预测脓毒症患者心脏功能障碍和死亡率的多生物标记物策略

Multi-biomarker strategy for prediction of myocardial dysfunction and mortality in sepsis 预测脓毒症患者心脏功能障碍和死亡率的多生物标记物策略 1 first-author 1 corresp ‡Corresponding Authors ‡Corresponding Authors †E-mail:2314029@zju.edu.cn2313003@zju.edu.cn †E-mail:2314029@zju.edu.cn2313003@zju.edu.cn 2314029@zju.edu.cn 2 corresp ‡Corresponding Authors ‡Corresponding Authors †E-mail:2314029@zju.edu.cn2313003@zju.edu.cn †E-mail:2314029@zju.edu.cn2313003@zju.edu.cn 2314029@zju.edu.cn Department of Cardiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China Department of Cardiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China Intensive Care Unit, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China Intensive Care Unit, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China Objective: 2 The present study was to evaluate the feasibility of using the multi-biomarker strategy for the prediction of sepsis-induced myocardial dysfunction (SIMD) and mortality in septic patients. Methods: 2 Brain natriuretic peptide (BNP), cardiac troponin I (cTnI), and heart-type fatty acid-binding protein (h-FABP) in 147 septic patients were assayed within 6 h after admission. We also determined the plasma levels of myeloperoxidase (MPO) and pregnancy-associated plasma protein-A (PAPP-A). The receiver operating characteristic (ROC) curve was used to assess the best cutoff values of various single-biomarkers for the diagnosis of SIMD and the prediction of mortality. Also, the ROC curve, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) indices were used to evaluate the feasibility of using multi-biomarkers to predict SIMD and mortality. Results: 2 Our statistics revealed that only h-FABP independently predicted SIMD ( P < 0.05). The addition of MPO and cTnI to h-FABP for SIMD prediction provided an NRI of 18.7% ( P =0.025) and IDI of 3.3% ( P =0.033). However, the addition of MPO or cTnI to h-FABP did not significantly improve the predictive ability of h-FABP to SIMD, as evidenced by the area under the curve (AUC), NRI, and IDI (all P > 0.05). A history of shock and MPO were independent predictors of mortality in septic patients (both P < 0.05). The addition of PAPP-A and h-FABP to MPO resulted in a mortality prediction with NRI of 25.5% ( P =0.013) and IDI of 2.9% ( P =0.045). However, this study revealed that the addition of h-FABP or PAPP-A to MPO did not significantly improve the ability to predict mortality, as evidenced by the AUC, NRI, and IDI (all P > 0.05). Conclusions: 2 The findings of this study indicate that a sensitive and specific strategy for early diagnosis of SIMD and mortality prediction in sepsis should incorporate three biomarkers. 目的 2 评估联合应用多种生物标记物以预测脓毒症患者早期心脏功能障碍及28天死亡率的可行性. 创新点 2 (1)通过净重分类改善(NRI)和综合辨别改善(IDI)指标,评估多种生物标志物策略相比单一生物标志物策略对脓毒症患者心脏功能障碍及28天死亡率的预测价值.(2)评估心脏型脂肪酸结合蛋白(h-FABP)、髓过氧化物酶(MPO)以及妊娠相关血浆蛋白A(PAPP-A)等新型生物标记物在脓毒症中的临床预测价值. 方法 2 检测147例脓毒症患者在入院后6小时内血浆中脑钠肽(BNP)、心肌肌钙蛋白I(cTnI)、h-FABP、MPO及PAPP-A的水平.使用受试者工作特征(ROC)曲线来评估各种单一生物标志物在脓毒症患者心脏功能障碍诊断和28天死亡率预测中的最佳截止值.采用ROC曲线、NRI和IDI指标评估多种生物标志物策略相比单一生物标志物策略在预测脓毒症相关心脏功能障碍及28天死亡率中的价值. 结论 2 MPO、cTnI和h-FABP联合应用显著提高了对脓毒症患者心脏功能障碍的预测能力,同时PAPP-A、MPO和h-FABP联合应用显著提高了预测脓毒症患者28天死亡率的能力. Multi-biomarker Myocardial dysfunction Sepsis Mortality 多种生物标志物 心脏功能障碍 脓毒症 死亡率 Introduction 1 Sepsis refers to a life-threatening organ dysfunction caused by a dysregulated host response to bacterial, fungal, or viral infection (Singer et al., 2016 2016 ; Huber et al., 2018 2018 ). Sepsis affects approximately 19 million patients in the world each year, of which 6 million succumb to the disease. The mortality rate due to sepsis is more than 1/4 of all intensive care unit (ICU) deaths, and about 3 million of the surviving patients develop cognitive dysfunction (Perner et al., 2018 2018 ). Sepsis-induced myocardial dysfunction (SIMD) occurs in 25% to 50% of all adult septic shock patients (Jardin et al., 1999 1999 ). First described by Parker et al. ( 1984 1984 ), SIMD refers to a reversible myocardial injury. SIMD encompasses peripheral vascular dysfunction and myocardial dysfunction, and is characterized by left ventricular dilatation, lower ejection fraction, and myocardial damage (Sato and Nasu, 2015 2015 ). Traditional biomarkers of myocardial dysfunction including brain natriuretic peptide (BNP) and cardiac troponin (cTn) appear to be associated with SIMD and prognosis in septic patients (Post et al., 2008 2008 ; Kim et al., 2019 2019 ). Other studies demonstrate that BNP and cTn alone were positively correlated with the severity of sepsis (Charpentier et al., 2004 2004 ; Klouche et al., 2014 2014 ; Papanikolaou et al., 2014 2014 ), regardless of whether cardiac function was damaged. However, this relation could be disappeared after attenuation of the severity of sepsis (Berdal et al., 2008 2008 ; Yucel et al., 2008 2008 ). In recent years, novel biomarkers, such as heart-type fatty acid-binding protein (h-FABP) and pregnancy-associated plasma protein-A (PAPP-A), were identified to predict the myocardial dysfunction and poor outcome in patients with sepsis (Zhang et al., 2012 2012 , 2014 2014 ), but the predictive values of PAPP-A and h-FABP alone were limited. Additionally, myeloperoxidase (MPO) was also considered as a potential biomarker for cardiovascular disease and sepsis (Schrijver et al., 2017 2017 ; Avaliani et al., 2019 2019 ). We hypothesized that the use of multi-biomarker is more valuable than use of single-biomarker in the early diagnosis of cardiac dysfunction and the prognosis of septic patients. Therefore, a prospective observational study was conducted to compare the efficiency of multi-biomarker with single-biomarker in predicting SIMD and mortality in patients with sepsis. Patients and methods 1 Participants 2 The present study involved 147 septic patients admitted to the ICUs (emergency ICU, neurological ICU, and medical ICU) at the Second Affiliated Hospital of Zhejiang University School of Medicine (Hangzhou, China), from April 2012 to December 2016. The diagnostic criteria of severe sepsis and septic shock were defined according to the 2001 International Sepsis Definitions Conference (Levy et al., 2003 2003 ). Patients who met the diagnostic criteria were treated with 6-h resuscitation and 24-h management bundles detailed in the Surviving Sepsis Campaign guidelines (Dellinger et al., 2008 2008 ). The exclusion criteria were pregnancy, life expectancy less than 24 h, preexisting left ventricular dysfunction, dilated cardiomyopathy, valvular heart disease, chronic renal failure, acute coronary ischemia, and cardiogenic or hemorrhagic shock. Both clinical and biologic data were collected during the follow-up period. The data included demographic characteristics such as age, gender, and comorbidities including chronic obstructive pulmonary disease (COPD), stroke, and trauma. Details of both peripheral blood biochemistry panel and arterial blood gas analysis were taken at admission. Three