Long-term renal and cardiovascular effects of antihypertensive treatment regimens based upon isradipine, perindopril and thiazide

The aim of this study was to describe the renal function (renal hemodynamic s, water and sodium handling) and its relation to cardiovascular structural changes in a population of essential hypertensive patients before and afte r antihypertensive treatment. Glomerular filtration rate and renal plasma f low were measured by a constant infusion technique. The reference substance s used were [I-131]iodohippurate (Hippuran) and [I-125]iothalamate. The lit hium clearance method was used for measuring renal water and sodium handlin g, Microalbuminuria was measured. A subcutaneous gluteal biopsy was taken a nd the media thickness to lumen diameter ratio of small resistance Vessels was determined. Left Ventricular mass index was determined by echocardiogra phy. Thirty-seven patients with newly diagnosed or poorly controlled essent ial hypertension were randomized to treatment with regimens based upon eith er isradipine, perindopril or hydrochlorothiazide-amiloride. Atenolol and h ydralazine were added as secondary and tertiary drugs, respectively, when n eeded for normalization of diastolic blood pressure. Investigations were pe rformed before and after 9 months of normalization of blood pressure. Renal function in untreated hypertensive patients was characterized by increased renal vascular resistance, decreased renal blood flow, normal glomerular f iltration fraction and normal serum creatinine. No association was found be tween peripheral resistance vessel structure in subcutaneous Vessels and re nal hemodynamic parameters. Patients with severe left ventricular hypertrop hy (left ventricular mass >360 g) had lower glomerular filtration fraction, greater renal vascular resistance, lower renal blood how and increased mic roalbuminuria in comparison with patients with less pronounced cardiac chan ges, After 1 year of treatment, which had a profound effect on heart and ve ssel structure, renal hemodynamics were unchanged in patients receiving ant ihypertensive treatment regimens based on the ACE inhibitor perindopril or the Ca-antagonist isradipine, whereas renal plasma flow was reduced, glomer ular filtration rate preserved and filtration fraction significantly increa sed in those treated with a regimen based on diuretics. The serum creatinin e concentration was decreased in the former group, whereas it was unchanged in the latter two. Significantly detrimental effect on uric acid homeostas is was only found in patients treated with a regimen based on diuretics.