DORV & DOLV Mav24

-considers lesion as DORV if both GA mainly are from RV

-DORV w subPA VSD = Taussig-Bing = subset, unless PA is >90% fr LV in which case it is TGA w VSD

Controversies:

-should it be defined by presences of Ao-M discontinuity (presence of subAo conus)?

-Lev --> may or may not have mitral continuity to Ao or PA, it's DORV if both GA are mainly fr RV

-really there is a transition from TOF to DORV/subAo VSD there's a gradual dvp of subAo conus; same w gradual transition from Taussig Bing w PA from RV thru TGA end of spectrum w PA from LV

-Must it have bilateral coni to be DORV?

-because original Taussig Bing heart did have bilat coni, and was promoted early on to help w radiological DDx bn DORV and TOF, however Howell found pts w def DORV- both GA entirely from RV, where only 38% had two complete coni--> thus don't need 2 coni to be DORV

Hx

-...

Embryology

-more controversy

-Nly, bulbus cordis has 3 parts: proximally dvps the trabec part of RV, then conus cordis dvps into RVOT and LVOT, & distal part, the truncus arteriosus, dvps into prox Ao & PA.

-paired, opposing ridges form in the conus cordis and in the trunc art, and spiral as they ascend the heart tube, and then fuse to make the conotruncal septum, but the truncus unwinds so that the conotruncal septum becomes straight and does not remain helical..., then the semilunar vlv dvps at the conotruncal jct and the part of the distal bulbus separates the posterior Ao vlv from the AV cushions. The entire truncus is still over the bulbar cavity (the future RV), but as the distal bulbus is absorbed, the Ao is drawn to the L, over the primitive LV to create Ao-mitral continuity (the conus below the bulbus was absorbed at the left aspect, bringing the Ao next to the MV). The primary bulboventric foramen becomes teh LVOT, and a secondary interventricular foramen is made bn Ao and RV, which is later covered w tissue that forms the interventric part of the membranous septum.

-w DORV, per Anderson, there is a prob w conal malrotation, differential conal absorption, and changes in position of the ant part of the muscular IVS, as w the entire TOF to TGA spectrum of xx

-w TOF- counterclockwise (when viewed from above) rotation --> ant displace the conal/infundib septum, due to abs of mid part of the bulboatrioventric ledge. --> Ao override the ant part of the musc IVS, large VSD, narrow infundib

-w DORV- more counterclockwise rotation, w lack of abs of mid bulbo-av ledge--> DORV and bc lack of abs of the ledge there is discontinuity bn Ao & MV. Amt of rotation -- GA relationship/DORV type

-w TGA w VSD- extreme counterclockwise rotation of conal septum, w a sagittal orientation of the ant part of the muscular IVS, and the middle part of bulbus is absorbed to --> PA-MV continuity

-some say that unlike TOF & DORV, TGA-VSD does not result from conal mal-dvp, but rather fr truncal maldvp.

Morphology

AV & VA Relationships

-Atrial & Ventric Situs- 86% of DORV have concordant AV connections, and 11% discordant

-GA relationships- 3 patterns of GA to each other

-most are Nly related, w Ao post and R

-Ao to R of PA, in side-side pattern (parallel to each other, without spiral)

-least common- Ao ant and to L of PA = L-malposed

VSD

-usually unrestrictive = VSD diam = or > Ao diameter

-10% of time, it is restrictive

-rare not to have a VSD; if so then see MV/LV hypoplasia, along w ASD

-13% of pts have multiple VSDs

-Location

-most are conoventricular- bn the ant and post limbs of the septal band

-may be at the inlet septum, muscular septum, or PM

-Relation to GAs

-subAo VSD- most common type, occur in 1/2 of pts

-separated fr Ao vlv by the distance of the subAo conus, which varies. If no conus then the L cusp of the Ao vlv or the base of the ant leaf of the MV forms the post-sup margin of the VSD

-when the Ao is to the R, the VSD is usually at the superior IVS, posterior to the infundib septum

-usually perimembranous- reach the annulus of the TV at its ant-septal commissure, w MV-TV continuity at the post-inf rim of the VSD

-sometimes the post margin of the VSD is seprated from the base of the TV by a rim of musc tissue, bc the ventriculoinfundib fold fused w the septal band

-73% of pts w subAo VSD had bilat coni, 23% w subPA conus alone

-most w no subAo VSD, have doubly committed vSDs

-DORV w L-malposed Ao (Ao L and ant)- VSD is usually subAo, w VSD more ant and sup than others, ...

