Is routine preoperative cardiac catheterization necessary before repair of secundum and sinus venosus atrial septal defects?

Between January 1976 and July 1983, 217 patients with atrial septal defect underwent surgical repair at Children's Hospital. Thirty with a primum atrial septal defect and 26 who underwent cardiac catheterization elsewhere before being seen were excluded from analysis. Of the 161 remaining patients, 52 (31%) underwent preoperative cardiac catheterization, 38 because the physical examination was considered atypical for a secundum atrial septal defect and 14 because of a preexisting routine indication. One hundred nine (69%) underwent surgery without catheterization, with the attending cardiologist relying on clinical examination alone in 5, additional technetium radionuclide angiocardiography in 5, M-mode echocardiography in 13 and two-dimensional echocardiography in 43; both M-mode echocardiography and radionuclide angiography were performed in 24 and two-dimensional echocardiography and radionuclide angiography in 19. Since 1976, there has been a trend toward a reduction in the use of catheterization and use of one rather than two noninvasive or semiinvasive techniques for the detection of atrial defects. Of the 52 patients who underwent catheterization, the correct anatomic diagnosis was made before catheterization in 47 (90%). Two patients with a sinus venosus defect and one each with a sinus venosus defect plus partial anomalous pulmonary venous connection, partial anomalous pulmonary venous connection without an atrial septal defect and a sinoseptal defect were missed. Of 109 patients without catheterization, a correct morphologic diagnosis was made before surgery in 92 (84%). Nine patients with a sinus venosus defect, three with sinus venous defect and partial anomolous pulmonary venous connection, four with partial anomalous pulmonary venous return without an atrial septal defect and one with a secundum defect were incorrectly diagnosed.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary surgical closure of ventricular septal defect in the first year of life: results in 128 infants.

Between January 1973 and July 1981, 128 patients less than 1 year of age with failure to thrive, congestive heart failure or pulmonary artery hypertension underwent primary repair of a ventricular septal defect. The hospital mortality rate was 7.8% (10 of 128), and the late mortality rate was 2.3% (3 of 128). Mortality was highest among younger infants with preexisting respiratory problems or a hemodynamically significant residual lesion postoperatively. Complications included a large residual shunt in eight (6.2%), transient neurologic problems in five (3.9%) and persistent complete heart block in three (2.3%). Lung biopsy specimens obtained from 49 patients showed pulmonary vascular abnormalities in all. Complete right bundle branch block developed in 74 (64%) and bifascicular block appeared in 11 (9%). Recatheterization in 70 patients (55%) showed normal pulmonary artery pressures in all but 2 patients with a large residual shunt. Complete closure of the defect had been achieved in 49 (70%), and a hemodynamically insignificant shunt remained in 19 (27%). Patients without significant hemodynamic residua were asymptomatic and tended to accelerate in growth after surgery.

Current results of management in transposition of the great arteries, with special emphasis on patients with associated ventricular septal defect.

Two hundred forty-five patients less than 15 days of age with transposition of the great arteries with or without a ventricular septal defect or pulmonary stenosis were entered into an ongoing 20 institution treatment study between January 1, 1985 and June 1, 1986. Complete follow-up is available on all patients. The ventricular septal defect narrowed in only 1 of 36 patients with combined transposition of the great arteries and ventricular septal defect; pulmonary stenosis developed or worsened in 3 of these 36 patients and in 3 of the 187 patients with simple transposition. Twelve month overall survival among the 245 patients was 80%. No morphologic feature of transposition was a risk factor for death but major associated cardiac and noncardiac anomalies (more common in patients with combined transposition and ventricular septal defect) and low birth weight were risk factors. Neither arterial switch repair (n = 86), atrial switch (Mustard) repair (n = 21) nor atrial switch (Senning) repair (n = 39) was a risk factor for death, but results in all surgical groups were better in the last part of the experience. Death before repair was less frequent late in the study. Possibly, in low birth weight infants, survival was better with the arterial than with the atrial switch repair. These data suggest that survival at 1 year is similar with either the arterial or the atrial switch repair. The early results of repair of combined transposition of the great arteries and ventricular septal defect are as good as those of simple transposition. Special institutional efforts are required to attain good results with the arterial switch repair and to prevent death before repair.

