Download Left Ventricular Outflow Tract Obstruction- Single Vs Bi

Uni-ventricular versus Complex
Biventricular Repair for Neonates with
critical AS
Hani K. Najm MD, Msc, FRCSC, FRCS(Glasg)
King Abdulaziz Cardiac Center
National Guard Health Affairs, Riyadh Saudi Arabia
Critical LVOTO
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Despite being one of the most
common congenital cardiac
abnormalities, the treatment of
critical left ventricular outflow
tract obstruction (LVOTO) in
the neonate and infant remains
a significant challenge.
McCrindle BW, et al. Circulation 2001;104:I152—8.
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Why this can be a difficult decision:
Obstruction of the left ventricular out flow
tract is a spectrum of diseases which may
be present at varying degrees at diffident
levels
But
The decision has to be dichotomous
Univentricular or Biventricular
Wrong choice may mean early or late poor
outcome or death
Contraindication of Biventricular
Repair in Congenital AS
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Small left ventricle
< 20ml / BSA, Inlet length < 25mm
Narrow aortic valve ring
< 5mm
Small mitral valve orifice
< 9mm
Extensive fibroelastsis
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
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“ “Those patients who have “Borderline Left
Ventricle” need to be carefully evaluated for
suitability of single or biventricular repair based
Morphometric
functional parameters
haemodynamic data
available surgical options
results of the personal/Institutional experience
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
In clinical practice, we face the problem of
“border line left ventricle” in 4 different groups of patients
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Critical aortic valve stenosis
Aortic coarctation with or without hypoplastic arch
Hypoplastic left heart complex
Right ventricular pressure/volume overload
 TAPVR
 Unbalanced AVSD
 Cortriatriatum
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Surgical Options
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Biventricular repair (BVR)
 Surgical aortic valvotomy
 Balloon aortic valvotomy
 Ross, Ross/Konno
 Arch repair ± repair other lesions
Single ventricular repair (Norwood type)
BVR after Initial single ventricular repair
-Staged or primary repair
Cardiac Transplantation
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Surgical repair for LVOTO depends upon
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Level of obstruction
Associated anomalies
Morphometric parameters
Functional parameters
Ability of LV to sustain systemic circulation
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
What is “Borderline Left ventricle”
Morphometric parameters
Mitral valve diameter < 11mm
Indexed mitral valve area < 4.75 cm2/m2
LV inflow dimension < 25mm
LV cross sectional area < 1.6 cm2
Ratio of LV apex-base and RV
dimension < 0.8
LV long axis/Heart long axis < 0.8
LV end diastolic volume index < 20ml/m2
LV mass index < 35gm/m2
Endocardial fibroelastosis
Cardiac apex not formed by left ventricle
Diameter of the LV-Aortic junction <
5mm
Ratio of RV:LV wall thickness
Functional parameters
Left ventricle ejection fraction < 40%
LV end diastolic pressure > 20mm Hg
Mean pulmonary artery pressure >
50mm Hg
Direction and flow in the ascending
aorta and at PDA level
(Corno ‘et-al’, EJCTS,27(2005),67-73)
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Rhodes Score
Risk Factor
LV/Heart long axis ratio
Indexed aortic root diameter
Indexed mitral valve area
LV mass index
Threshold value
0.8 or less
3.5cm/m2 or less
4.75cm2/m2
35gm/m2 or less
“14(BSA)+0.943(RI)+4.78(LAR)+0.157(MVA index)-12.03”
BSA= body surface area, RI= root index, LAR= long axis ratio, MVA=mitral valve area
Overall threshold value of Rhodes score= <0.35
“Two
or more factors or additional anatomical factors below threshold
value are associated with 100% mortality if BVR is attempted with
overall predictive value of 86%”
(Rhodes ‘et-al’,Circulation 1991;84:2325-35)
Pitfalls of Rhodes scoring system
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Based on retrospective observations
Antegrade aortic flow not considered
Ductal shunting was not taken into consideration
Not applicable to aortic arch obstructions
Does not address
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Tricuspid regurgitation
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Degree of endocardial fibroelstosis
(Tani’et-al’, JTCVS 1999;118:81-6)
Study period-1994-2000
N==320 neonates with critical LVOTO
Initial intended bi-ventricular pathway (n=116)
Initial Norwood pathway (n=179)
Objective-To determine factors that would predict whether a bi-ventricular repair
or Norwood procedure pathway would give the best survival in
neonates with critical aortic stenosis
(Lofland’et-al’, JTCS 2001;121:10-27)
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Percent Survival n=116
BVR Group
Risk-adjusted percent survival
stratified by the grade of endocardial
fibroelstosis from 0 to 3 (at aortic
valve z-score set to –3). BVR Group
Risk-adjusted percent survival
stratified by z-value of aortic valve
at sinus of ‘Valsalva’
BVR Group
Risk-adjusted percent survival stratified by
the patient’s age (in days) at the
admission. Aortic valve diameter z-score
set at (-3) and grade of fibroelstosis set at 1
BVR Group
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Norwood Group
(n=179).
