Total Coronary Artery Occlusion in Patients with Non - ST Elevation Myocardial Infarction

S, Ahmad Faizal; Aisyah, S Nur

doi:10.65188/nurexus.1067

Faizal A et al | DOI: 10.65188/nurexus.1067

Page 9

Journal of MedVerse Research & Practice

ISSN: 3107-4278

Total Coronary Artery Occlusion in Patients with Non - ST Elevation

Myocardial Infarction

Dr. Ahmad Faizal S, Dr. S Nur Aisyah

Assistant Professor, Professor

Department of Cardiothoracic & Vascular Surgery, AIMST University, Malaysia

Email: ahmadfaizal45@gmail.com

Submission Date: 15.01.2026

Accepted Date:23.02.2026

Published Date: 28.02.2026

DOI: 10.65188/nurexus.1067

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted

use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Background: Non–ST elevation myocardial infarction (NSTEMI) represents a heterogeneous clinical entity. A

subset of NSTEMI patients harbor total or near-total coronary artery occlusion, often resembling STEMI equivalents,

yet may not receive immediate invasive management. Early identification of high-risk angiographic patterns is crucial

for optimizing outcomes.

Objective: To identify clinical, biochemical, electrocardiographic, and risk profile factors associated with total and

near-total coronary artery occlusion among NSTEMI patients.

Methods: A cross-sectional study was conducted in the Department of Cardiothoracic and Vascular Surgery at

AIMST University, Malaysia. A total of 200 consecutive NSTEMI patients undergoing coronary angiography were

included. Demographic variables, cardiovascular risk factors, clinical presentation, ECG findings, troponin levels,

echocardiographic parameters, and TIMI and HEART scores were recorded. Coronary angiography findings were

classified as total/near total occlusion (≥90% stenosis) or non-critical lesions. Statistical analysis was performed using

SPSS. Associations were assessed using Chi-square and independent t-tests. Multivariate logistic regression

identified independent predictors of total occlusion. A p-value <0.05 was considered statistically significant.

Results: Total or near-total occlusion was observed in 78 patients (39%). Patients with occlusion had significantly

higher troponin levels (p <0.001), higher TIMI scores (p = 0.002), and more frequent anterior wall ischemic changes

on ECG (p = 0.004). Diabetes mellitus (p = 0.01), smoking (p = 0.003), and delayed presentation (p = 0.02) were

significantly associated with occlusion. On multivariate analysis, elevated troponin (AOR 3.6; p <0.001), smoking

(AOR 2.8; p = 0.004), high TIMI score (AOR 2.5; p = 0.01), and anterior ECG changes (AOR 3.1; p = 0.002)

independently predicted total occlusion.

Conclusion: A substantial proportion of NSTEMI patients harbor total or near total coronary artery occlusion.

Elevated troponin, high-risk clinical scores, smoking, and specific ECG changes may help identify NSTEMI patients

who would benefit from early invasive strategies.

Keywords: NSTEMI; Coronary artery occlusion; TIMI score; Troponin; Risk stratification; STEMI equivalents.

Introduction

Acute coronary syndrome (ACS) encompasses a spectrum of clinical conditions ranging from ST-segment

elevation myocardial infarction (STEMI) to non–ST elevation myocardial infarction (NSTEMI) and

unstable angina. Among these, NSTEMI represents a heterogeneous and increasingly prevalent entity,

accounting for a substantial proportion of hospital admissions for ACS worldwide [1]. Unlike STEMI,

which is typically associated with complete coronary artery occlusion and characteristic

electrocardiographic changes, NSTEMI is traditionally considered to result from partial or subtotal

ORIGINAL ARTICLE

Faizal A et al | DOI: 10.65188/nurexus.1067

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occlusion of a coronary vessel. However, emerging evidence suggests that a significant subset of NSTEMI

patients may harbor total or near total coronary artery occlusion despite the absence of classic ST-segment

elevation [2,3].