clinical scores were recorded: the initial severity was assessed by the Acute Physiology and Chronic Health Evaluation II (APACHE-II) score (range 0 to 71), the Sequential Organ Failure Assessment (SOFA) score (range 0 to 24), and the Multiple Organ Dysfunction Syndrome (MODS) score (range 0 to 24) within 24 h after admission. Both the need for and the timing of inotropic support defined as a continuous infusion of inotropes (milrinone or dobutamine) or vasopressors (dopamine, epinephrine, norepinephrine, or vasopressin) based on the professional guidelines were also recorded (Dellinger et al., 2008 2008 ). Mortality was defined as patients who died within 28 d after enrollment (ACCP/SCCM, 1992 1992 ). All clinical events and outcomes were followed throughout the hospitalization period. Patient follow-up was limited to the period of hospitalization. Blood sampling 2 Central venous blood was sampled within 6 h after admission. For detection of complete blood count, conventional biochemical assay, and levels of cTnI, h-FABP, MPO, PAPP-A, and procalcitonin (PCT), serum samples were collected after 15-min centrifugation at 3000 g (4 °C) and stored at −40 °C until the assay was done. For BNP measurement, plasma samples were isolated from 4 mL ethylenediamine tetraacetic acid (EDTA) whole blood after 10-min centrifugation at 3000 g (4 °C) and stored at −40 °C until the assay was done. Besides, 0.5 mL of heparinized arterial blood was collected for an instant blood gas analysis. Lactate detection was done using an automated analyzer (ABL800; Radiometer Co., Denmark) with the matched reagent. Biochemical assays 2 Complete blood count was assessed from serum samples using an automated system (XN9000; Sysmex Co., Japan). Liver function, renal function, and electrolytes were assessed for serum samples using a chemistry analyzer (AU 5800; Beckman Coulter Inc., USA) with a commercially available reagent. Serum PCT and cTnI levels were determined using immunoluminometric assay (Cobas E601, Roche, Switzerland). All samples were analyzed in triplicate. Plasma samples for detection of BNP levels were run in an immunoassay analyzer (Triage, Biosite Inc., USA) using the appropriate kit. Serum PAPP-A, h-FABP, and MPO levels were detected by a sandwich enzyme-linked immunosorbent assay (ELISA) using commercially available kits (Kangchen Bioscience, Shanghai, China). Transthoracic echocardiographic detection 2 Early recognition of SIMD was ensured by conducting transthoracic echocardiography (Sonos-550, Philips, USA) on all participants within 24 h after enrollment. An experienced cardiologist evaluated the left ventricular ejection fraction (LVEF). SIMD was defined as an LVEF less than 50% or the need of inotropes (milrinone or dobutamine) or vasopressors (dopamine, epinephrine, norepinephrine, or vasopressin) or both. Statistical analysis 2 Continuous variables and categorical variables were described through mean±standard deviation (SD) and percentage (%), respectively. PCT, h-FABP, cTnI, BNP, PAPP-A, and MPO levels were presented as the median (25th/75th percentile) because they were skewed. Furthermore, h-FABP, cTnI, BNP, PAPP-A, and MPO levels were logarithmically normalized using the natural logarithm to the base e (presented as ln h-FABP, ln cTnI, ln BNP, ln PAPP-A, and ln MPO), where e is an irrational constant approximately equal to 2.72 to account for the skewed distribution. Baseline characteristics between groups (patients with SIMD and without SIMD; survivals and non-survivals) were compared using either the Chi-square for binary variables or categorical variables, Student’s t -test for non-skewed continuous variables, or the Mann-Whitney test for skewed continuous variables. Odds ratios (ORs) for SIMD and mortality were assessed using logistic regression analysis at a 95% confidence interval (CI). Predictive indicators that were significant in univariate analysis were included in a multivariate model using a forward selection procedure. The receiver operating characteristic (ROC) curve and calculation of the area under the curve (AUC) were conducted to compare the predictive abilities of different variables. The best cutoff values were determined using the Youden index. ROC curve was also constructed using a combination of two or three variables for predicting SIMD and mortality applying the Mackinnon and Mulligan ( 1998 1998 )’s weighted sum rule. The differences between AUCs were tested by Hanley-McNeil methods to examine whether the addition of one or two of the biomarkers improved the bias of the model (Hanley and McNeil, 1983 1983 ). An improvement in risk prediction for biomarkers is assessed by the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices (Pencina et al., 2008 2008 ). NRI was calculated from the net increase versus decrease in risk categories among case patients, minus that among control patients. The NRI determined whether a priori meaningful risk existed among the categories. We used < 10%, 10% to < 30%, and 30% to 50%, and > 50% for the risk stratifications of SIMD and septic death (Cook and Ridker, 2009 2009 ). IDI is the difference in Yates slopes between models, where the Yates slope is the average difference in predicted probabilities between case participants and control patients (Cook and Ridker, 2009 2009 ). Statistical analyses were done using MedCalc 15 software and SPSS (Version 23.0 for Windows; IBM Corp., Armonk, NY, USA). A P value of < 0.05 was considered statistically significant. Results 1 Baseline characteristics according to SIMD 2 A total of 147 patients were divided into the SIMD group ( n =70) and the non-SIMD group ( n =77) depending on whether the left heart function was impaired. The baseline characteristics and laboratory indicators of patients are represented in Table 1 1 . The mean age of patients was 66.0 years, and men accounted for 81.6% of the patients. According to the APACHE-II, SOFA, and MODS scores, there were no significant differences in the severity of organ dysfunction between the two groups. The APACHE-II scores for the non-SIMD and SIMD groups were 18.9±3.2 and 19.4±2.8 ( P =0.193), respectively, the SOFA scores were 10.4±2.5 and 10.3±2.0 ( P =0.871), and the MODS scores were 11.4±2.5 and 11.4±2.2 ( P =0.825), respectively. The cTnI, h-FABP, and MPO levels were significantly higher in patients with SIMD as compared to patients without SIMD ( P =0.038, P < 0.0005, and P =0.011, respectively). There were no significant differences in PAPP-A or BNP between the two groups ( P =0.359 and P =0.267, respectively). Besides, there was no significant difference in whether the patients had a history of shock, stroke, or trauma ( P =0.914, P =0.251, or P =0.136, respectively). However, the number of patients with COPD in the SIMD group was significantly higher than that in the non-SIMD group ( P =0.007). Data are expressed as mean±standard deviation (SD), number (percentage), or median (25th/75th