Additive value of the right parasternal window for the assessment of
aortic stenosis
Abstract
Background: Although Doppler evaluation using a multiplanar
method is recommended to assess the severity of aortic stenosis (AS)
with transthoracic echocardiography, evidence on the diagnostic
significance of a non-apical method is limited. This study aimed to
compare the use of the apical window (AW) with use of the right
parasternal window (RW) method to evaluate AS severity and to examine
the diagnostic significance of performing the RW method in addition to
the AW method during the evaluation. Methods: This
retrospective observational study included 287 consecutive patients
(mean age: 79 ± 10 years; women, 56%) with severe AS (aortic valve area
[AVA] ≤1.0cm 2). The severity of AS according to
the AW method and that according to the RW for all subjects were
compared, and the significance of performing the RW method in addition
to the AW method was examined. Furthermore, we compared the concordance
group, in which the AW and RW methods indicated matching in severity,
and the discordant group, in which the AW and RW methods did not
indicate matching severity. Results: Peak velocity (PV), mean
pressure gradient (PG), and AVA were not significantly different between
the AW and RW methods. Performing the RW method in addition to the AW
method significantly decreased the number of low PG AS cases (mean PG
<40 mmHg) from 71.1% to 65.0% and it increased the number of
very severe AS cases (PV ≥5m/s) from 8.7% to 14.5%. Although, there
was no significant difference in the Doppler angle (DA) observed using
the AW method for the discordant group and the concordant group, the DA
observed using the RW method was significantly smaller in the discordant
group (8.8±8.2, 16.3±12.3 °, p<0.01). In the
receiver-operating characteristic analysis, with the RW method, a DA of
8° was the cutoff value for discrepancies between the two groups.
Conclusions: By performing the RW method in addition to the AW
method to determine AS severity, different severity is observed in
approximately 10% of cases. These results suggest that AS severity may
be underestimated by using the AW method alone.