Pulmonary Outflow Tract Obstruction Research Articles

Tetralogy of Fallot: Yesterday and Today

Tetralogy of Fallot (TOF) is a cyanotic congenital cardiac defect that was first described by Stenson in 1672 and later named for Fallot, who in 1888 described it as a single pathological process responsible for (1) pulmonary outflow tract obstruction, (2) ventricular septal defect (VSD), (3) overriding aortic root, and (4) right ventricular hypertrophy. The surgical history of TOF began with the development of the systemic to pulmonary artery shunt (BT shunt) by Blalock, Taussig, and Thomas in 1944. Ten years later complete repair of TOF was performed by Lillehei using cross-circulation and by Kirklin with a primitive cardiopulmonary bypass circuit. Notable contributions by several other surgeons including Bahnson, Ebert, Malm, Trusler, Barratt-Boyes, and Castaneda would lead us into the modern era of surgery. Today, complete repair of TOF is performed before six months of age with low mortality (<2%). In select cases a modified version of the BT shunt is still performed as the initial procedure. Long-term survival rates are excellent (85%-90%). Adult survivors with TOF are an ever-increasing population and may require reintervention, surgically or catheter based. Promising future innovations include percutaneous pulmonary valve replacement, tissue-engineered autologous valves and conduits, and genetic manipulation. This article presents a review of TOF, including the history of surgical treatment, present-day approaches, and long-term outcomes.

The First Stella Van Praagh Memorial Lecture: The History and Anatomy of Tetralogy of Fallot

Stella Van Praagh, MD (1927-2006) of Children's Hospital Boston was one of the greatest pediatric cardiologists and pediatric cardiac pathologists of the 20th and early 21st centuries. Née Stella Zacharioudaki from Crete, Greece, in addition to her stellar professional attainments, she was also an outstanding cuisinière, hostess, linguist, philosopher, and philanthropist. In 1962, she married Richard Van Praagh, MD, beginning a life-long collaboration that was in every sense an affaire de coeur. They had three children and seven grandchildren. Dr Stella was the author of more than 110 scientific publications which helped to clarify the pathologic anatomy, the clinical and laboratory diagnosis, and often the surgical management of many different forms of congenital heart disease, including dextrocardia, single ventricle, truncus arteriosus, tetralogy of Fallot (TOF), transposition of the great arteries, double-outlet right ventricle, sinus venosus defect, anomalous pulmonary venous drainage, the heterotaxy syndromes with asplenia or polysplenia, juxtaposition of the atrial appendages, and apical muscular ventricular septal defect. In 1999, Dr Stella Van Praagh received the Distinguished Achievement Award of the Society for Cardiovascular Pathology, and in 2004, she was honored with the Paul Dudley White Award of the American Heart Association. Dr. Stella Van Praagh was that vanishingly rare combination of brilliant clinician, internationally renowned medical scientist, and deeply cultivated humanist. The anomaly now known as the TOF was first described by Niels Stensen in 1671, with other early reports by Edouard Sandifort (1777), William Hunter (1784), and many others. In 1888, Etienne-Louis Arthur Fallot published five serialized contributions in Marseille Médical concerning what he called the "blue malady," in which he described the now classical tetralogy of pulmonary outflow tract obstruction, ventricular septal defect, aortic overriding, and right ventricular hypertrophy. The other outstanding feature of Fallot's report was its emphasis on clinicopathologic correlation. In 1924, Maude Abbott coined the term "tetralogy of Fallot." In 1970, Van Praagh and colleagues presented the concept that the TOF is basically just one anomaly, a failure of normal expansile growth of the subpulmonary infundibulum and its sequelae. The anatomy of TOF is presented angiocardiographically, diagrammatically, and anatomically. A morphometric study of typical neonatal TOF is presented, based on 16 autopsied heart specimens with age-matched normal controls. The morphometric study documents that TOF is characterized by a low-volume subpulmonary infundibulum. The diagnostic and surgical significance of these findings is highlighted. Two rare and recently discovered forms of TOF are presented: tetralogy {S,D,I}, and tetralogy {I,D,S}. Because tetralogy {I,D,S} has atrioventricular discordance, in addition to a standard TOF repair, such patients also need an inverted (mirror-image) atrial switch operation (inverted Senning or inverted Mustard procedure). Because associated malformations can be very important to the surgical outcome of patients with tetralogy, the associated anomalies found in 100 randomly selected autopsied cases are presented.

