Neonatal Arterial Switch Operation Research Articles

Sympathetic denervation and reinnervation after arterial switch operation for complete transposition.

Sympathetic cardiopulmonary nerves arise from the cervical sympathetic trunks and the stellate ganglia and subsequently course along the origin of the great arteries and the coronary arteries to innervate the ventricles. Therefore, the sympathetic nerves may be obligatorily interrupted by the arterial switch operation (ASO) for complete transposition of the great arteries. To demonstrate and characterize the possible sympathetic denervation, 51 patients after ASO, 4.8 years old (range, 1 month to 10.1 years), underwent [123I]metaiodobenzylguanidine (MIBG) imaging of the sympathetic nerve terminal. MIBG uptake to the heart was graded by quantitative analysis using the heart-to-mediastinum (H/M) ratio of MIBG uptake. A quantitative criterion for absent uptake of MIBG was set to 1.48 in the H/M ratio. Four patients < 1 month after ASO showed complete absence of MIBG uptake, which had been observed preoperatively. In contrast, 47 patients late after ASO (range, 15 months to 10.1 years) showed various degrees of uptake of MIBG. Patients operated on at < or =55 days of age showed positive MIBG uptake much more frequently than those operated on at later ages. Heart rate and rate-pressure product at peak exercise on a treadmill exercise test were significantly greater in patients with positive uptake than in those with absent uptake of MIBG. Cardiac sympathetic nerves were denervated early after and reinnervated late after ASO. Neonatal ASO may be favorable to facilitate sympathetic reinnervation, which may affect exercise tolerance late after surgery.

Fate Of The Neopulmonary Valve After The Arterial Switch Operation In Neonates

Objectives: The purpose of this study was to determine the incidence, risk factors, and outcomes of acquired stenosis of the neopulmonary valve after the neonatal arterial switch operation. Methods: Reviewed were the preoperative and follow-up echocardiograms from 136 of 288 patients undergoing the arterial switch operation for whom adequate studies were available. Pulmonary stenosis was defined as a thickened and doming pulmonary valve and a pressure gradient of 20 mm Hg or more. Transposition of the great arteries was present with intact ventricular septum in 91 patients, with a ventricular septal detect in 39, with an aortic coarctation in 5, and with double-outlet right ventricle in 1 patient. No patient had preoperative valvular abnormalities (i.e., a bicuspid valve). Results: During a median follow-up of 18 months (range <1 to 90 months), 32 patients (24%) had the development of supravalvular pulmonary stenosis, 15 (11%) with associated pulmonary valve stenosis (group I). Kaplan-Meier estimates of freedom from any intervention were 94% (95% confidence interval, 90% to 99%) at 1 year and 79% (95% confidence interval, 64% to 94%) at 5 years. The valve anulus before the arterial switch operation was significantly larger ( p < 0.03) in those in whom neopulmonary valve stenosis did not develop (group II) than it was in those in whom it did (group I). At follow-up, the pulmonary valve anulus had decreased significantly in diameter in group I ( p < 0.0005) and had remained larger in group II ( p = 0.06) compared with normal diameter. Group I patients had the development of significant pulmonary valve hypoplasia ( p < 0.03) whereas group II patients continued to have significantly larger valves compared with normal size ( p < 0.0001). Conclusions: Neopulmonary valve stenosis after the arterial switch operation is not uncommon and is associated with growth failure of the valve anulus often associated with supravalvular pulmonary stenosis. (J Thorac Cardiovasc Surg 1998;115:557-62)

Changing practice patterns for children with heart disease: a clinical pathway approach

Pediatric cardiac care is costly and requires extensive resources. We studied the effect of clinical pathways on practice patterns and patient care outcomes in infants and children hospitalized for cardiac surgery. In consecutive patients admitted for selected cardiac surgical procedures before (n = 69) and after (n = 173) implementation of clinical pathways, outcomes including hospital length of stay, days in the ICU, time to extubation, ordering of blood studies, costs, and readmissions were compared. Data were analyzed for each of five cardiac surgical procedures: repair of an atrial septal defect, repair of a ventricular septal defect, division of a patent ductus arteriosus, repair of tetralogy of Fallot, and neonatal arterial switch operation to correct transposition of the great arteries. A significant reduction in length of hospital stay, including days in the ICU (decreased 1 to 2 days per admission), was achieved after the clinical pathway was implemented. Reductions in average duration of mechanical ventilation ranged from 28% for repair of a ventricular septal defect to 63% for repair of tetralogy of Fallot. The number of blood studies ordered decreased 20% to 30%. A significant reduction in hospital costs for each procedure, ranging from 16% to 29%, was also achieved with no adverse effects on patients' outcomes. Use of clinical pathways with children hospitalized for cardiac surgery can shorten length of stay in the hospital, reduce use of resources, and improve cost-effectiveness with beneficial outcomes for patients.

