Atrial switch (Senning procedure) in the era of the arterial switch operation: current indications and results

OBJECTIVE: Since 1990, the policy at Oregon Health Sciences University is to perform an arterial switch for all patients with transposition of the great arteries. In the last four years we have performed the Senning operation in two patients. Our impression is that the long-term results with Senning procedure at our center are quite good. This prompted a review of our experience with this procedure. METHODS: A retrospective review of all patients' charts was undertaken to document preoperative and operative clinical variables. During follow-up, emphasis was placed on reviewing all cardiology clinic charts, transthoracic echocardiograms and ambulatory holter monitor logs. Transthoracic echocardiograms and 24 hour Holter monitoring were performed yearly on all patients during follow-up. RESULTS: Since September, 1982, 54 patients underwent the Senning operation for transposition of the great arteries. All patients were palliated at birth with the Rashkind atrial septostomy. The interatrial septum was reconstructed with a dacron patch, and the systemic and pulmonary venous baffles were constructed with autogenous atrial tissue. All but 2 patients underwent profound hypothermia and total circulatory arrest during their operative repair. Of 54 patients, early mortality occurred in 5 patients (9%). Follow-up is complete for the 49 operative survivors. The length of follow-up ranges from 6.0 months to 12.1 years (mean 6.4 +/- 0.5 years). There are no late deaths. Forty-five patients (94%) are in NYHA Class I. All late survivors are in sinus rhythm with brief episodes of junctional rhythm (32 patients). CONCLUSIONS: Our series demonstrates that the Senning operation can be safely performed in early infancy. Further, it provides excellent symptomatic and clinical outcomes during late follow-up. Thus, in the era of the arterial switch procedure, close and complete late follow-up results with the Senning procedure, as in this series, should be considered the benchmark in the continued evaluation of the arterial switch operation.     

The double switch procedure for anatomical repair of congenitally corrected transposition of the great arteries in infants and children

AIMS: To assess outcomes of anatomical repair (double switch procedure) in infants and children with congenitally corrected transposition of the great arteries. METHODS AND RESULTS: Between September 1993 and August 1996, 17 patients with congenitally corrected transposition underwent surgery at UCSF. Anatomical repair was performed in 11 of these patients, at ages ranging from 4.8 months to 7.8 years (median 3.2 years). The remaining six patients did not undergo anatomical repair due to unfavourable anatomy (n = 2), prior conduit repair (n = 2), biventricular dysfunction (n = 1), and isolated complete atrioventricular block (n = 1). The 11 patients who underwent anatomical repair make up the study group for the present report. All 11 patients had a malalignment ventricular septal defect, while pulmonary outflow tract obstruction was present in nine patients and significant tricuspid valve pathology or dysfunction was present in five. Anatomical repair was achieved with a Senning (n = 7) or a Mustard (n = 4) procedure combined with an arterial switch operation plus ventricular septal defect closure (n = 4), or a Rastelli procedure with left ventricle to aortic baffle and right ventricle to pulmonary artery conduit (n = 7). There was one early death and no patients developed surgical complete atrioventricular block. At a median follow-up of 22 months, there were no late deaths. Two patients required a total of three late reoperations, and all patients were asymptomatic on no cardiac medication. Follow-up echocardiography revealed normal biventricular function in all patients. CONCLUSIONS: Anatomical repair of corrected transposition can be achieved with low rates of early mortality and surgical heart block, and favourable mid-term results. Long-term follow-up will be necessary to determine if the double switch approach improves the natural history of corrected transposition when compared to less aggressive surgical approaches that leave the right ventricle in the systemic circulation.     

Results of the Bruce treadmill test in children after arterial switch operation for simple transposition of the great arteries

In a double-blind, placebo-controlled clinical trial (power of 80% to detect a 30% reduction in morphine consumption, P < 0.05) we have determined that intraoperative intravenous administration of tenoxicam 40 mg during laparoscopic cholecystectomy, when compared with placebo, was associated with a significant reduction in consumption of morphine at 6 hours and 12 hours (P < 0.05) but not at 24 hours, when assessed by patient-controlled analgesia. Furthermore there was a significantly greater requirement for "rescue" analgesia with intramuscular morphine in the placebo group during the period of the study. There was no difference between the groups in pain scores, either at rest or on movement, nor in the incidence of nausea and vomiting. No patient in either group suffered a respiratory rate less than 8/min or oversedation at any time, and there were no other adverse effects.     

