Effects of losartan titrated to losartan/hydrochlorothiazide and amlodipine on blood pressure and peripheral capillary microcirculation in patients with mild-to-moderate hypertension

Abstract

Objective: To measure the effects of losartan and amlodipine on peripheral capillary microcirculation in hypertension.

Setting: Medical out-patient clinic, Basel, in a university teaching hospital.

Methods: After a 4-week placebo run-in period 20 patients aged 50 +/- 8 (range 36-65) years with mild-to-moderate hypertension were randomly allocated to receive active treatment with losartan 50 mg titrated to losartan 50 mg/hydrochlorothiazide (HCT) 12.5 mg, or amlodipine 5 mg titrated to 10 mg for a 12 week period. Titration was performed if diastolic blood pressure (BP) was > or=90 mm Hg after 6 weeks of treatment. BP measurements as well as video capillary microscopy of the finger nailfold at the end of the placebo period and after 12 weeks of active treatment were compared. Capillary blood cell velocity was measured at rest and immediately, 1 min and 2 min after local finger cooling.

Results: After 3 months of treatment with amlodipine (n = 10) and losartan titrated to losartan-HCT (n = 10) sitting BP decreased significantly from 160 +/- 7/103 +/- 4 mm Hg and 147 +/- 7/98 +/- 6 mm Hg to 131 +/- 10/86 +/- 7 mm Hg and 134 +/- 17/89 +/- 9 mm Hg, respectively (P < 0.01). After local finger cooling the area under the curve (AUC) of capillary blood cell velocities was 1.13 +/- 0.58 mm (median +/- s.d.) at baseline and increased to 1.94 +/- 1.15 (P < 0.05) in losartan/losartan-HCT treated patients. In amlodipine treated patients the increase in AUC of capillary blood cell velocity did not reach the level of statistical significance (1.59 +/- 1.36 to 2.14 +/- 1.05 mm).

Conclusion: This small trial shows that the area under the curve of capillary blood cell velocity increases in hypertensive patients treated with both losartan/losartan-HCT and amlodipine compared with baseline values.