In tricuspid atresia, the right atrium fails to open into right ventricle through a right atri~ventricular valve. It is often associated with a ventricular septal defect.Very often there is associated pulmanary valve atacsia al- stenosis at vnlvar or infundibular level. h about 15 per cent of cases there is increased pulmonary flow and its associated eamplications. Tricuspid atresia could also be associated with discord,mt ventiicwlo 'uteiial connection (transposition of great arteries).
Single Ventricle Physiology
In complete correction of a congenital cardiac condition, it is ideal to have two-ventricle correction. (Pulmonary ru~d systemic ventricles supporting t~vo circulations). When this is inlpassit~le or inadvisable, surgeon aims for one ventricle car-rection. The underlying condition may be tricuspid ntresia and number of other conditions with univentriculu AV connection. The basic surgical correction is achieved by Fontan operation or one of its numerous modifications.The principle of this aperatinn is direct ehru~neling of systemic venous drainage into the pulmonary artery bypassing the RV. There are some conditions where a surgeon has to perform Fontan procedure in stages.
Indications for Operation
The operation is indicated in patients with single ventricle physiology. Fontan operation is also indicated in patients with coneosdmt or discordant i~trio ventricular connection in whom ane ventricle is too small or dysplastic. Fontan type carreetian is also indicated even when there are two adequate ventricles but eannat he separated because of complex overriding AV valves (straddling AV valves), relationship of VSDs and great arteries.
Fontan Operation
The original Fonlan operation was done in a case where classical Glenn operation had been done (end-Lo-end anastomosis of superior veila cava and light pulmonary artery). The Fontan operation was completed by inserting a biological valve in the IVC - RA juilction and a valved conduit between sight atrium and p u l n l o n ~ y artery. Later on Foiltan operation was done diverting both SVC and IVC blood from right atrium through the conduit to pulmonsuy artely without valves. There have been many ~nodifications of Fontan procedure. Currently the procedure of choice is total cavopulmonary connection (TCPC).Total Cavo Pulmonary Con~zection (TCPC)-Lateral Tunnel Operation (Marc de Leval) (1988)
Cardiopulinonary bypass is instituted by cannulation of ascending aorta, SVC innominate vein junction and IVC at diaphragmatic level. Patient is cooled down and on total cardiopulmonary bypass aorta clamped and heart ai-rested by infusion of cold cardioplegia. The right atrium is opened. The pulmonary trunk is transected and proximal end over'sewn. The distal end of pulmonary trunk is also doubly sutured. The superior vena cava is transected as it crosses right pulmonary artery. Azygos vein is ligated and divided. The upper divided end of SVC is anastornosed to the superior aspect of right pulnionary artery as in bi-directional Glenn operation. The lower end of divided SVC is then anastomosed to under aspect of light pulmonary artery. The anastomosis is made as wide as possible. Attention is then concentrated to make a lateral tunnel inside right atrium to divert the entire inferior' vena caval blood through the superior vena caval inlet on to the right pulmonary artery. A PTFE (Goretex) graft is cut open and appropriately shaped to form part of the lateral tunnel. Right atrial wall completes the other wall of the tunnel. Atrial septa1 defect is enlarged in u~liventricular heart where the right AV valve is the main inlet. The coronary sinus drains into the lower pressured left atrium.
Extra Cardiac Conduit Fontarz
This can be done with or witllout cardiopulinona~y bypass. First step is to make a bi-directional Glenn shunt. The main pulmona~y artery is clamped, transected and both ends sutured off. A wide anastomosis is made between a PTFE graft and under aspect of right pulmonary artery and on to nlain pullnonary artery. Tile graft is then clamped at its mid portion. IVC is mobilised and taped. Very low IVC cannulation is doiie after full hep'arinisation (3 mgIKg) and it is connected to another cannula in the right atrial appendage to forin a shunt for IVC blood to flow to atrium. IVC is doubly clamped and its cardiac end over sewn. The end of the conduit is then anastomosed to the cut lower end of IVC to complete the extra cardiac conduit. For decompression, an anastomosis tneasu~ing 4,5 or 6 inm can be made between the conduit and right atrium. This can also be done using a Goretex graft of the same dimension sutured to RA on one side and the extra cardiac conduit on the other.
Results of Operation
Bidirectional Superior Cnvopulrnonary Shunt-Bidirectional Glenn SIzunt Hospital mortality is between 5 and 10 per cent. Early palliation is vely good with arterial saturation around 85 per cent. one year survival is reported as 90 per cent and five year as 80 per cent. Most patients undergo a second operation to complete modified Fonttan operation (Total cavopulmonary connection - TCPC).
Fontan Operation and Modifications
Earlier reported to have 20 per cent mortality, it has come down to five per cent in specialized centers. In the earlier series the 5, 10 and 15 year suivival was 70,65 and 50 per cent. In the current era, the survival for bi-directional Glenn followed by modified Fontan operation at the end of five years is around 90 per.cent. Even under ideal conditions the 15-year survival is only 73 per cent and a slow rising hazard is ever present. That is why, unlike repair of Tetralogy, whichis considered curative, Fontan procedure sllould be considered only as'excellent palliation.