Subpulmonary obstruction in congenitally corrected transposition of the great arteries due to ventricular membranous septal aneurysms

The clinical, hemodynamic, and angiographic observations, as well as the surgical approach used for repair in three patients with congenitally corrected transposition of the great arteries and ventricular membranous septal aneurysms, are presented. In two of the three patients the membranous septal aneurysm caused subpulmonary obstruction, with 94 and 125 mm Hg systolic gradients. In each patient the aneurysm was demonstrated by angiocardiography, which also showed differences in size and shape with cardiac systole and diastole. Review of the previously described reports indicates that patients with congenitally corrected transposition often display various forms of pulmonary outflow obstruction and when a ventricular membranous septal aneurysm exists, a significant subpulmonary obstruction is present in most patients. The unique anatomic relationship between the pulmonary artery and a ventricular membranous septal aneurysm in patients with transposition of the great arteries with and without atrioventricular discordance explains why subpulmonary obstruction sometimes develops.     

Results of rapid two-stage arterial switch operation in patients with transposition of the great arteries: one-year postoperation

The rapid two-stage arterial switch operation is an alternative therapy for patients with simple transposition of the great arteries who present beyond the neonatal period and have low left ventricular pressure. It provides normal ventricular function compared to the atrial switch operation. Between July 1994 and February 1997, there were 13 such infants who had rapid two-stage arterial switch operation performed at Siriraj Hospital. There was 1 late death (11 months after the operation). All 12 survivors (mean age 22.4 +/- 5.7 months) were clinically evaluated and had echocardiography performed at 14.8 +/- 4.9 months after the operation. All were asymptomatic. Echocardiogram revealed a residual small atrial septal defect (1 case), small ventricular septal defect (1 case), mild supravalvar neopulmonary stenosis (2 cases), bicuspid neoaortic valve without stenosis (2 cases), dilated neoaortic sinus of Valsalva (6 cases, 50%) and mild neoaortic insufficiency (11 cases, 91.7%). The left ventricular function was hyperdynamic after pulmonary artery banding and significantly decreased to normal level at the time of study (shortening fraction of 43.8 +/- 10.7 vs 29.2 +/- 3.8%, respectively, p = 0.0005). The wall thickness was significantly increased after pulmonary artery banding and decreased overtime (0.48 +/- 0.08 vs 0.32 +/- 0.05 cm, respectively, p < 0.0005). The left ventricular dimension was significantly increased both after pulmonary artery banding and at the time of study (2.06 +/- 0.42 vs 3.32 +/- 0.30 cm, respectively, p < 0.0005). The left ventricular mass was significantly increased after pulmonary artery banding and at the time of study (21.79 +/- 7.79 vs 33.08 +/- 7.40 g/m2, respectively, p = 0.0005). The mortality and morbidity of rapid two-stage arterial switch operation are low. However, long-term follow-up should be monitored.     

Ventricular tachycardia: a life-threatening arrhythmia in a patient with congenitally corrected transposition of the great arteries

Ventricular tachycardia (VT) is an uncommon finding in patients with congenitally corrected transposition of the great arteries (CCTGA). Cardiac death in patients with CCTGA has been attributed to complete heart block, systemic ventricular dysfunction, or severe AV valve regurgitation with heart failure. We describe the case of a patient who presented with palpitations and near-syncope that was associated with clinical episodes of VT. Programmed ventricular stimulation revealed easily inducible sustained VT that immediately degenerated to ventricular fibrillation and subsequently required therapy with an implantable cardioverter defibrillator.     

