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Centro Cardiovascular Pediátrico Clínica Santa María Santiago Chile Dr Luis León M. Dr Stephan Haecker D. Dr Daniel Pérez I. www.cardiopatiascongenitas.cl. VSD PATCH ANNULOPLASTY. FOR COMPLETE ATRIOVENTRICULAR SEPTAL DEFECT. ¿ which goals does a good surgical technique achieve ?.
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Centro Cardiovascular Pediátrico Clínica Santa María Santiago Chile Dr Luis León M. Dr Stephan Haecker D. Dr Daniel Pérez I. www.cardiopatiascongenitas.cl
VSD PATCH ANNULOPLASTY FOR COMPLETE ATRIOVENTRICULAR SEPTAL DEFECT ¿ which goals does a good surgical technique achieve ?
CAVSD: Inlet VSD Primum ASD Common AV valve
Type A CAVSD: Common AV valve with chordae inserting on the VSD crest, and divided leaflets
Type C CAVSD: Common AV valve with anterior and posterior bridging leaflets
Leaflets are sutured to the upper border Of the VSD patch
SURGICAL ISSUES Distortion of the mitral valve
After the VSD is closed the new mitral valve has three leaflets: a mural leaflet and two hemi bridging leaflets Syringe flushing of saline will float these leaflets to a closed position. This isn´t the same as in a beating heart, since it is in a cardioplegic state.
Floating shows us the diastolic geometry of the mitral valve
The area where leaflets become in contact with each other is the coaptation zone also called the “kissing edge”
Floating leaflets reach into each other and touch in the coaptation zone, in red This makes a competent mitral valve
¿ how does surgery alter the mitral valve ? Suturing the leaflets to the VSD patch uses 2 or 3 mm of valve tissue
A VSD patch which is higher than the valve uses more valve tissue and shortens both hemileaflets even more
There is more leaking along the mural border and central area
Again, a high VSD patch tethers the leaflet tissue and loses the coaptation border as shown
An excessively long VSD patch brings the hemileaflets apart valve area is larger hemileaflets lose their coaptation border along the mitral cleft
Leaflets will be subject to greater tension due to a larger annulus They will lose mobility
Again this will result in incompetence due to loss of coaptation zone
In the end leaflets will need to be approximated by means of additional commisuroplasties This is like using the accelerator, and then applying your brakes to save the situation
SURGICAL ISSUES Distortion of the coaptation border
Dividing the anterior bridging leaflet in type C CAVSD leaves us with two hemleaflets
And two more after divididing the posterior bridging leaflet
Floating shows the divided leaflets in good contact A wide coaptation border results in a competent mechanism
suturing the free border of the mitral cleft distorts normal function and puts tension on the subvalvar chordae this is not an uncommon mistake
CHANGES OCCURRING IN THE BEATING HEART
The Common AV valve in motion
In the normal heart mitral and tricuspid valves have independent valve rings
there is a common AV valve ring in CAVSD whether type A or C
SURGICAL ISSUES The surgically created mitral ring
Let us look at mitral ring geometry after our intervention We have placed our VSD patch to the right of the ventricular septum and given some more valve tissue to the mitral valve
In the cardioplegic heart the patch looks centered The new mitral ring is outlined in white
¿ what about systole ? In the beating heart the mitral annulus acquires a new geometry It shortens along the ventricular wall but it bulges along the septum
¿ what have we produced ? ¡ an entirely new mitral ring geometry !
Hemileaflets are pulled to the right side Hemileaflets lose their coaptation with the mural leaflet
Having said all this: MY FAVORED SURGICAL TECHNIQUE
Both cavae are cannulated so as to have the right atrium fully exposed The often patent duct is always dissected and interrupted on bypass, an LV vent is placed in the LA away from the common AV valve
Step One: asigning valve tissue to mitral and tricuspid valves the VSD patch will be placed to the right side of the septum, the valve is floated and a division line is proposed