Surgical Treatment of PA with VSD without/with MAPCA

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Surgical Treatment of PA with VSD without/with
MAPCA

• Jeong-Jun Park
• University of Ulsan, Asan Medical Center

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Pulmonary Atresia with VSD without/with MAPCA

• 1. Extreme subgroup of Tetralogy of Fallot
• 2. Major clinical problems in the arteries
  that
• supply the pulmonary circulation
• 3. Variable clinical presentations different
• surgical strategies to that in TOF/PS

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Morphology of PA with VSD

• The general morphology of the heart in TOF/PA
• - Similar to that in simple TOF,
  
• - The differentiating features are
• 1. No luminal continuity between RV PA
• 2. Pulmonary arterial anomalies
• 3. Aortopulmonary collaterals

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Natural History

• Variable depending on the pulmonary blood flow
• - At birth, ductus dependent in case of
  true PAs
• - After ductal closure, dependent on the
  collaterals
• 1) Excessive pulmonary blood flow CHF,
  PVOD
• 2) Moderate collateral stenosis
• Balanced pulmonary blood flow
• 3) Severe collateral stenosis hypoxia

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Patterns of Pulmonary Arteries

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Morphology of Pulmonary Artery

• 1. Confluence of the pulmonary artery
  
• 2. Stenosis of the pulmonary artery
• 3. Distribution of the pulmonary artery
  
• 4. Size of the pulmonary artery
• 5. Abnormal hilar branching

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Alternative Sources of PBF

• 1. MAPCAs
• 2. Paramediastinal collateral arteries
• 3. Bronchial collateral arteries
• 4. Intercostal collateral arteries
• 5. Collaterals from coronary arteries
• 6. Iatrogenically aggravated collaterals

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Origin of MAPCA

• MAPCAs
• - Variable in size, number, course, origin,
  arborization histologic makeup
• - Usually large discrete arteries from 1 to 7
  in number
• 1. Majority from descending thoracic aorta
• 2. Some cases, from a common aortic trunk
• 3. Finally, from branches of aorta

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Influence of MAPCA

• 1. Chronic shunt LV volume overload
• . Decrease LV function
• . Aortic annular dilatation
• . Aortic insufficiency
• 2. Segmental loss of lung parenchyme
• . In case of collateral stenosis --hypoxia
• . In unobstructed cases CHF, PVOD

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Histologic Characteristics of MAPCAs

• 1. Extrapulmonary muscular artery with well
  developed muscular media adventitia
• 2. Intrapulmonarymedial muscle is gradually
  replaced by a thin elastic lamina resembling
  true Pas
• 3. Unobstructed MAPCAs PVOD
• 4. Muscular segments of collateralsprone to the
  development of severe stenoses, often progressive

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Characteristic Features of MAPCAs

• 1. Variable in size, number, course, origin,
  arborization and histologic makeup
• 2. Various degree of PA hypoplasia , or even
  absence of the central PAs
• 3. MAPCAs connect with branches of central PAs,
  or constitute the only blood supply
• 4. Congenital or acquired discrete stenosis
  along the course of MAPCAs
• 5. PHT and progressive PVOD

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• Confluent PA

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• Unobstructed MAPCA

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• Long stenotic segment

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MAPCA Dilated Bronchial Arteries

• - RCH, 2006
• - All MAPCAs anatomy similar to bronchial
  arteries
• - BAs limited growth potential and
  vasoreactivity
• ? might preclude long-term beneficial effects
  
• of unifocalization

• Bronchopulmonary shunts

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Definitive Repair of PA with VSD

• Ultimate goal
• Completely separated pulmonary systemic
  circulation
• 1. Closure of ventricular septal defect
• 2. Establish continuity between RV PA
• 3. Occlusion of redundant collaterals shunts
  / Unifocalization

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Preparation for Definitive Repair

• 1. Maximize the pulmonary artery
• The size distribution
• 2. Maintain the adequate PBF
• 3. Avoid the excessive PBF

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Suggested Surgical Strategy for
PA with VSD, MAPCA

• 1. Unifocalization
• - Staged vs one-stage
• - Thoracotomy vs sternotomy
• 2. Establishment of native PA growth
• - With vs without unifocalization
• 3. One-stage complete repair
• 4. Repair without unifocalization

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Early Palliative Procedures

• Goals 1) Create a balanced PBF
• 2) Incorporation growth of
  PAs

- Systemic-pulmonary shunt - RV-PA connection
conduit or outflow patch - Unifocalization
- Ligation - Embolization - Creating stenosis
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Ideal Unifocalization Procedure

