Fontan procedure


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Fontan procedure

  1. 1. Fontan procedure
  2. 2. <ul><li>The  Fontan procedure , or  Fontan/Kreutzer procedure , is a  palliative  surgical procedure used in children with complex  congenital heart defects . </li></ul><ul><li>It involves diverting the  venous   blood  from the  right atrium  to the  pulmonary arteries without passing through the morphologic  pulmonary ventricle . It was initially described in 1971 by Dr Fontan and Dr Kreutzer separately as a surgical treatment for  tricuspid atresia . </li></ul>
  3. 3. Indications <ul><li>The Fontan procedure has more recently been used in pediatric situations where an infant only has a single effective ventricle, either due to heart valve  defects (e.g. tricuspid or  pulmonary atresia ) or an abnormality of the pumping ability of the heart (e.g.  hypoplastic left heart syndrome ,  hypoplastic right heart syndrome ), or has complex congenital heart disease where a bi-ventricular repair is impossible or inadvisable. </li></ul>
  4. 4. <ul><li>Children with hypoplastic left heart syndrome have a single effective ventricle supplying blood to the lungs and the body (either from birth or after an initial surgery e.g.  Norwood procedure ). They are delicately balanced between inadequate blood supply to the lungs (causing  cyanosis ) and oversupply to the lungs (causing  heart failure </li></ul>
  5. 5. <ul><li>In addition, the single ventricle is doing nearly twice the expected amount of work (because it has to pump blood for both lungs and body). As a result, these children can have trouble gaining weight, and are also vulnerable to  decompensation  in the face of otherwise minor illnesses (even a common cold). Sometimes medications (e.g.  diuretics ) can help them through this stage. </li></ul>
  6. 6. <ul><li>Therefore, when either they are large enough, and if the pressure in the pulmonary arteries is low enough, these children (see example on  ) are referred for Fontan procedure commonly after 2 years of life. </li></ul>
  7. 7. Contraindications <ul><li>After Fontan, blood must flow through the lungs without being pumped by the heart. Therefore children with high  pulmonary vascular resistance  may not tolerate a Fontan procedure. Often  cardiac catheterization  is performed to check the resistance before proceeding with the surgery. </li></ul><ul><li>This is also the reason a Fontan procedure cannot be done immediately after birth; the pulmonary vascular resistance is high  in utero  and takes months to drop.) </li></ul>
  8. 8. Types <ul><li>There are three different types of Fontan procedure: </li></ul><ul><li>Atriopulmonary connection (the original) Described by Fontan and Kreutzer. </li></ul><ul><li>Intracardiac total cavopulmonary connection (lateral tunnel) </li></ul><ul><li>Extracardiac total cavopulmonary connection </li></ul>
  9. 9. Approach <ul><li>The first stage, also called a  Bidirectional Glenn procedure  or  Hemi-Fontan  (see also  Kawashima procedure ), involves redirecting oxygen-poor blood from the top of the body to the lungs. That is, the pulmonary arteries are disconnected from their existing blood supply (e.g. a shunt created during a  Norwood procedure , a  patent ductus arteriosus , etc). The  superior vena cava  (SVC), which carries blood returning from the upper body, is disconnected from the heart and instead redirected into the pulmonary arteries. The  inferior vena cava  (IVC), which carries blood returning from the lower body, continues to connect to the heart. </li></ul>
  10. 10. <ul><li>At this point, patients are no longer in that delicate balance, and the single ventricle is doing much less work. They usually can grow adequately, and are less fragile. However, they still have marked  hypoxia  (because of the IVC blood that is not fed into the lungs to be oxygenated). Therefore most patients are referred for another surgery. </li></ul>
  11. 11. <ul><li>The second stage, also called  Fontan completion , involves redirecting the blood from the IVC to the lungs as well. At this point, the oxygen-poor blood from upper and lower body flows through the lungs without being pumped (driven only by the pressure that builds up in the veins). This corrects the hypoxia, and leaves the single ventricle responsible only for supplying blood to the body. </li></ul>
  12. 12. Post-operative complications Early <ul><li>children can have trouble with  pleural effusions , fluid building up around the lungs. This can require a longer stay in the hospital for drainage with  chest tubes . To address this risk, some surgeons make a fenestration (a small hole) from the venous circulation into the atrium. When the pressure in the veins is high, some of the oxygen-poor blood can escape through the fenestration to relieve the pressure. However, this results in  hypoxia , so the fenestration may eventually need to be closed by an  interventional cardiologist . </li></ul>
  13. 13. Late Complications <ul><li>Children can have trouble with  atrial flutter  and  atrial fibrillation  because of scarring in the atrium, especially if the connection of IVC to pulmonary arteries involved an intracardiac baffle (instead of an extracardiac conduit). This sometimes requires treatment such as  radiofrequency ablation . There are other long-term risks, including  protein-losing enteropathy  and  chronic renal insufficiency , although understanding of these risks is still incomplete. Some patients require long-term  blood thinners . </li></ul>
  14. 14. <ul><li>The Fontan procedure is palliative, not curative. </li></ul><ul><li>But in many cases it can result in normal or near-normal growth, development, exercise tolerance, and good quality of life. </li></ul><ul><li>  In some cases, patients will eventually require  heart transplantation </li></ul>