Strategy for biventricular outflow tract reconstruction: Rastelli, REV, or Nikaidoh procedure?

Three techniques have been developed as the surgical management for patients with anomalies of ventriculoarterial connection, ventricular septal defect, and pulmonary outflow tract obstruction (stenosis): the Rastelli, Lecompte, (REV), and Nikaidoh procedures. This study was designed to compare these procedures in terms of hemodynamics of the reconstructed biventricular outflow tract, early clinical consequences, and follow-up. Between March 2004 and September 2006, a total of 30 consecutive patients underwent double root translocation procedures (modified Nikaidoh n = 11, REV n = 7, Rastelli n = 12). In the Nikaidoh procedure, both aortic and pulmonary roots were translocated. A single-valved bovine jugular vein patch was used to repair the stenotic pulmonary artery in both Nikaidoh and REV procedures. The Senning procedure was added for those with atrioventricular discordance. The Nikaidoh procedure was the most time-consuming in terms of mean cardiopulmonary bypass and aortic crossclamp times. The average mechanical ventilation time was significantly shorter in the Rastelli group (63.3 +/- 89 hours) than that in the Nikaidoh group (188.7 +/- 159 hours, P = .016), but not different from that in the REV group (76.4 +/- 112.5 hours, P = .395). Two patients in the REV group and 1 in the Rastelli group died. There were no in-hospital or late deaths in the Nikaidoh group. Postoperative echocardiography demonstrated physiologic hemodynamics in the left ventricular outflow tract and normal heart function in the Nikaidoh group. Abnormal flow pattern in the left ventricular outflow tract was noted in both REV and Rastelli groups. There were no late deaths or reoperations in any group during follow-up. The modified Nikaidoh procedure is a better surgical option for transposition of the great arteries, ventricular septal defect, and pulmonary stenosis in terms of physiologic cardiac hemodynamics. Its long-term benefits need to be evaluated with a larger number of patients and longer follow-up.

Pulmonary Artery Sarcoma Mimicking Massive Pulmonary Embolus: A Case Report

Intimal sarcomas of the pulmonary artery are rare tumors that are often difficult to distinguish from pulmonary thromboembolic disease, complicating accurate diagnosis and timely therapy. We report the case of a gentleman with a primary pulmonary artery sarcoma who presented with a massive pulmonary embolism and complete right ventricular outflow tract obstruction. The patient's condition was successfully managed with urgent pulmonary artery thromboendarterectomy, pulmonary valve replacement, and tricuspid valve annuloplasty.

Significance of Reverse Orientation of the Ductus Arteriosus in Neonates With Pulmonary Outflow Tract Obstruction for Early Intervention

Reverse orientation of the ductus arteriosus (RDA), defined as an inferior angle at the aortic junction of <90 degrees , is associated with pulmonary atresia; however, the significance of RDA in nonatretic pulmonary outflow tract obstruction (POTO) is unknown. The purpose of this study was to evaluate the relation between ductal morphology and the need for early intervention. Ductal morphology was retrospectively reviewed in 76 neonatal cases of POTO. Patients were stratified to those with conotruncal (CT) or primary pulmonary valve (PV) abnormalities. The prevalence of RDA was 40 of 68 (59%) and was higher in patients with CT defects (28 of 30, 93%) compared with PV abnormalities (12 of 38, 32%; chi-square = 26.4, p <0.0001). Early intervention was required in 29 of 40 patients with RDA (73%) compared with only 8 of 28 patients with normal ductal morphology (31%; chi-square = 12.8, p <0.001). The proportion of patients with RDA who required early intervention was greater in PV abnormalities (12 of 12, 100%) compared with CT defects (17 of 28, 61%; chi-square = 6.5, p <0.02). Importantly, after excluding patients with pulmonary atresia, these analyses were unchanged. In patients with nonatretic POTO, a threshold inferior angle of 65 degrees was predictive of the need for early intervention. RDA in patients with PV abnormalities, or CT defects and an inferior angle <65 degrees , is a specific indicator for early intervention. These findings demonstrate an association between RDA in the context of atretic and nonatretic POTO and the need for early intervention. The need for early intervention should be considered when RDA is identified in this population.

