Detailed information about the trial design has been published previously.25 (link),26 (link) The study protocol is available with the full text of this article at NEJM.org. Eligible participants were enrolled at seven clinical sites from February 2006 through June 2009. All the participants provided written informed consent. Participants were randomly assigned in a 1:1 ratio to lisinopril plus telmisartan or lisinopril plus placebo. Randomization was performed centrally with the use of permuted blocks. In addition, participants were randomly assigned in a 1:1 ratio to a standard blood-pressure target (120/70 to 130/80 mm Hg) or a low blood-pressure target (95/60 to 110/75 mm Hg), with stratification according to age, sex, race, baseline estimated GFR, and clinical site. The last study visit was in June 2014.
Participants underwent standardized imaging27 (link) in a 1.5-T MRI scanner to determine total kidney volume, left-ventricular-mass index, and renal blood flow at baseline and at 24, 48, and 60 months. Renal vascular resistance was calculated on the basis of blood flow and mean arterial pressure.28 Image analysis was performed,27 (link) and strict quality-control measures were maintained throughout the study.
After randomization, treatment with lisinopril and the masked study medication (telmisartan or placebo) was initiated, and the doses were adjusted in a stepwise fashion to achieve the desired blood-pressure targets (with the use of home blood-pressure measures) while the plasma levels of creatinine and potassium were monitored. Second-, third-, and fourth-line antihypertensive agents were added as needed (Table S1 in the Supplementary Appendix , available at NEJM .org). Central measurements of the serum creati-nine level and local measurements of blood urea nitrogen and electrolytes were obtained at all clinical-site visits, and 24-hour urine collections were obtained for central measurements of albumin, sodium, potassium, creatinine, and aldosterone excretion annually. Adherence to therapy was calculated as the number of drug cards (32 pills per card) given to patients minus the number returned unused during the study period, divided by the number of months of study participation.
Participants underwent standardized imaging27 (link) in a 1.5-T MRI scanner to determine total kidney volume, left-ventricular-mass index, and renal blood flow at baseline and at 24, 48, and 60 months. Renal vascular resistance was calculated on the basis of blood flow and mean arterial pressure.28 Image analysis was performed,27 (link) and strict quality-control measures were maintained throughout the study.
After randomization, treatment with lisinopril and the masked study medication (telmisartan or placebo) was initiated, and the doses were adjusted in a stepwise fashion to achieve the desired blood-pressure targets (with the use of home blood-pressure measures) while the plasma levels of creatinine and potassium were monitored. Second-, third-, and fourth-line antihypertensive agents were added as needed (