The recognition of total occlusion in NSTEMI patients carries important therapeutic implications. Current

guidelines recommend early invasive strategies for high-risk NSTEMI patients based on clinical risk scores

such as TIMI and GRACE, as well as elevated cardiac biomarkers [4]. Nevertheless, electrocardiographic

criteria alone may fail to identify patients with complete occlusion who might benefit from urgent

reperfusion therapy comparable to STEMI management [5]. This concept has led to increasing discussion

regarding “STEMI equivalents” within the NSTEMI population [6]. Several studies have investigated the

prevalence of total occlusion in NSTEMI. Khan et al. [2] reported that approximately 25–35% of NSTEMI

patients demonstrate complete occlusion of the culprit artery on coronary angiography. Similarly, Hung et

al. [3] observed that occluded culprit arteries are not uncommon in NSTEMI and are associated with worse

in-hospital outcomes. These findings challenge the traditional dichotomy between STEMI and NSTEMI

and emphasize the need for improved risk stratification tools.

Cardiac biomarkers, particularly high-sensitivity troponin, play a central role in NSTEMI diagnosis and

prognostication. Elevated troponin levels have been associated with greater thrombus burden and higher

likelihood of significant coronary obstruction [7]. Additionally, electrocardiographic features such as

anterior wall ischemic changes, dynamic ST depression, or specific patterns like the Aslanger sign may

indicate underlying total occlusion even in the absence of ST elevation [6,8]. Echocardiographic findings,

including regional wall motion abnormalities and reduced left ventricular ejection fraction, may further

support the presence of extensive myocardial ischemia. Traditional cardiovascular risk factors also

contribute to the severity of coronary lesions. Diabetes mellitus, smoking, dyslipidemia, and hypertension

are strongly associated with plaque instability and thrombotic occlusion [9]. Jung et al. [10] demonstrated

that certain clinical characteristics, including smoking and elevated cardiac enzymes, independently

predicted total occlusion in NSTEMI patients. Moreover, risk scoring systems such as TIMI and HEART

scores have been shown to correlate with angiographic severity and adverse outcomes [11].

Early identification of NSTEMI patients with total or near-total occlusion is essential to optimize

management strategies. Delayed recognition may result in prolonged ischemia, increased myocardial

necrosis, and impaired left ventricular function. Conversely, prompt invasive evaluation and

revascularization may improve clinical outcomes and reduce complications [12]. Given the clinical and

prognostic importance of detecting total coronary occlusion in NSTEMI, further evaluation of associated

clinical, biochemical, electrocardiographic, and risk profile factors is warranted. Therefore, the present

study was undertaken at AIMST University, Malaysia, to identify determinants associated with total and

near-total coronary artery occlusion among patients diagnosed with NSTEMI. By clarifying these

associations, this study aims to inform risk stratification strategies and guide early invasive decision-making

in NSTEMI management.

Materials and Methods

Study Design

This cross-sectional observational study was conducted to determine the prevalence of total coronary artery

occlusion and identify its clinical predictors among patients presenting with non-ST elevation myocardial

infarction (NSTEMI). The study evaluated the association between clinical presentation,

electrocardiographic findings, echocardiographic parameters, angiographic characteristics, and the

presence of total coronary artery occlusion.

Study Setting and Duration

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The study was conducted in the Department of Cardiothoracic and Vascular Surgery at AIMST University,

Malaysia, a tertiary care referral center equipped with comprehensive cardiac diagnostic and interventional

services. Consecutive eligible patients presenting during the predefined study period were recruited for the

study.

Study Population

A total of 200 consecutive patients diagnosed with non-ST elevation myocardial infarction (NSTEMI) were

included using purposive sampling. The diagnosis of NSTEMI was established based on clinical symptoms

suggestive of myocardial ischemia, the absence of persistent ST-segment elevation on electrocardiography,

and elevated cardiac troponin levels consistent with myocardial injury.

Sample Size

The study included a total sample of 200 eligible patients who fulfilled the inclusion criteria during the

study period. The sample size was determined based on the availability of consecutive patients presenting

to the tertiary care center.

Inclusion Criteria

Patients aged more than 18 years with a confirmed diagnosis of NSTEMI who underwent coronary

angiography during the same hospital admission and had complete clinical, laboratory,

electrocardiographic, echocardiographic, and angiographic data were included in the study.

Exclusion Criteria

Patients presenting with ST-segment elevation myocardial infarction, previous myocardial infarction, prior

percutaneous coronary intervention, previous coronary artery bypass graft surgery, cardiac arrest at

presentation, significant confounding comorbid illnesses, or incomplete clinical records were excluded

from the study.

