Additive value of the right parasternal view for the assessment of aortic stenosis

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 with the use of the right parasternal view (RPV) method to evaluate AS severity and to examine the diagnostic significance of performing the RPV method in addition to the apical method during the evaluation.

This retrospective observational study included 276 consecutive patients (mean age: 79 ± 10 years; women, 56%) with severe AS (aortic valve area [AVA] ≤1.0cm² ). The severity of AS according to the apical method and that according to the RPV for all subjects were compared, and the significance of performing the RPV method in addition to the apical method was examined. Furthermore, we compared the concordance group, in which the apical and RPV methods indicated matching in severity, and the discordant group, in which the apical and RPV methods did not indicate matching severity.

Peak velocity (V_max ), mean pressure gradient (MG) were significantly higher and the AVA, AVAi, and Doppler velocity index (DVI) were significantly smaller when the RPV was added to the apical view. Performing the RPV method in addition to the apical method significantly decreased the number of low PG AS cases (MG < 40 mmHg) from 69.9% to 65.0% and it increased the number of very severe AS cases (V_max ≥ 5 m/s) from 8.7% to 14.5%. Deviation of Doppler angle was significantly greater in the discordant group compared to the concordant group (22.5 ± .6 vs. 31.8 ± 1.7, p < .001).

By performing the RPV method in addition to the apical method to determine AS severity, the diagnosis of AS to be resolved in approximately 10% of cases. These results suggest that AS severity may be underestimated by using the apical method alone.