Risk adjusted percent survival stratified by the diameter
of ascending aorta above the STJ. TR set at absent
Norwood group (n=179)
tricuspid regurgitation. The diameter of
aorta was set at 4mm.
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Independent factors predictive of percent survival benefit at 5
years after entry for Norwood procedure versus biventricular
repair
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Higher grade of endocardial fibroelastosis, p<.001
Lower z-score of aortic valve at the level of the sinuses of Valsalva, p<.001
Younger age at entry, p<.001
Larger ascending aorta diameter (mm) p<.001
Absence of moderate or severe tricuspid regurgitation, p<.001
Lower z-score of the LV length-p-0.02
Left Ventricular Outflow Tract ObstructionSingle Vs Bi-Ventricular Repair
Calculator
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Step 1: Please fill in the following information for your neonate to
calculate an estimate for survival difference.
Critical AS web calculator is available at www.chssdc.org
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Patient DOB (mm/dd/yy)
Weight at initial echo:
Height at initial echo:
Mitral Valve Annulus: measured in long-axis view: (cm)
Is there a large VSD?: Yes/No
Grade of EFE: None, Mild, Moderate, Severe
Diameter of aortic valve at the level of sinuses of Valsalva: (cm)
Diameter of ascending aorta: (cm)
Moderate or Severe Tricuspid regurgitation: No,Yes
Left ventricle length: (cm)
Step 2: Click on the calculate button to determine the estimate.
The number is the difference in percent survival at 5 years after entry for Norwood versus
biventricular pathway.
A positive number means that 5 year survival with the Norwood procedure is better for the patient.
A negative number means that 5 years survival with biventricular repair is better for the patient.
1994-2001
Critical LVOTO as
predominant lesion
N=362
UVR=223
BVR=139
UVR: Risk
factors for death
BVR: Risk
factors for death
Survival %
Patient X: Predict UVR survival
UVR
Risk factors: UVR BVR
Years
Patient X: Predict BVR survival
Survival %
BVR
UVR
Risk factors: UVR BVR
Years
UVR Survival advantage
(UVR-SA)
Survival %
BVR
UVR
UVR survival
advantage= - 25%
Years
Distribution of UVR-SA
predictions in the CHSS
cohort?
BVR
favoured
21% UVR “Discordant”
- better predicted survival with
BVR
-80
0
UVR-SA Score
Number of patients
UVR: distribution of UVR-SA
values
+80
Number of patients
BVR: distribution of UVR-SA
values
-80
UVR
favoured
56% BVR “Discordant”
- better predicted survival with
UVR
0
UVR-SA Score
+80
What are the survival
consequences of “discordant”
management?
Survival %
UVR Discordant: actual survival
Years
Survival %
UVR Discordant: predicted
survival with BVR
Survival difference: 70% vs 56%, P=.02
Years
Survival %
BVR Discordant: actual survival
Years
Survival %
BVR Discordant: predicted
survival with UVR
Survival difference: 81% vs 60%, P<.001
Years
Mortality
Discordant UVR vs. Discordant BVR
Discordant BVR is associated with greater
mortality P<.01
Biventricular Repair After
Norwood Palliation
Biventricular Repair After Norwood Palliation
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A subset of patients, usually neonates with VSD, may have
adequate LV and mitral valve size, making them suitable for
future biventricular repair. (8 out of 58)
Biventricular repair consists of a Rastelli-type procedure either
concomitantly or as a staged procedure and also involves
enlargement of VSD and closure usually at 4-11 months after
initial palliation.
Identification of potential candidates is critical.
Pearl ‘et-al’, Ann Thorac Surg 2003;75:132-7)
Biventricular Repair After Norwood
Palliation
(Pearl ‘et-al’, Ann Thorac Surg 2003;75:132-7)
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Thirty-five consecutive infants with
severe LVOTO underwent complex
biventricular repair
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Ross (n = 21)
Yasui (n = 14) procedure.
Follow up at 1 month
Am Heart J 1997;13
Conclusions
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The spectrum of critical LVOTO is a challenging problem with
substantial morbidity and mortality despite the dramatic
improvement in management
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The identification of variables that impact upon outcome will
assist in selecting most appropriate therapy for a successful
management. (www.chssdc.org)
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The preferential pursuit of BVR in borderline cases is expensive
in survival terms
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There is a bias towards BVR
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The UVR-SA prediction model will improve the triage of
newborns with critical LVOT obstruction