Surgical options for complex transposition of the great arteries.

Between September 1976 and November 1987, 53 patients underwent surgical treatment by the same surgeon for "complex transposition of the great arteries" with ventricular septal defect or severe left ventricular outflow tract obstruction, or both. Six patients with transposition and left ventricular outflow tract obstruction underwent atrial rerouting and direct relief of the left ventricular outflow tract obstruction. Twenty-two patients presented with transposition plus ventricular septal defect; 15 of these patients underwent atrial rerouting and ventricular septal defect closure and 7 underwent an arterial switch procedure. Twenty-five patients presented with transposition plus ventricular septal defect and left ventricular outflow tract obstruction, 23 of whom underwent a Rastelli procedure. There were one early death (mortality rate 1.9%; 90% confidence limits 0-7%) and three late deaths (mortality rate 5.8%) during a mean follow-up period of 42 months (range 2 to 124). These results show that 1) atrial rerouting is an appropriate surgical procedure for transposition of the great arteries with left ventricular outflow tract obstruction; 2) the arterial switch procedure provides excellent early correction of transposition with ventricular septal defect and is currently the preferred procedure for this lesion; and 3) the Rastelli procedure can be performed with a low early mortality rate and excellent long-term results for transposition with ventricular septal defect and left ventricular outflow tract obstruction.

von Willebrand factor ristocetin cofactor (VWF:RCo) assay: implementation on an automated coagulometer (ACL).

BACKGROUND: VWF:RCo assay is the standard and widely used laboratory test for von Willebrand disease (VWD) diagnosis. It is hampered by high intra- and inter-assay imprecision and is time consuming. Automation may improve the assay performance and allow its routine application. OBJECTIVE: Automation of VWF:RCo on the ACL 7000 coagulometer (Instrumentation Laboratory, Milan, Italy) and its evaluation in VWD diagnosis. METHODS AND MATERIALS: Method performance determination: precision, detection limit (DL), interferences, dose-response curve. Method comparison: analysis of 105 plasma samples from normal subjects (50), VWD type 1 (24), VWD type 2 (24) and VWD type 3 (7) with ACL VWF:RCo and comparison with the reference aggregometric (AGM) method. RESULTS: ACL VWF:RCo: CVs around 10% vs. 19% of AGM method; DL: 0.08 U mL(-1); potential interferences from bilirubin, triglycerides and hemoglobin, avoided by suitable plasma dilution; high correlation with AGM VWF:RCo (Deming regression Y =-0.0277 + 1.0519X) either in normal or VWD plasmas. In VWD types 1 and 2, the VWF:RCo/VWF:Ag ratios are >0.6 or <0.6, respectively, when calculated with both AGM and ACL VWF:RCo values. CONCLUSIONS: The automated VWF:RCo on the ACL 7000 coagulometer shows precision improvement and high correlation with the reference AGM method. The test allows the diagnosis of both quantitative (VWD types 1 and 3) and qualitative (VWD type 2) forms of the disease. These results and the assay feasibility make it a suitable and reliable test for the routine diagnosis of VWD.

Oxidative injury in reoxygenated and reperfused hearts.

In this study, we separated the effects of low oxygen supply and low coronary flow in isolated perfused rat hearts to focus on the genesis of free radicals-induced reperfusion injury. Hearts were exposed to either hypoxemia/reoxygenation or ischemia/reperfusion in various sequences, with hypoxemia and ischemia matched for duration (20 min), temperature (37 degrees C), and oxygen supply (10% of baseline). Hypoxemia/reoxygenation (n = 7) resulted in lower (developed pressure) x (heart rate) (p < 0.001) and higher end-diastolic pressure (p < 0.001) than ischemia/reperfusion (n = 9). The presence of 40 IU/ml superoxide dismutase and 104 IU/ml catalase nearly blunted the rise of the end-diastolic pressure (p = 0.02 vs. baseline), but could only partially prevent the depression of myocardial contractility (p < 0.001 vs. baseline, n = 7). Similar patterns were observed when hearts were made ischemic after hypoxemia, eliminating the intermediate reoxygenation step. We conclude that the major determinant of the reperfusion injury is associated with low oxygen supply rather than low coronary flow. Part of the injury is mediated by oxygen-derived free radicals, but a substantial portion of it is associated with energetic processes.

Spontaneous closure of inlet ventricular septal defect in an infant with Down's syndrome and aortic coarctation.

