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The report by Lancellotti et al. (1) concludes that “the use of the new proposed aortic stenosis grading classification integrating valve area and flow-gradient patterns allows a better characterization of the clinical outcome of patients with asymptomatic severe aortic stenosis.” However, there are several points to be interpreted with caution before applying this conclusion to patients.
First, after the multivariate analysis, the investigators stated in the text that peak aortic velocity (in meters per second) was independently associated with event-free survival (hazard ratio [HR]: 1.7; 95% confidence interval [CI]: 1.04 to 2.84; p = 0.035). In Table 4 (1), they report a different value (HR: 1.82; 95% CI: 1.13 to 2.9; p = 0.013). However, the interpretation is similar: peak aortic velocity is a risk factor for the development of events during follow-up, with higher risk at higher velocities. The investigators also found that the new proposed category of low flow/low gradient was an independent predictor (in the text : HR: 5.26; 95% CI: 2.04 to 14.3; p = 0.045; in Table 4 : HR: 5.22; 95% CI: 2.02 to 14.1; p = 0.001). Discordant data between the text and the table are also presented for the category of low flow/high gradient. The low gradient variable alone was also an independent predictor (HR: 2.4; 95% CI: 1.4 to 4.2; p = 0.003), as was the variable in its continuous format (mean pressure gradient). Peak aortic velocity and mean aortic gradient are closely and directly correlated. Therefore, is difficult to conclude that those variables predict events in a contradictory fashion in the same patients.
Second, as the investigators cited as study limitations, there were just 11 patients in the category with worse evolution (low flow/low gradient) and 15 in the category of low flow/high gradient. Only a few events explained the very different evolution in both categories. Chance may explain these results.
Third, under “Clinical Implications,” Lancellotti et al. (1) stated that “early elective aortic valve replacement could represent a beneficial option in those with low comorbidities,” citing a report by Kang et al. (2). However, this study evaluated patients with “asymptomatic very severe aortic stenosis,” and mean aortic gradients were 59 and 65 mm Hg in the 2 groups of patients, so the results are not applicable to low-flow/low-gradient patients.
Finally, I agree with Flachskampf and Kavianipour (3) that “the first reflex in the presence of a surprising ‘paradoxic’ set of echo data should be critical review of the raw data.” I think that more data are needed before adopting as an everyday practice this new classification.
- American College of Cardiology Foundation
- Lancellotti P.,
- Magne J.,
- Donal E.,
- et al.
- Kang D.H.,
- Park S.J.,
- Rim J.H.,
- et al.
- Flachskampf F.A.,
- Kavianipour M.