Acute right ventricular restrictive physiology after repair of tetralogy of fallot - Association with myocardial injury and oxidative stress

Background-Acute right ventricular (RV) restrictive physiology after tetralogy of Fallot: repair results in low cardiac output and a prolonged stay in the intensive care unit (ICU). However, its mechanism remains uncertain. Methods and Results-In the first 24 hours after tetralogy of Fallot repair (n=11 patients), serial prospective measurements were performed of cardiac troponin T, indexes of NO production (NO2- and NO3- combined as NOx), and iron metabolism and antioxidants. RV diastolic function was assessed by transthoracic Doppler echocardiography. Patients who had a long stay in the ICU were characterized by restrictive RV physiology (nonrestrictive group [n=7]: 3.0+/-0.6 days [mean+/-SD]; restrictive group [n=4]:10.7+/-3.1 days). Troponin T peak concentration and the area under its concentration-time curve (AUC) were higher in the restrictive RV group (peak: restrictive group 17.0+/-2.8 mu g/L, nonrestrictive group 10.4+/-4.6 mu g/L, P<0.03; AUG: restrictive group 268.8+/-73.6 mu g . h(-1). L-1, nonrestrictive group 136.2+/-48.3 mu g . h(-1).L-1, P<0.03). Plasma NOx/creatinine concentrations were higher in the restrictive group than the nonrestrictive group at 2 hours after bypass (restrictive group 1.3+/-0.4, nonrestrictive group 0.8+/-0.2; P=0.04) but were similar by 24 hours. Iron loading peaked 2 to 10 hours after bypass and was more severe in the restrictive group (peak transferrin saturation: restrictive group 83.9+/-13.0%, nonrestrictive group 58.3+/-16.2%, P=0.05; minimum-total iron-binding capacity: restrictive group 0.59+/-0.21%, nonrestrictive group 0.76+/-0.06%, P=0.04; minimum iron-binding antioxidant activity to oxyorganic radicals: restrictive group 9.5+/-22.4%, nonrestrictive group 50.6+/-11.4%, P=0.01). Conclusions-After tetralogy of Fallot repair, acute restrictive RV physiology is associated with greater intraoperative myocardial injury and postoperative oxidative stress with severe iron loading of transferrin.