Tetralogy of Fallot with diminutive pulmonary arteries: preoperative pulmonary valve dilation and transcatheter rehabilitation of pulmonary arteries.

OBJECTIVES: This study sought to determine the results of a novel transcatheter management approach in tetralogy of Fallot with diminutive pulmonary arteries. BACKGROUND: Tetralogy of Fallot with diminutive pulmonary arteries and severe pulmonary stenosis is rare and resembles tetralogy of Fallot with pulmonary atresia: There is a high incidence of aortopulmonary collateral channels, arborization abnormalities, stenoses and need for multiple operations. Because a combined catheter-surgery approach facilitates repair in these patients, such an approach may benefit those with diminutive pulmonary arteries and pulmonary stenosis. METHODS: Clinical, catheterization and surgical data were studied retrospectively for 10 such patients undergoing preoperative pulmonary valve balloon dilation, among other transcatheter interventions, from January 1989 to January 1995. RESULTS: Initially, the Nakata index ranged from 20 to 98 mm2/m2 (mean 67 +/- 28 mm2/m2). The pulmonary valve was first balloon dilated (mean balloon/annulus 1.5 +/- 0.3), and the mean initial valve annulus Z score (-4.0 +/- 1) increased to -33 +/- 1.1 (p < 0.01) Other interventions included branch pulmonary artery balloon dilation (7 patients, 23 vessels) and coil embolization of aortopulmonary collateral channels (8 patients, 31 collateral channels). At preoperative follow-up catheterization, the mean pulmonary annulus Z score was -3.1 +/- 0.7, and the Nakata index increased to 143 +/- 84 mm2/m2 (p < 0.03). All patients underwent complete surgical repair successfully. At a mean follow-up period of 2.6 +/- 2 years, right ventricular pressure was < 70% systemic in all patients and < 50% systemic in seven. CONCLUSIONS: In patients with tetralogy of Fallot, severe pulmonary stenosis and diminutive pulmonary arteries, initial pulmonary valve balloon dilation increases the annulus Z score and anterograde pulmonary blood flow and facilities simultaneous coiling of aortopulmonary collateral channels and access for branch pulmonary artery dilation, all of which results in pulmonary artery growth, simplifying surgical management.

Enlarged bronchial arteries after early repair of transposition of the great arteries.

OBJECTIVES: This study was undertaken to define the incidence of enlarged bronchial arteries after early surgical repair of transposition of the great arteries by the arterial switch operation, and to report the results of catheter-directed therapy in five patients. BACKGROUND: Pathologic and angiographic studies have demonstrated enlarged bronchial arteries in patients with transposition of the great arteries. METHODS: A subjective 4-point scale was used to grade postoperative angiograms performed in 119 patients at our institution between January 1983 and December 1991. Grades 0 and 1 were designated if there was no opacification of the pulmonary arteries or veins, whereas grades 2 and 3 were assigned if there was such opacification. The median age at repair was 8 days (range 1 day to 13 months) and the median age at catheterization was 11.2 months (range 3.6 to 58.5). An intact ventricular septum was present in 84 (71%) of 119 patients. RESULTS: Significantly increased bronchial flow (grade 2 or 3) was present in 55 (46%) of 119 patients. Age at repair, age at catheterization and interval between repair and catheterization were not associated with significantly increased bronchial flow; however, an intact ventricular septum was weakly associated with increased flow (p = 0.04). Coil embolization was performed in five patients with complete occlusion of the vessels and no significant complications. CONCLUSIONS: Abnormally enlarged bronchial arteries are frequently identified at postoperative catheterization despite early repair and may explain continuous murmurs or persistent cardiomegaly in patients with otherwise normal noninvasive findings. When clinically indicated, catheter-directed therapy can be performed with good results.

Cardiac catheterization and test occlusion of the interatrial communication after the fenestrated Fontan operation.

