Skip to content

Advertisement

  • Research article
  • Open Access
  • Open Peer Review

Neutrophil, lymphocyte and platelet ratio as a predictor of postoperative acute kidney injury in major abdominal surgery

  • 1Email author,
  • 1,
  • 1,
  • 1,
  • 2,
  • 1 and
  • 1
BMC Nephrology201819:320

https://doi.org/10.1186/s12882-018-1073-4

  • Received: 29 December 2017
  • Accepted: 5 October 2018
  • Published:
Open Peer Review reports

Abstract

Background

Surgery is one of the leading causes of acute kidney injury (AKI) in hospitalized patients. Major abdominal surgery has the second higher incidences of AKI, after cardiac surgery. AKI results from a complex interaction between hemodynamic, toxic and inflammatory factors. The pathogenesis of AKI following major abdominal surgery is distinct from cardiac and vascular surgery. The neutrophil, lymphocytes and platelets (N/LP) ratio has been demonstrated as an inflammatory marker and an independent predictor for AKI and mortality after cardiovascular surgery. The aim of this study was to evaluate the prognostic ability of the post-operative N/LP ratio after major abdominal surgery.

Methods

We cross-examined data of a retrospective analysis of 450 patients who underwent elective or urgent major nonvascular abdominal surgery at the Department of Surgery II of Centro Hospitalar Lisboa Norte from January 2010 to February 2011. N/LP ratio was determined using maximal neutrophil counts and minimal lymphocyte and platelet counts in the first 12 h after surgery. AKI was considered when developed within 48 h after surgery.

Results

One-hundred and one patients (22.4%) developed AKI. Patients with higher N/LP ratio had an increased risk of developing postoperative AKI (6.36 ± 7.34 vs 4.33 ± 3.36, p < 0.001; unadjusted OR 1.1 (95% CI 1.04–1.16), p = 0.001; adjusted OR 1.05 (95% CI 1.00–1.10), p = 0.048). Twenty-nine patients died (6.44%). AKI was an independent predictor of mortality (20.8 vs 2.3%, p < 0.0001; unadjusted OR 11.2, 95% CI 4. 8-26.2, p < 0.0001; adjusted OR 3.56, 95% CI 1.0 2-12.43, p = 0.046). In a multivariate analysis higher N/LP ratio was not associated with increased in-hospital mortality.

Conclusion

Postoperative N/LP ratio was independently associated with AKI after major abdominal surgery, although there was no association with in-hospital mortality.

Keywords

  • Acute kidney injury
  • Inflammation
  • Neutrophil
  • Lymphocyte
  • Platelets

Background

Postoperative acute kidney injury (AKI) accounts for up to 40% AKI cases in hospitalized patients [1] and has been associated with progression to chronic kidney disease (CKD), increased cardiovascular events, increased length of hospital stays and increased in-hospital and long-term mortality [25].

The incidence of AKI in surgical patients is variable depending on the surgical setting, with higher rates being reported after cardiac, general, and thoracic surgeries. [5, 6] Nevertheless, the pathogenesis of AKI following major abdominal surgery appears to be distinct from that of cardiac and vascular surgery.

In fact, AKI after major abdominal surgery is multifactorial and results from an intricate interaction of hemodynamic, toxic and inflammatory factors. [7, 8] Also, the role of a pro-inflammatory response after abdominal surgery resulting from the post-ischemic or reperfusion period has been increasingly recognized in AKI [912] and appears to negatively impact other organs. [9].

Given the short and long-term impact of post-operative AKI, it is highly important to detect predictors and early markers of AKI in this setting in order to timely prevent and manage this complication. [8].

The neutrophil-lymphocyte ratio (N/L ratio) is a low-cost biomarker of systemic inflammation, easily calculated from a complete blood cell count. [13].

Its role has a prediction tool in cardiovascular mortality [14], survival in malignancies [15], postoperative outcome [16], and progression of CKD [17] has been previously demonstrated. Furthermore, in recent studies it has been studied as an early predictor for AKI in the emergency setting [13], in septic patients [18], contrast induced-AKI [19] and in cardiovascular surgery [20]. In cardiovascular surgery it was also associated with one-year mortality [20]. More recently, the addition of platelet count to this ratio increased predictive ability of AKI compared to N/L ratio or platelet nadir after cardiovascular surgery [21].

