The data were collected from a randomized , placebo-controlled trial underway at 7 tertiary-care medical centers to determine whether the combination of an angiotensin I-converting enzyme inhibitor and angiotensin II-receptor blocker was superior to the inhibitor alone , and whether low blood pressure ( < 110/75 mm Hg ) was superior to standard blood pressure ( 120-130/70 -80 mm Hg ) , in delaying renal cystic progression in 558 patients with ADPKD , stages 1 and 2 chronic kidney disease , and hypertension ( age , 15-49 y ) .