Growth of pulmonary artery after arterial switch operation for simple transposition of the great arteries.

This retrospective study attempts to assess the size and growth pattern of the pulmonary artery about 1 year after neonatal arterial switch operation for simple transposition of the great arteries. Sixty-seven patients underwent cardiac catheterization, including catheterization of the right and left pulmonary arteries, and right ventricular angiography an average of 13.9 months after arterial switch operation. In 34 of these patients pre-operative right ventricular angiocardiograms were available. The diameter of the main pulmonary artery and that of its proximal right and left branches were measured. The values were compared to those of normal children matched for body surface area, taken from the literature and, for the branch values, related to the degree of branch stenosis and to the corresponding values, measured on pre-operative angiocardiograms. The cross-section of the main pulmonary artery after arterial switch operation with Lecompte manoeuvre becomes oval. The branches of the pulmonary artery are sometimes underdeveloped and this finding is related to branch stenosis. The ratio of the branch gradients is inversely proportional to the growth ratio of both branches while the pre- and postoperative Nakata indices are identical. The Lecompte manoeuvre induces a flattening of the main pulmonary artery with concomitant reduction of its cross-sectional area. There is also frequently trivial or rarely moderate branch pulmonary stenosis which is accompanied by growth retardation of the concerned branch.

Myocardial cell damage related to arterial switch operation in neonates and the role of pro-inflammatory, cytokines

Myocardial cell damage related to arterial switch operation in neonates and the role of pro-inflammatory, cytokines

Results of the Bruce Treadmill Test in Children After Arterial Switch Operation for Simple Transposition of the Great Arteries

Children who underwent arterial switch operation for simple transposition of the great arteries in the neonatal period are now reaching an age when exercise testing becomes feasible. This study was conducted to assess exercise tolerance and electrocardiographic response to exercise stress in 50 asymptomatic children, aged 4 to 9 years, using the Bruce walking treadmill protocol to voluntary exhaustion. Heart rate and blood pressure response to exercise stress, endurance time, and electrocardiographic changes were analyzed and compared with those of age-matched normal children. Forty-seven patients had normal exercise capacity and parameters. One patient, whose coronary angiogram showed occlusion of the left main coronary artery, developed electrocardiographic signs of myocardial ischemia during exercise. In 1 patient with a single right coronary artery ostium and in another, who underwent a neonatal internal mammary bypass graft for obstruction of the right coronary artery, the resting electrocardiogram showed ventricular premature complexes and exercise stress-induced salvos of ventricular tachycardia. We conclude that most of the children who underwent the neonatal arterial switch operation for simple transposition of the great arteries have a normal exercise capacity. Exercise testing appears to be useful in detecting ischemic damage or exercise-induced arrhythmias possibly secondary to reduced coronary flow reserve.

Cognitive and motor development in preschool and school-aged children after neonatal arterial switch operation

Objective: The developmental status of children beyond 3 years of age after the neonatal arterial switch operation has not yet been systematically evaluated and is the topic of the present work. Methods: Seventy-seven unselected children operated on as neonates with combined deep hypothermic circulatory arrest and low-flow cardiopulmonary bypass were examined at an age of 3.2 to 9.4 years (5.4 ± 1.6 years, mean ± standard deviation). Clinical neurologic status, standard scores of intelligence, acquired abilities and vocabulary, and standardized tests on gross motor and fine motor functions were carried out, and the results were related to preoperative, perioperative, and postoperative status and management. Results: Neurologic impairment was more frequent (9.1%) than in the normal population. Intelligence was not different in these patients compared with normal children ( p = 0.11), but motor function, vocabulary, and acquired abilities were poorer. Reduced intelligence was found in 9.1%, fine motor dysfunction in 22.1%, and gross motor dysfunction in 23.4% of the children. Intelligence was weakly but significantly inversely related to the duration of bypass (Spearman correlation coefficient –0.25, p = 0.03) and tended to be inversely related to the duration of circulatory arrest (–0.21, p = 0.07), but not to core cooling time on bypass or degree of hypothermia. Gross motor function, vocabulary, and acquired abilities were not significantly related to any of the perioperative parameters considered. No correlation was found between the test results and the variables perinatal asphyxia, perioperative and postoperative cardiocirculatory insufficiency, resuscitation events, and plexal or intraventricular cerebral hemorrhage. Conclusions: The neonatal arterial switch operation with combined circulatory arrest and low-flow bypass in our experience is associated with neurologic as well as fine and gross motor impairment but appears to be well tolerated concerning cognitive functions as based on formal intelligence testing. (J Thorac Cardiovasc Surg 1997;114:578-85)

Cardiological and general health status in preschool- and school-age children after neonatal arterial switch operation.

