The morphologic variations of pulmonary atresia with intact ventricular septum: guidelines for surgical intervention

Transcatheter Approach for Critical Pulmonary Stenosis or Pulmonary Atresia with Intact Ventricular Septum in Young Infants Using the Simmons Catheter

Methods and Results

We retrospectively reviewed 52 young infants, 41 of whom had CPS and 11 had PA/IVS, in a single center from June 2009 to October 2017. Patients were divided into three groups according to the type of catheter used to enter through the RVOT. The unique structure of the Simmons catheter allowed it to be maneuvered directly into the RVOT within a few minutes. Compared with the other two groups, the Simmons catheter group had a significantly shorter fluoroscopy time entering through the RVOT (P < 0.001) and a shorter total X-ray exposure time (P < 0.001). Furthermore, compared with the floating catheter group, the success rate of surgery was much higher in the Simmons catheter group (P < 0.001).

Conclusions

The Simmons catheter is a safe and effective method to enter through the RVOT in infants with CPS or PA/IVS. Therefore, the Simmons catheter could be an alternative catheter when entering through the RVOT in young infants, especially neonates with low birth weight.

Critical care outcomes in pulmonary atresia and intact ventricular septum undergoing single-ventricle palliation

OBJECTIVE

To examine early outcomes for pulmonary atresia with intact ventricular septum undergoing single-ventricle palliation and to determine risk factors for mortality.

DESIGN

Retrospective observational study.

SETTING

Tertiary paediatric critical care unit.

INTERVENTION

Risk factors for mortality were sought for infants after the primary intervention whether surgical shunt or ductal stent.

MEASUREMENTS AND MAIN RESULTS

We reviewed outcomes of 19 infants with pulmonary atresia with intact ventricular septum undergoing single-ventricle palliation between July, 2000 and July, 2008. Echocardiograms, cardiac catheterisation findings, anaesthesia, and critical care management, as well as autopsy reports were reviewed. We modelled survival after surgery and looked for predictors of early mortality. A total of 19 infants underwent single-ventricle palliation and seven of these died. The risk of death was increased by a lower arterial pH at induction of anaesthesia (p = 0.01), a lower systolic blood pressure (p = 0.01), and technical problems during surgery (p = 0.03). On admission to the critical care unit, a lower mixed venous saturation (p = 0.02) and presence of tachyarrhythmia (p = 0.02) were associated with the need for mechanical support within the first 48 hours.

CONCLUSIONS

There is a high early mortality for those who undergo single-ventricle palliation. It is higher for those who are haemodynamically compromised before surgery; technical problems, and haemodynamic instability during surgery also increase mortality.

The prevalence of coronary arterial abnormalities in pulmonary atresia with intact ventricular septum and their influence on surgical results

BACKGROUND

The relatively high mortality in patients with pulmonary atresia and intact ventricular septum may be related to the presence of significant coronary arterial anomalies. This retrospective review of cineangiocardiograms was undertaken to further elucidate the types and variety of such coronary arterial abnormalities, and to assess their effect on postoperative survival.

MATERIAL AND RESULTS

Details regarding coronary arterial anatomy and abnormalities were assessed in 116 patients. We noted the site and severity of lesions, and the presence of fistulous communications from the right ventricle to the coronary arteries, assessing the proportion of left ventricular myocardium affected by coronary arterial interruptions or significant stenoses, in other words, the amount dependent on coronary circulation from the right ventricle. We also measured diameters of the tricuspid and mitral valves. Fistulas were found in 87 patients (75%), interruptions of major coronary arteries in 40 patients (34%), lack of connections between the coronary arteries and the aorta in 18 patients (16%), and single origin of a coronary artery, with the right coronary artery arising from the left, in 6 patients (5%). We found increased mortality in 47 patients (40%) who had a right ventricular-dependent coronary arterial circulation. The presence of fistulas in itself was not associated with higher mortality, but the presence of coronary arterial interruptions (p = 0.05), and a higher myocardial score (p = 0.0009), were.

CONCLUSION

We encountered a higher prevalence of both coronary arterial abnormalities and right ventricular-dependent circulation than previously reported. Awareness of the severity of the coronary arterial abnormalities should assist in planning treatment.

Pulmonary atresia with intact ventricular septum: management of, and outcomes for, a cohort of 210 consecutive patients

OBJECTIVES

We sought to determine trends, and outcomes, for a cohort of patients with pulmonary atresia with intact ventricular septum born between 1965 and 1998.

