COLD PRESSOR TEST AND PLASMA ENDOTHELIN-1 CONCENTRATION IN PRIMARY OPEN-ANGLE AND CAPSULAR GLAUCOMA

Purpose: The authors investigate cutaneous capillary blood flow using the cold presser test and plasma endothelin-l (ET-I) concentration in primary open-angle glaucoma (POAG) and capsular glaucoma (CG), and eva luate the connection between the two factors, which reflect vasoconstr ictive mechanisms with a potential role in the pathogenesis of glaucom a. Methods: The ET-I concentration of venous blood plasma samples from 20 patients with POAG, 22 patients with CG, and 44 healthy volunteers was measured using a radioimmunoassay kit. On a separate occasion, th e right hand was subjected to the cold presser test (hand immersed in 4 degrees C water for 30 seconds, then in 30 degrees C water for 2 min utes), during which cutaneous capillary blood flow of the left middle finger was measured using a Periflux 4001 Master Laser Doppler Flowmet er (Perimed AB, Jarfalla, Sweden). Results: In the CG group, baseline cutaneous capillary blood flow was significantly lower than either tha t of POAG (p = 0.001) or that of the healthy group (p = 0.046). In the CC group, time to maximal cold-induced flow reduction was significant ly longer than in the POAG group (p = 0.028) or in the healthy group ( p = 0.025). Also, recovery time was significantly longer in CG than in the healthy group (p = 0.008) and tended to be longer than in the POA G group. No statistically significant difference between the groups wa s found either in the frequency of increased vasospastic response (col d-induced flow reduction higher than 70% of the baseline value) or in ET-I concentration. No correlation was seen between ET-1 concentration and the findings of the cold presser test. Conclusion: The results su ggest that in CG, which is a systemic disease with vascular abnormalit ies, baseline cutaneous capillary perfusion and its response to cold a nd warmth are altered, without any alteration of plasma ET-1 level. Th e authors found that both plasma ET-I level and the response to the co ld presser test are normal in patients with POAG. These findings sugge st that regulation of cutaneous capillary perfusion and the concentrat ion of plasma ET-I are not related to each other in patients with glau coma.