Anterior ST-Segment Elevation Myocardial Infarction Followed by Acute Popliteal Artery Occlusion in a 25-Year-Old Tobacco Smoker with Cannabis Use.

Dalgıç Y.; Karaçimen D.; Duman A.; Kıtlık E.; Solmaz S.; Koç Y.; Önder &. · Turk Kardiyoloji Dernegi arsivi : Turk Kardiyoloji Derneginin yayin organidir · 2026

**Background & Methods** This is a case report of a 25-year-old male tobacco smoker with occasional cannabis use who presented with anterior ST-segment elevation myocardial infarction (STEMI). The patient underwent primary percutaneous coronary intervention of the left anterior descending artery, and subsequently developed acute arterial occlusion in another vascular bed, prompting investigation into underlying thrombophilic and metabolic causes. **Key Findings** - The patient presented with anterior STEMI with severely reduced left ventricular ejection fraction (30%) and apical wall-motion abnormality, followed 12 days later by acute left popliteal artery occlusion (Rutherford IIb), which improved with anticoagulation therapy without requiring revascularization. - Laboratory workup revealed elevated fasting homocysteine (18.4 μmol/L on day 21), low vitamin B12 (121 pg/mL), and low folate (1.9 ng/mL), with subsequent MTHFR C677T and A1298C compound heterozygosity identified on genotyping. - Following vitamin B12 replacement and folic acid supplementation (5 mg/day), homocysteine levels remained mildly elevated at 6 and 18 months (21.6 and 20.7 μmol/L), though folate levels improved to 5.2 and 4.7 ng/mL respectively; the patient remained free of recurrent thrombotic or bleeding events over 18 months on individualized warfarin therapy. **Dosage & Administration** Folic acid 5 mg/day; warfarin dosing individualized based on INR monitoring (specific doses not reported). **Safety & Adverse Effects** Not reported. No bleeding complications or adverse effects from anticoagulation or supplementation were documented during the 18-month follow-up period. **Evidence Quality** This is a single case report with significant limitations. The causal relationship between cannabis use and the thrombotic events cannot be established. The MTHFR polymorphism was considered an accompanying finding rather than a causal thrombophilia. Incomplete follow-up data (renal and thyroid function not reassessed at later measurements) limits comprehensive assessment. The exact mechanism—whether a missed or transient left ventricular apical thrombus—remains speculative. This represents low-level evidence (case report) and serves primarily to highlight an unusual clinical presentation in a young patient with multiple vascular events.

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