Mortality in potential arterial switch candidates with transposition of the great arteries

OBJECTIVE: Prostatic abscesses are uncommon in clinical practice because early antibiotic therapy has reduced complications of prostatitis. Prostatic abscess mainly affects diabetic and immunosuppressed patients. The organisms most frequently involved are Escherichia coli and Staphylococcus, whereas gonococcus is rarely encountered. The results in eight men with prostatic abscess, five of whom were treated with sonographically guided percutaneous drainage, are reported. The diagnosis, clinically suspected in only three patients, was confirmed by transrectal sonography. All patients experienced complete abscess resolution. CONCLUSION: Transrectal sonography is the most reliable imaging method to diagnose prostatic abscess. Percutaneous transperineal or transrectal drainage is the first choice for therapy because of the lower risk of complication compared with surgery.     

Regression of tricuspid regurgitation after two-stage arterial switch operation for failing systemic ventricle after atrial inversion operation

The cases of five patients with previous Senning (n = 4) or Mustard (n = 1) operations and failing systemic ventricles in whom banding of the pulmonary artery was performed as an interim step toward an arterial switch procedure are reported. The rise in the ratio of left to right mean systolic ventricular pressure, from 0.35 before operation to 0.90 during operation and 0.80 on the first postoperative day, caused a shift of the ventricular septum from a leftward to a midline or nearly midline position. This shift was associated with a reduction of tricuspid regurgitation. At a median interval of 5.1 months after pulmonary artery banding, the mean left ventricular posterior wall thickness had increased to 8.2 mm, versus 5 mm before operation, and the mean left ventricular myocardial mass index had increased to 90 gm/m2, versus 55.6 gm/m2 before operation. After the arterial switch operation, which was performed in four patients, the tricuspid regurgitation decreased to a trivial amount (n = 1) or disappeared completely (n = 3).     

Simulation analysis of interatrial transposition of venous return (Mustard's operation)

Transposition of the great arteries is functionally corrected by Mustard's operation, an operation in which the atrial septum is removed and the resulting common atrial chamber repartitioned by a baffle to transpose venous return to the heart. To better understand the new physiology, a physically-based mathematical model of the infant circulation following Mustard's operation was developed and studied with the aid of computer simulation. The model reproduces certain clinical observations, including the tendency for mean pressure in both atria to be equal early postoperatively and for the pressure waveform to exhibit a steep y-descent in the systemic venous atrium. Simulation studies suggest that the mechanism for the former is transbaffle pressure coupling resulting from dynamic motion of the baffle; the mechanism for the latter is limitation of the extent of such baffle excursions. Dynamic volume of the two atria is found in the model to change according to the relative performance of the two ventricles, and stiffening the baffle leads to pressure waveforms characteristic of a small, noncompliant atrium. Mechanisms for venous "obstruction" and decompression were also studied. The baffle and its movements, however, have little effect upon cardiac output in the model, leaving unexplained the clinical observation of low output early postoperatively.     

Exercise studies in patients with transposition of the great arteries after atrial repair operations (Mustard/Senning): a review

Exercise evaluation studies of patients after atrial repair surgery for transposition of the great arteries, as in tetralogy of Fallot, represent only a small fraction of the 3970 Medline references (1966 to mid-1997) concerning this congenital heart lesion. We have abstracted data from 27 studies from 20 institutions reporting on measurements during exercise on work capacity, heart rate response, respiratory gas exchange, or radionuclide/radiographic systemic ventricular ejection fraction measurements in addition to resting pulmonary function measurements. These studies provide almost uniform general conclusions that even after 20 or more years of follow-up (1) most patients "report" that they are asymptomatic in performing usual levels of physical activities; (2) significant abnormalities are present, often in more than half of the patients studied, in one or more of the exercise measurements when compared to control subjects; and (3) the diminished exercise performance is related to a diminished cardiac output, results from diminished stroke volume but is also related to a blunted heart rate response.     

Switching of the great vessels (arterial switch surgery) in transpositio vasorum

Since April 1992 the arterial switch operation (ASO) has been the treatment of neonates with transposition of the great arteries (TGA) at Rigshospitalet, Copenhagen. Thirteen mature neonates with TGA underwent ASO. Ten patients had simple TGA, two had TGA associated with a ventricular septal defect (VSD), and one had TGA with VSD and in addition moderate right ventricular hypoplasia. All patients survived the operation and are still alive. Perioperative bleeding was a problem in three cases. Eleven patients had an uncomplicated postoperative course. One patient had peri- and postoperative left ventricular failure and was reoperated after three months for a residual VSD. One child developed renal failure and needed peritoneal dialysis. The patients have been followed for 5.5 (range 0-12) months, they are all in good condition and thriving well. The presented early results after ASO justify continued recommendation of ASO as the operation of choice for TGA in neonates at Rigshospitalet.     