• Incorporation of all the nonredundant
  collaterals true Pas
• ? healthy microvasculature of lung
• 2. Use conduit that is growing, large,
  minimizing the risk of thrombosis
• 3. Easily accessible from the mediastinum
  at the time of definitive repair

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Timing of Unifocalization

• 1. At any age, when collaterals are large to
  allow technical ease without risk of
  thrombosis
• 2. Variable depending on collateral size,
  usually older than 23 months
• 3. Staged procedures may be required for the
  bilateral aortopulmonary collaterals

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Techniques of Unifocalization

• Procedures for collaterals
• 1) Ligation
• 2) Patch enlargement
• 3) Direct anastomosis
• 2. Interposition grafts
• 1) Synthetic graft
• 2) Homograft
• 3) Xenograft
• 4) Autologous tissue pericardium, azygos v.

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Unifocalization Procedures

• Ligation

• Angioplasty

• Anastomosis

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Unifocalization Procedures

• Interposition

• Additional PA
• creation

• Central PA
• creation

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Surgical technique of unifocalization

• - Offbypass during dissection
• - Maximal use of native tissue
• - Avoid circumferential use of non-viable
  conduits
• for growth potential

• End-to side

• Side -to side

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Surgical technique of unifocalization

• Aortic button several MAPCAs from the same
  location

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Surgical technique of unifocalization
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RV-PA Conduit
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Advantages of RV - PA Connection

• 1. Reduction of LV volume overload
• 2. Pulsatile blood flow to enhance PA growth
• 3. Facilitating the catheter access for the
  later evaluation intervention
• CIx d/t
• 1) aneurysm and pseudoaneurysm
• 2) pulmonary flow and pressure is completely
  uncontrolled

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Melbourne Shunt

• Central end-to-side Aortopulmonary shunt
• Diminutive central pulmonary arteries

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Modified Central Shunt
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Criteria for VSD closure 2 Dimensional Anatomic
Data

• - Central PA area ? 50 of predicted normal
• -
  by Puga, 1989
• - Predicted pRV/pLV ? 0.7, No MAPCAs remain
• More than 2/3 lung segments are centralized
• -
  by Iyer and Mee, 1991
• - Nakata Index gt 150mm2/M2 BSA -by Metras,
  2001
• - TNPAI ? 200 mm2/m2 - by Hanley,
  1997
• - 15 out of 20 bronchopulmonary segments(1
  1/2 lungs) are connected to confluent pulmonary
  artery
• -
  by Baker, 2002

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Functional Intraoperative Pulmoanry Blood Flow
Study

• Post-repair RVSP most reliable predictor of
  favorable outcome
• Data of functionality of the entire pul.
  vasculature
• Hanley
• - m PAP lt 25mmHg at a full flow(2.5L/min/m2)
• predicts RV/LV pressure ratio lt 0.5
• Toronto, 2009
• Close the VSD for a mPAP of lt30mmHg
• Predict postop. Physiology better than standard
  anatomic measures

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Functional Intraoperative PBF Study
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Repair without Unifocalization

• - RCH, 2009
• - Unifocalization brings no long-term benefits
• . Unifocalization sufficient to allow a safe
  repair
• but, failed to achieve adequate
  growth
• . Dilated BAs limited growth potential
  unstable
• Growth of the native PA rather than recruitment
  of MAPCAs
• - Multi-stage approach
• . 46wks Modified central shunt
• . 46months RV-PA conduit
• . 3rd complete repair or 2nd conduit
• 18 pts enrolled in this protocol (No
  Unifocalization)
• . 7 complete repair, RVP 59 of systemic
• . 8 awaiting repair
• . 4 MAPCAs in 17 pts ligated

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Advantages of One-stage Complete Repair

• 1. Eliminate the need for multiple operations
• 2. Eliminate the use of prosthetic materials
• 3. Establish the normal physiology early in life
• 1) Growth of respiratory PA system
• 2) Avoid cyanosis volume overload
• 3) Prevent the PVOD

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Disadvantages of Multistage Approach

• 1. The final repair is achieved on an old age
• 2. Mediastinum hilar regions are significantly
  
• scarred, increasing surgical risks
• 3. Prolonged cyanosis previous operation cause
• secondary collaterals, risks of bleeding
• 4. The risk of drop-off before the final repair

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Disadvantages of Earlier Repair

• 1. Increased pulmonary morbidity
• 1) Contusion congestion
• 2) Bronchospasm
• 3) Phrenic nerve injury
• 2. Magnitude of operation
• 3. Technically more demanding
• 4. Unknown ideal age

