Palliative procedures

Systemic and Venous Shunts to Augment Effective Pulmonary Blood Flow

systemic shunt from aorta or branch of it to PA to increase oxygen saturation:

Blalock–Taussig (BT) shunt

Originally sacrificed subclavian artery (with distal ligation) and proximal portion routed with end to side anastomosis with branch PA.

Modified, synthetic graft between subclavian and pulmonary arteries. Allow better growth of the pulmonary arterial tree and less distortion of anatomy.

Indications: right-sided cardiac obstruction or hypoplasia, such as RVOTO, pulmonary stenosis or atresia as ToF, to increase the pulmonary blood flow.

Complications: Ipsilateral PA enlargement,  LV hypertrophy, pseudo-aneurysm, infected shunt, shunt stenosis and seroma around graft

Due to lower PVR relative to systemic vascular resistance, continuous flow into BT shunt, during diastole not only systole, resulting in lower systemic diastolic blood pressure and “coronary steal” decreased myocardial perfusion.

Davidson or Central shunt

Gore-Tex shunt graft anastomose ascending aorta to PA.

Indications: TGA, VSD with RVOTO, pulmonary atresia, and PA stenosis/ hypoplasia.

Complications: shunt thrombosis, PA stenosis/ distortion at anastomotic site, and congestive heart failure as a result of excessive pulmonary blood flow.

Waterston–Cooley shunt

Between posterior wall of ascending aorta and anterior wall of right PA to improve pulmonary perfusion. No longer performed.

Indications: diminished pulmonary flow, such as pulmonary atresia, ToF with RVOTO and tricuspid atresia.

Complications: shunt obstruction, kinking, narrowing, thrombosis, preferential distribution of shunt flow to right lung with PA distortion and embolism.

Potts shunts

Shunt between descending thoracic aorta and left PA. No longer performed.

Indications: patients with TOF prior to defect repair. Doesn’t relieve RV outflow obstruction, but improves pulmonary blood flow and cyanosis.

Damus–Kaye–Stansel shunt

Main PA transected and connected to ascending aorta by end-to-side anastomosis.

Indications relieve systemic ventricular outflow tract obstruction in patients with DORV, univentricular heart with subaortic stenosis and TGA with VSD.

Patients have cavopulmonary shunts to return systemic venous blood to pulmonary circulation.

Complications pulmonary valve regurgitation.

Venous shunts, not performed in neonates because of elevated pulmonary resistance, used to increase pulmonary blood flow after infants are 3 months old.

Sano procedure

Extracardiac conduit between RV & PA.

Indications include HLHS, DORV with aortic or subaortic stenosis and aortic atresia.

Elimination of "coronary steal" phenomenon. Forward flow through shunt only occurs during systole. Improved hemodynamic stability postoperatively compared to modified BT shunt.

Complications

Thrombosis or occlusion. Branch PA stenosis. Aneurysm/pseudoaneurysm at ventriculotomy site

Glenn shunt

Classic (unidirectional), distal end SVC is ligated, and side SVC above ligation is anastomosed with distal end of divided right PA, providing unilateral (right) lung perfusion.

Modified (bidirectional), between transected end of SVC and side of undivided right PA, providing balanced bilateral pulmonary circulation.

Indications palliation cyanotic CHD that eventually lead to a single anatomical or functional ventricle (i.e. tricuspid atresia), right or left ventricular hypoplasia (i.e. HLHS).

First stage in early childhood before Fontan, given disproportionate blood flow of SVC in early part of life. As child grows, blood flow from lower body increases disproportionately to SVC flow, mandating follow-up Fontan.

Complications SVC syndrome, shunt and PA thrombosis, stenosis, sinus node injury, pulmonary AVM and aortopulmonary collaterals. Decreased diameter in contralateral PA. Development of decompressing venous collaterals (SVC-to-IVC), resulting in reduced oxygen saturation.

Hemi-Fontan procedure,

Similar to Glenn, except continuity of SVC & RA maintained, second anastomosis of caudal SVC with inferior right PA.

Patch of homograft tissue sewn across superior cavoatrial junction preventing systemic venous return from upper body into RA.

Simplifies subsequent lateral tunnel Fontan completion as continuity of RA & SVC maintained.

Kawashima procedure

Cavopulmonary anastomosis bidirectional Glenn shunt between SVC and PA in patient with interruption of IVC and azygous extension to SVC.

Left-sided Kawashima is anastomosed to left branch PA.

Indications left isomerism heterotaxy syndrome, single functional ventricle, single atrium and common atrioventricular valve with or without regurgitation, PS.

Redirects all systemic venous blood to lungs except hepatic and coronary venous return.

Complications thrombosis or stenosis mild cyanosis because desaturated hepatic venous blood is pumped along with pulmonary venous blood to the body. Multiple microscopic pulmonary AVMs. This will resolve following surgical redirection of hepatic veins into cavopulmonary circulation (total right heart bypass operation).

