Effects of intensified blood-pressure reduction on renal function and albumin excretion in primary hypertension: Addition of felodipine or ramipril to long-term treatment with β-blockade

The effect of intensified blood pressure (BP) control with a reduction of the diastolic BP to ≤85 mm Hg on renal function and urinary albumin excretion (UAE) was studied in 28 men with primary hypertension (aged 62 to 72 years) treated for 13 ± 5 years with β-blockade, diuretics, or hydralazine. They were compared with 25 normotensive (NT) men of similar age. At baseline (BL), glomerular filtration rate (GFR), renal plasma flow (RPF) (clearance of inulin and para-aminohippurate), and the UAE were studied. Thereafter, all antihypertensive drugs except β-blockers were withdrawn and either felodipine (5 to 20 mg; n = 13) or ramipril (2.5 to 10 mg; n = 15) was added in a double blind, randomized fashion. Hydrochlorothiazide was added if necessary. The investigations were repeated after 6 weeks and 1 year of double-blind treatment. At BL, the BP and the renal vascular resistance (RVR) were significantly higher and GFR and RPF were significantly lower in both hypertensive groups than in NT. After 1 year, the BP treatment goal was reached by all patients in the felodipine group but only by two-thirds in the ramipril group in spite of addition of diuretics to 60% of the latter group. In the felodipine group, the BP, GFR, and RVR after 1 year no longer differed significantly from normal. The UAE and the fractional albumin clearance increased significantly after 1 yearʹs treatment in the felodipine group but did not change in the ramipril group. The fractional albumin clearance, however, did not differ significantly from normal either at BL or after 1 yearʹs treatment in any of the hypertensive groups. It is therefore possible to reduce BP and improve renal function in primary hypertension to levels not significantly different from normal after treatment with felodipine in combination with β-blockade. Although this regimen increased the low UAE slightly, the fractional albumin clearance changed less and did not differ significantly from normal. The ramipril/β-blocker combination reduced BP less and did not change the slightly reduced renal function or the UAE.