Mavroudis - d-TGA

TGA Mav25

Divide into:

-TGA intact septum (50%)

-TGA + VSD (25%)

-TGA, VSD, PS (25%)

Assoc xx

-PDA, CoAo

Epi

#1 infant cyanotic heart disease

=9.9% of all CHD

Embryo/Anatomy

-?why:

-abNl separation of Ao & PA bc the septum was straight instead of spiraled

-abNl fibrous skeleton-w continuity bn MV & PA instead of MV & Ao

-abNl hemydynamics- obst to Q…

-inverted truncal swellings- inverted dvp of regions below semilunar vlvs

-Van Praagh: subAo conus persists & dvps during Nl D-looping, subPA conus undergoes absorption and then --> fibrous cont bn PA & MV ==> Ao is ant to PV, so that both semilunar vlvs align & connect w the distal GAs w/o undergoing a twist as usual

Assoc xx

-95% are Nl situs, Nl atria

-systemic vns usually Nl

-sometimes L or R atrial appendage juxtaposition

-ASD is mainly just PFO, but 2nd ASD seen in 10-20%

-R sided arch in 4% if intact IVS, 16% if +VSD

-+/- fxl obst of LVOT if no VSD bc IVS bulges to L side

-rare to have anatomic subvalvar stenosis if no VSD

-50% w VSD, many close spont'ly

-most are infundibular/perimembranous

-TGA-VSD assoc xx

-PS & Pulm atresia

-Overriding/straddling AV vlv

-CoAo

-InterrAo

-RVOTO is very rare

GA relationship - variable

-usually Ao R & Ant to PA

Cor Arts

-nearly always face the PA (good bc better for the switch)

-see below on cor arts

MV & TV

-usually fx fine if intact septum

-w VSD, TV abNly/stradd/overriding seen

-TV straddling is assoc w RV hypoplasia- xx for Tx…

Physiology

-2 parallel circulations

-Mixing needed for life

-if intact IVS, survive bc of Q thru PDA & bc of L-->R atrial shunt thru the PFO

-only marginal tissue oxygenation fr the mixing

-no change w incr FiO2…

-thus do a BAS to incr atrial mixing

-TGA w VSD

-allow for more mixing and more Qp

-but a small VSD--> minimal mixing…

-large VSD- incr Qp & mixing--> pink TGA w pulm overcirc.. r/o phtn eventually

-if Pulm outflow tract obst, --> risk of worse cyanosis

-rare if intact IVS

-usually bc of subvalvar stenosis, bc of septal deviation bc of RV distension, that usually resolves after arterial switch bc no longer have RV systemic P…

-more common w VSD

-usually milder cyanosis, tend to have Sx of TGA later than if intact IVS

-if PS Sx arise, need a cyst to PA shunt initially, followed by a repair (Rastelli or REV) (some may repair it at once)

-Pulm vasc dz

-may occur even w/o VSD, and w TGA+VSD, it occurs earlier than if pt had only a VSD

-?why, maybe bc differences in O2 sat, CO2 content, pulm art pH (ref 44)

Clinical Presentation

-cyanosis

-mildly overactie precordium

-if murmur- soft, systolic murmur, loud single S2

-Nl or bounding fem pulses (bounding if PDA)

-big liver if large syst-pulm shunt

-tachypnea/retractions if pulm overcirc

-ECG

-Nl

-CXR

-if VSD, maybe CM, incr pulm vascularity

-older infants w/o Tx- moderate CM w 'egg on its side' look

-maybe R sided plethora bc preferential RPA Q

-Echo

-Dx by echo…

-Cath- only if need BAS, or if need to check cor arts, VSD, degree of LVOTO, etc

Medical Tx

-BAS

-Ref 58- in one study, 20 of 1999 pts (9.9%) w isolated TGA died pre-op- fr small ASD/PFO

-PGE often given to incr Qp and improve mixing

Surgical Tx

Arterial Switch Operation for TGA with Intact IVS

-benefits over atrial switch- no assoc arrhythmia, baffle stenosis, TR, RV fail, or sudden death

-most common cause of death w ASO is cor art insufficiency

-most common post ASO xx is RVOTO (supra/sub vulvar) - Ref 83, 104-109

-0.5% per year risk of RVOTO - ref 107 multicenter study

-ref 110- maybe bc of size mismatch bn Ao vlv and PA trunk--> reactive infundib hypertrophy

-neo-Ao vlv xx is uncommon - ref 107

-ref 111-112- cor art obst Tx by prox cor arterioplasty and internal thoracic artery to cor art bypass

Technique

-Pericardial Harvest, dissection

-avoid phrenic n

-check cor art anatomy, plan for switch

-dissect out the GAs

-Cannulate and CPB

-cannulate at just prox to innom art and at bicava, or do single RA cannula

-hypothermia, maybe circ arrest during ASD closure and Ao reconstruction to free op field of the LV, vena cave cannulas etc; but avoid circa arrest >30min…;

-ref 128-129- deep hypothermia w circa arrest is better!

