Results of the arterial switch operation for transposition of the great arteries with ventricular septal defect. Surgical considerations and midterm follow-up data

Application of a modified clinical classification for pulmonary arterial hypertension associated with congenital heart disease in children: emphasis on atrial septal defects and transposition of the great arteries. An analysis from the TOPP registry

Aims

A proportion of patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) do not fit in the current classification. We aimed to analyse the applicability of an adapted clinical classification of PAH-CHD to pediatric patients using the TOPP-1 registry (Tracking Outcomes and Practice in Pediatric Pulmonary Hypertension) and focus on atrial septal defects (ASD) and transposition of the great arteries (TGA).

Methods and results

Hemodynamic and clinical data of all patients with PAH-CHD in the TOPP cohort were reviewed. Patients were classified according to predefined ABCDE categories (A: Eisenmenger syndrome, B: left-to-right shunt, C: coincidental defects, including all ASDs, D: corrected CHD, E: TGA), or as complex CHD (group 5), by 2 independent investigators. In case of disagreement, a third reviewer could either settle a final decision, or the patient was deemed not classifiable. Survival curves were calculated for each group and compared to idiopathic PAH patients of the registry. A total of 223 out of 531 patients in the registry had PAH-CHD, and 193 were categorized to the following groups: A 39(20%), B 27(14%), C 62(32%) including 43 ASDs, D 58(30%), E 7(4%), whereas 6 patients were categorized as group 5, and 10 patients were unable to be classified. No survival difference could be demonstrated between the groups.

Conclusions

This modified classification seems to be more applicable to pediatric PAH-CHD patients than the previous classification, but some patients with PAH-CHD who never had a shunt remain unclassifiable. The role of ASD in pediatric PH should be reconsidered.

Outcomes after Arterial Switch Operation for Simple Transposition

Without intervention, babies born with transposed great arteries (TGA) are doomed to a rapid death. Jatene and coworkers deserve the credit for performing the first successful arterial switch operation (ASO) in a patient with TGA and ventricular septal defect (VSD) in 1975. Since then ASO has become the procedure of choice in most medical centers. This review article summarizes the historical aspects of arterial switch operation and assesses this procedure's outcomes.

Severe Pulmonary Vascular Obstructive Disease After Neonatal Arterial Switch Operation for Simple Transposition of the Great Arteries

Neonatal arterial switch operation for simple dextro-transposition of the great arteries (d-TGA) has almost eliminated the occurrence of pulmonary vascular obstructive disease compared to patients who underwent Mustard or Senning procedure at an older age. We report a case of a neonate with d-TGA and intact ventricular septum who underwent arterial switch operation and yet developed severe pulmonary vascular obstructive disease within two months.

Development of Standardized Clinical Assessment and Management Plans (SCAMPs) in Plastic and Reconstructive Surgery

Background:

With rising cost of healthcare, there is an urgent need for developing effective and economical streamlined care. In clinical situations with limited data or conflicting evidence-based data, there is significant institutional and individual practice variation. Quality improvement with the use of Standardized Clinical Assessment and Management Plans (SCAMPs) might be beneficial in such scenarios. The SCAMPs method has never before been reported to be utilized in plastic surgery.

Methods:

The topic of immediate breast reconstruction was identified as a possible SCAMPs project. The initial stages of SCAMPs development, including planning and implementation, were entered. The SCAMP Champion, along with the SCAMPs support team, developed targeted data statements. The SCAMP was then written and a decision-tree algorithm was built. Buy-in was obtained from the Division of Plastic Surgery and a SCAMPs data form was generated to collect data.

Results:

Decisions pertaining to “immediate implant-based breast reconstruction” were approved as an acceptable topic for SCAMPs development. Nine targeted data statements were made based on the clinical decision points within the SCAMP. The SCAMP algorithm, and the SDF, required multiple revisions. Ultimately, the SCAMP was effectively implemented with multiple iterations in data collection.

Conclusions:

Full execution of the SCAMP may allow better-defined selection criteria for this complex patient population. Deviations from the SCAMP may allow for improvement of the SCAMP and facilitate consensus within the Division. Iterative and adaptive quality improvement utilizing SCAMPs creates an opportunity to reduce cost by improving knowledge about best practice.

Ventricular sympathetic innervation in patients with transposition of the great arteries after arterial switch operation and Rastelli procedure: impact of arterial dissection and coronary reimplantation

BACKGROUND

Coronary flow reserve (CFR) is reduced in patients with transposition of the great arteries (TGA) after the arterial switch operation (ASO). Dissection of the great arteries and coronary reimplantation may result in sympathetic denervation, with a negative effect on myocardial perfusion.

METHODS AND RESULTS

18 patients with TGA participated in the study; 9 had ASO (20.8±5.8 years). Controls were 9 patients after Rastelli procedure (22.1±6.8 years). Sympathetic innervation was measured by positron emission tomography using(11)C epinephrine (EPI). Left ventricular EPI-retention ranged from 6.1% to 15.9%/min. Patients undergoing more than 1 operation had significantly reduced EPI-retention (P<0.001). EPI-retention and time interval after surgery correlated significantly (r=0.81, P<0.001) and was higher in patients undergoing surgery at an earlier age (P<0.001). No significant difference could be found between patients after ASO or Rastelli repair. Aortic cross-clamp time inversely correlated with EPI-retention (r=-0.72; P<0.001).

CONCLUSIONS

The ASO procedure had a negative effect on sympathetic innervation of the myocardium, but because of reinnervation myocardial perfusion is not essentially altered by this mechanism. Heart surgery and prolonged aortic cross-clamp time have a negative effect on the norepinephrine content of cardiac sympathetic nerve terminals. Parameters such as ventricular performance and cardiopulmonary exercise capacity were unaffected by the degree of EPI-retention.

Transposition of great arteries: new insights into the pathogenesis

Transposition of great arteries (TGA) is one of the most common and severe congenital heart diseases (CHD). It is also one of the most mysterious CHD because it has no precedent in phylogenetic and ontogenetic development, it does not represent an alternative physiological model of blood circulation and its etiology and morphogenesis are still largely unknown. However, recent epidemiologic, experimental, and genetic data suggest new insights into the pathogenesis. TGA is very rarely associated with the most frequent genetic syndromes, such as Turner, Noonan, Williams or Marfan syndromes, and in Down syndrome, it is virtually absent. The only genetic syndrome with a strong relation with TGA is Heterotaxy. In lateralization defects TGA is frequently associated with asplenia syndrome. Moreover, TGA is rather frequent in cases of isolated dextrocardia with situs solitus, showing link with defect of visceral situs. Nowadays, the most reliable method to induce TGA consists in treating pregnant mice with retinoic acid or with retinoic acid inhibitors. Following such treatment not only cases of TGA with d-ventricular loop have been registered, but also some cases of congenitally corrected transposition of great arteries (CCTGA). In another experiment, the embryos of mice treated with retinoic acid in day 6.5 presented Heterotaxy, suggesting a relationship among these morphologically different CHD. In humans, some families, beside TGA cases, present first-degree relatives with CCTGA. This data suggest that monogenic inheritance with a variable phenotypic expression could explain the familial aggregation of TGA and CCTGA. In some of these families we previously found multiple mutations in laterality genes including Nodal and ZIC3, confirming a pathogenetic relation between TGA and Heterotaxy. These overall data suggest to include TGA in the pathogenetic group of laterality defects instead of conotruncal abnormalities due to ectomesenchymal tissue migration.

