Simultaneous real-time imaging of four-chamber and left ventricular outflow tract views using xPlane imaging capability of a matrix array probe.

OBJECTIVES: To determine the feasibility and reliability of using xPlane imaging to examine simultaneously the four-chamber and left ventricular outflow tract (LVOT) views in real time, to assess rotation angles from the four-chamber view to the LVOT view, and to investigate factors affecting the angles. METHODS: In 145 fetuses at 11-37 weeks' gestation, we visualized the four-chamber view in one of three cardiac positions: a subcostal view with the apex at the 3 or 9 o'clock position; an apical view with the apex at the 12 or 6 o'clock position; or a view with the fetal heart apex midway between these two positions. We then used the rotation function of xPlane imaging, using the four-chamber view as the reference plane, to visualize the LVOT view simultaneously in real time on the secondary image plane, on the right side of the split screen, by rotating a reference line from 0° with a rotation step of 5°. The rotation angle necessary for the first appearance of LVOT was recorded as the first rotation angle. The reference line was then rotated until the LVOT was just out of view, and this last rotation angle was recorded as the second rotation angle. The difference between these two angles was recorded as the angle span of the LVOT display. Reliability was assessed by intraclass correlation coefficient (ICC). RESULTS: Of the 145 fetuses examined, 29 had cardiac defects. Using xPlane imaging, the LVOT was visualized successfully after 14 weeks in 95.1% of cases. The first and second rotation angles varied significantly with cardiac position (P < 0.001); when the fetal heart was examined using a subcostal approach with the apex at the 3 or 9 o'clock position, the first rotation angle was smaller than that at the apical view for normal hearts (20° vs. 50°, P < 0.001). There was also a significant difference for the second rotation angle and for the angle span, between fetuses with and without normal LVOT (P = 0.038 and 0.006, respectively). Regarding intra- and interobserver reliability for measurement of first and second rotation angles, the ICCs were high (range, 0.847-0.980). CONCLUSION: Using xPlane imaging, it is feasible to examine simultaneously the four-chamber and LVOT views in real time, and measurement of the rotation angles between these two views is reproducible. The rotation angles depend on the position of the fetal heart, and the normality of the LVOT. Proposed algorithms for examination of the fetal heart with three-/four-dimensional ultrasonography may need to be adapted to optimize visualization of the standard planes.

Evolution of the management approach for pulmonary atresia with intact ventricular septum.

OBJECTIVE: To review the evolution of the management approach for pulmonary atresia with intact ventricular septum (PAIVS) in the past two decades and to assess its impact on patient outcomes. DESIGN AND PATIENTS: Retrospective review of the management and outcomes of 94 patients (55 male patients) with PAIVS diagnosed between July 1980 and August 2003. SETTINGS: Tertiary paediatric cardiac centre. RESULTS: Seven patients died before interventions. Of the remaining 87 patients who underwent intervention at a median age of 9 days (from 1 day to 2 years), 12 had right ventricular outflow tract reconstruction (RVOTR), 42 had closed pulmonary valvotomy (CPV), and 15 had laser assisted valvotomy with balloon valvoplasty. A systemic-pulmonary shunt was inserted in 18 patients, six of whom had subsequent RVOTR (n = 4) or laser assisted valvotomy (n = 2). Since 1990, catheter intervention accounted for 38% (17 of 45) of the right ventricular outflow procedures. The mean (SEM) freedom from reintervention was 93 (7)%, 71 (12)%, and 57 (13)% after RVOTR, 75 (7)%, 40 (8)%, and 14 (6)% after CPV, and 54 (13)%, 24 (12)%, and 16 (10)% after laser assisted valvotomy at one month, six months, and one year, respectively (RVOTR versus CPV, p < 0.001; RVOTR versus laser assisted valvotomy, p = 0.001). Low cardiac output syndrome was significantly less common after catheter intervention than after RVOTR (0% v 44%, p = 0.003) or CPV (0% v 29%, p = 0.01). The overall mean (SEM) survival was 77 (5)% and 70 (5)% at one and five years, respectively, and the overall mortality was 33% (29 of 87). There were no significant differences in survival between the three groups. CONCLUSIONS: Multiple interventions are often required in the treatment algorithm of PAIVS. The shift towards increased use of the transcatheter approach has reduced the occurrence of postprocedural low cardiac output syndrome.