1039-200 Outcome of patients with D-transposition of the great arteries with abnormal pulmonary valve or left ventricular outflow tract obstruction following arterial switch operation

1039-200 Outcome of patients with D-transposition of the great arteries with abnormal pulmonary valve or left ventricular outflow tract obstruction following arterial switch operation

1134-204 Early intervention for pulmonary outflow tract obstruction in neonates is associated with reverse orientation of the ductus arteriosus

1134-204 Early intervention for pulmonary outflow tract obstruction in neonates is associated with reverse orientation of the ductus arteriosus

Functional acquired pulmonary atresia secondary to subpulmonary aneurysmal tissue: a rare form of pulmonary outflow tract obstruction

artery (PA) arising from rudimentary pouch (*). Fetal echocardiography was performed at 19 and 29 weeks gestation after an abnormal screening ultrasound suggested left heart hypoplasia. The echocardiogram revealed left-sided hypoplasia with d-transposition of the great arteries and a small, posteriorly positioned pulmonary artery (PA) with both prograde and retrograde flow demonstrated. There appeared to be a moderate ventricular septal defect and, of note, there was unusual aneurysmal tissue of indeterminate origin below the pulmonary annulus. Postnatal echocardiography confirmed d-transposition of the great arteries with the aorta anterior and rightward of the smaller PA. The PA arose directly from a rudimentary, aneurysmal blind pouch (Figure 1) with bidirectional flow between the blind pouch and the main PA (Figure 2). However, no communication between the pouch and the remainder of the heart could be demonstrated by Doppler interrogation. The aneurysmal pouch was centrally located in the heart and appeared to possibly consist of redundant atrioventricular (AV) valve tissue contiguous with a leaflet of the left-sided AV valve. The PA was supplied by a large, tortuous patent ductus arteriosus typical for pulmonary atresia. There were 2 distinct AV valves entering a common single ventricle, with hypoplasia of the left-sided AV valve noted. The patient was initially treated with prostaglandin infusion to maintain ductal patency, followed by placement of a right-sided Blalock-Taussig shunt in the neonatal period. She subsequently underwent successful bidirectional Glenn anastomosis and left pulmonary arterioplasty at 7 months of age. This case represents an extremely unusual form of functional pulmonary atresia in which abnormal intracardiac aneurysmal tissue of indeterminate ori-

Apico-pulmonary artery conduit repair of congenitally corrected transposition of the great arteries with ventricular septal defect and pulmonary outflow tract obstruction: A 10-year follow-up

Background In conventional repair of the congenitally corrected transpositions of the great arteries associated with ventricular septal defect and pulmonary outflow tract obstruction, the placement of the left ventricle–pulmonary artery conduit is at risk owing to probable compression by the sternum, heart block, or injury to the mitral anterior papillary muscle. Apical placement of the left ventriculotomy for the inflow conduit rather than in the midportion or base placement may avoid these complications, although this results in a long and winding extracardiac conduit that may be short-lived because of the proliferation of pseudointima. Methods Between 1985 and 1990, a nonvalved Dacron woven-fabric graft conduit was placed between the left ventricular apex and pulmonary artery in 5 patients (mean age, 6.2 ± 1.7 years) who were then followed for at least 10 years. Results No iatrogenic heart blocks or mitral regurgitation developed. All patients were complaint-free during the follow-up period, although 1 patient who was clinically well died suddenly in the 10th follow-up year. Cardiac catheterization in the 10th follow-up year indicated a pressure gradient of 21 ± 6 mm Hg across the conduit, and angiography revealed that the conduit diameter was 91% ± 6% of the original conduit diameter. Conclusions The reportedly poor early and late outcomes that occur after a conventional repair of congenitally corrected transpositions of the great arteries associated with ventricular septal defect and pulmonary outflow tract obstruction, which places an extracardiac conduit between the left ventricle and the pulmonary artery, may be partially neutralized by relocating the inflow position to the apex.

