The Syst-Eur trial is a randomised, double-blind, placebo-controlled trial that examines the hypothesis that antihypertensive treatment can prevent or delay cardiovascular complications in elderly patients (> 60 years) with isolated systolic hypertension. On March, 1st 1993 a total of 1395 patients with a sitting systolic blood pressure on placebo averaging 160-219 mmHg and a diastolic blood pressure < 95 mmHg were randomised into this trial. The placebo and active treatment groups were similar at randomisation with respect to age (72 +/- 7 years, mean +/- SD), percentage of women (68%), percentage of patients with cardiovascular complications (30%) and sitting blood pressures (175 +/- 12/85 +/- 6 mmHg). The fall in sitting systolic and diastolic blood pressures from baseline to 2 years was significantly more pronounced (p < 0.001) in the actively treated (-22 +/- 18/-6 +/- 9 mmHg) as compared with the placebo treated Syst-Eur patients (-10 +/- 20/-1 +/- 9 mmHg). Active treatment consists of nitrendipine if necessary associated with a converting-enzyme inhibitor and a thiazide. Whether treatment with these antihypertensive agents results in a clinically meaningful reduction of cardiovascular morbidity and mortality is the subject of investigation in this trial.