OBJECTIVES: Our objective was to determine whether catheterization data obtained after a fenestrated Fontan operation influenced patient management or predicted functional status. BACKGROUND: Cardiac catheterization after a fenestrated Fontan operation is undertaken to identify residual lesions and to observe the patient's response to test occlusion of the baffle fenestration. METHODS: Sixty patients undergoing both a fenestrated Fontan operation before July 1991 and a postoperative catheterization before March 1992 were included in the study. Catheterization data were collected according to a test occlusion protocol; these data were reviewed, and the patient's clinical status at follow-up was ascertained. RESULTS: Test occlusion resulted in a significant increase in systemic venous pressure, arterial oxygen saturation and arteriovenous difference in oxygen content (p < 0.0001). After test occlusion, systemic venous pressure was 40% higher and systemic venous saturation 23% lower among patients with an unfavorable versus a favorable response to test occlusion, although differences between the two groups were subtle or inapparent in the baseline state. Branch pulmonary artery stenosis (identified and balloon dilated in 6 patients) and grade 2 or 3 aortopulmonary collateral vessels (identified and coil embolized in 20) were associated with elevation in systemic venous pressure (p < 0.01). After an average of 2 years of follow-up, there were no deaths, and 50 (83%) of 60 patients were in New York Heart Association functional class I. The only postoperative characteristic significantly associated with being in functional class I at follow-up was a systemic venous pressure < 17 mm Hg. CONCLUSIONS: Cardiac catheterization with test occlusion of the interatrial communication provides useful information after a fenestrated Fontan operation. Conditions associated with elevated systemic venous pressure should be sought and treated, and the response of systemic venous pressure to test occlusion should be considered when deciding whether to close an interatrial communication.

Valve replacement in children less than 5 years of age.

Between 1966 and 1984, there were 63 children less than 5 years of age who underwent 70 valve replacements (49 mitral [5 repeat], 6 aortic, 11 tricuspid [systemic ventricle; 2 repeat]), 2 tricuspid [pulmonary ventricle] and 1 multiple [mitral-aortic]) at Children's Hospital. Tissue valves were used in 20%. Since 1980, only Björk-Shiley and St. Jude valves have been used. The most common indication for valve replacement was mitral regurgitation after repair of atrioventricular (AV) canal (34%). Mortality dropped considerably over time: 76% before 1979, 33% from 1979 to 1982 and 22% since 1982. More than two-thirds of fatalities were operative deaths, usually within 3 days of surgery. Actuarial survival curves for those operated on since 1980 predict 1 and 5 year survival of 73 and 51%, respectively. For the 46 operative survivors 1 and 5 year valve survival was 97 and 70%, respectively. Postoperative hemodynamics were significantly improved on elective postoperative catheterizations. All but one patient with non-tissue valves received anticoagulant therapy. Postoperative complications included thromboembolism (1.6/100 patients-years) and hemorrhage (0.8/100 patient-years). The frequency of intravascular hemolysis and endocarditis was 1.6%, comparable with adult experience. Complete heart block requiring a pacemaker developed in nine patients (14.1%), in all after AV valve replacement. Valve replacement in young children generally results in considerable hemodynamic improvement. The mortality rate remains above that observed in adults but has declined considerably for those operated on after 1980.

Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia.

Subaortic obstruction caused by either a restrictive bulboventricular foramen in single left ventricle with an outflow chamber or by a restrictive ventricular septal defect in tricuspid atresia with transposition of the great arteries can lead to a hypertrophied, noncompliant ventricle and excessive pulmonary blood flow. This combination is disadvantageous to potential Fontan procedure candidates because they are dependent on good ventricular function and low pulmonary vascular resistance for survival. The results of surgical procedures to directly or indirectly relieve significant subaortic obstruction (gradient greater than 30 mm Hg) in 24 patients, 16 with single left ventricle and 8 with tricuspid atresia, were reviewed. Four patients had a left ventricular apex to descending aorta valved conduit; none survived. Seven patients had resection of subaortic tissue; four survived and four developed heart block at surgery. Adequate gradient relief was evident in only one of the four survivors. Thirteen patients had a main pulmonary artery to ascending aorta anastomosis or conduit; six survived. All survivors had adequate gradient relief. The overall survival was 42% (10 of 24). None of seven patients with a subaortic gradient greater than 75 mm Hg survived. These data show that: Surgical relief of established subaortic obstruction in patients with single left ventricle and tricuspid atresia carries a high mortality rate, especially if the subaortic gradient is greater than 75 mm Hg. The best procedure appears to be the pulmonary artery to ascending aorta anastomosis. A clearer understanding of the factors leading to the development of significant subaortic obstruction is necessary to prevent it or to devise improved therapeutic strategies.