BACKGROUND

Pulmonary atresia with intact ventricular septum is a complex lesion that remains a therapeutic challenge, particularly regarding the suitability for biventricular repair.

METHODS

We identified 210 consecutive patients, and reviewed their medical records, initial angiograms, and echocardiograms, along with the relevant surgical and pathology reports.

RESULTS

The mean initial Z-score for the diameter of the tricuspid valve was -0.99 +/- 1.95, with Ebstein's malformation in 8%. A right ventricular dependent coronary arterial circulation was found in 23%. The proportion of patients who received treatment increased over time, although placement of an arterial shunt was the predominant initial procedure throughout the experience. At the last follow-up, 107 patients had not reached the planned final stage of their repair, and 79% of these had died. Of the 103 reaching the final stage of planned repair, 58 had undergone attempted biventricular repair, with 34% dying; 14 had undergone attempted one and a half ventricular repair, with 7% dying, and 31 had undergone attempted functionally univentricular repair, with 10% dying. Overall, survival was 57% at the age of 1 year, 48% at 5 years, and 43% at 10 years. Survival improved over time, with survival of 75% at 1 year, and 67% at 5 years, for patients born between 1992 and 1998. An earlier date of birth, the presence of Ebstein's malformation, and prematurity were all significant independent factors associated with decreased survival. A greater severity of coronary arterial abnormalities was significantly associated with a greater likelihood of left ventricular dysfunction during follow-up.

CONCLUSIONS

The outcomes for patients born with pulmonary atresia with intact ventricular septum have improved over time, albeit that careful initial management, and better selection, is still indicated for those planned to undergo biventricular repair.

Percutaneous balloon valvotomy in pulmonary atresia with intact ventricular septum: impact on patient care

BACKGROUND

Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare congenital lesion with high mortality. Therapy was exclusively surgical until recently, when the use of radiofrequency-assisted perforation of the atretic valve was introduced as a treatment option. This study analyzes the outcomes and morphological changes to right heart structures after percutaneous perforation and balloon dilation of the atretic valve.

METHODS AND RESULTS

Between April 1992 and August 2000, 30 patients with PA-IVS underwent attempted percutaneous valve perforation and balloon dilation of the pulmonary valve. Longitudinal echocardiographic measurements of the tricuspid valve diameter, right ventricular length and area were recorded. Z scores were calculated according to published formulas. Perforation was achieved in 27 patients. In 14 patients a modified Blalock-Taussig shunt was performed between 2 and 24 days after valve dilation. There were 3 early and 2 late deaths. Among the survivors (follow-up time of 1 to 87 months), 16 patients had a biventricular circulation, 3 a 1(1/2)-ventricle circulation, and 1 a Fontan operation. Four patients are awaiting further palliation. There was no significant change of the tricuspid valve Z score or right ventricular length Z score with time.

CONCLUSIONS

Percutaneous balloon valvotomy is an effective treatment strategy for patients with PA-IVS provided that there is a patent infundibulum and a lack of a right ventricle-dependent coronary circulation. Despite the observation that right heart growth does not increase with body growth in early follow-up, it appears adequate to maintain a biventricular circulation in many patients.

Radiofrequency perforation in the treatment of congenital heart disease

Catheter-directed perforation of cardiac tissue with radiofrequency (RF) energy has expanded the horizon of the interventional cardiologist dealing with congenital heart disorders. The focus of the following discussion will be to detail the biophysical basis behind RF perforation and review its application in the management of congenital heart lesions.

Usefulness of the preoperative tricuspid/mitral valve ratio for predicting outcome in pulmonary atresia with intact ventricular septum