-Doubly Committed VSD-

-occurs in 10% DORV, w contiguous PA and Ao bc no septum in bn...

-SubPA VSD = Taussig-Bing- 30% of pts in a surgical series, usually unrestrictive

-lie ant and sup beneath the PV, cradled in limbs of septal band; similar to a VSD w L-MGA...

-if no subPA conus, the PA will override the VSD

-bilat coni in 1/2 pts

-Noncommitted VSD = Remote VSD- in 10-20% pts, far removed

RVOTO

-most common w subAo or doubly committed VSDs, uncommon in Taussig Bing

-usually infundibular obst, but can be valvar, w PS....

-other mechs- DCRV fr muscle bn the inflow and outflow RV parts, straddling AV vlv tissue, accessory tissue tags, membr IVS aneurysm, but are assoc w pulm atresia

SubAo Stenosis

-uncommon but important

-most often in pts w subPA VSD, especially in Taussig-Bing hearts that have an arch obst

-also can be blocked by AV vlv tissue, tissue tags, hypertrophied muscle bundles, valvar AS or atresia

Conduction System

-His bundle penetrates the fibrous right trigone of the central fibrous bod, and lies at the post-inf margin of the VSD in lesions w a perimembranous extension. If there is muscle bn the defect and the TV, then the muscle protects teh bundle and so it does not run along the post-inf margin of the defect...

Coronary Art Anatomy

-RCA arises fr the R posterior facing sinus, and LA fr the left post facing sinus

-30% of pts had anomalies in one series

-LAD fr RCA, and run antly beneath the PV across the RVOT

Assoc Cardiac Anomalies

-AVCD

-AV vlv stenosis, atresia, straddling

-CoAo, Interr arch

-ventric hyoplasia

-unroofed CS

-abNl sys vn return

-juxtaposed atrial appendages

-dextrocardia

-ASD

Classification

-often by VSD type

-congen heart surg nomeclat and db project committee

-VSD type- subAo, doub comm w/o RVOTO

-TOF type- subAo, DC VSD w RVOTO

-TGA type- subPA VSD, T-B heart

-remote type- noncommitted, +/-RVOTO

Pathophys

-usually present at mean 2mo, range 0-4yrs

-Sx d/o PS presence

-CHF

-if no PS, like a large VSD...

-Cyanosis- fr streaming..., TGA like w T-B heart...

Dx

-...

NHx

-similar to that of a large VSD if no PS, or TOF if PS

Tx

-timing of surgery d/o pt Sx, usually done early as possible

Potential Problems:

-Biventric repair c/i xx if

-ventric hypoplasia

-serious AV vlv xx

-an AV vlv >2 Z scores smaller than the mean often used as criteria

-severe straddling/overriding of AV vlv cords

-very remote VSD/multiple VSDs

-irreversible pulm vasc dz

Surgical Repair- general approach

-cannulate Asc Ao, SVC, IVC

-hypothermia, low flow CPB, rarely circ arrest

-vent LV w sump across the atrial septum, in LA

-cardioplegia q20-30min

-assess anatomy thru TV; repair heart thru TV +/- RV ventriculotomy

-can use a transverse RV ventriculotomy if enough distance bn LAD and RCA & if you don't need a transannular patch, otherwise do a vertical RV ventriculotomy; avoid the large conal RV branches

DORV w SubAo or DCVSD without PS

-Timing: early infancy, to prevent pulm vasc dz

-young age per se is no longer a risk factor for hospital death- ref 4, 128, 129

-rarely,need a PA band, but not rec'd routinely

-Technique- Intraventricular Tunnel Repair

-compare VSD size to Ao, & enlarge the VSD if it is restrictive = smaller than Ao vlv diam, by incising it ant/suply or by resecting a wedge of IVS ant-suply, avoiding MV apparatus and ant LV wall w LAD