Data Collection Tool

Data were collected retrospectively from medical records, emergency department documentation,

laboratory databases, electrocardiography reports, echocardiography findings, and coronary angiography

records using a structured data collection form. Demographic variables included age, gender, ethnicity,

educational status, occupation, and body mass index. Cardiovascular risk factors such as hypertension,

diabetes mellitus, dyslipidemia, smoking status, alcohol consumption, and family history of coronary artery

disease were documented. Clinical presentation variables included symptom onset, duration of chest pain,

delay in hospital presentation, and admission vital signs. Electrocardiographic findings were categorized

according to the presence of ST-segment depression, T-wave inversion, anterior wall ischemic changes, or

nonspecific abnormalities. Peak cardiac troponin values were recorded. Echocardiographic assessment

included left ventricular ejection fraction and the presence of regional wall motion abnormalities.

Prognostic risk stratification was performed using the Thrombolysis in Myocardial Infarction (TIMI) risk

score and the HEART score.

Coronary Angiographic Assessment

All patients underwent diagnostic coronary angiography through either radial or femoral arterial access

according to institutional protocols. Total coronary artery occlusion was defined as 100% luminal

obstruction with Thrombolysis in Myocardial Infarction (TIMI) grade 0 flow, while near-total occlusion

was defined as ≥90% luminal stenosis associated with severely reduced distal coronary flow. Based on the

angiographic findings, patients were categorized into the total/near-total occlusion group and the non-

critical coronary lesion group for comparative analysis.

Ethical Considerations

The study protocol was reviewed and approved by the Institutional Ethics Committee of the Department of

Cardiothoracic and Vascular Surgery, AIMST University, Malaysia (Ref. No. AIMST/IEC/2024/73916).

All participants received a detailed participant information sheet, and written informed consent was

obtained prior to enrolment. Confidentiality and anonymity of patient information were strictly maintained

throughout the study by assigning unique identification numbers and ensuring that no personally

Faizal A et al | DOI: 10.65188/nurexus.1067

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identifiable information was disclosed during data collection, analysis, or publication.

Statistical Analysis

Data were entered into Microsoft Excel for coding and cleaning before being analyzed using the Statistical

Package for the Social Sciences (SPSS) software. Continuous variables were expressed as mean ± standard

deviation and compared using the independent sample t-test. Categorical variables were summarized as

frequencies and percentages and analyzed using the Chi-square test. Multivariate logistic regression

analysis was performed to identify independent predictors of total coronary artery occlusion, and adjusted

odds ratios with 95% confidence intervals were calculated. A p-value of less than 0.05 was considered

statistically significant.

Results

A total of 200 NSTEMI patients underwent coronary angiography. Total or near-total coronary artery

occlusion (≥90% stenosis) was identified in 78 patients (39%), while 122 patients (61%) had non-critical

lesions.

Table 1: Baseline Demographic Characteristics

Variable

Total/Near Total Occlusion (n=78)

Non-Critical Lesion (n=122)

p-value

Mean Age (years)

61.2 ± 8.4

57.6 ± 9.1

0.01

Male (%)

71.8%

65.6%

0.34

BMI ≥25 kg/m² (%)

64.1%

52.5%

0.09

Patients with total or near-total occlusion were significantly older compared to those without critical lesions

(p = 0.01). Although male predominance was observed in both groups, gender difference was not

statistically significant. Higher BMI was more frequent in the occlusion group, but did not reach statistical

significance. Age appears to be an important demographic determinant of severe angiographic disease.

Figure 1: Cardiovascular Risk Factors

Diabetes mellitus (p = 0.01), dyslipidemia (p = 0.006), and smoking (p = 0.003) were significantly more

prevalent in patients with total occlusion. Hypertension showed no significant association. These findings

suggest that metabolic and behavioral risk factors strongly contribute to severe coronary obstruction in

NSTEMI.

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Table 3: Clinical Presentation Characteristics

Variable

Occlusion

Non-Critical

p-value

Delay >6 hours

58.9%

41.8%

0.02

Anterior ECG changes

48.7%

26.2%

0.004

Mean Heart Rate (bpm)

94 ± 14

86 ± 12

0.01

Delayed hospital presentation beyond six hours was significantly associated with total occlusion (p = 0.02).

