The Stress-Recovery Index for the risk stratification of women with typical chest pain

Aim: To prospectively assess the prognostic value of the Stress-Recovery Index (SRI) in women with typical chest pain. Methods: 165 women without known coronary artery disease, who complained of typical chest pain, were exercise tested and prospectively followed-up for the occurrence of cardiac death and nonfatal myocardial infarction. SRI, defined as the difference in absolute values between the area of heart rate-adjusted ST-segment depression during exercise and recovery, was derived in all. Clinical data, resting ejection fraction, and exercise testing data were entered into a sequential Cox's model; SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival curves were set up using Kaplan-Meier method and compared by the log-rank test. Results: During a median follow-up time of 42 months, 19 events (14 cardiac deaths and 5 nonfatal myocardial infarction) were observed. Age (hazard ratio 3.58, 95% CI 0.87-15) and SRI (hazard ratio 0.62, 95% CI 0.42-0.92) were multivariate predictors of outcome. However, the addition of SRI increased the prognostic power of the model on top of clinical and exercise testing variables, as demonstrated by the significant (p = 0.003) increase of the area under the ROC curve of the risk function. Survival analysis showed ascending SRI quartiles to identify a significant (p = 0.005) increase in event-free survival. Conclusions: SRI is of value in predicting outcome of women with typical chest pain and provides additional prognostic information on the top of clinical and standard exercise testing data.