Neutrophil-to-lymphocyte ratio is effective prognostic indicator for post-amputation patients with critical limb ischemia

A Systematic Review on the Role of Neutrophil to Lymphocyte Ratio in Limb Ischemia

BACKGROUND

Limb ischemia is a severe vascular condition that can lead to critical complications, endangering both limbs and lives. The goal of this research was to explore the role of neutrophil to lymphocyte ratio (NLR) in limb ischemia.

METHODS

From inception to June 8, 2022, PubMed/MEDLINE, Institute for Scientific Information Web of Science, and Scopus were searched for articles comparing NLR in limb ischemia to healthy individuals.

RESULTS

Finally, a total of 23 studies were included in the review. There was a direct link between NLR and critical limb ischemia (CLI) development in peripheral arterial disease patients. Elevated NLR levels predict a higher risk of CLI among peripheral arterial disease patients. Also, it was concluded that NLR is a dependable predictor of survival in patients with limb ischemia, and higher NLR readings are linked to decreased survival rates. Moreover, the risk of amputation is related to the level of NLR in CLI patients. However, based on the data, NLR is not a reliable indicator of sarcopenia in CLI patients. More research is needed to determine the relationship between NLR and response to treatment in CLI patients. Also, we recommend investigating the effect of each treatment on NLR level in these patients.

CONCLUSIONS

Our results provide evidence that NLR level is associated with risk of amputation and mortality in patients with limb ischemia. It is a promising biomarker that can be easily incorporated into clinical practice to assist in the prediction and prevention of CLI.

Neutrophil-to-lymphocyte ratio as a prognostic biomarker in patients with peripheral artery disease: A systematic review and meta-analysis

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR) is a simple and routinely obtained parameter reflecting systemic inflammation, including in peripheral artery disease (PAD).

METHODS

This systematic review aimed to assess the role of NLR as a prognostic biomarker in patients with PAD. A systematic search was conducted across PubMed, ScienceDirect, Web of Science, Scopus, ProQuest, EBSCO, and Cochrane. Random-effects meta-analysis was used to pool risk ratios, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). A bivariate model was used to generate summary receiver operating characteristics with the corresponding area under the curve (AUC).

RESULTS

This review included 5243 patients with PAD from nine eligible studies. High NLR corresponded to at least a twofold increased risk of all-cause mortality (ACM), major adverse limb events (MALE), and major adverse cardiovascular events (MACE). NLR's performance was good for predicting 1-year ACM (AUC 0.71 [95% CI: 0.59-0.79], sensitivity 58.2% [95% CI: 45.3-71.0], specificity 72.6% [95% CI: 65.6-79.62], PPV 41.0% [95% CI: 31.2-50.7], NPV 82.7% [95% CI: 74.1-91.3]) and 1-year MALE (AUC 0.78 [95% CI: 0.75-0.80], sensitivity 65.4% [95% CI: 41.6-89.2], specificity 77.7% [95% CI: 71.0-84.3], PPV 53.7% [95% CI: 47.3-60.1], NPV 83.91% [95% CI: 73.2-94.6]). However, these values tended to decrease as the follow-up duration extended, except for the pooled specificities, which exhibited the opposite pattern.

CONCLUSION

NLR emerges as a simple and cost-effective prognostic biomarker with decent performance for poor outcomes in patients with PAD (PROSPERO Registration No.: CRD42023486607).

A systematic review of the neutrophil to lymphocyte and platelet to lymphocyte ratios in patients with lower extremity arterial disease

Lower extremity arterial disease (LEAD) is caused by atherosclerotic plaque in the arterial supply to the lower limbs. The neutrophil to lymphocyte and platelet to lymphocyte ratios (NLR, PLR) are established markers of systemic inflammation which are related to inferior outcomes in multiple clinical conditions, though remain poorly described in patients with LEAD. This review was carried out in accordance with PRISMA guidelines. The MEDLINE database was interrogated for relevant studies. Primary outcome was the prognostic effect of NLR and PLR on clinical outcomes following treatment, and secondary outcomes were the prognostic effect of NLR and PLR on disease severity and technical success following revascularisation. There were 34 studies included in the final review reporting outcomes on a total of 19870 patients. NLR was investigated in 21 studies, PLR was investigated in two studies, and both NLR & PLR were investigated in 11 studies. Relating to increased levels of systemic inflammation, 20 studies (100%) reported inferior clinical outcomes, 13 (92.9%) studies reported increased disease severity, and seven (87.5%) studies reported inferior technical results from revascularisation. The studies included in this review support the role of elevated NLR and PLR as key components influencing the clinical outcomes, severity, and success of treatment in patients with LEAD. The use of these easily accessible, cost effective and routinely available markers is supported by the present review.