Although tricuspid valve z-scores have been used to predict outcome in pulmonary atresia with intact ventricular septum, they are statistically generated from local populations, and widespread generalization may not be appropriate. To determine if there are echocardiographic predictors of outcome that can be universally used, the records of all infants with this diagnosis since 1988 were reviewed for age, weight, type of surgery, and outcome. Preoperative and follow-up echocardiograms were reviewed for valve diameter and z-scores, and valve ratios were calculated. Thirty-six patients were divided into 2 groups: group 1 included 23 infants who had a successful biventricular repair; group 2 included the remaining 13 infants who did not have a successful repair. Preoperatively, both groups had similar ages, pulmonary, aortic, and mitral z-scores, and pulmonary/aortic ratios, but the patients in group 2 had significantly lower weight (3.5 +/- 0.6 vs 2.9 +/- 0.5 kg), tricuspid z-scores (-0.7 +/- 1.5 vs -2.3 +/- 1.2), and tricuspid/mitral ratios (0.8 +/- 0.2 vs 0.5 +/- 0.1). At similar follow-up, both groups of patients had similar weight, aortic and mitral z-scores, and pulmonary/aortic ratios, but group 2 infants had significantly lower pulmonary and tricuspid z-scores and tricuspid/mitral ratios. Compared with the preoperative echocardiograms, group 1 had significant increases only in pulmonary z-scores, and pulmonary/aortic and tricuspid/mitral ratios. Group 2 had no significant change in any echocardiographic variable. The tricuspid/mitral ratio was >0.5 in all group 1 infants, and in 6 of 13 group 2 infants (2 sepsis deaths, 4 palliations). Compared with a tricuspid valve z-score >-3, a tricuspid/mitral ratio >0.5 was a better predictor of biventricular repair. Thus, infants who have a successful biventricular repair have significantly greater preoperative weight, tricuspid valve z-scores, and tricuspid/mitral valve ratios. A tricuspid/mitral ratio >0.5 was the best predictor of a biventricular repair.

Outcomes of transcatheter valvotomy in patients with pulmonary atresia and intact ventricular septum

The results of transcatheter valvotomy in pulmonary atresia with intact ventricular septum (PA-IVS) patients are presented with an attempt to identify the predictive factors for pulmonary valvotomy alone as definitive treatment. Between June 1995 and December 1997, 14 PA-IVS neonates with tripartite right ventricle underwent an attempted pulmonary valvotomy. For perforation of the pulmonary valve, a guidewire was used in 4, and a radiofrequency guidewire in 10 patients. Two outcome groups were identified. Group I included those in whom transcatheter treatment achieved a definitive success; group II patients required surgery despite an initial successful valvotomy. The attempt failed in 3 patients, 1 of whom had pericardial effusion. Perforation of the pulmonary valve was achieved in 11 patients: 2 with a guidewire and 9 with a radiofrequency guidewire. A subsequent balloon valvuloplasty was performed in these 11 patients. After valvuloplasty, mean right ventricular pressure decreased from 124 +/- 24 to 60 +/- 15 mm Hg (p <0.01). One died of heart failure and infection 10 days later, despite successful weaning from prostaglandin E1. Group I patients (n = 6) were treated with transcatheter valvotomy alone. Group II patients (n = 4) required right ventricular outflow patch. Significant differences between the 2 groups (group I vs II) were identified in tricuspid valve Z value (0.52 +/- 0.37 vs -1.25 +/- 0.48, p <0.05), pulmonary valve Z value (-3.47 +/- 0.59 vs -5.43 +/- 0.94, p <0.05), and ratio of right-to-left ventricular area on the apical 4-chamber view (0.73 +/- 0.06 vs 0.49 +/- 0.03, p <0.05). There were no significant differences in hemodynamic characteristics between the 2 groups. After a follow-up period ranging from 7 to 35 months (mean 18 +/- 10.3), the most recent echocardiograms in the 10 patients showed a mean pressure gradient across the pulmonary valve of 17 +/- 15 mm Hg. All 10 patients had an oxygen saturation of >92%. Transcatheter valvotomy using a radiofrequency guidewire is a safe and effective treatment in selected patients with PA-IVS. Transcatheter valvotomy can be a definitive treatment in PA-IVS patients with a tricuspid valve Z value > or = -0.1, pulmonary valve Z value > or = -4.1 and ratio of right-to-left ventricular area > or = 0.65.

Right ventricular function in congenital heart disease: pressure and volume overload lesions

The right ventricle is often subject to both pressure and volume overload in congenital heart disease. Evaluating right ventricular function in both the native lesion and after surgery in light of these loading conditions, presents a unique challenge for investigators studying these misshapen hearts. The purpose of this article is to briefly delineate what is generally known about right ventricular function in congenital heart disease and to touch on some noninvasive imaging modalities which have helped shed some light on this matter.

