Correlation of Inflammatory Biomarkers and White Blood Cell Count withCAD Severity and Mortality in Acute Coronary Syndrome Patients

 Introduction

Acute coronary syndrome (ACS) refers to a variety of clinical manifestations caused by acute myocardial ischemia, including unstable angina (UA), non-ST-seg-ment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).

Inflammatory markers like white blood cell (WBC) count and C-reactive protein (CRP) have gained attention for their role in ACS prognosis. Elevated WBC counts are linked to increased risks of recurrent myocardial infarction, heart failure, and short-term mortality in ACS patients. CRP, a marker of systemic inflammation, is also elevated in ACS and is associated with increased cardiovascular morbidity.^1-3

Atherosclerosis and subsequent plaque instability play key roles in ACS pathogenesis, often triggered by inflammation and endothelial damage due to risk factors like hypercholesterolemia, hypertension, diabetes, and smoking. When an inflamed or unstable plaque ruptures, it activates platelets and the coagulation cascade, leading to thrombus formation and restricted myocardial blood flow. Biomarkers, including troponins for myocardial necrosis and CRP for inflammation, are crucial in ACS diagnosis and risk stratification. This study aims to investigate the relationships between WBC count, CRP levels, and 7-day mortality in ACS, offering insights into how these markers might improve early risk assessment and management in clinical settings.^4-5

Materials and Methods

This cross-sectional, observational, correlational study was conducted at Bapuji Hospital and CG General Hospital, Davanagere, from August 2022 to January 2024, with ethical clearance obtained beforehand. All participants provided written informed consent either in English or the local language. A total of 110 patients with chest pain admitted to the Intensive Coronary Care Unit (ICCU) and diagnosed with Acute Coronary Syndrome (ACS) were included, following strict inclusion and exclusion criteria.

ACS patients admitted to ICCU who met the following inclusion criteria were enrolled: age ≥18 years, anginal symptoms in the last 24 hours, ECG changes per ACC/ AHA criteria, elevated cardiac markers, or documented coronary disease. Exclusion criteria included recent infections, systemic inflammation, hepatic or renal dysfunction, haematological diseases, connective tissue disorders, secondary angina, and pre-existing chronic kidney disease.

The study investigated the relationship between baseline white blood cell (WBC) count, C-reactive protein (CRP) levels, and clinical outcomes in ACS patients, categorized into unstable angina (UA), non- ST-segment elevation myocardial infarction (NST-EMI), and ST-segment elevation myocardial infarction (STEMI).

Six mL of venous blood was collected using aseptic techniques upon admission. Blood samples were processed for baseline leukocyte count (2 mL in EDTA tube) and CRP levels (2 mL in serum tube, analyzed via Nephelometry with a detection range of 2-140 mg/L). TROP I levels were assessed using a Rapid Troponin Card Test on the remaining blood sample.

Statistical Analysis: Descriptive and inferential statistical analysis was applied. Continuous data were presented as Mean ± SD, while categorical data were expressed as frequencies and percentages. Statistical significance was set at P < 0.05, with appropriate tests to assess the relationship between WBC count, CRP levels and short-term mortality risk in ACS patients. This methodological framework aimed to enhance understanding of inflammatory markers’ role in ACS prognosis.

Results

The age distribution shows that 53.6% of the patients were between 51-60 years, with a mean age of 53.11 years (SD = 7.19). Males constituted the majority (70%) of the sample, while females accounted for 30%. Regarding patient characteristics, 40% were smokers, 44.5% consumed alcohol, and a significant proportion had comorbidities, including dyslipidemia (46.4%), diabetes (47.3%), and hypertension (55.5%). The ECG findings showed that 50.9% of patients presenting with STEMI, and CRP levels were elevated (≥6 mg/L) in 71% of patients, with a mean CRP level of 21.79 mg/L (SD = 21.95). Troponin I was positive in 78.2% of cases, indicating possible myocardial injury (Table 1).

The Chi-Square and Fisher Exact tests indicated significant differences in gender distribution across ECG findings (P < 0.001), with a higher proportion of females in the unstable angina group (54.2%) and more males in the NSTEMI (63.3%) and STEMI groups (83.9%). Smoking history was also associated with ECG findings (P = 0.014), with prolonged smoking history observed more frequently among STEMI patients.

WBC count significantly varied across ECG findings (P ≤ 0.001), with the highest in STEMI patients (10,558 ± 3,148.6) and the lowest in unstable angina patients (6,792 ± 1,674.36). CRP levels also correlated with ECG findings, showing significantly higher values in patients with NSTEMI and STEMI.

Troponin I showed a significant association with ECG types (P < 0.001), with positive Troponin I predominantly observed in NSTEMI and STEMI cases, while negative Troponin I was more common in unstable angina. At the 7-day follow-up, survival varied by ECG findings: unstable angina had 100% survival, NSTEMI 83.3%, and STEMI 69.6% [Table 1].

Higher WBC counts and CRP levels were strongly linked to increased mortality within 7 days, with deceased patients showing higher mean WBC counts (13,213.64) and CRP levels (46.95 mg/L). Elevated WBC and CRP levels, severe ECG findings, and positive Troponin I emerged as significant predictors of poorer short-term outcomes in ACS patients.

Discussion

This study highlights the significance of baseline WBC count and CRP levels as accessible and effective predictors of short-term mortality in ACS patients. Elevated WBC counts and CRP levels were associated with worse outcomes, consistent with prior findings by Sabatine et al., and Turner et al., who reported higher mortality and complication rates with increased baseline WBC count in ACS patients.^6-7 Elevated WBCs indicate systemic inflammation, which may contribute to plaque instability and thrombus formation, intensi-fying the severity of ACS presentations, especially STEMI. CRP, another inflammatory marker, showed similar associations, suggesting its value in prognostic assessment.^6-8

The findings suggest that WBC and CRP, combined with Troponin I, could enhance risk stratification in resource-limited settings, where advanced scoring tools like TIMI or GRACE may be less accessible. Overall, routine assessment of WBC and CRP can aid in identifying high-risk ACS patients, guiding timely and targeted management strategies to improve outcomes.^7-9

Conclusion

This study demonstrates that elevated baseline leukocyte counts and CRP levels, measured within 12 hours of admission, are strongly associated with short-term mortality in patients with Acute Coronary Syndrome (ACS). Both markers, obtained through routine, accessible methods, correlate significantly (P < 0.001) with adverse outcomes, underscoring their prognostic value. Elevated levels reflect an active inflammatory process that exacerbates ACS severity, supporting the role of inflammation in poor cardiovascular outcomes. Thus, baseline leukocyte counts and CRP levels can serve as valuable early indicators for identifying high-risk ACS patients and guiding timely interventions to improve patient prognosis.

Conflict of Interest

Nil