European Journal of Cardiovascular Medicine

Acute Coronary Syndrome (ACS) represents a spectrum of ischemic heart diseases, including Unstable Angina (UA), Non-ST Elevation Myocardial Infarction (NSTEMI), and ST-Elevation Myocardial Infarction (STEMI), all of which are caused by the sudden reduction of blood supply to the myocardium. Historically, ACS has been viewed as a disease of the elderly, associated with advanced age and long-standing comorbidities. However, recent epidemiological trends indicate a significant demographic shift, with a rising prevalence of ACS in young adults, defined as those aged 40 years or younger.

The pathophysiology of ACS in young adults often differs from that in older populations. While plaque rupture remains a primary mechanism, young patients may also present with non-atherosclerotic causes such as spontaneous coronary artery dissection (SCAD) or coronary vasospasm induced by substance abuse. Furthermore, the risk factor profile in young adults is distinct. Rapid urbanization and lifestyle changes have led to an increase in smoking, sedentary behaviour, obesity, and metabolic syndrome among the youth. Smoking, in particular, accelerates atherosclerosis and promotes a pro-thrombotic state, making it a critical determinant of premature coronary artery disease (CAD).

Clinical diagnosis in this age group can be challenging. Young patients often present with atypical symptoms, such as fatigue or epigastric pain, rather than classic angina, leading to potential delays in medical contact and treatment. Despite generally having fewer angiographic comorbidities than older patients, young ACS survivors face a lifetime of cardiovascular risk and potential recurrence.

This study was undertaken to examine the clinical profile, risk factors, and angiographic patterns of young ACS patients in a tertiary care setting in North India. By identifying specific determinants, such as lipid abnormalities and metabolic risks, this research aims to inform the development of targeted preventive strategies for this vulnerable population.

Study Design and Setting This was a hospital-based observational study conducted at the Department of General Medicine and Cardiology, Aakash Healthcare Super Speciality Hospital, New Delhi. The study spanned a period of 1 year and 8 months, from February 2024 to October 2025.

Study Population: The study enrolled 61 young adults presenting with Acute Coronary Syndrome.

1. Sample Size: Calculated based on the prevalence of ACS in the <40 age group (approx. 8%) with a 95% confidence interval, resulting in a sample size of 61 patients.
2. Inclusion Criteria: Patients aged less than 40 years diagnosed with Acute Coronary Syndrome.
3. Exclusion Criteria: Patients aged ≥40 years, those refusing consent, or patients with known cardiomyopathy, myocarditis, previous cardiac surgery, rhabdomyolysis, acute pulmonary embolism, or stroke.

Data Collection: Detailed history taking and clinical examinations were performed for all subjects. The collected data included demographic details, presenting symptoms, and traditional risk factors (smoking, hypertension, diabetes, dyslipidemia, and obesity). Investigations included:

1. Biochemical analysis: Lipid profile, HbA1c, renal function tests, and cardiac biomarkers (Troponin I, CK-MB).
2. Cardiac Imaging: 12-lead Electrocardiogram (ECG) and 2D-Echocardiography to assess wall motion abnormalities and ventricular function.

Statistical Analysis Data were entered into a Microsoft Excel spreadsheet and analyzed using SPSS software. Quantitative data were expressed as Mean ± Standard Deviation (SD), while qualitative data were presented as percentages and proportions. The Student’s t-test was used for mean differences, and the Chi-square test was used for categorical associations. A p-value of <0.05 was considered statistically significant.

Demographic Profile The study population comprised 61 patients with a mean age of 35.00 ± 4.36 years. The majority of patients (55.74%) were in the age group of 36–40 years, followed by 34.43% in the 31–35 years group. There was a significant male predominance, with 50 males (81.97%) and 11 females (18.03%).

Clinical Presentation The most common presenting symptom was typical chest pain, reported by 52 patients (85.25%). Atypical symptoms were observed in 14.75% of cases and included dyspnea (4.45%), epigastric pain (3.33%), sweating (1.11%), and sudden collapse (1.11%).

Risk Factor Analysis Analysis of cardiovascular risk factors revealed a high burden of modifiable risks:

1. Smoking: The most prevalent risk factor, present in 55.74% of patients.
2. Dyslipidemia: Observed in 52.46% of patients.
3. Metabolic Disorders: Obesity was present in 37.70% and Diabetes Mellitus in 36.07% of the cohort.
4. Hypertension: Present in 26.23% of patients. Notably, 68.85% of patients had multiple (more than one) coexisting risk factors, while only 8.2% had no identifiable risk factors.

Laboratory and Lipid Profile Among patients with dyslipidemia (n=32), the lipid abnormalities were severe:

1. Elevated LDL (>100 mg/dL): Found in 81.25% of dyslipidemic patients.
2. Low HDL (<40 mg/dL): Observed in 75.00%.
3. Hypertriglyceridemia (>150 mg/dL): Seen in 62.50%. Cardiac biomarkers were significantly elevated, with Troponin I and CK-MB positive in 91.8% of the total study population, confirming significant myocardial injury.

ACS Type and ECG Findings

• Predominant Type: STEMI was diagnosed in 49 patients (80.33%), while NSTEMI occurred in 12 patients (19.67%).
• Infarct Location: Among STEMI patients, Anterior Wall MI (AWMI) was the most frequent presentation (59.18%), followed by Inferior Wall MI (30.61%) and Lateral Wall MI (10.21%).

