Unmasking an unusual culprit: Postrenal transplant erythrocytosis as a rare cause of young-onset coronary artery disease

Coronary artery disease (CAD) in young adults is increasingly reported, often in association with nontraditional risk factors. Posttransplant erythrocytosis (PTE) is an uncommon complication following renal transplantation and is associated with increased blood viscosity and a heightened risk of thromboembolic events. A 38-year-old male with long-standing hypertension and chronic kidney disease underwent renal transplantation 4 years earlier. He developed PTE posttransplant, requiring repeated phlebotomies. He presented with acute-onset typical angina of 5–6 h duration. Electrocardiography revealed an extensive anterior wall ST-segment elevation myocardial infarction (MI). Laboratory evaluation showed elevated hemoglobin (17.5 g/dL) and hematocrit (51.4%). Coronary angiography demonstrated a critical thrombotic 90% stenosis in the proximal left anterior descending artery with impaired distal flow. Emergency primary percutaneous coronary intervention was successfully performed, restoring thrombolysis in MI Grade III flow. The patient had an uneventful recovery and was discharged on guideline-directed medical therapy with multidisciplinary follow-up. PTE typically occurs within months to years after kidney transplantation and results from multifactorial mechanisms including persistent erythropoietin activity, activation of the renin–angiotensin–aldosterone system, and other erythropoietic stimulators. Although its incidence is declining, PTE remains an underrecognized cause of arterial thrombosis and premature CAD in young renal transplant recipients. PTE should be considered a potential modifiable cardiovascular risk factor in young patients after renal transplantation. Regular hematological monitoring and timely intervention may help prevent serious thrombotic complications, including MI.