Clinical evaluation of oxidative stress and myocardial reperfusion injury in pediatric cardiac surgery.

BACKGROUND: To evaluate oxidative stress and myocardial damage after aortic crossclamping release (ACCR) during cardio pulmonary bypass (CPB) in children two parameters were investigated: total glutathione (GSH) and its oxidoreductive reactions (GSH/GSSG) as expression of oxidative stress, and plasmatic turnover of myocardial taurine (TAU) as expression of cell damage. METHODS: The study was divided in two periods: 1) first period: analysis of oxidative stress and myocardial damage in 18 children. 2) Second period: evaluation of myocardial cell protection by controlled anterograde low oxygen warm reperfusion (ALOWR) before declamping. Twenty-one children were divided in two groups: not receiving (Group 1, 9 patients) and receiving (Group 2, 12 patients) ALOWR. RESULTS: In the first period GSH values increased significantly after onset of mechanical ventilation (MV) in vein, after CPB start in artery and after ACCR in coronary sinus. Moreover TAU turnover in aortic and coronary sinus blood increased significantly after ACCR. In the second period, Group 2 showed a lower oxidative stress after ACCR, while no differences were observed in TAU turnover. CONCLUSIONS: 1) Assessment of TAU and GSH levels can be considered a good method to clinically evaluate myocardial injury during cardiac surgery. 2) MV and CPB can induce oxidative stress before aortic clamping and can decrease the physiologic scavengers. Therefore, to prevent that depletion, the strategy of these techniques must be adapted to the patient and to his cardiac disease. 3) Intramyocardial TAU turnover is not significantly modified by the reperfusion technique. 4) ALOWR can reduce myocardial oxidative stress and can improve heart recovery after the cardioplegic arrest.

[Circulation support in left thoracotomy for descending thoracic aorta diseases in pediatric patients]. / L'assistenza circolatoria in toracotomia sinistra nella patologia dell'aorta toracica discendente nel paziente pediatrico.

BACKGROUND: Complications of surgery of the descending thoracic aorta could include neurological problems such as paraparesis and paraplegia. Intestinal ischemia and acute renal failure could occur, too. During the cross-clamping time, the perfusion of the distal aorta by means of extracorporeal circulatory assistance can be useful to protect the spinal cord and the splanchnic organs and to reduce the incidence of these untoward events. The aim of this study was to verify the efficacy and suitability of this type of circulatory assistance in a pediatric age group. METHODS: From January 1996 to March 2000, in the Pediatric Cardiac Surgery Department of the Gaslini Institute (Genoa, Italy), 6 patients (mean age 39 months, mean weight 14.4 kg) were treated using extracorporeal circulatory assistance through the left thoracotomy. Indications for surgery included the removal of a migrated device previously inserted in order to close a patent ductus arteriosus in 1 patient, recurrent coarctation in 2 patients, and native coarctation with a poor collateral circulation in 3 patients. RESULTS: The early and late mortality rates as well as the morbidity rates (both neurological and splanchnic) were nil. CONCLUSIONS: Extracorporeal circulatory assistance can be helpful in pediatric patients and it can prevent neurological and renal injuries in cases of a) coarctation of the aorta with a poor collateral circulation and low distal pressure (< 40 mmHg during aortic occlusion); b) recoarctation with complex anatomy; c) other pathologies requiring prolonged descending thoracic aorta cross-clamping.

[Closure of patent ductus arteriosus in thoracoscopy: analysis of the experience in the Gaslini Institute of Genoa]. / Chiusura del dotto arterioso persistente in toracoscopia: analisi dell'esperienza dell'istituto Gaslini di Genova.

In 1993, Laborde et al described a new surgical approach for closure of the patent ductus arteriosus (PDA), using a videoassisted technique. For the first time, videosurgery was utilized in pediatric cardiovascular surgery. The advantages of this new method are that it is minimally invasive (thoracotomy is replaced by three small holes), it reduces postoperative pain, recovery is more rapid with a shorter hospital stay and convalescence, and last but not least, it offers better aesthetic results. Between July 1994 and June 1996, we utilized the videoassisted thoracoscopic technique described by Laborde in 23 patients with PDA (age: 8 m-12 yrs, mean 45.2 m +/- 37.8; weight: 5.3-32 kg, mean 23 kg +/- 10.3). In two patients, we converted the procedure to standard thoracotomy due to anatomic problems. Echo-doppler evaluation, performed in the operating room shortly after the procedure, confirmed the complete closure of the PDA in all patients. There was neither morbidity nor mortality. The average hospital stay was four days. At a mean follow-up interval of 7.2 months (range 1-13 months), all patients showed excellent cosmetic results. We conclude that thoracoscopic closure of PDA is a valuable therapeutic option that can be used as an alternative to open-chest surgery and interventional cardiology.

[Differential types of pulmonary flow in bidirectional cavo-pulmonary anastomosis with an additional flow source]. / Differenti tipi di flusso polmonare nell'anastomosi cavo-polmonare bidirezionale con sorgente addizionale di flusso.