-ref 130-134- Boston Circ Arrest Study Group- low flow is better than circa arrest for neuro/devo outcome, better postop wt gain; no change in hops stay or ICU length, or mech vent duration. but circa arrest is assoc w higher sz risk and overall CNS xx vs low flow.

-ref 133- no change re IQ, but circa arrest had dec motor cordon and planning

-all pts regardless of circ arrest had below Nl IQ, expressive language, visual-motor integration, motor fx, oro-motor control

-Myocardial Protection

-Neoaortic reconstruction & transfer cor arts

-aortic cross clamp& cardioplegia

-transect the GAs

-excise cor arts w buttons fr the sinuses of Valsalva

-Lecompte maneuver- translocate PA (RPA) to be ant to asc Ao--> minimize PA tension

-punch excision sites for cor art implantation...

-Neopulmonary reconstruction

-goal: PA anast w/o future supra-vlv PS: pericardia patch augment the sinuses of Valsalva of the old Ao, prevent PA distortion by excessive dissection of both pulm hili, and ensure at least some direct continuity bn the branch PAs and the neo-PA vlv so it can grow in the future.

-need the patch to replace tissue fr cor arts w/o --> PS… some do double pericardial patch, others single, rec redundant patch w/o glutaraldehydeTx……

-Separate from bypass

Results

-ref 94-98 outcome studies

-ref 83- of 513 pts, 384 w intact VS, rest w VSD, all s/p ASO

-1mo survival 84%, 1yr 82%, 5yr 82%

-r/f for death = -origin of LCA or LAD or circa fr R post sinus, spec if intramural course

-multiple VSDs

-longer myocardial ischemic time

-longer total circa arrest time

-ref 86, 87, 94-97, 157- confirmed outcomes

-supravlv PS ore likely in early experience w ASO, now less common, esp since use of autologous pantaloon shaped pericardial patch to fill out the dissected sinuses of valsalva for neo-PA

-myocard ischemia bc of core insuffic is still #1 cause of period death, now decreasing since better myocard preservation and better cor art transfer

-Nl sinus rhythm in most pts postop >95%,

-neo-AR- seen in 5-10% pts, usually mild and non-progressive

-TGAw intact IVS- 6-13% op mortality at institutions w low risk

Arterial Switch Operation for TGA with VSD

-intially, ppl waited to up to 18 months even doing PAB in mean time, but then done as neonate…

-major limitation for surge is pt size

-some may do PA band w later repair if low birth weight

-Mavroudis reports 53 pts w TGA/VSD fr 1983-2003, mean 9mo and now moving twd early repair w/o PAB

-recently only ones w CoAo had initial PAB and CoAo repair w later full repair

-early survival 92%, w 3 late deaths--> "intermediate survival 94%"

-repair is as above, plus VSD repair

-bicaval cannulation so you can get max RA exposure, or do a transpulm or transAo repair

-rec VSD repair before art switch

-results

-ref 87- Quaegebeur et al- 18% op mortality in 1986, same as ref 83 congen hrt surg society- 6-13% mortality at 7 low risk institutions

-ref 162-163- safe to do art switch + VSD repair as neonate

-ref 164- overall mortality is 6.2%for ASO repair of TGA, regardless of whether pt had VSD

Staged Repair for TGA + Intact IVS

-if pt presents too late for ASO

-LV P dropped bc neonatal elevated PVR dropped… deconditioned

--> must first do PA band w a syst to pulm shunt, then an ASO...

-ref 72- Mavroudis recs for LV prep for later ASO

-LV ready for ASO if LV wall is thick for BSA, LVP >70% of RV P (systemic P), and Nl LV volume & muscle mass for age

-of 22 pts they repaired, xx p PAB = pacer need, thoracic empyema, resp arrest w resid neuro xx; xx p ASO = 1 death fr cor art xx, 3 late deaths fr pna and tracheostomy xx

-of the 2 pna pts, they had ventric fibroelastosis ?bc too long wait p PAB to do ASO (5mo and 15mo), so they do the ASO sooner after PAB.

-ref 93- 20 pts w staged repair reported in1980- 15% early death, …. p ASO 29% died

-said ASO safe if LV mass >60% of Nl, LVP >65mmHg or LV to RV P ratio>0.8

-ref 162- 7% surgical mortality w 2 stage repair of 91pts

-best Tx is <14 days old

-if pt is presented p 1 month old, rec prep LV w PAB and BTS

Arterial Switch Operation for DORV w Subpulmonary VSD (Taussig-Bing Anomaly)

-some do a baffle + conduit

-some do a baffle + ASO

-sometimes do Kawashima if side-side GA- posterior tunnle…

-sometimes need a DKS- close VSD, connect LV to PA, divide PA trunk at connect prox PA to Asc Ao via end to side anast, then a valved extracardiac conduit is placed fr RV to distal PA

