| Background and objectionHyperuricemia(HUA) is a kind of metabolic disorder. In early period, people mainly focused on the HUA effects on joints and kidney, however with the level of serum uric acid(UA) increasing, the risk of cardiovascular disease also increased accordingly. At present, HUA has been proved to be a independent risk factor for cardiovascular disease. A number of studies have showed that the level of serum uric acid has a significant impact on cardiovascular and cerebrovascular diseases, such as coronary atherosclerotic heart disease (CHD), hypertension, diabetes, and cerebral infarction. In recent years, a growing number of studies have shown that there is an interaction between HUA and cardiovascular disease, meanwhile the influence of HUA on cardiovascular has become one of the focus of scholars. HUA is closely related to the morbidity and mortality of cardiovascular disease, and some studies have confirmed that HUA has a major impact on the occurrence, development and prognosis of cardiovascular disease. In recent years, some foreign scholars such as Kivity S, Kavousi have found out that, HUA is an independent risk factor of coronary heart disease. Scholars such as Bickel confirmed that, HUA can significantly predict the severity, prognosis, and fatality rate of cardiovascular disease. Scholars such as Weir have found that, while the blood uric acid each rise by 1.68 mg/dl, the risk of cardiovascular disease will increase for 1.27 fold. After making a comprehensive analysis about domestic and foreign scholars’ research, which is about the effect of HUA on the mechanism of coronary heart disease, we can find out that HUA can affect cardiovascular through inducing inflammation, improving the activity of renin, causing metabolic abnormalities, and participating in the oxidative stress status. At the same time with the rise of uric acid level, the oxidation of LDL cholesterol will promote and the oxidative stress of lipid will accelerate. Therefore, as HUA patients increased year by year, the number of cardiovascular disease also increases accordingly. HUA and its effect on cardiovascular disease have gradually become a public health problems which make a threat to human health, so identify and block the HUA timely can make a contribution to prevent and control cardiovascular disease. Scholars such as Christina Chrysohoou think HUA can cause damage to the left atrial function, and scholars as Christin c. make a prospectie cohort study which showed that the change of left atrial function can be used to predict the hospitalization rates of heart failure in patients with CHD. Therefore, before the cardiac function declines in clinical performance, it is so particularly critical and necessary to detect the impact of HUA on the heart in early time.Left atrial volume tracking (LAVT) provides a method to predict the happening of cardiovascular events. LAVT can evaluate left atrial volume and function accurately and comprehensively, helping clinical doctors take measures to prevent and control further heart attenuation, control the happening of the disease in the clinical stage, and prevent the heart progressing from reversible damage to irreversible damage. Technology about left atrial researching includes:tissue doppler imaging, three-dimensional echocardiography, speckle tracking imaging (STI), biplanar Simpson’s method, length and area method, endovascular intervention method by left atrial pressure volume curve, CT, MRI and so on. LAVT is a new technology developing based on two dimensional tissue tracking, and it can be used to comprehensively evaluate the left atrial volume and function. The technology is designed for left atrium, and the restrictions from left atrium shape and size is relatively small. Compared with three-dimensional echocardiography, there is no Angle dependence of LAVT, which owing high accuracy and fast track calculation and can be operated quickly and easily. STI (also called two-dimensional strain imaging) is mainly used to evaluate the local myocardial function, and it does not have the function to measure the volume if use alone, therefore it has to combine with the double plane Simpson’s method, however LAVT owes the function of volume measurement and function measurement at the same time. So compared with the former, LAVT is more convenient, has more advantages. Compared with intervention, CT and MRI, the technology has the advantages of noninvasive and high repeatability. Comepared with tissue doppler, biplane Simpson’s method, as well as area and length