While Fontan operation is considered a palliative procedure for the treatment of complex congenital heart disease, its morbidity and mortality are certainly not negligible, especially in high-risk patients. In our opinion, a bidirectional cavo-pulmonary anastomosis with an additional source of blood flow to the lungs (Blalock-Taussig shunt, pulmonary artery banding, native pulmonary stenosis) represents a valuable surgical option in this subset of patients. From November 1992 to September 1994, sixteen patients with complex congenital heart disease underwent bidirectional cavo-pulmonary anastomosis, leaving an additional source of blood flow in place (modified Blalock-Taussig shunt in 9 cases, pulmonary artery banding in 6 cases, native pulmonary stenosis in 1 case). Eight of these patients (50%) were reinvestigated after a mean follow-up of 15.7 months (range 1-26 m). It has been possible to differentiate two types of pulmonary blood flow, according to the nature of the additional flow source; in the case of cavo-pulmonary anastomosis and pulmonary artery banding or pulmonary stenosis, pulmonary blood flow was pulsatile and evenly distributed to both lungs, while in the case of bidirectional cavo-pulmonary anastomosis and Blalock-Taussig shunt, pulmonary flow was non pulsatile and asymmetric (angiographic criteria). There were no hospital deaths. Late mortality was 12.5% (2 pts) due to worsening of atrioventricular valve regurgitation. In one of these two patients, prolonged pleural and pericardial effusion occurred. In conclusion, bidirectional cavo-pulmonary anastomosis with an additional flow source is a good alternative to classic or fenestrated Fontan operation in the treatment of complex congenital heart disease. The best results are obtained with an additional flow source represented by pulmonary artery banding or pulmonary stenosis, due to pulsatility and uniform distribution of blood flow in the pulmonary district. Morbility and mortality compare favorably with the rates observed in classic or fenestrated Fontan operation.

Bidirectional cavo-pulmonary anastomosis with an additional flow source to the lungs: clinical experience in 21 cases.

The Fontan operation is considered a palliative procedure for the treatment of complex congenital heart diseases with a morbidity and mortality that are not negligible, especially in high-risk patients. In these cases, a bidirectional cavopulmonary anastomosis with additional source of blood flow to the lungs can represent a valuable surgical option. Between November 1992 and December 1995, 21 patients with univentricular heart physiology were submitted to bidirectional cavopulmonary anastomosis with additional blood flow the additional flow consisted of an aortopulmonary shunt in 13 cases, pulmonary artery banding in seven cases, and pulmonary artery stenosis in one case. Mean age at operation was 35.5 months (range 4 months to 12 years) and mean body weight 10.9 (range 4-24.4) kg. Hospital mortality was zero. Morbidity (pleuropericardial effusions) was significant in one case. There were three late deaths (14%) caused by worsening atrioventricular valve regurgitation: two of these occurred in patients with right isomerism. Late haemodynamic evaluation documented a significant increase in cardiac output (P < 0.01) and oxygen saturation (P < 0.05) during pharmacological stress testing. Angiographic characterization of blood flow distribution to the lungs showed better results when the additional blood flow was represented by an anterograde source (pulmonary artery banding or native pulmonary artery stenosis). In conclusion, bidrectional cavopulmonary anastomosis with additional blood flow is a good alternative to classic or fenestrated Fontan technique in high-risk patients. Secondly, the diagnosis of isomerism could be a contraindication to this type of surgery, because the persistent volume overload could worsen atrioventricular valve regurgitation. Thirdly, the pharmacological stress testing shows a favourable behaviour of cardiac output and arterial oxygen saturation. Fourth, the type of additional blood flow seems to condition both pulsatility and distribution of pulmonary blood flow.

Goretex patch aortoplasty for coarctation in children: nuclear magnetic resonance assessment at 7 years.

From 1979 to 1990, 56 children ranging between 4 days and 16 years of age (mean 73 +/- 51 months) underwent Goretex patch aortoplasty for coarctation of the aorta. The mean weight at operation was 20.2 +/- 3.5 kg (range 3.3-42 kg). Forty-two patients had primary repair, and the remaining 14 had reoperation for recoarctation. The aorta was opened through a standard left thoracotomy, the posterior fibrous ridge was partially excised when it was prominent, and a large patch from a Goretex tube was sutured into place. The postoperative complications were as follows: paradoxical hypertension in 14 cases, massive haemorrhage due to aortic wall rupture in a diabetic child, and intestinal bleeding in 1 case. There were no early deaths and only 1 case of late death, which was not related to coarctation repair (mortality rate 1.8%). The average follow-up was 48 +/- 26 months. Continuous wave-Doppler examination at rest showed no arm-leg systolic gradient in 52 cases and a gradient of about 15 mmHg in 4 cases. Graded exercise testing showed only 1 case with an arm-leg gradient higher than 35 mmHg. Nuclear magnetic resonance (NMR) imaging, performed on 26 patients at a mean of 7 years from operation, showed excellent morphology and size of the aortoplasty. No cases of recoarctation or late aneurysm formation were found. We conclude that Goretex patch aortoplasty can be performed effectively and safely in children. Nuclear magnetic resonance provides high resolution imaging of the coarctation repair site.