Tricuspid atresia or severe stenosis with partial common atrioventricular canal: anatomic data, clinical profile and surgical considerations.

The anatomic findings in 11 cases of tricuspid atresia and in two cases of severe tricuspid stenosis, both combined with partial common atrioventricular (AV) canal, are presented in detail. Twelve cases were documented by postmortem examination and the diagnosis was confirmed by echocardiography and surgical observation in the one living patient. Clinical data available in nine cases and cardiac catheterization data obtained in eight are included in this report. In three cases (23%)--two with tricuspid atresia and one with extreme tricuspid stenosis--the tricuspid valve and right ventricle exhibited characteristics seen in Ebstein's anomaly. In all 13 cases, the great arteries were normally related. The ventricular septal defect(s) in 10 (83%) of the 12 postmortem cases rapidly became smaller and this resulted in marked diminution of the pulmonary blood flow and severe hypoxia. Only three of the eight patients with available cardiac catheterization and angiocardiographic data showed the scooped-out appearance of the left ventricular septal surface characteristic of AV canal defects. By contrast, two-dimensional echocardiography, available in the three most recent cases, accurately demonstrated all the defects present and represents the diagnostic method of choice. Early surgical intervention to establish a systemic to pulmonary artery anastomosis is essential for survival. More definitive surgical treatment can be achieved later by an atriopulmonary or cavopulmonary anastomosis with or without replacement of the cleft and often regurgitant mitral valve. The one living patient exemplifies this approach. This is the largest series of this unusual type of tricuspid atresia reported to date.

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.

Aneurysm of the pulmonary artery as a cause of severe chest pain.

A 35-year-old man came to the emergency room with severe prolonged precordial chest pain. Serial chest roentgenograms obtained over a ten-year period revealed gradual development of marked aneurysmal dilatation of the pulmonary artery. Impending rupture of the artery was feared in spite of the presence of normal pulmonary artery pressure. At surgery, a markedly dilated pulmonary artery without evidence of rupture was found and the size was reduced by aneurysmorrhaphy. Prompt and continued relief of symptoms was achieved thereafter. Severe chest pain can be an initial symptom of pulmonary artery aneurysm in the absence of rupture, such pain arising either from pain receptors in the wall of the pulmonary artery or possibly from pressure on contiguous mediastinal structures.

Hemodynamic response to high-frequency ventilation in infants following cardiac surgery.

The hemodynamic response to high-frequency ventilation was compared with conventional ventilation in six infants following cardiac surgery. While undergoing high-frequency ventilation, adequate gas exchange was maintained in all infants. High frequency ventilation allowed a reduction of peak ventilatory pressure at the airway opening by 19%, and peak tracheal pressure by 42%. No clinically important changes in heart rate, systemic and pulmonary arterial pressure, cardiac index, or systemic and pulmonary vascular resistance were noted when high-frequency ventilation was compared with conventional ventilation.

Cognitive development of children following early repair of transposition of the great arteries using deep hypothermic circulatory arrest.

Twenty-eight children who underwent corrective cardiac surgery in early infancy had developmental evaluations to explore whether cardiopulmonary bypass perfusion variables are associated with later cognitive function. All had transposition of the great arteries repaired by the arterial switch operation using deep hypothermic circulatory arrest. The mean duration of deep hypothermic circulatory arrest was 64 +/- 10 minutes (mean +/- SD). Median age at repair was 4 days (range 1 to 125 days). Tests of development were administered at age 7 to 53 months: Bayley Scales for children younger than 30 months of age (n = 18) and McCarthy Scales for older children (n = 10). Overall cognitive development score was 101.2 +/- 11.1. Duration of deep hypothermic circulatory arrest was not associated with performance. However, for core cooling periods of less than 20 minutes' duration, shorter cooling periods were associated with lower scores (r = .85, n = 11, P less than .001). These data suggest that patients undergoing relatively long periods of deep hypothermic circulatory arrest may require some minimum time of cardiopulmonary bypass cooling to avoid central nervous system injury.

