Researchers identified predictors of 30-day and one-year mortality in patients who have undergone transcatheter aortic valve replacement (TAVR) and developed a scoring system that may help forecast mortality following TAVR.

Lead author James B. Hermiller, Jr., MD, of Saint Vincent’s Heart Center of Indiana in Indianapolis, and colleagues published their results online in the Journal of the American College of Cardiology on July 18.

They evaluated 3,687 patients who enrolled in Medtronic’s CoreValve U.S. pivotal trial and were considered to be at extreme risk or high risk for surgical aortic valve replacement. The patients were treated with the CoreValve self-expanding TAVR system with 23-, 26-, 29- and 31-mm diameter valves.

The mean age of patients was 83.3 years old and 46.3 percent were women. At baseline, the mean STS PROM (Society for Thoracic Surgery Predictive Risk of Mortality) score was 8.9 and the mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) score was 22.2.

The researchers found that the following variables were significant independent predictors of 30-day mortality following TAVR: home oxygen use, residence in an assisted living facility, an albumin level less than 3.3 g/dl and age greater than 85 years old.

Based on those results, they created a scoring system that included home oxygen use (two points), albumin level less than 3.3 mg/dl (two points), assisted living (two points) and age older than 85 (one point). Patients were considered at low risk if they had a score of zero, moderate risk if they had a score of one or two and high risk if they had a score from three to seven. The 30-day mortality rates were 3.6 percent for the low risk group and 10.9 percent for the high risk group.

In addition, the following variables were significant independent predictors of one-year mortality: home oxygen use, albumin level less than 3.3 g/dl, falls in the past six months, high Charlson comorbidity score and STS PROM greater than 7 percent.

The researchers then created a scoring system and found that the one-year mortality rates were 12.3 percent for the low risk group and 36.6 percent for the high risk group.

The study had a few limitations, according to the researchers, including its retrospective post hoc design. They added that the predictive model might not apply to moderate risk or low risk patients. In addition, they said that the scoring system might not be practical if information on baseline frailties and disabilities were not available.

Still, they mentioned that previous research found STS PROM was not effective as assessing risk following TAVR. They believe their score could serve as a complement to guidelines and other sources to determine which patients are at risk following the procedure.

“Conventional risk score algorithms, such as that of STS-PROM used to predict mortality after aortic valve replacement, were supplemented by objective measures of comorbidity, frailty, and disability,” the researchers wrote. “Our simple score dominated by novel predictors of outcome effectively stratified early and late mortality in extreme-risk and high-risk patients and may assist in selecting those patients appropriate for TAVR.”