Tricuspid Atresia, Stensosis, & Regurgitation (M/A)

Tricuspid Atresia, Stenosis, & Regurgitation (MA39)

TRICUSPID ATRESIA

-completely absent TV. No direct comm'n bn RA and RV

--> RV hypoplasia

--> obligatory R-->L shunt @ atria via ASD/PFO

--> obligatory systemic to pulm shunt (usually VSD, but can also be via PDA if concurrent pulm atresia)

-Uncommon

Path:

-pts are missing RV inlet bc it's formed by inflow

-RV is made mainly of the infundibular portion, and partly by the trabecular part

-if large VSD, then the trabec part can be better dvp'd--> larger RV; if no VSD, then --> rudimentary RV and pulm vlv will be atretic

-See a dimple in RA floor, w a muscular or fibrous membrane

-Wide ASD/PFO

-VSD's are usually perimembranous, but can also be muscular or AVSD

-If small VSD, can --> restricted pulm Q, pulm vlv stenosis/pulm annular hypoplasia, or sev RVOT hypoplasia

-If with dTGA, RV is subaortic so Qs can be restricted if small VSD

Classification

-Type I - Nl GA (70% pts)

-Subclassification:

-Type Ia - no VSD, +pulm atresia

-Type Ib - small VSD, some restricted Qp

-Type Ic - large VSD, no PS

-Subclass can change if VSD changes w time

-Type II - dTGA (12-25%)

-Subclassification:

-Type IIa - pulm atresia

-Type IIb - pulm stenosis

-Type IIc - no osbtructoin into the transposed PA

-Type III - (rare 3-6%) more complex assoc lesions- lTGA, malposed GA

-<20% pts have other CHD (less common w Type I)- CoAo (8% of TA), LSVC, juxtaposed atrial appendages, R Ao Arch

Physiology:

Normally Related GA's

-Complete mixing of vn return in LA.

-LV Q goes thru Ao and VSD (if present) to PA (or through PDA if no VSD)

-As PVR drops, pulm overcirc can occur.

-+cyanosis w all pts bc of obligate mixing, w amt of cyanosis d/o Qp, though d/o whether VSD is restrictive...; If no VSD, or pt has pulm atrsia, then Qp is thru PDA only and Qp d/o PDA size...

Transposed GA's

-Most get pulm overcirc within a few weeks of life bc usually no obstruction to Qp bc PA is fr LV

-restrictive VSD or infundibular narrowing --> obstruct Qs, and if severe--> shock

-if restricted ASD/PFO, --> hepatomegaly, and decr overall CO w decr Qp and Qs...

-CoAo --> decr LE pulses/perfusion

Sx/Si:

-cyanosis in all pts, apparent by end of 1st WOL (but less so if no obstruction to Qp)

-+/- murmur

-pulm overcirc sx and heart failure w decr PVR

-Hypercyanotic spells- bc decr in VSD size or infundibular narrowing (~to TOF spell; = need surgery)

-dTGA --> Sx of pulm overcirc; hard to DDx (by exam) fr Type I if large VSD

-Nl size newborn

-LV impulse more prominent than RV

-+thrill if restrictive VSD

-Single S1, accentuated

-often Single S2

-Holosyst murmur if Q thru VSD or ejection murmur if RVOT

-w incr Qp, can hear S3 or middiast rumble at apex

-hepatomegaly, esp if restricted PFO/ASD

ECG:

-ECG can help w DDx of cyanotic newborn:

-RAE- may or may not be present initially, but occurs in older infant/kids

-no relationship bn P wave and restricted ASD/PFO

-BAE in pts w incr Qp

-Nl PR interval

-QRS frontal plain axis is R and Inf w prominent RV forces in MOST cyanotic hrt dz pt, BUT in Tri Atresia, it is LEFT and SUP, especially in Type I (85% of them have LAD on ECG)

-in Type II, frontal plane QRS axis is evenly divided bn L-S axis and an L-I axis

-if incr Qp, often tall R and deep Q in V6, and if decr Qp have small R and Q waves

-Some pts (often older) --> biphasic/inverted T wave at V5,6 +/- ST depression, but not necessary assoc w myocardial dysfx so ? importance....

-Usually Sinus rythm

-tachyarrhythmia- aflutter/fib seen in older kids esp if restricted atrial septum w big RA, and they are common post Fontan in up to 1/2 pts

CXR:

-Nl heart size, then cardiomegaly if incr Qp bc of volume load on LH, and show prominent pulm vasc markings.

-if obstructed Qp, --> decr vasc markings

-globular shaped cardiac silhouette w concavity at MPA region

-RH border prominent bc of RAE, esp in older infant/kids

Echo:

-check LV size/fx - often dilated; decr fx if prolonged vol OD/hypoxemia

-Check TV anatomy- imperf linear echo denisty at TV site

-2 semilunar valves and GAs unless pt has pulm atresia too

-check GA relationship and coronary origin

-check VSD size, and SD/PFO size/restriction (to c/s cath balloon septost)

-check assoc lesions- CoAo

-Doppler- confirm no RA to RV Q, check atrial shunt, check pulmonary Q/PS, check VSD restriction

Cath:

-less need bc of echo

-check source of Qp

-balloon septostomy PRN

-Prominent a wave in RA, esp w restrictive ASD/PFO

-dTGA pt- check pulm art htn, check VSD...

