Posterpresentation on December 2010:
NEURALLY ADJUSTED VENTILATORY ASSIST (NAVA) VENTILATION IN INFANTS WITH PARESIS OF N. PHRENICUS AFTER CORRECTION OF CONGENITAL HEART DISEASE
Robert Weinzettel, Paul Braza, Irmgard Pomberger , Franz Hornath , Helene Seipelt, Gertraud Geiselseder, Gerald Tulzer
NAVA.pdf

Early and mid-term results of the arterial switch operation (ASO) in 114 consecutive patients: a single center experience

Prandstetter C, Hofer A, Lechner E, Mair R, Sames- Dolzer E, Tulzer G

Background: The ASO has become the treatment of choice in patients with simple or complex transposition of the great arteries (TGA). The purpose of this study was to assess early and mid-term outcome in a single center after ASO in this patient collective. 

Patients and methods: Between 1995 and December 2005 114 consecutive patients underwent an ASO at our institution, performed by one single surgeon. Patient charts, echo- and angiograms were retrospectively reviewed and patients were analyzed in 3 different groups: Group I consisted of  77 neonates with TGA and intact ventricular septum, group II of 13 patients with TGA and ventricular septal defect which had to be closed surgically and group III of 24 neonates with varies forms of TGA in a complex setting (table2). The median weight was 3.23 kg (range: 1.65 – 8.30) . Twenty five neonates were born preterm, 18 diagnosed prenatally.

 Results: Thirty-day mortality rate of 1.75% was observed after complete of follow up with 1 further late death (0.89%) . Only one early coronary event occurred, no late events have been reported. After a median follow-up of 20.7 months (range 0.3-128.6) of 111 survivors 10 required cardiovascular reoperation, all but 1 came out of group III. Freedom from reoperation at 5 years was: 87.5%. Prevalence of supravalvular pulmonary stenosis was 4.7%. In our patient series the only risk factor for increased mortality and morbidity was a body weight of less than 2500g at the time of operation. No better outcome could be demonstrated in the prenatal diagnosed patients.

 Conclusion: The ASO can be performed safely and with a low mortality and morbidity even in patients with complexe TGA. Follow-up of these patients is required to detect residual problems like supravalvular pulmonary stenosis, coronary problems, arrhythmias and aortic valve dysfunction.

N-terminal-pro-B natriuretic peptide levels correlate with signs of heart failure in patients after Fontan operation

Lechner E, Gitter R, Mair R, Schreier-Lechner E, Vondrys D, Tulzer G
Introduction: Ventricular function is critical in the long-term management of patients with Fontan physiology. Early and minor deteriorations are difficult to assess.
Purpose of the study: to test the hypothesis that plasma levels of N-terminal-pro-B natriuretic peptide (NT-pro BNP) in children after Fontan operation correlate with clinical sings of heart failure (CHF).
Patients and methods: NT-pro BNP plasma levels of 59 children (age: xx years,  range:  years) after Fontan operation (median time of follow up:  years, range   years) were measured using an automated enzyme immuno assay (Roche Diagnostics). All Fontan patients had a complete clinical and echocardiographic examination by a pediatric cardiologist. Clinical signs of CHF was considered if at least two of the following criteria were fulfilled: cardiomegaly in x-ray, more than mild AV – insufficiency or decreased ventricular function at echocardiography and dyspnea, tachypnea, tachycardia, hepatomegaly or failure to thrive at clinical examination. Xx patients had hypoplastic left heart syndrome,  had single ventricle, xx had tricuspid atresia, xx had double outlet right ventricle with transposed great arteries, xx pulmonary atresia with intact ventricular septum, xx double outlet right ventricle and straddling mitral valve.
Results: 14/59 patients after Fontan operation had signs of CHF. In patients with CHF the NT-pro BNP levels were significantly higher (median 248.95, range: 125.2 – 1561 pg/ml) than in patients without CHF (median 94.3, range: 19.5 - 300.5 pg/ml).
Conclusion: Plasma NT-pro BNP levels are a useful tool in detecting CHF in patients postoperative Fontan operation. In the future plasma NT-pro BNP levels may be useful in monitoring the effect of various treatments for CHF in children postoperative Fontan procedure.

