Value of blood flow vector imaging in quantitative observation of left ventricular hemodynamics in patients with aortic stenosis

  AIM  To investigate the value of flow vector imaging (VFM) in observing left ventricular hemodynamics in patients with aortic valve stenosis (AS).

  METHODS  A total of 166 AS patients admitted to our hospital from July 2018 to July 2020 were selected for this study. According to MTPG, the patients were divided into group A (mild stenosis: MTPG < 30mmHg, 1mmHg = 0.133kpa, n = 62), group B moderate stenosis: MTPG(30 ~ 50)mmHg, n = 55 and group C (severe stenosis: MTPG > 50mmHg, n = 49). In addition, 166 healthy volunteers in our hospital were selected as control group. Both patients and volunteers received routine echocardiography and VFM image processing after admission. Conventional echocardiographic indicators of the four groups were compared, including left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and ratio of peak mitral valve velocity in early diastolic phase to peak mitral valve velocity in atrial systolic phase (E/A). Peak systolic flow rates (Fs), negative total systolic flow rates (SQ) and peak systolic flow rates (Vs) were recorded and compared in the basal segment, middle segment and apex segment during rapid ejection period. Finally, Pearson correlation analysis was used to analyze the correlation between the ultrasonic examination indexes (LVEF, E/A) and VFM image processing indexes (FS, SQ, Vs).

  RESULTS  There was no significant difference in LVEDD, LVEDV and LVESV levels between the four groups. Statistically significant differences were found in LVEF and E/A between the 4 groups (control group > group A, B and C, P < 0.01) and statistically significant differences were found in the levels of Fs, SQ and Vs in the basal segment, the middle segment and the apex segment (control group > group A > group B > group C, P < 0.05). According to correlation analysis, ultrasound examination indexes LVEF and E/A showed positive correlation with Fs, SQ and Vs in the left ventricle during rapid ejection period (all, P < 0.01).

  CONCLUSION  VFM effectively observes the changes of left ventricular hemodynamics in AS patients, which is conducive to the clinical diagnosis and treatment, and is worthy of clinicians’ attention.