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

OBJECTIVES: To use dobutamine stress echocardiography to determine left ventricular (LV) function and wall motion of children long term after arterial switch operation (ASO) for transposition of the great arteries. DESIGN AND PATIENTS: 31 patients (24 boys) with ASO performed at a mean (SD) of 15.5 (4.3) days of life were studied at an age of 9.4 (2.0) years. All had normal coronary angiographic findings. LV echocardiographic indexes, including fractional shortening, ejection fraction, rate corrected velocity of circumferential fibre shortening (VCFc), and wall stress, as well as LV wall motion abnormalities were determined at rest and under dobutamine stress. The results were compared with those of 20 healthy age matched control participants. SETTING: Tertiary paediatric cardiac centre. RESULTS: Fractional shortening, ejection fraction, and VCFc were significantly lower in patients than in controls at rest (all with p < 0.001). Stress-velocity index detected impaired LV contractility in 19 (61%) patients at rest. An older age at operation (p = 0.01), longer bypass (p = 0.01) and circulatory arrest times (p = 0.045), and an unusual coronary artery pattern (p = 0.059) were associated with impaired resting LV contractility. Dobutamine stress echocardiography unmasked wall motion abnormalities in 23 (74%) patients. Exercise myocardial perfusion scan, performed in 22 patients, showed reversible myocardial perfusion defects in 17. These defects corresponded to segments of hypokinesia as detected by dobutamine stress echocardiography. CONCLUSION: A significant proportion of children, albeit asymptomatic, had impaired baseline LV contractility and reversible myocardial perfusion defects and mild wall motion abnormalities on stress after ASO.

Parents' understanding of their child's congenital heart disease.

OBJECTIVES: To assess parents' understanding of their child's congenital heart disease in various knowledge domains and to identify significant determinants of parental knowledge. DESIGN: Cross sectional questionnaire survey SETTING: Tertiary paediatric cardiac centre. PATIENTS: 156 parents of children with relatively simple congenital heart defects were recruited from the outpatient clinic of a tertiary cardiac centre over a three month period. The questionnaire comprised 10 items of knowledge under three domains: nature of heart disease and its treatment; impact of heart disease on exercise capacity; and infective endocarditis and its prevention. The frequency distribution of the parents' knowledge in the different domains was determined. Univariate analyses and logistic regression were performed to identify significant determinants of knowledge in selected items. RESULTS: While 59% of parents correctly named their child's congenital heart disease, only 28.8% correctly indicated the heart lesion(s) diagrammatically. However, more than 80% of parents were aware of the indications and aims of previous surgical and transcatheter interventions. About half of the parents were aware of possible aetiologies and of the hereditary nature and symptoms attributable to underlying heart disease. Disappointingly, of the 56 parents whose children were taking cardiac medications, only 25 (44.6%) and 4 (7.1%) knew correctly the functions and important side effects of the medications, respectively. With regard to exercise capacity, 59% of parents indicated its level appropriate for the heart lesion. While 26.9% of parents had heard of the term "infective endocarditis", slightly more than half of the parents were aware of the need for antibiotics before dental procedures. Significant determinants of knowledge in the nature of heart disease were cardiac diagnosis, occupation of parents, and their educational level. Logistic regression failed to identify any significant determinants of parental knowledge in the other two domains. CONCLUSIONS: Parents of children with congenital heart disease have important knowledge gaps. Our findings suggest that the current educational programme is inadequate and needs to be refined to promote better parental understanding of their child's heart disease, with the ultimate aim of enabling parents to impart such knowledge accurately to their children.

Pericardial effusion after open heart surgery for congenital heart disease.

