Predictive value of five risk scores to predict outcomes after aortic valve replacement in octogenarians

Operative risk is assessed preoperatively through the use of predictive scores. The study aim was to evaluate the validity of five different scoring systems, including the Society of Thoracic Surgeons (STS) score, additive and logistic European systems (EuroSCORE 1) for cardiac operative risk evaluation, EuroSCORE 2, and the Ambler score in octogenarian patients undergoing aortic valve replacement (AVR).

A total of 225 patients aged > or = 80 years with aortic stenosis underwent isolated AVR between January 1996 and September 2010. All five scores were evaluated with regards to their accuracy in predicting operative mortality, mortality at one year, and the capacity to identify those patients most likely to die during long-term follow up.

The observed operative mortality rate was 7.6%. The observed/expected ratios calculated for perioperative mortality were 0.42, 0.87, 1.16 and 1.16 for the logistic EuroSCORE, Ambler score, STS score and EuroSCORE 2 cohorts, respectively. The Hosmer-Lemeshow statistical test showed that all five scores were well calibrated. The STS score was a good test for predicting operative mortality (AUC 0.81) and the EuroSCORE 2 was fair (AUC 0.72). In terms of predicting the one-year mortality rate, the STS score was ranked as fair (AUC > 0.7). It was noted that patients with a STS score > or = 75th percentile were more likely to die during the follow up period.

The STS score appeared to be more adequate for predicting operative mortality among patients aged > or = 80 years. STS scores were predictive of both one-year and long-term survival rates. These results indicated that the STS score could be used to guide clinical decision-making for performing AVR in elderly patients.