TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION

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TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION

• CJ JORDAAN
• 29/01/04

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Definition

• Uncommon congenital cardiac defect (1-3) in
  which there is no direct communication between
  the pulmonary venous drainage and the Left
  Atrium.
• All the pulmonary veins connect/drain to the
  Right atrium.

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Embryology

• Total anomalous pulmonary venous connection
  (TAPVC) develops when the primordial pulmonary
  vein fails to unite with the plexus of veins
  surrounding the lung buds.
• This results in return of pulmonary venous blood
  to the heart via a systemic vein, and
  subsequently to the right atrium.

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Classification

• TAPVC is classified according to the site of
  connection
• Supra cardiac includes connections to the left
  Innominate vein, the SVC, or the Azygos
• Cardiac includes connections to the coronary
  sinus or directly to the right atrium
• Infra cardiac includes connections below the
  diaphragm to the portal vein, hepatic veins,
  ductus venosus or IVC.
• Mixed involves connections of two or more of
  these types at least one of the main lobar
  pulmonary veins is draining differently from the
  others
• Each category can be further classified as
  obstructive or non-obstructive.

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1. Supra cardiac TAPVC

• Most common form of TAPVC---45
• Bilat draining of pulmonary veins (PV) to Common
  Pulmonary Venous Sinus (CPVS).
• This confluence drains via Vertical Vein (VV) to
  Innominate vein, SVC or Azygos.
• Stenosis common ( /- 40-60)
• Pulmonary vein systemic connection,
• Vascular vice or
• Long thin VV

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-CPVC locationSupra cardiac TAPVC
-Sites of stenosis

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2. Cardiac TAPVC

• Accounts for 25 of TAPVC
• VV drains mostly to Coronary Sinus, seldom
  directly to Right atrium.
• Enlarged coronary sinus acts as the CPVS with
  only a thin wall of myocardium separating sinus
  and the Left atrium.
• Right atrial draining Seen in RA isomerism.
  Associated with absent Coronary sinus, huge or
  absent intra atrial septum. VV opens as a
  fibrous midline confluence.
• STENOSIS Rare. May occur where the CPVS joins
  the Coronary sinus, or at the mouth of the
  coronary sinus (persisting Thebesian valve)

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3. Infra cardiac TAPVC

• Accounts for 25 of TAPVC
• The common pulmonary vein drains through the
  diaphragm to the portal vein, ductus venosus or
  seldom to the IVC.
• Has the greatest propensity for STENOSIS
• -May be compressed where it penetrates the
  Diaphragm,
• -Connecting vein is narrowed at its junction
  with the portal vein,
• -VV has a thickened wall with intimal
  proliferation,
• -portal sinusoids (Liver) offer additional
  obstruction to venous return

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Infra cardiac TAPVC
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4. Mixed APVC

• Involves a combination of connections of two or
  more of the subtypes (at least one of the main
  lobar pulmonary veins is draining differently
  from the others.)

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Anatomy

• RA Enlarged and thick walled. Decreased
  compliance.
• LA Volume 53 less than predicted. LA auricle is
  normal in size, decrease in LA can be explained
  by the absence of the pulmonary vein component.
• ASD ASD or PFO must exist for survival. Usually
  of adequate size and not obstructive. Obstruction
  leads to a decreased R to L shunt with pulmonary
  venous obstruction and Pulm. Hypertension.
  Presents as a severely sick neonate.

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Anatomy

• LV Normal in size, wall thickness and mass, but
  decreased LV cavity ( due to leftward
  displacement of septum secondary to right
  ventricle pressure-volume overload.)
• RV Varies in size, depends on magnitude of
  pulmonary blood flow, pulmonary venous stenosis,
  point of PV connection. (Infra cardiac
  connection- RV not dilated or hypertrophied)
• PA Most infants have marked pulmonary
  hypertension. Structural changes are usually
  found in the lungs even in the youngest infants
  dying of TAPVC. Increase in pulm. Arterial
  muscularity-increase in wall thickness and
  extension of muscle into smaller and peripheral
  arteries. Vein wall thickness is also increased.

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Pathophysiology

• All pulmonary venous blood returns to the right
  atrium. (common mixing chamber)
• A right-to-left shunt at the atrial level (-RV
  compl, ASD size, Rp)
• Increased pulmonary blood flow and pulmonary
  venous obstruction will eventually result in
  pulmonary hypertension.
• Infra diaphragmatic draining.

