Surgical Treatment of PA with VSD without/with MAPCA Jeong-Jun Park University of Ulsan, Asan Medical Center

Pulmonary Atresia with VSD without/with MAPCA Extreme subgroup of Tetralogy of Fallot 1. Extreme subgroup of Tetralogy of Fallot 2. Major clinical problems in the arteries that 2. Major clinical problems in the arteries that supply the pulmonary circulation supply the pulmonary circulation 3. Variable clinical presentations & different 3. Variable clinical presentations & different surgical strategies to that in TOF/PS surgical strategies to that in TOF/PS

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

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

Patterns of Pulmonary Arteries

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

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

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

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

Histologic Characteristics of MAPCAs 1. Extrapulmonary: muscular artery with well developed muscular media & adventitia 2. Intrapulmonary:medial muscle is gradually replaced by a thin elastic lamina resembling true Pas 3. Unobstructed MAPCAs: PVOD 4. Muscular segments of collaterals:prone to the development of severe stenoses, often progressive

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

* Confluent PA

Unobstructed MAPCA

Long stenotic segment

MAPCA = Dilated Bronchial Arteries - RCH, All MAPCAs : anatomy similar to bronchial arteries - BAs: limited growth potential and vasoreactivity  might preclude long-term beneficial effects of unifocalization Bronchopulmonary shunts

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

Preparation for Definitive Repair 1. Maximize the pulmonary artery : The size & distribution 2. Maintain the adequate PBF 3. Avoid the excessive PBF

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

Early Palliative Procedures Goals 1) Create a balanced PBF 2) Incorporation & growth of PAs - Ligation - Embolization - Creating stenosis - Systemic-pulmonary shunt - RV-PA connection : conduit or outflow patch - Unifocalization Excessive blood flow Inadequate blood flow

Ideal Unifocalization Procedure 1.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

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 2~3 months 3. Staged procedures may be required for the bilateral aortopulmonary collaterals

Techniques of Unifocalization 1.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.

Ligation Angioplasty Anastomosis Unifocalization Procedures

Interposition Additional PA creation Central PA creation Unifocalization Procedures

End-to side Side -to side - Offbypass during dissection - Maximal use of native tissue - Avoid circumferential use of non-viable conduits for growth potential Surgical technique of unifocalization

Aortic button : several MAPCAs from the same location Surgical technique of unifocalization

RV-PA Conduit

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

Melbourne Shunt Central end-to-side Aortopulmonary shunt Diminutive central pulmonary arteries

Modified Central Shunt

Criteria for VSD closure : 2 Dimensional Anatomic Data - Central PA area  50% of predicted normal - by Puga, Predicted pRV/pLV  0.7, No MAPCAs remain More than 2/3 lung segments are centralized - by Iyer and Mee, Nakata Index > 150mm2/M2 BSA -by Metras, TNPAI  200 mm 2 /m 2 - by Hanley, out of 20 bronchopulmonary segments(1 & 1/2 lungs) are connected to confluent pulmonary artery - by Baker, 2002

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 < 25mmHg at a full flow(2.5L/min/m 2 ) predicts RV/LV pressure ratio < 0.5 Toronto, Close the VSD for a mPAP of <30mmHg -Predict postop. Physiology better than standard anatomic measures

Functional Intraoperative PBF Study

- RCH, 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. 4~6wks: Modified central shunt. 4~6months: RV-PA conduit. 3 rd : complete repair or 2 nd 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 Repair without Unifocalization

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

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

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

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

Predictors of Successful Definitive Repair 1. McGoon Ratio > 1 2. Nakata Index > 150mm 2 /M 2 BSA(Metras, 2001) 추가하자 3. TNPAI > 200mm 2 /M 2 BSA 4. Ideal Age : Not known, but usually more than 2- 3years old for conduit repair out of 20 bronchopulmonary segments(1 & 1/2 lungs) are connected to confluent pulmonary artery: Baker EJ. 2002

Selection for Final Repair 1. Central combined Rt. & Lt. PA area : At least 50~75% 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

Representative Data ApproachAge(range)VSD closure Mortality (early) Mee RBB (’91) Multiple2.6mo (1d ~ 39yr) 52%(30/5 5) 10% Hanley FL (’95) Anterior2yr (2mo ~ 37yr) 90%(9/10)- Hanley FL (’97) Anterior4mo (10d ~ 11mo) 63%(17/2 7) 7% Hanley FL (’98) Anterior7.3mo (14d ~ 37yr) 64%(46/7 2) 11% Lofland GK (’00) Anterior3mo (5d ~ 5.5mo) 91%(10/1 1) 9.1% Cherian KM (’02) Anterior36mo (6mo ~ 23yr) 51%(26/5 1) 16%