method, the technology can track multiple frames and then gets dynamic change of left atrial volume, after that we can obtain multiple parameters, so it is highly accurate. Therefore, LAVT is more accurate and comprehensive to evaluate the left atrial volume and function compared with other methods, and it leads the diagnosis of left atrial remodeling in patients with HUA to a quantitative and reliable level.At home and abroad, a large number of studies showed that HUA can promote the occurrence and development of cardiovascular disease through effecting left atrial volume and function. Taiwan scholar Kuo-Li Pan etc studied the influence of HUA on left atria using STI, and the results showed that the left ventricular diastolic function of these patients with HUA decrease, left ventricular subclinical contraction is being of dysfunction, and left atrial function decline. But literature reports about HUA’s influence on the left atrial is not much, especially literature about HUA’s effect to the left atrial using the new technology LAVT is still blank. We study the influence of HUA on left atrial applying LAVT, which is advanced and innovative, and the research is of great significance for the treatment, prevention, control and follow-up of cardiovascular disease.The purpose of this study is to explore whether HUA have influence on left atrial volume and function or not through observing the change of parameters from the volume-time curve and volume change rate curve, which is gained from LAVT, then it can provide a prediction method for cardiovascular disease in patients with HUA. LAVT can detect the change of left atrial volume and function in patients with HUA in early time, and then forecast the occurrence and development of coronary heart disease, in addition it can provide useful quantitative auxiliary information for clinical doctors in the evaluation of disease, all of these are so helpful for improving the prognosis of patients. Thus, the research about LAVT applied in HUA’s influence on left atrial is profound and obviously necessity.Methods1.Experimental subjectsCollected 59 hospitalized patients with HUA in the 305 Hospital of People’s Liberation Army on June 6,2014-March 2014, according to the HUA diagnostic criteria and diagnostic criteria in 《Chinese expert consensus about diagnosis and treatment of asymptomatic HUA combined cardiovascular disease》, and gout diagnostic criteria of 1997 American College of Rheumatology, gout patients can be divided into two groups:asymptomatic HUA group 37 cases, which including 28 men and 9 women, age 49 to 56 years old, the average age is (53.3+10.3); Gout group 22 cases, all are male, age 43 to 53 years old, the average age is (48.4+10.8); Excluding the patients suffering from high blood pressure, cardiomyopathy, arrhythmia, congenital heart disease, coronary atherosclerotic heart disease, other serious diseases, having cardiac surgery history, and pacemaker implantation. Collected 36 cases whose uric acid is normal in the 305 Hospital of People’s Liberation Army on September 2014-March 2015, which including 22 man and 14 women, age 49 to 56 years old, average (52.9-9.3). Within the 3 groups, there are 37 cases with diabetes and 38 cases with hyperlipidemia. All Patients have signed informed consent.2.Experimental instrument and methodWe carry out the research using Hitachi Hi Vision Preirus color doppler ultrasonic diagnostic instrument with EUP S70 probes, which frequency is 2～4 MHz, the system equipped with left atrial tracking (LA tracking) software. The body surface area (BSA) is calculated according to patients’height and weight. The patients take the left side, breath quietly, connect electrocardiogram synchronously. Using pulse doppler to measure mitral flow peak velocity of early diastolic blood (peak E), peak flow velocity of late diastolic (A peak), E/A value and E peak deceleration time (DT). Using tissue doppler to measure mitral valve ring peak velocity of early diastolic (Em) and late diastolic peak velocity(Am) of left ventricle outdoor wall from apical four-chamber view,. We capture and storage two-dimensional images of clear apical two chamber and four chamber of three consecutive cardiac cycle.In LA tracking mode, we analysis the dynamic 2D images of apex two chamber and four chamber. In end-diastolic period, when the left atrium endocardial surface shows the most clearly, we sketch left atrial endocardium in manual, and pay attention to avoid the pulmonary vein and left atrial appendage, finally we can acquire curves of left atrial