However, the prognostic ability of the neutrophils to lymphocytes and platelets ratio (N/LP ratio) has not previously been evaluated in AKI after major abdominal surgery.

The aim of this study was to evaluate the prognostic ability of the post-operative N/LP ratio after major abdominal surgery. For this purpose, we cross-examined data from a retrospective study in which we studied a cohort of patients undergoing major nonvascular abdominal surgery in which the objective was to evaluate the incidence, risk factors and outcome of AKI [22].

Methods

Study design

This was a cross-examination of a retrospective analysis of clinical data of patients who underwent elective or urgent major nonvascular abdominal surgery at the Department of Surgery II of Centro Hospitalar Lisboa Norte from January 2010 to February 2011. [22] The study was approved by the Ethical Committee at the Centro Hospitalar Lisboa Norte, EPE, in agreement with institutional guidelines. Informed consent was waived by the Ethical Committee due to the retrospective and non-interventional nature of the study.

Participants

All patients aged 18 or older who underwent urgent or elective major nonvascular abdominal surgery admitted to the Post-Anesthesia Care Unit (PACU) of the Department of Surgery II of Centro Hospitalar Lisboa Norte from January 2010 to February 2011 were eligible for this study.

Major abdominal surgery was defined as intraperitoneal approach performed under general anesthesia, with a predictable length of hospital stay of at least two days. [23, 24] For patients with more than one surgery, only the first procedure was considered. In patients with multiple hospital admissions, only the first one was considered.

Exclusion criteria included: CKD patients already on renal replacement therapy; patients who underwent renal replacement therapy the week before surgery; patients who had less than two determinations of SCr during hospital stay, and patients who were discharged from hospital less than two days after the procedure. After analysis of the PACU patient admission register, 492 patients were selected as potentially eligible. Of these, 42 were excluded. [22] (Fig. 1).
Fig. 1
Fig. 1

Flow-chart of patient selection

Variables

All variables were collected from electronic and hand-written patient clinical records, including intraoperative data recorded by the anaesthesiologist. All scores and formulas were calculated based on raw clinical data.

The analyzed variables included demographic characteristics (age, gender, and ethnicity), preoperative clinical characteristics, physical status according to the American Society of Anaesthesiologists (ASA) score [25], preoperative serum hemoglobin and SCr, nature of the procedure (elective or urgent), duration of anaesthesia, intraoperative blood pressure, use of fluids (colloids - hydroxyethyl starch, gelatin and albumin 5%; crystalloids - sodium chloride 0.9%, Ringer’s lactate and polyelectrolyte solution), intraoperative blood transfusions and use of vasoactive drugs, postoperative AKI and mortality.

Regarding preoperative clinical characteristics, the comorbidities registered were diabetes mellitus (diagnosed according to the American Diabetes Association criteria [26], hypertension (diagnosed according to the seventh report of the Joint National Committee [27], cardiovascular disease (including chronic heart failure, cardiac ischemic disease and history of transient ischemic attack or stroke), chronic obstructive pulmonary disease (COPD) including emphysema and chronic bronchitis, and malignancy. For cardiovascular disease and COPD, indication on clinical records of previous diagnosis was considered sufficient. To estimate the glomerular filtration rate (eGFR) the 4-variable Modification of Diet in Renal Disease formula was used [28].

Pertaining intraoperative variables, systolic and diastolic blood pressure (SBP and DBP, respectively) were recorded automatically every 5 min and intraoperative mean arterial pressure (MAP) was calculated as [(2xDBP) + SBP]/3. When available, invasive measurements were preferred to non-invasive ones. Intraoperative hypotension (IOH) was defined as intraoperative MAP inferior to 65 mmHg and the number of episodes of IOH was registered. Blood transfusions were done in patients with active bleeding or hemodynamically unstable or when the serum hemoglobin level was below the 7 to 8 g/dl range [29] or, in older patients and in patients with coronary artery disease, bellow 10 g/dl.