percentile). SIMD: sepsis-induced myocardial dysfunction; ICU: intensive care unit; COPD: chronic obstructive pulmonary disease; cTnI: cardiac troponin I; BNP: brain natriuretic peptide; h-FABP: heart-type fatty acid-binding protein; PAPP-A: pregnancy-associated plasma protein-A; MPO: myeloperoxidase; PCT: procalcitonin; APACHE-II: Acute Physiology and Chronic Health Evaluation II; SOFA: Sequential Organ Failure Assessment; MODS: Multiple Organ Dysfunction Syndrome Characteristics All patients ( n =147) Patients with SIMD ( n =70) Patients without SIMD ( n =77) P Age (year) 66.0±15.5 65.2±14.1 66.8±16.6 0.592 Sex, male 120 (81.6%) 57 (81.4%) 63 (81.8%) 0.879 Treatment day in ICU 22.3±9.1 22.8±9.0 21.8±9.1 0.285 Stroke 82 (55.8%) 43 (61.4%) 39 (51.0%) 0.251 Trauma 86 (58.5%) 36 (51.4%) 50 (64.9%) 0.136 Shock 50 (34.0%) 23 (32.9%) 27 (35.1%) 0.914 COPD 72 (49.0%) 43 (61.4%) 29 (37.7%) 0.007 cTnI (μg/L) 0.91 (0.13/1.37) 0.97 (0.22/1.86) 0.83 (0.08/1.24) 0.038 BNP (pg/mL) 637.0 (398.5/1010.0) 678.0 (405.8/1080.0) 610.0 (347.0/887.5) 0.267 h-FABP (ng/mL) 9.59 (5.94/12.06) 11.35 (9.01/14.13) 8.06 (5.47/10.16) <0.0005 PAPP-A (ng/mL) 4.49 (2.38/6.61) 4.57 (2.51/6.71) 4.44 (2.11/6.44) 0.359 MPO (ng/mL) 13.96 (10.13/22.99) 17.62 (11.29/23.38) 12.11 (8.62/17.23) 0.011 PCT (μg/L) 3.90 (1.99/5.35) 3.18 (2.00/5.35) 3.50 (1.87/5.35) 0.756 APACHE-II score (points) 19.2±3.0 19.4±2.8 18.9±3.2 0.193 SOFA score (points) 10.3±2.3 10.3±2.0 10.4±2.5 0.871 MODS score (points) 11.4±2.3 11.4±2.2 11.4±2.5 0.825 Predictive ability to SIMD 2 Univariate logistic regression analysis demonstrated that higher plasma concentrations of cTnI, h-FABP, and MPO ( P =0.027, P =0.000, and P =0.001, respectively) indicated a higher risk of developing SIMD (Table 2 2 ). The BNP and PAPP-A concentrations, MODS, SOFA and APACHE-II scores, and history of shock, stroke, and trauma did not accurately predict SIMD. However, a history of COPD accurately predicted SIMD (OR=2.636, P =0.004). A multivariate analysis using a model with COPD disease history, cTnI, h-FABP, and MPO found that only h-FABP independently predicted SIMD ( P =0.000). SIMD: sepsis-induced myocardial dysfunction; OR: odds ratio; CI: confidence interval; COPD: chronic obstructive pulmonary disease; BNP: brain natriuretic peptide; h-FABP: heart-type fatty acid-binding protein; PAPP-A: pregnancy-associated plasma protein-A; cTnI: cardiac troponin I; MPO: myeloperoxidase; PCT: procalcitonin; APACHE-II: Acute Physiology and Chronic Health Evaluation II; SOFA: Sequential Organ Failure Assessment; MODS: Multiple Organ Dysfunction Syndrome Predictor OR 95% CI P Univariate analysis  Age 0.993 0.937 to 1.014 0.537  COPD 2.636 1.354 to 5.133 0.004  Shock 0.906 0.457 to 1.796 0.778  Stroke 1.522 0.805 to 2.992 0.190  Trauma 0.572 0.295 to 1.109 0.098  ln BNP 1.215 0.821 to 1.792 0.330  ln h-FABP 8.900 3.406 to 23.257 0.000  ln PAPP-A 1.258 0.796 to 1.990 0.326  ln cTnI 1.299 1.030 to 1.638 0.027  ln MPO 2.922 1.550 to 5.510 0.001  ln PCT 1.013 0.725 to 1.416 0.939  APACHE-II score 1.054 0.946 to 1.173 0.339  SOFA score 0.968 0.840 to 1.115 0.651  MODS score 0.999 0.870 to 1.148 0.992 Multivariate analysis  ln h-FABP 8.900 3.406 to 23.256 0.000 An ROC curve (Fig. 1a 1a ) was established to evaluate the predictive value of the above single index for SIMD. The AUC of h-FABP was 0.754 ( P < 0.01), MPO was 0.645 ( P < 0.01), cTnI was 0.618 ( P =0.010), BNP was 0.545 ( P =0.348), and PAPP-A was 0.524 ( P =0.614). The sensitivity and specificity of h-FABP at the optimal cutoff value of 10.16 ng/mL were 68.6% and 77.9%, respectively. The optimal cutoff value of MPO was 14.27 ng/mL, which gave a sensitivity of 70.1% and a specificity of 60.0%. The cTnI was 1.27 μg/L, and it provided a sensitivity of 81.8% and a specificity of 35.7%. ROC: receiver operating characteristic; BNP: brain natriuretic peptide; cTnI: cardiac troponin I; h-FABP: heart-type fatty acid-binding protein; MPO: myeloperoxidase; PAPP-A: pregnancy-associated plasma protein-A; SIMD: sepsis-induced myocardial dysfunction; AUC: area under the curve Combination of biomarkers to predict SIMD 2 An ROC curve was developed to evaluate whether MPO and cTnI, both singly and in combination with h-FABP, improve the prediction level of SIMD (Fig. 2a 2a ). MPO alone (AUC=0.762) or cTnI alone (AUC=0.748) or both (AUC=0.765), in combination with h-FABP, did not significantly increase the AUC of h-FABP by Hanley-McNeil periods ( P =0.494, P =0.548, and P =0.482, respectively). The combination of cTnI and MPO (AUC=0.679) was inferior to h-FABP in predicting SIMD. NRI and IDI were more sensitive tests for improving model discrimination than ROC curves (Pencina et al., 2008 2008 ). In Table 3 3 , the addition of MPO and cTnI to h-FABP provided an NRI of 18.7% ( P =0.025) and IDI of 3.3% ( P =0.033). The NRI and IDI of MPO combined with h-FABP were 9.2% ( P =0.212) and 1.8% ( P =0.108), respectively, and the NRI and IDI of cTnI added to h-FABP were 9.5% ( P =0.103) and 0.8% ( P =0.353), respectively. ROC: receiver operating characteristic; SIMD: sepsis-induced myocardial dysfunction; h-FABP: heart-type fatty acid-binding protein; cTnI: cardiac troponin I; MPO: myeloperoxidase; PAPP-A: pregnancy-associated plasma protein-A; AUC: area under the curve NRI: net reclassification improvement; IDI: integrated discrimination improvement; SIMD: sepsis-induced myocardial dysfunction; h-FABP: heart-type fatty acid-binding protein; MPO: myeloperoxidase; cTnI: cardiac troponin I  Logarithm of the variable NRI (%) P value for NRI IDI (%) P value for IDI  ln h-FABP+ln MPO+ln cTnI 18.7 0.025 3.3 0.033  ln h-FABP+ln MPO 9.2 0.212 1.8 0.108  ln h-FABP+ln cTnI 9.5 0.103 0.8 0.353 Characteristics of patients according to mortality 2 The comparisons of patients’ characteristics based on the mortality data are shown in Table 4 4 . Comparison of the non-survival and survival groups revealed that there were no differences in age, sex, MODS score, SOFA score, APACHE-II score, or a history of COPD, stroke and trauma. However, patients with a history of shock had a significantly higher probability of death within 28 d than survival ( P =0.000). Plasma levels of h-FABP, PAPP-A, BNP, and MPO in the dead group were significantly higher than those in the survival group ( P =0.03, P =0.002, P =0.018, and P < 0.0005, respectively). However, PCT and cTnI levels were similar in the two groups ( P =0.838 and P =0.063, respectively). Data from the APACHE-II, SOFA, and MODS scores indicated that the degree of sepsis was not significantly different between the two groups (Table 4 4 ). Data are expressed as mean±standard deviation (SD), number (percentage), or median (25th/75th percentile). ICU: intensive care unit; COPD: chronic obstructive pulmonary disease; cTnI: cardiac troponin I; BNP: brain natriuretic peptide; h-FABP: heart-type fatty acid-binding protein; PAPP-A: pregnancy-associated plasma protein-A; MPO: myeloperoxidase; PCT: procalcitonin; APACHE-II: Acute Physiology and Chronic Health Evaluation II; SOFA: Sequential Organ Failure Assessment; MODS: Multiple Organ Dysfunction Syndrome  Characteristics 28-d survivals ( n =79) 28-d non-survivals ( n =68) P  Age (year) 63.9±15.8 68.5±14.7 0.086  Sex, male 66 (83.5%) 54 (79.4%) 0.666  Treatment day in ICU 18.4±8.2 25.7±8.5 0.000  Stroke 41 (51.9%) 34 (50.0%) 0.392  Trauma 47 (59.5%) 39 (57.4%) 0.925  Shock 16 (20.3%) 34 (50.0%) 0.000  COPD 40 (50.6%) 32 (47.1%) 0.790  cTnI (μg/L) 0.93 (0.14/1.25) 0.91 (0.12/1.76) 0.063  BNP (pg/mL) 626.0 (346.5/870.0) 707.5 (409.5/1305.5) 0.018  h-FABP (ng/mL) 8.44 (4.96/10.99) 10.16 (8.40/12.20) 0.030  PAPP-A (ng/mL) 3.57 (1.99/6.36) 4.72 (2.92/7.42) 0.002  MPO (ng/mL) 12.62 (8.37/17.80) 15.65 (10.59/26.15) <0.0005  PCT (μg/L) 3.50 (1.89/5.65) 3.30 (1.99/5.30) 0.838  APACHE-II score (points) 19.1±3.0 19.2±3.0 0.791  SOFA score (points) 10.4±2.4 10.2±2.2 0.470  MODS score (points) 11.1±2.3 11.8±2.3 0.109 Predictive values of biomarkers for mortality 2 As shown in Table 5 5 , univariate logistic regression analysis showed that PAPP-A, h-FABP, MPO, and a history of shock indicated a higher risker of mortality ( P =0.021, P =0.003, P =0.000, and P =0.000, respectively). Multivariate analysis demonstrated that MPO and a history of shock were associated with mortality ( P =0.001 and P =0.002, respectively). According to the Fig. 1b 1b , the calculated AUC for MPO was 0.674 ( P < 0.01), h-FABP was 0.631 ( P < 0.01), PAPP-A was 0.607 ( P =0.022), BNP was 0.571 ( P =0.146), and cTnI was 0.544 ( P =0.365). The best cutoff value of MPO was 10.05 ng/mL, which provided a sensitivity of 92.7% and a specificity of 34.1%. The best cutoff value for h-FABP was 8.01 ng/mL (77.9% sensitivity and 49.4% specificity), and PAPP-A was 3.23 ng/mL (72.1% sensitivity and 46.8% specificity). OR: odds ratio; CI: confidence interval; COPD: chronic obstructive pulmonary disease; BNP: brain natriuretic peptide; h-FABP: heart-type fatty acid-binding protein; PAPP-A: pregnancy-associated plasma protein-A; cTnI: cardiac troponin I; MPO: myeloperoxidase; PCT: procalcitonin; APACHE-II: Acute Physiology and Chronic Health Evaluation II; SOFA: Sequential Organ Failure Assessment; MODS: Multiple Organ Dysfunction Syndrome Predictor OR 95% CI P Univariate analysis  Age 1.019 0.998 to 1.042 0.077  COPD 0.807 0.453 to 1.659 0.666  Shock 3.937 1.905 to 8.138 0.000  Stroke 1.407 0.730 to 2.713 0.307  Trauma 0.916 0.474 to 1.768 0.793  ln BNP 1.408 0.944 to 2.099 0.093  ln h-FABP 3.271 1.482 to 7.221 0.003  ln PAPP-A 1.767 1.091 to 2.863 0.021  ln cTnI 1.068 0.854 to 1.336 0.563  ln MPO 3.683 1.874 to 7.236 0.000  ln PCT 1.083 0.774 to 1.516 0.641  APACHE II score 1.027 0.923 to 1.143 0.627  SOFA score 0.966 0.839 to 1.113 0.635  MODS score 1.140 0.988 to 1.315 0.072 Multivariate analysis  Shock 3.193 1.506 to 6.769 0.002  ln MPO 3.238 1.594 to 6.577 0.001 Combination of biomarkers to predict mortality 2 The addition of either PAPP-A alone (AUC=0.686) or h-FABP alone (AUC=0.695) or both (AUC=0.711) to MPO did not significantly improve the predictive ability of MPO by Hanley-McNeil periods ( P =0.611, P =0.369, and P =0.224, respectively; Fig. 2b 2b ). Besides, the combination of h-FABP and PAPP-A (AUC=0.661) was lower than MPO alone for predicting prognosis of septic patients. According to Table 6 6 , the addition of PAPP-A and h-FABP to MPO yielded an NRI of 25.5% ( P =0.013) and IDI of 2.9% ( P =0.045) as compared with MPO. NRI and IDI for MPO combined with h-FABP to predict mortality were 13.7% ( P =0.051) and 1.7% ( P =0.131), respectively, and MPO combined with PAPP-A were 8.9% ( P =0.211) and 1.1% ( P =0.200), respectively. NRI: net reclassification improvement; IDI: integrated discrimination improvement; MPO: myeloperoxidase; PAPP-A: pregnancy-associated plasma protein-A; h-FABP: heart-type fatty acid-binding protein Logarithm of the variable NRI (%) P value for NRI IDI (%) P value for IDI  ln MPO+ln PAPP-A+ln h-FABP 25.5 0.013 2.9 0.045  ln MPO+ln PAPP-A 8.9 0.211 1.1 0.200  ln MPO+ln h-FABP 13.7 0.051 1.7 0.131 Discussion 1 SIMD is the primary determinant of the outcome of septic shock and increases the mortality of septic patients (Blanco et al., 2008 2008 ). Therefore, early diagnosis and aggressive supportive therapy for SIMD are recommended (Annane et al., 2005 2005 ). It is imperative to develop biomarkers that effectively help to monitor and treat sepsis (Riedemann et al., 2003 2003 ). The multi-biomarker strategy may provide a better predictive value for SIMD and prognosis of sepsis. Our study used biomarkers with predictive value to evaluate the ability of multi-biomarkers to predict SIMD and outcome in septic patients. h-FABP is a small cytoplasmic protein found within cardiomyocytes that have recently emerged as a cardiac biomarker (Alhadi and Fox, 2010 2010 ). The h-FABP is rapidly released from cardiomyocytes into blood circulation shortly after the occurrence of an ischemic episode (Glatz et al., 1988 1988 ; Alhadi and Fox, 2010 2010 ). Some studies (Nakata et al., 2003 2003 ; O'Donoghue et al., 2006 2006 ) have reported that h-FABP is a promising biomarker for acute coronary syndrome (ACS) and cardiac dysfunction (Arimoto et al., 2005 2005 ; Kadowaki et al., 2017 2017 ). It has also been reported that h-FABP is a biomarker for mortality in patients with sepsis and septic shock (Jo et al., 2012 2012 ) and is associated with SIMD (Zhang et al., 2012 2012 ). In our study, h-FABP had good diagnostic value for SIMD and was significantly higher in non-survivors than in survivors. The capability of h-FABP to diagnose SIMD was higher than that of cTnI and MPO (AUC: 0.754 vs. 0.618 vs. 0.645, OR: 8.900 vs. 1.299 vs. 2.922). However, the accuracy of h-FABP for the early diagnosis of SIMD, as quantified by the AUC, was not significantly high. Although h-FABP provided predictive value to evaluate the outcome of sepsis, its AUC was relatively low (AUC < 0.70). The exact mechanism leading to the elevated h-FABP levels in septic patients is uncertain. It is hypothesized that h-FABP is released from cardiomyocytes following cardiac dysfunction (Glatz et al., 1988 1988 ). It is also speculated that the catabolism of glycogen and lipids during severe sepsis and septic shock increases the free fatty acid level, which subsequently elevates h-FABP concentrations (Yan et al., 2009 2009 ). MPO is a heme-containing peroxidase mostly secreted by activated neutrophils and has strongly oxidative activity (Kothari et al., 2011 2011 ). MPO catalyzes nitric oxide (NO) consumption and therefore reduces the bioavailability of NO and impairs its vasodilation and anti-inflammatory functions (Podrez et al., 2000 2000 ; Fu et al., 2001 2001 ). MPO is considered both a marker and mediator of vascular inflammation, and is associated with increased cardiovascular events (Baldus et al., 2003 2003 ) and increased risk of mortality in patients