Midline One-stage Unifocalization

Staged Unifocalization & RV-PA Connection

One-stage Unifocalization & RV-PA Connection

RVOT Reconstruction with Valved Conduit

RVOT Reconstruction with Outflow Patch

RVOT Reconstruction with PA Reimplantation

RVOT Reconstruction with LA Appendage

RVOT Reconstruction with PA Flap

RV-PA Connection & Unifocalization

RV-PA Connection with Unifocalization

Midline One-stage Repair

Staged Unifocalization M / 20 Mo, 10.6 kg Postop. 7 Mo

One-stage Unifocalization M / 46 Mo, 13 kg Post-op. 8 Mo

RV-PA Connection F / 3 Mo, 4.6 kg Post-op. 3 Mo

RV-PA Connection with Unifocalization F / 15 Mo, 7.5kg Post-op. 11 Mo

One-stage Total Correction M / 7 Mo, 6.4kg Post-op. 1 Mo

Surgical Results of PA with VSD,MAPCAs Yang Gie Ryu, Jeong-Jun Park, Tae Jin Yoon, Dong Man Seo Dept. of Thoracic and Cardiovascular Surgery AMC, University of Ulsan - Anterior approach -

Representative Data ApproachAge(range)VSD closure Mortality (early) Mee RBB (’91) Multiple2.6mo (1d ~ 39yr) 52%(30/5 5) 10% Hanley FL (’95) Anterior2yr (2mo ~ 37yr) 90%(9/10)- Hanley FL (’97) Anterior4mo (10d ~ 11mo) 63%(17/2 7) 7% Hanley FL (’98) Anterior7.3mo (14d ~ 37yr) 64%(46/7 2) 11% Lofland GK (’00) Anterior3mo (5d ~ 5.5mo) 91%(10/1 1) 9.1% Cherian KM (’02) Anterior36mo (6mo ~ 23yr) 51%(26/5 1) 16%

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 mm 2 /m 2 (by Hanley, 1997) - ? Unprotected large MAPCA

Patient Profile Period Jan ~ Jul 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)

PA,VSD,MAPCAs (n=25) Gr Ia One stage total (n=11) Gr Ib Staged total (n=8) Group II (n=6) VSD closed (n=19,76%) VSD open (n=6,24%)

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 ~ ~ ~ 58 Weight(kg) Median Range ~ ~ ~ 15.8 Demographic Data

MAPCAs & True PAs Group Ia (VSD closed) Group Ib (VSD closed) Group II (VSD open) No. of MAPCAs Mean Range 3.6  ~  ~  ~ 4 True PAs Present Absent

Operation Group Ia (VSD closed) Group Ib (VSD closed) Group II (VSD open) Total Surgical approach Median sternotomy Sternotomy + thoracotomy RV-PA conduit Homograft Pericardial roll Transannular patch

Detail of Group Ia (n=11) PtConfluency of PA Neo-McGoon ratio No. of MAPCAs Age 1 -< 2.054m 2 + Hypoplastic > 2.048m 3 + Hypoplastic > 2.046m 4 -> m 5 + Good> 2.036m 6 + Hypoplastic < m 7 + Good> 2.058m 8 + Good> 2.014m 9 + Good< 2.034m 10 -> 2.038m 11 -> 2.039m # Neo-McGoon ratio = (True PA + each MAPCA) / descending aorta

Detail of Group Ib (n=8) PtConfluency of PA Neo- McGoon ratio No. of MAPCA 1 st Op (Age) 2 nd Op (Age) 1 + Hypoplastic < 1.53RV-PA conduit 11m Total 16m 2 + Hypoplastic < 2.03Lt.unif 8m Rt.unif 22m 3 -> 2.05Rt.unif 13m Total 6y 6m 4 + Hypoplastic > 2.04RVOT relieve 5m Total 10m 5 + Hypoplastic > 2.04RVOT relieve,unif 8m Total 18m 6 + Hypoplastic AP window > 2.01RV-PA conduit,unif 9m Total 10m 7 + Hypoplastic > 2.03RV-PA conduit,unif 16m Total 3y 1m 8 +> 2.01RV-PA conduit,unif 15y 10m Total 24y 1m

Detail of Group II (n=6) Pt Confluency of PA Neo- McGoon ratio No. of MAPCA s Op name (Age) Outcome 1 + Hypoplastic < 2.03Bilat.unif,Central shunt,RV-PA conduit Cath F/U 2 + Hypoplastic < 2.04RV-PA conduit 6m Poor growth of PA- >death 3 + Hypoplastic > 2.04RV-PA continuity 10m Waiting 4 + Hypoplastic < 1.04RV-PA conduit,unif 3y 2m Waiting 5 -< 1.53Bilat.unif 6m Observ. 6 + Hypoplastic > 2.01RMBT,cetral shunt RV-PA conduit(9m) Death

GrAgeAnatomy Cause of death Ia4mPA,VSD, 5 MAPCARespiratory failure Bronchial stenosis Ia6mPA, VSD, 4 MAPCAPulmonary Hemorrhage * Ia6mPA,VSD, 4 MAPCAPulm. Hypertensive crisis * Ia12mPA,VSD, 4 MAPCABronchus compression II6mPA,VSD, 4 MAPCAPoor growth of PAs II4y 11m PA, VSD, 1 MAPCAPVOD * Cases of Mortality (n=6) * Pulmonary hypertension related

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

Conclusion Anterior approach 는 수술의 완성도를 높 일 수 있는 술식이다 (>80%). Too small or unprotected large MAPCA 를 recruit 하기 위해서는 적절한 시기에 수술 이 필요하다. PVR 이 높을 것으로 의심되는 경우는 staged op. 이 reasonable 하겠다.

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