Early results of the fontan procedure in one hundred consecutive patients with hypoplastic left heart syndrome.

OBJECTIVES: The purpose of this study was to review a large, single institutional experience with the Fontan procedure for patients with hypoplastic left heart syndrome. METHODS: One hundred consecutive patients with "classic" hypoplastic left heart syndrome underwent Fontan palliation between February 1992 and April 1998. Patient demographic, morphologic, and procedural variables were examined and analyzed. In particular, two different surgical techniques were used: technique I (February 1992 to December 1995) employed cardiopulmonary bypass and moderate systemic hypothermia, and technique II (December 1995 to April 1998), profound hypothermia and circulatory arrest. A retrospective review of medical records was performed and variables were examined and analyzed. RESULTS: Hospital survival for the entire cohort was 89% (95% CI 83%-95%). The technique of operation, cardiopulmonary bypass time, and aortic crossclamp time were each strongly associated with survival. Survival for patients treated by technique I was 79% (95% CI 68-91%; n = 48) and for those treated by technique II, 98% (95% CI 94%-100%; n = 52). Cardiopulmonary bypass and crossclamp times were also highly correlated with time to extubation and length of intensive care unit stay. Preoperative pulmonary artery pressure was correlated with survival; preoperative oxygen saturation, right atrial pressure, pulmonary vascular resistance, pulmonary artery size, extent of aortopulmonary artery collaterals, and echocardiographic estimates of ventricular function and tricuspid regurgitation were not correlated with survival. CONCLUSIONS: Our recent experience with Fontan palliation for patients with hypoplastic left heart syndrome suggests that it is attended by low perioperative mortality. The precise operative technique used appears to be an important determinant of outcome, with the duration of cardiopulmonary bypass and crossclamping being particularly significant.

The abnormal contralateral atrioventricular valve in mitral and tricuspid atresia in neonates: An echocardiographic study.

Abnormalities of the mitral valve (MV) or the tricuspid valve (TV) morphology and/or function in patients with functional single ventricle may result in early morbidity and death. The purpose of this study was to determine the incidence of contralateral atrioventricular valve (AVV) pathologies in mitral valve atresia (MA) and tricuspid valve atresia (TA). We retrospectively reviewed the echocardiographic data of 50 neonates with MV and 20 with TA. Appearance of the papillary muscles, chordae tendinae, and valve leaflets was assessed. AVV regurgitation was semiquantitated by color-flow Doppler and the AVV annulus diameter was measured and indexed to body surface area. MV abnormalities were found in 9 of 20 (45%) of patients with TA. The MV was myxomatous in 9 patients, the leaflets were redundant in 5 patients, and prolapsing occurred in 4 patients. Mild regurgitation was found in 2 patients. In 18 of 20 (90%) patients MV annulus size was larger than 95% of predicted normal values. TV abnormalities were found in 12 of 50 (24%) patients with MA. The TV was myxomatous in 4 patients, prolapsing in 2, and redundant in 3, and moderate TV regurgitation was found in 3 patients. In 29 of 50 (58%) patients TV annulus size was larger than 95% of predicted normal values. Contralateral AVV abnormalities in tricuspid and mitral valve atresia are common and should be assessed carefully before surgical procedures.

Pulmonary venous blood flow pattern in patients with univentricular hearts following total cavo-pulmonary connection.

