Controlled reoxygenation during cardiopulmonary bypass decreases markers of organ damage, inflammation, and oxidative stress in single-ventricle patients undergoing pediatric heart surgery.

OBJECTIVE: Single-ventricle patients undergoing pediatric heart surgery are a high-risk group owing to reoxygenation injury during cardiopulmonary bypass (CPB). The present study investigated the effects of controlled reoxygenation CPB on biomarkers of organ damage, inflammation, stress, and long-term functional outcomes in cyanotic patients with either a single or double ventricle during open heart surgery. METHODS: Cyanotic patients with either a single (n = 32) or double (n = 47) ventricle undergoing surgical correction were randomized to receive CPB using either standard oxygen levels or controlled reoxygenation. The markers of cardiac injury, inflammation, stress, and cerebral and hepatic injury were measured preoperatively, at 10 and 30 minutes after starting CPB, and at 10 minutes and 4 and 24 hours after CPB. The data were analyzed using a mixed regression model. RESULTS: No difference was found in the pre- or intraoperative characteristics between the standard and controlled reoxygenation CPB groups for single- or double-ventricle patients. In the single-ventricle patients, controlled reoxygenation CPB significantly (P < .05) decreased the markers of organ damage, inflammation, stress, and oxidative stress. In contrast, the markers of inflammation and cardiac injury were not altered by controlled reoxygenation CPB in the double-ventricle patients. CONCLUSIONS: Controlled reoxygenation CPB decreased the markers of organ damage, stress, inflammation, and oxidative stress in single-ventricle patients undergoing cardiac surgery.

Retrograde hot-shot cardioplegia in patients with left ventricular hypertrophy undergoing aortic valve replacement.

BACKGROUND: Intermittent antegrade cold-blood cardioplegia followed by terminal warm-blood cardioplegic reperfusion or hot-shot is reported to reduce myocardial injury in the setting of coronary surgery. The efficacy of this cardioplegic technique in patients with left ventricular hypertrophy secondary to aortic stenosis remains uncertain. METHODS: Thirty-six patients with left ventricular hypertrophy undergoing aortic valve replacement were prospectively randomized to cold-blood cardioplegia either alone (cold-blood cardioplegia group) or with retrograde hot-shot (hot-shot group). Reperfusion injury was assessed by measuring myocardial levels of adenosine triphosphate and lactate in left and right ventricular biopsies taken 5 minutes after institution of cardiopulmonary bypass and 20 minutes after removal of cross-clamp using high-performance liquid chromatography and enzymatic techniques. Myocardial injury was assessed by serial release of troponin I up to 48 hours postoperatively. Overall clinical outcome was prospectively collected. RESULTS: Baseline and intraoperative characteristics were similar between groups. In the hot-shot group, there were no significant changes in the myocardial concentration of adenosine triphosphate and lactate in both left and right ventricular biopsies after reperfusion. In the cold-blood cardioplegia group, there was a trend to a fall in adenosine triphosphate levels in the left and right ventricular biopsies after reperfusion, but this reached statistical significance only in the right ventricle. Troponin I release was raised in both groups at 4 and 12 hours after surgery (p < 0.05), but did not reach levels of myocardial infarction. CONCLUSIONS: The terminal retrograde hot-shot reperfusion does not add any extra benefit to antegrade cold-blood cardioplegia in preventing myocardial injury in patients with left ventricular hypertrophy undergoing aortic valve replacement. Nevertheless, it appears to reduce ischemic stress in the right ventricle. There was no difference in clinical outcome between groups.

Changes in myocardial free amino acids during pediatric cardiac surgery: a randomised controlled trial of three cardioplegic techniques.

OBJECTIVE: The developing heart has a much greater dependence on amino acid (AA) metabolism than the adult heart in determining its ischemic tolerance. Blood cardioplegia preserves myocardial free AAs in adult hearts but no clinical studies have looked at the effect of different cardioplegic techniques on intracellular free AAs in the pediatric heart. METHODS: Pediatric patients were randomised to receive intermittent antegrade cold crystalloid (CC), cold blood (CB) or cold blood cardioplegia with a 'hot shot' (CB+HS). Right ventricular biopsies were collected prior to ischemia, at the end of ischemia and 20 min after reperfusion. Amino acid levels were analysed as repeated measures, adjusting for baseline levels. Data were analysed separately for acyanotic and cyanotic patients. RESULTS: Of 103 patients recruited, 32 (22 acyanotic and 10 cyanotic), 36 (24/12) and 35 (25/10), respectively were allocated to CC, CB and CB+HS groups. Cyanotic patients were significantly younger with longer cross-clamp times. In acyanotic patients, there were no significant effects of cardioplegic method on aspartate, glutamine, taurine, alanine or branched chain AA levels (all p>0.05). However, in cyanotic patients, there were significant interactions of cardioplegic method and time (all p<0.05) for all amino acids, with patients allocated to CB+HS having higher levels after reperfusion compared with CC, and patients allocated to CB having intermediate levels. CONCLUSIONS: For cyanotic patients (younger, longer cross-clamp times), CB+HS preserves myocardial free AAs better than CC; CB gives an intermediate effect. In acyanotic patients, AA levels (all p>0.15) and group means were similar both at the end of ischemia and after reperfusion.