with ACS (Kolodziej et al., 2019 2019 ). Besides, recent studies (Ng et al., 2006 2006 ; Avaliani et al., 2019 2019 ) indicated that MPO had diagnostic and prognostic values in chronic heart failure (HF). As a novel biomarker, MPO could also aid in the prognosis of septic patients (Schrijver et al., 2017 2017 ) and hence, is a potential biomarker for SIMD and mortality in sepsis. The present study revealed that MPO is also an independent predictor of mortality in septic patients. The predictive mortality ability of MPO was superior to that of PAPP-A and h-FABP, as manifested from the AUC (0.674 vs. 0.607 vs. 0.631). The association between MPO and mortality could be due to that MPO directly damages extracellular collateral and is an inflammatory marker, which causes organ failure (Schrijver et al., 2017 2017 ). Besides, elevated MPO concentrations could detect SIMD in septic patients, as evidenced by the calculation of AUC. The mechanism might be that leukocyte-mediated oxidation reactions play a critical role in heart remodeling processes. The activation of polymorphonuclear cells is associated with increased plasma concentrations of MPO (Askari et al., 2003 2003 ; Melenovsky et al., 2014 2014 ). However, our study reveals that the accuracy of MPO in predicting SIMD and septic mortality is relatively low, as demonstrated by the AUC (all AUC < 0.70). BNP is a neurohormone secreted by cardiac ventricles in response to pressure overload. This neurohormone promotes natriuresis and diuresis, diastolic blood vessel, and antagonizes the vasoconstriction effects of the renin-angiotensin-aldosterone system. Besides, the secretion of BNP depends on the filling pressure of the left ventricle and extension of the myocardial wall. The increase in serum concentrations of BNP is valuable in the diagnosis of SIMD and prognosis of septic patients (Witthaut et al., 2003 2003 ; Post et al., 2008 2008 ). However, previous research (Charpentier et al., 2004 2004 ) and recent observational study (Papanikolaou et al., 2014 2014 ) demonstrated that the severity of illness, rather than SIMD, is the primary cause of increased BNP in septic patients. The use of BNP alone to predict SIMD may be, therefore, not recommended. In our research, patient’s BNP levels at the point of admission did not accurately predict SIMD or adverse outcomes in septic patients. As pathological markers of acute myocardial infarction, the assay of cTn is the gold standard for the diagnosis of acute myocardial injury (Park et al., 2017 2017 ). Serum levels of cTnI are also increased in blood flow-restricted coronary artery diseases, including pulmonary embolism, sepsis, myocarditis, and acute stroke (Fromm, 2007 2007 ). Several studies (Mehta et al., 2004 2004 ; Bessière et al., 2013 2013 ; Kim et al., 2019 2019 ) have shown that cTnI is associated with myocardial injury in patients with sepsis and can predict the outcome of patients. In the current study, increased serum cTnI levels at admission were found to be a predictor of SIMD, but it was not associated with mortality. PAPP-A is in the metzincin superfamily of metalloproteinases. The PAPP-A glycoprotein is produced by the placental syncytiotrophoblast during pregnancy and fibroblasts, osteoblasts, and vascular smooth muscle cells (Consuegra-Sanchez et al., 2009 2009 ). High serum concentrations of PAPP-A are associated with HF (Funayama et al., 2011 2011 ). Besides, a study indicated that elevated levels of plasma PAPP-A could predict myocardial dysfunction and death in patients with severe sepsis (Zhang et al., 2014 2014 ). According to our results, high levels of PAPP-A predict the risk of death in patients with sepsis, but its predictive value is relatively low (AUC=0.607). Therefore, PAPP-A was not feasible in the early diagnosis of SIMD. Systemic inflammation, sepsis-related vascular damages, and the administration of heparin and insulin to patients may be related to the elevated serum PAPP-A concentrations (Pellitero et al., 2007 2007 ; Wittfooth et al., 2011 2011 ). Although h-FABP and MPO were good indicators for SIMD and mortality, the calculation of AUC indicated that their predictive value was unsatisfactory. To improve the prediction accuracy of SIMD and mortality in septic patients, this study, therefore, combined two or three biomarkers. The result revealed that the addition of cTnI or MPO or both to h-FABP did not significantly improve the predictive ability for SIMD. The contribution of new biomarkers based on the ROC curve is immense, but this method has been highly criticized because it is insensitive in comparing models (Pepe et al., 2004 2004 ) and has little direct clinical relevance (Janes et al., 2008 2008 ). Several new techniques have, therefore, been proposed to evaluate and compare predictive risk models (Cook and Ridker, 2009 2009 ). The present study used a more sensitive test to improve model discrimination (Pencina et al., 2008 2008 ). We found that the addition of cTnI and MPO to h-FABP significantly improved the early diagnosis capacity of SIMD by the IDI (18.7% P =0.025) and NRI (3.3%, P =0.033) indices. However, the SIMD diagnosis capacities of IDI and NRI indices did not significantly increase through the addition of cTnI alone or MPO alone to h-FABP. The reason for choosing h-FABP, MPO, and cTnI combined to predict SIMD was that h-FABP, MPO, and cTnI were predictive indicators for SIMD through the AUC in our study. Furthermore, h-FABP and cTnI have been proved as sensitive biomarkers for myocardial injury (Arimoto et al., 2005 2005 ; Kadowaki et al., 2017 2017 ; Park et al., 2017 2017 ). The addition of h-FABP or PAPP-A to MPO slightly improved its mortality predictive ability, as demonstrated by AUC, NRI, and IDI. Although the AUC showed that the addition of PAPP-A and h-FABP to MPO did not significantly improve the predictive ability, NRI (13.7%, P =0.051) and IDI (1.7%, P =0.131) were statistically significant. Inflammation is the pathophysiological basis of sepsis and MPO and PAPP-A are the indicators of inflammation, which may explain that the combination of MPO, PAPP-A, and h-FABP significantly improve the ability to predict outcome of sepsis. Our current study had several limitations. First, it was a retrospective cohort study of prospectively collected data from one center. Second, the number of patients in our study was insufficient and may influence the outcome. Third, NRI depends on the specific categories of risk stratification used (Cook and Ridker, 2009 2009 ). Our study used < 10%, 10% to < 30%, 30% to 50%, and > 50% risk stratifications for SIMD and mortality. The NRI is affected by risk stratification, while risk stratification is currently not well recognized. Conclusions 1 Our study revealed that MPO and h-FABP were good predictors of myocardial dysfunction and outcome in septic patients. PAPP-A can serve as a useful biomarker for prognosis in septic patients. Also, this study revealed that cTnI provided predictive value for SIMD. Through the calculated IDI and NRI indices, the addition of MPO and cTnI to h-FABP could significantly improve the ability to predict mortality and the combination of MPO, PAPP-A, and h-FABP significantly improved the predictive ability to SIMD in septic patients. References SCCM ACCP/ . American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference: definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis . Crit Care Med , 1992 . 