volume-time and left atrial volume change rate. In the left atrial volume-time curve, we can record left atrium maximum volume (LA maximal volume, LAVmax) at the end of the T wave, left atrial systolic volume (LA presystolic volume, LAVpre) at the beginning of P wave, and left atrium minimum volume (LA minimal volume, LAVmin) at the peak of R wave. In the left atrial volume change rate curve, we respectively record left atrial systolic peak filling rate (systolic LA filling rate, dv/dtS, on behalf of the reservoir function), early diastolic peak discharge rate (early diastolic LA emptying rate, dv/dtE, on behalf of the conduit function) and late diastolic peak discharge rate (late diastolic LA emptying rate, dv/dtA, on behalf of the contractile function). After standardizing the volume indicators by BSA, we can get the maximum volume index (LA maximal volume index, LAVImax), presystolic volume index (LA presystolic volume index, LAVIpre) and minimum volume index (LA minimal volume index, LAVImin). We calculate the left atrium total output (LA total emptying volume, LAVt= LAVmax-LAVmin), passive output (LA passive emptying volume, LAVp= LAVmax-LAVpre) and active output (LA active emptying volume, LAVa= LAVpre-LAVmin), after that we can work out the left atrial total ejection fraction (LA total emptying fraction, LAtEF= LAVt/LAVmax), passive ejection fraction (LA passive emptying fraction, LApEF= LAVp/LAVmax) and active ejection fraction (LA active emptying fraction, LAaEF= LAVa/LAVpre).The parameters above are acquired from the average of three cardiac cycle.Results1. There were no statistically significant difference in age, the ratio of diabetes and hyperlipidemia, E/A among the three groups (P> 0.05). Differences were statistically significant in sex, serum uric acid levels, Em values and E/Em values among the three groups (χ2= 11.26, F= 86.32,11.22,6.01, P< 0.05).The serum uric acid level is lower in control group than that in asymptomatic HUA group and gouty group (q= 13.61,17.34, P< 0.05), and the asymptomatic HUA group is lower than that in the gouty group (q= 5.59, P< 0.05). Em values of the asymptomatic HUA group and gouty group were lower than the control group (q = 5.40,5.91, P< 0.05), E/Em values were higher than the control group (q= 4.10, 4.25, P< 0.05), the difference were statistical significant (P< 0.05).2. The differences were statistically significant in LAVImax, LAVIpre and LAVImin among the three groups (F= 9.92,12.45,19.54, P< 0.05); LAVImax of the asymptomatic HUA group and gouty group were higher than the control group (q= 5.30,5.40, P< 0.05), LAVIpre of the asymptomatic HUA group and gouty group were higher than the control group (q= 5.50,6.38, P< 0.05), LAVImin of the control group was lower than asymptomatic HUA group and gouty group (q= 6.34,8.40, P< 0.05), LAVImin of the asymptomatic HUA group was lower than gouty group (q= 2.84, P< 0.05).3. dv/dtS in dv/dtS, dv/dtA, LAtEF, LApEF and LAaEF were statistical significant among the three groups (F=4.16,4.24,19.41,6.74,18.88, all P<0.05); dv/dtS in asymptomatic hyperuricemia group and gouty group were higher than that in control group (q=2.84,3.88, all P<0.05), dv/dtA in gouty group was higher than that in control group and asymptomatic hyperuricemia group (q=4.12,2.64, all P < 0.05), LAtEF in control group was higher than that in asymptomatic hyperuricemia group and gouty group (q=5.56,8.90, all P<0.05), LAtEF in asymptomatic hyperuricemia group was higher than that in gouty group (q=4.14, P< 0.05), LAaEF in control group was higher than that in asymptomatic hyperuricemia group and gouty group (q=5.08,8.82, all P<0.05), LAaEF in asymptomatic hyperuricemia group was higher than that in gouty group (q=4.41, P<0.05).Conclusions1. LAVT can track left atrial remodeling of hyperuricemia patients in real time. With the increasing of uric acid level and the deterioration of the clinical symptoms, left atrial remodeling is becoming more and more obvious, left atrial volume is increasing, the reservoir function and contractile function of left atrium are enhancing.2. While the serum uric acid increasing, by the adjustment of the left atrium itself, the volume indicators and functional indicators increase compensatorily, which make the left ventricle filling achieve dynamic balance.3. As the blood uric acid levels increase, the left ventricular diastolic function decline.4. LAVImin, LAtEF and LAaEF are the most sensitive parameters reflecting differences among the three groups. |
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