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

OBJECTIVE: 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. 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. RESULTS: 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%. CONCLUSION: 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.     

Haemodynamics after Mustard's operation for transposition of the great arteries

Cardiac catheterization data from 54 investigations after Mustard's procedure were examined to study the influence of the operation on pressure events in the atria, great veins, and pulmonary circulation. Systemic venous atrial pressure tracings were characterized by a rapid, sharp 'y' descent. Pressure gradients between the venae cavae and systemic venous atrium were invariable, whether or not vena caval pathway obstruction was present, the 'y' trough and 'a' wave gradients being greater than the mean gradient. Pulmonary venous atrial pressure tracings were not different from normal except when tricuspid regurgitation was present. It is suggested that the baffle effectively reduces the size and compliance of the systemic venous atrium, but influences the pulmonary venous atrium to a lesser degree. The systolic pressure gradient from the left ventricle to pulmonary artery was decreased postoperatively, suggesting that it may be flow-related; the greatest changes were seen in the group with preoperative ventricular septal defect. The ratio of pulmonary: systemic vascular resistance did not change significantly after operation, and it is suggested that both the pre- and postoperative values were higher than normal. Examination of the left ventricular or pulmonary arterial mean pressure postoperatively should raise the suspicion of a complication, e.g. pulmonary venous obstruction or tricuspid regurgitation.     

Late re-interventions following arterial switch operations in transposition of the great arteries. Incidence and surgical treatment of postoperative pulmonary stenosis

Seventy-six patients were studied after arterial switch operation (ASO) between May 1977 and February 1992. Pulmonary artery reconstruction was initially performed by: conduit interposition in 5 patients, direct main pulmonary artery anastomosis and button patches in 60 patients, and pantaloon-like patch repair in 11 patients. Pulmonary stenosis developed in 17 patients (22%), requiring a total of 26 late re-interventions. Re-intervention was required in four out of five patients operated with pulmonary artery conduits, 11 out of 60 with a button patch repair and 2 out of 11 following pantaloon-type repair. In this series pulmonary artery stenosis (PS) involving the pulmonary valve occurred in 9/17 patients. Involvement of the pulmonary valve was related to the technique of pulmonary artery reconstruction. In these patients surgery is necessary. Balloon angioplasty can be a valuable tool when the stenosis is more distal. The incidence of PS was not influenced by the type of reconstruction or the use of Lecompte's maneuver.     

Successful term pregnancy after Mustard operation for transposition of the great arteries

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.     

A congenitally "poor" pulmonary artery is a major reason for exclusion from Fontan operation

We reviewed the clinical records of 185 patients who were possible candidates for Fontan operation. We did this to clarify whether all patients with suitable anomalies ultimately underwent a Fontan operation. Of the 152 patients with decreased pulmonary blood flow, 38 (26%) did not fulfill the criteria for Fontan operation, and 17 of the 33 patients (52%) with increased pulmonary blood flow (P < 0.01) were excluded as candidates. Of 48 non-candidate survivors, 19 had high pulmonary artery (PA) pressure or resistance and small PA (which we term "poor PA"), 17 had pulmonary hypertension, 6 had a markedly distorted PA, and 6 had severe ventricular dysfunction. A significant proportion of possible candidates with a suitable anomaly ultimately did not undergo a Fontan operation, because of "poor PA", a congenital condition that precluded Fontan operation.     

Cardiac output response to dynamic exercise after atrial switch repair for transposition of the great arteries

Results from this study showed that patients who underwent successful operation for transposition of the great arteries had no appropriate increase in stroke volume in response to exercise of a nature similar to common recreational activities. The impairment, most likely due to disturbances in both venous return and ventricular systolic function, is compensated for by an increase in peripheral oxygen extraction; however, this increase may not be adequate with maturation or during prolonged exercise when cardiovascular constraints are more important.