Successful biventricular repair following in-utero balloon dilation of critical aortic stenosis
G.Tulzer, W.Arzt, R.Mair, E.Lechner, G.Geiselseder
Children’s Heart Center Linz, Linz, Austria

Critical aortic stenosis (AS) with reversed aortic arch flow in the mid-trimester fetus usually evolves into hypoplastic left heart syndrome (HLHS)
We report two cases of successful biventricular repair following in-utero valvuloplasty. Case 1 presented at 28 weeks with a grossly dilated poorly contracting left ventricle (LV), signs of endocardial fibroelastosis, mild mitral regurgitation (MR) (2,9 m/s), critical AS (1,7 m/s), reversed flow in the aortic arch and ascites. Transabdominal percutaneous valvuloplasty resulted in antegrade flow in the aortic arch, ascites disappeared within 7 days. Until delivery at 35 weeks MR velocity increased to 4,5 m/s, aortic velocity to 3,9 m/s which was attributed to improved ventricular performance. Postnatal aortic valvuloplasty was unsuccessful in reducing the gradient, so a neonatal Ross-Konno procedure was carried out. At discharge there was normal LV size and function. Case 2 had almost aortic atresia (no measurable gradient) and a dysplastic mitral valve with moderate MR (4,8 m/s) but no ascites. Balloon dilation was performed at 33 weeks followed by antegrade aortic arch flow, trivial AR, a residual gradient of 36 mmHg and improved LV shortening. Valvuloplasty after delivery at 38 weeks again could not reduce the gradient, a Ross-Konno procedure with mitral valve repair was successful in establishing a biventricular circulation with good LV function.
Conclusions: These two cases confirm that in critical AS timely in-utero aortic valvuloplasty is able to improve left ventricular performance and fetal hemodynamics in a way that the likelihood of a postnatal biventricular repair is increased.

Presented at the 4th world congress of pediatrc cardiology and cardiac surgery, Buenos Aires 18 -22 September 2005:

Levosimendan – Drug of Choice for the Failing Immature Myocardium?
Lechner E, Moosbauer W, Pinter M, Mair R, Tulzer G
Children’s Heart Center Linz, Linz, Austria

Introduction: Levosimendan is a calcium sensitizer for the treatment of congestive heart failure (CHF). Levosimendan improved hemodynamics in adults with CHF. Data on the use of Levosimendan in premature infants with CHF following cardiac surgery is limited.
Case report: A 32 weeks gestational age, 1525 g premature male twin with transposition of the great arteries underwent arterial switch operation. Immediatly postoperatively he developed signs of low cardiac output. Mixed venous saturation was 56%, serum lactate increased to 14,8 mmol/l, systolic arterial pressure (SAP) was 40 mm Hg, left atrial pressure (LAP) was 24 mm Hg and echocardiography showed reduced left ventricular function with a fractional shortening of 10%. There were no signs of reduced coronary perfusion. Milrinone, dobutamine and epinephrine did not improve hemodynamics. Levosimendan was initiated at a dose of 0,05 yg/kg/min and increased to 0,1 yg/kg/min and 24 hours continously infused. Within 6 hours after starting the levosimendan infusion LAP decreased to 7 mm Hg, SAP increased to 60 mm Hg and within 24 hours after initiation serum lactate level decreased to 1,7 mmol/l and mixed venous saturation increased to 81%, echocardiography revealed improvement of left ventricular function with a fractional shortening of 25%. There were no side effects recognized during administration of levosimendan.
Conclusion: In premature neonates with postoperative low cardiac output syndrome due to failing myocardial function levosimendan seems to be a potent inotropic agent. Since hemondynamic effects and safety of levosimendan in neonates have not been investigated yet, its cautious use is recommended.

