ABNORMALITIES IN HEMORHEOLOGICAL FACTORS AND LIPOPROTEIN (A) IN RETINAL VASCULAR OCCLUSION - IMPLICATIONS FOR INCREASED VASCULAR RISK

Background The pathogenesis of retinal vascular occlusion (RVO), which includes patients with retinal vein or artery occlusions, may be asso ciated with abnormalities of rheology and coagulation. These abnormali ties have previously been linked with an increased risk of cardiovascu lar disease and stroke. Aim, patients and methods To investigate chang es in haemorheological factors (plasma viscosity, haematocrit, haemogl obin, white cell count (WCC)), plasma fibrinogen (CLAUSS), soluble adh esion molecule P-selectin (associated with platelet activity and ather osclerosis; ELISA), von Willebrand factor (vWf, an index of endothelia l dysfunction; ELISA), fibrin D-dimer (ELISA), lipoprotein(a) (Lp(a), immunoturbidimetric assay) and serum lipids, we conducted a cross-sect ional case-controlled study of 49 patients (37 men; mean age 66.9 year s, SD 12.1 years) with RVO; 34 patients had retinal vein occlusion, wh ilst 15 had retinal artery occlusion. Their results were compared with those in 36 healthy controls (21 men; mean age 63.7 years, SD 14.8 ye ars). Results Patients with retinal vein occlusion and retinal artery occlusion had higher systolic and diastolic blood pressures compared w ith controls (both p < 0.0001). These patients also had significantly elevated levels of plasma viscosity, haematocrit, haemoglobin, plasma fibrinogen, PAI, fibrin D-dimer and serum Lp(a) compared with controls . Apart from a reduction in blood pressure, there were no significant differences in the indices measured in patients with retinal vein occl usion when levels measured during their first and second visits were c ompared. In patients with retinal artery occlusion mean plasma PAI lev els were significantly lower at visit 2 compared with visit 1. Plasma viscosity was significantly correlated with fibrinogen (r = 0.63, p < 0.001), systolic blood pressure (r = 0.33, p = 0.03) and cholesterol ( r = 0.32, p = 0.04), while P-selectin was correlated with Lp(a) levels (r = 0.38, p = 0.03). Conclusion This study suggests that abnormaliti es in haemorheological factors, fibrinogen and Lp(a) are present in pa tients with retinal vein occlusion and retinal artery occlusion. These abnormalities appear to persist even at follow-up examination 4-6 wee ks later. Abnormalities in haemorheological factors, fibrinogen and Lp (a) may have a role in the pathogenesis of retinal vein occlusion and retinal artery occlusion, perhaps acting synergistically with clinical risk factors such as blood pressure. In addition, as haemorheological factors, fibrinogen and Lp(a) are associated with vascular disease, t hese findings in patients with RVO may potentially contribute to an in creased risk of cardiovascular disease and stroke.