DORV & DOLV Lai25

DOUBLE OUTLET RIGHT VENTRICLE

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Morphology & Classification

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Anatomy

[ ] VSD location & size

[ ] membranous extension? (conduction system...)

[ ] AV vlv attachments to VSD margins

[ ] VSD relation to GA vlvs

[ ] conal morphology

[ ] spatial relationship of GA to each other

[ ] relationship of TV to PA (per Mavroudis and Jonas chapters)

[ ] associated xx

-outflow obstruction

-AV vlv anomalies

-ventric hypoplasia

-cor art anomalies

VSD Location & Size

-subAo

-subPA

-doubly committed

-Noncommitted

-usually is bn the antero-sup and postero-inf limbs of septal band

-spatial relation of VSD to GA vlvs is determined by presence/size/position of subAo conus & by deficiency of adjacent septal segments- the conal septum, the AV canal septum

-VSD size, distance bn VSD and semilunar vlvs, presence of AV vlv attachments along VSD margins are important for sugical repair

-SubAo VSD = 42-57% of DORV

-VSD is bn septal band limbs, below Ao vlv; post and to R of conal septum (thus conal septum directs Q into Ao and not into RV; and directs RV Q to PA, blocking RV Q from going to Ao)

-Post-Inf margin of VSD - +/- fibrous continuity w TV (if perimembranous extension), or may have a muscular extension of post limb of septal band (matters bc of conduction system...)

-if there is muscular extension of post limb of septal band = malalignment VSD aka conoventric septal defect

-if d-MGA (Ao Ant/R) , the conal septum is rotated out of plane w the IVS (is in sagittal plane), and attaches to the antero-sup limb of septal band. Often RVOTO, d/o amt of anterior and left deviation of conal septum and by assoc PV stenosis.

-if L-MGA, Ao is L of PA, then the subAo VSD is more anterior and superior within the septal band limbs --> Ao vlv or subAo conus is the sup margin of the VSD.

Subpulmonary VSD = 24-37% cases

-VSD is bn the limbs of septal band, but the conal septum is rotated out of plane with IVS, so it attaches to the more posteriorly located ventric infundib fold instead of to the ant-sup limb of septal band (so now the conal wall is behind the VSD, so VSD Q goes to PA)

-60% pts- the post-inf margin of the VSD is in continuity w the AV vlvs (membranous extension)

-40% pts- muscular inf border = continuity bn the RV infundib fold and the post-inf limb of the septal band

-subAo conus- usually well dvpd, Ao vlv is to the R of the PA vlv w side-side or slightly ant position

-subPA conus- size varies, may be incomplete, so that there's fibrous continuity bn PV and MV

-DDx DORV & TGA- by PV alignment to the ventricles- if PV is nearly entirely fr RV then DORV, if PV nearly all fr LV then TGA; for things in bn it d/o the MD reading the study!!

-many c/s DORV w subPA VSD to = Taussig Bing, actually the original T-B was a DORV w subPA VSD, bilateral conus, and side-side GAs

-w Taussig-Bing heart, hypertrophy & R deviation of conal septum, along w hypertrophy of the subAo conal free wall --> subAo stenosis, & is thus assoc w CoAo or Interr Arch; also MV may straddle the VSD, attach to subPA conus.

Doubly Committed VSD = 3-12% cases

-defect is close to both GA vlvs bc near absent conal septum

-VSD is superiorly located, often large

-semilunar vlvs = ant-sup margin of the defect

-the post-inf margins are formed by the septal band bc the VSD is cradled within it's limbs

-may have membranous extension

-pulm/Ao OTO uncommon

Noncommitted VSDs = 9-19% cases

-not cradled bn septal band limbs

-may be assoc w AVCD, be an inlet VSD

Conal Morphology

-important but does not determine if it is DORV (!)

-may have bilateral, subPA onlly, or subAo only conus, or no coni at all

-While Van Praagh, Kirklin, and Barratt-Boyes say it is the conal morph that is the 1y determinant of GA relationship, others disagree...