Definitions

In this analysis, only AKI developing in the first 48 h after surgery was considered to be attributed to the surgical procedure. AKI was diagnosed using the Kidney Disease Improving Global Outcome (KDIGO) classification based on both serum creatinine (SCr) and urine output (UO) criteria, as an increase in serum creatinine (SCr) of 0.3 mg/dl within 48 h-periods, or an increase in SCr of 1.5 times baseline, which is known or within the prior 7 days, or a decrease in urinary output to less than 0.5 ml/kg/h for 6 h [30]. Pre-operative SCr was considered baseline SCr.

The neutrophil, lymphocyte and platelet counts were measured in the clinical laboratory of our hospital in the first 12 h after surgery. Maximal neutrophil counts and minimal lymphocyte and platelet counts were considered. Postoperative N/LP ratio was calculated as: (Neutrophil count × 100)/(Lymphocyte count x Platelet count).

Outcomes

Development of AKI, in-hospital mortality and length of hospital and ICU stay were assessed.

Statistical methods

Continuous variables were presented as the mean ± standard deviation and categorical variables as the total number and percentage of cases for each category. Normality of variables was assessed using the Kolmogorov-Smirnov test. After grouping participants according to the development of postoperative AKI, the variables of both groups were compared using Student’s t-test for normally distributed continuous variables and chi square test for categorical variables.

The discriminatory ability for N/LP ratio to predict AKI was determined using the receiver operating characteristic (ROC) curve. A cut-off value was defined as that with the highest validity.

Firstly, all variables underwent univariate analysis to determine statistically significant factors that may have contributed to AKI and mortality. Only variables which significantly differed between AKI and non-AKI groups were used in the multivariate analysis using the logistic regression method. An adjusted multivariate analysis to pre-operative, intra-operative and post-operative factors was conducted. Data were expressed as Odds ratios (OR) with 95% confidence intervals (95% CI). Sensitive analysis excluding septic patients and adjusting for pre-operative, intra-operative and post-operative factors were conducted.

Statistical significance was defined at a p-value (p) < 0.05. Analyses were performed with the statistical software package SPSS 21.0 for Windows.

Results

Participants

We focused on a cohort of 450 patients. Demographic, preoperative, intraoperative and postoperative patient variables and outcomes are described in Tables 1 and 2.
Table 1

Patient’s baseline characteristics and comparison according to the development of AKI

Characteristic

Baseline (n = 450)

KDIGO

No AKI (n = 349)

AKI (n = 101)

p value

Age (years) - mean ± SD

62 ± 16

60.6 ± 15.7

71.1 ± 13.2

< 0.0001

Gender (Male) – n (%)

227 (50.4)

168 (48.1%)

59 (58.4%)

0.069

Race (Caucasian) – n (%)

431 (95.8)

335 (96)

96 (95)

0.679

Co-morbidities – n (%)

 Hypertension

225 (50)

168 (48.1)

57 (56.4)

0.142

 Diabetes

84 (18.7)

62 (17.8)

22 (21.8)

0.001

 CVD

29 (6.4)

13 (3.7)

16 (15.8)

< 0.0001

 COPD

25 (5.6)

13 (3.7)

12 (11.9)

< 0.0001

 Cirrhosis

9 (2)

7 (2)

2 (1.9)

0.987

 Neoplasia

190 (42.2)

135 (38.7)

55 (54.5)

0.005

SAPS II - n (%)

23 (17.4)

19.1 (10.9)

34.3 (21.3)

< 0.0001

Baseline SCr (mg/dl) - mean ± SD

1 ± 0.5

0.9 ± 0.4

1.2 ± 0.7

< 0.0001

Baseline eGFR (ml/min/1.73 m2) - mean ± SD

80.3 ± 1.1

92.5 ± 1.2

60.5 ± 1.3

< 0.0001

Hemoglobin (g/dl) - mean ± SD

11.1 ± 1.7

11.3 ± 1.7

10.5 ± 1.6

< 0.0001

Post-operative neutrophils - mean ± SD

9.2 ± 4.2

9.39 ± 4.35

8.61 ± 3.57

0.102

Post-operative lymphocytes - mean ± SD

1.2 ± 0.8

1.26 ± 0.90

0.97 ± 0.61

0.003

Post-operative platelets - mean ± SD

243.1 ± 105.2

245.95 ± 104.94

233.05 ± 106.2

0.279

Post-operative NL/P - mean ± SD

4.78 ± 4.64

4.33 ± 3.36

6.36 ± 7.34

< 0.001

Post-operative NL/P > 4.86– n (%)

