Analisis de la curva de aprendizaje y resultados clinicos de TAVI
Flavio Ribichini
Universidad de Verona
LEARNING CURVE ANALYSIS IN TAVI EXPERIENCES
Why is it important?
- Given the exponential growth of the workload represented by the elderly population with
AVS more centers are rapidly being involved in TAVI and the increment of human and
economic resource consumption imposes a careful monitoring of clinical outcomes and
cost-benefits balance.
LEARNING CURVE ANALYSIS IN TAVI EXPERIENCES
Since 2011 only few studies have been published
- Most of them compared the early experience with later experience using the χ2 test, and not a time
series analysis
- Since last year, there are some analysis of TAVI learning curve applying a more appropriate
statistical tool, called CUSUM
- This method reports graphs of changes in outcome rates over time and allows to understand exactly
when, during the experience, the benefits overhead complications
Gennaio 2010
Febbraio 2010
Marzo 2010
Luglio 2010
Gennaio 2011 Luglio 2011
Marzo 2012
Settembre 2012
Gennaio 2013
Delibera della
DG per il
Progetto TAVI
Training del Heart Team a Rouen per valvole Edwards 22-3.02.2010
Prima TAVI con valvola Edwards a Verona con supporto del Dr. Eulogio Garcia di Madrid 15.03.2010
Prima TAVI con valvola Edwards a Verona in autonomia 14.07.2010
Marzo 2011
Prima TAVI completamente percutanea (23.01.2011)
Training del Heart Team a Laussanne per le CoreValve (16-17.03.2011)
Primo impianto di CoreValve eseguito in emergenza per Insufficienza Aortica acuta il 22.07.2011
Prima TAVI eseguita in anestesia locale 14.03.2012
Trattamento di aneurisma dell’aorta ascendente con insufficienza aortica grave con CoreValve 19.09.2012 Trattamento valve in valve di bioprotesi degenerata in sede tricuspidale con valvola Edwards 23.01.2013
The learning curve is a “moving target”
Gennaio 2014
Giugno 2015
Gennaio 2017
Eliminazione del catetere vescicale sistematico pre-TAVI
Giugno 2016
Prima TAVI senza impianto di PM temporaneo in VD
Prima TAVI VIV con impianto simultaneo di stents coronarici
Eliminazione dell’assistenza UCIC sistematica post TAVI
Dicembre 2015
Contratto Edwards -Ospedale di Verona come European Ceter of Excellence (COE) x TF TAVI
Prima TAVI TF in Week Surgery (in-out in settimana)
Aprile 2017
The learning curve is a “moving target”
2011
First half: 1-135 Second half: 136-270
2012
Early: 70 Late: 70
Surgical risk scores do not predict accurately mortality and morbidities (trend to understimate) in the first phases of learning curve.
2014
More than 70 TA cases
2015
2015
Only descriptive data with difficulties to find out the correct number of procedures needed to improve outcomes, because of the lack of a specific statistical method.
2015
Only three published studies applied CUSUM analysis
Letter to the Editor
What is CUSUM?
CUmuative SUM of failures
A method to monitor operator’s performances over time
Originally developed for industry…
…then fitted to surgery
Operation number (sequential from the first to the last)
Cu
mu
lati
ve n
um
be
r o
f fa
ilure
s (n
)
0
Total operations
To
tal fa
ilure
s
- Is the failure rate acceptable? - Is there an identifiable proficiency cutoff?
The CUSUM method
What is CUSUM?
CUmuative SUM of failures
Prerequisites: - Define what is a procedural “failure” - Define an acceptable failure rate (p0) - Define an unacceptable failure rate (p1)
Compute “upper”(l1) and “lower”(l0) limits
Typical Cumulative Failure Chart
l1
l0
Cu
mu
lati
ve f
ailu
res
(n)
Operation number (n)
Prerequisites for TAVI: - Define what is a procedural “failure”
- Define an acceptable failure rate (p0) - Define an unacceptable failure rate (p1)
Typical Cumulative Failure Chart
VARC II
30-days VARC II safety
p0=20% p1=30%
VARC II Device Unsuccess
p0=10% p1=20%
CUSUM – VARC II Early (30 days) Safety
STS Score <9 pts
TAVI progressive number
Cu
mu
lati
ve F
ailu
res
Any Risk
Cu
mu
lati
ve F
ailu
res
CUSUM – VARC II Device Unsuccess (with any type of dual valve need)
STS Score <9 pts
TAVI progressive number
Cu
mu
lati
ve F
ailu
res
Any Risk
Cu
mu
lati
ve F
ailu
res
Initial Experience obtained in 177 high-risk patients To identify acceptable and unacceptable failure limits, end-points incidence reported in seminal high-risk TAVI trials was analysed (Partner ‘B’, US Pivotal Trial,CHOICE Trial) and used to calculate the boundaries for the control charts.
