The usage of combined risk models of frailty and conventional risk scores significantly enhances prediction of one-year mortality in patients undergoing TAVR, according to a recent publication in the Journal of American College of Cardiology.
Prior to the study, risk stratification of patients before TAVR was performed using conventional models such as the Society of Thoracic Surgeons (STS) score and the European System for Cardiac Operative Risk Evaluation (EuroSCORE), which were deemed incomplete and not precise enough for TAVR. In order to address this, the principal investigator, Dr. Schoenenberger, and his colleagues aimed to identify whether the prediction of 1-year mortality after TAVR was improved with the use of a frailty score based on multidimensional geriatric assessment (MGA), in combination with conventional risk scores.
A prospective cohort study was conducted on 330 TAVR patients who are 70 years of age or older. In order to predict 1 year all-cause mortality of the patients, the frailty score including the assessment of cognition using Mini-Mental State Exam (MMSE), gait function using the Timed Up and Go test (TUG), nutrition using Mini Nutritional Assessment (MNA) and activities of daily living (ADLs) was used, along with conventional risk scores.
“None of the previous studies proved that risk prediction of the conventional risk scores (STS score or EuroSCORE) is truly improved in combined prediction models.”
The investigators found that while all risk scores are predictive of the outcome, a combination of frailty index with either EuroSCORE or STS score significantly improved prediction of mortality. Moreover, the contribution of the frailty index was 77.6% and 58.2% of the predictive information of the combined score using STS score and EuroSCORE respectively. Amongst the individual components of the frailty index, the Timed Up and Go test TUG showed the best prediction of 1-year mortality, followed by MMSE and MNA. This highlighted the fact that “mobility impairment is extremely important for the prediction of adverse outcomes.”
Schoenenberger et al proved that ‘1- year mortality gradually increased with increasing frailty’, with mortality rates in the highest 2 frailty categories exceeding 50%. As a result, the frailty index could be helpful in triaging patients under evaluation for TAVR and in recommending palliative therapy to patients at high-risk. Due to this, assessment of frailty using mobility, cognition, nutrition, and disability could help in the improvement of therapeutic decisions. The authors stressed that “None of the previous studies proved that risk prediction of the conventional risk scores (STS score or EuroSCORE) is truly improved in combined prediction models.”
Lastly, the investigators acknowledged certain limitations by saying that the study was restricted to a single center and included only high-risk, elderly patients. The patients with high frailty index were less in number and patients were treated with first-generation devices. While there remains a need for multicenter trials to develop better prediction models, Dr. Schoenenberger recommended that frailty evaluation based on MGA should be part of every clinical evaluation of TAVR patients, as an aid to improved clinical decision making. In order to implement this, experienced geriatricians should be a part of heart teams in the assessment of high-risk TAVR patients.
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