Characteristics of the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron BA.2 Subvariant in Jilin, China from March to May 2022

Background and Objectives

In the midst of the pandemic, new coronavirus mutants continue to emerge; the most relevant variant worldwide is omicron. Here, patients who recovered from the disease living in Jilin Province were analyzed to identify factors affecting the severity of omicron infection and to provide insights into its spread and early indication.

Methods

In this study, 311 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were divided into two groups. Data on the patients' demographic characteristics and laboratory tests, including platelet count (PLT), neutrophil count (NE), C-reactive protein (CRP), serum creatinine (SCR), and neutrophil-to-lymphocyte ratio (NLR), were collected. The biomarkers for moderate and severe coronavirus disease 2019 (COVID-19) and factors affecting the incubation period and time to subsequent negative nucleic acid amplification test (NAAT) were also investigated.

Results

Age, gender, vaccination, hypertension, stroke, chronic obstructive pulmonary disease (COPD)/chronic bronchitis/asthma, and some laboratory tests were statistically different between the two groups. In the receiver operating characteristic (ROC) analysis, PLT and CRP had higher area under the ROC curve values. In the multivariate analysis, age, hypertension, COPD/chronic bronchitis/asthma, and CRP were correlated with moderate and severe COVID-19. Moreover, age was correlated with longer incubation. In the Kaplan-Meier curve analysis, gender (male), CRP, and NLR were associated with longer time to subsequent negative NAAT.

Conclusions

Older patients with hypertension and lung diseases were likely to have moderate or severe COVID-19, and younger patients might have a shorter incubation. A male patient with high CRP and NLR levels might take more time to turn back negative in the NAAT.

Analysis of the factors affecting mortality after non-traumatic major lower extremity amputations

OBJECTIVE

The aim of this study was to evaluate the prognostic factors affecting mortality after major lower extremity amputations in patients with diabetes mellitus and peripheral vascular disease.

METHODS

For this retrospective study, 484 patients (345 male, 139 female) who were previously diagnosed with diabetes mellitus and peripheral vascular disease and underwent first-time nontraumatic major lower extremity amputations between January 2008 and January 2021 were included. The mean age of the patients was 64.2 ± 13.8 (20-114). In 32.4% of patients, peripheral vascular disease was the underlying cause, whereas diabetes mellitus was responsible for the etiology in 67.6% of patients. About 68.8% of patients had below-knee amputations, whereas 2.9% had bilateral below-knee amputations, 27.1% had above-knee amputations, and 1.2% had hip disarticulation performed. Gender, age, amputation level, amputation etiologies, Charlson comorbidity index, need for blood transfusion, and laboratory findings such as hemoglobin, platelet, albumin, erythrocyte sedimentation rate, C-reactive protein, sodium, potassium, and neutrophil to lymphocyte ratio levels were recorded preoperatively and at the time of discharge. Patients were grouped as died ≤1 month, ≤3 months, ≤6 months, and ≤12 months or alive.

RESULTS

Advanced age, female gender, high Charlson comorbidity index, blood transfusion requirement, proximal amputation level, preoperative low platelet, preoperative low albumin, and parameters such as low hemoglobin, low erythrocyte sedimentation rate, high sodium, low platelet, low albumin, high C-reactive protein, and high neutrophil to lymphocyte ratio at time of discharge were seen to have a statistically significant effect on mortality at 1 month, 3 months, 6 months, and 12 months postoperatively. Preoperative high C-reactive protein had a statistically significant effect on mortality at 1 and 3 months postoperatively, whereas low C-reactive protein had a statisti cally significant effect on mortality at 6 months postoperatively. High potassium at the time of discharge was associated with mortality at 6 and 12 months postoperatively.

CONCLUSION

This study has shown us that mortality rates are affected by modifiable parameters at the time of discharge such as hemoglo bin, sodium, potassium, platelet, and albumin, and normalization of these parameters before discharge could reduce the rates of mortality in the postoperative period.

LEVEL OF EVIDENCE

Level IV, Prognostic Study.