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Pathophysiology

• Pulmonary vein stenosis
• Obstruction to pulmonary draining with increase
  in pulm. venous pressure.
• Capillary leak with interstitial edema.
• Reflex pulm. vaso constriction and progressive
  increase in Rp pulmonary hypertension.
• Increased PAP leads to increased RV pressures
  (sometimes supra systemic) with RV failure,
  decreased pulm. blood flow, decreased QpQs,
  decreased systemic SAT, peripheral hypoxia and
  metabolic acidosis with multi organ failure.
• PFO obstruction Increased LAP, impedes pulm.
  venous return, producing pulm. hypertension.

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Burchell principle

• A direct relationship exists between the
  magnitude of pulm. blood flow and systemic
  saturation.
• The QpQs is determined by magnitude of pulmonary
  blood flow, pulm. blood flow is inversely related
  to Rp.
• Thus an increase in PAP and Rp leads to a
  decrease in pulm blood flow with a decreased
  systemic SAT.
• SAT less than 80 QpQs likely to be lt 1.4 and
  Rp gt 10 !!!!!!!

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Clinical features

• Clinical features are determined by the degree of
  pulmonary venous obstruction.
• If obstruction is severe, infant will be
  critically ill with tachypnea, hypoxemia, and
  metabolic acidosis. Cyanosis can be unimpressive
  to severe, this is a surgical emergency.
• Prognosis 50 die within 3 weeks, 75 at 5
  weeks and 100 at 8-12 weeks
• No obstruction Not so critically ill. May
  present later with pulmonary hypertension,
  cardiomegaly, large pulm blood flow. Patients
  surviving first year of life present with failure
  to thrive, severe growth retardation, mild
  cyanosis. Stable hemodynamic state with
  progressive pulmonary hypertension and
  development of Eisenmenger in their twenties.

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Diagnosis

• CXR
• Shows ground glass (diffuse alveolar pattern) or
  "snowman" appearance from persistent vertical
  vein, small heart pulm stenosis.
• No stenosis Large heart with increased pulm
  blood flow.

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• There is cardiomegaly with increased pulmonary
  arterial markings. There is dilation of both the
  left and right innominate veins and the right
  superior vena cava producing the classical
  "snowman" or "figure of 8" appearance. The
  superior mediastinum is enlarged secondary to
  dilation of the right vena cava, innominate vein
  and ascending vertical vein.

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Neonate no stenosis
Neonate with stenosis
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Diagnosis

• Echo
• Diagnostic in most infants.
• Evaluation of cardiac chambers, Echo free space
  posterior to LA with abnormal drainage

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Diagnosis

• Angiography

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Diagnosis

• MRI angiogram

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TREATMENT

• Patients with TAPVC should undergo operative
  repair when the diagnosis is made
• Obstructed TAPVC is a surgical emergency
• Non-obstructed TAPVC should have prompt repair as
  well, as the clinical status of these patients
  can deteriorate rapidly
• Early repair of non-obstructed TAPVC also
  prevents the adverse squeal of cyanosis and
  volume overload of the heart and lungs

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Treatment

• Pre operatively
• Admit in PICU
• Intubation and ventilation
• Tolazoline, PGE1 IVI
• Stabilize, correct metabolic acidosis, confirm
  diagnosis
• Prepare for emergent theatre.

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Operative Technique

• Cardiopulmonary bypass with hypothermic
  circulatory arrest is the preferred approach in
  critically ill infants
• Surgical goals are eliminating all anomalous
  connections, draining the pulmonary veins into
  the left atrium, and closing intracardiac shunts,
  small PFO is left for RV decompression
• The PV-LA anastomosis must be large and
  undistorted .
• Problems Small aorta
• Hypothermic CPB response

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• Left SVC connection Ligate left-sided vertical
  vein at junction with Innominate vein Open left
  atrium and incise the posterior wall Find and
  incise the anterior wall of the confluence
  Anastomose the pulmonary venous confluence to the
  left atrium Close PFO or ASD through left
  atrium or through separate right atrial incision
• Right SVC connection Expose pulmonary venous
  confluence and anastomose to left atrium as
  above Ligate anomalous connections or patch
  from within SVC A baffle may be used instead to
  channel flow from the right SVC through an
  enlarged interatrial connection
• Azygos connection Ligate anomalous connection
  Anastomose confluence to left atrium as above

