RESUMEN
Twenty patients, 15 males and 5 females, with primary varicose veins in 27 lower limbs were included in this study. Their ages ranged between 20 and 45 years. All patients were examined clinically and by the bi-directional Doppler to search for venous valvular incompetence in the communicating and superficial venous systems. At the saphenofemoral junction, clinical examination showed 3 limbs [11.1%] with false negative competent saphenofemoral valves, as proved by Doppler study. At the saphenopopliteal junction, this clinical examination showed only 2 limbs [4.7%] with false negative competent valves. As for the communicating venous valves, clinical examination showed 5 limbs [18.5%] with false negative competent communicating veins, as proved by the bi-directional Doppler to have one or more incompetent communicating veins below the saphenofemoral junction. Also clinical examination showed 4 false negative limbs [14.8%] having competent valves of the saphenous system proved by the bi-directional Doppler to have incompetent valves. The bi-directional Doppler showed a sensitivity of 92.6% in detecting incompetent communicating veins and 96.3% in detecting venous valvular incompetence along the saphenous veins, a result which is superior to the clinical assessment