Essential Thrombocytosis in Patients <40 Years Old With Acute Coronary Syndromes: A Not So Uncommon Underlying Diagnosis Often Overlooked

Background: In patients under <40 years, traditional cardiovascular (CV)-risk factors are a less likely cause of acute coronary syndromes (ACS) compared to older counterparts. Aims: To estimate the prevalence of essential thrombocytosis (ET), a hematological disorder and less-prevalent risk factor, in young patients presenting with ACS. Methods: We constructed a retrospective database of all patients <40 years (n=271) that had consecutively undergone coronary angiography (CAG) after their first ACS within our hospital within the last ten years (2010-2020) and had known thrombocyte counts (n=241). Patients with thrombocytes >450x10*9/L were screened for this hematological disorder. Results: In our database, we identified 15 subjects with thrombocytosis. One was previously known as ET. Of the remaining 14 patients, five were considered reactive/secondary thrombocytosis, and four were lost to follow-up, four were eventually diagnosed with ET, one remains uncertain. The diagnosis was newly established before the initiation of this study in two patients (average delay: six years). Two patients were identified as a result of this study. Conclusion: With a prevalence of at least 2.1%, ET appears not uncommon in patients <40 years with ACS. Moreover, screening patients with ACS and elevated thrombocytes yielded a novel diagnosis of ET in 27% of patients. The diagnosis was initially missed in all cases. Since the timing of revascularization should be adjusted to thrombocyte count/initiation of ET therapy to prevent thrombotic complications, cardiologists should know, recognize and screen for this pathology in ACS-patients, notably in those with absent traditional CV-risk factors: an ‘ACS-protocol’ aimed at less-prevalent risk factors could support this.