Late manifestation of coarctation of the aorta after arterial switch operation for D-transposition of the great arteries with intact ventricular septum

We describe an infant with D-transposition of the great arteries with an intact ventricular septum who developed coarctation of the aorta 13 days after arterial switch operation. A mildly hypoplastic aortic isthmus was present on echocardiogram at the time of the arterial switch operation, but there was no echocardiographic or clinical evidence of coarctation of the aorta.

Late Atrio-ventricular Block After Arterial Switch for D-transposition of the Great Vessels With Intact Interventricular Septum

Arterial switch operation for transposition of the great arteries without ventricular septal defect usually does not lead to atrio-ventricular conduction disturbances. We discuss the case of a young boy presenting with first and second degree supra hisian atrio-ventricular block late after switch operation.

Echocardiography as a hemodynamic monitor in critically ill children

Echocardiography is a widely used modality to assess myocardial structure and function in pediatric intensive care settings. While the use of echocardiography for diagnostic purposes remains important, its use as a hemodynamic monitoring tool has not been well established. The benefits of echocardiography are in its widespread availability, relative ease of use, and importance in diagnosing structural disease and simple changes in myocardial function. However, echocardiography in pediatric critical care is limited in its use because it requires the acquisition of quality images and the accurate interpretation of the study. To date, the literature on echocardiography in pediatric critical care is limited. The purpose of this review is to examine the scientific evidence for the usefulness of echocardiography as a hemodynamic monitoring tool in pediatric critical care.

Resource utilization after introduction of a standardized clinical assessment and management plan

INTRODUCTION

A Standardized Clinical Assessment and Management Plan (SCAMP) is a novel quality improvement initiative that standardizes the assessment and management of all patients who carry a predefined diagnosis. Based on periodic review of systemically collected data the SCAMP is designed to be modified to improve its own algorithm. One of the objectives of a SCAMP is to identify and reduce resource utilization and patient care costs.

METHODS

We retrospectively reviewed resource utilization in the first 93 arterial switch operation (ASO) SCAMP patients and 186 age-matched control ASO patients. We compared diagnostic and laboratory testing obtained at the initial SCAMP clinic visit and control patient visits. To evaluate the effect of the SCAMP over time, the number of clinic visits per patient year and echocardiograms per patient year in historical control ASO patients were compared to the projected rates for ASO SCAMP participants.

RESULTS

Cardiac magnetic resonance imaging (MRI), stress echocardiogram, and lipid profile utilization were higher in the initial SCAMP clinic visit group than in age-matched control patients. Total echocardiogram and lung scan usage were similar. Chest X-ray and exercise stress testing were obtained less in SCAMP patients. ASO SCAMP patients are projected to have 0.5 clinic visits and 0.5 echocardiograms per year. Historical control patients had more clinic visits (1.2 vs. 0.5 visits/patient year, P<.01) and a higher echocardiogram rate (0.92 vs. 0.5 echocardiograms/patient year, P<.01)

CONCLUSION

Implementation of a SCAMP may initially lead to increased resource utilization, but over time resource utilization is projected to decrease.

Late-onset pulmonary arterial hypertension after a successful atrial or arterial switch procedure for transposition of the great arteries

Common complications after surgery for transposition of the great arteries (TGA) include systemic ventricular dysfunction and arrhythmia after atrial baffle repair (AB) and outflow tract stenosis or regurgitation after the arterial switch (AS). Severe pulmonary hypertension (PHT) is a rarely reported problem after AB and AS. In this study we sought to evaluate the frequency of late onset severe PHT following surgical repair for TGA. We report 3 cases, 2 after AB and 1 after AS, describe the frequency of this complication and treatment response, by comparing the response to pulmonary vasodilators in this group of patients to that of idiopathic or connective tissue disease (CTD) related PHT. We currently follow 85 patients >or=17 years of age with repaired TGA; 77 after AB and 8 after AS. 3.5% of our adult congenital heart disease patients with TGA have developed late severe PHT. None of these patients demonstrated clinical improvement with Bosentan at 6 months, however 2 of 3 were stabilised with the addition of Sildenafil to initial therapy. The third patient died 4 months after the diagnosis of severe PHT, whilst waiting for heart-lung transplantation, despite Bosentan, Sildenafil and inotropic support. By contrast, of 37 patients with idiopathic or CTD related PHT commenced on Bosentan as initial therapy, 32 (86.5%) demonstrated a clinical response at 6 months; the other patients had Sildenafil as added therapy after 6 months. Our data suggest that patients with TGA and late onset PHT are less likely to achieve a clinical response on pulmonary vasodilator monotherapy (P = 0.006). Whilst more investigation is needed, our experience suggests an aggressive clinical course, often requiring combination PHT treatment.

Ventricular function in patients with transposition of the great arteries operated with arterial switch

The study aim was to investigate ventricular function at long-term follow-up in patients operated with arterial switch for transposition of the great arteries (TGAs). Although midterm results for anatomic correction of TGA are promising, there are reported minor alterations in left ventricular (LV) function possibly indicating myocardial dysfunction. Twenty-two patients with TGAs 12.4 +/- 2.3 years old operated with arterial switch were studied by magnetic resonance imaging and echocardiography. Twenty-two age-matched healthy subjects served as controls. Myocardial deformation was described by longitudinal and circumferential shortening (measured as strain and strain rate) and ventricular torsion, measured by speckle-tracking echocardiography. Although standard measurements of global systolic LV function were normal in patients with TGAs, longitudinal shortening was decreased compared with controls. Longitudinal strain was decreased in all ventricular regions except the posterior wall and most pronounced in the apical segments. LV circumferential shortening was similar in the 2 groups. Also, in the right ventricular free wall patients displayed decreased longitudinal shortening in the mid and apical segment. Moreover, LV torsion was decreased in the TGA group. Although rotation was relatively homogenous at the apical and basal levels in controls, there was greater dispersion in rotation in the patient group, with basal rotation being greatest in the inferior wall and apical rotation being greatest in the anterior wall. In conclusion, there was slightly decreased longitudinal shortening in the 2 ventricles and decreased LV torsion in patients with TGAs, although standard measurements of global ventricular function were normal.

Anatomical correction of complex forms of transposition of the great arteries in neonates

OBJECTIVE

The arterial switch operation has become the procedure of choice for the simple transposition of the great arteries (TGA) while in the complex forms of the defect the staged approach is frequently implemented. The aim of this study is to compare groups of patients with simple transposition and children with the complex form of the defect and identify factors affecting early and late outcome.