Cleft mitral valve without ostium primum defect: anatomic data and surgical considerations based on 41 cases

Background Cleft mitral valve without an ostium primum defect, referred to as isolated cleft mitral valve, has been the subject of many reports; yet its morphology and operability remain incompletely understood. Methods The anatomic findings in 36 postmortem cases, five explanted hearts, and relevant clinical data constitute the material basis of this report. Cardiac catheterization data were available in 29 cases and two-dimensional echocardiograms in 13 cases. Results Twenty cases had normally related great arteries with subpulmonary conus. Of these cases 4 (20%) had tetralogy of Fallot and 1 had tricuspid atresia. Twenty-one cases had abnormal ventriculoarterial relationships with subaortic or bilateral conus resulting in transposition in 16 (76%) and double-outlet right ventricle in 5 (24%). In the cases with normally related great arteries, the morphology of the ventricular septal defect and the mitral cleft were similar to those of the more complete forms of atrioventricular canal defects. The mitral cleft usually resulted in progressive mitral regurgitation, which can be treated by surgical closure of the cleft. In the cases with abnormal conus, the morphology of the ventricular septal defect and the mitral cleft did not resemble atrioventricular canal defects. The attachment of the cleft usually produced obstruction of the left ventricular pulmonary outflow tract. Surgical repair of the cleft cannot eliminate this obstruction. Conclusions There are two different anatomic types of isolated cleft mitral valve: the canal type, and abnormal conus type. Diagnosis of the associated ventriculoarterial relationships helps to guide their surgical treatment.

The extracardiac Fontan procedure without cardiopulmonary bypass: technique and intermediate-term results

Background The extracardiac Fontan procedure (ECF) usually requires cardiopulmonary bypass (CPB). In this report, the results and techniques of this procedure without CPB at a single institution are presented. Methods Between August 1992 and December 2001, ECF without CPB was achieved in 24 of 44 patients undergoing an ECF. Mean age at surgery was 5.9 ± 2.9 years, and mean weight was 20.7 ± 12.6 kg. Diagnoses were tricuspid atresia in 9 patients, single-ventricle with pulmonary outflow tract obstruction in 7, pulmonary atresia/intact septum in 5, and other complex single-ventricle physiology in 3. Initial palliation was by arterial to pulmonary artery shunt in 21 and pulmonary artery banding in 1. A bidirectional cavopulmonary connection was created in 23 patients. A temporary inferior vena caval–to–atrial shunt was used to complete the procedure without CPB. Median graft size was 16 mm (range 14 to 20 mm). Results There was no early mortality, and 68% of patients were discharged without complications. Complications included persistent cyanosis in 4 patients, persistent pleural effusions in 2 (one chylous), and phrenic nerve injury in 1. Median postoperative hospital stay was 16 days (range 10 to 50) days. At a mean follow-up of 44 ± 28 months, there was no conduit obstruction. One patient died 11 months postoperatively, and 1 patient received a heart transplant 26 months post-ECF. Conclusions At intermediate term follow-up, the ECF without CPB appears to be safe and technically reproducible in selected cases. Ongoing follow-up of these patients is necessary to document the theoretical advantages of avoiding CPB.

Modified Lecompte procedure for the anomalies of ventriculoarterial connection

Background. The Lecompte procedure for correcting transposition of the great arteries has an advantage because it obviates the need for an extracardiac conduit for the reconstruction of the pulmonary outflow tract. In this study, we evaluated the effectiveness and the application of the Lecompte procedure based on our experiences. Methods. A retrospective review was conducted of the records of 45 patients who underwent the Lecompte procedure during the past 11 years to achieve direct right ventricle to pulmonary artery continuity. Mean age at operation was 2.4 ± 1.7 years (range 3.5 months to 6.9 years). The diagnoses involved anomalies of the ventriculoarterial connection with ventricular septal defect and pulmonary outflow tract obstruction, such as transposition of the great arteries, double-outlet right ventricle, and double-outlet left ventricle. Results. Early mortality was 4.4% (2 of 45 patients) and late mortality was 4.7% (2 of 43). The mean follow-up was 4.9 ± 3.1 years. Fourteen patients (34.1% of survivors, n = 41) had pulmonary stenosis (pressure gradient above 30 mm Hg), the main reason for which was a calcified monocusp valve (n = 10, 71.4%). Eight of 45 patients (17.8%) underwent reoperation: 2 for residual ventricular septal defect, 1 for recurrent septic vegetation, and 5 for pulmonary stenosis. The cumulative survival rates were 91.1% ± 4.2% at 10 years. The actuarial probabilities of freedom from reoperation for pulmonary stenosis were 93.8% ± 4.3% and 71.4% ± 11.8% at 5 and 10 years, respectively. Conclusions. Our review suggests that the Lecompte procedure is an effective treatment modality for anomalies of the ventriculoarterial connection with ventricular septal defect and pulmonary outflow tract obstruction. Repair in early age is possible with acceptable morbidity and mortality, but recurrent right ventricular outflow tract obstruction caused by degeneration of the monocusp valve is a problem that needs resolution.

