Evaluation of regional haemodynamics and alterations of vascu¬lar wall of the lower limbs in hypertensive subjects

This study was designed to analyse the relationship between arterial hypertension and changes in arterial blood flow and vascular wall damage of the lower limbs in hypertensive patients with various degrees of hypertension. Six hundred and fifty-four hypertensive patients (421 males and 233 females) aged 35 to 70 years and 88 healthy subjects (63 males and 25 females) aged 39 to 60 years were studied. Strain-gauge plethysmography of the lower limbs was used to calculate arterial calf blood flow (RF), arterial calf blood flow after post-ischaemic hyperaemia (PF), basal and minimal vascular resistances (BVR and MVR), time to reach peak flow (tPF), time until 50% reduction of peak flow (tT1/2) and total recovery time (tT). In 108 (67 males and 41 females) of the hypertensive patients, a morphological study by echo-Doppler duplex scanning of the popliteal artery was performed to measure medial-intimal thickening and popliteal lumen diameter. Our results indicate that regional haemodynamics of the lower limbs worsened in hypertensives in comparison with control subjects. In addition, the change in peripheral haemodynamics was related to the degree of hypertension. Moreover, medial--intimal thickening was significantly (P < 0.05) higher in severe hypertensives than mild hypertensives. Popliteal lumen diameter was significantly (P < 0.05) lower in severe hypertensives than moderate and mild hypertensives. In all these subjects mean blood pressure was correlated directly (r = 0.31; P < 0.001) with medial-intimal thickening and inversely (r = -0.37; P < 0.001) with popliteal lumen diameter. Multiple regression analysis indicated that mean blood pressure, age and serum cholesterol were independently correlated to medial-intimal thickening. This relationship was not influenced by the diabetic patients and smokers among the groups. Our results indicate that hypertension impairs peripheral flow and encourages the development of medial-intimal thickening.