20 ( 6 ): 864 - 874 . 1597042 . American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference: definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis HA Alhadi , KAA Fox . Heart-type fatty acid-binding protein in the early diagnosis of acute myocardial infarction: the potential for influencing patient management . Sultan Qaboos Univ Med J , 2010 . 10 ( 1 ): 41 - 49 . 21509080 . Heart-type fatty acid-binding protein in the early diagnosis of acute myocardial infarction: the potential for influencing patient management D Annane , E Bellissant , JM Cavaillon . Septic shock . Lancet , 2005 . 365 ( 9453 ): 63 - 78 . 15639681 DOI: 10.1016/s0140-6736(04)17667-8 http://doi.org/10.1016/s0140-6736(04)17667-8 . Septic shock T Arimoto , Y Takeishi , R Shiga , 等 . Prognostic value of elevated circulating heart-type fatty acid binding protein in patients with congestive heart failure . J Card Fail , 2005 . 11 ( 1 ): 56 - 60 . 15704065 DOI: 10.1016/j.cardfail.2004.03.005 http://doi.org/10.1016/j.cardfail.2004.03.005 . Prognostic value of elevated circulating heart-type fatty acid binding protein in patients with congestive heart failure AT Askari , ML Brennan , XR Zhou , 等 . Myeloperoxidase and plasminogen activator inhibitor 1 play a central role in ventricular remodeling after myocardial infarction . J Exp Med , 2003 . 197 ( 5 ): 615 - 624 . 12615902 DOI: 10.1084/jem.20021426 http://doi.org/10.1084/jem.20021426 . Myeloperoxidase and plasminogen activator inhibitor 1 play a central role in ventricular remodeling after myocardial infarction T Avaliani , T Talakvadze , S Tabagari . Prognostic value of plasma myeloperoxidase level’s and echocardiographic determinants in chronic heart failure patients . Georgian Med News , 2019 . ( 288 ): 55 - 60 . 31101776 . Prognostic value of plasma myeloperoxidase level’s and echocardiographic determinants in chronic heart failure patients S Baldus , C Heeschen , T Meinertz , 等 . Myeloperoxidase serum levels predict risk in patients with acute coronary syndromes . Circulation , 2003 . 108 ( 12 ): 1440 - 1445 . 12952835 DOI: 10.1161/01.cir.0000090690.67322.51 http://doi.org/10.1161/01.cir.0000090690.67322.51 . Myeloperoxidase serum levels predict risk in patients with acute coronary syndromes JE Berdal , K Stavem , T Omland , 等 . Prognostic merit of N-terminal-proBNP and N-terminal-proANP in mechanically ventilated critically ill patients . Acta Anaesthesiol Scand , 2008 . 52 ( 9 ): 1265 - 1272 . 18823467 DOI: 10.1111/j.1399-6576.2008.01737.x http://doi.org/10.1111/j.1399-6576.2008.01737.x . Prognostic merit of N-terminal-proBNP and N-terminal-proANP in mechanically ventilated critically ill patients F Bessière , S Khenifer , J Dubourg , 等 . Prognostic value of troponins in sepsis: a meta-analysis . Intensive Care Med , 2013 . 39 ( 7 ): 1181 - 1189 . 23595497 DOI: 10.1007/s00134-013-2902-3 http://doi.org/10.1007/s00134-013-2902-3 . Prognostic value of troponins in sepsis: a meta-analysis J Blanco , A Muriel-Bombín , V Sagredo , 等 . Incidence, organ dysfunction and mortality in severe sepsis: a Spanish multicentre study . Crit Care , 2008 . 12 ( 6 ): R158 19091069 DOI: 10.1186/cc7157 http://doi.org/10.1186/cc7157 . Incidence, organ dysfunction and mortality in severe sepsis: a Spanish multicentre study J Charpentier , CE Luyt , Y Fulla , 等 . Brain natriuretic peptide: a marker of myocardial dysfunction and prognosis during severe sepsis . Crit Care Med , 2004 . 32 ( 3 ): 660 - 665 . 15090944 DOI: 10.1097/01.ccm.0000114827.93410.d8 http://doi.org/10.1097/01.ccm.0000114827.93410.d8 . Brain natriuretic peptide: a marker of myocardial dysfunction and prognosis during severe sepsis L Consuegra-Sanchez , S Fredericks , JC Kaski . Pregnancy-associated plasma protein-A (PAPP-A) and cardiovascular risk . Atherosclerosis , 2009 . 203 ( 2 ): 346 - 352 . 18789800 DOI: 10.1016/j.atherosclerosis.2008.07.042 http://doi.org/10.1016/j.atherosclerosis.2008.07.042 . Pregnancy-associated plasma protein-A (PAPP-A) and cardiovascular risk NR Cook , PM Ridker . Advances in measuring the effect of individual predictors of cardiovascular risk: the role of reclassification measures . Ann Intern Med , 2009 . 150 ( 11 ): 795 - 802 . 19487714 DOI: 10.7326/0003-4819-150-11-200906020-00007 http://doi.org/10.7326/0003-4819-150-11-200906020-00007 . Advances in measuring the effect of individual predictors of cardiovascular risk: the role of reclassification measures RP Dellinger , MM Levy , JM Carlet , 等 . Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2008 . Intensive Care Med , 2008 . 34 ( 1 ): 17 - 60 . 18058085 DOI: 10.1007/s00134-007-0934-2 http://doi.org/10.1007/s00134-007-0934-2 . Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2008 Jr RE Fromm . Cardiac troponins in the intensive care unit: common causes of increased levels and interpretation . Crit Care Med , 2007 . 35 ( 2 ): 584 - 588 . 17205004 DOI: 10.1097/01.ccm.0000254349.10953.be http://doi.org/10.1097/01.ccm.0000254349.10953.be . Cardiac troponins in the intensive care unit: common causes of increased levels and interpretation XY Fu , SY Kassim , WC Parks , 等 . Hypochlorous acid oxygenates the cysteine switch domain of pro-matrilysin (MMP-7). A mechanism for matrix metalloproteinase activation and atherosclerotic plaque rupture by myeloperoxidase . J Biol Chem , 2001 . 276 ( 44 ): 41279 - 41287 . 11533038 DOI: 10.1074/jbc.M106958200 http://doi.org/10.1074/jbc.M106958200 . Hypochlorous acid oxygenates the cysteine switch domain of pro-matrilysin (MMP-7). A mechanism for matrix metalloproteinase activation and atherosclerotic plaque rupture by myeloperoxidase A Funayama , T Shishido , S Netsu , 等 . Serum pregnancy-associated plasma protein a in patients with heart failure . J Card Fail , 2011 . 17 ( 10 ): 819 - 826 . 21962420 DOI: 10.1016/j.cardfail.2011.05.011 http://doi.org/10.1016/j.cardfail.2011.05.011 . Serum pregnancy-associated plasma protein a in patients with heart failure JFC Glatz , M van Bilsen , RJA Paulussen , 等 . Release of fatty acid-binding protein from isolated rat heart subjected to ischemia and reperfusion or to the calcium paradox . Biochim Biophys Acta , 1988 . 961 ( 1 ): 148 - 152 . 3260112 DOI: 10.1016/0005-2760(88)90141-5 http://doi.org/10.1016/0005-2760(88)90141-5 . Release of fatty acid-binding protein from isolated rat heart subjected to ischemia and reperfusion or to the calcium paradox JA Hanley , BJ McNeil . A method of comparing the areas under receiver operating characteristic curves derived from the same cases . Radiology , 1983 . 