DESIGN

From 1997 to 2003, 135 consecutive neonates with TGA underwent arterial switch operation and simultaneous reparation of all associated defects. Univariate and multivariate analysis of perioperative variables and follow-up data was performed. Patients were divided into two groups. Group I (n=84, 62.2%) included neonates with simple transposition (TGA/IVS), Group II (n=51, 37.8%) included children with complex transposition (TGA/VSD).

RESULTS

Overall early mortality was 8.1% and there was one late death (0.7%). One-month, 1-year and 5-year actuarial survival rates were 91.8, 91.1 and 91.1%, respectively. There were no differences in the early and late survival rate between groups. Reintervention rate for right ventricular outflow tract obstruction (RVOTO) was 13.3% (balloon plasty or reoperation). The freedom from reintervention at 1, 3 and 5 years was 98.4, 87.9 and 85.4%, respectively. There were no differences in the need for reintervention between groups. The significant differences between groups concerned: age at operation (p<0.001), associated anomalies (p=0.002) including aortic arch anomalies (p=0.002) and coronary artery anomalies (p=0.02), application of delayed chest closure (p=0.015), and occurrence of sepsis (p=0.032). Risk factors for early death were: left ventricule dysfunction related to age at operation (p=0.016) and resternotomy in intensive care unit (p<0.001). There were no differences between groups concerning these risk factors as far as circulatory arrest time, aorta clamping time, and early and late morbidity.

CONCLUSIONS

The arterial switch operation can be the treatment of choice for various forms of TGA with low early and late mortality and morbidity rates. The main cause of early death is still left ventricular dysfunction. Such well-known predictors of poor outcome as presence of ventricular septal defect, coronary artery anomalies and aortic arch anomalies did not affect early and late findings. The presented approach of early simultaneous anatomical correction of TGA and all associated anomalies ensures good condition of children with low necessity for reintervention.

Aortic valve regurgitation after arterial switch operation for transposition of the great arteries: incidence, risk factors, and outcome

OBJECTIVES

The aims of this study were to assess the prevalence and incidence of aortic valve regurgitation (AR) after arterial switch operation (ASO), its outcome, and the risk factors.

BACKGROUND

After an ASO, the long-term fate of the aortic valve is a concern as follow-up lengthens.

METHODS

Operative and follow-up data on 1,156 hospital survivors after ASOs between 1982 and December 2000 were reviewed.

RESULTS

At last follow-up (mean duration 76.2 +/- 60.5 months), 172 patients (14.9%) had an AR. Complex transposition of the great arteries, prior pulmonary banding done in 75 patients (21 with intact ventricular septum), aortic arch anomalies, AR at discharge, older age at ASO, and aortic/pulmonary size discrepancy were associated with AR. On multivariate analysis, the presence of a ventricular septal defect (VSD) or AR at discharge multiplied the risk by 2 and 4, respectively. Freedom from AR was 77.9% and 69.5% at 10 and 15 years, respectively; hazard function for AR declined rapidly and slowly increased thereafter. Reoperation from AR was done in 16 patients with one death, valvuloplasty being unsuccessful. Freedom from reoperation for AR was 97.7% and 96.8% at 10 and 15 years, respectively; hazard function slowly increased from 2 to 16 years. Higher late mortality was not associated with AR.

CONCLUSIONS

After ASO, AR was observed and was related to VSD with attending high pressure and flow and AR at discharge. Progression of AR was slow, but incidence increased with follow-up. Reoperation for AR was rare. Late aortic valve function warrants long-term monitoring.

Late Results After PTCA for Coronary Stenosis After the Arterial Switch Procedure for Transposition of the Great Arteries

BACKGROUND

The arterial switch operation has become the surgical approach of choice for d-transposition of the great arteries, but there is an increased awareness of adverse sequelae in some survivors. Long-term patency and normal function of the translocated coronary arteries must be achieved. It is reported that dependent of the prior coronary status, 3% to 11% of all survivors have proximal coronary stenosis or complete occlusion develop after arterial switch operations. However, treatment of these stenoses is still a matter of debate. Late results after percutaneous transluminal coronary angioplasty (PTCA) for coronary stenosis after the arterial switch operation for d-transposition of the great arteries are reported.

METHODS

Seven children after arterial switch operation for d-transposition of the great arteries who had subsequently undergone PTCA for coronary stenosis were angiographically re-evaluated 3 to 15 months after the initial PTCA and again after 3 to 5 years.

RESULTS

All children survived the initial PTCA procedure. There were no late deaths. The degree of stenosis before PTCA ranged from 74% to 97%; immediately after PTCA from 5% to 10%; at 3 to 15 months after PTCA from zero to 6%; and at 3 to 5 years after PTCA from zero to 3%. Three to 5 years after PTCA all children showed normal development of the treated coronary artery.

CONCLUSIONS

Primary PTCA of stenotic proximal coronary arteries after the arterial switch procedure for d-transposition of the great arteries seems to be an effective treatment with excellent long-term results.

Assessment of left ventricular function long term after arterial switch operation for transposition of the great arteries by dobutamine stress echocardiography

OBJECTIVES

To use dobutamine stress echocardiography to determine left ventricular (LV) function and wall motion of children long term after arterial switch operation (ASO) for transposition of the great arteries.

DESIGN AND PATIENTS

31 patients (24 boys) with ASO performed at a mean (SD) of 15.5 (4.3) days of life were studied at an age of 9.4 (2.0) years. All had normal coronary angiographic findings. LV echocardiographic indexes, including fractional shortening, ejection fraction, rate corrected velocity of circumferential fibre shortening (VCFc), and wall stress, as well as LV wall motion abnormalities were determined at rest and under dobutamine stress. The results were compared with those of 20 healthy age matched control participants.

SETTING

Tertiary paediatric cardiac centre.

RESULTS

Fractional shortening, ejection fraction, and VCFc were significantly lower in patients than in controls at rest (all with p < 0.001). Stress-velocity index detected impaired LV contractility in 19 (61%) patients at rest. An older age at operation (p = 0.01), longer bypass (p = 0.01) and circulatory arrest times (p = 0.045), and an unusual coronary artery pattern (p = 0.059) were associated with impaired resting LV contractility. Dobutamine stress echocardiography unmasked wall motion abnormalities in 23 (74%) patients. Exercise myocardial perfusion scan, performed in 22 patients, showed reversible myocardial perfusion defects in 17. These defects corresponded to segments of hypokinesia as detected by dobutamine stress echocardiography.

CONCLUSION

A significant proportion of children, albeit asymptomatic, had impaired baseline LV contractility and reversible myocardial perfusion defects and mild wall motion abnormalities on stress after ASO.

Successful late reintervention after the arterial switch procedure

BACKGROUND

The arterial switch operation is the therapy of choice for transposition of the great arteries.