1.
Formal proficency obtained at TAVI n 54.
Formal proficency obtained at TAVI n 50 for Edwards valve, and at TAVI n 36 for Medtronic one.
Formal proficency obtained at TAVI n 32.
2. Formal proficency with Edwards valves obtained at TAVI n 86 as to 30-day safety end-point
Formal proficency with CoreValve obtained at TAVI n 40 as to 30-day safety end-point
Learning curve of 6 operators Verona: learning curve 2 operators
3.
3.
Better results with TA TAVI obtained at n 128 as to 30-day safety end-point
TAVI IN 150 INTERMEDIATE RISK PATIENTS: - Define what is a procedural “failure”
- Define an acceptable failure rate (p0) - Define an unacceptable failure rate (p1)
Typical Cumulative Failure Chart
VARC II
30-days VARC II safety
p0=20% P1=25%
VARC II Device Unsuccess
P0=6% p1=10%
Device unsuccess under control after 33 cases (including pure native AR) (Previous analysis in high risk: 32 cases)
VARC-2 DEVICE SUCCESS IN INTERMEDIATE RISK PATIENTS
Intermediate risk analysis
VARC-2 EARLY SAFETY AT 30 DAYS IN INTERMEDIATE RISK PATIENTS
STABLE OUTCOME AFTER 60 cases (Previous analysis 54 cases)
Intermediate risk analysis
• Male, 82yo, admitted for repeated episodes of
syncope and overt heart failure.
• Severe symptomatic aortic stenosis
• Severe bilateral emphysematous lungs (GOLD III
stage) domiciliary O2 therapy
• Chronic Kidney disease stage III (ClCr 30ml/h)
• Severe PAD (previous aorto-iliac endo-prosthesis)
and carotid and femoral stenoses
• Severe CAD of the mid-LAD (no angina)
• Euroscore = 32.82
Case presentation: TAVI in 2011
Spirometry
VC=2.21/3.33 (66%)
FEV1=0.99/2.40 (41%)
RV=4.90/2.69 (182%)
TA approach excluded because of the severe pulmonar disease
Dia
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ram
Left Iliac Right Iliac
Rig
ht
Left
20F
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intr
od
uced
over
an
extr
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ire, b
ut
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Surgical vascular access of the left common femoral artery
23mm Novaflex
23mm Novaflex
“Valve in valve” implantation of two self-expandable trans-catheter aortic
valves to exclude aortic root aneurysm and treat massive aortic
regurgitation.
75 years old male Massive aortic insufficiency, LVEF 50% Large aneurysm of the aortic root. Two previous cardiac surgeries: CABG and plastic of the aortic valve. Aortic dissection with implantation of a Dacron tube in ascending aorta.
CT scan at level of the aneurysm of the Valsalva simus (56mm)
Dissection aortique chronique, (faux chenal indiqué par une flèche), à différents niveaux: 1-D1: arc aortique, 1-D2: aorte thoracique descendante, 1-D3: aorte abdominale, 1-D4: le site de sortie à proximité de l'artère hépatique).
First CoreValve 31mm in the ascending aorta
• Première CoreValve dessus de la valve aortique native (Angio 2a et eco 2b).
• Persistance d'important fuite aortique en raison d'un écoulement turbulent entre le CoreValve et l'anévrisme de la racine aortique (figure 2c-d).
Impianto Core2
2° valve implantation in the conventional possition
CT scan of the aortic root showing the valve in valve in correct possition.
A vascular complication despite “proficiency”
A case of iliac A-V fistula repaired with covered
stent
87 years old female Standard TAVI procedure On-site proctoring case with a visiting physician
Prostar closure
Stented sealling of the AV fistula
Conclusions
• A TF TAVI program requires a minimum of about 55 to 60 cases before obtaining optimal clinical results related to the procedure
• The baseline clinical risk is only partially related to the procedural success
• Centralization of the procedures in high-volume centers offers better outcomes and a more rapid resolution of the learning curve
• Longer proctoring periods might be of help in centers starting a TAVI program