148 ( 3 ): 839 - 843 . 6878708 DOI: 10.1148/radiology.148.3.6878708 http://doi.org/10.1148/radiology.148.3.6878708 . A method of comparing the areas under receiver operating characteristic curves derived from the same cases W Huber , U Mayr , A Umgelter , 等 . Mandatory criteria for the application of variability-based parameters of fluid responsiveness: a prospective study in different groups of ICU patients . J Zhejiang Univ-Sci B (Biomed & Biotechnol) , 2018 . 19 ( 7 ): 515 - 524 . DOI: 10.1631/jzus.B1700243 http://doi.org/10.1631/jzus.B1700243 . Mandatory criteria for the application of variability-based parameters of fluid responsiveness: a prospective study in different groups of ICU patients H Janes , MS Pepe , W Gu . Assessing the value of risk predictions by using risk stratification tables . Ann Intern Med , 2008 . 149 ( 10 ): 751 - 760 . 19017593 DOI: 10.7326/0003-4819-149-10-200811180-00009 http://doi.org/10.7326/0003-4819-149-10-200811180-00009 . Assessing the value of risk predictions by using risk stratification tables F Jardin , T Fourme , B Page , 等 . Persistent preload defect in severe sepsis despite fluid loading: a longitudinal echocardiographic study in patients with septic shock . Chest , 1999 . 116 ( 5 ): 1354 - 1359 . 10559099 DOI: 10.1378/chest.116.5.1354 http://doi.org/10.1378/chest.116.5.1354 . Persistent preload defect in severe sepsis despite fluid loading: a longitudinal echocardiographic study in patients with septic shock YH Jo , K Kim , JH Lee , 等 . Heart-type fatty acid-binding protein as a prognostic factor in patients with severe sepsis and septic shock . Am J Emerg Med , 2012 . 30 ( 9 ): 1749 - 1755 . 22463971 DOI: 10.1016/j.ajem.2012.02.005 http://doi.org/10.1016/j.ajem.2012.02.005 . Heart-type fatty acid-binding protein as a prognostic factor in patients with severe sepsis and septic shock S Kadowaki , T Watanabe , Y Otaki , 等 . Combined assessment of myocardial damage and electrical disturbance in chronic heart failure . World J Cardiol , 2017 . 9 ( 5 ): 457 - 465 . 28603594 DOI: 10.4330/wjc.v9.i5.457 http://doi.org/10.4330/wjc.v9.i5.457 . Combined assessment of myocardial damage and electrical disturbance in chronic heart failure JS Kim , M Kim , YJ Kim , 等 . Troponin testing for assessing sepsis-induced myocardial dysfunction in patients with septic shock . J Clin Med , 2019 . 8 ( 2 ): 239 DOI: 10.3390/jcm8020239 http://doi.org/10.3390/jcm8020239 . Troponin testing for assessing sepsis-induced myocardial dysfunction in patients with septic shock K Klouche , S Pommet , L Amigues , 等 . Plasma brain natriuretic peptide and troponin levels in severe sepsis and septic shock: relationships with systolic myocardial dysfunction and intensive care unit mortality . J Intensive Care Med , 2014 . 29 ( 4 ): 229 - 237 . 23753226 DOI: 10.1177/0885066612471621 http://doi.org/10.1177/0885066612471621 . Plasma brain natriuretic peptide and troponin levels in severe sepsis and septic shock: relationships with systolic myocardial dysfunction and intensive care unit mortality AR Kolodziej , M Abo-Aly , E Elsawalhy , 等 . Prognostic role of elevated myeloperoxidase in patients with acute coronary syndrome: a systemic review and meta-analysis . Mediat Inflamm, 2019:2872607 , 2019 . DOI: 10.1155/2019/2872607 http://doi.org/10.1155/2019/2872607 . Prognostic role of elevated myeloperoxidase in patients with acute coronary syndrome: a systemic review and meta-analysis N Kothari , RS Keshari , J Bogra , 等 . Increased myeloperoxidase enzyme activity in plasma is an indicator of inflammation and onset of sepsis . J Crit Care , 2011 . 26 ( 4 ): 435.e1 - 435e7 . DOI: 10.1016/j.jcrc.2010.09.001 http://doi.org/10.1016/j.jcrc.2010.09.001 . Increased myeloperoxidase enzyme activity in plasma is an indicator of inflammation and onset of sepsis MM Levy , MP Fink , JC Marshall , 等 . 2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference . Intensive Care Med , 2003 . 29 530 - 538 . 12664219 DOI: 10.1007/s00134-003-1662-x http://doi.org/10.1007/s00134-003-1662-x . 2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference A Mackinnon , R Mulligan . Combining cognitive testing and informant report to increase accuracy in screening for dementia . Am J Psychiatry , 1998 . 155 ( 11 ): 1529 - 1535 . 9812113 DOI: 10.1176/ajp.155.11.1529 http://doi.org/10.1176/ajp.155.11.1529 . Combining cognitive testing and informant report to increase accuracy in screening for dementia NJ Mehta , IA Khan , V Gupta , 等 . Cardiac troponin I predicts myocardial dysfunction and adverse outcome in septic shock . Int J Cardiol , 2004 . 95 ( 1 ): 13 - 17 . 15159032 DOI: 10.1016/j.ijcard.2003.02.005 http://doi.org/10.1016/j.ijcard.2003.02.005 . Cardiac troponin I predicts myocardial dysfunction and adverse outcome in septic shock V Melenovsky , SJ Hwang , G Lin , 等 . Right heart dysfunction in heart failure with preserved ejection fraction . Eur Heart J , 2014 . 35 ( 48 ): 3452 - 3462 . 24875795 DOI: 10.1093/eurheartj/ehu193 http://doi.org/10.1093/eurheartj/ehu193 . Right heart dysfunction in heart failure with preserved ejection fraction T Nakata , A Hashimoto , M Hase , 等 . Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome . Cardiology , 2003 . 99 ( 2 ): 96 - 104 . 12711885 DOI: 10.1159/000069726 http://doi.org/10.1159/000069726 . Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome LL Ng , B Pathik , IW Loke , 等 . Myeloperoxidase and C-reactive protein augment the specificity of B-type natriuretic peptide in community screening for systolic heart failure . Am Heart J , 2006 . 152 ( 1 ): 94 - 101 . 16824837 DOI: 10.1016/j.ahj.2005.09.020 http://doi.org/10.1016/j.ahj.2005.09.020 . Myeloperoxidase and C-reactive protein augment the specificity of B-type natriuretic peptide in community screening for systolic heart failure M O'Donoghue , JA de Lemos , DA Morrow , 等 . Prognostic utility of heart-type fatty acid binding protein in patients with acute coronary syndromes . Circulation , 2006 . 114 ( 6 ): 550 - 557 . 16880323 DOI: 10.1161/circulationaha.106.641936 http://doi.org/10.1161/circulationaha.106.641936 . Prognostic utility of heart-type fatty acid binding protein in patients with acute coronary syndromes J Papanikolaou , D Makris , M Mpaka , 等 . New insights into the mechanisms involved in B-type natriuretic peptide elevation and its prognostic value in septic patients . Crit Care , 2014 . 18 ( 3 ): R94 24887309 DOI: 10.1186/cc13864 http://doi.org/10.1186/cc13864 . New insights into the mechanisms involved in B-type natriuretic peptide elevation and its prognostic value in septic patients KC Park , DC Gaze , PO Collinson , 等 . Cardiac troponins: from myocardial infarction to chronic disease . Cardiovasc Res , 2017 . 113 ( 14 ): 1708 - 1718 . 