Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website http://www.cardiologyres.org

Review

Volume 10, Number 6, December 2019, pages 323-330

Risk Stratification for Transcatheter Aortic Valve Replacement

**Table 1.** Advantages of Risk Prediction Models
TAVR: transcatheter aortic valve replacement.
Decision-making tool in valvular intervention to allow optimal operative decision making.
Predict outcomes including operative mortality, stroke, and renal failure in patients undergoing valve replacement.
Allow fair comparison of operative outcomes as they control for heterogeneous patient population, disease severity and clinical comorbidities.
Predict high-risk patients and allow selection of patients for transcatheter vs. surgical aortic valve replacement.
Derived from large-scale clinical databases to predict outcomes.
Serve as a valuable resource for quality improvement, clinical decision making, and patient counseling.
Addition of new variable such as prior cardiac intervention, in-hospital stroke and frailty improves prediction in high-risk patients to optimize selection of patients for TAVR.

Table 1. Advantages of Risk Prediction Models

TAVR: transcatheter aortic valve replacement.

Decision-making tool in valvular intervention to allow optimal operative decision making.

Predict outcomes including operative mortality, stroke, and renal failure in patients undergoing valve replacement.

Allow fair comparison of operative outcomes as they control for heterogeneous patient population, disease severity and clinical comorbidities.

Predict high-risk patients and allow selection of patients for transcatheter vs. surgical aortic valve replacement.

Derived from large-scale clinical databases to predict outcomes.

Serve as a valuable resource for quality improvement, clinical decision making, and patient counseling.

Addition of new variable such as prior cardiac intervention, in-hospital stroke and frailty improves prediction in high-risk patients to optimize selection of patients for TAVR.

**Table 2.** Limitations of Risk Prediction Models
Most accurate in the population and time frame from which they are derived.
Model calibration can be lost over time leading to mis-estimation of operative outcomes, necessitating the need for periodic recalibrations.
Model derived from patients with a particular disease or procedure may not apply to another disease or procedure.
Accuracy is lost at extremes of population, i.e., very low-risk and very high-risk patients.
May not have all relevant parameters of “risk” or “severity” due to missing data in derivative population.

Table 2. Limitations of Risk Prediction Models

Most accurate in the population and time frame from which they are derived.

Model calibration can be lost over time leading to mis-estimation of operative outcomes, necessitating the need for periodic recalibrations.

Model derived from patients with a particular disease or procedure may not apply to another disease or procedure.

Accuracy is lost at extremes of population, i.e., very low-risk and very high-risk patients.

May not have all relevant parameters of “risk” or “severity” due to missing data in derivative population.

**Table 3.** Summary of Commonly Used Risk Prediction Models for Aortic Valve Intervention (Advantages and Disadvantages of Risk Assessment Models)
Risk model	Year score created	Number of patients	Country	Advantage	Disadvantage
EuroSCORE: European system for cardiac operative risk evaluation; STS-PROM: Society of Thoracic Surgeons Predicted Risk of Mortality STS: Society of Thoracic Surgeons; ACC: American College of Cardiology; TAVR: transcatheter aortic valve replacement; SAVR: surgical aortic valve replacement.
EuroSCORE	1995	19,030	128 centers from 8 European countries	Simple bedside tool to calculate mortality	Overestimates mortality at low score and underestimates at higher score
EuroSCORE II	2010	22,000	154 hospitals in 43 countries	Comprehensive model using multiple covariates for assessing mortality	Overestimates mortality at higher risk. Predicts only short-term mortality.
STS-PROM	2002 - 2006	24,222	USA	Highly predictive of short-term and long-term mortality	Developed for conventional surgical aortic valve replacement.
Edwards et al (STS/ACC TAVR score)	2016	13,718	USA	Predicts only in-hospital mortality for patients undergoing TAVR	Lacks long-term outcomes.
German aortic valve score	2008	11,974	Germany	Comparison of predicted and observed mortality for SAVR vs. TAVR in all categories of risk groups	TAVR or SAVR were not tested as an independent risk factor. Low number of TAVR procedures included.

Table 3. Summary of Commonly Used Risk Prediction Models for Aortic Valve Intervention (Advantages and Disadvantages of Risk Assessment Models)

Risk model

Year score created

Number of patients

Country

Advantage

Disadvantage

EuroSCORE: European system for cardiac operative risk evaluation; STS-PROM: Society of Thoracic Surgeons Predicted Risk of Mortality STS: Society of Thoracic Surgeons; ACC: American College of Cardiology; TAVR: transcatheter aortic valve replacement; SAVR: surgical aortic valve replacement.

EuroSCORE

1995

19,030

128 centers from 8 European countries

Simple bedside tool to calculate mortality

Overestimates mortality at low score and underestimates at higher score

EuroSCORE II

2010

22,000

154 hospitals in 43 countries

Comprehensive model using multiple covariates for assessing mortality

Overestimates mortality at higher risk. Predicts only short-term mortality.

STS-PROM

2002 - 2006

24,222

USA

Highly predictive of short-term and long-term mortality

Developed for conventional surgical aortic valve replacement.

Edwards et al (STS/ACC TAVR score)

2016

13,718

USA

Predicts only in-hospital mortality for patients undergoing TAVR

Lacks long-term outcomes.

German aortic valve score

2008

11,974

Germany

Comparison of predicted and observed mortality for SAVR vs. TAVR in all categories of risk groups

TAVR or SAVR were not tested as an independent risk factor. Low number of TAVR procedures included.