Evaluation Of Rotation And Torsion In Endocardial And Epicardial Layers Based On The Concept Of Space-time With Chronic Kidney Disease (CKD)Patients

Objective To assess the rotation and torsion of chronic kidney disease (CKD) in endocardial and epicardial layers with two-dimensional speckle tracking technology (STI). We can evaluate cardiac function in patients with different stages of CKD from two aspects of time and space, and understand its initial change in different planes and phases at the same time.Methods According to the renal staging criteria of The National Kidney Foundation Disease Outcomes Quality Initiative (K/DOQI),1-3period were assigned to the CKD1group,4-5period were assigned to the CKD2group. Each group included25cases.25normal patients were on control group. Conventional measuring result of3groups were obtained by ultrasonography, which including left ventricular ejection fraction(LVEF), heart rate(HR), Isovolumic relaxation time(IVRT), LA, and LVIDd. The blood flow velocity of mitral annulus during early diastole(E) and atrial contraction(A) were also measured by pulsed Doppler echocardiography and E/A ratio was calculated. The velocity of movement of mitral annulus during early diastole(e) and atrial contraction(a) and systole(Sm) were also measured by tissue Doppler imaging(TDI) and e/a ratio was calculated too. The rotation angle and orientation of endocardium and epicardium in left ventricular basal and apical lever were obtained at each phase using STI, and meanwhile the torsion in endocardium and epicardium were calculated. Using the formula:UntwR=(rotation of AVC-rotation of MVO)/rotation of AVC*100%/IVRT, we can calculate the Untwisting rate(UntwR). Conventional measuring result and rotation and torsion of endocardium and epicardium in different phases were compared, and the UntwR were contrasted at the same time. Studying the relationship between rotation and torsion of endocardium and epicardium and LVEF by correlation analysis, the relationship between UntwR and E/A ratio,IVRT.Results Conventional measuring result:Compared with control group, The e, E/A, and e/a of both CKD1and CKD2group were lower than control group significantly (P<0.05). Besides, the E, Sm and LVEF of CKD2was reduced, the LVIDd was increases. The IVRT, LA, a, A, and E/e of both CKD1and CKD2group were larger than control group significantly (P<0.05). STI:①During isovolumic contraction period, endocardium and epicardium in basal level of3groups were counterclockwise, endocardium and epicardium in apical level of 3groups were clockwise. The rotation of endocardium and epicardium in both basal and apical levels in patients with CKD had no significant change.②uring ejection period, endocardium and epicardium in basal level of3groups were clockwise, endocardium and epicardium in apical level of3groups were counterclockwise. The endocardial rotation in both basal and apical planes of CKD1and CKD2were markedly decreased compared with control group (P<0.05). The epicardial rotation in both basal and apical planes of CKD2were decreased, while CKD1was not statistically reduced (P>0.05). There was significant difference in epicardial rotation in apical plane betweem CKDl and CKD2with statistical meanings (P<0.05).③At the end of isovolumic diastole, the endocardium and epicardium in both basal and apical levels were untwisting inversely. The UntwR of endocardium in both basal and apical planes of CKD1and CKD2reduced significantly. The UntwR of epicardium in basal plane of both CKD1and CKD2decreased significantly, compared with control group (P<0.05).④Compared with normal controls, the endocardial torsion were markedly decreased in both CKD1and CKD2(P<0.05), and meanwhile the epicardial torsion was reduced in CKD2(P<0.05). The UntwR of endocardium were reduced obviously in patients with CKD, while the UntwR of epicardium had no difference among3groups, correlation analysis:the endocardial and epicardial torsion was positively correlated with LVEF (order:r=0.645, r=0.395, P<0.001), moreover, the correlation of endocardial torsion was stronger than epicardial torsion. The endocardial and epicardial rotation in basal level were negatively related with LVEF. The endocardial rotation in apical level was positively correlated with LVEF moderately. The UntwR of endocardium was positively correlated with E/A ratio. The UntwR of endocardium and epicardium were negatively related with IVRT.Conclusion STI can find the abnormal rotation and torsion of CKD patients before the LVEF decline. What’s more, STI has a potential ability to evaluate when and where the heart function have changed first in patients with CKD by measuring the rotation of endocardium and epicardium of left ventricle.