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

Abstract 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 cm2vs. 0.18±0.1 cm2, 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. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

摘要
背景 超声心动图（echocardiography）是诊断及量化评估主动脉瓣反流（aortic regurgitation, AR）的核心手段。AR血流的速度-时间积分（velocity-time integral, VTI）或与AR严重程度相关。
目的 本研究旨在评估VTI是否可作为AR严重程度的超声心动学标志物。
方法 纳入2016年1月至10月于本影像科就诊的所有窦性心律（sinus rhythm）合并中-重度原发性AR患者。所有受试者均接受完整超声心动图检查并测量AR VTI。采用logistic回归及多变量回归模型分析VTI与AR严重程度的关联，以P<0.05为差异具有统计学意义。
结果 共纳入62例患者，年龄为68.5±14.9岁；其中64.5%为中度AR，35.5%为重度AR。与重度AR患者相比，中度AR患者的VTI更高（2.2±0.5 m vs. 1.9±0.5 m，P=0.01）。重度AR患者的左心室舒张末期内径（left ventricular end-diastolic diameter, LVEDD）更高（56.1±7.1 mm vs. 47.3±9.6 mm，P=0.001）、左心室舒张末期容积（left ventricular end-diastolic volume, LVEDV）更大（171±36.5 mL vs. 106±46.6 mL，P<0.001）、有效反流口面积（effective regurgitant orifice）更大（0.44±0.1 cm² vs. 0.18±0.1 cm²，P=0.002）、反流量（regurgitant volume）更高（71.3±25.7 mL vs. 42.5±10.9 mL，P=0.05），而左心室射血分数（left ventricular ejection fraction, LVEF）更低（54.1±11.2% vs. 63.2±13.3%，P=0.012）。校正LVEDD、LVEDV及LVEF后，VTI仍可作为AR严重程度的标志物（比值比0.160，P=0.032）；进一步校正心率及舒张压（diastolic blood pressure, DBP）后，该关联依然显著（比值比0.232，P=0.044）。
结论 AR血流的VTI与AR严重程度呈负相关，且不受左心室内径、容积、心率、DBP及LVEF的影响。VTI可作为窦性心律合并原发性AR患者的AR严重程度标志物。(Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)