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

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lati

ve n

um

be

r o

f fa

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s (n

)

0

Total operations

To

tal fa

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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

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Left Iliac Right Iliac

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Left

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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