OBJECTIVES: To determine the prevalence and time course of pericardial effusion after open heart surgery for congenital heart diseases and to identify predisposing risk factors. DESIGN AND PATIENTS: Prospective assessment of development of pericardial effusion in 336 patients (163 males) undergoing open heart surgery for congenital heart disease by serial echocardiography on days 5, 7, 14, 21, and 28 postoperatively. SETTING: Tertiary paediatric cardiac centre. RESULTS: The prevalence of pericardial effusion was 23% (77 of 336). Of the 77 patients who developed effusion, 43 (56%) had moderate to large effusions and 18 (23%) were symptomatic. Patients who had a large amount of effusion were more likely to be symptomatic than those with only a small to moderate amount (47.4% v 15.5%, p = 0.01). The mean (SD) onset of pericardial effusion was 11 (7) days after surgery, with 97% (75 of 77) of cases being diagnosed on or before day 28 after surgery. The prevalence of effusion after Fontan-type procedures (60%, 6 of 10) was significantly higher than that after other types of cardiac surgery: repair of left to right shunts (22.1%, 43 of 195), repair of lesions with right ventricular outflow tract obstruction (22.6%, 19 of 84), arterial switch operation (6.7%, 1 of 15), and miscellaneous procedures (25%, 8 of 32) (p = 0.037). Univariate analyses showed that female patients (p = 0.009) and those receiving warfarin (p = 0.002) had increased risk of postoperative pericardial effusion. A greater pericardial drain output in the first four hours after surgery also tended to be significant (p = 0.056). Multivariate logistic regression similarly identified warfarin treatment (beta = 1.73, p = 0.009) and female sex (beta for male = -0.63, p = 0.037) as significant determinants. CONCLUSIONS: Pericardial effusion occurs commonly after open heart surgery for congenital heart disease. Serial echocardiographic monitoring up to 28 days postoperatively is indicated in selected high risk patients such as those with symptoms of postpericardiotomy syndrome and those given warfarin.

Tracheobronchography and angiocardiography of paediatric cardiac patients with airway disorders.

OBJECTIVE: We report our experience in combining tracheobronchography and angiocardiography in the assessment of a selected cohort of paediatric cardiac patients with problematic airway disorders. METHODOLOGY: The clinical records of 11 patients who underwent 17 studies at a median age of 5.5 months (range 3 months to 10.8 years) were reviewed. Tracheobronchography and angiocardiography were performed under general anaesthesia using a non-ionic contrast agent. The findings were compared with those of flexible bronchoscopy and magnetic resonance imaging (MRI). RESULTS: Seven patients had cardiac lesions associated with vascular anomalies potentially compressing the airway, while four had no identifiable aberrant or enlarged vessels. All examinations but one were performed without complications. Tracheobronchography demonstrated extrinsic vascular compression with secondary airway malacia in three (27%), intrinsic tracheobronchial stenosis in five (45%), and airway malacia in three patients (27%). Precise measurement of the airway calibre and real-time fluoroscopic monitoring facilitated transcatheter tracheobronchial interventions (six balloon dilations, three stent implantations) in four patients. In conjunction with angiocardiography, cine-tracheobronchography provided detailed information on the spatial relationship between vascular and airway structures in all patients; allowed dynamic assessment of airway malacia; and facilitated preoperative planning in six patients. In contrast, bronchoscopy failed to differentiate malacia from extrinsic compression in four patients (36%), while MRI, performed in six patients, was unsatisfactory in one due to a motion artefact and failed to diagnose airway malacia and extrinsic compression in three patients. CONCLUSIONS: Tracheobronchography is relatively safe in paediatric cardiac patients. Combined tracheobronchography and angiocardiography, a less operator-dependent imaging modality compared to bronchoscopy and MRI, delineated the airway and vascular anatomy in detail; facilitated preoperative planning; and permitted transcatheter tracheo-bronchial interventions. The dynamic capability of tracheobronchography supplements that of flexible bronchoscopy and MRI in the diagnosis of airway malacia.

Outcome of infants with right atrial isomerism: is prognosis better with normal pulmonary venous drainage?