…

…

ASO + baffle seems to be teh best …

Staged Arterial Switch for RV Failure after Atrial Baffle Procedures

-up to 10% of atrial baffle procedures will --> RV fail (ref 196)

-sev TR, and phtn (ref 197)

-Surgical options:

-TV replace --> Mavr has had bad experience 4/6 pts died, 1 got OHT

-staged conversion to ASO

-OHT

-staged conversion first done by Dr Mee (ref 198)

-PA Band for LVH, then do ASO

-ref 199 - 12 pts w failed atr switch--> 9 got ASO w senning/mustard takedown & atr septation

-2 postop deaths p PAB, 1 got OHT 3mo postop

-ref 200-203- ASO w/o PA band first- in pts w pulm vn obstruction (so LV didnt need retraining)

-ref 204- Mavr experience

-11 pts- PAB then ASO- 4 got OHT in the end for biventric failure, 6 got an ASO, 2 early deaths and no late deaths in those 6 that got ASO.

-w staged conversion, place PAB until PAP is 75% of Ao P or of RVP

Acquired Supravalvar PS

-long term xx of ASO:

-anastomosis site constriction

-neo-Ao regurg

-cor insufficiency

-reop- #1reason is for supravalvar PS

-ref 205, 206, 207, 87 note postop PS

-ref 87, 107, 205, 207- resid RV to PA gradient bc of anast site stenosis, ? bc of pericard patch constriction, or purse spring suture, anastomotic tension

-ref 75- may be more periph PA stenosis if inadequate dissection, ng anatomy p Lecompte

-ref 118, 206, 208- w more experience, acquired PA stenosis is low- 12% (ref 107), and no change w time

-pref single patch of pericardium - ref 71

-vessel config (GA relation) didn't effect xx or coronary transfer

-reop needed in 62/514pts for RVOTO (ref 83)

-infundib or vlvr obst was assoc w S/S GA relationship, +CoAo, prosthetic material used at neo-pulm sinus reconstruction

-risk adjusted incidence of reop for RVOTO = 0.5%/yr p ASO

-rec a single, large pantaloon pericard patch at sinus of valsalva of neo-pulm art

Neo-Aortic Insufficiency & Neo-Aortic Anastomosis Stenosis

-no signif supravlv AS (ref 114, 118, 207, 209)

-low incidence of neo AR & if present, doesnt progress- ref 64, 83, 210

-ref 83- only 6/514 pts (1%) had reop for LVOTO

-of 3 pts needing neo-Ao vlv replaced, they had PA band - ?if PAB--> old pulm vlv annular dil'n

Damus-Kaye-Stansel Procedure

-connect the proximal PA to the Ao (so cor arts are supplied by the LV-PA flow)

-place RV-PA conduit

-close VSD if present

-Ao vlv remains closed bc the LV/PA pressure is > RVP

-helpful for staged conversion from atrial baffle, bc adhesions might prevent ability to transfer cor arts

-also used by some for Taussig-Bing heart

-xx = Ao vlv may leak or clot & need to change conduit as pt grows

TGA +VSD + PS

-d/o PS severity and VSD size/location

-cyanosis seen earlier w worse PS/smaller VSD

-BAS +/- BTS initially to increase mixing

-if balanced, might be able to wait for a few months without palliation

-Rastelli Repair

-LV flow via baffle to Ao. then RV-PA conduit

-VSD should be large & doubly committed to avoid dvp of baffle induced subAS

-Might need to:

-enlarge VSD

-resect subAo muscle

-reattach TV pap muscle if obstructive

-thus most surgeons prefer to delay it until p 1yo, and do palliation until then if needed

-Mortality 10-29% (ref 214-216) for initial procedure

-ref 217, 218- continued risk of death at reop for conduit stenosis and LV dysfx

-REV Repair

-in attempt to reduce need to replace conduit, dvpd by Lecompte

-Reparation a L'etage ventriculaire-

-resect infundib to enlarge VSD

-intraventric baffle fr LV to Ao

-Ao transection to do a Lecompte

-direct PA to RV reconstruction with an anterior patch fr the RV to the PA

-Mortality 18% - ref219

-Long term xx- obligatory PR, but ref 220-222- less reop for conduit

-ref 223- REV in neonates

-ref 224-225- modified REV, minimize RVOTO 2y to compression of the anteriorly placed PAs fr the Lecompte- tubular segment of Ao homograft is used to connect the RV to PA, without doing a Lecompte

-Nikaidoh Repair

-for TGA+VSD with LVOTO

-mobilzie Ao root

-transect MPA

-LVOT opened, resect subPA stenosis

-position Ao (w cor arts) into PA site- only need to move it post'ly slightly

-close VSD w patch or suture

-can move a cor art to better position if needed

-reconstruct RVOT w pericardium and attached to MPA (note PA valve is lost)

-note RVOT is made of patch antly and of the ant wall of Ao postly.

-may place a prosthetic pulm vlv too

-…variations may improve outcome.. w removal of one cor art to allow to rotate it slightly…