29016754 DOI: 10.1093/cvr/cvx183 http://doi.org/10.1093/cvr/cvx183 . Cardiac troponins: from myocardial infarction to chronic disease MM Parker , JH Shelhamer , SL Bacharach , 等 . Profound but reversible myocardial depression in patients with septic shock . Ann Intern Med , 1984 . 100 ( 4 ): 483 - 490 . 6703540 DOI: 10.7326/0003-4819-100-4-483 http://doi.org/10.7326/0003-4819-100-4-483 . Profound but reversible myocardial depression in patients with septic shock S Pellitero , JL Reverter , E Pizarro , 等 . Pregnancy-associated plasma protein-A levels are related to glycemic control but not to lipid profile or hemostatic parameters in type 2 diabetes . Diabetes Care , 2007 . 30 ( 12 ): 3083 - 3085 . 17728480 DOI: 10.2337/dc07-1092 http://doi.org/10.2337/dc07-1092 . Pregnancy-associated plasma protein-A levels are related to glycemic control but not to lipid profile or hemostatic parameters in type 2 diabetes MJ Pencina , RB D'Agostino , Jr RB D'Agostino , 等 . Evaluating the added predictive ability of a new marker: from area under the ROC curve to reclassification and beyond . Stat Med , 2008 . 27 ( 2 ): 157 - 172 . 17569110 DOI: 10.1002/sim.2929 http://doi.org/10.1002/sim.2929 . Evaluating the added predictive ability of a new marker: from area under the ROC curve to reclassification and beyond MS Pepe , H Janes , G Longton , 等 . Limitations of the odds ratio in gauging the performance of a diagnostic, prognostic, or screening marker . Am J Epidemiol , 2004 . 159 ( 9 ): 882 - 890 . 15105181 DOI: 10.1093/aje/kwh101 http://doi.org/10.1093/aje/kwh101 . Limitations of the odds ratio in gauging the performance of a diagnostic, prognostic, or screening marker A Perner , M Cecconi , M Cronhjort , 等 . Expert statement for the management of hypovolemia in sepsis . Intensive Care Med , 2018 . 44 ( 6 ): 791 - 798 . 29696295 DOI: 10.1007/s00134-018-5177-x http://doi.org/10.1007/s00134-018-5177-x . Expert statement for the management of hypovolemia in sepsis EA Podrez , M Febbraio , N Sheibani , 等 . Macrophage scavenger receptor CD36 is the major receptor for LDL modified by monocyte-generated reactive nitrogen species . J Clin Invest , 2000 . 105 ( 8 ): 1095 - 1108 . 10772654 DOI: 10.1172/jci8574 http://doi.org/10.1172/jci8574 . Macrophage scavenger receptor CD36 is the major receptor for LDL modified by monocyte-generated reactive nitrogen species F Post , LS Weilemann , CM Messow , 等 . B-type natriuretic peptide as a marker for sepsis-induced myocardial depression in intensive care patients . Crit Care Med , 2008 . 36 ( 11 ): 3030 - 3037 . 18824903 DOI: 10.1097/CCM.0b013e31818b9153 http://doi.org/10.1097/CCM.0b013e31818b9153 . B-type natriuretic peptide as a marker for sepsis-induced myocardial depression in intensive care patients NC Riedemann , RF Guo , PA Ward . Novel strategies for the treatment of sepsis . Nat Med , 2003 . 9 ( 5 ): 517 - 524 . 12724763 DOI: 10.1038/nm0503-517 http://doi.org/10.1038/nm0503-517 . Novel strategies for the treatment of sepsis R Sato , M Nasu . A review of sepsis-induced cardiomyopathy . J Intensive Care, 3:48 , 2015 . DOI: 10.1186/s40560-015-0112-5 http://doi.org/10.1186/s40560-015-0112-5 . A review of sepsis-induced cardiomyopathy IT Schrijver , H Kemperman , M Roest , 等 . Myeloperoxidase can differentiate between sepsis and non-infectious SIRS and predicts mortality in intensive care patients with SIRS . Intensive Care Med Exp, 5:43 , 2017 . DOI: 10.1186/s40635-017-0157-y http://doi.org/10.1186/s40635-017-0157-y . Myeloperoxidase can differentiate between sepsis and non-infectious SIRS and predicts mortality in intensive care patients with SIRS M Singer , CS Deutschman , CW Seymour , 等 . The third international consensus definitions for sepsis and septic shock (sepsis-3) . JAMA , 2016 . 315 ( 8 ): 801 - 810 . 26903338 DOI: 10.1001/jama.2016.0287 http://doi.org/10.1001/jama.2016.0287 . The third international consensus definitions for sepsis and septic shock (sepsis-3) S Wittfooth , R Tertti , M Lepäntalo , 等 . Studies on the effects of heparin products on pregnancy-associated plasma protein A . Clin Chim Acta , 2011 . 412 ( 3-4 ): 376 - 381 . 21094153 DOI: 10.1016/j.cca.2010.11.024 http://doi.org/10.1016/j.cca.2010.11.024 . Studies on the effects of heparin products on pregnancy-associated plasma protein A R Witthaut , C Busch , P Fraunberger , 等 . Plasma atrial natriuretic peptide and brain natriuretic peptide are increased in septic shock: impact of interleukin-6 and sepsis-associated left ventricular dysfunction . Intensive Care Med , 2003 . 29 ( 10 ): 1696 - 1702 . 12915939 DOI: 10.1007/s00134-003-1910-0 http://doi.org/10.1007/s00134-003-1910-0 . Plasma atrial natriuretic peptide and brain natriuretic peptide are increased in septic shock: impact of interleukin-6 and sepsis-associated left ventricular dysfunction GT Yan , J Lin , XH Hao , 等 . Heart-type fatty acid-binding protein is a useful marker for organ dysfunction and leptin alleviates sepsis-induced organ injuries by restraining its tissue levels . Eur J Pharmacol , 2009 . 616 ( 1-3 ): 244 - 250 . 19576209 DOI: 10.1016/j.ejphar.2009.06.039 http://doi.org/10.1016/j.ejphar.2009.06.039 . Heart-type fatty acid-binding protein is a useful marker for organ dysfunction and leptin alleviates sepsis-induced organ injuries by restraining its tissue levels T Yucel , D Memiş , B Karamanlioglu , 等 . The prognostic value of atrial and brain natriuretic peptides, troponin I and C-reactive protein in patients with sepsis . Exp Clin Cardiol , 2008 . 13 ( 4 ): 183 - 188 . 19343164 . The prognostic value of atrial and brain natriuretic peptides, troponin I and C-reactive protein in patients with sepsis ZC Zhang , HW Dai , YH Yu , 等 . Usefulness of heart-type fatty acid-binding protein in patients with severe sepsis . J Crit Care , 2012 . 27 ( 4 ): 415.e13 - 415e18 . DOI: 10.1016/j.jcrc.2012.01.004 http://doi.org/10.1016/j.jcrc.2012.01.004 . Usefulness of heart-type fatty acid-binding protein in patients with severe sepsis ZC Zhang , HW Dai , YH Yu , 等 . Elevated pregnancy-associated plasma protein A predicts myocardial dysfunction and death in severe sepsis . Ann Clin Biochem , 2014 . 51 ( 1 ): 22 - 29 . 23880622 DOI: 10.1177/0004563213489275 http://doi.org/10.1177/0004563213489275 . Elevated pregnancy-associated plasma protein A predicts myocardial dysfunction and death in severe sepsis Compliance with ethics guidelines Fa-chao CHEN, Yin-chuan XU, and Zhao-cai ZHANG declare that they have no conflict of interest. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5). Written informed consent was required from all participants or their legal proxies before registration for being included in the study. 10.1631/jzus.B2000049 Project supported by the Zhejiang Provincial Natural Science Foundation of China (No. LQ16H020003) and the National Natural Science Foundation of China (Nos. 81971860 and 81772110) 2020-02-11 2020-03-30 2022-01-05 Copyright © Zhejiang University and Springer-Verlag GmbH Germany, part of Springer Nature 2020 2020 Journal of Zhejiang University-SCIENCE B (Biomedicine and Biotechnology) 07 21