Congenital Heart Surgery Nomenclature and Database Project: double outlet left ventricle

Double outlet left ventricle (DOLV) is a type of ventriculoarterial connection in which both great arteries arise entirely or predominantly from the left ventricle. Although it was initially believed that bilateral absence of conus is a prerequisite for such diagnosis, all possible conal configurations have been described in this malformation. The morphology of DOLV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the right ventricle to the pulmonary circulation by an intraventricular tunnel repair connecting the VSD to the pulmonary semilunar valve. This ideal surgical therapy is not always possible, because of the presence of confounding anatomical barriers. Several alternative surgical procedures have been devised to accommodate these more complex situations. A framework for the development of the DOLV module of a pediatric cardiac surgical database is proposed.

Congenital Heart Surgery Nomenclature and Database Project: double outlet right ventricle

Double outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great vessels arise entirely or predominantly from the right ventricle. Although the presence of aortic-mitral discontinuity and bilateral coni are important descriptors, they should not serve as absolute prerequisites for the diagnosis of DORV. The morphology of DORV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the great artery relationships to each other, the coronary artery anatomy, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), the tricuspid-pulmonary annular distance, and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the left ventricle to the systemic circulation by an intraventricular tunnel repair connecting the VSD to the systemic semilunar valve. This ideal surgical therapy is not always possible due to the presence of confounding anatomical barriers. A multitude of alternative surgical procedures has been devised to accommodate these more complex situations. A framework for the development of the DORV module for a pediatric cardiac surgical database is proposed.

Staged palliation of single ventricle with Levo-transposition of the great arteries

Patients born with single ventricle and L-transposition of the great arteries present challenging medical and surgical management problems. This defect is characterized by a wide variation in cardiac morphology and physiology. The clinical spectrum can range from cyanosis due to pulmonary outflow obstruction and venoarterial shunting to congestive heart failure from pulmonary over-circulation and systemic outflow tract obstruction. To avoid major operations in ill neonates and infants, earlier surgical treatment strategies concentrated on less invasive procedures that did not require cardiopulmonary bypass. Because of relatively poor initial results and a small number of patients presenting later as good candidates for the Fontan procedure, more elaborate initial palliative operations have been used. Despite their increasing complexity, these procedures more completely address the underlying anatomic and physiologic problems and have accounted for steadily improved patient survival.

Accessory and anomalous atrioventricular valvar tissue causing outflow tract obstruction: surgical implications of a heterogeneous and complex problem.