Single Ventricle Physiology
In complete correction of a congenital cardiac condition, it is ideal to have two-ventricle correction. (Pulmonary ru~d systemic ventricles supporting t~vo circulations). When this is inlpassit~le or inadvisable, surgeon aims for one ventricle car-rection. The underlying condition may be tricuspid ntresia and number of other conditions with univentriculu AV connection. The basic surgical correction is achieved by Fontan operation or one of its numerous modifications.The principle of this aperatinn is direct ehru~neling of systemic venous drainage into the pulmonary artery bypassing the RV. There are some conditions where a surgeon has to perform Fontan procedure in stages.
Indications for Operation
The operation is indicated in patients with single ventricle physiology. Fontan operation is also indicated in patients with coneosdmt or discordant i~trio ventricular connection in whom ane ventricle is too small or dysplastic. Fontan type carreetian is also indicated even when there are two adequate ventricles but eannat he separated because of complex overriding AV valves (straddling AV valves), relationship of VSDs and great arteries.
Fontan Operation
The original Fonlan operation was done in a case where classical Glenn operation had been done (end-Lo-end anastomosis of superior veila cava and light pulmonary artery). The Fontan operation was completed by inserting a biological valve in the IVC - RA juilction and a valved conduit between sight atrium and p u l n l o n ~ y artery. Later on Foiltan operation was done diverting both SVC and IVC blood from right atrium through the conduit to pulmonsuy artely without valves. There have been many ~nodifications of Fontan procedure. Currently the procedure of choice is total cavopulmonary connection (TCPC).Total Cavo Pulmonary Con~zection (TCPC)-Lateral Tunnel Operation (Marc de Leval) (1988)
Cardiopulinonary bypass is instituted by cannulation of ascending aorta, SVC innominate vein junction and IVC at diaphragmatic level. Patient is cooled down and on total cardiopulmonary bypass aorta clamped and heart ai-rested by infusion of cold cardioplegia. The right atrium is opened. The pulmonary trunk is transected and proximal end over'sewn. The distal end of pulmonary trunk is also doubly sutured. The superior vena cava is transected as it crosses right pulmonary artery. Azygos vein is ligated and divided. The upper divided end of SVC is anastornosed to the superior aspect of right pulnionary artery as in bi-directional Glenn operation. The lower end of divided SVC is then anastomosed to under aspect of light pulmonary artery. The anastomosis is made as wide as possible. Attention is then concentrated to make a lateral tunnel inside right atrium to divert the entire inferior' vena caval blood through the superior vena caval inlet on to the right pulmonary artery. A PTFE (Goretex) graft is cut open and appropriately shaped to form part of the lateral tunnel. Right atrial wall completes the other wall of the tunnel. Atrial septa1 defect is enlarged in u~liventricular heart where the right AV valve is the main inlet. The coronary sinus drains into the lower pressured left atrium.
Extra Cardiac Conduit Fontarz
This can be done with or witllout cardiopulinona~y bypass. First step is to make a bi-directional Glenn shunt. The main pulmona~y artery is clamped, transected and both ends sutured off. A wide anastomosis is made between a PTFE graft and under aspect of right pulmonary artery and on to nlain pullnonary artery. Tile graft is then clamped at its mid portion. IVC is mobilised and taped. Very low IVC cannulation is doiie after full hep'arinisation (3 mgIKg) and it is connected to another cannula in the right atrial appendage to forin a shunt for IVC blood to flow to atrium. IVC is doubly clamped and its cardiac end over sewn. The end of the conduit is then anastomosed to the cut lower end of IVC to complete the extra cardiac conduit. For decompression, an anastomosis tneasu~ing 4,5 or 6 inm can be made between the conduit and right atrium. This can also be done using a Goretex graft of the same dimension sutured to RA on one side and the extra cardiac conduit on the other.
Results of Operation
Bidirectional Superior Cnvopulrnonary Shunt-Bidirectional Glenn SIzunt Hospital mortality is between 5 and 10 per cent. Early palliation is vely good with arterial saturation around 85 per cent. one year survival is reported as 90 per cent and five year as 80 per cent. Most patients undergo a second operation to complete modified Fonttan operation (Total cavopulmonary connection - TCPC).
Fontan Operation and Modifications
Earlier reported to have 20 per cent mortality, it has come down to five per cent in specialized centers. In the earlier series the 5, 10 and 15 year suivival was 70,65 and 50 per cent. In the current era, the survival for bi-directional Glenn followed by modified Fontan operation at the end of five years is around 90 per.cent. Even under ideal conditions the 15-year survival is only 73 per cent and a slow rising hazard is ever present. That is why, unlike repair of Tetralogy, whichis considered curative, Fontan procedure sllould be considered only as'excellent palliation.
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