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2. Cardiac Type

• Coronary sinus connection
• Classic repair Create common large interatrial
  connection by incising coronary sinus septum and
  septum primum Close this new defect with a
  single patch all pulmonary venous return and
  coronary sinus return now drains into the left
  atrium
• Van Praag
• Right atrium connection Enlarge interatrial
  connection Create baffle to direct flow from
  pulmonary venous opening across interatrial
  connection

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3. Infracardiac Type

• Ligate PDA once CPB is established Identify
  and ligate anomalous descending vertical vein at
  the diaphragm Initiate circulatory arrest
  Open left atrium and incise the posterior wall
  Find and incise the anterior wall of the
  confluence Anastomose the pulmonary venous
  confluence to the left atrium Close the
  interatrial communication

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4. Mixed Type

• Problems with Mixed Type No pulmonary venous
  confluence Requires 2 or more anastomosis
  Smaller anastomosis predispose to pulmonary
  venous obstruction Risk of mortality and late
  pulmonary venous obstruction is increased
  Operative repair probably not curative

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Post operative

• Pulmonary hypertensive crisis.
• Sedation, ventilation, Fentanyl analgesia
• Pco2 (lt30mmHg) and high PO2
• TNT, PGE1, Dobutamine, Tolazoline, Adrenaline
  etc..
• Results Early (hospital) mortality ranges from
  2-20 90 of patients are cured 5-10 have
  late failure of repair due to pulmonary venous
  obstruction
• LA size adequate due to incorporation of PVC into
  LA

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Post operative

• Risk Factors Poor pre-operative status
  (acidosis) Pulmonary venous obstruction, small
  PFO
• High pulmonary vascular resistance, pre
  operative SAT lt80 Young age Small left
  ventricle Major associated anomalies
  Infracardiac or mixed type

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Literature

• BuLock FA et al. Balloon dilatation of vein
  stenosis in obstructed TAPVC. Ped Cardio
  19981578
• Balloon atrial septostomy Risk factor for death,
  not an ameliorating factor. Balloon dilatation of
  left vertical vein in obstructive supracardiac
  TAPVC may provide important clinical improvement
  and short term hemodinamic stability before
  operation
• Kiziltepe U et al. Acute pulm hypertensive crisis
  after TAPVC repairtreatment. Internat J of
  Cardio 200287107-109
• Treatment of recurrent severe pulm hypertension
  refractive to medical treatment can be dealt with
  inflow occlusion and creation of large intra
  atrial connection. Chest left open post
  operatively.

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Post operative PV stenosisStark J, De Leval MR.
Management of pulm venous obstruction after TAPVC
repair. Eur J Cardio-Thorac Surg. 20032428-36

• Complicates surgery in 5-10
• Classification of PV stenosis
• Discrete stenosis
• Tubular focal stenosis
• Diffuse hypoplasia
• May be severe anastomotic stenosis or pulmonary
  vein stenosis.

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Post operative PV stenosis

• Predominate after correction of Infracardiac and
  cardiac TAPVC.
• Vary from Fibrosis and neo-intimal proliferation
  at the anastomotic site, to segmental or diffuse
  intimal hyperplasia with extension to the
  individual pulm veins
• Abnormal architecture of pulm venous wall leads
  to increased tendency to neo intimal
  proliferation with increase in intimal and
  muscular media.
• Obstruction involving individual PV occurring
  early post op Very difficult to treat with high
  re-stenosis rate.
• Poor prognosis. 66 early mortality.

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Post operative PV stenosis

• Risk factors
• Use of Gore-tex patches
• Early presentation
• difficult anastomosis
• small pulmonary venous confluence
• Diagnosis
• Pulm venous flow patterns which does not reach
  baseline throughout the cardiac and resp cycles
• Absence of pulm venous return from one lung
• TR jet velocity gt 3m per sec.
• RV pressure gt40 mmHg
• Increase in pulm blood flowgt1.8 m per second
• Scrupulous and atraumatic technique still remain
  the best option for success. Use of absorbable
  sutures controversial.

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Post operative PV stenosis

• Repair
• 100 success rate achievable in anastomotic
  stenosis. Patch enlargement relieves stenosis and
  re stenosis is uncommon,
• No surgical approach including patch
  augmentation, longitudinal incision with
  transverse plication, balloon dilatation or
  placement of stents has shown any improvement in
  patient outcome.
• Goldenar syndrome (Infracardiac TAPVC, R lung
  hypoplasia, sub arterial VSD and ost secundum
  ASD) has a particular tendency to PV stenosis
  irrespective of type of repair. End with near
  atresia of PVs