Abstract
Background: Acute myocardial infarction (AMI) in adults younger than 45 years is rising globally, and in South Asian populations it is a leading cause of disability-adjusted life-years lost. The pathophysiology is often distinct. Dyslipidemia, and in particular an elevated lipoprotein(a), together with hyperhomocysteinemia, thrombophilia and pro-thrombotic lifestyle factors, makes a greater contribution in older patients. Angiography frequently demonstrates a high thrombus burden in an otherwise minimally diseased coronary tree. In such patients, primary Percutaneous Coronary Intervention (PCI) alone may be complicated by distal embolization, no-reflow and stent thrombosis. Adjunctive strategies such as manual aspiration, glycoprotein IIb/IIIa inhibitors and, in selected cases, Intracoronary (IC) thrombolysis remain relevant.
Case presentation: We report a 38-year-old previously healthy South Indian man who presented with anterior-wall ST-Elevation Myocardial Infarction (STEMI, Killip class I). Emergency coronary angiography demonstrated single-vessel disease with an 80–90% thrombotic lesion extending from the distal left main coronary artery into the proximal Left Anterior Descending artery (LAD), with distal TIMI II flow. Given the massive thrombus burden with preserved distal flow, 10 mg of IC tenecteplase was administered through the guide catheter into the left coronary system. A planned check angiogram on day 5 demonstrated complete recanalization of the LAD with no residual thrombus, and the patient was discharged on guideline-directed medical therapy without stent implantation. Metabolic evaluation identified marked elevation of lipoprotein(a) (151.5 nmol/L; reference 0–75), homocysteine (33.3 μmol/L; reference 5.4–16.2), LDL cholesterol (176 mg/dL) and mildly elevated thyroid-stimulating hormone (4.9 μIU/mL), providing a mechanistic explanation for coronary thrombosis in a young patient without traditional risk factors.
Conclusion: This report contextualizes the case within contemporary evidence on young MI, non-traditional risk factors and IC thrombolysis, and proposes an algorithmic approach for the young STEMI patient presenting with a massive coronary thrombus burden.
Keywords
Young myocardial infarction, ST-elevation myocardial infarction, Intracoronary thrombolysis, Tenecteplase, Coronary thrombus burden, Lipoprotein(a), Hyperhomocysteinemia, Primary percutaneous coronary intervention, Secondary prevention