Effect of valsartan addition to amlodipine on ankle oedema and subcutaneous tissue pressure in hypertensive patients

The aim of this study was to assess the effect of valsartan addition to amlodipine on ankle foot volume (AFV) and pretibial subcutaneous tissue pressure (PSTP), two objective measures of ankle oedema. After a 4-week placebo period, 80 grade 1-2 hypertensive patients (diastolic blood pressure (DBP)>90 mm Hg and <110 systolic blood pressure (SBP)>140 mm Hg) were randomized to amlodipine 10 mg or valsartan 160 mg or amlodipine 10 mg plus valsartan 160 mg for 6 weeks according to an open-label, blinded end point, crossover design. At the end of the placebo period and of each treatment period, blood pressure, AFV and PSTP were evaluated. AFV was measured using the principle of water displacement. PSTP was assessed connecting the subcutaneous pretibial interstitial environment with a water manometer. Both amlodipine and valsartan monotherapy significantly reduced SBP (-16.9 and -14.5 mm Hg, respectively, P<0.01 vs baseline), and DBP (-12.9 and -10.2 mm Hg, respectively, P<0.01 vs baseline) but the reduction was greater with the combination (-22.9 mm Hg for SBP, P<0.01 vs monotherapy; -16.8 mm Hg for DBP, P<0.01 vs monotherapy). Amlodipine monotherapy significantly increased both AFV (+23\%, P<0.01 vs baseline) and PSTP (+75.5\%, P<0.001 vs baseline) whereas valsartan monotherapy did not influence them. As compared to amlodipine alone, the combination produced a less marked increase in AFV (+6.8\%, P<0.01 vs amlodipine) and PSTP (+23.2\%, P<0.001 vs amlodipine). Ankle oedema was clinically evident in 24 patients with amlodipine and in six patients with the combination. These results suggest that angiotensin receptor blockers partially counteract the microcirculatory changes responsible for calcium channel blockers induced oedema formation.