Closed or restrictive foramen ovale in hypoplastic left heart syndrome: a significant risk factor?
G Tulzer, R Mair, E Lechner, E Sames, W Arzt
Children’s Heart Center Linz, Linz, Austria

Although surgical results in children with hypoplastic left heart syndrome (HLHS) have substantially improved, there is still a significant mortality and morbidity. A restrictive or absent foramen ovale (FO) has been shown to cause significant impairment of pulmonary vessels. The purpose of this study was to compare outcome in patients with HLHS with restrictive or closed FO ovale to those with unrestrictive FO to test the hypothesis, that a restrictive FO is a significant risk factor.
Patients and Methods: Between 1997 and 2004 60 consecutive newborns with HLHS and intention to treat were admitted to our institution. In 14 patients (23%) a restrictive FO (<3mm with a mean gradient of 10 mm Hg or more by Doppler) was found (Group A). FO was completely closed in 3 of them. Group B consisted of 46 newborns with typical HLHS and non-restricitive FO. Both groups were comparable in terms of gestational age at birth, birthweight, sex, type of Norwood operation (RV/PA conduit, modified BT shunt) and length of follow-up.
Results: are shown in Table I. Despite prenatal diagnosis and postnatal emergency treatment all 3 patients with closed FO died immediatly after birth prior to surgery due to severe hypoxemia and pulmonary lymphangiectasia. There was no significant difference in survival between both groups, however patients of group A required significantly more and longer intensive care therapy after the Norwood operation and also after the modified Glenn procedure. Five patients with restrictive FO had procedures performed prior to stage I Norwood (surgical atrioseptectomy: 1, ballon atrioseptostomy: 4) to relieve pulmonary venous congestion. Patients of group A also had significantly more days of ventilation and days of NO therapy.
Conclusions: A closed FO in patients with HLHS was associated with preoperative death despite emergency treatment. Patients with restrictive FO had more postoperative (respiratory) problems, which could be handled with more and longer intensive care therapy. Despite there was no difference in short time survival, further studies must be performed to assess long term outcome.
Speculations: fetuses with HLHS and closed FO could be considered as possible candidates for in-utero atrioseptostomy to relieve pulmonary venous congestion and to prevent pulmonary lymphangiectasia.

Successful biventricular repair following in-utero balloon dilation of critical aortic stenosis
G.Tulzer, W.Arzt, R.Mair, E.Lechner, G.Geiselseder. Children’s Heart Center Linz. Linz. Austria
Critical aortic stenosis (AS) with reversed aortic arch flow in the mid-trimester fetus usually evolves into hypoplastic left heart syndrome (HLHS)
We report two cases of successful biventricular repair following in-utero valvuloplasty. Case 1 presented at 28 weeks with a grossly dilated poorly contracting left ventricle (LV), signs of endocardial fibroelastosis, mild mitral regurgitation (MR) (2,9 m/s), critical AS (1,7 m/s), reversed flow in the aortic arch and ascites. Transabdominal percutaneous valvuloplasty resulted in antegrade flow in the aortic arch, ascites disappeared within 7 days. Until delivery at 35 weeks MR velocity increased to 4,5 m/s, aortic velocity to 3,9 m/s which was attributed to improved ventricular performance. Postnatal aortic valvuloplasty was unsuccessful in reducing the gradient, so a neonatal Ross-Konno procedure was carried out. At discharge there was normal LV size and function. Case 2 had almost aortic atresia (no measurable gradient) and a dysplastic mitral valve with moderate MR (4,8 m/s) but no ascites. Balloon dilation was performed at 33 weeks followed by antegrade aortic arch flow, trivial AR, a residual gradient of 36 mmHg and improved LV shortening. Valvuloplasty after delivery at 38 weeks again could not reduce the gradient, a Ross-Konno procedure with mitral valve repair was successful in establishing a biventricular circulation with good LV function.
Conclusions: These two cases confirm that in critical AS timely in-utero aortic valvuloplasty is able to improve left ventricular performance and fetal hemodynamics in a way that the likelihood of a postnatal biventricular repair is increased.