Cardiological and general health status 3-9 years after neonatal arterial switch operation for transposition of the great arteries should be evaluated by non-invasive methods. A total of 77 unselected children with intact ventricular septum (75.3%) or ventricular septal defect (24.7%) without or with aortic isthmic stenosis (5.2%) were prospectively examined 3.2-9.4 years (5.4 +/- 1.6) after neonatal switch. Clinical pediatric and cardiological examination, standard and 24 h Holter electrocardiogram, M-mode, 2D-, Doppler and colour Doppler echocardiography were performed. Outcome data were compared to published normals. Reoperation rate was 2.6%, 96.1% were without limitation of physical activity and 98.7% without medication. Compared to normals, growth was adequate, weight and head circumference were slightly reduced. After median sternotomy, 23.4% had abnormal thoracic configuration (16.9% asymmetry, 6.5% funnel chest). ECG and Holter: 93.5% were in sinus, 6.5% in ectopic atrial or junctional rhythm. Incidence of complete right bundle branch block was 15.8% in patients with ventricular septal defect and 5.2% in those without. Ischemic ST-T changes during exercise due to coronary artery occlusion and evidence of old myocardial infarction were found in 1 patient (1.3%) each. Occasional atrial ectopy was found in 27.4%, ventricular ectopy in 15.3%: occasional in 12.5% and frequent (> 30/h) in 2.8% presenting bigemini, couplets and short runs of ventricular tachycardia at rest and during exercise. Echocardiography: Left ventricular function was normal in all. Endsystolic diameter of neoaortic valve annulus was beyond 90% confidence interval for controls in 79.2%, neoaortic root diameter in 100%. Mild aortic insufficiency was seen in 10.4%. No correlation was found between aortic insufficiency and aortic dilatation. Neoaortic stenosis was not seen, mild residual coarctation after end-to-end-anastomosis was found in 2.6%, native coarctation corrected later on in 1.3%. Supravalvular pulmonary stenosis was seen in 29.9% (19.5% trivial, 7.8% mild, 2.6% moderate), mild subvalvular pulmonary stenosis in 1.3%, pulmonary insufficiency in 2.6%. The study confirms good midterm results after neonatal arterial switch operation for transposition with or without ventricular septal defect. Long-term observation is necessary to assess rhythm, coronary artery and myocardial function as well as development of neo-aorta and pulmonary artery system.

Angiographic study of aorta, coronary arteries, and left ventricular performance after neonatal arterial switch operation for simple transposition of the great arteries

This retrospective study attempts to assess the growth pattern of the aorta and the coronary arteries and the left ventricular function approximately 1 year after neonatal arterial switch operation for simple transposition of the great arteries. Seventy-one patients underwent cardiac catheterization and cineangiocardiography an average of 13.5 months after the operation. The diameters of aortic annulus, aorta at different sites, and coronary arteries were compared with normal ranges taken from the literature. Left ventricular systolic performance was also evaluated. Observations included the following: Neoaortic annulus and root were larger than normal, trivial or mild neoaortic regurgitation was frequently observed, and the development of aortic anastomosis was normal. One patient had unexpected coronary occlusion, one had a coronary artery fistula, and two had a hypoplastic left anterior descending coronary artery. Except in one child who underwent an internal mammary bypass graft immediately after anatomic correction, the global left ventricular performance was normal. Six patients had regional wall motion abnormalities. Our midterm results are encouraging, but potential late complications remain concerns that must continue to be evaluated in long-term follow-up studies.

Neonatal arterial switch operation: coronary artery patterns and coronary events.