Ventricular septal defect (VSD) is considered one of the most common congenital heart diseases in patients with Down's syndrome. It is well known that some VSDs show a tendency to diminish in size and to close. To our knowledge, in patients with Down's syndrome spontaneous closure of a perimembranous inlet VSD has not been described before. The prevalence of some cardiac malformations and the rarity of others have been reported in patients with Down's syndrome. Left ventricular outflow tract obstruction rarely occurs in patients with Down's syndrome. A case of Down's syndrome with coarctation of the aorta, patent ductus arteriosus, and perimembranous inlet VSD that spontaneously closed by formation of aneurysm of the membranous septum is reported.

Atrioventricular septal defects with severe left ventricular hypoplasia. Staged palliation.

The natural and surgical history of patients with atrioventricular septal defect, severe left ventricular hypoplasia and right ventricular dominance is poor. We report a successful case of staged surgical palliation based on regulation of the pulmonary blood flow and creation of an unobstructed systemic outlet.

Inferior vena cava-pulmonary artery extracardiac conduit. A new form of right heart bypass.

From November 1988 to May 1989, four patients underwent total right heart bypass by means of bidirectional cavopulmonary anastomosis and interposition of an extracardiac conduit from the inferior vena cava to the pulmonary artery. All of them had an uneventful postoperative course, and there have been no early or late deaths. We propose this technique as an alternative surgical option in candidates for a Fontan procedure with (1) hypoplasia or atresia of the left atrioventricular valve, (2) common atrioventricular valve, (3) anomalies of systemic and pulmonary venous return, or (4) auricular juxtaposition.

The hypoplastic mitral valve. When should a left atrial-left ventricular extracardiac valved conduit be used?

Limited experimental and clinical experience with extracardiac bypass of the mitral valve has been reported. We describe the case history of a 3-year-old child in whom a left atrial-left ventricular valved conduit was successfully used to bypass a severely hypoplastic parachute mitral valve. The potential applications of this unconventional surgical option are reviewed.

Bronchial compression by dilated pulmonary artery. Surgical treatment.

Bronchial compression by a dilated left pulmonary artery complicated the postoperative course in two infants: one after a Mustard operation for transposition of the great arteries, restrictive ventricular septal defect, and moderate pulmonary stenosis, the second after correction of tetralogy of Fallot with absent pulmonary valve. In both cases the bronchial compression was successfully treated by division of the left pulmonary artery and its prolongation by interposition of a conduit.

Balloon occlusion of the carotid artery for the angiographic visualization of Blalock-Taussig shunts and pulmonary arteries.

We describe the use of a balloon catheter to occlude the right or left carotid artery as a way of directing contrast material to the pulmonary arteries. This procedure was carried out in the postoperative study of 14 children who had undergone a Blalock-Taussig shunt. The method was reliable, and the angiograms provided excellent visualization of the pulmonary arteries using only small volumes of contrast material.

Cardiac rhabdomyoma: surgical treatment in the neonate.

Primary cardiac tumors are rare. Of the benign lesions, rhabdomyoma predominates in infants and children. The natural history of patients with cardiac rhabdomyoma is poor. About 50% die in the first month of life and 80% by 1 year of age. We report on the two youngest infants ever operated upon successfully for removal of symptomatic ventricular cardiac rhabdomyoma. The operations were performed through a left ventriculotomy in one and through a right ventriculotomy in the other during the first day of life.

Airway obstructions associated with congenital heart disease in infancy.

Significant airway obstruction may complicate the natural and surgical history of infants with congenital heart diseases. Airway obstruction occurred in 12 infants who had operations for congenital heart disease. In all cases tracheography demonstrated the cause of airway obstruction. Significant mortality (5/12, 41.7%) and morbidity in this group of infants were the result of airway obstruction. To reduce the complications caused by airway obstruction in infants with congenital heart disease, we recommend (1) preoperative identification of patients with potential airway obstruction, (2) preoperative tracheography in high-risk infants, (3) appropriate choice of the surgical procedure, especially when insertion of a prosthetic conduit is required, (4) early recognition of the problem during the postoperative period, (5) prompt diagnosis by postoperative tracheography, with or without angiography, and (6) therapy directed at the cause of airway obstruction.

Surgical bypass of the systemic atrioventricular valve in children by means of a valved conduit.