154 (34.2)

113 (32.4)

54 (53.5)

< 0.001

Pre-operative sepsis – n (%)

70 (15.6)

39 (11.2)

31 (30.7)

< 0.001

Mechanical ventilation – n (%)

11 (2.4)

6 (1.7)

5 (4.9)

0.064

Vasopressors – n (%)

80 (17.7)

55 (15.8)

25 (24.8)

0.037

Fluid balance in the first 48 h (L) - mean ± SD

1.48 ± 1.43

1.40 ± 1.42

1.72 ± 1.44

0.046

LOS in hospital (days) - mean ± SD

12 ± 12.6

11.1 ± 11.3

15.2 ± 16.1

0.004

LOS in ICU (days) - mean ± SD

20 ± 4.4

3.6 ± 7.1

6.9 ± 11.7

< 0.0001

Hospital mortality – n (%)

29 (6.4)

8 (2.3)

21 (20.8)

< 0.0001

Abbreviations: CVD cardiovascular disease, COPD chronic obstructive pulmonary disease, SCr serum creatinine, eGFR estimated glomerular filtration rate, NL/P neutrophil-lymphocyte and platelet ratio, SD standard deviation; LOS length of stay; ICU intensive care unit

Table 2

Univariate and multivariate analysis of factors predictive of outcomes

 

AKI

Mortality

Unadjusted OR (95% CI)

P-value

Adjusted OR (95% CI)

P-value

Unadjusted OR (95% CI)

P-value

Adjusted OR (95% CI)

P-value

Preoperative characteristics

 Age

1.05 (1.04–1.07)

< 0.0001

1.04 (1.0 2-1.06)

< 0.0001

1.1 (1.06–1.2)

< 0.0001

1.10 (1.03–1.17)

0.003

 Male

1.5 (0.9–2.4)

0.07

  

1.1 (0.5–2.2)

0.887

  

 Caucasian

0.8 (0.3–2.3)

0.680

  

1.3 (1.2–9.7)

0.831

  

 Diabetes

0.046 (0.01–0.15)

0.363

  

0.01 (0.01–0.05)

0.839

  

 CVD

0.35 (0.2–0.5)

< 0.0001

0.23 (0.089–0.38)

0.002

0.115 (0.023–0.21)

0.14

  

 COPD

0.31 (0. 15-0.48)

< 0.0001

0.22 (0.07–0.37)

0.005

0.059 (0.001–0.158)

0.245

  

 Solid malignancy

1.9 (1. 2-2.9)

0.005

1.47 (0.85–2.54)

0.174

1.5 (0. 7-3.2)

0.287

  

 ASA physical status IV/V

2.5 (1. 2-4.9)

0.01

1.16 (0.49–2.78)

0.732

15.4 (6. 7-35.6)

< 0.0001

10.71 (2.90–39.54)

< 0.0001

 Hemoglobin (g/dL)

0.8 (0. 7-0.9)

< 0.0001

0.97 (0.82–1.14)

0.675

0.63 (0. 5-0.8)

< 0.0001

0.73 (0.51–1.04)

0.077

 Baseline SCr (mg/dL)

2.3 (1. 5-3.4)

< 0.0001

1.28 (0.78–2.12)

0.327

2.3 (1. 3-3.9)

0.003

0.56 (0. 24-1.30)

0.174

 Preoperative sepsis

3.52 (2.06–6.03)

< 0.0001

1.30 (0.63–2.66)

0.480

19.9 (8. 37-47.43)

< 0.0001

5.23 (1.46–18.75)

0.011

 Urgency surgery

0.3 (0. 8-2.1)

0.368

  

4.2 (1. 9-8.9)

< 0.0001

1.32 (0. 33-5.22)

0.693

Intraoperative characteristics

 Duration of anesthesia

1.02 (1-1.05)0.024

0.024

1.00 (1.00–1.00)

0.156

1.00 (0.997–1.004)

0.845

  

 Hypotension episodes

1.2 (1. 1-1.4)

0.001

1.10 (0.95–1.26)

0.203

1.46 (1. 27-1.69)

< 0.0001

1.52 (1. 16-1.98)

0.002

 Crystalloids with colloids

3 (1. 8-5)