METHODS

A retrospective analysis of all children undergoing the arterial switch operation between November 1985 and October 2000 was conducted, highlighting the frequency and nature of late invasive reintervention.

RESULTS

One hundred forty-four children were operated on. Operative survival was 89% (128 of 144). Late reintervention was required in 23% (29 of 128) of survivors. Neopulmonary stenosis (PS) was the most common complication requiring treatment, occurring in 16% (21 of 128) of patients. Eleven of 21 patients with PS required reoperation, whereas 10 were managed with percutaneous techniques. Other indications for reintervention included aortic arch obstruction (3 patients), ventricular septal defect (with PS in 2 patients), bronchial stenosis (2 patients), coronary stenosis (2 patients), aortic stenosis (with PS in 1 patient), and residual atrial septal defect (1 patient). There has been no mortality or major morbidity in those children who have undergone reintervention.

CONCLUSIONS

Invasive reintervention after the arterial switch operation is occasionally required. The most common indication is PS. Reintervention is well tolerated by those children who require it. Continued follow-up for late complications is required in this patient population.

Intermediate outcome after Mustard and Senning procedures: A study by the Congenital Heart Surgeons Society

Although atrial switch is rarely performed today except as part of a "double switch" operation, there continues to be interest in the long-term outcome of the procedure because of the many Mustard and Senning survivors who are in follow-up. In contrast to most other reported series on atrial switch, this study by the Congenital Heart Surgeons Society (CHSS) is a prospective multiinstitutional study of patients encountered in a relatively short time frame during the late 1980s. Between 1985 to 1989, 20 centers with surgeons belonging to the CHSS prospectively registered patients <15 days of age presenting with simple or complex transposition of the great arteries (TGA). The patients were assigned to protocol groups based on intent to treat (arterial switch, Mustard, or Senning). Data were abstracted in the Data and Analysis Center, which in most cases, conducted the annual follow-up. Among the 281 patients who had an atrial switch, there were 108 Mustard and 173 Senning procedures. For the combined atrial switch population, the survival at 1 month, 5 years and 10 years was 90%, 85%, and 84%, respectively. Results for the Mustard were better than for the Senning with survival at 1 month, 5 years, and 10 years being 96% versus 86%, 95% versus 80%, 93% versus 78%; (P <.001) for Mustard versus Senning. While the major mortality risk occurred in the first postoperative month for both groups, thereafter, the late rate of death from 1 to 10 years after operation was 0.78%/year Senning versus 0.23%/year Mustard (P <.05). TGA/ventricular septal defect (VSD), lower weight, younger age, cardiac positional anomalies, and procedures on the left ventricle (LV) outflow all correlated significantly with poor outcome. There were 19 reoperations including 2 for right ventricle (RV) failure, 12 for pathway obstruction, and 5 for baffle leak with a 36% overall mortality. Freedom from any pathway obstruction at 10 years was 95%. A permanent pacemaker was required in 21 patients with the significant risk factors including TGA/VSD and a Senning, and previous atrial septectomy. Freedom from a pacemaker insertion at 10 years was 91%. For both Mustard and Senning, 60% of patients were in New York Heart Association (NYHA) functional Class I with the remaining in Class II. This study of atrial switch outcomes by the CHSS suggests that the subgroup undergoing a Mustard procedure had better early and late survival than those undergoing a Senning operation. The overall incidence of baffle pathway obstruction was low though reoperation for this complication carried high risk. Serious arrhythmia requiring medication and the need for a permanent pacemaker were both relatively uncommon. The incidence of severe right heart failure was very low, although only 60% of patients are unrestricted in their activity. Copyright 2000 by W.B. Saunders Company

Arterial switch operation: factors impacting survival in the current era

BACKGROUND

The arterial switch procedure has become the preferred procedure for the transposition of the great arteries (TGA) and Taussig-Bing anomaly. This analysis is intended to identify potential factors affecting survival in the current era.

METHODS

From 1986 to 1999, 201 consecutive patients underwent an arterial switch operation for TGA or Taussig-Bing anomaly. Multivariate analysis of perioperative variables was performed for operative morbidity/ mortality. Patients were separated into two groups. Phase 1 (n = 29) included patients before mid-1989 who underwent an open coronary reimplantation technique. Phase 2 (n = 172) included the patients undergoing a technique of reimplanting coronary buttons after neoaortic reconstruction.

RESULTS

The patient population included TGA with intact ventricular septum (58.7%, 118 of 201), with ventricular septal defect (31.3%, 61 of 201), and Taussig-Bing anomaly (10.0%, 22 of 201). Overall, early mortality was 9.5% (19 of 201) and there were five late deaths (2.7%). One-month, 1-year, and 5-year actuarial survival rates were 90.4%, 87.9%, and 87.9%, respectively. Reoperation rate for late pulmonary stenosis was 2.7% (5 of 182). The freedom from reoperation at 3 and 5 years was 97.5% and 93.3%, respectively. In the analysis by time period, the operative mortality declined from 27.6% (8 of 29) to 6.4% (11 of 172) (p = 0.002). Risk factors for operative death were coronary artery patterns (usual vs retropulmonary left coronary artery, p = 0.009) in phase 1 and preoperative instability in phase 2 (p = 0.002).

CONCLUSIONS

The arterial switch operation for TGA and Taussig-Bing anomaly has early low and late mortality and reoperation rates. Technical modifications in coronary reimplantation have minimized coronary artery pattern-related risks.

Anatomical risk factors for mortality and cardiac morbidity after arterial switch operation

BACKGROUND

The arterial switch operation (ASO) is the treatment of choice for transposition of the great arteries.

METHODS

Anatomical risk factors on mortality and morbidity were analyzed retrospectively in 312 patients who underwent ASO between 1982 and 1997.

RESULTS

Survival was 95%, 92%, and 92% after 30 days, 5, and 10 years, respectively. Operative survival improved after 1990 to 97% (p < 0.001). Risk factors for operative mortality were complex anatomy (p = 0.018), coronary anomalies (p = 0.008), and prolonged bypass time (p < 0.001). Determinants of late mortality were coronary distribution (p = 0.03), position of the great arteries (p = 0.0095), bypass time (p = 0.047), and aortic coarctation (p = 0.046). After a follow-up of 3.6 +/- 2.7 years (0.1 to 14.9 years), 98% had good left ventricle function, 94% were in sinus rhythm, 2.4% had moderate to severe pulmonary stenosis, 0.3% had significant aortic regurgitation, and 1% had coronary stenosis. Freedom from reoperation was 100%, 96%, and 94% after 1, 5, and 10 years, respectively. No preoperative anatomic parameter correlated with long-term morbidity.

CONCLUSIONS

ASO can be performed with low operative mortality (< 5%) and long-term morbidity. Malformations associated with complex transposition of the great arteries influence early and late mortality.

