Does indexing aortic valve area by body surface area improve the predictive accuracy for aortic valve events in patients with aortic stenosis compared to unindexed aortic valve area?
Indexing aortic valve area by body surface area increases the diagnosis of severe aortic stenosis by including milder cases, but does not improve predictive accuracy for clinical events.
BACKGROUND: To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are 2.5 m/s) and from 1525 patients prospectively followed in the simvastatin and ezetimibe in aortic stenosis (SEAS) trial were analysed. RESULTS: The prevalence of severe stenosis increased with the AVAindex criterion compared to AVA from 71% to 80% in the retrospective cohort, and from 29% to 44% in SEAS (both p<0.001). Overall, the predictive accuracy for aortic valve events was virtually identical for AVA and AVAindex in the SEAS population (mean follow-up of 46 months; area under the receiver operating characteristic curve: 0.67 (95% CI 0.64 to 0.70) vs. 0.68 (CI 0.65 to 0.71) (NS). However, 213 patients additionally categorised as severe by AVAindex experienced significantly less valve related events than those fulfilling only the AVA criterion (p<0.001). CONCLUSIONS: Indexing AVA by BSA (AVAindex) significantly increases the prevalence of patients with criteria for severe stenosis by including patients with a milder degree of the disease without improving the predictive accuracy for aortic valve related events.
Jander et al. (Thu,) studied this question.