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Conclusion
- MAPCAs Wide spectrum of pul. vascualr
morphology and physiology, Ranging 1) from pts
on the favorable end true PAs with
collaterals simply contributing systemic
flow into the pul. vasculature 2) to pts on
the unfavorable end with completely
absent native PAs and all of the pulmonary
blood supply from collaterals ? Management
complex and must be individualized
according to their anatomy and clinical situations
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Predictors of Successful Definitive Repair

• 1. McGoon Ratio gt 1
• 2. Nakata Index gt 150mm2/M2 BSA(Metras, 2001)
  ????
• 3. TNPAI gt 200mm2/M2 BSA
• 4. Ideal Age
• Not known , but usually more than 2-3years
• old for conduit repair
• 5. 15 out of 20 bronchopulmonary segments(1 1/2
  lungs) are connected to confluent pulmonary
  artery Baker EJ. 2002

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Selection for Final Repair

• 1. Central combined Rt. Lt. PA area
• At least 5075 of predicted normal
• 2. Distribution of unobstructed confluent PAs
  
• Equivalent to at least one whole lung
• 3. Presence of a predominant Lt. to Rt. shunt
• without restrictive RV-PA connection

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Representative Data
Approach Age(range) VSD closure Mortality (early)
Mee RBB (91) Multiple 2.6mo (1d 39yr) 52(30/55) 10
Hanley FL (95) Anterior 2yr (2mo 37yr) 90(9/10) -
Hanley FL (97) Anterior 4mo (10d 11mo) 63(17/27) 7
Hanley FL (98) Anterior 7.3mo (14d 37yr) 64(46/72) 11
Lofland GK (00) Anterior 3mo (5d 5.5mo) 91(10/11) 9.1
Cherian KM (02) Anterior 36mo (6mo 23yr) 51(26/51) 16
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Midline One-stage Unifocalization
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Staged Unifocalization
RV-PA Connection
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One-stage Unifocalization
RV-PA Connection
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RVOT Reconstruction with Valved Conduit
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RVOT Reconstruction with Outflow Patch
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RVOT Reconstruction with PA Reimplantation
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RVOT Reconstruction with LA Appendage
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RVOT Reconstruction with PA Flap
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RV-PA Connection Unifocalization
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RV-PA Connection with Unifocalization
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Midline One-stage Repair
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Midline One-stage Repair
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Staged Unifocalization

• M / 20 Mo, 10.6 kg Postop. 7 Mo

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One-stage Unifocalization

• M / 46 Mo, 13 kg Post-op. 8 Mo

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RV-PA Connection

• F / 3 Mo, 4.6 kg Post-op. 3 Mo

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RV-PA Connection with Unifocalization

• F / 15 Mo, 7.5kg Post-op. 11 Mo

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One-stage Total Correction

• M / 7 Mo, 6.4kg Post-op. 1 Mo

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Surgical Results of PA
with VSD,MAPCAs
- Anterior approach -

• Yang Gie Ryu, Jeong-Jun Park,
• Tae Jin Yoon, Dong Man Seo

Dept. of Thoracic and Cardiovascular Surgery AMC,
University of Ulsan
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Representative Data
Approach Age(range) VSD closure Mortality (early)
Mee RBB (91) Multiple 2.6mo (1d 39yr) 52(30/55) 10
Hanley FL (95) Anterior 2yr (2mo 37yr) 90(9/10) -
Hanley FL (97) Anterior 4mo (10d 11mo) 63(17/27) 7
Hanley FL (98) Anterior 7.3mo (14d 37yr) 64(46/72) 11
Lofland GK (00) Anterior 3mo (5d 5.5mo) 91(10/11) 9.1
Cherian KM (02) Anterior 36mo (6mo 23yr) 51(26/51) 16
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Criteria for VSD closure

• - Central PA area ? 50 of predicted normal
• 
  (by Puga, 1989)
• - Predicted pRV/pLV ? 0.7
• No MAPCAs remain
• More than 2/3 lung segments are centralized
• 
  (by Iyer and Mee, 1991)
• - TNPAI ? 200 mm2/m2 (by
  Hanley, 1997)
• - ? Unprotected large MAPCA

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Patient Profile

• Period Jan. 1997
  Jul. 2002
• Number 25 (M F 12 13)
• Age(mo), median 8 (3 190)
• Weight(kg), median 6.8 (2.9 62)
• Follow-up(mo), median 16 (3 150)