< 0.0001

1.80 (0.97–3.33)

0.062

6.05 (1.80–20.29)

0.004

2.61 (0.43–15.68)

0.296

 Fluid balance

1.00 (1.00–1.001)

0.048

  

1.00 (1.00–1.001)

< 0.0001

  

 Erythrocytes (per unit)

3.7 (2. 4-5.8)

< 0.0001

2.27 (1.45–3.55)

< 0.0001

2.25 (1.49–3.40)

< 0.0001

1.22 (0.68–2.20)

0.508

 Vasoactive drugs use

1.8 (1. 1-3)

0.039

1.10 (0.58–2.11)

0.769

5.87 (2.70–12.74)

< 0.0001

4.08 (1. 21-13.78)

0.023

Post-operative characteristics

 NL/P (per point increase)

1.1 (1.04–1.16)

0.001

1.05 (1.00–1.10)

0.048

1.04 (0.995–1.106)

0.078

0.95 (0.84–1.08)

0.463

 NL/P > 4.86

2.4 (1.53–3.77)

< 0.0001

1.72 (1.04–2.87)

0.036

2.56 (1. 19-5.5)

0.178

1.16 (0. 38-3.5)

0.798

 AKI

    

11.19 (4.78–27.18)

< 0.0001

3.56 (1.02–12.43)

0.046

In the first 48 h after surgery, 101 patients (22.4%) developed AKI. Patients with post-operative AKI were older (p < 0.001) and were more likely to have preexisting ischemic heart disease (p = 0.001), congestive heart failure (p = 0.008), cerebrovascular disease (p < 0.001), COPD (p < 0.001) and solid malignancies (p = 0.005) and to be ASA IV/V (p = 0.009). Also, these patients had lower preoperative hemoglobin (Hb) values (p < 0.001), higher preoperative SCr (p < 0.001) and preoperative sepsis (p < 0.001). Longer duration of anesthesia (p = 0.021), intraoperative hypotension episodes (p < 0.001), intraoperative colloids and crystalloids as compared with crystalloids without colloids (p < 0.001), intraoperative erythrocytes transfusions (p < 0.001), and intraoperative vasoactive drugs (p = 0.037) were also associated with AKI.

Post-operative N/LP ratio and AKI

Patients with higher N/LP ratio had an increased risk of developing postoperative AKI (6.36 ± 7.34 vs 4.33 ± 3.36, p < 0.001; unadjusted OR 1.1 (95% CI 1.04–1.16), p = 0.001; adjusted OR 1.05 (95% CI 1.00–1.10), p = 0.048).

In a multivariate analysis only older age (p < 0.001), CVD (p = 0.002), COPD (p = 0.005), NL/P ratio (p = 0.048) and intraoperative erythrocytes transfusions (p < 0.001) were associated with AKI. After a sensitive analysis in which septic patients were excluded, a higher NL/P was still associated with AKI development (6.29 ± 8.1 vs 4.14 ± 3.01, p < 0.001; unadjusted OR 1.11 (95% CI 1.036–1.189), p < 0.001; adjusted OR 1.078 (95% CI 1.01–1.15), p = 0.025). An adjusted multivariate analysis to pre-operative, intra-operative and post-operative factors was conducted, in which a higher N/LP ratio remained as an independent predictor of increased risk of developing postoperative AKI (adjusted OR 1.012 (95% CI 1.003–1.021), p = 0.007).

A ROC curve was produced to assess the discriminative ability of N/LP ratio for AKI. The AUC for AKI prediction was of 0.606, 95% CI (0.559–0.651). (Fig. 2) The optimal cutoff was assessed to be > 4.86, which has a sensitivity of 52.5% and specificity of 71.1% with a positive predictive value of 1.81 and negative predictive value of 0.67. In a multivariate analysis, NLP > 4.86 was associated with an increased risk of postoperative AKI (adjusted OR 1.72 (95% CI 1.04–2.87), p = 0.036).
Fig. 2
Fig. 2

AUC of the risk model for the prediction of AKI with NL/P ratio

Post-operative N/LP ratio and mortality

In this cohort 29 patients died, and AKI was an independent predictor of mortality (20.8 vs 2.3%, p < 0.0001; unadjusted OR 11.2, 95% CI 4. 8-26.2, p < 0.0001; adjusted OR 3.56, 95% CI 1.02–12.43, p = 0.046). In a multivariate analysis higher N/LP ratio was not associated with increased in-hospital mortality.