The objective of the study was evaluation of the pulmonary venous blood flow (PVF) pattern and the influence of ventricular function and atrioventricular valve regurgitation on this flow in patients with univentricular hearts post total cavo-pulmonary connection (TCPC). Transthoracic or transoesophageal echocardiographic studies were performed in 24 children with normal hearts (group A) and in 24 patients with univentricular hearts (group B). Ventricular function and atrioventricular valve regurgitation was semiquantitatively assessed. Systolic/diastolic maximal velocities and velocity time integrals (VTI) were measured from PVF tracings. Ejection fraction was measured by radionuclide angiography in 11 patients. Twelve patients underwent heart catheterization and angiography. In group B the PVF showed a biphasic flow velocity curve. The systolic integrals were smaller and the diastolic integrals were larger than in group A (6.4 vs. 13.0 cm, P = 0.0001, and 13.9 vs. 10.0 cm, P = 0.005). The pulmonary venous systolic flow fraction in 13 patients with an open fenestration and/or atrioventricular valve regurgitation grade 2-3 was significantly lower than in those 11 patients without fenestration and none/small regurgitation (0.19 vs. 0.40, P = 0.05). In conclusion, the PVF pattern in children with univentricular hearts pallitated with TCPC is similar to the PVF pattern found in individuals with biventricular hearts showing a biphasic flow velocity curve despite the absence of pulsatile pulmonary artery flow. The PVF in patients with TCPC-palliated univentricular hearts is influenced by atrioventricular valve regurgitation and fenestration flow.

In vitro analysis of regurgitant fraction using Doppler power-weighted sum of velocities.

The power-weighted sum of velocities (PWS) is the sum of each velocity component of the Doppler signal multiplied by its power. The purpose of this study was to determine (1) whether PWS is linearly related to volume flow and (2) whether PWS can predict the regurgitant fraction in an in vitro pulsatile flow system simulating aortic regurgitation. Doppler analysis of aortic flow was performed with an intact valve and two regurgitant valves. For each valve a linear relation between the forward flow PWS and forward flow volume was demonstrated, with excellent correlation (r = 0.99). For the valves with regurgitant orifices, the values for the PWS-derived regurgitant fraction were compared with measured regurgitant fraction. A fair correlation was demonstrated (r = 0.59), with low accuracy in prediction (error 44% +/- 24%). The PWS was inaccurate in predicting flow ratios in our in vitro system despite the strong relation with forward flow volume. The error incurred may be due to effects of filters that remove low velocity and low amplitude information.

Pulmonary artery size and flow disturbances after patent ductus arteriosus coil occlusion.

Transcatheter closure of patent ductus arteriosus with Gianturco coils may impinge on adjacent vascular structures. The left pulmonary artery relative size may decrease after patent ductus arteriosus coil occlusion; thus, serial follow-up echocardiography is recommended to assess long-term left pulmonary artery growth.

Comparison of simultaneous Doppler- and catheter-derived right ventricular dP/dt in hypoplastic left heart syndrome.

Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function.

Evaluation of left ventricular mass in children with left-sided congenital diaphragmatic hernia.

To evaluate left ventricular (LV) mass in children with left-sided congenital diaphragmatic hernia (CDH), we retrospectively examined the echocardiographic data available on all newborn infants with a diagnosis of CDH between April 1989 and May 1993. Adequate data for evaluation were available for 20 of 31 patients with left-sided CDH and no significant congenital heart disease. Left ventricular mass was determined from two-dimensional echocardiograms by an area-length method. Findings were compared with a control group that consisted of neonates with other causes of pulmonary hypertension. Patients with left-sided CDH had a significantly lower indexed LV mass than control subjects (1.96 gm/kg +/- 0.59 vs 2.84 gm/kg +/- 0.41; p = 0.0001). Additionally, children with left-sided CDH who required extracorporeal membrane oxygenation before repair (n = 7) had a significantly lower indexed LV mass than those patients who did not require extracorporeal membrane oxygenation before repair (1.53 gm/kg +/- 0.50 vs 2.20 gm/kg +/- 0.52; (p = 0.007). Infants who survived (n = 13) had an indexed LV mass of 2.09 gm/kg +/- 0.58 vs 1.64 gm/kg +/- 0.58 in those who died (p = 0.07). We conclude that the LV mass index in children with left-sided CDH is significantly lower than in children with other causes of pulmonary hypertension in the newborn period. Evaluation of LV mass in neonates with left-sided CDH may help predict the need for extracorporeal support before surgical repair, and may help indicate overall prognosis.

Doppler evaluation of femoral arteries in children after aortic balloon valvuloplasty or coarctation balloon angioplasty.