Arterial switch procedure for D-transposition of the great arteries: quantitative midterm evaluation of hemodynamic changes with cine MR imaging and phase-shift velocity mapping-initial experience

PURPOSE

To evaluate cine magnetic resonance (MR) imaging and phase-shift velocity mapping for assessment of the hemodynamic relevance of stenotic segments or specific hemodynamic changes in the great vessels after an arterial switch procedure for correction of D-transposition of the great arteries.

MATERIALS AND METHODS

Twenty consecutive patients (age range, 2-17 years) with an acoustic window that was insufficient for Doppler transthoracic echocardiography were included in the study. Flow and diameter measurements of the pulmonary arterial trunk and its primary branches were performed with phase-shift velocity mapping and cine MR imaging.

RESULTS

There were good correlations between pressure gradients in the pulmonary arteries estimated with MR imaging and those measured with Doppler echocardiography (r = 0.83, n = 15) and cardiac catheterization (r = 0.90, n = 13). Cine MR imaging revealed that the diameters of the right and left pulmonary arteries decreased with the expansion of the aorta during systole, which increased the peak velocity. This temporary stenosis was more severe in the right than in the left pulmonary artery and was accompanied by a significantly (P <.05) lower volume flow in the right artery.

CONCLUSION

The anatomic situation after arterial switch repair tended to produce temporary stenoses in the primary pulmonary arterial branches, with significant changes in hemodynamics. These changes may affect the long-term outcome and go undetected with other imaging modalities.

Long-term survival and functional follow-up in patients after the arterial switch operation

BACKGROUND

For many years, the arterial switch operation (ASO) has been the therapy of choice for patients with transposition of the great arteries (TGA). Although excellent short- and mid-term results were reported, long-term results are rare.

METHODS

Between May 1983 and September 1997, ASO was performed on 285 patients with simple TGA (n = 171), TGA with ventricular septal defect (VSD) (n = 85), and Taussig-Bing (TB) anomaly (n = 29). This retrospective study describes long-term morbidity and mortality over a 15-year period.

RESULTS

Hospital mortality was 3.5% for simple TGA, 9.4% for TGA with VSD, and 13.8% for TB anomaly. Late death occured in 2 patients, 1 with simple TGA and 1 with TGA and VSD. The cumulative survival for all patients at 5 and 10 years is 93%, and at 15 years is 86%. Reoperations were required in 31 patients and were most common for stenosis of the right ventricular outflow tract (RVOT). However, no correlation was found between technical variations on pulmonary artery reconstruction and this type of complication. Forty-six patients underwent follow-up angiography, which revealed five cases with coronary occlusion or stenosis. Follow-up is complete in 96% of the patients from 1 to 15.2 years. Sinus rhythm is present in 97%; 88% of the patients show no limitations on exertion.

CONCLUSIONS

The ASO can be performed with low early mortality, almost absent late mortality, and infrequent need for reoperation. The favorable long-term results demonstrate that the ASO can be considered as the optimal approach for patients with TGA and special forms of double-outlet right ventricle.

Surgical management of transposition of great arteries associated with multiple ventricular septal defects

OBJECTIVE

The presence of associated multiple ventricular septal defects (VSDs) increases the risk of the anatomic repair for transposition of the great arteries (TGA). The aim of this study was to define the optimal management of this complex anomaly.

METHODS

Between January 1988 and December 1998, 45 patients underwent anatomic repair of TGA associated with multiple VSDs. The median age was 50 days and the median weight 4 kg. Eighteen (40%) had undergone previous palliation including 17 pulmonary artery banding procedure (PAB), seven associated with coarctation repair and one isolated coarctation repair. The perimembraneous septum was involved in 24 patients, the trabecular in 43, the inlet in seven and the infundibular in two. Closure of the VSDs included Dacron or pericardial patchs and matress sutures. The initial approach was through right atriotomy which was sufficient in 15 patients. VSDs were closed through right ventriculotomy in 13 patients, through pulmonary artery in six, through the aorta in one and in the remaining (n = 10) combined approaches were used. Only one patient required left apical ventriculotomy.

RESULTS

There were five hospital deaths (11%; 70% CL: 6-18%) including the one early reoperation for residual VSD closure. Five patients had successful early reoperation for secondary PAB for residual VSD. Three late deaths occurred (7%; 70% CL: 3-13%). At the last visit, 95% of survivors were asymptomatic and without any cardiac medication.

CONCLUSION

Mid-term survival with good quality of life can be achieved following either one or two-stage repair of this complex anomaly. In the presence of VSD closure failure a secondary PAB may be the procedure of choice.

Myocardial blood flow and coronary flow reserve late after anatomical correction of transposition of the great arteries

OBJECTIVES

Myocardial blood flow (MBF) in children late after arterial switch operation (ASO) was investigated quantitatively by positron emission tomography (PET).

BACKGROUND

In children with transposition of the great arteries (TGA), ASO is widely accepted as the management of choice. The long-term patency of coronary arteries after surgical transfer to the neo-aorta, however, remains a concern.

METHODS

Twenty-two normally developed, symptom-free children were investigated by PET with nitrogen-13 ammonia at rest and during adenosine vasodilation 10+/-1 years after ASO. A subgroup of 15 children (9+/-1 years; group A) had simple TGA and underwent ASO within 20 days after birth while 7 (13+/-3 years; group B) had complex TGA and underwent ASO and correction of associated anomalies later after birth. Ten young, healthy adults (26+/-6 years) served as the control group.

RESULTS

Resting MBF was not different between groups. After correction for the rate-pressure product as an index of cardiac work, younger children of group A had significantly higher MBF at rest compared to healthy adults (102+/-29 vs. 77+/-6 ml/100 g/min; p = 0.012) while flow in group B was not different from the other groups (85+/-22 ml/100 g/min; p = NS). Hyperemic blood flows were significantly lower in both groups after ASO compared to normals (290+/-42 ml/100 g/min for group A, 240+/-28 for group B, 340+/-57 for normals; p < 0.01); thus, coronary flow reserve was significantly lower in both groups after ASO compared to healthy adults (3.0+/-0.6 for group A, 2.9+/-0.6 for group B, 4.6+/-0.9 for normals; p < 0.01).

CONCLUSIONS

Blood flow measurements suggest decreased coronary reserve in the absence of ischemic symptoms in children late after arterial switch repair of TGA. The global impairment of stress flow dynamics may indicate altered vasoreactivity; however, the prognostic significance of these findings needs to be determined.

A clinical comparison of arterial and atrial repairs for transposition of the great arteries: early and midterm survival and functional results

BACKGROUND

The early experience in correction of simple transposition of the great arteries (TGA) involved redirection of atrial inflow to re-establish systemic and pulmonary blood flow, the basis of the Senning and Mustard operations. Since 1984, however, the arterial switch operation (Jatene) has been increasingly used. It appears that with experience the peri-operative mortality rate for arterial repair is comparable to that for atrial repairs, while the late morbidity rates have generally favoured arterial repair, with sequelae such as obstruction of venous inflow, dysrhythmias, systemic atrioventricular valve dysfunction and impaired systemic ventricle function being more common following atrial repairs.

