Frailty Index Best at Predicting Functional Decline After TAVR

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A new frailty index is better at predicting functional decline after transcatheter aortic valve replacement (TAVR) than other established risk scores such as the EuroSCORE or Society of Thoracic Surgeons (STS) score, according to a study published online September 24, 2012, ahead of print in the European Heart Journal.

For the study, Stephan Windecker, MD, of Bern University Hospital (Bern, Switzerland), and colleagues assessed 119 patients who were at least 70 years of age and underwent TAVR at their institution from September 2009 to March 2011. Researchers collected data on baseline EuroSCORE, STS score, and calculated a frailty index that was developed by the investigators (a 0 to 7 point scale based on an assessment of cognition, mobility, nutrition, and instrumental and basic activities of daily living) to predict functional decline.

Frailty More Predictive than Established Parameters

Functional decline, defined as deterioration in the ability to perform basic activities of daily living, was observed in 22 (20.8%) patients at 6 months; 13 (10.9%) patients died. Both EuroSCORE (OR per 10% increase 1.18; 95% CI 0.83-1.68; P = 0.35) and STS Score (OR per 5% increase 1.64; 95% CI 0.87-3.09; P = 0.13) were poor predictors of functional decline. However, the frailty index was a strong predictor in both univariable (OR per 1 point increase 1.57; 95% CI 1.20-2.05; P = 0.001) and bivariable analyses (OR 1.56; 95% CI 1.20-2.04; P = 0.001 controlled for EuroSCORE; OR 1.53; 95% CI 1.17-2.02; P = 0.002 controlled for STS Score).

Overall predictive performance was best for the frailty index (0.135) and low for both EuroSCORE (0.015) and STS Score (0.034). In univariable analysis, all components of the frailty index contributed to the prediction of functional decline.

At baseline, NYHA class III or IV was present in 53.8% of patients while at 6-month follow-up, this proportion decreased to 15.1%. The proportion of patients with functional decline who had NYHA class III or IV at 6-month follow-up (22.7%) was not greater than that of patients without functional decline (13.1%; P = 0.261).

More Emphasis on Functional Status

“This study adds to growing evidence that geriatric measures of functional status are important outcomes in elderly patients,” the authors write, adding that “these measures identify patients with diminished physiological reserves in multiple organ systems and therefore have the potential to differentiate between patients with the potential to recover and those at risk to deteriorate after an intervention.”

Since frailty is still a “novel concept in geriatrics,” they continue, a generally accepted definition of the term is still lacking. The authors say the index used in the study is enhanced because it is the first to include a measure of cognitive function, but additional research is needed to confirm the index’s validity before routine use in clinical practice.

Ultimately, “early identification of patients at increased risk of functional decline is clinically relevant, because these patients might benefit from interventions designed to maintain or improve functional status,” they write.

Seeking Uniform Methodology

In a telephone interview with TCTMD, Josep Rodés-Cabau, MD, of the Quebec Heart and Lung Institute (Quebec City, Canada), said the study represents a step in the right direction. “It adds new data on the importance of evaluating elderly patients undergoing [TAVR],” he said. “In the future, we will not only have to identify the patients who [will] survive the procedure, but the patients who [will] survive with improvement.”

Still, “there is no doubt that this frailty index will have to be evaluated with a much larger number of patients before implementing into clinical practice,” Dr. Rodés-Cabau emphasized.

Ted Feldman, MD, of Evanston Hospital (Evanston, IL), told TCTMD in a telephone interview that the study adds to the “ever-growing process of understanding how to quantify frailty.” Even though the importance of doing so is obvious, he said, it remain unclear which indices are best.

“We as a community have to figure out a uniform approach or this will turn into a very challenging problem of which indices to use and which are most meaningful,” Dr. Feldman continued. “Hopefully, we’ll have multi-society collaboration to tackle this problem.”

Study Details

Mean age was 83.4 ± 4.6 years and more than half of the study participants were women. As patients with low risk scores were advised to undergo surgery over TAVR, the mean logistic EuroSCORE was high (25.3 ± 14.2%) and comorbidities, such as CAD, were present in the majority of patients. About half of patients were considered frail at baseline.

 

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Source:
Schoenenberger AW, Stortecky S, Neumann S, et al. Predictors of functional decline in elderly patients undergoing transcatheter aortic valve implantation (TAVI). Eur Heart J. 2012;Epub ahead of print.

 

 

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