Comparison of technetium-99m MIBI and thallium-201 chloride myocardial scintigraphy in infants.

Myocardial perfusion scintigraphy was performed with both 201Tl and a new six coordinate monocationic isonitrile complex of 99mTc, [99mTc]2-methoxyisobutylisonitrile (MIBI), on 11 infants who had undergone the arterial switch procedure for transposition of the great arteries. Unlike 201Tl which can show rapid and variable rates of washout from myocardium, 73% of the initial first-pass activity of the isonitrile complex in the myocardium remains 1 hr after intravenous administration. The images obtained with [99mTc]MIBI required a shorter recording time, entailed less radiation exposure to the patient, and were qualitatively at least as good as those obtained with 201Tl. No infant had perfusion abnormalities. The potential applications of the isonitrile complexes for myocardial perfusion scintigraphy in children are discussed.

Lung biopsy with frozen section as a diagnostic aid in patients with congenital heart defects.

In eight patients with congenital heart defects and equivocal preoperative hemodynamic data, lung biopsy with frozen section was performed and quantitative morphometric analysis carried out to help select a palliative or corrective surgical procedure. During catheterization it had been possible in only six of the eight patients to enter the pulmonary artery and obtain pressure measurements; four patients had moderate to severe elevation of pulmonary vascular resistance whereas the other two had only mild elevation of pulmonary arterial pressure, but they were being considered for a Fontan procedure. The lung biopsy tissue was taken inflated and fixed inflated in hot glutaraldehyde. From cryostat sections arterial concentration was assessed relative to alveolar concentration, and the degree of arterial muscularity was assessed by wall thickness and extension of muscle; the more advanced Health-Edwards arterial changes were also evaluated. On the basis of the morphologic assessment, six of the eight patients underwent corrective surgery and two underwent a palliative procedure. Postoperative hemodynamic data available in four of the patients who underwent corrective surgery revealed either a significant reduction in pulmonary vascular resistance or return to a normal level of pulmonary arterial pressure, whereas no change has occurred in the one patient studied who underwent a palliative procedure. Assessment of pulmonary arterial development and structure on lung biopsy with frozen section proved helpful in deciding between a palliative and corrective surgical procedure.

Obstructed pulmonary venous drainage with total anomalous pulmonary venous connection to the coronary sinus.

Obstructed pulmonary venous drainage is generally considered extremely rare with total anomalous pulmonary venous connection (TAPVC) to the coronary sinus (CS). A retrospective review of 27 operated patients with TAPVC to CS revealed 6 cases of obstruction (22%). Two of 6 patients who died early had evidence of obstruction at the pulmonary vein confluence at autopsy. Among the 21 hospital survivors, obstruction proximal to the point of CS unroofing developed in 4 (19%), necessitating reoperation and resulting in death in 3. One other patient died late. Mean follow-up of the 17 long-term survivors, who are generally doing well, is 85 months (range 2 to 212). There have been no cases of late obstruction at the site of unroofing among 10 patients who underwent the fenestration procedure suggested by Van Praagh. The incidence of early bradyarrhythmias (60%) does not appear to be decreased by this procedure. Review of 13 autopsy specimens suggests that if the right and left pulmonary veins did not drain directly to the CS but converged to form a short common vertical vein (4 cases), obstruction was likely. When pulmonary artery pressure approaches systemic levels preoperatively, careful echocardiographic and intraoperative assessment of the junction of the pulmonary vein confluence with the CS should be made. If there is evidence of obstruction, consideration should be given to anastomosing the horizontal right and left pulmonary veins directly to the left atrium rather than performing a simple unroofing procedure.