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PA,VSD,MAPCAs (n25)
VSD closed (n19,76)
VSD open (n6,24)
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Demographic Data
Group Ia (VSD closed) Group Ib (VSD closed) Group II ( VSD open )
No. of pts() 11(44) 8(32) 6(24)
Age(mo) Median Range 8 3 11 10.5 4 190 10.5 5 58
Weight(kg) Median Range 6.7 2.9 8.1 8.05 5 62 7.9 5.1 15.8
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MAPCAs True PAs
Group Ia (VSD closed) Group Ib (VSD closed) Group II (VSD open)
No. of MAPCAs Mean Range 3.6 ? 1.2 1 5 3.3 ? 1.3 1 5 3.6 ? 0.5 3 4
True PAs Present Absent 7 4 7 1 6 0
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Operation
Group Ia (VSD closed) Group Ib (VSD closed) Group II (VSD open) Total
Surgical approach Median sternotomy Sternotomy thoracotomy 7 4 6 2 4 2 17 8
RV-PA conduit Homograft Pericardial roll Transannular patch 8 2 1 5 1 2 3 1 1 16 4 4
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Detail of Group Ia (n11)
Pt Confluency of PA Neo-McGoon ratio No. of MAPCAs Age
1 - lt 2.0 5 4m
2 Hypoplastic gt 2.0 4 8m
3 Hypoplastic gt 2.0 4 6m
4 - gt 2.0 4 12m
5 Good gt 2.0 3 6m
6 Hypoplastic lt 2.0 5 10m
7 Good gt 2.0 5 8m
8 Good gt 2.0 1 4m
9 Good lt 2.0 3 4m
10 - gt 2.0 3 8m
11 - gt 2.0 3 9m
Neo-McGoon ratio (True PA each MAPCA) /
descending aorta
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Detail of Group Ib (n8)
Pt Confluency of PA Neo-McGoon ratio No. of MAPCA 1st Op (Age) 2nd Op (Age)
1 Hypoplastic lt 1.5 3 RV-PA conduit 11m Total 16m
2 Hypoplastic lt 2.0 3 Lt.unif 8m Rt.unif 22m
3 - gt 2.0 5 Rt.unif 13m Total 6y 6m
4 Hypoplastic gt 2.0 4 RVOT relieve 5m Total 10m
5 Hypoplastic gt 2.0 4 RVOT relieve,unif 8m Total 18m
6 Hypoplastic AP window gt 2.0 1 RV-PA conduit,unif 9m Total 10m
7 Hypoplastic gt 2.0 3 RV-PA conduit,unif 16m Total 3y 1m
8 gt 2.0 1 RV-PA conduit,unif 15y 10m Total 24y 1m
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Detail of Group II (n6)
Pt Confluency of PA Neo-McGoon ratio No. of MAPCAs Op name (Age) Outcome
1 Hypoplastic lt 2.0 3 Bilat.unif,Central shunt,RV-PA conduit Cath F/U
2 Hypoplastic lt 2.0 4 RV-PA conduit 6m Poor growth of PA-gtdeath
3 Hypoplastic gt 2.0 4 RV-PA continuity 10m Waiting
4 Hypoplastic lt 1.0 4 RV-PA conduit,unif 3y 2m Waiting
5 - lt 1.5 3 Bilat.unif 6m Observ.
6 Hypoplastic gt 2.0 1 RMBT,cetral shunt RV-PA conduit(9m) Death
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Cases of Mortality (n6)
Gr Age Anatomy Cause of death
Ia 4m PA,VSD, 5 MAPCA Respiratory failure Bronchial stenosis
Ia 6m PA, VSD, 4 MAPCA Pulmonary Hemorrhage
Ia 6m PA,VSD, 4 MAPCA Pulm. Hypertensive crisis
Ia 12m PA,VSD, 4 MAPCA Bronchus compression
II 6m PA,VSD, 4 MAPCA Poor growth of PAs
II 4y 11m PA, VSD, 1 MAPCA PVOD
Pulmonary hypertension related
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Results

• Total correction 76
  (19/25)
• One stage total correction 44 (11/25)
• Early mortality 16 (4/25)
• Late mortality 9
  (2/21)

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Conclusion

• Anterior approach? ??? ???? ??
• ? ?? ????(gt80).
• Too small or unprotected large MAPCA?
• recruit?? ???? ??? ??? ???
• ????.
• PVR? ?? ??? ???? ??? staged
• op.? reasonable ???.

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Conclusion
Just now we are ready to manage this group of
patients properly in technique and hemodynamic
understanding.