To assess long-term femoral artery complications after aortic balloon valvuloplasty or coarctation balloon angioplasty, we examined 19 children who were 3 weeks to 21 years old (mean 7.6 years) at the time of catheterization. Two-dimensional and Doppler echocardiographic examinations of the common, superficial, and deep femoral arteries were performed at an average of 2.0 years after balloon dilatation. Pulsatility index (PI) was calculated as the maximum velocity minus the minimum velocity divided by the mean velocity. No patient was suspected clinically of having peripheral arterial disease prior to the echocardiographic examination. Fourteen patients had normal femoral arteries. Of these, 10 had normal two-dimensional and Doppler echocardiographic examinations of both femoral arteries. These patients had triphasic flow patterns (forward in systole, reverse in early diastole, forward in middiastole) and Pls of 3.7-41.6 (mean 9.5). Four of the 14 normal patients had abnormal pulsed Doppler examinations showing continuous forward flow and low Pls (1.7-3.5) reflecting residual coarctation (10-30 mmHg gradients). Five patients had abnormal femoral arteries. Of these, two had no visible obstruction by two-dimensional echocardiography and color-flow imaging but had abnormal pulsed Doppler patterns (continuous forward flow and low Pls of 2.5 and 2.9) only on the side of the balloon catheter insertion. Three of the five abnormal patients had visible obstructions by two-dimensional echocardiography and color-flow imaging and had abnormal pulsed Doppler patterns (continuous forward flow and low Pls from 1.1-3.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic evaluation of atrioventricular orifice anatomy in children with atrioventricular septal defect.

In atrioventricular (AV) septal defect, the common AV valve can have a common orifice or can be divided by bridging leaflet tissue into two separate orifices. To determine the accuracy of a two-dimensional echocardiographic technique devised specifically for evaluation of the number of AV valve orifices, all 69 children undergoing surgical repair of AV septal defect from April 1987 to August 1990 were examined prospectively. The presence of bridging leaflet tissue and the number of AV valve orifices were determined with use of a subcostal imaging plane. From a standard subcostal four-chamber view, the plane of sound was rotated 30 degrees to 45 degrees clockwise until the AV valve was seen en face. The plane of sound was then tilted from a superior to an inferior direction so that cross-sectional views of the AV valve were examined from the inferior margin of the atrial septum to the superior margin of the ventricular septum. Of the 69 patients, 6 (9%) were excluded because the appropriate subcostal images were not obtained (in 3 because of obesity and in 3 as a result of operator failure). The remaining 63 children, ranging in age from 1 day to 13.5 years and in weight from 1 to 55 kg, constituted the study group. Echocardiographic results were compared with surgical observations in 62 patients and with autopsy findings in 1 patient. With the two-dimensional echocardiographic technique, 32 of 33 patients with a common orifice and 28 of 30 patients with two separate AV valve orifices were correctly identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler evaluation of aortic valve area in children with aortic stenosis.

To evaluate the usefulness of the Doppler-derived aortic valve area calculated from the continuity equation in assessing the hemodynamic severity of aortic valve stenosis in infants and children, two-dimensional and Doppler echocardiographic examinations were performed on 42 patients (aged 1 day to 24 years) a median of 1 day before or after cardiac catheterization. The left ventricular outflow tract diameter was measured from the parasternal long-axis view at the base of the aortic cusps from inner edge to inner edge in early systole. The flow velocities proximal to the aortic valve were measured from the apical view with use of pulsed Doppler echocardiography; the jet velocities were recorded from the apical, right parasternal and suprasternal views by using continuous wave Doppler echocardiography. The velocity-time integral, mean velocity and peak velocity were measured by tracing the Doppler waveforms along their outermost margins. Seventeen patients (all less than or equal to 6 years old) had a very small left ventricular outflow tract diameter (less than or equal to 1.4 cm) and cross-sectional area (less than or equal to 1.5 cm2). The Doppler aortic valve area calculated with use of velocity-time integrals in the continuity equation (0.57 +/- 0.25 cm2/m2, mean value +/- SD) correlated well with the Doppler aortic valve area calculated by using mean (0.55 +/- 0.25 cm2/m2) and peak (0.54 +/- 0.24 cm2/m2) velocities, with correlations of r = 0.97 and 0.95, respectively. Thirty-four patients had sufficient catheterization data to calculate aortic valve area from the Gorlin formula.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler assessment of pulmonary artery flow patterns and ventricular function after the Fontan operation.