The surgical approach to relief of mitral stenosis in children is still a controversial problem. We describe our experience with four severely symptomatic children in whom a valved conduit from the left atrium to the left ventricle was successfully used to bypass a hypoplastic systemic atrioventricular valve. A left atrial-left ventricular extracardiac conduit was implanted in these patients with a hypoplastic mitral anulus and an adequate left ventricular chamber. There were no early or late deaths. Postoperative cardiac catheterization performed in all patients 1 month after the operation showed reduced size of the left atrium, a reduction of the left atrial-left ventricular gradient from a mean of 14 mm Hg to a mean of 5 mm Hg, and an increase of the left atrial outlet from a mean diameter of 10.7 mm to 28.7 mm (including the diameter of the native mitral valve plus the internal diameter of the valved conduit). The application of this unconventional operation in children with congenital or acquired stenosis of the systemic atrioventricular valve should be considered when the mitral valve obstruction cannot be relieved by conventional valve repair or replacement. Furthermore, the left atrial-left ventricular conduit does not preclude future alternative surgical options.

Discrete subaortic stenosis. Surgery in children based on two-dimensional and Doppler echocardiography.

Twenty pediatric patients underwent surgical resection of a "discrete" subaortic membrane. The diagnosis and the surgical indication were based on two-dimensional and Doppler echocardiography without cardiac catheterization and angiography. In all patients the echocardiographic diagnosis was confirmed at surgery in terms of presence, dimension and location of the membrane and in ten patients in terms of pressure gradients. Two-dimensional and Doppler echocardiography has proved to be a very reliable tool for the diagnosis and surgical indication in pediatric patients with a DSAS. Our criteria for the selection of surgical patients are the following: (1) isolated form of discrete subaortic stenosis with a short base of attachment to the ventricular septum; (2) pressure gradients higher than 25 mm Hg; (3) presence of significant aortic insufficiency. All of this information can be consistently obtained with two-dimensional and Doppler echocardiography.

"Acquired" subvalvular aortic stenosis after repair of a ventricular septal defect.

Of 353 children who underwent surgical repair of a congenital heart defect, including closure of a ventricular septal defect (VSD), 12 patients (four with tetralogy of Fallot, five with a VSD, and three with a double-outlet right ventricle) developed subaortic stenosis, which was diagnosed one to six years after the surgical procedure. Five patients required surgical treatment of the subaortic stenosis, and one required percutaneous balloon angioplasty. Postsurgical subaortic stenosis appears to be an uncommon progressive acquired disease.

Prevention of reperfusion injury in the neonatal heart with leukocyte-depleted blood.

Activated leukocytes release oxygen free radicals and cause microvascular occlusion. This experiment tests the hypothesis that reperfusion with leukocyte-depleted blood reduces injury after extended ischemic preservation. An in vitro model consisting of an isolated, working neonatal piglet heart and an adolescent support pig was used. Hearts were arrested with a cold crystalloid cardioplegic solution, excised, and stored in 4 degrees C saline for 12 hours. Two groups were compared. In group 1 piglets (n = 8), reperfused with whole blood, the maximum stroke work index was 0.91 +/- 0.29 x 10(3) erg/gm (mean +/- standard error of the mean). Group 2 piglets (n = 6), reperfused with blood depleted of leukocytes by a polyester filter, had a maximum stroke work index of 11.6 +/- 1.0 x 10(3) erg/gm. This difference was highly significant (p less than 0.0001). Group 1 exhibited severe injury with myofibrillar necrosis, mitochondrial disruption, nuclear chromatin clumping, and moderate interstitial edema. Group 2 had normal ultrastructure on electron microscopic examination. We conclude that reperfusion with leukocyte-depleted blood prevents reperfusion injury and results in excellent myocardial function after long-term heart preservation.

Long-term neonatal heart preservation.

UNLABELLED: Donor availability is a major limiting factor in neonatal heart transplantation. Prolonging donor heart preservation would facilitate distant heart procurement. Forty-two neonatal (1 to 5 days) piglet hearts in seven groups were arrested with cold cardioplegic solutions, stored for 12 hours at 4 degrees C in storage solutions, and reperfused with blood from an adult support pig. The cardioplegic solutions used were a crystalloid solution with potassium chloride 30 mEq/L and bicarbonate (Stanford), the Stanford cardioplegic solution with the addition of calcium (1.2 mmol/L), or an intracellular solution (Sacks) with added glucose. Storage solutions were normal saline, Sacks II, or Sacks II with glucose 20 gm/L. Reperfusion was done with normal blood or modified blood for 20 minutes with superoxide dismutase, catalase, aspartate, glutamate, citrate-phosphate-dextrose, potassium, tromethamine, and 50% dextrose followed by normal blood. Evaluation of stroke work index after 60 minutes of recovery (as percent of control) was performed using the isolated, blood perfused, working heart preparation in all groups: Group I (Stanford cardioplegia, saline storage, normal blood reperfusion) had a recovery of 11%; group II (Stanford + calcium, saline, normal blood) 8%; group III (Stanford + calcium, saline, modified blood, superoxide dismutase 35,000 U/L, catalase 35,000 U/L) 37%; group IV (Stanford + calcium, Sacks II, modified blood, superoxide dismutase 35,000 U/L, catalase 35,000 U/L), 47%; group V (Stanford + calcium, Sacks + glucose, modified blood, superoxide dismutase 35,000 U/L, catalase 105,000 U/L) 89%; group VI (Stanford + calcium, Sacks + glucose, modified blood, superoxide dismutase 150,000 U/L, catalase 150,000 U/L) 107%; group VII (Sacks + glucose, Sacks + glucose, modified blood, superoxide dismutase 35,000 U/L, catalase 105,000 U/L) 115%. CONCLUSIONS: The neonatal heart stored hypothermically for 12 hours tolerates normal blood reperfusion poorly. Modified blood reperfusion markedly improves the recovery. Complete functional recovery was achieved by the intracellular Sacks plus glucose storage solution and modified blood reperfusion with oxygen-derived free radical scavengers (high catalase). Extended preservation of the neonatal heart is feasible.