The relation between neutrophil/lymphocyte and platelet/lymphocyte ratios with mortality and limb amputation after acute limb ischaemia

OBJECTIVE

Acute limb ischaemia is still considered a significant event, with considerable early- and long-term amputation and mortality risk. Our study aims to investigate the predictive role of pre-operative neutrophil/lymphocyte and platelet/lymphocyte ratios in terms of mortality and amputation risk in patients with acute limb ischaemia.

METHODS

Pre-operative blood samples of all patients admitted with acute limb ischaemia were used to calculate neutrophil/lymphocyte and platelet/lymphocyte ratios. Population was subdivided into quartiles by platelet/lymphocyte ratio and neutrophil/lymphocyte ratio values, and Kaplan-Meier life tables were obtained for overall survival and limb salvage. The optimal neutrophil/lymphocyte ratio and platelet/lymphocyte ratio cut-offs were obtained from receiver operating characteristic curves with all-cause mortality and all kinds of amputation. Stepwise multivariate analysis was performed in order to identify independent risk and protective factors for mortality and amputations.

RESULTS

A total of 168 patients were included in the analysis. Receiver operating characteristic curves identified cut-off values for neutrophil/lymphocyte ratio and platelet/lymphocyte ratio: neutrophil/lymphocyte ratio ≥5.57 for mortality; neutrophil/lymphocyte ratio ≥6.66 and platelet/lymphocyte ratio ≥269.9 for all amputations. Kaplan-Meier analysis revealed that survival rate in group neutrophil/lymphocyte ratio <5.57 was 83.4%, 78.9%, 73.7%, and 59.8%, respectively, at 12, 24, 36, and 48 months; in neutrophil/lymphocyte ratio ≥5.57 group was 62.4%, 51.3%, 47.8, and 43.7%, respectively (p < 0.0001). Freedom from all amputations was significantly higher in case of neutrophil/lymphocyte ratio and platelet/lymphocyte ratio below the identified cut-off values (p < 0.0001). Neutrophil/lymphocyte ratio and platelet/lymphocyte ratio were found as independent risk factors.

CONCLUSION

Neutrophil/lymphocyte ratio and platelet/lymphocyte ratio are reliable markers for stratification of mortality and limb amputations in patients with acute limb ischaemia. The inexpensive nature and ready availability of these biomarkers' values reinforced their usefulness in everyday clinical practice.

Association of Neutrophil-Lymphocyte and Platelet-Lymphocyte Ratio with Adverse Events in Endovascular Repair for Abdominal Aortic Aneurysm

The association of chronic inflammatory markers with the clinical outcome after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) was investigated. We included 230 patients, treated electively with EVAR. The values of neutrophil–lymphocyte ratio (NLR) and platelet–lymphocyte ratio (PLR) were measured pre- and postoperatively. Any major adverse cardiovascular event (MACE) and acute kidney injury (AKI) were recorded. Adverse events occurred in 12 patients (5.2%). Seven patients suffered from MACE and five from AKI. Median NLR and PLR values were significantly increased after the procedure (NLR: from 3.34 to 8.64, p < 0.001 and PLR: from 11.37 to 17.21, p < 0.001). None of the patients or procedure characteristics were associated with the occurrence of either a MACE or AKI. Receiver operating characteristic curve analysis showed that postoperative NLR and PLR were strongly associated with AKI. A threshold postoperative NLR value of 9.9 was associated with the occurrence of AKI, with a sensitivity of 80% and specificity of 81%. A threshold postoperative PLR value of 22.8 was associated with the occurrence of AKI, with a sensitivity of 80% and specificity of 83%. Postoperative NLR and PLR have been associated with the occurrence of AKI after EVAR for AAA.

Blood Cell Count Biomarkers, Risk, and Outcomes of Ischemia-Related Lower Limb Amputations: Systematic Review

Lower limb amputations due to ischemia represent an important health care and social issue. However, there are currently no specific biomarkers able to predict the risk of amputation and postamputation complications and prognosis. We conducted a systematic review of studies investigating whether blood cell count indexes of systemic inflammation are linked to the risk and the outcome of lower limb amputations due to ischemia. Overall, in 22 studies involving 8832 patients selected for review, several blood cell count indexes, particularly the neutrophil lymphocyte ratio, showed some promise in terms of predicting amputations and general outcomes of conservative and surgical treatments, as well as postamputation complications and prognosis. However, largely due to methodological limitations, further prospective studies are required to establish the clinical utility and applicability of blood cell indexes in the routine management of patients with ischemia-related lower limb amputations.

