Real-time Three-dimensional Echocardiography Evaluation Of The Left Ventricular Fuction In Patients With Unstable Angina Before And After Stent Implantation

Objective:To assess the change of left ventricular function and synchrony in patients with unstable angina(UA) before and after coronary artery stent implantation by real-time three-dimensional echocardiography(RT-3DE) and to provide a accurate, new technique for analyzing condition and assessing effect. Methods:One hundred patients with UA who were proved to exist only one severely stenosal(?75%) epicardial coronary artery and underwent stenting in Affiliated Hospital of Jining Medical University were included into the case group. These UA patients were divided into three subgroups: left anterior descending artery group(LAD group), left circumflex artery group(LCX group) and right coronary artery group(RCA group). The case group was examined by RT-3DE before and one month after coronary artery stent implantation. Meanwhile, forty healthy people whose coronary artery were stenosal(<50%) were collected as the control group.RT-3DE was performed for all subjects using a IE33 Elite ultrasound machine(Phillips company) with a X5-1 probe. Then the Qlab 9.1 software provided the 17 segmens' volume-time curves(VTCs), the illustration of the bull's eye and some related parameters. Thereinto, the global function parameters include left ventricular global end-diastolic volume(gEDV), global end-systolic volume(gESV), global ejection fraction(gEF), normalized values of peak ejection rate(PER/gEDV) and peak filling rate(PFR/gEDV, PFR/PER). The segmental function parameters include regional end-diastolic volume(rEDV), regional end-systolic volume(rESV) and regional ejection fraction(rEF). The synchronic parameters are the maximal difference and standard deviation of the time taken to reach the minimal systolic volume for sixteen segments(Tmsv16-Dif, Tmsv16-SD), and their corrected values(Tmsv16-Dif%, Tmsv16-SD%), dispersion of displacement for seventeen segments(Esd/Ea). Results:1.In case group before stenting, compared with the control group, gESV, Tmsv16-Dif%, Tmsv16-SD%, Esd/Ea were larger, gEF, PER/gEDV, PFR/gEDV and PFR/PER were smaller; for the segments supplied by the severely stenosal coronary branch, all rESV and some rEDV were larger and all rEF were smaller(all P<0.05). In case group after stenting, gESV, Tmsv16-Dif%, Tmsv16-SD%, Esd/Ea, rESV and rEDV decreased, while gEF, PER/gEDV, PFR/gEDV, PFR/PER and rEF increased(all P<0.05), but most parameters still showed statistical differences with the control group(all P<0.05).2.For control group, the 17 segments' VTCs are “U-shaped”, whose amplitude are large and peak and valley are nearby; the timing illustration of the bull's eye shows homogeneous green and the excursion illustration of the bull's eye shows homogeneous blue.But for case group, before stenting, the amplitude of the segments supplied by severely stenosal coronary branch is small and their valley is backward, so that the 17 segments' VTCs are irregular; after stenting, their amplitude become large and valley move forward, so the 17 segments' VTCs become more regular than pre-stenting. For case group, before stenting, the illustration of the bull's eye showed red and black in those ischemic segments; after stenting, the area of red and black lessened. Conclusion:1.The RT-3DE 17 segmets' VTCs and illustration of the bull's eye can intuitively display the ischemic segments when severely stenosal coronary artery exists,according to which, the severely stenosal coronary artery and the change of fuction brought by stenting can be recognized.2.Stent implantation can improve the left ventricular function and synchrony in patients with UA and RT-3DE can accurately quantify the improvement, which can be applied as a noninvasive method for evaluating the patients' condition befor stenting and the effect of stenting.