Ekrem Aksu1, Deniz Avcı2, Enes Çelik1, Bayram Öztürk1, Mehmet Buğra Bozan3, Kemal Göçer4, Ahmet Çağrı Aykan1

1Department of Cardiology, Faculty of Medicine, University of Kahramanmaras Sutcu Imam, Kahramanmaras, Turkey
2Department of Internal Medicine, Kayseri Training and Research Hospital, Kayseri, Turkey
3Department of General Surgery, Faculty of Medicine, University of Kahramanmaras Sutcu Imam, Kahramanmaras, Turkey
4Department of Cardiology, Necip Fazıl City Hospital, Kahramanmaras, Turkey

Keywords: Non-ST elevation myocardial infarction; invasive treatment; neutrophil to lymphocyte ratio; systemic immune-inflammation index.


Introduction: The non-invasive approach has become the first choice for the acute non-ST elevation myocar- dial infarction-acute coronary syndrome (NSTEMI-ACS) during the Coronavirus Disease-2019 (COVID-19) pandemic. However, most of these patients require interventional treatment. In this study, the possible role of hematological inflammatory markers in differentiating medium-high risk NSTEMI-ACS patients according to the GRACE risk classification in need of interventional treatment was investigated.

Patients and Methods: Patients who underwent coronary angiography with the diagnosis of NSTEMI-ACS in a tertiary cardiology clinic between January 2018 and December 2019 were included in the study, which was designed as a retrospective cohort study. NSTEMI-ACS patients (n= 276), except for patients with exclu- sion criteria (n= 32), were divided into two groups as those in need of invasive treatment (n= 217) and medical treatment (n= 59) according to the results of coronary angiography. The hematological inflammatory markers were compared between groups.

Results: Neutrophil to lymphocyte ratio (NLR) (AUC: 0.637, 95% CI: 0.563-0.712, p= 0.001) and systemic immune-inflammation index (SII) (AUC: 0.622, 95% CI: 0.545-0.699, p= 0.004) predicted the requirement of interventional treatment in NSTEMI-ACS.

Conclusion: It is unclear whether the NLR and SII elevation, which may be a predictor of the need for inva- sive treatment, is a cause or a consequence of the pathophysiological process in patients with NSTEMI-ACS. However, elevated NLR and SII values can help distinguish NSTEMI-ACS patients who need invasive treat- ment during the COVID-19 pandemic. The results of this study, show the need for large-sized studies to de- termine the ideal cut-off point of NLR and SII levels in determining the treatment strategy for NSTEMI-ACS


Non-ST elevation myocardial infarction-acute coronary syndrome (NSTEMI-ACS) is one of the cardiac emergencies where early diagnosis and treatment are important. In the guidelines, diagnostic coronary angiography is recommended within 24 hours at the latest in patients with NSTEMI-ACS(1). However, in the national consensus statement published in the period of Coronavirus Disease-2019 (COVID-19), non-invasive treatment was recommended as an alternative therapy in patients with non-very high risk NSTEMI-ACS(2,3). Unfortunately, risk scoring systems are not sufficient to differentiate these patients. Therefore, it is important to discover markers that can be used to differentiate NSTEMI-ACS patients with increased invasive treatment during the COVID-19 pandemic.

Inflammation plays an active role in the development and progression of atherosclerotic plaque in the coronary artery. It has been reported that coronary artery patients with severe atherosclerotic involvement and high mortality rates may be distinguished with the help of hematological markers closely related to inflammation(4,5). To the best of our knowledge, there is a lack of literature on the correlation between the need for invasive treatment strategy and the hematological markers in patients diagnosed with NSTEMI-ACS.

In this study, the potential role of hematologic inflammatory markers in differentiating those requiring invasive treatment in patients with medium-high risk NSTEMI-ACS according to the Global Registry of Acute Coronary Events (GRACE) risk classification was investigated(6).