OBJECTIVE: To compare the outcome of infants and children who have right atrial isomerism and normal pulmonary venous drainage with those who have anomalous drainage, and to determine factors associated with poor outcome. DESIGN AND PATIENTS: Retrospective review of management and outcome of 116 infants and children determined to have right atrial isomerism between January 1980 and December 2000. SETTING: Tertiary paediatric cardiac centre. RESULTS: The 116 patients presented at a median of one day (range 1 day to 3.7 years) with cyanosis in the majority (96%). No interventions were planned in 31 (27%) patients, all of whom died. The early surgical mortality for pulmonary venous repair was 25% (2 of 8), Fontan procedure 26% (5 of 19), cavopulmonary shunting 7.7% (1 of 13), and systemic pulmonary arterial shunt insertion 1.9% (1 of 53). Late mortality was related to infection (n = 10), sudden death of unknown aetiology (n = 7, 5 with history of arrhythmia), and documented arrhythmia (n = 1). Patients with obstructed anomalous pulmonary venous drainage had the worst survival (p < 0.001). The mean (SEM) survival estimates for those with normal pulmonary venous drainage at 1, 5, 10, and 15 years was 81 (5.3)%, 67 (6.6)%, 60 (7.8)%, and 43 (12)%, respectively, similar to those for patients with non-obstructed anomalous drainage (p = 0.06). Independent risk factors for mortality included pulmonary venous obstruction (relative risk 3.8, p = 0.001) and a single ventricle (relative risk 2.9, p = 0.016). An analysis of only patients with normal pulmonary venous drainage identified no risk factors for mortality. CONCLUSIONS: The long term outcome of infants and children with right atrial isomerism in association with a normal pulmonary venous drainage remains unfavourable. Sepsis and sudden death that may potentially be related to cardiac arrhythmia are major causes of late mortality.

Analysis of indications for surgical closure of subarterial ventricular septal defect without associated aortic cusp prolapse and aortic regurgitation.

Subarterial ventricular septal defect (VSD) is relatively common in Orientals. We reviewed the outcome of 214 patients (137 males) who were followed for 8.6 +/- 5.2 years (range 0.1 to 24.3) and addressed the issue regarding the necessity and optimum timing of closing subarterial defects before development of aortic valve deformities. Demographic data, transthoracic and transesophageal echocardiographic findings, cardiac catheterization results, and operative findings were reviewed. Kaplan-Meier actuarial analysis was performed to assess the development of aortic valve complications over time. Seventy-five patients with heart failure and pulmonary hypertension underwent surgical closure of VSD at the age of 2.4 +/- 2.9 years. No patient had aortic cusp prolapse before operation and none developed aortic cusp prolapse or aortic regurgitation (AR) on follow-up. In contrast, of the 139 asymptomatic patients managed conservatively, 102 (73%) developed aortic cusp prolapse, 78% of whom (80 of 102) developed AR. The prevalence of aortic cusp prolapse and AR at 1, 5, 10, and 15 years old was 8%, 30%, 64%, and 83%, and 3%, 24%, 45%, and 64%, respectively. Significant prolapse or AR prompted surgical closure of VSD with (n = 22) or without (n = 26) valvoplasty in 48 of 102 patients (47%). The size of the VSD was significantly larger in patients with heart failure (9.6 +/- 3.3 mm) or aortic cusp prolapse (11.7 +/- 4.1 mm) compared with those without heart failure (4.5 +/- 1.4 mm, p <0.001). All patients with aortic cusp prolapse and all but 1 with heart failure had a defect size of > or =5 mm. In conclusion, subarterial VSD of > or =5 mm should be closed as early as possible to prevent development of aortic cusp prolapse and AR. Asymptomatic patients with small defects <5 mm could be managed conservatively.

Evolving management for critical pulmonary stenosis in neonates and young infants.

