Evaluation Of Left Ventricular Long-axis Function During Coronary Artery Bypass Graft Using Real-time Tri-plane Strain Rate Imaging

PART ONEEvaluation of Left Ventricular Long-axis Function During Coronary Artery Bypass Graft Using Real-time Tri-plane Strain Rate ImagingBackgroundOff-pump coronary artery bypass graft (OPCABG) is an important treatment for patients with coronary artery disease. Thus it is very important to evaluate the LV function accurately before and after OPCABG. Strain rate imaging (SRI) describes myocardial deformation rather than velocity and displacement, could be a more specific technique for the assessment of regional myocardial function and therefore superior to tissue doppler imaging. Much research has found that SRI is an effective quantitative method for evaluation of myocardial deformation. However, SRI measures deformation in only one plane. Real-time tri-plane echocardiography can show3planes in the same R-R interval. Combined Real-time tri-plane technology and SRI can measure the each segment of the left ventricular in the same R-R interval. Real-time tri-plane SRI avoids the effects of different cardiac cycle variation on different wall segment of the LV. The aim of this study was to evaluate the capability of real-time tri-plane SRI for monitoring left ventricular long-axis systolic function before and after OPCABG and for evaluating the effect of surgery.Objective:To evaluate the left ventricular long-axis systolic function before and after OPCABG using real-time tri-plane strain rate imaging.MethodsWe recruited30healthy volunteers as control group and30patients with coronary artery disease who were treated by OPCABG. In this study, an apical4-chamber view was chosen as the primary image plane. The matrix array transducer then allowed the visualization of4-chamber,2-chamber, and long-axis apical views simultaneously. Echocardiographic data were acquired before OPCABG and a week and3months after OPCABG. The sample was located in the basal, middle and apical segments of interventricular septum and left ventricular wall. The systolic strain rate (SRs) and post systolic shortening (PSS) were measured.ResultsCompared with control group, SRs was lower in OPCABG group. SRs was increased at a week after OPCABG, and further increased at3month after OPCABG. PSS were emerged in27segments before OPCABG, and decreased a week after OPCABG and further decreased3months after OPCABG (P<0.05). Compared with control group, MSRs was lower in OPCABG group, and increased gradually after OPCABG. Absolute value of MSRs was related to LVEF (r=0.68, P<0.01).ConclusionsLeft ventricular long-axis systolic function was decreased in patients with coronary artery disease and gradually improved after OPCABG. Real-time tri-plane strain rate imaging can quantitative evaluate left ventricular long-axis systolic function before and after OPCABG. PART TWOStudy on Left Ventricular Rotation and Twist by Two-Dimensional Speckle Tracking Imaging in Patients with Coronary Artery DiseaseBackgroundMany studies confirmed that the left ventricular twist and untwist are very important for left ventricular systolic ejection and diastolic blood filling. Assessment left ventricular twist and untwist can providing myocardial local and global information. Later, some investigators showed that LV rotation and twist could be measured by speckle tracking imaging (STI). This study aids to assessment of left ventricular rotation and twist by using STI in patients with coronary artery disease.ObjectiveEvaluation left ventricular rotation and twist in patients with coronary artery disease by two-dimensional speckle tracking imaging.Mehods70patients diagnosed coronary artery disease (CAD) were included in the study and30healthy volunteers as control group. Short-axis parasternal views were taken at the base and the apex of the heart. Using the two-dimensional speckle tracking imaging, we analysed the rotation curves at apex and base, and measured endo-radius global rotation (Rendo), epi-radius global rotation (Repi), bulk rotation (Rbulk) and the mural torsion (Tmural). We calculated the LV twist. LV twist was defined as the net difference (in degree) of the apical and basal rotation. Then we measured the peak subendocardial globe LV twist (Ptw-endo), peak subepicardial globe LV twist (Ptw-epi), peak globe LV twist (Ptw-bulk) and mural twist (Ptw-mural). We recorded the time to peak, and calculated the untwist rate (UntwR) and Ptw-UntwR also.ResultsThere were significant differences in LV rotation and twist between CAD and control group (P<0.05). Compared with control group, the Rendo, Repi, Rbulk, Tmural, Ptw-endo, Ptw-epi, Ptw-bulk and Ptw-mural were decreased, the time to peak were delayed, the UntwR and Ptw-UntwR was decreased, respectively (P<0.01). According to the Gensini score, we divided the