LABORATORY EVALUATION OF HYPERCOAGULABLE STATES IN PATIENTS WITH CENTRAL RETINAL VEIN OCCLUSION WHO ARE LESS THAN 56 YEARS OF AGE

Purpose: To investigate whether the results of early tests for hypercoagulability are correlated with the development of central retinal vein occlusion risk factors later in life and to evaluate the necessity of these tests in younger patients. Methods: This was a retrospective, observational case series. From January 1995 to December 2014, 55 patients aged below 56 years with central retinal vein occlusion (CRVO) were enrolled in the study. Laboratory evaluations for homocysteine, activated protein C resistance, protein C activity, protein S activity, antithrombin III activity, antiphospholipid antibodies, and anticardiolipin antibodies were obtained at the onset of CRVO. After 24 to 205 months, the presence of risk factors for CRVO such as hypertension, obesity, hyperlipidemia, diabetes mellitus, sleep apnea, and glaucoma was determined. Bilateral correlation and logistic regression were performed to determine the correlations between the results of the initial laboratory tests and the diagnosis of CRVO risk factors. Results: The median follow-up was 168.5 months. Five patients completed at least 24 months of follow-up, 9 patients completed at least 5 years, and 36 patients completed at least 10 years. Five patients had no or less than 24 months' follow-up. Fourteen of 50 patients (28%) had at least one positive test result at the onset of CRVO. At the end of follow-up, 11 patients had been diagnosed with obesity (22%), 29 with hypertension (58%), 21 with hyperlipidemia (42%), 24 with diabetes (8%), 5 with sleep apnea (10%), and 8 with glaucoma (16%). Among 36 patients with a minimum 10 years' follow-up, 30 (83%) developed at least one common risk factor, and none experienced any thromboembolic events. There were no correlations between test results and the diagnosis of any risk factors in patients with a minimum of 2, 5, or 10 years' follow-up (P > 0.05). Conclusion: The results of laboratory tests evaluating hypercoagulability in young patients with CRVO are not correlated with later-developed commonly known risk factors. Many of the common risk factors were present by the end of the study, suggesting that they still remain the core etiology for the disease. The value of the thrombophilic tests is brought into question, as none of the patients demonstrated further clotting or any unusual thrombi with long-term follow-up.