Discussion

In this retrospective cohort, we demonstrated that a higher postoperative N/LP ratio was independently associated with AKI after major abdominal surgery, whereas there was no association with in-hospital mortality.

In past years, many studies have revealed the important role of inflammation in the pathogenesis of AKI, and in particular in postoperative AKI [810].

Release of endotoxin load from gut ischemia, impaired visceral perfusion, and portal endotoxemia activate a pro-inflammatory response during abdominal surgery. [11] This results in endothelial injury and consequently vasoconstriction, microvascular sludging, and congestion with leukocytes. [31] Additionally, the postischemia or reperfusion period induces further tubular damage produced by reactive oxygen species and tissue inflammation. [10, 11, 31] The immune activation following AKI results in systemic inflammatory changes. [32].

Platelets have a central role in maintaining hemostasis and coagulation. [33] Recent data supports the present role of platelets in inflammation. [33] Their interaction with neutrophils, monocytes, and lymphocytes modulates both innate and adaptive immune responses. [34] Platelets adhere to damaged endothelium and recruit leukocytes to sites of injury. [35] Moreover, it has been shown that the microvascular sludging with leukocytes and activated platelets is critical in the pathogenesis of postoperative AKI. [31, 36].

Postoperative thrombocytopenia might result from this microvascular sludging and platelet consumption. In cardiac surgery the association of postoperative thrombocytopenia and AKI has been demonstrated. [36] In fact, the extent of the platelet count decrease was associated with the severity of AKI and hospital mortality. [36] Thrombocytopenia has also been associated with AKI and mortality in non-surgical settings. [37, 38] Nonetheless, thrombocytopenia is also a marker for critically ill patients and may reflect an underlying disease. [33].

The N/L ratio has already been established as an important marker for inflammation in AKI. [13, 1820] In order to combine the predictive ability of the N/L ratio and platelet count, Koo et al. developed the N/LP ratio in the setting of postoperative AKI after cardiovascular surgery. [21] In a multivariate analysis, the ratio was independently associated with AKI differently than separate N/L ratio and platelet nadir. [21] Their data also reports an association between the N/LP ratio and short and long-term mortality. [21].

In our cohort of AKI after major abdominal surgery, N/LP ratio was independently associated with AKI, however no association with mortality was demonstrated. These results may reflect the small sample of our cohort and further study is necessary to apply this ratio as a mortality predictor.

The main strength of our study is that this is the first to examine the association between N/LP and AKI after major abdominal surgery, confirming the impact of inflammation in this setting. Also, some important variables were accounted for in our study. Transfusion amount has been reported as a predictor for postoperative AKI [22], nevertheless, the association of the ratio with AKI remained significant after adjustment for these variables. We used a marker of inflammation and accounted for septic patients prior to the surgery, in order to assess only the inflammation associated to surgery related AKI, and the N/LP ratio remained a significant predictor of AKI.

However, there are some important limitations. Firstly, the single-center nature of our study which limits generalizability. Second, the retrospective design with a moderately small cohort of patients which may have overlooked some potential confounders with prognostic importance. Finally, the predictive value of our ROC curve is modest, nevertheless indicative of a significant association of the variables, meaning that further validation of this ratio is required.

Conclusion

In conclusion, we confirmed that the postoperative N/LP ratio was independently associated with AKI after major abdominal surgery, although there was no association with in-hospital mortality in our cohort. The assessment of this ratio is straightforward from routine blood analysis in postoperative patients and can prove useful in identifying patients at risk for AKI.

Declarations

Availability of data and materials

Please contact author for data requests.

Authors’ contributions

JG and JAL made substantial contributions to the study concept and design, analysis and interpretation of data, and were involved in drafting the manuscript and revising it critically for important intellectual content. JG, JAF, JMD, JM, RR participated in the acquisition of data. SJ was involved in the critical revision of the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

The study was approved by the Ethical Committee at the Centro Hospitalar Lisboa Norte, EPE, in agreement with institutional guidelines. Informed consent was waived by the Ethical Committee due to the retrospective and non-interventional nature of the study.