Materials and Methods

The study was designed as a retrospective cohort study. Study data were obtained from medical records. Between January 2018 and December 2019, patients treated with a diagnosis of NSTEMI-ACS in the cardiology clinic of a tertiary hospital were consecutively evaluated. NSTEMI-ACS was defined as ischemic chest pain with troponin-I levels > 0.01 ng/mL and non-ST segment elevation on 12-lead chest electrocardiography (ECG).

Inclusion criterias: Patients who do not have exclusion criteria and who underwent coronary angiography with the diagnosis of NSTEMI-ACS.

Exclusion criterias: Being under the age of 18, chest pain that persists despite medication, hemodynamic instability, fatal ventricular arrhythmias, and the presence of dynamic ST-T wave changes, heart failure (ejection fraction < 40), severe anemia, malignancy, sepsis, obesity [body mass index (BMI) > 30 kg/m2], renal failure (glomerular filtration rate < 60 mL/ min/1.73 m2), chronic hematological disease, collagen tissue disease, moderate to severe hepatic failure, severe valvular heart disease, electrolyte disturbance, chronic anti-inflammatory drug use, history of chronic inflammatory disease, and a history of serious infection in the last month.

NSTEMI-ACS patients (n= 276), except for patients with exclusion criteria (n= 32), were divided into two groups as those in need of invasive treatment (n= 217) and medical treatment (n= 59) according to the results of coronary angiography (Figure 1).

BMI was calculated by dividing the weight in kilograms by the square of height in meters. GRACE risk scores for each patient at admission were calculated with the help of a computer program (http://www.outcomes-umassmed.org/grace). We admitted to the Clinicaltrials.gov with the aprotocol number 05.08.2020-2020/15/10 and we are waiting for approval.

Complete blood count parameters obtained from the blood taken during hospitalization using an automatic hematological analyzer (XN 3000; Sysmex Corp., Kobe, Japan) were obtained from the records. Among these parameters, hemoglobin, hematocrit, red cell distribution width (RDW), mean platelet volume (MPV), platelet distribution width (PDW), thrombocyte (P), white blood cells (WBC), immature granulocyte count (IGC), lymphocyte (L) and neutrophil (N) counts was recorded. The N/L ratio (NLR) was determined by dividing the N number by the L number. The P/L ratio (PLR) was determined by dividing the P number by the L number. Systemic Immune-inflammation Index (SII) was calculated using P x NLR formula(7). Routine biochemical tests of each patient, were carried out the next morning after hospitalization, after 12 hours of fasting.

Two interventional cardiologists blinded to the study made angiographic assessments and calculated the Gensini score of each patient(8). TIMI 0-1 flow in the coronary arteries on angiography was defined as complete occlusion.

All echocardiographic assessments were made in line with the recommendations of the guidelines by the American Heart Association(9).

Whether the continuous variables fit the normal distribution was evaluated using the Shapiro-Wilk test and histograms. Continuous variables were presented as mean and standard deviation, and as median (25th percentile-75th percentile) if they were not normally distributed. In the comparison between groups, Student’s t-test was used in accordance with normal distribution, if not, the Mann-Whitney U test was used. Chi-square test or Fisher’s exact test was used to compare categorical variables. The power of the parameters to predict the type of treatment or total occlusion was measured by receiver operating characteristic curves (ROC) calculations. The statistical significance limit was chosen as p< 0.05. All statistical calculations were carried out using SPSS v.23.


Participants were divided into two groups as an invasive treatment and medical treatment. Demographic data, comorbidities and the drugs they used were similar between the groups (Table 1).

The main concern in the study was the comparisons of markers that indicate inflammation between the two groups. There was a significant difference between the two groups in terms of WBC (p< 0.001), SII (p= 0.004), and NLR (p= 0.004) (Table 1). Multivariate analyses and ROC analyzes were performed to evaluate the predictive power of these parameters for invasive treatment. WBC, NLR, and SII were found to predict moderately invasive treatment in patients. It was observed that IGC values, which were found to be significantly higher in multivariate analysis, did not have predictive value in ROC analysis (Figure 2, Table 2, 3).