Over the years, management of critical pulmonary stenosis in young infants has evolved from surgical reconstruction of the right ventricular outflow tract and closed pulmonary valvotomy to transcatheter balloon valvoplasty. Our study aimed at evaluating how the changing policy for management had affected the immediate and long term outcomes of babies with this cardiac lesion. Interventions were made in 34 infants at a median age of 8.5 days (2-90 days). Reconstruction of the right ventricular outflow tract reconstruction was performed in 10 patients, closed pulmonary valvotomy in 13, and balloon valvoplasty in 11. Initial procedure-related mortality was 50%, 15% and 0% respectively. Multivariate analysis revealed transannular patching of the right ventricular outflow tract, and male sex, to be significant factors for death. For the 27 survivors, the ratio of right ventricular to systemic systolic pressure decreased from 1.6 +/- 0.3 to 0.3 +/- 0.2 after reconstruction of the outflow tract, 1.8 +/- 0.5 to 0.8 +/- 0.4 after closed valvotomy, and 1.8 +/- 0.6 to 0.9 +/- 0.3 after balloon valvoplasty. The decrease was significantly greater after patch reconstruction (p=0.025) that required no further reinterventions. The overall rate of reintervention for the survivors was 37% (10/27). The freedom from reintervention after closed valvotomy was 82%, 64% and 51% at 1, 5 and 10 years respectively. The figure remained at 78% at both 1 and 5 years (p=0.66) after balloon valvoplasty. The higher reintervention rate for closed valvotomy corresponded to the significantly greater residual gradient across the pulmonary valve noted on follow-up (p=0.01). Reinterventions included balloon dilation (n=6), reconstruction of the outflow tract (n=4), and 1 each of ligation of an arterial duct and systemic-pulmonary arterial shunting. The risk factor for reintervention was a hypoplastic right ventricle. In conclusion, transcatheter balloon valvoplasty appears to be the optimum initial approach in view of its low mortality, efficacy at relieving the obstruction, and low rate of reintervention.

Surgical validation and implications for transcatheter closure of quantitative echocardiographic evaluation of atrial septal defect.

Accurate evaluation of secundum atrial septal defect (ASD) is important for the success of transcatheter closure. The purpose of this study was (1) to describe a quantitative evaluation by transthoracic (TTE) and transesophageal (TEE) echocardiography of the various morphologic features of ASD that might be important for patient selection for transcatheter closure, and (2) to assess the reliability of these 2 methods by surgical findings. Preoperative TTE and TEE were used to evaluate the ASD of 27 children undergoing surgical closure. Measurements included the diameters of ASD and the atrial septal lengths in the transverse and longitudinal axis, and the width of the superior, inferior, anteroinferior, and posterior septal margins. The shape and location of the ASD and the adequacy of the septal margins for anchoring occluding devices were determined. Echocardiographic data were compared with corresponding surgical measurements. No significant difference occurred in the means of all the parameters measured with the 3 methods, except for the transverse ASD diameter (p <0.05). Good agreement occurred between TTE and TEE and surgical data, except for the transverse ASD diameter, transverse atrial septal length, and the posterior septal margin on TTE. Intraclass correlations between TTE and TEE and surgical measurements of all parameters were good, except for the transverse ASD diameter. The accuracy in determining shape and location of the ASD by TTE and TEE were 100%, whereas that for determining the adequacy of septal margins was 98% and 97%, respectively. In conclusion, TTE and TEE are reliable methods for quantitative evaluation of ASD.

Early and intermediate-term complications of self-expanding stents limit its potential application in children with congenital heart disease.

