Experimental Study Of Ultrasonic Integrated Backscatter In Assessment Of Myocardial Damage Of Chronic Renal Failure

Objective: To investigate the changes of myocardial integrated backscatter(IBS) parameters during the development of chronic renal failure (CRF) in rabbits, and explore the value of ultrasonic integrated backscatter in assessment of myocardial damage of chronic renal failure.Methods: Fifteen rabbits were daily injected cationic bovine serum albumin (C-BSA) intravenously for 8 weeks to establish CRF models. Before C-BSA injection and 2, 4, 6, 8weeks after C-BSA injection conventional echocardiographic parameters were obtained; the normalized IBS (IBS%) and cyclic variation of integrated backscatter amplitude (CVIB) of septum and posterior wall of the left ventricular were measured in the parasternal long-axis view using Acoustic Densitometry analytical software. At the same time point Serum creatinine (Scr) and blood urea nitrogen (BUN) were determined. Then a rabbit was killed randomly at each time point, its kidney and heart were sampled for pathological examination. Compare the changes of myocardial integrated backscatter parameters during the development of chronic renal failure (CRF) in rabbits using the pathology and blood tests as reference.Results:①IBS changed periodically before C-BSA injection, the value was maximal at end diastole and minimal at end systole, and myocardial integrated backscatter time intensity curve is like sine wave curve, at 4 w,6 w,8 w post C-BSA injection, IBS% of the septum and posterior wall of the left ventricular was gradually increased (P<0.05 or P<0.01), septum:increased from (70.88±3.99)% to (81.23±2.58)% , posterior wall: increased from (71.27±1.91)% to (79.69±2.15)%; CVIB was progressively decreased (P<0.05 or P<0.01), septum:decreased from (8.50±0.72)dB to (5.67±0.43)dB; posterior wall: decreased from (10.18±2.24)dB to (5.22±0.80)dB.②Conventional echographic parameters, including left ventricular wall thickness, dimensions, ejection fraction, fractional shortening and E/A ratio showed no significant differences(P﹥0.05).③The level of Scr and BUN has significantly increased since 6w after injection of C-BSA(P<0.05 or P<0.01).④From 4w to 6w post C-BSA injection the myocardial pathological examination showed that myocardial cells arranged irregularly, myocardial cells hypertrophy, interstitial fibrous tissue increased, at 8w post C-BSA injection interstitial fibrosis was appeared and vacuo bubble was founded in cytoplasm. And the kindney pathological examination exhibited glomerular cyst cavity expanding, glomerular cell swelling and exudates; at 8w post C-BSA injection pathological studies showed glomerular sclerosis and renal interstitial fibrosis. Conclusions:Myocardial ultrasonic integrated backscatter can detect the myocardial histopathological changes of chronic renal failure sensitively and quantitatively during CRF.