METHODS

A retrospective review of patients surgically treated for TGA at the Prince Charles Hospital.

RESULTS

Between April 1973 and July 1994, 103 patients with simple TGA underwent surgical correction using one of three standard approaches currently advocated (arterial switch/Jatene, Senning or Mustard operations). Fifty-one Jatene, 31 Senning and 21 Mustard operations were performed. Associated procedures included closure of ventricular septal defect, right and left ventricular outflow tract resection and pulmonary artery band removal. The coronary artery anatomy was found to be suitable in all except two patients when the Jatene operation was planned; both these patients had a Senning procedure without mortality. There were nine peri-operative deaths (4 Jatene, 2 Senning, 3 Mustard), and five late deaths (1 Jatene, 1 Senning, 3 Mustard). Follow-up was maintained to a mean time of 60.5 months (range, 9 days to 203 months). In the Jatene group there were five anastomotic stenoses (all involving the neo-pulmonary artery), three cases of arrhythmias (two postoperative supraventricular tachycardia and one nodal rhythm) and two pulmonary valve stenoses. In the Senning group there were four anastomotic stenoses (three involving pulmonary vein and one causing superior vena cava (SVC) inlet obstruction) and four cases of arrhythmias (with one requiring permanent pacemaker insertion). In the Mustard group there were two cases of SVC obstruction and two permanent pacemaker insertions for bradycardia.

CONCLUSIONS

These early and midterm results suggest that the arterial switch operation has comparable overall mortality to, and less morbidity than, the atrial repairs for TGA with the retention of left ventricle to systemic arterial connection, which may provide improved long-term results.

Long-term results of arterial switch repair of transposition of the great vessels

The arterial switch operation has become the preferred surgical procedure for transposition of the great arteries worldwide. The low operative mortality at "low-risk" institutions has been well documented. The advantages of the arterial switch compared with atrial-level repairs include a lower incidence of arrhythmias and the likelihood of normal systemic ventricular function over the long term. However, the long-term sequelae of this operation must be continually evaluated, including the fate of the supravalvular pulmonary and aortic anastomoses, growth of the aortic root, competency of the neoaortic valve, patency of the coronary arteries, effects on the conduction system, and adequacy of ventricular function. These anatomic results, as well as the neurodevelopmental outcomes of these patients, are summarized in this review. Copyright 1998 by W.B. Saunders Company

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.

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.

Reoperation after the arterial switch operation for transposition of the great arteries

Although most children after an arterial switch operation for transposition of the great arteries have normal development and cardiac function, a few require reoperation. During the last 10 years, 68 of 753 patients who underwent arterial switch operations (9.3%) underwent 75 reoperations. Thirty underwent early reoperation (< 30 days or during the same hospital stay) and 38 underwent late reoperation. Causes for reoperation included pacemaker insertion (n = 5), left diaphragm plication (n = 4), revision for hemostasis (n = 1), mediastinitis (n = 2), superior vena cava thrombosis (n = 9), subvalvular pulmonic stenosis (n = 5), supravalvular pulmonic stenosis (n = 16), residual atrial (n = 2) or ventricular (n = 8) septal defects, isolated mitral valve insufficiency (n = 2), aortic valve insufficiency (either isolated [n = 1] or in association with mitral incompetence [n = 1] or stenosis [n = 1]), left coronary artery ostial stenosis (n = 1), and recurrent aortic (n = 6) or neoaortic (n = 4) aortic coarctation. In all but 27 patients, the residual defects were already present immediately after the completion of the arterial switch operation; however, only patients with critical lesions were reoperated on early. Interventional catheterization procedures were performed when indicated; however, they only postponed inevitable reoperation. Successful relief of superior vena cava thrombosis was achieved by atriojugular bypass grafting in two patients, by early open thrombectomy in six patients, and by direct patch angioplasty of the superior vena cava once. Patch plasty for subvalvular or supravalvular pulmonic stenosis was carried out in 21 patients, septal defect closure was carried out in nine patients, and pulmonary artery banding was performed in one patient with criss-cross atrioventricular relationship and multiple ventricular septal defects. Valve repair was performed in all five patients with either isolated or combined aortic and mitral valve dysfunction. One patient with left coronary ostial stenosis underwent a patch enlargement of this ostium. Recoarctation was repaired by end-to-end anastomosis in eight patients and by a subclavian flap and a patch angioplasty in one patient each. Seven patients underwent a second reoperation for supravalvular pulmonary stenosis (n = 3), mitral valve replacement (n = 1), ventricular septal defect closure (n = 1), and recurrent coarctation (n = 2). There were six intraoperative (8.8%) and two late deaths. All early deaths occurred after early reoperations.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary angioplasty for coronary stenosis after the arterial switch procedure

Coronary balloon angioplasty seems to be an adequate therapy for proximal coronary stenoses developing after the arterial switch operation, with adequate medium-term results. Overexpansion of the lesion seems to be necessary.

Transposition of the great arteries [S,D,L]. Pathologic anatomy, diagnosis, and surgical management of a newly recognized complex

The transposition of the great arteries [S,D,L] complex is delineated for the first time from the anatomic, diagnostic, and surgical standpoints in this study of 26 cases: 16 surgical and 10 postmortem. Transposition of the great arteries with situs solitus of the viscera and atria (S), D-loop ventricles (D), and L-transposition (L) was characterized by six additional interrelated anomalies that largely determined surgical management: (1) ventricular septal defect, usually conoventricular, in 96%; (2) malalignment of the conal septum, typically leftward and posteriorly, in 80%; (3) right ventricular hypoplasia in 50%; (4) pulmonary outflow tract stenosis in 27%; (5) ventricular malposition, such as superoinferior ventricles, in 23%; and (6) absent left coronary ostium resulting in "single" right coronary artery in 23%. Complete surgical repair was done in 81% of the surgical patients with a 12.5% hospital mortality rate and no late deaths. When there was no pulmonary outflow tract stenosis and intracardiac anatomy was uncomplicated, we undertook anatomic repair before 1 month of age. However, when pulmonary outflow tract stenosis coexisted, complete repair was deferred until after age 1 year, our currently preferred operation being the REV procedure (réparation a l'etage ventriculaire). When complex intracardiac anatomy precluded biventricular repair, a palliative procedure was performed in 19% without mortality. Hence, this experience indicates that surgical management of patients with the transposition of the great arteries [S,D,L] complex is feasible.

Arrhythmias and intracardiac conduction after the arterial switch operation

Intraatrial baffling procedures such as the Mustard or Senning repair of transposition of the great arteries have been associated with a high incidence of cardiac arrhythmias. These abnormalities are thought to arise from trauma to the sinus node and atrial muscle during the procedure. In the arterial switch operation, there is little intraatrial manipulation other than the repair of the atrial septal defect. In theory, rhythm disturbances after the arterial switch operation should be less prevalent. From January 1, 1983, to December 31, 1990, 390 patients (230 with intact ventricular septum and 160 with a coexisting ventricular septal defect) underwent an arterial switch operation. Electrocardiograms and 24-hour Holter monitor studies were obtained in the 364 survivors at hospital discharge and during follow-up. Limited intracardiac electrophysiologic studies were performed 6 to 12 months after the operation.

