Mavroudis VSD

Pathophysiology

-incr Qp, by 2-3yrs --> irreversible pulm vascular obstructive dz, w eventual PVR>SVR so R-->L shunting w cyanosis then death

-Restrictive VSD usually ASx, questionable whether/when they should be repaired

-Irreversible pulm vasc dz does not usually occur before 1-2yo

NHx

-d/o VSD size, amt of shunting, and PVR

-Most restrictive VSD (<0.5cm diam) usually get smaller and close spont'ly by 1yo

-close via fibrosis of the margins 2y to hemodynamics at the site, or by TV septal leaflet adhearing to the defect to ---> tricuspid tissue pouch, or by muscular bundly hypertrophy

-Most that close do so by 1yo, remainder by 5yo, then spont closure is rare

-xx is occlusion via prolapsed Ao vlv cusp, bc can --> AI = indication to close soon

-larger vSDs- Sx soon after birth as PVR drops, w CHF Sx..., then Sx of incr PVR over time later on, w irreversible pulm vasc dz after 1-2yo, and eventual Eisenmenger syndrome w PVR>SVR, R-->L shunt at VSD, and RV failure (Eisenmenger usually doesn't occur till 20s or so, w death by 40yo)

-Some have an isolated VSD but get subpulmonary stenosis bc of RVH --> TOF like Sx

-but decr risk of pulm vasc dz bc of pulm vasc bed protection (self banding)

-Bacterial Endocarditis (rare - 0.3%/yr/pt) - usually at the TV septal leaflet; = immediate indication to close once the infection has resolved, regardless of size

-Thus prophylactic closure of restrictive VSD controversial bc the BE risk

Dx

-loud holosys M loudest at LSB (size doesn't correspond to murmur intensity)

-incr PVR--> shorter, softer, limited to early systole, or gone entirely, w a loud S2 fr P2

-may have big liver and JVD

-CXR- CM d/o amt of shunting

-Echo...

Rx Tx

-diuretics, AL reduction...

Indication

-Large VSD w bad CHF- close by 3mo

-Large VSD w CHF responsive to Rx- follow till 6mo, bc by then spont closure less likely and pulm vasc dz risk is only increasing; especially if PVR is >4Wu by now or Qp:Qs 2:1

-Large VSD in older pt and established pulm vasc obst dz- usually had some pd of improved Sx as the Qp decreased some as PVR rose. If PVR is already at 8Wu & no response to vasodilators, then they are not a surgical candidate.

-Small VSD in Infants- usually no Tx needed/little Tx needed- follow to see if ti shrinks/closes, and then if paramembranous or muscular recheck after 1yr for signs that would indicate need to close-

-new data supports a more liberal indications to close- any Ao vlv prolapse even w/o AI, h/o prior endocarditis, any ventric dysfx even if Qp:Qs <2:1 (mainly bc surgery carries a low risk, likely less than that of long term bacterial endocarditis risk)

-Conal VSD- high probability of Ao vlv prolapse and AI, espec p 5yo, so close early to prevent this, close regardless of VSD size

Surgical Closure

-5 Approaches:

-RA

-Transpulmonary

-Transaortic

-RV

-LV

-RA Approach

-most common approach, for: paramembranous, inlet, muscular and LV-RA defects

-with VSDs behind the TV septal leaflet, you must ensure you fully expose the VSD (by incising the TV leaflet, taking care not to touch the the Ao leaflet that might be prolapsing thru the VSD), because it is easy to confuse an opening bn the TV cords as the VSD, then a surgeon would stitch close that, leaving the true VSD open.

-use superficial sutures at the post/inf margin of the VSD so as not to damage the conduction system, from the insertion of the muscle of Lancisi to the TV annulus near triangle of Koch apex.

-place buttressed sutures fr teh RA inward, thru the septal TV leaflet, about 1-2mm away fr the annulus, running fr the pt of insertion of the muscle of Lancisi, to the triangle of Koch apex. Continue sutures superiorly twd the transitional area where the sup edge of VSD starts to be formed by the infundibular sepal muscle. At this pt the risk to conduction system xx is minimal, but there is more risk to Ao vlv damage. Don't place the sutures through the remnants of the membranous septum in the post-inf angle of the defect bc it has high risk of conduction xx. Also, don't place sutures through the fibrous rim on the crest of the defect, bc it lacks holding qualities.

-Transpulmonary Artery Approach

-usually for supracristal (conal) defects

-same technique for bypass and myocardial preservation as for RA

-Vertical Incision thru PA

-Must use patch closure for conal defects- it supports the prolapsing Ao vlv and prevents continued downward pressure on the leaflets.

-Complete closure of VSD shunt eliminates the Venturi effect that pulls the Ao vlv cusp into the VSD

-Don't be fooled if the Ao cusp partly occludes the VSD making it look like you can stitch close it

-At superior aspect of the VSD, the Ao-Pulm valve jct does not allow for suturing, so anchor a few stitches thru the base of the pulmonic valve cusp at the jct w the valvar sinuses, where the small pledgets will rest against the arterial valve, decreasing risk of the suture tearing thru the thin valve tissue.

-A combined trans-Ao-TransPA approach for concomitant surgical repair of AI is also advocated

-The patch should'nt interferew the Pulm Vlv fx, and should give support for the Ao vlv which was previously prolapsed.

-TransAortic Approach

-usually done if need to also correct assoc lesions- Ao valvuloplsty for prolapse, valvar/subalvar stenosis

-Make an oblique, curved incision fr ant aspect of asc Ao above Ao vlv commissure, above the center of the R cor sinus. Beware of the cor sinus ostia that may arise higher than expected in the sinus.

-then cut infly and to the R, then transversely and twd the L if needed.

-Or, transect it 1-2mm above the Ao commissures, to mobilize the prox Ao ant'ly and maximize trans-Ao view.

-Retract Ao vlv leaflets to expose the defect

-If the fibrous or muscular rim of the VSD is absent at the superior aspect, then it is hard to suture, so use mattress sutures buttressed w pledgets thru the Ao wall fr the inside of the Ap's sinuses.

-RV Approach

-not commonly used for isolated VSDs

-can be transverse - ? better bc less inury to circular muscle fibers, but limited exposure & doesn't allow for enlargement of the infundibulum with a patch if needed

-can be vertical - should be limited to the indundibulum only, starting at ant aspect & going up/down

-Must examin epicardial cor art distrib b4 ventriculotomy. Check LAD origin fr L main cor art, bc sometimes it can arise as a branch of the RCA and cross the infundibular wall, or have dual supply w one branch fr LCA and another fr teh conal artery off the RCA, both ==> avoid ventriculotomy

-RV Approach Indications:

-Can't get to it fr RA or PA

-VSD extends superiorly into the infundibular septum

-Improve exposure in the presence of obstructive infundibular muscle bundles

-Can't expose the inf margin of a conal defect well

-LV Approach

-Rarely used, limited to certain trabecular VSDs w multiple apical defects (Swiss cheese...)

-may be easier to patch fr LV surface bc it is smoother than RV

-Vertical Incision - (more common) start at LV apical area going superiroly

-Transverse Incision also possible

-much watch cor art distrib