Influence of right heart size on outcome in pulmonary atresia with intact ventricular septum

BACKGROUND

Neonates with pulmonary atresia and intact ventricular septum (PA-IVS) are frequently born with hypoplastic right heart structures that must grow after right ventricular decompression (RVD) procedures for a complete two-ventricle physiology to be achieved. Previous authors have asserted that neonatal right heart size or morphology will predict right heart growth potential. Since 1983, our bias has favored early RVD regardless of initial right heart size. In 1986, we recognized a subset of patients with coronary artery abnormalities associated with poor outcome after RVD and have defined these patients as having a right ventricular-dependent coronary circulation (RVDCC).

METHODS AND RESULTS

To assess the influence of right heart size on outcome independent of the presence of RVDCC, we measured echocardiographic right ventricular (RV) dimensions in 37 neonates with adequate studies presenting between 1983 and 1990. Coronary artery anatomy was adequately assessed by angiography in 36. RV volume and tricuspid valve (TV) diameter were significantly smaller in patients with RVDCC than in those without. However, there was no statistically significant association between RV volume or TV diameter and survival among patients with or without RVDCC: Among 29 patients without RVDCC, 23 of 24 (95.8%) who achieved RVD are alive compared with 1 of 5 (20%) who did not achieve RVD (P = .001). Twenty-one of the 23 survivors have a complete two-ventricle physiology with low right atrial pressure. Among 7 patients with RVDCC, 2 patients who underwent RVD died early of left ventricular failure, whereas 4 of 5 who did not undergo RVD have survived single ventricular palliation.

CONCLUSIONS

Small right heart size is associated with RVDCC but is not associated with survival in PA-IVS. Patients without RVDCC have improved survival after RVD regardless of neonatal right heart size.

Diagnosis and management of right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum

BACKGROUND

Coronary artery anomalies including 1) right ventricle (RV)-to-coronary artery fistulas, 2) coronary artery stenoses, and 3) coronary occlusions occur in patients with pulmonary atresia with intact ventricular septum (PA-IVS). In some, a large part of the coronary blood supply may depend on the RV. This RV-dependent coronary circulation may determine survival after right ventricular decompression (RVD): RVD may cause RV "steal" in the presence of fistulas alone and ischemia, coronary isolation, or myocardial infarction in the presence of coronary stenoses.

METHODS AND RESULTS

Eighty-two patients with PA-IVS who presented between January 1979 and January 1990 were reviewed; 26 (32%) had RV-to-coronary artery fistulas. Of these 26, 23 had adequate preoperative coronary angiograms for analysis. RVD was achieved in 16. Seven of 16 had fistulas only; each survived RVD. Six of 16 had stenosis of a single coronary artery [left anterior descending coronary artery (LAD), four; right coronary artery (RCA), two]; four of six survived RVD. Three of 16 had stenoses and/or occlusion of both the RCA and LAD; all three died shortly after RVD of acute left ventricular dysfunction.

CONCLUSIONS

1) Potential RV steal alone does not preclude successful RVD. 2) Fistulas with stenoses to a single coronary artery may not preclude successful RVD. 3) RVD appears to be contraindicated in the presence of stenoses and/or occlusion involving both the right and left coronary systems. Nonsurvival after RVD seems to depend on the amount of the left ventricular myocardium at risk, i.e., that which is distal to coronary artery stenoses, especially when involvement of both coronary arteries limits effective collateralization. Precise definition of coronary arterial anatomy is mandatory in neonates with PA-IVS.

Balloon valvuloplasty after pulmonary valvotomy for babies with pulmonary atresia and intact ventricular septum

During a 2 1/2-year period, staged procedures of transventricular closed pulmonary valvotomy followed by balloon valvuloplasty were attempted in 12 babies with pulmonary atresia and an intact ventricular septum. All babies immediately underwent valvotomy when echocardiography revealed a tripartite right ventricle with adequate inflow and outflow dimensions and without sinusoidal-coronary arterial fistulas. After valvotomy, the overall mortality rate was 25% (3/12), but the only surgical death (1/12, 8%) was due to failure to establish continuity between the right ventricular cavity and the pulmonary trunk. The other 2 babies died of neonatal complications after successful valvotomy. Angiocardiography performed 5 to 18 months after valvotomy documented substantial growth of the right ventricular inflow and outflow dimensions in the 9 survivors. Twelve balloon dilation procedures were then performed in 7 babies. All except 1 achieved a significant drop in the right ventricular to left ventricular peak systolic pressure ratio (0.96 +/- 0.40 to 0.56 +/- 0.28; p less than 0.01). Balloon valvuloplasty was not required in 1 baby and failed in the other, who then underwent successful right ventricular outflow tract reconstruction. After these staged procedures, follow-up at 1 month to 20 months (mean follow-up, 14.8 months) revealed resting cyanosis in 3 babies, which was related to severe residual infundibular stenosis (55 mm Hg) in 1 and a subnormal tricuspid valve annulus in 2. The remaining 5 babies (including 1 who required no valvuloplasty) were active and pink (saturation greater than 97%) and had a mean Doppler estimated gradient of 19 mm Hg (range, 8 to 36 mm Hg) across the pulmonary valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic assessment of neonates with pulmonary atresia and intact ventricular septum

