Relevance of using the right parasternal projection in ultrasound assessing the severity of aortic stenosis. Results of a single-center prospective study

Objective. To evaluate the effectiveness of using the right parasternal view (RPV) in addition to the apical five-chamber view (A5CV) for assessing the severity of aortic stenosis (AS) and to identify factors influencing the concordance of AS severity assessment between RPV and A5CV. Materials and Methods . During the patient recruitment period, 232 patients were consecutively examined, and 186 (80%) patients with an available RPV were included in the final analysis. Inclusion criteria: Patients with AS (combination of a calcified aortic valve and a peak transaortic velocity >2.5 m/s) and an available RPV for AS severity assessment. Results. The average Gmax and Gmean values assessed in RPV were significantly higher, and the average AVA and DVI values were lower compared to similar values assessed in the A5СV, p <0.05. Bland-Altman analysis showed that the mean differences in Gmax and Gmean between A5CV and RPV were 10.2±14.3 mmHg and 4.5±8.9 mmHg, respectively. The mean differences in AVA and DVI between A5CV and RPV were 0.1±0.15 cm 2 and 0.02±0.03 ml, respectively. Using RPV allowed reclassification of AS severity to a more severe degree of aortic stenosis in 44 (23%) patients. Multivariate logistic regression analysis identified the aorto-septal angle as the only independent parameter significantly affecting the concordance of AS severity assessment between the two acoustic projections (OR 0.76; 95% CI 0.69-0.83, p <0.001). Conclusion. 1. The use of A5CV alone may lead to an underestimation of AS severity in a significant proportion of cases. Assessing the severity of aortic stenosis in the RPV in addition to the A5СV can significantly increase the diagnostic accuracy of echocardiography. 2.The aorto-septal angle is an independent factor significantly influencing the concordance of AS severity assessment between the two echocardiographic views.