[ ] describe distance fr VSD to ea GA vlv, esp for bilat coni

-in subAo VSD, as conus size increases, then distance fr TV to Ao increases, and distance bn TV and PV decreases (thus less room for baffle)

[ ] conal septal morph- may have AV vlv attchmts precluding a baffle

-may deviate into one of the outflows to --> subAO or subPA stenosis, may be TOF like... or assoc w interr Ao or CoAo

GA Relationships

-Side by Side

-Ao Post/Rightward = Nly related

-Ao Ant/Rightward = d-MGA

-Ao vlv Ant to PA

-Ao Ant/Leftward = L-TGA

-Ao Post/Leftward = situs inversus totalis

-may be crossed or in parallel

-w subAo VSD, usually Ao R and either slight post or side-side to PA

-w subPA VSD, usually side-side and parallel, but Ao may be R and ant to PA

Assoc Lesions

[ ] OTO - present in up to 70% DORV

--> may need single ventric repair...

-most commonly w subPA obst, +/- valvar level, most often w a subAO VSD setting

-if pulm atresia, usually see the pulm trunk attached to the RV...

-check for CoAo/InterrArch- +in up to 50% w a subPA VSD

[ ] AV vlv xx

-common AV vlv - AVSD in 35%of DORV

-abNl MV = a top r/f for poor Px

-straddling MV - 20% of DORV if subPA VSD --> hard to do biventric repair

-parachute MV or supramitral ring- assoc w MS, affects long term Px of biventric repair

-mitral atresia w DORV rare, but --> def single ventricle path

-straddling TV

-cirss cross AV vlvs (rare)

[ ] other

-ASD

-LSVC

-leftward juxtaposition of atrial appendages

-common in pts w heterotaxy (usually R isom)

[ ] Cor art xx

-in up to 30% of DORV

-more w subPA or remote VSD

-side-side GA is also r/f for abNl cor arts

-can affect surgery- e.g. if crossing RVOT, if intramural cor art may complicate art switch

Pathophysiology

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-VSD physiology, TOF physiology, TGA physiology, Single ventricle physiology (if mitral atresia/ventric hypoplasia/unbal AVSD)

Imaging

Goals:

-VSD size & location

-VSD distance to GA vlvs

-AV vlv tissue bn VSD and GA vlvs?

-conal morphology- spatial relationshop of coni, size, orientation of septum, OTO?

-GA relationship

-assoc lesions?

-can demonstrate it is DORV (both GA fr RV) via:

-SC, AP4C, Parasternal sweeps in both long & short axis

-PSSA sweep to apex should be able to tell plane of the ventric septum beyond the VSD

-draw an imaginary line fr the IVS to transect the semilunar vls and determine degree of commitment...

Systemic & Pulm Vn Return; & Atrial Morphology

-2D/Color @ SC, PSSA, Suprasternal, R sternal views

-xx common if pt is heterotaxic

-DORV is assoc w L juxtaposition of atrial appendages, esp if Asc Ao and PA trunks are on at teh extreme R aspect of the heart

-SCLA, AP4C, PSSA sweeps will show atrial app relationships to GAs

-atrial septum may be abNlly perpendicular bc the perceived atrial septum is really the plane of separation bn the RAA and the LA or LAA

AV Canal

-@SC, AP, PS views

-ID straddling cords w sweeps of the VSD in LA and SA

-MV usually straddles an anterior conoventricular (outflow) VSD

-TV usually straddles a posterior AVSD

-SCSA, AP4C and PSLA and pSSA for parachute MV, supramitral ring

-Criss Cross AV vlvs in AP, SC, PS views

Ventricular Morph & Size

-check size to ensure biventric repair ok

-check diastolic AV vlv diameters

VSD Location & Size

-SC, AP, PSLA sweeps

-check relation to GAs

-for SubAo, subPA, DC VSD, the inf margin is usually the crest of musc spetum bn septal limbs

-post-inf margin - usually area of fibrous continuity bn TV and MV if there's a membranous defect, or it is the ventriculoinfundibular fold in continuity w the post limb of the septal band