Truncal Block Rotation – A New Option in DORV or TGA/VSD and Left Ventricular Outflow Tract Stenosis
E.Sames, R.Mair, E. Lechner, A.Hofer, G.Tulzer

BACKGROUND: The classical treatment option in DORV or TGA/VSD and left ventricular outflow tract (pulmonary or subpulmonary) obstruction is the Rastelli procedure. A long intraventricular tunnel bearing the risk of subaortic stenosis and a homograft conduit from the right ventricle to the pulmonary artery are potential problems of this procedure.
The aortic translocation (Nikaidoh) is an alternative method reported in some series, coming closer to a more anatomic repair. However,tension on the right coronary artery, affording its anterior translocation, and the lack of a pulmonary valve and a separate backwall of the pulmonary artery are disadvantages of this operation.
METHOD: A 5 yrs old boy with DORV, transposition of the great arteries, subpulmonary VSD and subpulmonary stenosis was referred to our unit after 5 palliative procedures which resulted in a common atrium, right classic Glenn and a stenotic pulmonary artery on the left side.
We performed a take-down of the Glenn and a complete repair using the principle of truncal block rotation without a homograft valve.
Both great arteries were divided, right and left coronay artery were excised and mobilized. The complete truncal block (aortic and pulmonary root en block) was excised including the conal septum, rotated by 180° and reimplanted. So the original aortic valve is positioned above the left ventricle. The VSD was closed and the coronaries reimplanted. Aorta and aortic root were reanastomosed. The pulmonary arteries were reconnected and reanastomosed to the pulmonary root anterior to the aorta. The original pulmonary valve, now located over the right ventricle, was bicuspid and was mobilized by a commissurotomy.
RESULT: The postoperative course was uneventful. He was on the ventilator for 8 hours, transferred to the normal ward on day 3 and discharged on day 13.There is no significant gradient across the pulmonary valve and no residual shunt.
CONCLUSION: In consent with other authors (Yamagishi et al., Haas et al.) we have demonstrated that the principle of truncal block rotation has the potential of complete anatomic repair in DORV or TGA/VSD and LVOT obstruction, especially when the LVOT stenosis is predominantly subvalvar.

Right ventricular to pulmonary artery shunt instead of modified Blalock Taussig shunt improves diastolic systemic and cerebral flow in newborns after the Norwood procedure

G.Tulzer, R Mair, R.Gitter, E Lechner, E Sames, G Geiselseder

Children’s Heart Center Linz, Department of Pediatric Cardiology

In newborns, who underwent a Norwood procedure due to a functionally univentricular heart combined with aortic arch hypoplasia, pulmonary blood flow is usually established via a modified Blalock Taussig shunt (BTS). The lower pulmonary vascular resistance causes a diastolic run-off into the pulmonary vascular bed, leading to low diastolic systemic pressures and thus decreased coronary perfusion pressure. Especially with large shunts, the single ventricle faces a decreasing coronary perfusion with increasing workload. This has been attributed to contribute to the early and late mortality and morbidity after stage I palliation. Placement of a right ventricular to pulmonary shunt (RV/PA) avoids this diastolic run-off and should therefore improve systemic diastolic flow. To assess differences in hemodynamics echocardiographic data of 16 newborns, who underwent a Norwood procedures was analyzed. 8 newborns with a BTS were compared to 8 newborns with RV/PA Shunt (5 mm diameter). Between the groups there was no significant difference in weight, preoperative complications or bypass time. There was no significant AV valve or pulmonary valve regurgitation except in 1 case with RV/PA Shunt. Echocardiography was carried out, when children were extubated and in a hemodynamically stable condition. There were no significant differences in ventricular inflow and outflow velocities or in shortening fraction. Doppler examination of descending aortic flow showed holodiastolic reversal of flow in all children with BTS but holodiastolic antegrade flow in 7/8 children with RV/PA Shunt. Doppler interrogation of the arteria cerebri anteror showed significantly lower pulsatility index due to higher enddiastolic and mean velocities in the group with RV/PA Shunts. Measured gradients across the RV/PA Shunt were 3,46 +/-0,7 m/s (mean +/- std dev) suggesting normal pulmonary artery pressures.
Right ventricular to pulmonary artery shunt instead of modified Blalock Taussig shunt improves diastolic systemic and cerebral flow in newborns after the Norwood procedure and should thus improve coronary and brain perfusion leading to a more stable hemodynamic situation after stage I palliation.