In this prospective study, 27 consecutive neonates suspected to be suffering from pulmonary atresia and intact ventricular septum underwent detailed two-dimensional echocardiographic examination before cardiac catheterization. Of the 27 neonates 25 had pulmonary atresia and intact ventricular septum and the remaining 2 had "functional pulmonary atresia" secondary to severe Ebstein's anomaly of the tricuspid valve. In all 25 neonates with pulmonary atresia and intact ventricular septum, the diagnosis and right ventricular morphology based on the tripartite approach were correctly established by echocardiography. The associated Ebstein's anomaly in two babies with pulmonary atresia and intact ventricular septum was also correctly identified by echocardiography. Among the five babies who had a sinusoidal-coronary artery communication, echocardiography demonstrated the fistula in one and provided clues for its diagnosis in two others. In the 25 neonates with pulmonary atresia and intact ventricular septum, the echocardiographic dimensions of their tricuspid anulus, right ventricular infundibulum and main pulmonary artery correlated well with the angiocardiographic measurements (r greater than 0.8). The results of this study suggest that, in the management of neonates with pulmonary atresia and intact ventricular septum, preoperative evaluation by echocardiography is usually sufficient and cardiac catheterization should be reserved for selected cases.

Anomalous origin of single coronary artery in association with pulmonary atresia

We report a case of pulmonary atresia with intact septum associated with single coronary artery which originated from the pulmonary trunk. The combination of stenotic pulmonary trunk with presence of right ventricular to coronary artery fistulous connections probably impaired myocardial perfusion after birth.

Management of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum with a small or hypoplastic right ventricle

Twenty-one neonates and infants less than 3 months old undergoing cardiac surgery for an obstructed right ventricular outflow tract, intact ventricular septum and a small or hypoplastic right ventricle were retrospectively analyzed, in order to assess the effects of a change in management protocol. Seven of the 8 patients with critical pulmonary stenosis survived surgery using a transannular outflow patch, whereas only 1 of the 8 patients with pulmonary atresia survived the same operation. Two patients in the latter group died 2 and 3 months after surgery but with complications arising from surgery. Of 5 patients with pulmonary atresia who had a modified Blalock Taussig shunt, 3 patients survived the surgery and were discharged home. These results significantly indicate that there is an unacceptably high mortality for the relief of pulmonary atresia (with intact septum) using a transannular outflow patch, and a Blalock Taussig shunt is the preferred operation. The transannular outflow patch is a safe operation for neonates with critical pulmonary stenosis, irrespective of the size of the right ventricle.

Coronary arterial abnormalities in pulmonary atresia with intact ventricular septum

The incidence and severity of abnormalities of the coronary arteries were evaluated in 35 necropsy patients with pulmonary atresia and an intact ventricular septum. Right ventricular to coronary artery fistulous connections were found in more than 60% of the cases. All patients with fistulous connections had histologic abnormalities of the coronary arteries. In 50% the lesions were mild, with medial and intimal thickening producing up to moderate luminal stenosis. In 50% there was loss of normal arterial wall structure and severe narrowing or obliteration of the arterial lumen. The coronary arterial fistulas and histologic abnormalities were prevalent in those with underdevelopment of the tricuspid valve and right ventricular cavity but were not found in patients with a normal or dilated tricuspid valve anulus. The coronary arterial abnormalities were found in more than 80% of patients with a tricuspid valve/mitral valve ratio less than 1. A single coronary artery occurred in 6 patients (17%) of this series. In 80% of those with 1 coronary artery arising from the other, the aberrantly arising coronary artery crossed anteriorly to the pulmonary artery and could be at risk in surgical attempts to reconstruct the right ventricular outflow. Aortography is recommended if the coronary arteries are not clearly delineated on ventricular cineangiocardiography.