To assess the relation between ventricular systolic and diastolic function and pulmonary artery (PA) flow patterns after the Fontan operation, 15 postoperative patients were prospectively evaluated with echocardiography. Blood flow velocities in the PA were recorded with pulsed Doppler echocardiography. Ejection fraction was measured by 2-dimensional echocardiography using Simpson's rule. Indexes of diastolic function were measured from the systemic atrioventricular valve inflow Doppler and included peak E and A velocities, peak filling rate normalized for stroke volume, the fractions of filling in early and late diastole (E and A area fractions), and the E/A velocity and area ratios. Compared with 15 age-matched control subjects, the 15 patients who had undergone the Fontan procedure had decreased peak E velocity (0.65 +/- 0.20 vs 0.87 +/- 0.10 m/s), decreased E/A velocity ratio (1.29 +/- 0.23 vs 1.98 +/- 0.46), decreased normalized peak filling rate (6.09 +/- 0.90 vs 6.81 +/- 0.83 s-1), decreased E area fraction (0.63 +/- 0.09 vs 0.72 +/- 0.07), increased A area fraction (0.37 +/- 0.07 vs 0.24 +/- 0.06), and decreased E/A area ratio (1.77 +/- 0.45 vs 3.33 +/- 1.15) (p less than 0.05). These diastolic filling abnormalities are consistent with impaired ventricular relaxation and decreased early diastolic transvalvular pressure gradient. PA Doppler recordings showed 2 distinct patterns of flow. Pattern I, observed in 9 patients, showed biphasic forward flow with peak velocities in mid to late systole and mid-diastole. Pattern II, observed in the remaining 6 patients, showed decreased systolic forward flow, a late systolic to early diastolic flow reversal, and delayed onset of diastolic forward flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular ejection fraction measured with Doppler color flow mapping techniques.

To determine if left ventricular (LV) ejection fraction (EF) can be accurately measured from the color Doppler examination, 11 patients (aged 0.4 to 22 years) underwent 2-dimensional and color Doppler examinations within 24 hours of cardiac catheterization. With use of a biplane Simpson's rule, LV end-diastolic volume, end-systolic volume and EF were measured from cineangiograms, 2-dimensional echocardiograms and color Doppler examinations. The 2-dimensional echocardiographic and color Doppler measurements were obtained from apical 4-chamber and long-axis views. The color Doppler examinations were performed by placing the color sector over the left ventricle only. The velocity scale was set at the lowest possible Nyquist limit (less than 0.17 m/s), and the highest possible carrier frequency was used to obtain this limit. With these settings, all flow signals in the LV chamber were aliased so that the entire chamber was filled with mosaic color Doppler signals. Motion of the surrounding LV walls gave rise to nonaliased (pure red-blue) signals. With use of an off-line analysis system equipped with a color frame grabber, the border of the mosaic color flow area was traced to obtain volumes and EF. End-diastolic and end-systolic volumes measured with color Doppler correlated well with those measured from 2-dimensional echocardiography (r = 0.99, standard error of the estimate [SEE] = 11.9 ml; r = 0.99, SEE = 4.4 ml, respectively) and cineangiography (r = 0.92, SEE = 16.8 ml; r = 0.90, SEE = 9.9 ml, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term assessment of right ventricular diastolic filling in patients with pulmonic valve stenosis successfully treated in childhood.