The purpose of this study was to determine the effect of accessory or anomalous atrioventricular valvar apparatus on relief of outflow tract obstruction. Outflow tract obstruction due to accessory tissue or anomalous attachments of the atrioventricular valvar apparatus is an unusual but well-recognized problem. In addition to obstruction, anomalous attachments of the atrioventricular valvar apparatus may interfere with procedures to relieve outflow tract obstruction or perform outflow tract reconstruction. Since 1992, we have operated on 21 patients (median age 4 years) with systemic (n=13), pulmonary (n=5) or bilateral (n=3) outflow tract obstruction due to accessory atrioventricular valvar tissue and/or anomalous attachments of the subvalvar apparatus. Primary diagnoses were isolated obstruction of the systemic outflow tract or aortic arch (n=7), transposition complexes (n=6), previously repaired atrioventricular septal defect (n=3), functionally single ventricle (n=3) and ventricular septal defect with pulmonary outflow obstruction (n=2). Outflow tract gradients ranged from 20-110 mm Hg (median 58 mm Hg). Complete relief of obstruction due to atrioventricular valvar anomalies was possible in 14 patients. In six patients, the planned procedure either had to be modified or only partial relief of the obstruction was achieved. In the remaining patient, who had borderline functionally single ventricle heart disease (unbalanced atrioventricular septal defect) and systemic outflow obstruction due to accessory and functional valvar apparatus, support was withdrawn because the parents refused univentricular palliation and the valvar anomalies precluded a Ross-Konno procedure. There were two early deaths. At follow-up ranging from 1 to 66 months (median 27 months), there was one death, and there has been no recurrence of outflow tract obstruction or residual atrioventricular valvar tissue. Outflow tract obstruction caused by accessory or anomalous atrioventricular valvar structures is an uncommon and heterogeneous group of conditions that can have significant surgical implications. In the majority of cases, tailoring of surgical techniques will permit complete relief of obstruction. However, such anomalies may limit standard surgical options and necessitate an innovative approach in some patients.

Total anomalous pulmonary venous connections and consideration of the fontan or one-ventricle repair

There is now a considerable literature that babies with right atrial isomerism have a poor outcome. The reasons for this are complex and multifactorial, but may be related at least in part to intrinsically small and abnormal pulmonary veins. We reviewed a series of consecutive patients seen at a single institution and found that babies with right atrial isomerism, severe pulmonary outflow tract obstruction or atresia, and total anomalous obstructed pulmonary veins had a grim outlook, especially those requiring operation in the neonatal period. Others have reported a similarly concerning outcome.

Management and Outcomes of Right Atrial Isomerism: A 26-Year Experience

Objectives. We sought to determine, in a large series of patients with right atrial isomerism, factors associated with mortality.Background. Right atrial isomerism is associated with complex congenital heart disease and high morbidity and mortality.Method. All data from patients diagnosed with right atrial isomerism between January 1970 and March 1996 were reviewed.Results. A total of 91 consecutive patients (54 male) were identified. Most patients (89%) presented within the first month of life, 62% at birth. Cardiac abnormalities included common atrioventricular (AV) valve (81%), ventricular hypoplasia or single ventricle (73%), abnormal ventriculoarterial connections (96%), pulmonary outflow tract obstruction (84%), anomalous pulmonary venous drainage (87%) and pulmonary vein obstruction (30%). The overall mortality rate was 69%. No interventions were planned or performed in 24%, 95% of whom died. The mortality rate for patients requiring their first cardiovascular operation in the neonatal period was 75% versus 51% for those with later first operations (p < 0.05). The surgical mortality rate for patients undergoing pulmonary vein repair was 95%. Overall survival estimates were 71% at 1 month, 49% at 1 year and 35% at 5 years. Independent risk factors for decreased time to death included the absence of pulmonary outflow obstruction (relative risk [RR] 2.23, p < 0.03), presence of major AV valve anomaly (RR 5.23, p < 0.03) and obstructed pulmonary veins (RR 5.43, p < 0.0001).Conclusions. Right atrial isomerism continues to have an associated high mortality despite surgical innovations. Management of pulmonary vein obstruction remains a serious problem and is associated with high mortality.

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

To assess outcomes of anatomical repair (double switch procedure) in infants and children with congenitally corrected transposition of the great arteries. 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. 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.

Aneurysm of the membranous ventricular septum resulting in pulmonary outflow tract obstruction in congenitally corrected transposition of the great arteries

Aneurysm of the membranous ventricular septum causing subpulmonic obstruction in patients with corrected transposition is rare but well documented. Higher left-sided (morphologic right) ventricular pressure causes protrusion of the aneurysm into the pulmonary outflow tract of the right-sided morphologic left ventricle, causing obstruction related to lack of conus and proximity of the aneurysm to subpulmonary region. Echo Doppler studies and angiography are useful in making a correct diagnosis. Surgical resection of the aneurysm along with closure of the ventricular septal defect is the treatment of choice. The prognosis is likely to be excellent.