Surgical treatment of pulmonary atresia with intact ventricular septum

A concept of management of pulmonary atresia in infancy has been presented. The basic theme employed is that pulmonary valvotomy or an outflow patch should be applied to most infants so that a biventricular heart is achieved in as many children as possible. Clearly, a functioning right ventricle cannot result in all instances and systemic to pulmonary shunts have an important adjunctive and sometimes primary therapeutic role. Our ability to judge right ventricular capability has been improved by preoperative assessment of segmental cavitary hypoplasia by noninvasive echocardiography and angiographic techniques.

Anatomical-echocardiographic correlations in pulmonary atresia with intact ventricular septum. Use of subcostal cross-sectional views

Cross-sectional echocardiographic images from 26 patients presenting pulmonary atresia with intact ventricular septum were compared with anatomical findings in specimens having the same anomaly. The echocardiographic study was based on a subcostal approach using oblique projections, and specimens were cut in the same planes. Patients were classified into three groups. In the first group the morphologically right ventricle was represented by all of its three component parts: inlet, trabecular and outlet (12 cases). The second group was made up of patients with overgrowth of the apical component. Consequently the right ventricle had only two effective components: inlet and outlet (6 cases). In the third group, muscular overgrowth of both outlet and apical portions meant that the right ventricle was represented only by an inlet portion (8 cases). The good morphologic assessment and correlation with anatomic cuts, obtained in particular by using the "right oblique equivalent" view can avoid invasive study in this malformation prior to palliative surgery.

Comprehensive management of pulmonary atresia with intact ventricular septum

The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with or without conventional surgical intervention. Therefore, a comprehensive program of medical and surgical treatment is necessary to improve long-term outlook for these infants. Such a program consists of management of the neonate at initial presentation with prompt administration of prostaglandins and institution of a combination of surgical procedures (isolated pulmonary valvotomy, valvotomy plus modified Blalock-Taussig shunt, Blalock-Taussig shunt plus balloon atrial septostomy, or Blalock-Taussig shunt alone) depending on the results of morphological analysis of the right ventricle; this treatment regimen is designed to relieve hypoxemia, encourage right ventricular growth, and provide adequate egress of blood from the right atrium. Another important element of management is to perform follow-up hemodynamic and angiographic studies when the patient is between 6 and 12 months old to ensure that the objectives of the comprehensive program are being met. Finally, a definitive repair should be offered. This can be done by using or bypassing the right ventricle, depending on whether it can support the pulmonary circuit.

Two-dimensional echocardiographic evaluation of right ventricular size and function in newborns with severe right ventricular outflow tract obstruction

Critical pulmonary stenosis or atresia with intact ventricular septum represents a congenital cardiac lesion for which the long-term prognosis appears to depend partly on the size of the right ventricle. Thus, the capability of noninvasive assessment of right ventricular size to predict operative outcome was examined in 15 infants (aged 1 to 30 days, mean 5.6) with severe right ventricular outflow tract obstruction (either critical pulmonary stenosis [7 patients] or pulmonary atresia with intact ventricular septum [8 patients]). Using echocardiography in two orthogonal subxiphoid views, right ventricular volume, wall thickness, area change fraction, ejection fraction and tricuspid anulus dimension were measured. All patients with a normalized right ventricular enddiastolic volume of less than 5 ml/m2 and a normalized tricuspid anulus dimension of less than 1.0 cm/m2/3 required a shunt operation. Only one patient with a volume of more than 6 ml/m2 and a normalized tricuspid anulus dimension of more than 1.4 cm/m2/3 required more than relief of right ventricular outflow tract obstruction. In this patient, residual severe pulmonary stenosis necessitated the shunt procedure. One patient with a volume of more than 6 ml/m2 had an anulus diameter of less than 1.4 cm/m2/3 and one patient with an anulus diameter of more than 1.4 cm/m2/3 had a volume of less than 6 ml/m2; both required shunt procedures. It therefore appears that if either the ventricular volume or tricuspid anulus size is excessively small, a shunt procedure is necessary. Wall thickness, area change fraction and ejection fraction measurements were not significantly correlated with right ventricular volume or postoperative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)