Consent for publication

Not applicable.

Competing interests

There is no conflict of interest. The results presented in this paper have not been published previously in whole or part, except in abstract format.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Division of Nephrology and Renal Transplantation, Department of Medicine, Centro Hospitalar Lisboa Norte, EPE, Av. Prof. Egas Moniz, 1649-035 Lisbon, Portugal
(2)
Department of Surgery, Centro Hospitalar Lisboa Norte, EPE, Av. Prof. Egas Moniz, 1649-035 Lisbon, Portugal

References

  1. Calvert S, Shaw A. Perioperative acute kidney injury. Perioper Med. 2012;4(1):6.View ArticleGoogle Scholar
  2. Biteker M, Dayan A, Tekkesin AI, et al. Incidence, risk factors, and outcomes of perioperative acute kidney injury in noncardiac and nonvascular surgery. Am J Surg. 2014;207:53–9.View ArticleGoogle Scholar
  3. Ryden L, Sartipy U, Evans M, Holzmann MJ. Acute kidney injury after coronary artery bypass grafting and long-term risk of end-stage renal disease. Circulation. 2014;130:2005–11.View ArticleGoogle Scholar
  4. Hobson C, Ozrazgat-Baslanti T, Kuxhausen A, et al. Cost and mortality associated with postoperative acute kidney injury. Ann Surg. 2015;261:1207–14.View ArticleGoogle Scholar
  5. Grams ME, Sang Y, Coresh J, et al. Acute kidney injury after major surgery: a retrospective analysis of veteran’s health administration data. Am J Kidney Dis. 2016;67(6):872–80.View ArticleGoogle Scholar
  6. Thakar CV. Perioperative acute kidney injury. Adv Chronic Kidney Dis. 2013;20:67–75.View ArticleGoogle Scholar
  7. Sear J. Kidney dysfunction in the postoperative period. Br J Anaesth. 2005;95(1):20–32.View ArticleGoogle Scholar
  8. Carmichael P, Carmichael AR. Acute renal failure in the surgical setting. ANZ J Surg. 2003;73:144–53.View ArticleGoogle Scholar
  9. Grams ME, Rabb H. The distant organ effects of acute kidney injury. Kidney Int. 2012;81:942–8.View ArticleGoogle Scholar
  10. Kerrigan CL, Stotland MA. Ischemia reperfusion injury: a review. Microsurgery. 1993;14:165–75.View ArticleGoogle Scholar
  11. Welborn MB, Oldenburg HS, Hess PJ, et al. The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair. Crit Care Med. 2000;28:3191–7.View ArticleGoogle Scholar
  12. Gobe G, Willgoss D, Hogg N, Schoch E, Endre Z. Cell survival or death in renal tubular epithelium after ischemia- reperfusion injury. Kidney Int. 1999;56:1299–304.View ArticleGoogle Scholar
  13. Abu Alfeilat M, Slotki I, Shavit L. Single emergency room measurement of neutrophil/lymphocyte ratio for early detection of acute kidney injury (AKI). Intern Emerg Med. 2017. https://doi.org/10.1007/s11739-017-1715-8.View ArticleGoogle Scholar
  14. Azab B, Zaher M, Weiserbs KF, et al. Usefulness of neutrophil to lymphocyte ratio in predicting short- and long-term mortality after non-ST-elevation myocardial infarction. Am J Cardiol. 2010;106:470–6.View ArticleGoogle Scholar
  15. Chua W, Charles KA, Baracos VE, Clarke SJ. Neutrophil/lymphocyte ratio predicts chemotherapy outcomes in patients with advanced colorectal cancer. Br J Cancer. 2011;104:1288–95.View ArticleGoogle Scholar
  16. Forget P, Dinant V, De Kock M. Is the neutrophil-to lymphocyte ratio more correlated than C-reactive protein with postoperative complications after major abdominal surgery? PeerJ. 2015;13(3):e713.View ArticleGoogle Scholar
  17. Kocyigit I, Eroglu E, Unal A, et al. Role of neutrophil/lymphocyte ratio in prediction of disease progression in patients with stage-4 chronic kidney disease. J Nephrol. 2013;26:358–65.View ArticleGoogle Scholar
