit stay (160 +/- 35 hours vs 60 +/- 10 and 82 +/- 18 hours; P =.02). Conclusions: The degree of cyanosis adversely affects myocardial adenosine triphosphate, function, and clinical outcome of children who undergo cardi ac operation. Children with cyanosis should be identified as a higher risk group that could be targeted for supportive interventions.