Relationship Between Left Ventricular End Diastolic Pressure And Contrast Induced Nephropathy On The Basis Of Low Dose Of Furosemide

Objective: With the increasing use of iodinated contrast medium(CM)in diagnostic and interventional procedures,contrast-induced nephropathy(CIN)is the third most common cause of acute kidney injury.CIN is a sudden compromise of renal function 24-48 h or up to 72 h after administering contrast medium during a CT scan or angiography.This compromise is manifested by an increase in serum creatinine level of more than 25% or 44.2 ummol/L of the baseline,peaking at days 2-5 and remaining high for up to 14 days before returning to the patient's baseline.The precise pathophysiological mechanisms of CIN remain unclear.A large number of studies demonstrate that the complex pathophysiology of CIN involves different mechanisms,such as vasoconstriction,oxidative stress,medullary ischemia,and the direct toxic effects of CM.Because no definitive treatment exists for CIN,the most effective strategy remains prevention.The direct toxic effect of contrast media on renal tubular cells is not only related to the dose of contrast media,but also to the action time.Adequate blood volume is essential for prevention of CIN.Adequate blood volume can not only improve renal ischemia,but also reduce the concentration of contrast media,accelerate the excretion,reduce the toxicity on renal tubule,and thus prevent CIN.Hydration is the guarantee of adequate blood volume.Studies have shown that adequate hydration is the most effective measures for the prevention of CIN.Hydration increased urine flow rate,reduce the contrast agent concentration in the renal tubule,accelerate the excretion of contrast agent,thus reducing renal tubular cells exposed to contrast the time.Previous studies on the effect of hydration and blood volume were less,and the accuracy was low.The left ventricular end diastolic pressure(LVEDP),which represents the preload of the heart,is a gold indicator of the blood volume,which is a invasive examination,but the accuracy is high.By monitoring LVEDP not only to assess blood volume,but also to guide treatment.LVEDP below the normal hint of insufficient blood volume,higher indicate cardiac insufficiency.For patients with PCI,LVEDP in which range can reflect the adequate blood volume,reduce the incidence of CIN were rarely studied.Not only can furosemide increase the renal blood flow but also prevent excessive hydration induced pulmonary edema.Our experiments proved that on the basis of fully hydrated giving small doses of furosemide can prevent contrast-induced nephropathy.This experiment evaluate the blood volume by LVEDP,and the relationship between the LVEDP and CIN at the basic of low dose of furosemide.Methods: From November 2014 to January 2016,439 consecutive patients who underwent PCI in our hospital were considered for enrollment in our study.Patients were categorized into four groups according to LVEDP values measured at the time of cardiac catheterization: LVEDP<15mmHg group(n=117);LVEDP in 15-18mmHg(n=126);LVEDP in 19-22 mmHg group(n=94);LVEDP?23mmHg group(n=102).The basic characteristics and routine examinations were recorded.Four hours before surgery,all patients received a 1ml·kg–1 ·h –1 saline injection.Both groups continued to receive a 1ml·kg–1 ·h–1 saline injection for hydration for 24 h after the surgery.Thus the period of supplemental hydration was from 4 h before to 24 h after surgery.Serum creatinine(Scr)levels was measured before PCI,and 48 h after CM exposure.The creatinine clearance rate(Ccr)was calculated by applying the Cockcroft-Gault formula to the Scr concentration,in which Ccr(ml/min)= [(140-age)×(0.85 femal)×weight]/(72×Scr).And according to the Modification of Diet in Renal Disease(MDRD)to estimate glomerular filtration rate(GFR).GFR(ml/min/1.73 m2)=186×(Scr)-1.154×(age)-0.203(×0.742 femal).So the Ccr and GFR could be calculated.CIN was defined as the application of contrast agents within 48 hours after the serum creatinine increases of 25% or higher earlier 0.5mg/dL.All analyses were performed using SPSS for Windows version 21.0(IBM Corporation).Continuous variables are presented as mean±standard deviation if normal.Comparisons of parametric values between the 2 groups were performed by means of independent-samples Student t tests.The parametric variables were expressed as median(four percentile interval)when they were not normal,and comparison of groups by nonparametric test.Continuous variables were compared with the Wilcoxon rank sum test.Double variable correlation were compared with Spearman correlation analysis.Categorical variables are presented as percentages and compared by the chi-square test.The comparison of serum creatinine concentration,creatinine clearance rate,GFR between four groups were evaluated by repeated measures engineered variance analysis.Receiver-operating characteristic(ROC)analyses were used to detect the cut off value of LVEDP in the prediction of CIN.To determine the independent predictors of CIN,parameters that were found to be significant in the univariate analysis were evaluated by step wise forward logistic regression analysis.Two sided P values<0.05 were considered significant.Results: The baseline characteristics such as age,gender,smoking history,hypertention,acute myocardial infarction(MI),mutivessel disease,statins application,the type of contrast agent,ejection fraction,left ventricle size,BNP,hemoglobin,hs-CRP,24 hours of drinking water and urine volume were not significantly different between the four groups(P>0.05).The body weight,body height,diabetes mellitus,hyperlipidemia,ACEI/ARB application,the dose of contrast agent,E/e',glucose have significant differences between the four groups(P<0.05).There was statistically different between the four groups of glomerular filtration rate and serum creatinine clearance rate(P<0.05).The serum creatinine of LVEDP in 15-18 mmHg group,LVEDP in 19-22 mmHg group,LVEDP?23mmHg group were decreased 48 hours later after coronary angiography,Glomerular filtration rate were higher compared with the previous;While compared with the previous angiography,the serum creatinine of LVEDP<15mmHg group increased and the glomerular filtration rate falled,there was no statistical significance(P>0.05).The creatinine clearance rate were lower compared with the previous in LVEDP<15mmHg group,15-18 mmHg group,and higher in LVEDP?23mmHg group,19-22 mmHg group here was statistical significance(P<0.05).Four groups of contrast nephropathy incidence rates were 10.25%,5.55%,5.31%,0.98%,there was statistical significance(P<0.05).The results of logistic analysis indicated that high LVEDP was benefit for preventing CIN and acute myocardial infarction,ejection fraction,hemoglobin are associated with CIN.The CIN ROC curve was plotted to verify the optimum cut off point for LVEDP,which was 19.5.The AUC for PLR was 64.9%(95% CI:0.550-0.747 P=0.05),with a sensitivity of 43.5% and a specificity of 80%.Spearman correlation analysis showed that LVEDP was negatively related to the size and the incidence of CIN(r=-0.119;P=0.012).LVEDP was positively correlated with E/e'(r=0.103;P=0.032).Conclusion: At basic of low dose furosemide,LVEDP and contrast induced nephropathy had negative correlation,and high LVEDP is a protective factor of CIN.