  18. Yilmaz H, Cakmak M, Inan O, Darcin T, Akcay A. Can neutrophil-lymphocyte ratio be independent risk factor for predicting acute kidney injury in patients with severe sepsis? Ren Fail. 2015;37(2):225–9.View ArticleGoogle Scholar
  19. Yuan Y, Qiu H, Hu X, et al. Predictive value of inflammatory factors on contrast-induced acute kidney injury in patients who underwent an emergency percutaneous coronary intervention. Clin Cardiol. 2017;40(9):719–25.View ArticleGoogle Scholar
  20. Kim WH, Park JY, Ok SH, Shin IW, Sohn JT. Association between the neutrophil/lymphocyte ratio and acute kidney injury after cardiovascular surgery: a retrospective observational study. Medicine (Baltimore). 2015;94(43):e1867.View ArticleGoogle Scholar
  21. Koo CH, Eun Jung D, Park YS, et al. Neutrophil, Lymphocyte, and Platelet Counts and Acute Kidney Injury After Cardiovascular Surgery. J Cardiothorac Vasc Anesth. 2018;32(1):212–22.View ArticleGoogle Scholar
  22. Teixeira C, Rosa R, Rodrigues N, et al. Acute kidney injury after major abdominal surgery: a retrospective cohort analysis. Crit Care Res Pract. 2014;2014:132175.PubMedPubMed CentralGoogle Scholar
  23. Small RG. Witt RE; major and minor surgery. JAMA. 1965;191:180–2.View ArticleGoogle Scholar
  24. Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100(10):1043–9.View ArticleGoogle Scholar
  25. ASA; New classification of physical status. Anesthesiology. 1963;24:111.Google Scholar
  26. ADA; Standards of medical care in diabetes - 2009. Diabetes Care 2009; 32(Suppl 1):S13–S61.Google Scholar
  27. Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure: the JNC 7 report. JAMA. 2003;289(19):2560–72.View ArticleGoogle Scholar
  28. Levey AS, Coresh J, Greene T, et al. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med. 2006;145(4):247–54.View ArticleGoogle Scholar
  29. Carson JL, Carless PA, Hebert PC. Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion. Cochrane Database Syst Rev. 2012;4:CD002042.PubMed CentralGoogle Scholar
  30. KDIGO. Clinical practice guideline for acute kidney injury. Kidney Int. 2012;2:S1–138.View ArticleGoogle Scholar
  31. Devarajan P. Update on mechanisms of ischemic acute kidney injury. J Am Soc Nephrol. 2006;17:1503–20.View ArticleGoogle Scholar
  32. Bonventre JV, Zuk A. Ischemic acute renal failure: an inflammatory disease? Kidney Int. 2004;66:480–5.View ArticleGoogle Scholar
  33. Li Z, Yang F, Dunn S, Gross AK, Smyth SS. Platelets as immune mediators: their role in host defense responses and sepsis. Thromb Res. 2011;127:184–8.View ArticleGoogle Scholar
  34. Lapchak PH, Kannan L, Ioannou A, et al. Platelets orchestrate remote tissue damage after mesenteric ischemia-reperfusion. Am J Physiol Gastrointest Liver Physiol. 2012;302:G888–97.View ArticleGoogle Scholar
  35. Kornerup KN, Salmon GP, Pitchford SC, Liu WL, Page CP. Circulating platelet-neutrophil complexes are important for subsequent neutrophil activation and migration. J Appl Physiol. 2010;109:758–67.View ArticleGoogle Scholar
  36. Kertai MD, Zhou S, Karhausen JA, et al. Platelet counts, acute kidney injury, and mortality after coronary artery bypass grafting surgery. Anesthesiology. 2016;124(2):339–52.View ArticleGoogle Scholar
  37. Nie S, Feng Z, Xia L, et al. Risk factors of prognosis after acute kidney injury in hospitalized patients. Front Med. 2017;11(3):393–402.View ArticleGoogle Scholar
  38. Chao CT, Tsai HB, Chiang CK, et al. Thrombocytopenia on the first day of emergency department visit predicts higher risk of acute kidney injury among elderly patients. Scand J Trauma Resusc Emerg Med. 2017;25(1):11.View ArticleGoogle Scholar

Copyright

© The Author(s). 2018

Advertisement