Identification of Factors that Predict whether the Right Parasternal View Is Required for Accurate Evaluation of Aortic Stenosis Severity

BACKGROUND: To accurately assess aortic stenosis (AS) severity, multiple windows should be used to best align the Doppler beam with the flow direction of the stenotic jet. To evaluate: (1) the frequency at which the highest peak AV velocity is found in the right parasternal window (RPW), (2) the extent of correlation between aortic root angulation and the location of the highest peak AV jet velocity, and (3) which patients would benefit most from RPW-based assessment of AS severity. METHODS: We evaluated AS velocity in the apical window (AW) and RPW by continuous-wave Doppler (CWD) in 263 patients with more than moderate AS. If the AV was inaccessible by the left parasternal long-axis view, the aortoseptal angle was measured by echocardiography and a sagittal view of a computed tomography (CT). RESULTS: Patients were divided into two groups, the RPW group and the AW group. Significant differences were observed between the two groups regarding the sinus of Valsalva diameter, the aortoseptal angle as measured by echocardiography, and the type of valve. The aortoseptal angle as measured by echocardiography was larger in the AW group compared with the RPW group. Aortoseptal angle (P < 0.001) and valve type (P = 0.036) were independent predictors that the highest AV Vmax would be obtained from the RPW. CONCLUSIONS: The right parasternal window must be evaluated to achieve the most accurate assessment of AS severity, especially in patients with an aortoseptal angle <119° in the parasternal long-axis view as measured by echocardiography.