Patients with severe pulmonic stenosis (PS) have right ventricular (RV) diastolic filling abnormalities detectable by tricuspid valve pulsed Doppler examination. To determine if these abnormalities persist long term after successful therapy of PS, 19 patients were examined 8 +/- 3 years after PS therapy. At the time of follow-up Doppler examination, the PS gradient was 15 +/- 8 mm Hg. From the tricuspid valve inflow Doppler study, the following measurements were obtained at peak inspiration: peak velocities at rapid filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, RV peak filling rate normalized for stroke volume, deceleration time, the fraction of filling in the first 0.33 of diastole as well as under the E and A waves, and the ratio of E to A area. Data from PS follow-up patients were compared with our previously reported data from 12 age-related control subjects and 14 untreated patients with PS. Patients with PS who were followed up had higher peak E velocity (0.75 +/- 0.14 vs 0.59 +/- 0.21 m/s), lower peak A velocity (0.47 +/- 0.09 vs 0.64 +/- 0.28 m/s), higher E/A velocity ratio (1.65 +/- 0.33 vs 1.11 +/- 0.52), higher 0.33 area fraction (0.52 +/- 0.08 vs 0.34 +/- 0.14), lower A area fraction (0.29 +/- 0.06 vs 0.45 +/- 0.21) and higher E/A area ratio (2.48 +/- 0.82 vs 1.73 +/- 1.05) than PS patients without treatment (p less than 0.03). All Doppler indexes of the patients with PS who were followed up were the same as those of the control subjects except for the peak E velocity that was slightly higher (0.75 +/- 0.14 vs 0.63 +/- 0.11 m/s), the peak A velocity that was slightly higher (0.47 +/- 0.09 vs 0.38 +/- 0.09 m/s) and the E/A area ratio that was slightly lower (2.48 +/- 0.82 vs 3.50 +/- 1.25) (p less than 0.03). Thus, at long-term follow-up, all RV diastolic filling indexes in successfully treated patients with PS improved compared with the untreated patients and approached values found in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulsed Doppler evaluation of right ventricular diastolic filling in children with pulmonary valve stenosis before and after balloon valvuloplasty.

To assess right ventricular (RV) diastolic filling in children with pulmonary stenosis (PS), 14 patients (mean age 5.1 years) were examined immediately before and after pulmonary balloon valvuloplasty. Fourteen normal children (mean age 4.8 years) were also studied. From the tricuspid valve inflow Doppler study, the following measurements were made at peak inspiration: peak velocities at rapid filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, RV peak filling rate normalized for stroke volume, total area under the Doppler curve, percent of the total Doppler area occurring in the first third of diastole (0.33 area fraction), percent of the total area occurring under the E wave (E area fraction), percent of the total area occurring under the A wave (A area fraction) and the ratio of E area to A area. Before balloon valvuloplasty, the patients with PS had higher peak A velocity (0.64 +/- 0.28 vs 0.39 +/- 0.08 m/s), lower E/A velocity ratio (1.11 +/- 0.52 vs 1.76 +/- 0.45), lower 0.33 area fraction (0.34 +/- 0.14 vs 0.49 +/- 0.08), higher A area fraction (0.45 +/- 0.21 vs 0.27 +/- 0.09) and lower E/A area ratio (1.73 +/- 1.05 vs 2.96 +/- 1.14) than the normal subjects (p less than 0.01). In patients before and after balloon valvuloplasty, there was a significant difference in RV outflow gradient (71 +/- 35 vs 28 +/- 15 mm Hg), but there was no change in any Doppler index. Thus, patients with PS have abnormal diastolic filling with decreased filling in early diastole and increased filling during atrial contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-dimensional echocardiographic and color flow Doppler detection of an unusual pulmonary venous anomaly: anomalous right pulmonary venous return to the right atrium by way of three separate orifices.

In this report, we describe the echocardiographic findings of a patient with anomalous right pulmonary venous return to the right atrium by way of three separate pulmonary vein orifices. The color flow Doppler examination was essential for identification of the pulmonary veins and their connection to the right atrium.