Effect Of Left Ventricular-arterial Uncoupling On Clinical Prognosis Of Eldly Patients With Septic Shock

Objective:left ventricular-arterial uncoupling always occur to septic shock patients. However the relationship of left ventricular-arterial uncoupling and clinical prognosis remains unknown, this study aimed to investigate the influence of left ventricular-arterial uncoupling on clinical prognosis of eldly patients with septic shock.Methods:We have consecutively enrolled 63 eldly septic shock patients admitted to Department of Intensive Care Unit in Zhejiang Hospital from August 2014 to January 2016. The patients were divided into two groups according to the status of left ventricular-arterial coupling (VAC) at time of septic shock diagnosis as left ventricular-arterial uncoupling group (UC group) and left ventricular-arterial coupling group (C group). Various parameters were recorded for every patient in each group, including general information, acute physiology and chronic health evaluationⅡ (APACHE Ⅱ)score, dose of vasoactive drugs, and the total fluid volume、urine volume per hour within 24 hours of septic shock diagnonsis. We measured blood lactate level, ScvO2, oxygenation index (PaO2/FiO2), some index reflects other organ function including heart、liver、kidney etc, and recorded parameters in Transthoracic echocardiography (TTE) examination. We draw Kaplan-Meier survival curve to evaluate the differences of 28d survival rate between the two groups, and taken pearson correlation analysis to assess the relationship between VAC and index for tissue perfusion or organ function. Univariate and multivariate Cox regression analysis were used to assess the prognostic value of all potential variables for predicting 28-day mortality.Results:(1) 46 patients (73.0%) were in UC group, and 12 patients (27.0%) in C group. Compared with C group, UC group have a lower 28-day survival rate (43.5% vs 76.5%, P=0.021).(2)The blood lactate level at admission (5.54±2.65 mmol/L vs 3.78±1.77 mmol/L, P=0.014) and dose of norepinephrine [lg(NE):-0.416±0.361 vs -0.745±0.346,P=0.002] in UC group were greater than C group. Moreover, ScvO2 [(60.8±3.1)% vs (65.4±2.3)%, P<0.001] and urine volume per hour (0.550±0.418 ml.kg-1.h-1 vs 1.027±0.665 ml.kg-1.h-1, P=0.001) were less than C group. However the difference of the total fluid volume within 24 hours of septic shock diagnonsis (3806.3±831.4 ml vs3142.0±770.0 ml, P=0.016) between two groups was not significant (P>0.05).(3) In terms of organ function, we found that left ventricular ejection fraction [(42.65±5.25)% vs (53.59±4.96)%, P<0.001] and cardiac index(2.378±0.747 L.min-1.m-2 vs 2.934±0.650 L.min-1.m-2, P=0.009) were lower in UC group than C group, and the serum level of NT-proBNP [lg(NT-proBNP):3.886±0.557 vs 3.407±0.535,P=0.003] and cTNI [lg(cTNI):-0.192±0.690 vs -1.046±0.616, P<0.001] were higher than C group. Meanwhile the serum level of ALT、AST and TBIL which can reflects liver function were higher in UC group than C group [lg(ALT):1.942±0.580 vs 1.640±0.359, P=0.001; lg(AST):1.605±0.640 vs 1.166±0.365, P=0.049; lg(TBIL):1.511±0.376 vs 1.298±0.285, P=0.038], the serum level of SCr (169.56±94.35 mmol/L vs 110.84±69.92 mmol/L, P=0.023) and BUN (5.159±3.388 mmol/L vs 2.959±1.839 mmol/L, P=0.002) were also higher in UC group. Although the blood platate level of patients in UC group was less than patients in C group [lg(PLT):1.873±0.304 vs 2.052±0.335,P<0.05], the serum level of DBIL、HbG and PaO2/FiO2 in UC group were similar with C group with no statistically significance (all P>0.05).(4) VAC at time of septic shock diagnosis was significantly, negatively correlated with LVEF、 ScvO2 and lg(PLT) (r=-0.722, P<0.001; r=-0.542, P<0.001; r=-0.308, P=0.014, respectively), and was significantly, postively correlated with lg(NT-proBNP) (r=0.323, P=0.01)、lg(cTNI) (r=0.422, P=0.001)、lg(ALT) (r=0.327, P=0.009)、lg(AST)(r=0.313, P=0.012) and Llg(TBIL)(r=0.277,P=0.028). Multivariate Cox regression analysis showed that VAC (HR=3.518,95%CI:1.648-7.507, P=0.001)、blood lactate level (HR=1.170,95%CI: 1.038-1.319, P=0.01) and hemofiltration therapy (HR=2.247,95%CI:1.017-4.966,P=0.045) were independent risk factors for 28-day mortality of eldly septic shock patients. The optimal cutoff point of VAC for predicting 28-day mortality was 2.14 with a sensibility of 56.7% and specificity of 87.9%, the area under curve (AUC) was 0.74. Further, its predictive value was better than the blood lactate level of which optimal cutoff point was 4.80 mmol/L with a sensibility of 56.7% and specificity of 78.8%, and AUC was 0.705.Conclutions:1. A high frequency of left ventricular-arterial uncoupling happen in eldly patients suffering from septic shock 2. Compared with patients of left ventricular-arterial coupling, patients who with left ventricular-arterial uncoupling have a lower 28-day survival rate, worse cardiac、liver、kidney function and tissue perfusion 3.VAC is a indicator for predicting 28-day mortality of elderly septic shock patients, its predictive value was superior to blood lactate level.