Clinical Significance of Ejection Dynamics Parameters in Patients with Aortic Stenosis: An Outcome Study
Résumé
Background: Ejection dynamics parameters are useful in assessing prosthetic valve obstruction, but very limited data are available in the setting of native aortic stenosis (AS). The aim of this study was to evaluate and compare the prognostic value of acceleration time (AT) and the ratio of AT to ejection time (ET) in patients with AS. Methods: AT and AT/ET were prospectively measured in 456 patients with AS (aortic valve area < 1.3 cm 2; mean aortic valve area, 0.85 +/- 0.24 cm 2). The relationships between AT/ET, AT, and mortality during follow-up were studied. Results: During a median follow-up period of 35 months (interquartile range, 33-37 months), 124 patients died. After adjustment for variables of prognostic importance, including mean pressure gradient, stroke volume index, and aortic valve replacement as a time-dependent covariate, patients in the highest tertiles of both AT/ET (>0.36) and AT (>112 msec) were at high risk for overall mortality (adjusted hazard ratios, 2.44 [95% CI, 1.46-4.08; P = .001] and 1.78 [95% CI, 1.06-2.98; P = .029], respectively) compared with those in the lowest tertiles of AT/ET and AT, while survival was similar for the other tertiles (P = NS for all). Compared with patients with AT/ET <= 0.36, an increased risk for overall mortality was observed in patients with AT/ET > 0.36 (adjusted hazard ratio, 2.51; 95% CI, 1.66-3.78; P < .0001), while the risk for mortality was not significantly increased in patients with AT > 112 msec compared with those with AT <= 112 msec. Adding AT/ET > 0.36 to a multivariate model including classical variables of prognostic importance, including mean pressure gradient and stroke volume index, improved predictive performance in terms of overall mortality, with improved global model fit, reclassification, and better discrimination. Conclusions: Among ejection dynamics parameters in patients with AS, AT/ET is strongly associated with excess risk for death during follow-up. AT/ET should be considered in the multiparametric echocardiographic prognostic assessment of patients with AS in clinical practice.