This study demonstrated that a high SII value and a high NLR may be possible predictors of the need for invasive treatment in patients with NSTEMI-ACS.

Distinguishing NSTEMI-ACS patients who need invasive treatment from others may be important in terms of decreasing cardiovascular mortality, under COVID-19 pandemic conditions. In the literature, there is a lack of literature about the roles of inflammatory hematological markers with predictive properties for cardiovascular mortality in these patients.

One of the main mechanisms that play a role in increasing the tendency of the atheroma plaque to rupture is inflammation(10,11). Leukocytosis, neutrophilia and lymphopenia have been reported to indicate a poor prognosis in ACS(12-14). NLR, a potential inflammation biomarker, is a marker that provides information about the complex inflammatory activity in the vascular bed in NSTEMI-ACS(14). In recent years, it has been reported that the number of immature granulocytes may be used as a prognostic indicator, especially in malignancies(15). It has also been shown to predict high syntax score in patients with ACS(16).

Platelet activation is one of the main mechanisms involved in the etiopathogenesis of ACS. It has been reported that a high platelet count and a decreased lymphocyte count may be associated with a potential thrombotic state and increased inflammation(17). Thrombocytosis, PLR, MPV, and PDW has also been reported to be associated with adverse cardiovascular events(18,19). However, none of these parameters had a significant correlation with the invasive treatment method.

Recently, it has been reported that increased levels of SII, which was developed to evaluate the inflammatory and immune status of patients simultaneously, are associated with poor prognosis in cancer disease(9,20,21). Also, in coronary patients undergoing percutaneous coronary intervention, it was observed that the high SII value predicts major cardiovascular events better than traditional risk factors(7).

This study is probably the first to investigate hematological markers of inflammation in distinguishing patients with NSTEMI-ACS who need invasive therapy. It is vital to differentiate these patients during the COVID-19 pandemic period when invasive treatment strategies cannot be applied to all patients. In this study, it was seen that high WBC, NLR value and SII moderately predicted the need for an invasive treatment strategy in the initial evaluation of NSTEMI-ACS patients.

Its main limitations are that the design of the study is retrospective and the study volume is not large. Especially the relatively smaller number of patients, for whom medical treatment decisions were made, might be a limitation. Another limitation is that the biomarkers commonly used for atherosclerosis were not used in this study.


It is unclear whether the NLR and SII elevation, which may be a predictor of the need for invasive treatment, is a cause or a consequence of the pathophysiological process in patients with NSTEMI-ACS. However, elevated NLR and SII values can help distinguish NSTEMI-ACS patients who need invasive treatment during the COVID-19 pandemic. The results of this study, show the need for large-sized studies to determine the ideal cut-off point of NLR and SII levels in determining the treatment strategy for NSTEMI-ACS.

Cite this article as: Aksu E, Avcı D, Çelik E, Öztürk B, Bozan MB, Göçer K, et al. New predictors in determining the need for invasive treatment in NSTEMI during the COVID-19 pandemic? A retro- spective study. Koşuyolu Heart J 2021;24(1):1-7.

Ethics Committee Approval

The research protocol in line with the Helsinki Declaration was approved by the local ethics committee (Approval Date: 05.08.2020; Protocol No: 2020/15/10).

Author Contributions

Concept/Design - EA, MB; Analysis/Interpretation - EA, DA, MB; Data Collection - EA, EÇ, BÖ; Writing - EA; Critical Revision - EA, DA, KG, AA; Final Approval - EA, AA; Statistical Analysis - DA, MB; Overall Responsibility - EA.

Conflict of Interest

The authors have no conflicts of interest to declare

Financial Disclosure

The authors declared that this study has received no financial support.


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