Lipoprotein(a) a Risk Factor for Venous Thrombosis and Pulmonary Embolism in Patients Younger Than 50 Years of Age

Introduction: Despite convincing evidence toward causal role of Lipoprotein(a) in occlusive arterial disease, the data is conflicting when it comes to venous thromboembolism (VTE) and pulmonary embolism (PE). Also it is not known if intervention to normalize Lipoprotein(a) will decrease risk of recurrent VTE and PE eliminating the need for life long anticoagulation. To our knowledge this isfirst data set report focusing on evaluating association between Lipoprotein(a) and VTE in patients younger than 50 years old. Methods: Inthis retrospective study, chart review was completed for twenty-six consecutive patients referred to hematology clinic with diagnosis of deep vein thrombosis (DVT) or PE in year 2017-2018 . Four patients older than 50 years old at the time of acute events were excluded. Lipoprotein(a) had only been measured in patients who had negative hypercoagulable work up with normal lipid panel but had obesity . Protein C, S and anti-thrombin were not measured if patients were already on anticoagulation. Serum level of Lipoprotein(a) greater than 75 nmol/L was considered to be elevated. Results: Total of 22 patients (18 females) were included in the data analysis. Nine patients had DVT, 5 patients had PE, and 8 patients had both DVT and PE. Median age was 34 (12-47). Lipoprotein(a) level was not checked on eight patients who had SLE (n=1), surgery (n=1), Factor V Leiden mutation (n=1), protein S deficiency (n=1), anti-phospholipid syndrome (n=2), prothrombin gene mutation (n=1), and one patient who had lost follow up. The median Lipoprotein(a) level was 107 (8-276). Serum Lipoprotein(a) was elevated in 8 out of the 14 screened patients (57%) with the median of 135 (107-276). Out of 8 patients with elevated Lipoprotein(a), only 1 patient had additional clinical risk factors for thrombosis (history of smoking, alcohol abuse, hypertriglyceridemia and elevated LDL). In an attempt to normalize Lipoprotein(a) level, 3 patients were started on niacin but only one tolerated maximum 1000 mg niacin daily which resulted in decrease in level but did not achieve normalization. Conclusion: This data suggests that elevated serum Lipoprotein(a) in females younger than 50 years old is associated with DVT/PE events. Further investigation is required to confirm this finding. At this time it is not known if attempt to normalize Lipoprotein(a) will prevent recurrent PE/DVT and eliminate need for long life anticoagulation in patients with unprovoked VTE who have elevated lipoprotein(a).