patients into3groups (A, B and C). Compared with control group, the Ptw-endo was decreased (P<0.01) in group A, there was no difference in Ptw-epi. The Ptw-endo, Ptw-epi, Ptw-bulk and Ptw-mural were decreased in group B and further decreased in group C, respectively (P<0.01). Rendo, Repi, Rbulk, Tmural and UntwR decreased significantly in apical level in patients with anterior descending branch stenosis (P<0.01), and decreased significantly in basal level in patients with right coronary artery stenosis (P<0.01). Rendo, Repi, Rbulk, Ptw-endo, Ptw-epi and Ptw-bulk were significantly related to LVEF in overall population. Ptw-endo, Ptw-epi, Ptw-bulk positively correlated with LVEDV (P<0.05), negative correlated with LVESV and SBP in control group (P<0.05). There was no correlation between Ptw-endo, Ptw-epi, Ptw-bulk and LVEDV, LVESV, SBP in CAD group. However, Rendo、Repi、Rbulk、Ptw-endo、Ptw-epi and Ptw-bulk were significantly related to Gensini score in CAD group. UntwR and Ptw-UntwR were not related to E/A and EDT.ConclusionsLV rotational mechanics is affected differently in the subendocardial and subepicardial layers in patients with coronary artery disease. The rotation of subendocardial is reduced in patients with mild coronary artery stenosis, whereas subendocardial, subepicardial and LV twist was reduced in patients with more servece coronary artery stenosis. Left ventricular untwist rate was significantly reduced in CAD. Different coronary atery stenosis affect differently in basal and apex level. LV twist is related to LVEF. STI can evaluate LV twist accurately in patients with CAD. Objective:To evaluate the left ventricular long-axis regional systolic function before and after off-pump coronary artery bypass graft (OPCABG) using real-time tri-plane strain rate imaging.Methods:We recruited30healthy volunteers as control group and30patients with coronary artery disease (CAD) who were treated by OPCABG. In this study, an apical4-chamber view was chosen as the primary image plane. The matrix array transducer then allowed the visualization of4-chamber,2-chamber, and long-axis apical views simultaneously. Echocardiographic data were acquired before OPCABG and a week and3months after OPCABG. The sample was located in the basal, middle and apical segments of interventricular septum and left ventricular wall. The systolic strain rate (SRs) and the postsystolic strain (PSS) were measured.Results:SRs was lower from basal to apical segments in LV wall. Compared with control group, SRs was increased in some segments at a week after OPCABG, and increased in all patients at3months after OPCABG. PSS were emerged in27segments before OPCABG, and decreased after a week and3months (P<0.05). There was a positive correlation with LVEF and MSRs (r=0.68, P<0.01)。Conclusions:Left ventricular long-axis regional systolic function was decreased in patients with coronary artery disease and improved after OPCABG. Real-time tri-plane strain rate imaging can quantitative evaluate left ventricular long-axis regional systolic function before and after OPCABG. Objective:To evaluate left ventricular rotation and twist in patients with coronary artery disease by two-dimensional speckle tracking imaging.Mehods:70patients diagnosed coronary artery disease were included in the stydy and30healthy volunteers as control group. Short-axis parasternal views were taken at the base and the apex of the heart. Using the two-dimensional speckle tracking technique, we analysed the rotation curves at apex and base and calculated the rotation of the subendocardial layers (Ptw-endo), the rotation of the subepicardial layers (Ptw-epi), the globe rotation of the left ventricular (Ptw-bulk) and the transmura torsion (Ptw-mural).Results:There were significant differences in LV rotation and the twist between CAD and control group (P<0.05). Compared with control group, the Ptw-endo, Ptw-epi, Ptw-bulk and Ptw-mural were decreased (P<0.01). According to the Gensini score, we divided the patients into3groups (A, B and C). Compared with control group, the Ptw-endo was decreased (P<0.01), there was no difference in Ptw-epi, the Ptw-bulk and Ptw-mural were decreased (P<0.01) in group A. The Ptw-endo, Ptw-epi, Ptw-bulk and Ptw-mural were decreased (P<0.01) in group B and further decreased in group C, respectively (P<0.01). In the overall population, Ptw-bulk and Ptw-endo were significantly related to LVEF and Gensini score, respectively (P<0.01).Conclusions:The rotation of subendocardial is reduced in patients with coronary artery disease in earlier stage, whereas subendocardial, subepicardial and LV twist was reduced in patients with more servece coronary disease. LV rotational mechanics is affected differently in the subendocardial and subepicardial layers in patients with coronary artery disease. STI can evaluate LV twist accurately in CAD.