To determine the incidence of coronary events following neonatal arterial switch and to identify potential risk factors for death and coronary events. The total experience (236 consecutive arterial switch operations) of one surgeon was studied. Associated procedures included ventricular septal defect closure in 37 patients (16%) and aortic arch repair in 14 patients (6%)). The influence of various patient, procedural, support technique and experience variables was analyzed. There were 19 deaths (8-70% confidence limits = 6-10%). Survival at 1 month, 1 year and 5 years was 93, 92 and 92%, respectively. Risk factors for death included small birth weight (P = 0.0015), hypoplasia of right ventricle (P < 0.0001), aortic arch obstruction (P < 0.0001) and coronary patterns with coronary arteries coursing between the great arteries (P = 0.0066). Coronary events occurred in 26 patients (11-70% confidence limits = 9-13%) and involved coronary deaths (11 patients), non fatal myocardial infarctions (8 patients) and coronary stenoses or occlusions (7 patients). Freedom from coronary events at 1 month, 1 year and 5 years was 94, 91 and 88%, respectively. Risk factors for coronary events included coronary patterns with retropulmonary course of the left main or left circumflex coronary artery (P = 0.0122), coronary patterns with coronary arteries coursing between the great arteries (P < 0.0001), all variations of intramural coronary arteries (P = 0.0010) and commissural origin of coronary ostia (P = 0.0171). (1) In most neonates, arterial switch operation carries a low operative risk and provides excellent mid-term results; (2) The operative risk remains increased in some subsets; and (3) Some coronary patterns increase the risk of coronary events. Further surgical experience may improve the results.

Postoperative Course and Hemodynamic Profile After the Arterial Switch Operation in Neonates and Infants

The neurological morbidity associated with prolonged periods of circulatory arrest has led some cardiac surgical teams to promote continuous low-flow cardiopulmonary bypass as an alternative strategy. The nonneurological postoperative effects of both techniques have been previously studied only in a limited fashion. We compared the hemodynamic profile (cardiac index and systemic and pulmonary vascular resistances), intraoperative and postoperative fluid balance, and perioperative course after deep hypothermia and support consisting predominantly of total circulatory arrest or low-flow cardiopulmonary bypass in a randomized, single-center trial. Eligibility criteria included a diagnosis of transposition of the great arteries and a planned arterial switch operation before the age of 3 months. Of the 171 patients, 129 (66 assigned to circulatory arrest and 63 to low-flow bypass) had an intact ventricular septum and 42 (21 assigned to circulatory arrest and 21 to low-flow bypass) had an associated ventricular septal defect. There were 3 (1.8%) hospital deaths. Patients assigned to low-flow bypass had significantly greater weight gain and positive fluid balance compared with patients assigned to circulatory arrest. Despite the increased weight gain in the infants assigned to low-flow bypass, the duration of mechanical ventilation, stay in the intensive care unit, and hospital stay were similar in both groups. Hemodynamic measurements were made in 122 patients. During the first postoperative night, the cardiac index decreased (32.1 +/- 15.4%, mean +/- SD), while pulmonary and systemic vascular resistance increased. The measured cardiac index was < 2.0 L.min-1.m-2 in 23.8% of the patients, with the lowest measurement typically occurring 9 to 12 hours after surgery. Perfusion strategy assignment was not associated with postoperative hemodynamics or other nonneurological postoperative events. After heart surgery in neonates and infants, both low-flow bypass and circulatory arrest perfusion strategies have comparable effects on the nonneurological postoperative course and hemodynamic profile.

The influence of coronary anatomy on the arterial switch operation in neonates

To determine whether coronary anatomy influences the outcome of the neonatal arterial switch operation, we examined the results in all newborn infants (n = 70) with D-transposition of the great arteries who had a corrective operation at our institution between March 1987 and April 1991. The origin and distribution of coronary arteries were identified preoperatively by echocardiography, aortic root angiography, or selective coronary arteriography and intraoperatively by direct inspection. However, the arterial switch operation was performed independent of the coronary anatomy in all but two candidates for the operation. Four early deaths occurred and five surviving patients had symptoms of impaired cardiac function. No late deaths have occurred in patients followed up for 2 to 50 months. Evidence of myocardial ischemia was present in three of the four deaths and in four of the five patients with cardiovascular symptoms. Patients with commissural or intramural coronary origins between the great arteries had significantly greater cardiovascular morbidity and mortality because of coronary ischemia than patients with the most common coronary pattern. Thus coronary anatomy may influence surgical management and the postoperative course of newborn infants with transposition.

