Velocity-Time Integral of Aortic Regurgitation: A Novel Echocardiographic Marker in the Evaluation of Aortic Regurgitation Severity

Background: Echocardiography is essential for the diagnosis and quantification of aortic regurgitation (AR). Velocity-time integral (VTI) of AR flow could be related to AR severity. Objective: This study aims to assess whether VTI is an echocardiographic marker of AR severity. Methods: We included all patients with moderate or severe native AR and sinus rhythm who visited our imaging laboratory from January to October 2016. All individuals underwent a complete echocardiogram with AR VTI measurement. The association between VTI and AR severity was analyzed by logistic regression and multivariate regression models. A p-value<0,05 was considered statistically significant. Results: Among the 62 patients included (68.5 +/- 14.9 years old; 64.5%: moderate AR; 35.5%: severe AR), VTI was higher in individuals with moderate AR compared to those with severe AR (2.2 +/- 0.5 m vs. 1.9 +/- 0.5 m, p=0.01). Patients with severe AR presented greater values of left ventricular end-diastolic diameter (LVEDD) (56.1 +/- 7.1 mm vs. 47.3 +/- 9.6 mm, p=0.001), left ventricular end-diastolic volume (LVEDV) (171 +/- 36.5 mL vs. 106 +/- 46.6 mL, p<0.001), effective regurgitant orifice (0.44 +/- 0.1 cm(2) vs. 0.18 +/- 0.1 cm(2), p=0.002), and regurgitant volume (71.3 +/- 25.7 mL vs. 42.5 +/- 10.9 mL, p=0.05), as well as lower left ventricular ejection fraction (LVEF) (54.1 +/- 11.2% vs. 63.2 +/- 13.3%, p=0.012). The VTI proved to be a marker of AR severity, irrespective of LVEDD, LVEDV, and LVEF (odds ratio 0.160, p=0.032) and of heart rate and diastolic blood pressure (DBP) (odds ratio 0.232, p=0.044). Conclusions: The VTI of AR flow was inversely associated with AR severity regardless of left ventricular diameter and volume, heart rate, DBP, and LVEF. VTI could be a marker of AR severity in patients with native AR and sinus rhythm.