RESULTS

Atrioventricular node function was preserved in most patients; seven patients (2%) had first-degree, two (0.7%) second-degree, and five (1.7%) had complete atrioventricular block (all with coexisting ventricular septal defect). All five patients with complete heart block received a permanent pacemaker. In those patients not having a permanent pacemaker, sinus rhythm was present in 96% on the surface electrocardiogram and 99% during 24-hour Holter monitor studies (1 month to 8.5 years, mean 2.1 years after the operation). Intracardiac electrophysiologic studies (n = 158) demonstrated normal corrected sinus node recovery times and AH intervals in 97% of patients. Atrial ectopy was present in 152 of 172 (81%) patients, with the majority (64%) of patients having only occasional premature beats without repetitive forms. Ventricular ectopy was a frequent finding during 24-hour monitoring. At hospital discharge 70% had ventricular ectopy; these values fell to 57% (in patients with intact ventricular septum) and 30% (in patients with a coexisting ventricular septal defect) at follow-up. In the early postoperative period, there were 25 episodes of supraventricular tachycardia (14 of which required therapy), 6 episodes of junctional ectopic tachycardia, and 9 episodes of ventricular tachycardia. The incidence of supraventricular tachycardia had fallen to 5% at follow-up, with no atrial flutter or fibrillation noted. Three patients had ventricular tachycardia on follow-up Holter studies. In summary, our results confirm the theoretical advantages of anatomic correction over atrial level correction of transposition of the great arteries with respect to preservation of sinus node function and low incidence of clinically significant tachyarrhythmias.

Status of the left ventricle after arterial switch operation for transposition of the great arteries. Hemodynamic and echocardiographic evaluation

BACKGROUND

The potential for improved preservation of systemic ventricular function represents an important reason for the increasing popularity of the arterial switch operation. In support of this expectation, prior studies in patients early after arterial switch operation have found normal ventricular contractility and function. This study was conducted to extend those observations to up to 10 years of follow-up and to directly examine the effects of a coexisting ventricular septal defect or short-term preparatory banding of the pulmonary artery before the arterial switch operation.

METHODS

Patients operated on from 1983 through 1991 were included. Echocardiographic and catheterization data were collected as part of a prospective evaluation of outcome in all patients who undergo the arterial switch operation at Boston Children's Hospital, with inclusion of data from the most recent catheterization only. Echocardiograms performed at least 6 months after the operation were included, with assessment of both the most recent status as well as serial trends. Whenever possible, echocardiographic evaluation included data necessary to perform analysis of ventricular mechanics including indices of afterload, preload, and contractility. Comparison was made to normal values and between subgroups defined on the basis of an arterial switch operation with or without ventricular septal defect and those who had a rapid two-stage arterial switch operation.

RESULTS

Invasive measures of left and right ventricular filling pressures, cardiac index, and pulmonary vascular resistance did not differ among the three groups. Overall, echocardiographic left ventricular end-diastolic dimension, wall thickness, mass, afterload (end-systolic wall stress), function (fractional shortening and rate-corrected velocity of fiber shortening), contractility (stress-velocity and stress-shortening relations), and preload were normal, and none of these variables was different between the groups with and without a ventricular septal defect. Serial evaluation indicated a slight but significant trend toward ventricular dilatation, perhaps related to a relatively high incidence of at least mild aortic regurgitation (30%). In contrast, in the rapid two-stage group the echocardiographic indices of left ventricular function (fractional shortening and velocity of fiber shortening) and contractility (stress-velocity and stress-shortening relations) were found to be mildly but significantly reduced compared with normal subjects and with the other arterial switch operation groups. Over the duration of follow-up encompassed by this study, no tendency toward progressive depression of function was seen.

CONCLUSIONS

As the length of observation after the arterial switch operation continues to increase, left ventricular size, mass, functional status, and contractility continues to be normal, with no evidence of time-related deterioration of function. As previously reported, the rapid two-stage arterial switch operation does represent a higher risk for mild impairment of myocardial mechanics.

Factors influencing early and late outcome of the arterial switch operation for transposition of the great arteries

Between January 1983 and January 1992, 470 patients underwent an arterial switch operation at our institution. An intact (or virtually intact) ventricular septum was present in 278 of 470 (59%); a ventricular septal defect was closed in the remaining 192. Survivals at 1 month and 1, 5, and 8 years among the 470 patients were 93%, 92%, 91%, and 91%, respectively. The hazard function for death (at any time) had a rapidly declining single phase that approached zero by one year after the operation. Risk factors for death included coronary artery patterns with a retropulmonary course of the left coronary artery (two types) and a pattern in which the right coronary artery and left anterior descending arose from the anterior sinus with a posterior course of the circumflex coronary. The only procedural risk factor identified was augmentation of the aortic arch; longer duration of circulatory arrest was also a risk factor for death. Earlier date of operation was a risk factor for death, but only in the case of the senior surgeon. Reinterventions were performed to relieve right ventricular and/or pulmonary artery stenoses alone in 28 patients. The hazard function for reintervention for pulmonary artery or valve stenosis revealed an early phase that peaked at 9 months after the operation and a constant phase for the duration of follow-up. Incremental risk factors for the early phase included multiple ventricular septal defects, the rapid two-stage arterial switch, and a coronary pattern with a single ostium supplying the right coronary and left anterior descending, with a retropulmonary course of the circumflex. The need for reintervention has decreased with time. The arterial switch operation can currently be performed early in life with a low mortality risk (< 5%) and a low incidence of reintervention (< 10%) for supravalvular pulmonary stenosis. The analyses indicate that both the mortality and reintervention risks are lower in patients with less complex anatomy.

Coarctation developing after arterial switch repair for transposition of the great arteries

We describe 2 patients with simple transposition of the great arteries in whom coarctation of the aorta developed after uncomplicated arterial switch operation. Both patients showed no symptoms or signs of this coarctation at the time of arterial switch operation.

Myocardial perfusion, function and exercise tolerance after the arterial switch operation

OBJECTIVES

This study was conducted to determine the prevalence of myocardial perfusion abnormalities at rest and exercise and to assess exercise capacity in children after the arterial switch operation.

BACKGROUND

There have been sporadic reports of myocardial ischemia or sudden death in children after the arterial switch operation for transposition of the great arteries, possibly related to inadequate coronary perfusion due to kinking or stenosis of the translocated coronary arteries.

