Pulmonary Atresia and Intact Ventricular Septum

Seoul National University Hospital

Department of Thoracic & Cardiovascular Surgery

Pulmonary Atresia and Intact Ventricular Septum

1. Definition Congenital malformation in which pulmonary valve is atretic,

coexisting with variable degrees of RV & TV hypoplasia

2. Historical Note Hunter : 1st case report in 1783

Peacock : Collected 7 patients report in 1839

Grant : Coronary sinusoid & fistula recognized in 1926

Davignon : Suggest systemic-pulmonary artery shunt in 1961

Bowman : Shunt and RV outflow operation in 1971

PA+IVS

Pathophysiology• Atretic pulmonary valve combined with

varying degrees of tricuspid valve and right ventricular hypoplasia, leading to inadequate pulmonary blood flow(supported by PDA) and hypoxia.

• Right ventricular-to-coronary artery fistulae are seen in 50~60% of patients, resulting in a right ventricular-dependent coronary circulation in 10~20%

Surgical Morphology of PA+IVS

1. Pulmonary valve : remnant fibrous component 2. Pulmonary artery : usually normal in size 3. Right ventricle Variable, enlarged in 5%, severely reduced capacity in 60 % Ebstein malformation & severe TR in enlarged thin RV. Diffuse fibrosis of hypertrophied small RV & fibroelastosis 4. RV-coronary fistula Coronary sinusoid in 50%, dependent circulation in 10% 5. Tricuspid valve : always abnormal 6. Right atrium Intraatrial communication in all cases, & enlarged 7. Left-sided chambers LV compliances is depressed in many cases. LA enlarged & hypertrophy 8. Coexisting cardiac anomalies ; uncommon

RV-Coronary Artery Fistula

Clinical Features & Diagnosis

1. Symptoms & signs Cyanosis after birth & becomes rapidly more severe

as the ductus closes, respiratory distress, metabolic acidosis,

Absence of RV impulse, no typical murmur

2. Chest radiography Diminished (or normal) vascular marking

3. Electrocardiography Prominent right atrial P-wave ( RA enlargement )

4. Echocardiography

5. Cardiac catheterization & cineangiography

Natural History of PA+IVS

1. Incidence Uncommon malformation 1~1.5% of CHD 3% of critically ill infants with CHD

2. Survival 50% survival in 2weeks of life 15% survival in 6months of life

3. Modes of death Severe hypoxia & metabolic acidosis (Coincides with spontaneous closure of PDA) Rarely survival into young adult life

Technique of Operation for PA+IVS

1. Concomitant placement of patch & shunt 2. Isolated procedure Valvotomy only Placement of transannular patch Systemic-pulmonary artery shunt only

3. Definitive procedures Separated two-ventricle repair Single-ventricle repair ( Fontan )

*One & a half ventricle repair

Overhauling RV cavity

Operation for PA+IVSConcomitant placement of patch & shunt

PA + IVS – Hemi Fontan

PA + IVS – Hemi Fontan Alternative Method

Lateral Tunnel with Fenestration

Surgical Results of PA+IVS

1. Survival Early death Time-related survival 2. Modes of death 3. Incremental risk factors for death 1) Dimension of TV 2) RV dependent coronary circulation 3) Systemic-pulmonary shunt 4) Birth weight 4. Interim Intervention after the initial procedure Transannular patch is better than valvotomy 5. Definitive procedures ; two ventricle repair

Surgical Indications of PA+IVS

• The presence of the malformation is generally an indication for operation because of highly lethal nature of the condition. As soon as diagnosis is suspected,

neonate is intubated, and an infusion of PGE1 is begun.• Selection of the initial intervention is based in large part on estimated probability( Z value, -3 ) that a separated two-ventricle system will ultimately be possible• The initial goals of correction are to improve pulmonary blood flow with a systemic-to- pulmonary shunt & to promote RV development by relieving RVOTO

Special Situation & Controversies

1. Percutaneous valvotomy Laser valvotomy followed by balloon dilatation 2. Formalin infiltration of ductus arteriosus 3. Right ventricle to aorta conduit 4. Tricuspid valve closure in RV-coronary fistula 5. Tricuspid valve growth - TV and RV cavity tend to increase in size as the patients grow with forward flow across valve. - With growth of RV, fistulae may disappear. - Abnormality of RV compliance usually remains.