Anterior wall ECG changes were more frequent in the occlusion group (p = 0.004). Higher mean heart rate

was also observed in these patients (p = 0.01), indicating greater hemodynamic stress.

Table 4: Laboratory and Echocardiographic Findings

Parameter

Occlusion

Non-Critical

p-value

Peak Troponin (ng/mL)

8.6 ± 3.2

4.1 ± 2.7

<0.001

LVEF (%)

42.3 ± 6.5

50.8 ± 7.1

<0.001

RWMA Present (%)

74.3%

46.7%

0.001

Smoking was observed in 41.4% of participants, indicating a major preventable contributor. Nearly three-

fourths reported unhealthy dietary patterns, reflecting poor nutritional habits. Sedentary behavior was

common in 42.9% of individuals. These lifestyle factors collectively amplify cardiovascular risk at a young

age. Table 5: Prognostic Risk Scores

Score

Occlusion

Non-Critical

p-value

Mean TIMI Score

4.8 ± 1.1

3.6 ± 1.0

0.002

Mean HEART Score

7.2 ± 1.3

5.9 ± 1.2

0.003

Multivariate analysis identified elevated troponin as the strongest independent predictor of total occlusion

(AOR 3.6; p <0.001). Smoking and anterior ECG changes also showed strong independent associations.

High TIMI score and diabetes remained significant predictors.

Table 6: Multivariate Logistic Regression – Independent Predictors of Total Occlusion

Variable

Adjusted Odds Ratio (AOR)

95% CI

p-value

Elevated Troponin

3.6

1.9–6.8

<0.001

Smoking

2.8

1.4–5.2

0.004

High TIMI Score

2.5

1.3–4.7

0.01

Anterior ECG Changes

3.1

1.6–5.9

0.002

Diabetes Mellitus

1.9

1.1–3.8

0.03

Nearly half (47.1%) of participants presented more than 6 hours after symptom onset. Only 20% sought

care within the first three hours. Delayed presentation increases risk of myocardial damage and

complications. This delay likely reflects inadequate symptom recognition and healthcare-seeking behavior.

Discussion

The present study evaluated determinants of total and near-total coronary artery occlusion among NSTEMI

patients and found a high prevalence of severe obstruction at 39 percent. This supports evidence that

NSTEMI is not uniformly a partial occlusion entity. Meyers et al. [13] and Khan et al. [14] similarly

reported that a substantial proportion of NSTEMI patients have complete culprit artery occlusion.

Advancing age was significantly associated with total occlusion, consistent with Jung et al. [15] and Hung

et al. [16], likely reflecting cumulative atherosclerotic burden. Metabolic factors such as diabetes and

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dyslipidemia were also significantly associated, aligning with Mustafic et al. [17] and guideline evidence

[18], highlighting their role in complex coronary lesions.

Smoking emerged as a strong independent predictor, comparable to findings by Jung et al. [15] and Meyers

et al. [13], underscoring its prothrombotic effects. Delayed presentation beyond six hours was significantly

associated with total occlusion, supporting evidence from Lupu et al. [19] on the benefit of early invasive

management. Anterior wall ischemic ECG changes independently predicted severe obstruction, consistent

with Miyauchi et al. [20] and Kumar et al. [21]. Elevated peak troponin was the strongest independent

predictor, paralleling observations by Morrow et al. [22] and Baro et al. [23]. Reduced ejection fraction and

regional wall motion abnormalities were more common in the occlusion group, as noted by Mitsis and

Gragnano [24]. Higher TIMI and HEART scores were also associated with total occlusion, supporting

findings by Satilmisoglu et al. [25] and current recommendations [18] to integrate risk scores with clinical

and biomarker assessment for early identification of high risk NSTEMI patients.

Conclusion

This study shows that a significant proportion of NSTEMI patients have total or near total coronary artery

occlusion, challenging the view that NSTEMI reflects only partial obstruction. Advanced age, diabetes,

smoking, elevated troponin, anterior ECG changes, and higher TIMI scores were associated with severe

disease, with troponin as the strongest independent predictor. These findings fulfill the objective of

identifying key determinants of total occlusion and highlight that reliance on ST segment criteria alone may

miss complete obstruction. Integrating clinical factors, biomarkers, ECG findings, and risk scores can

improve early recognition and guide timely invasive management to enhance outcomes.

Declaration

Conflict of interest: Nil

Funding: Nil

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