METHODS

Myocardial perfusion at rest and peak exercise was assessed using the scintigraphic agent technetium-99m methoxyisobutyl isonitrile (sestamibi). Exercise capacity was determined with a modified Bruce protocol. Ambulatory electrocardiographic (ECG) Holter monitoring was performed. Ventricular function, contractility and wall motion were assessed echocardiographically.

RESULTS

Twenty-three children (aged 4.2 to 7.9 years) underwent evaluation. Abnormalities were found on the rest perfusion scans in 22 children (95.6%). The left ventricular myocardium was divided into 13 segments for analysis. Of 299 rest segments, 225 (75.3%) were normal, 11 (3.7%) showed mild defects, 45 (15%) moderate defects and 18 (6%) severe defects at rest. At peak exercise, 237 segments (79.3%) were normal, 24 (8%) showed mild defects, 33 (11%) moderate defects and 5 (1.7%) severe defects. Compared with rest studies, myocardial perfusion grade at exercise was unchanged in 246 segments (82.3%), improved in 42 (14%) and worsened in 11 (3.7%). All patients had normal exercise tolerance without symptoms or ischemic ECG changes. No ventricular tachycardia was seen on Holter monitoring. All patients had a shortening fraction > or = 27%. Left ventricular contractility was normal in 12 children in whom it was assessed. Regional wall motion was normal in 17 children with adequate echocardiographic images for this analysis.

CONCLUSIONS

Myocardial perfusion scan abnormalities assessed by technetium-99m sestamibi are common after an arterial switch operation. These abnormalities are of uncertain clinical significance and generally lessen with exercise. The normal exercise tolerance without symptoms or ECG changes suggests that myocardial perfusion is adequate during the physiologic stress of exercise in children up to 8 years after an arterial switch operation.

Arterial Switch for Repair of Simple and Complex Transposition of Great Arteries in a New Unit

Between January 1987 and October 1992, 11 neonates and 2 infants (12 males and 1 female) underwent arterial switch operation (ASO). There were 9 simple transpositions of great arteries (TGA), 3 TGA with ventricular septal defect (VSD), and 1 double outlet of right ventricle (Taussig-Bing) with TGA. There were 12 cases of patent ductus arteriosus (PDA) and 6 cases of atrial septal defect (ASD). Nine patients had Yacoub type A coronary pattern, 3 had type B, and 1 had type D. The neonates' mean age was 15.5 days (one 120 days old and one 22 months old). The average body weight of the neonates was 4.2 kg. The Lecompte maneuver was performed on all patients. The average bypass time was 187.8 min, and mean aortic cross-clamp time was 76.2 min, with a mean circulatory arrest time of 10 min in 6 cases. Early hospital mortality was 15.4% (2 deaths)—1 patient died during operation from myocardial infarction, and another died postoperatively from poor heart function. All survivors experienced early postoperative heart failure and needed temporary inotropic support. One patient was lost to follow-up. The other 10 patients were free from any cardiac symptoms at follow-up, with good left ventricular function. Mild to moderate aortic regurgitation and stenosis and the same in the pulmonary valve were seen on echocardiogram. Seventeen months after ASO, 1 patient required reoperation for severe postoperative pulmonary stenosis. We concluded that ASO can be performed with an acceptable mortality rate in a new unit with no previous experience of such surgery.

Late death after arterial switch operation for transposition of the great arteries

Fifty-nine patients survived for more than 1 month after an arterial switch operation (ASO). Diagnoses in these patients included transposition of the great arteries in 27, transposition of the great arteries with ventricular septal defect in 28, and double-outlet right ventricle in four. There were six late deaths (10%) during the follow-up period, and all of them occurred suddenly and unexpectedly. Four of the six late deaths were in patients who had undergone ASO in the neonatal period. Late deaths occurred from 40 days to 10 months after the operation. Autopsies were performed in all six patients. The cause of these late deaths was acute myocardial infarction. Five patients died of subendocardial infarction resulting from stenosis of the left main coronary artery. On pathologic examination, a fibrocellular intimal thickening was noted at the proximal region of the right and left coronary arteries, which resulted in 80% stenosis on average.

Role of balloon atrial septostomy before early arterial switch repair of transposition of the great arteries

Preoperative balloon atrial septostomy is the standard therapy for babies with uncomplicated cyanotic dextrotransposition of the great arteries despite the effectiveness of prostaglandin E1 infusion in alleviating systemic hypoxemia and the reported success of arterial switch repair during the 1st weeks after birth. The clinical records and echocardiographic findings of 23 infants (mean birth weight +/- SD 3.3 +/- 0.5 kg) with uncomplicated transposition of the great arteries were analyzed. Fifteen infants (Group I) did not undergo septostomy, and 8 (Group II) underwent septostomy. Before prostaglandin infusion, mean arterial oxygen tension (Po2) in Group I (26 mm Hg) did not differ from that in Group II. After prostaglandin infusion, Po2 increased significantly in Group I (43 +/- 8 mm Hg, p less than 0.001) but not in Group II despite a widely patent ductus and predominant left to right ductal shunt in all. After septostomy, Po2 increased significantly (43 +/- 4 mm Hg, p less than 0.03), and did not differ from that in Group I. Echocardiographic features generally demonstrated a nonrestrictive foramen ovale in Group I and a restrictive foramen ovale in Group II. The latter was associated with persistent hypoxemia after prostaglandin. Thus, the diameter of the foramen ovale was the primary factor influencing arterial oxygenation during prostaglandin infusion. Babies underwent the arterial switch operation at a mean age of 70 +/- 65 h with an overall survival rate of 96%; there was only one postoperative death (Group II). Absence of septostomy had no negative influence on any postoperative variable, including duration of ventilatory and inotropic support, time to discharge, or mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the Damus-Kaye-Stansel operation in infancy

Thirteen patients, 12 of whom younger than 2 years, underwent a Damus-Kaye-Stansel procedure for complete transposition of the great arteries, ventricular septal defect, or double-outlet right ventricle and subpulmonary ventricular septal defect. In 6 patients, associated cardiac anomalies caused systemic flow obstruction. There were six hospital deaths (mortality rate, 42%). In a mean follow-up period of 57 months, 5 of 7 survivors required relief of right ventricular hypertension through conduit replacement or enlargement (4 patients) or conduit valve balloon dilation (1 patient). The aortic valve became regurgitant in 2 patients in whom it had been left in potential connection with the right ventricle. One patient has moderate pulmonary valve regurgitation. The main advantage of the Damus-Kaye-Stansel procedure is that it avoids coronary relocation; also, the spatial relationship of the great arteries and the coronary anatomy do not affect its feasibility. One drawback is the need for a conduit in infancy. Our present indication for Damus-Kaye-Stansel procedure is confined to double-outlet right ventricle with subpulmonary ventricular septal defect; 5 of 6 patients survived repair in this series. Possible indications are for patients with associated subaortic obstruction or unusual coronary arrangements. Fresh or cryopreserved homografts as extracardiac conduits and primary closure of the subaortic area may reduce the need for reoperation after Damus-Kaye-Stansel procedure.