Prognostic Significance of Preoperative Neutrophil-Lymphocyte Ratio in Vascular Surgery: Systematic Review and Meta-Analysis

OBJECTIVE

The global burden of surgical vascular disease is increasing and with it, the need for cost-effective, accessible prognostic biomarkers to aid optimization of peri-operative outcomes. The neutrophil-lymphocyte ratio (NLR) is emerging as a potential candidate biomarker for perioperative risk stratification. We therefore performed this systematic review and meta-analysis on the prognostic value of elevated preoperative NLR in vascular surgery.

METHODS

We searched Embase (Ovid), Medline (Ovid), and the Cochrane Library database from inception to June 2019. Screening was performed, and included all peer-reviewed original research studies reporting preoperative NLR in adult emergent and elective vascular surgical patients. Studies were assessed for bias and quality of evidence using a standardized tool. Meta-analysis was performed by general linear (mixed-effects) modelling where possible, and otherwise a narrative review was conducted. Between-study heterogeneity was estimated using the Chi-squared statistic and explored qualitatively.

RESULTS

Fourteen studies involving 5,652 patients were included. The overall methodological quality was good. Elevated preoperative NLR was associated with increased risk of long-term mortality (HR 1.40 [95%CI: 1.13-1.74], Chi-squared 60.3%, 7 studies, 3,637 people) and short-term mortality (OR: 3.08; 95%CI: 1.91-4.95), Chi-squared 66.59%, 4 studies, 945 people). Outcome measures used by fewer studies such as graft patency and amputation free survival were assessed via narrative review.

CONCLUSIONS

NLR is a promising, readily obtainable, prognostic biomarker for mortality outcomes following vascular surgery. Heterogeneity in patient factors, severity of vascular disease, and type of vascular surgery performed renders direct comparison of outcomes from the current literature challenging. This systematic review supports further investigation for NLR measurement in pre-vascular surgical risk stratification. In particular, the establishment of a universally accepted NLR cut-off value is of importance in real-world implementation of this biomarker.

Usefulness of Platelet-to-Lymphocyte Ratio as a Marker of Sarcopenia for Critical Limb Threatening Ischemia

BACKGROUND

Sarcopenia is a factor of poor prognosis for patients with critical limb threatening ischemia (CLTI), but its diagnosis requires imaging measurements and is time consuming. We investigated whether preoperative platelet-to-lymphocyte ratio (PLR) could be an easy and rapid marker of sarcopenia.

METHODS

Patients treated for CLTI between January 2019 and July 2019 were included in this single-center retrospective study. Sarcopenia was defined by a psoas muscle index (PMI) <5.5 cm²/m² in men, and <4.0 cm²/m² in women. PLR was calculated for all patients based on their systematic preoperative blood analysis. The diagnostic power of PLR was analyzed through a receiver operating characteristic (ROC) curve. Early outcomes of sarcopenic patients in terms of 30-day mortality and 30-day morbidity were retrieved.

RESULTS

Sixty-four patients were included in the study: 48 nonsarcopenic patients (mean PMI 7.34 cm²/m²; interquartile range [IQR] 6.58-8.01) and 16 sarcopenic patients (mean PMI 4.30 cm²/m²; IQR 3.45-5.17). No difference was found between both groups regarding patient demographics, clinical characteristics, cardiovascular risk factors, comorbidities, or revascularization modalities. PLR was significantly higher in the sarcopenic group (mean 332.1; IQR 158.2-320.7) compared with the nonsarcopenic group (mean 204.6; IQR 133.8-265.6) (P = 0.02). A PLR value ≥292.5 was shown to be a diagnostic marker for sarcopenia based on the ROC curve (sensitivity 31.3%, specificity 91.7%). Thirty-day mortality was 12.5% in the sarcopenic group and 2.1% in the nonsarcopenic group (P = 0.15); 30-day morbidity was 56.3% in the sarcopenic group and 10.4% in the nonsarcopenic group (P < 0.001).

CONCLUSIONS

PLR might help identifying a subgroup of CTLI patients associated with poor prognosis but does not seem appropriate to be used as a marker of sarcopenia given its low sensitivity.