Frequency of Thrombophilia-Related Genetic Variations in Patients with Idiopathic Pulmonary Embolism in an Urban Emergency Department (Molecular Diagnostics and Genetics) (Clinical Report‪)‬

Large population-based studies have found that 25% to 50% of patients with confirmed pulmonary embolism (PE)3 have no identifiable risk factors for venous thrombosis (1-4). These idiopathic cases represent a concern for emergency physicians, because patients with idiopathic PE are more difficult to identify prospectively than are patients with traditional risk factors for PE (5-8). Approximately 5%-10% of the general Caucasian population carries either the factor V (FV) [4] Leiden (G1691A) or the factor 11 (F2; prothrombin G20210A) sequence variant, and 20%-25% of unselected patients with venous thrombosis are heterozygous for either variant (9-11). Several investigators have postulated that patients with idiopathic PE are even more likely to carry an unrecognized, inherited thrombophilia that could be detected by laboratory testing (12-14). A patient's pretest probability significantly affects the algorithm to diagnose or exclude PE (15-17). For any patient who self-presents to an emergency department (ED) with signs and symptoms of PE in the absence of overt risk factors for thrombosis, the clinician must con sider the possibility that this patient has an unrecognized thrombophilia, which might increase the patient's pretest probability of PE. At present, no reported study has measured the frequency of thrombophilia-related genetic variants in self-reporting, acutely symptomatic patients ultimately diagnosed with idiopathic PE and compared this frequency with relevant control groups (5,10,12,14).