-resect obstructive RV muscle bundles

-may need to resect part of the infundibulum to put in a straight tunnel bn VSD & Ao

-If the distance bn the RV and PV is + or > diam to the Ao vlv then you can usually make the baffle without obstructing the PV outflow - measure by echo w subxyphoid view

-patch from the inf edge of the VSD, with sutures made away from the post-inf border to avoid the conduction tissue, to the superior edge of the Ao annulus. If there's a ledge of muscle at the post edge of the VSD (thus not a PM VSD, thus separating VSD fr TV... protecting conduction tissue), may suture into it...

-Complications-

-rare

-Complete HB- uncommon

-NYHA I in 87% pts

->90% pts (n=50pts overall) w only an intraventric tunnel repair for subAo or DCVSD, didnt need reop at f/u

-reop was for tunnel dehiscence, resid VSD, discrete subAS unrelated to the tunnel

-Results-

-current era- very low risk of death for subAO/DC VSD, 96% 15yr survival

-older age, not younger age, is now a r/f for death ? bc of pulm vasc dz

DORV with SubAo or DC VSD with PS

-Timing- similar to TOF, repair by 6mo if cor art anatomy is Nl and if intraventric repair can be performed

-c/s palliative syst to pulm art shunt if preop xx, or branch PAs are hypoplastic

-Surgical strategies

-avoid transannular patch if possible

-if needed for PA annular hypoplasia or pulm vlv stenosis--> use aggressive transatrial/transpulm endocardial resection of the hypertrophied obstructive muscle bundles --> need to incise less of the transannular region, avoiding RV dysfx later

-RV ventriculotomy if can't see RVOT thru TV

-if anom cor art at RVOT just beneath the pulm vlv annulus, or if signif pulm vasc dz, then need to place a valved extracardiac conduit if endocardial resection alone isn't enough to fix the RVOTO.

-if it is purely valvar, then do pulm valvotomy or valvectomy

-Results

-great fxl outcomes

-50% freedom from reop at 10yrs if you placed a heterograft valved conduit fr RV to PA, ? if homografts are more durable...

DORV w subPA VSD

-approaches proposed:

-1 patch tunnel VSD to PA + atrial switch (Mustard/Senning)

-2 tunnel VSD to PA, connect Ao and PA (DKS procedure), and place valved RV-PA conduit

-3 directly tunnel VSD to Ao

-4 tunnel VSD to PA and do an arterial switch

-5 tunnel VSD to Ao and translocate the PA (REV procedure- move the PA w the pulm vlv to the RV...)

1) Tunnel VSD to PA + Atrial Switch

-no need today

-43% (n=23 overall) who underwent this repair died in hospital in one series

-xx- rhythm xx, TR, outflow tract obstruction, reduced ventric fx w DOE, need to replace LV to PA conduits.

-Comparison- 5yr survival of TGA w VSD who had atrial switch was only 54%

2) DKS Procedure, Tunnel Closure of VSD & RV to PA Conduit

-tunnel VSD to the PA, connect PA to Ao, close Ao vlv, place a vlved extracardiac RV to PA conduit

-restores ventric-arrterial concordance w/o needing to relocate cor arts

-but --> need an extracardiac conduit

-no current applications for it given current abilities for art switch...

3) Total/Partial Intraventric Tunnel Repairs for Taussig-Bing Malformations

-can be done w a posterior, tubular conduit repair of Abe, or w an anterior, tubular conduit method of Doty, or w anterior, spiral tunnel repair by Patrick & McGoon, or w a posterior straight tunnel repair by Kawashima...

-Abe & Doty repairs- Abe for side/side GAs, Doty for A/P GAs

-but can't grow, tend to form pseudointima, and thus subAo stenosis --> no longer used

-Patrick-McGoon techniques- tunnel placed running to the L and anterior to the pulm vlv... no longer used, often must enlarge the VSD

-Kawashima operation- if GAs are side/side, can connect LV direct to Ao w tunnel going posterior to PA bn the TV and PA, but must resect the infundib septum

4) Arterial switch w tunnel closure of VSD

-successful for Taussig Bing w any GA relationship

--> major decr in T-B mortality, to 14% postop mortality in a series of 14 pts,

-2 pts had subvavlar muscle obst of pulm outflow, and one had a residual VSD

-another series of 27 pts had only 4% mortality, w a 9 year survival of 83% (+/-8%), but only a 46% (+/-20%) 9yr freedom from reop, due to RVOTO mainly

5) REV Procedure

-if the standard intraventric tunnel repair can't be done...