Angiography

-Right atriogram or SVC-gram --> no Q fr RA to RV (not needed anymore usually)

-helpful to ID VSD location and source of Qp

-check PA size

Treatment:

-Goals of initial surgery: provide Qp enough to avoid hypoxemia, prevent pulm overcirc/htn and subsequent LV failure and PVD, and preserve pulm art anatomy for later surgery

-PGE1 if sev restricted Qp for PDA until 1st surgery

-PGE1 xx- apnea, sz, f, hypotension fr periph vasodilation

-Newborn:

-Type Ia & Ib (restricted Qp...) - AP shunt

-BTS (classic)- subclav art to PA in end to end --> hard to maint patency

-Potts shunt- window bn Desc Ao and distal LPA --> distorted PA, CHF, LV dysfx, phtn

-Waterston shunt- window bn Asc Ao and prox RPA --> distorted PA, CHF, LV dysfx, phtn

-Modified BTS- Gore-Tex tube- procedure of choice - LV dysfx and PVD are rare

-Central Shunt- prosthetic tube bn Asc Ap and MPA thru a sternotomy- sometimes used

-Type Ic (free Qp) c/s PA band and watch for shrinking VSD

-Type II (dTGA)

-Type IIc (dTGA + unrestricted Qp)

-PA band to prevent pulm overcirc,

-and follow VSD size. If too small:

- c/s enlarging it if needed for Qs

- c/s MPA to Asc Ao anast. (like a DKS)- MA anast to Asc Ap and branch PA's detached fr MPA, with Qp supplied by an AP shunt. --> LV output goes to Ao via VSD/Ao vlv and thru MPA to Ao

-Glenn (1965)- SVC to distal RPA anast- initially by detaching SVC fr RA and detaching RPA fr MPA, w end to end anast. So RPA gets Q fr SVC only, and LPA fr mixed systemic/pulm vn Q via the MPA--> prevented severe hypoxemia and no risk of phtn bc Q to RPA is venous. Still, they had R-->L shunt at IVC & pts got bad AVMs years later worsening cyanosis...

-Fontan & Baudet (1971)- (classic Fontan) completely separate syst and pulm circuits w a Glenn to RPA and with attaching RAA to LPA (!) to direct IVC Q into LPA, via a homograft valve, and then close ASD.

-Kreutzer described doing same thing but anast RAA directly to MPA w a semilunar valve in bn

-"Fontan" has come to mean any surgery that routes systemic venous Q to the lungs without passing thru a ventricle

-Choussat (1978) criteria for a classic Fontan: (some no longer needed for good result)

-Age bn 4-15yo *modified Fontan done at <4yo

-Nl sinus rhythm

-Nl systemic venous connections *mod Fontan done in pts w abNl vns

-Nl RA size

-Nl PAP (mean <15)

-Low PVR (<4Woods)

-Adequate PA diam (>75%Ao diam)

-Nl LVEF (>60%) *mod Fontan- relative c/i xx

-No MR *mod Fontan- relative c/i xx

-No complications fr prior surgery (e.g. PA distortion)

Fontan effects:

-signif incr RA P, to equal MPA P

--> xx: persistent pl effusions - partly bc changes to lymphatic drainage

-any incr PVR--> decr LA/LV filling--> decr Qs

-Bidirectional Glenn - now often used

-SVC to RPA that allows Q to R and L PA, w IVC still going to RA and then LA

-advantages: Q to both lungs, decr vol load on LV, prevent PA distortion

-Later on, a complete Cavopulmonary anastomosis w IVC to PA

-Tunnel thru RA to sent IVC Q to RA thru anast underneath the RPA

-avoid sharp turns/obstructions to improve fluid dynamics and keep from loosing energy...

-Extracardiac conduit fr IVC to RPA

-Better than classic Fontan bc it eliminates teh dialted syst venous reservoir w elevated RA P that --> sluggish Q and thus thrombi/arrhythmias (a-flutter)

-However, force of Q thru Fontan will be <Nl, so remove all obstruction- e.g. stent stenosis w cath 1st...,

-Modified Fontan xx

-arrhythmias- maint NSR w Rx or ablation if needed, or surgery for a-flutter

-Consider placing a Fontan fenestration to pulmonary venous atrium- Q to bypass lungs to ensure adequate filling of LV at expense of incr cyanosis, and then close later postoperatively

Prognosis:

-10% 1yr survival if no stage 1 palliation- d/o type

-50% survived till adulthood until modified Fontan

-Now, w modified Glenn/Fontan- outcome varies d/o initial anatomy/hemodynamics

-overall mortality of pt with any single ventricle physiology who got Fontan is 7-11% (? how long out??)