OBJECTIVES: We report on the early and intermediate-term follow-up results of self-expanding Wallstent (Schneider, Switzerland) implanted in children with congenital heart disease. BACKGROUND: The inherent shortcomings of balloon-expandable stents prompted the trial of an alternative stent. METHODS: Twenty patients underwent 22 implantations of 25 self-expanding Wallstents between December 1993 and June 1997 in two institutions. The mean age and weight were 10.8+/-4.5 years and 30.5+/-14.2 kg, respectively. The patients were divided into two groups: 1) Group I comprised 17 patients with pulmonary arterial stenoses, 2) Group II comprised four patients with venous stenoses (one belonged to both groups). Sixteen patients underwent recatheterization at a median of 5.8 months (range 0.5 to 31, mean 8.1 months) after stenting. Hemodynamic and angiographic changes after the interventional procedures and complications were documented. RESULTS: All the stents were successfully deployed in the intended position. In Group I, the narrowest diameter of the stented vessel increased from 4.1+/-1.5 to 8+/-2 mm (95% increase, p < 0.0001) while the systolic pressure gradient across decreased from 24.6+/-15.8 to 12.1+/-11.4 mm Hg (51% decrease, p = 0.001). In Group II, the dimensional changes of the narrowest segment increased from 4.3+/-0.5 to 7.5+/-0.4 mm (75% increase, p = 0.003), and the pressure gradient reduced from 5.0+/-2.9 to 0.9+/-1.0 mm Hg (82% decrease, p = 0.04) across the stented venous channel. Distal migration of two optimally positioned stents occurred within 24 h of implantation. At recatheterization, significant neointimal ingrowth (>30% of the expanded diameter) was noted in 7 (28%) of the 25 implanted stents. This responded poorly to balloon dilation. Predisposing factors for the neointimal ingrowth included stents of smaller diameter (<9 mm) and longer period after implantation. CONCLUSIONS: Self-expanding Wallstent could be deployed easily and safely to relieve vascular stenoses in children. The complications of distal migration, significant neointimal ingrowth and its unyielding design to overdilation limit its application to this patient group.

Management of branch pulmonary artery stenosis: balloon angioplasty or endovascular stenting.

1. The surgical outcome of congenital heart diseases may be adversely affected by residual branch pulmonary artery stenosis, which is difficult to treat surgically. 2. The objective of the present study was to evaluate the effectiveness, safety and follow-up results of two transcatheter procedures, balloon angioplasty and endovascular stenting, for treatment of branch pulmonary artery stenosis. 3. From December 1988 to March 1997, 22 children (group 1) underwent 30 balloon angioplasties and 12 children (group 2) underwent 14 endovascular stent implantations. The overall success rates for groups 1 and 2 were 67 (20/30) and 93% (13/14), respectively, with significant increases in vessel diameter (P < 0.001, t-test, 29 d.f.; P = 0.0001, t-test, 12 d.f., respectively) and decreases in pressure gradient (P < 0.0001, t-test, 29 d.f.; P = 0.001; t-test, 12 d.f., respectively). One death (3.3%) in group 1 was due to post-dilation reactive pulmonary hypertension. No mortality occurred in group 2 children, but two migrated stents required re-implantation of another stent. Mean follow-up periods were 28.2 and 26.3 months for groups 1 and 2, respectively. For group 1, no significant change in vessel diameter or pressure gradient was noted on recatheterization in 12 patients. Restenosis occurred in four of 16 (25%) initial successes. Balloon redilation in four vessels were all successful. For group 2 children, although vessel diameter remained unchanged, a significant increase in pressure gradient (P = 0.02; t-test, 11 d.f.) was noted on recatheterization. Balloon dilations on two narrowed stents caused by intimal proliferation showed only partial improvements. 4. In conclusion, both balloon angioplasty and endovascular stent implantation are effective and safe, with satisfactory intermediate-term results, for the treatment of branch pulmonary artery stenosis. Balloon angioplasty is the choice for initial treatment, whereas stent implantation, the long-term outcome of which remains to be determined, should be reserved for older children after repeated failures with balloon dilation.

Initial sensitivity, acute tolerance and alcohol consumption in four inbred strains of rats.

Initial sensitivity and acute tolerance to ethanol were determined in a jumping test in separate groups of spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WKY) rats, and of Dahl salt-sensitive (SS) and salt-resistant (SR) rats. One week later, voluntary consumption of ethanol was studied in all groups. SH rats were found to be more sensitive than WKY, but there was no difference in acute tolerance development between these two strains. SH rats, however, drank significantly more alcohol than the WKY in both the two-bottle choice paradigm and the limited access model. Similarly, SS rats drank significantly more alcohol than the SR rats, although SS rats were found to be more sensitive to ethanol than SR. There was again no difference in acute tolerance development between these two strains. These observations suggest that difference in alcohol consumption in these strains cannot be accounted for by significant differences in acute tolerance or in initial sensitivity to ethanol.