Assessment of hemodynamic status in the intensive care unit immediately after closure of ventricular septal defect.

Hemodynamic values measured 12 to 24 hours postoperatively in the intensive care unit (ICU) were compared with those measured at a later cardiac catheterization in 68 patients after closure of ventricular septal defect (VSD). A pulmonary arterial (PA) saturation of more than 80% or a pulmonary to systemic blood flow ratio (Qp:Qs) greater than 1.5 in the ICU were sensitive indicators for identifying patients at risk of having a hemodynamically significant residual left-to-right shunt (Qp:Qs greater than 1.5) at catheterization. Measurement of PA pressure in the ICU was a useful predictor of PA pressure at catheterization. In the absence of factors known to alter PA pressure, measurement of PA pressure in the ICU overestimates what it will be at a subsequent cardiac catheterization. Early assessment of hemodynamics after closure of VSD is useful in identifying patients at risk of having hemodynamically significant residual VSD and those who may have persistent PA hypertension.

Reoperation for isthmic coarctation of the aorta: follow-up of 26 patients.

Twenty-six patients underwent reoperation for coarctation of the aorta (C of A) between 1972 and 1980. Most patients (73%) had undergone primary repair in infancy. The interval to reoperation was 5 months to 18 years (mean 8.2 years). Indications for reoperation included symptoms in 4, exercise systemic hypertension in 1, electrocardiographic changes of left ventricular strain in 1, arm hypertension in 21, and a C of A gradient at rest greater than 30 mm Hg in all. Surgical procedures included patch aortoplasty (16 patients), bypass graft (6 patients), left subclavian angioplasty (3 patients), and end-to-end anastomosis (1 patient). There were no operative complications or mortality. There was 1 late death from aortic valve disease. Duration of follow-up in the remaining 25 patients was 2 weeks to 7 years (mean 2.5 years). All patients are asymptomatic. C of A gradients were significantly reduced from 30 to 132 mm Hg (mean 56) preoperatively to 0 to 48 mm Hg (mean 15) postoperatively. Right arm systolic blood pressure also was significantly improved from 120 to 237 mm Hg (mean 153) preoperatively to 100 to 160 mm Hg (mean 124) postoperatively. Systemic systolic hypertension persisted in 5 of 25 (20%). It is concluded that C of A reoperation is a low risk procedure that improves symptoms and reduces C of A gradient and arm blood pressure. However, systolic hypertension does not always resolve postoperatively. Patch aortoplasty appears to be a safe and effective surgical approach.

Early assessment of hemodynamic status after repair of tetralogy of Fallot: a comparison of 24 hour (intensive care unit) and 1 year postoperative data in 98 patients.

Hemodynamic data obtained in the intensive care unit, immediately after repair of tetralogy of Fallot, were compared with measurements obtained at 1 year postoperative catheterization in 98 infants and children. Eight of 12 patients who had pulmonary artery oxygen saturation of 80% or greater in the intensive care unit had a pulmonary to systemic flow ratio greater than 1.5 at catheterization; all 79 patients who had a pulmonary artery oxygen saturation of ess than 80% in the intensive care unit had a pulmonary to systemic flow ratio of 1.5 or less at catheterization. Five of six patients who had a right ventricular outflow tract pressure gradient greater than 40 mm Hg in the intensive care unit had a gradient greater than 40 mm Hg at catheterization; 7 of 61 patients who had a right ventricular outflow tract gradient of 40 mm Hg or less in the intensive care unit had a gradient greater than 40 mm Hg at catheterization. The addition of measurements of right ventricular pressure and the right ventricular to systemic arterial pressure ratio in the intensive care unit did not improve sensitivity in identifying patients with a right ventricular outflow tract gradient greater than 40 mm Hg at catheterization. Intensive care unit measurement of pulmonary artery oxygen saturation is valuable for determining the presence or absence of a significant left to right shunt after repair of tetralogy of Fallot and should be considered an adjunct to patient management. Intensive care unit measurement of the right ventricular outflow tract gradient identifies patients with a significant right ventricular outflow tract gradient at catheterization but is not highly sensitive.