-Some pt--> collaterals (art and venous)

-elevated venous P--> small venous channels fr RA/IVC/SVC to dilate--> R-->L shunt, can --> systemic desat; can't always occlude at cath...

-Desc Ao systemic art collaterals- to pulm art tree --> competition for low P Q fr Fontan

-PLE- ?mech, --> hypoproteinemia, ascites, periph edema

-changes in RA P, and lymphatic drainage/hydrostatic P

-Tx: steroids, heparin- success varies

-Tx: albumin PRN, medium chain TG diet helps, but nothing--> long term benefit

-Fontan--> improved exercise tolerance postop, but still not Nl

-no RV, decr LV fx, impaired chronotropic response, conduit obstruction, abNl PVR

-Rec anticoagulation bc of decr RH flow even in the best cases

-Rec AL reduction w ACEI, esp if LV dysfx

-? if operating at younger age will help bc less ch hypoxemia an LV vol OD

-Transplant still an option in pt w tri atresia

TRICUSPID STENOSIS

-assoc w other xx- RVOTO, RVOT atresia w 2y hyopplastic RV

-Some DDx TV stenosis (big annulus, thick/fused leaflets w short cords) vs hypoplasia (small annulus, w Nl leaflets/cords)

-Isolated TS is rare, often due to rh hrt dz fr childhood

-Sx similar to tri atresia, as is ECG

-Must DDx Tri atresia and TS for surgical options

EBSTEIN ANOMALY

-#1 TV xx

-0.5% of CHD, M=F

-assoc ASD/PFO, VSD, PS/PA sometimes

Path:

-variable morphology

-Septal and Post Leaflets displaced into the RV

-a small amt of the valve cusps are free if there's substantial adherence of the leaflets to RV wall

-if a large part of cusps are free, then --> redundancy of valve

-Ant cusp Nl usually

-Atrialized part of RV is above the part of the valve pushed into RV....

-Septal leaflet usually rudimentary in sev cases, but is just thick in milder cases.

-Post leaflet thick w abNl cord attchmts that tether it to RV wall in sev cases

-Ant leaflet often large, redundant (sail)

-AbNl cord attchmt to Ant & Post leaflet --> sev TR

Physiology:

-variable bc of variable physiology

-mild displacement of TV--> little TR, ASx, survive into adulthood w/o Tx

-sev displacement of TV--> cyanosis fr R-->L shunt at atria bc RAP >LAP - bc poor RV filling bc of redundant TV leaflets and TR, poor RV filling bc abNl contraction of atrialized part of RV.

-In atrial systole, bld flows fr RA to atrialized RV, then during ventric systole, much of this is pushed backward to RA instead of thru TV to RV..., so decr Qp

-As Neonate, PVR is high, further inhibiting Qp --> fxl pulm atresia ==> signif cyanosis, and pt is PDA dependent, but improves as PVR drops

-Cyanosis thus improves until teens when pt becomes even worse, likely bc of incr TR--> incr RAP--> incr R to L shunt... & worse TR--> worsens TR, thus vicious cycle...

-If initial intact atrial septum--> no cyanosis, and Sx d/o degree of TR and TS; HSM and prominent a wave and JVD

Sx/Si:

-? if truly more common in mom's taking Lithium

-Can have sev CHF/cyanosis early and even in utero, while mild xx--> mild Sx

-Sx improve as PVR drops usually, but can return later w DOE, tired, cyanosis

-20-30% have tachycardia, and can incr Sx if poor RV filling and thus decr Qp

-JVD w prominent a waves if limited atrial shunting

-HSM

-may have systolic thrill

-S1 usually Nl or diminished and often widely split, 2nd part is TV closure and usually louder than 1st

-holosys murmur in most pts bc of TR

-SEM fr RVOTO might be heard

-S2 Nl but widely split if RV conduction delay, might not hear P2 if decr Qp

-Loud S3 common - ? etiology- RV filling or vibrations fr abNl vlv leaflets

-middiast murmur = some true or relative TS

-Loud S4 possible too

ECG:

-RAE w peaked P waves; wider to notched if marked RA dilation (c/s combined atrial enlarge)

-Often see R sided accessory pathway w deltawave..., if no WPW, it is bc of RV conduction delay (RBBB).

-Rightward QRS axis, but can be Nl/slight leftward

-+/-RVH, but not common; no LVH, Nl QT

-Arrhythmias: WPW, a-flutter/a-fib if sev dz, wantering pacemaker, ventricular ectopy

CXR:

-Can be Nl, or signif CM w decr pulm vasc markings

Echo:

-Delayed TV closure compared to MV, paradoxical motion of IVS, incr RV size, incr MV ant leaflet excursion -- not specific findings, relate mainly to RV vol OD

-Check TV, shape/motion...