RESTING CORONARY FLOW AND CORONARY FLOW RESERVE IN HUMAN INFANTS AFTER REPAIR OR PALLIATION OF CONGENITAL HEART-DEFECTS AS MEASURED BY POSITRON-EMISSION-TOMOGRAPHY

Objective: Coronary physiology in infants with congenital heart diseas e remains unclear, Our objective was to better understand coronary phy siology in infants with congenital heart disease, Methods: We used pos itron emission tomography with nitrogen 13-labeled ammonia to measure myocardial perfusion at rest and with adenosine (142 mu g/kg/min x 6 m inutes) in five infants after anatomic repair of a congenital heart le sion (group I), and in five infants after Norwood palliation for hypop lastic left heart syndrome (group II), The groups were matched for age , weight, and time from the operation, Results: Resting coronary flow in the left ventricle in group I was 1.8 +/- 0.2 ml/min/gm; resting ho w in the right ventricle in group II was 1.0 +/- 0.3 ml/min/gm (p = 0. 003), Coronary flow with adenosine was 2.6 +/- 0.5 ml/min/gm in group I and 1.5 +/- 0.7 ml/min/gm in group II (p = 0.02), Absolute coronary flow reserve was the same in both groups (1.5 +/- 0.2 in group I vs 1. 6 +/- 0.3 in group II, p = 0.45), Oxygen delivery was reduced in group II compared with group I at rest (16.1 +/- 4.2 ml/min/100 gm vs 28.9 +/- 4.42 ml/min/100 gm, p = 0.02) and with adenosine (25.5 +/- 8.1 ml/ min/100 gm vs 42.3 +/- 5.8 ml/min/100 gm, p = 0.02). Conclusions: Infa nts with repaired heart disease have higher resting flow and less coro nary flow reserve than previously reported for adults, After Norwood p alliation, infants have less perfusion and oxygen delivery to the syst emic ventricle than do infants with a repaired lesion, This may in par t explain why the outcome far patients with Norwood palliation is less favorable than for others.