-antero-sup margin- the GA vlv or subarterial conus

-check distance of VSD to GA vlv

-check for obstacles to baffle (short distance fr TV to the other GA vlv; AV vlv attchmts)

-check for remote VSDs- inlet or apical muscular- best seen in SC, AP, PS views

Conal Morph & OTO

-w subAS VSD- subPA stenosis - if leftward, anterior, superior deviation of conal septum relative to musc septum, along w conal free wall hypertrophy, like w TOF

-check subPA conus best in SC, AP, PS views

-check subAo conus- best in PSLA showing MV-Ao discontinuity

-also SCLA and SCSA if it is extensive, w ant, post, or side-side orientation of conal chambers

-w subPA VSD- subAo stenosis- if muscular tunnel from conal septum deviated to R, hypertrophied ventric-infundib fold and RV conal ant free wall

-SCLA, SCSA good to check

-Doppler outflow in SC, AP, R Parasternal to check amt of obst

-w subAS VSD and bilat coni, check TV to PA distance fr SC and PS views

-as subAo conus gets more elongated, the subPA conus gets smaller, so shorter TV to PV distance

-if the TV-PA distance is < Ao diameter--> obstruct the VSD-Ao baffle fr the infundibulum

-thus may need to resect conal septum for the baffle ,and place an RV-PA conduit (Rastelli)

-check for TV attachments to conus fr SC, pS views

Arterial Roots

-check relation w SCLA sweep w a completely horizontal probe orientation

-side-side GA- see them at same time

-ant-post GA-can't see them at same time, but appear separately in same area during sweep

-PS imaging - orient along the transverse plane of the thorax, instead of the PSSA plane of the heart, bc the oblique views gotten w the latter--> misleading w regard to spatial relationships!!

Coronary Arteries

-ID AbNl Cor arts, needed preop

-best in PSSA w high freq probe

-usually fr the two PA facing Ao sinuses...

-LMCA bifurcation into LAD & circ is important, bc common to have abNly w LAD fr RCA...

-no bifurcation--> c/s LCA abNl origin, or anterior or post to GA course...

-abNl of hte posterior cor art sometimes seen in SCLA or AP sweeps

-check for intramural cor arts too

Ao Arch

-CoAo & Interrupted Arch - check Suprasternal

-SSSA for arch branching, and LA for CoAo...

-high L parasagittal view (ductal view) w probe in vertical position--> good display of Ao isthmus at level of the CoAo

-check for PDA

-check Abd Ao Doppler for blunted upstroke or delayed return to baseline

PRENATAL ASSESSMENT

-#12 most freq fetal Dx, 62/2136 pts...

-often missed by OB US bc 4C view is usually Nl

-ventricular or GA size discrepancy may prompt investigation w fetal echo

-evaluate same anatomy as postnatal TTE

-may not have signif pulm OTO by Doppler, but color may show reversal of Nl Q in DA (fr Ao to PA), also if signif AS see reversal at arch

INTEROPERATIVE ASSESSMENT

-...preop TEE same as TTE goals

-postop

-after biventric repair

-residual VSD at patch

-Ao outflow obst, espec if preop anatomy had a small VSD or an elongated subAo conus, or staddling AV vls

-PR, espec p Rastelli or REV

-AV stenosis or regurg

-resid ASD/PFO

-ventric fx

Follow Up Assessment

-Long term xx to check for

-VSD- intramural defects- at margin of patch and RV free wall just below Ao vlv often can get resid xx

- often missed here, may not be there initially p op bc of residual RVH that later regresses...

-SubAS, espec if remote VSD

-Neo-Ao valv regurg or supraAo stenosis, ore neoAo root dilation after arterial switch

-AoArch obst p Co/Inter arch repair

-PS bc of conduit obst or p REV

-PR

-supravalvar PS or branch PA obst p art switch

-MR or MS p AVSD repair

-fx

Imaging the Adult

-few adults didnt have a repair

-hard to get good sub views...

-TEE, MR, CT helpful often...