Myocardial protection in the neonatal heart. A comparison of topical hypothermia and crystalloid and blood cardioplegic solutions.

UNLABELLED: Myocardial protection achieved during 2 hours of ischemic arrest was evaluated in 45 isolated, blood perfused, neonatal (1 to 5 days) piglet hearts. Comparisons were made among five methods of myocardial protection: Group I, topical cooling; Group II, hyperosmolar (450 mOsm) low-calcium (0.5 mmol/L) crystalloid cardioplegia; Group III, St. Thomas' Hospital cardioplegia; Group IV, cold blood cardioplegia with potassium (21 mmol/L), citrate-phosphate-dextrose (calcium level 0.6 mmol/L), and tromethamine; and Group V, cold blood cardioplegia with potassium alone (16 mmol/L) (calcium level 1.2 mmol/L). Hemodynamic recovery (percent of the preischemic stroke work) after 30 and 60 minutes of reperfusion was 82.9% and 86.7% in Group I, 35.7% (p less than 0.0001) and 43.7% (p less than 0.0001) in Group II, 76.1% and 77.7% in Group III, 67.4% (p less than 0.05) and 60.6% (p less than 0.05) in Group IV, and 110.7% and 100.6% in Group V. CONCLUSIONS: Topical cooling is an effective method of myocardial protection in the neonate. Cold blood cardioplegia with potassium alone and a normal calcium level provides optimal functional recovery. The improved protection obtained with both crystalloid and blood cardioplegia with normal calcium levels suggests an increased sensitivity of the neonatal heart to the calcium level of the cardioplegic solution.

Regulation of bioenergetics in O2-limited isolated rat hearts.

Assessing the role of O2 supply in the regulation of cardiac function in O2-limited hearts is crucial to understanding myocardial ischemic preconditioning and adaptation to hypoxia. We exposed isolated Langendorff-perfused rat hearts to either ischemia (low coronary flow) or hypoxemia (low PO2 in the perfusing medium) with matched O2 supply (10% of baseline). Myocardial contractile work and ATP turnover were greater in hypoxemic than in ischemic hearts (P < 0.05; n = 12). Thus, the energy demand was higher during hypoxemia than during ischemia, suggesting that ischemic hearts are more downregulated than hypoxemic hearts. Venous PO2 was 12 +/- 2 and 120 +/- 15 Torr (P < 0.0001) for ischemic and hypoxemic hearts, respectively, but O2 uptake was the same. Lactate release was higher during hypoxemia than during ischemia (9.7 +/- 0.9 vs. 1.4 +/- 0.2 mumol/min, respectively; P < 0.0001). Electrical stimulation (300 min-1; to increase energy demand) increased performance in ischemic (P < 0.005) but not in hypoxemic hearts without changes in venous PO2 or O2 uptake. However, venous lactate concentration and lactate release increased in ischemic (P < 0.002) but not in hypoxemic hearts, suggesting that anaerobic glycolysis provides the energy necessary to meet the increased energy demand in ischemic hearts only. We conclude that high intracellular lactate or H+ concentration during ischemia plays a major role as a downregulating factor. Downregulation disappears in hypoxemic hearts secondary to enhanced washout of lactate or H+.

Modified Blalock-Taussig shunt with compensatory properties.

Determination of the proper length of the tubular prosthesis is a major issue when performing a systemic-pulmonary artery shunt. The procedure is simplified by using a prosthesis with accordionlike properties. This was demonstrated in 7 consecutive infants with complex congenital heart defects, in whom systemic-pulmonary artery shunts were placed without early or late complications.