Longitudinal Left Ventricular Function In Uremic Patients Quantitatively Assessed By Velocity Vector Imaging Prior And After Hemodialysis

Background:Background:Cardiac impairment is common in patients with uremia and account for about 50%of uremic mortality.Mortality of uremic patients in uremic patients are 5～10 times higher than those without kidney disfunction.Although dialysis has been widely used and can elevate survival rate of chronic renal failure,cardiac complications are common causes (about 40%)of death in ueremic patients underwent long-term dialysis. Morbidities of heart failure,coronary heart disease and cardiovascular event remain high in course of hemodialysis(HD).A few researches about changes of left ventricular(LV)longitudinal systolic function and studies about effect of single HD on LV systolic and diastolic function in uremic patients who underwent HD are reported,but the results are controversial.VVI is a new method to non-invasively detect regional myocardial function.VVI is angle-independent and not affected by cardiac twist movement and dragging motion of neighbor segment in comparison with Doppler tissue imaging.It can quantitatively assess regional myocardial systolic and diastolic function accurately.Objective:To evaluate LV longitudinal systolic and diastolic function of uremic patients using VVI before and after a single HD session.Investigate acute effect of single HD on LV systolic and diastolic function in patients who underwent HD.Subjectd and Methods:30 patients who underwent HD in our hospital from May,2007～December,2007 were enrolled.All patients were free from clinically overt cardiac dysfunction.Exclusive criteria include presence of sinus arrhythmia,pericardial effusion,severe mitral regurgitation,acute/intermittent acute disease,diabetes mellitus,tumor,coronary artery disease and myocardial infarction.Two-dimensional echocardiography was performed and digital dynamic imaging was collected 30 min prior and after a single HD session. Longitudinal velocity,strain and strain rate in systolic and diastolic(early and later)period were analyzed using VVI software,respectively.Each parameter was measured 3 times and average value was obtained.Differences of each parameter prior and after HD session and between uremic and control group were analyzed between the two groups using statistic method..Results:In comparison with control group,longitudinal myocardial velocity,strain and strain rate in each segment in early systolic and diastolic period were significantly lower prior and after HD in uremic group(P＜0.05); myocardial velocity and strain rate in late diastolic period were significantly lower(P＜0.05),whereas myocardial strain had no significant changes(P＞0.05). Compared with prior HD session,longitudinal myocardial velocity,strain and strain rate of all segments in systolic period reduced(P＜0.01),of which ten segments(basic,medial and apical segments of anterior wall,basic and medial segment of anterior septum wall and lateral wall,basic segment of posterior wall and inferior wall,medial segment of posterior septum wall)had statistically significance(P＜0.05);myocardial velocity,strain and strain rate in early diastolic period were significantly lower(P＜0.01).Velocity,strain and strain rate in later diastolic had no significant changes(P＞0.05).Conclusion:VVI can objectively and sensitively detect LV longitudinal systolic and diastolic function prior and after HD session in uremic patients. Longitudinal myocardial diastolic and systolic function in each segment was lower in uremic patients.especially the diastolic function.LV longitudinal diastolic function in all segments reduced after a single HD session,and systolic function reduced in some segments.A single HD may do negative effect on LV function,so we should observe and monitor cardiac function,if necessary,to prevent cardiovascular event when uremic patients undergoing HD session.