-e.g. there is PS so can't do an arterial switch

-but it will --> PR, so restrict to pts w PS and low PVR bc they tolerate it better than pts w unrestrictive Qp preop

-Technique

-inferior part of a verticle RV ventriculotomy is made, then carry sup'ly as close to Ao vlv as possible

-transect both GAs- Ao several mm above vlv, PA just above the vlv

-resect the infundib septum bn the two outflows

-if Ao post/R of PA, the infundib septum can be used as the ant wall of the tunnel

-if the GAs are ant-post, the infundib septum is usually bn the VSD and teh Ao, so must resect

-patch from post margin of VSD to ant part of the Ao vlv

-c/s Lecompte maneuver- not needed if side/side Ao or Ao slightly anterior

-reattach Ao to Ao vlv

-make a vertical incision in the MPA anteriorly and attach it to the sup part of the RV incision, and patch close the inferior part of the RV incision and ant part of the PA. Monocusp pericardial valve can be put in to limit PR.

-Results

-18% hospital mortality in series of 50 pts

-Indications/Timing

-?precise indications of REV for DORV, bc no long term f/u, but c/s it for DORV w low Qp for whoom a tunnel fr LV to Ao precludes the use of native pulmonary outflow tract (bc of PA-TV distance, PS, etc)

-Rastelli is less attractive because you'll need to replace the conduit in the future

-age- Lecompte has done it bn 4mo and 13mo but ? which is best, maybe 6-12mo..., can do it earlier if you are confident pt def won't need a Fontan like repair...

6) Nikaidoh Procedure

-Ao translocation and biventric outflow tract reconstruction, for DORV or TGA-VSD who can't get an art switch bc of pulm outflow obst (LVOTO)

-Technique

-mobilize Ao root along with cor arts

-transect MPA just above pulm vlv commissures; excise pulm vlv

-divide pulm root longitudinally, thru IVS and into lumen, and resect subpulm tissue

-translocate Ao root posteriorly to the former PA location..., suture to PA annulus

-close the VSD to reconstruct LVOT

-construct the RVOT by suturing a patch over the ventriculotomy and extend it over the anterior Ao root, and suturing the patch to the distal end of the transected MPA trunk...

-Results

-of 14 pts 2-7yo, 1 operative death fr myocardial ischemia, 3 reops for obstructed RV-PA conduit, pericardial RVOT patch, and for RV dysfx fr PR

-potential advantage over REV_ more straight and direct LV to Ao connection

-has only been used to date for TGA-VS w pulm stenosis, but could be used for DORV w subPA VSD and ant-post GAs, but it is not recommended in general bc more complex than REV w/o much advantage...

DORV w Noncommitted VSD

-Two ventricle Repair of DORV/Remote VSD

-often an inlet VSD, some can get a tunnel repair; may need to enlarge the VSD sup/ant to do it

-if the tunnel obstructs RVOT, may need a transannular patch or valved extracardiac conduit

-Single Ventricle REpair of DORV/Remote VSD

-if TV app is in the way, or VSD is in trabecular septum, or multiple VSDs; and if assoc PS, then c/s syst-PA shunt followed by Glenn/Fontan pathway

-if no assoc PS, then PA Band as neonate to protect pulm vasc bed

-in one group of 9 pts, 2 =9% died in hospital after biventric repair

-high reoperation rate- 35%

Complex DORV w Straddling AV Valves

-some do Fontan, others try a biventric repair...

Late Sudden Death in Survivors of DORV Repair-18% incidence of late sudden death in 89 survivors of DORV repair

-older age at operation, perip or post op VT, and 3rd degree HB were r/f for late sudden death

DOUBLE OUTLET LEFT VENTRICLE