Separation of Systemic and Pulmonary Circulations:

Fontan shunt

Classic, between RA or atrial appendage and PA (atrio-pulmonary connection) using a homograft, patch, or valved conduit.

Lateral tunnel (intra-atrial tunnel), right atrial wall used to create baffle to direct blood flow from IVC to lower portion of SVC, which is further drained to PA.

Extra-cardiac conduit, No atrial-pulmonary connection is established. IVC is divided at inferior cavoatrial junction, and defect at inferior RA is closed. Synthetic conduit used to connect transected IVC to inferior aspect of right PA. Conduit courses adjacent to the RA.

Maintaining normal RA as possible to avoid arrhythmia, but prone to conduit-complications.

Total cavopulmonary connection includes either lateral tunnel or extra-cardiac Fontan, combined with modified Glenn shunt, while pulmonary trunk is disconnected from heart and right and left PAs are interconnected.

Fenestrated, communication between Fontan conduit and RA to reduce systemic venous pressure in post-operative period, serving as a “pop-off” valve to increased pulmonary pressure (right-to-left shunt).

Indications cyanotic CHD with anatomical or functional single ventricle such as tricuspid atresia, pulmonary atresia with intact ventricular septum, DOLV, HLHS and unbalanced AVSD.

Complications fluid collection around external conduit PA stenosis, thrombosis, pulmonary thromboembolism, RA enlargement, atrioventricular valve regurgitation, cavopulmonary anastomotic narrowing, pulmonary AVM, and MAPCAs. Alterations in venous pressure result in pleural effusion and protein-losing enteropathy.

Norwood procedure

Indications palliate single ventricle HLHS.

Utilize single RV as systemic pump & reconstruct systemic arterial outflow. Ensure pulmonary venous return to right heart. Reroute systemic venous return directly to lungs.

Stage 1 Neoaorta constructed using divided main PA anastomosed to aortic root. BT or Sano shunt created to provide blood flow to high-resistance pulmonary arterial circulation. Ductus arteriosus ligated. Atrial-septum resected.

Stage 2 BT or Sano shunt excised. Bidirectional Glenn shunt created

Stage 3 Lateral tunnel or extracardiac Fontan procedure performed.

Complications Distal aortic arch narrowing, mediastinitis, shunt thrombus, collaterals, & effusions.

Rastelli procedure

External RV to PA conduit and intraventricular LV to aorta via VSD tunnel created. The pulmonary valve may be atretic and is surgically closed at the time of the procedure.

Indications DORV, TGA with VSD and LVOT obstruction, and rarely ToF with PS or atresia.

Complications

Leakage, obstruction, calcification, stenosis, or aneurysm. Branch PA stenosis and biventricular dysfunction.

CTA used to conduit patency, calcification, stenosis and distance between the back of sternum and mediastinal vessels/heart chambers and conduit for pre-surgical planning of re-operation.

Pulmonary artery banding

Palliative restriction of increased pulmonary perfusion in excessive left-to-right shunting who cannot undergo corrective surgery.

Placed in mid portion of pulmonary trunk to avoid injury to pulmonary valve.

Indications cyanotic CHD such as complicated VSD, multiple VSDs, VSD with coarctation of aorta, HLHS and D-TGA to prevent pulmonary over-circulation leading to eventual pulmonary arterial hypertension, and subsequent right ventricular failure.

Complications branch PA stenosis, migration, PA pseudo-aneurysm, fibrosis and scarring of the band site, and sub-aortic narrowing.

Unifocalisation

Reroute misdirected blood vessels of MAPCAs into single vessel (or into PA if present), which is then attached to RV through conduit.

Indications VSD and pulmonary atresia, ToF with pulmonary atresia, single ventricle, right isomerism and severely unbalanced common atrioventricular canal (CAVC).

Complications thrombosis, calcification and stenosis of conduit.

Corrective procedures

Revising Transposed Outflow Tracts

Arterial switch repair

Indications: correction of TGA by atrial baffle (Mustard uses pericardial tissue or a Gore-Tex graft, in Senning, atrial septum is reconstructed to form baffle) redirects systemic venous blood through mitral valve to LV (sub-pulmonary), and oxygenated pulmonary venous return through tricuspid valve to RV (sub-aortic).

Complications: leakage, obstruction, RV hypertrophy, caval and pulmonary venous obstruction and dilatation of great arteries.

Jatene arterial switch procedure

Procedure of choice for D-TGA in neonates, aorta and main PA transected above corresponding valves and switched so distal aortic segment anastomosed with proximal pulmonary root to form a neoaorta. Distal PA brought anterior to neo-aorta (the Lecompte manoeuvre) to anastomose with proximal aortic root to form neopulmonary artery.

Coronary arteries re-implanted to neo-aorta.

Complication PA stenosis, inadequate growth of the PAs, aortic root dilation, RV outflow obstruction, supravalvular aortic stenosis, and ischaemic complications because of coronary artery translocation.