Intermediate-term clinical and hemodynamic results of the neonatal arterial switch operation for complete transposition of the great arteries

We prospectively evaluated 49 consecutive hospital survivors of the arterial switch operation for complete transposition and intact ventricular septum by clinical examination, echocardiography, cardiac catheterization, 12-lead and 24-h Holter ECG. The mean length of follow-up was 40 ± 18 months. Forty-six children are clinically asymptomatic without medication, 2 died due to coronary related left ventricular dysfunction 3 and 12 months after surgery, and 1 required reoperation because of severe bilateral pulmonary branch stenoses. Except for this case, cardiac catheterization ( n = 23) revealed a mean gradient of only 17 ± 8 mmHg between the right ventricle and distal pulmonary arteries. Left ventricular end-diastolic volume was within normal limits except for 2 cases with volumes slightly below normal, the mean ejection fraction was 78 ± 5%, and end-diastolic and end-systolic ventricular shapes were normal. The mean cardiac index was 4.14 ± 0.69 l/min/m 2. Left ventricular end-systolic wall stress to velocity of fiber shortening relation was normal in all cases examined ( n = 15), indicating normal myocardial contractility. Significant neoaortic valve insufficiency was never observed despite considerably enlarged aortic roots. Twenty-four-hour Holter ECG records ( n = 46) provided no evidence of serious atrial arrhythmias, especially sinus node dysfunction. These encouraging intermediate-term results make the arterial switch operation the treatment of choice at present, for neonates with simple transposition.

Internal mammary artery bypass graft for impaired coronary perfusion after neonatal arterial switch operation

Myocardial ischaemia caused by perfusion impairment of translocated coronary arteries is the major cause of perioperative mortality after neonatal arterial switch operation for transposition of the great arteries. We report the successful use of the right internal mammary artery as a bypass graft to a dominant right coronary artery to treat insufficient perfusion of this artery in a newborn. Eight months later, coronary angiography showed a full blood supply of the right coronary artery across the internal mammary anastomosis. After a follow-up period of more than 30 months, somatic development, electrocardiogram and echocardiographically determined contractility of both ventricles are practically normal indicating regular function of the bypass graft.

An anterior longitudinal aortotomy with a distal aortic transection for the arterial switch operation

An additional longitudinal aortotomy on the anterior aspect of the old ascending aorta after distal aortic transection is very effective for removal of the coronary buttons, prevention of deformation of the neopulmonary arterial ring, and reconstruction of the neopulmonary arterial trunk after the Lecompte maneuver, especially for the neonatal arterial switch operation.

Transposition of the Great Arteries: The Arterial Switch Operation

Primary arterial switch operation in neonates for repair of transposition of the great arteries with an intact ventricular septum or with a ventricular septal defect has become the operation of choice in our institution. By now, the surgical risk has been decreased to approximately 2 per cent. Early in our experience, postoperative supravalvar pulmonary stenosis was the only late hemodynamic complication of significance. Postoperative left ventricular function, including echocardiographic indices of left ventricular function, including echocardiographic indices of left ventricular systolic and diastolic function, have been within normal range in all patients. Almost all patients are in sinus rhythm as late as 6 years of the operation. It is our contention that primary arterial switch operation in infants with transposition of the great arteries results in improved left ventricular performance; the potential hazard of late coronary insufficiency and of aortic valve dysfunction requires continued monitoring of these patients.

The hemodynamic results of the arterial switch operation in neonates with transposition of the great arteries and intact ventricular septum

The hemodynamic results of the arterial switch operation in neonates with transposition of the great arteries and intact ventricular septum

Transposition of the Great Arteries and Intact Ventricular Septum: Anatomical Repair in the Neonate

Fourteen neonates 18 hours to 32 days old with transposition of the great arteries (TGA) and virtually intact ventricular septum (IVS) underwent arterial switch operations under deep hypothermic circulatory arrest. Preoperative left ventricular to right ventricular peak systolic pressure ratios ranged from 0.7 to 1.0 (mean, 0.92), and the echocardiogram showed a centrally positioned ventricular septum in 10 patients and a rightward displaced ventricular septum in 4. One patient died twelve hours after operation. Postoperative complications included bleeding from the left coronary artery-pulmonary artery anastomosis (1 patient), stenosis of the pulmonary artery-aorta anastomosis requiring reoperation (2 patients), transient ST segment and T wave abnormalities consistent with ischemia (3), and development of pathological Q waves suggestive of clinically silent infarction (2). The capacity of the left ventricle in a neonate to effectively take over the systemic circulation was clearly demonstrated. A longer follow-up period is needed to assess late ventricular function, coronary ostial growth, growth of the aorta-pulmonary artery anastomosis, late aortic valve (anatomical pulmonary valve) function before definitive recommendations about the superiority of the arterial switch operation in neonates with TGA plus IVS can be formulated.