RESUMEN
STUDY OBJECTIVE: To test venous endothelial function in long-term climateric therapy with tibolone. DESIGN: Measurement of dorsal hand-vein diameter by venous occlusion plethysmography during infusion of norepinephrine (NE), bradykinin (BK), NG-monomethyl L-arginine (L-NMMA) and sodium nitroprusside (SNP). SETTING: Plethysmography and Menopause Units. University Hospital Valdecilla. Santander. Spain. PATIENTS: Eleven postmenopausal women having continuous treatment with oral tibolone (2.5 mg/day) for 6 months. INTERVENTIONS: Three plethysmography studies were made: at baseline, and at three and six months of treatment. MAIN OUTCOME MEASURES: Dorsal hand-vein diameter measured by venous occlusion plethysmography during infusion of NE, BK, L-NMMA and SNP. RESULTS: (a) Baseline study: maximum dilation with BK was 54.2+/-10.2%. (b) Three-month study: BK dilation of 71.5+/-11.9%, with a significant increase of 17.3% (P=0.019) compared with baseline. (c) Six-month study: BK dilation of 77.5+/-11.9%, with a significant increase 23.3% (P=0.002) compared with baseline. Maximal vasodilation was reached with SNP in the three studies and L-NMMA infusion has a similar vasoconstrictor response in the three studies. CONCLUSIONS: Long-term climateric therapy with tibolone improves vein endothelium-dependent vasodilation suggesting a positive impact of this drug on endothelial function.