Echocardiographic Findings: Structural and functional assessment revealed that 60.66% of patients had Left Ventricular (LV) systolic dysfunction. Regional Wall Motion Abnormalities (RWMA) were detected in a vast majority (88.52%) of patients, reflecting the high prevalence of transmural infarction in this young cohort.

The rising incidence of Acute Coronary Syndrome in young adults is a pressing public health concern, particularly in developing nations like India. Our study characterized the clinical and risk profile of 61 young ACS patients, revealing distinct patterns compared to older populations.

Epidemiology and Gender Disparity: Our findings align with global trends showing a male dominance in premature ACS. We observed a male-to-female ratio of roughly 4.5:1 (81.97% males). This is consistent with studies by Pruthvi C et al. and Tsai et al., who reported male percentages of 96.2% and 89.8%, respectively. The relative protection of premenopausal women via estrogen, combined with higher rates of smoking and metabolic stress in young men, likely contributes to this disparity.

Risk Factor Burden

Smoking emerged as the single most critical modifiable risk factor (55.74%), corroborating findings from the INTERHEART study and regional data by Kattimani et al., where smoking was present in 64% of young ACS cases. The pro-thrombotic and endothelial-damaging effects of tobacco are particularly potent in young arteries, often precipitating acute events even in the absence of severe stenosis. Dyslipidemia was the second most common factor (52.46%), characterized notably by high LDL and low HDL levels. This "atherogenic triad" of high triglycerides, high LDL, and low HDL is typical of the metabolic syndrome phenotype prevalent in South Asians.

Clinical and Angiographic Patterns The predominance of STEMI (80.33%) in our study mirrors findings from the CREATE registry and other Indian studies. Young patients typically present with STEMI due to abrupt thrombotic occlusion of a vessel that has not yet developed collateral circulation, unlike older patients with chronic ischemia. The high incidence of Anterior Wall MI (59.18%) indicates a predilection for the Left Anterior Descending (LAD) artery. This is significant as LAD involvement is associated with larger infarct size and greater impact on LV function, as evidenced by the 60.66% rate of systolic dysfunction in our cohort. Our results suggest that while young patients may have fewer comorbidities than the elderly, their disease is aggressive, often involving single-vessel disease with heavy thrombotic burden.

Acute Coronary Syndrome in young adults (<40 years) is no longer a rarity and is predominantly driven by modifiable lifestyle factors, specifically smoking and dyslipidemia. Clinicians must maintain a high index of suspicion for ACS in young patients presenting with chest pain, as they frequently present with severe ST-elevation myocardial infarction (STEMI) and significant ventricular dysfunction. Aggressive primary prevention targeting smoking cessation and lipid management is imperative.

1. Thygesen K, Alpert JS, Jaffe AS, et al. Fourth Universal Definition of Myocardial Infarction (2018). J Am Coll Cardiol. 2018; 72:2231.
2. Vasan RS, Beiser A, Seshadri S, et al. Trends in risk factors for cardiovascular disease in young adults: The Framingham Heart Study. JAMA. 2014;311(1):12-19.
3. Virani SS, Alonso A, Benjamin EJ, et al. Global burden of cardiovascular diseases and risk factors, 1990–2019. JAMA. 2020;324(2):129-130.
4. Soni A, Hwang S, Pandit S, et al. Acute coronary syndrome in young adults: The impact of emerging cardiovascular risk factors. J Clin Lipidol. 2018;12(1):91-97.
5. Chrysafides SL, Hamilton R, Marshall M, et al. Cocaine-associated myocardial infarction in young adults. J Clin Cardiol. 2012;35(3):204-210.
6. Saw J, Aymong E, Mancuso L, et al. Spontaneous coronary artery dissection: Updates on diagnosis and management. Eur Heart J. 2016;37(21):1786-1794.
7. Esteban MR, Montero SM, Sánchez JJ, et al. Acute coronary syndrome in the young: clinical characteristics, risk factors and prognosis. Open Cardiovasc Med J. 2014; 8:61-7.
8. Deora S, Kumar T, Ramalingam R, Nanjappa Manjunath C. Demographic and angiographic profile in premature cases of acute coronary syndrome: analysis of 820 young patients from South India. Cardiovasc Diagn Ther. 2016;6(3):193-198.
9. Deshmukh PP, Singh MM, Deshpande MA, Rajput AS. Clinical and angiographic profile of very young adults presenting with first acute myocardial infarction: Data from a tertiary care center in Central India. Indian Heart J. 2019;71(5):418-421.
10. Revaiah PC, Vemuri KS, Vijayvergiya R, et al. Epidemiological and clinical profile, management, and outcomes of young patients (≤40 years) with acute coronary syndrome: A single tertiary care center study. Indian Heart J. 2021;73(3):295-300.
11. Pandey C, Singh R, Talokar PKV, et al. Acute Coronary Syndrome in Young (≤45 Years) Patients: An Observational Study. Journal of the Practice of Cardiovascular Sciences. 2023;9(2):121-126.
12. Kassam N, Ngunga M, Varwani M, et al. Acute coronary syndrome patterns in the Young: risk factor profile and in-hospital outcomes in a tertiary referral hospital in Kenya. BMC Cardiovasc Disord. 2024;24:192.