The second (main) phase of an open, randomised, multicentre study to investigate the effectiveness of an intensive blood pressure reduction in acute cerebral haemorrhage trial (INTERACT2).

Rationale: The INTERACT pilot study demonstrated the feasibility of the protocol, safety of early intensive blood pressure lowering and effects on haematoma expansion within 6 h of onset of intracerebral haemorrhage. This article describes the design of the second, main phase, INTERACT2.

Aims: To compare the effects of a management strategy of early intensive blood pressure lowering with a more conservative guideline-based blood pressure management policy in patients with acute intracerebral hemorrhage.

Design: INTERACT2 is a prospective, randomized, open label, assessor-blinded end-point (PROBE). Patients with a systolic blood pressure greater than 150 mmHg and no definite indication for or contraindication to blood pressure-lowering treatment are centrally randomised to either of two treatment groups within 6 h onset of intracerebral haemorrhage. Those allocated to intensive blood pressure lowering will receive primarily intravenous, hypotensive agents to achieve a systolic blood pressure target of <140 mmHg within 1 h of randomisation and to maintain this level for up to 7 days in hospital. The control group will receive blood pressure-lowering treatment to a target systolic blood pressure of <180 mmHg. Both groups are to receive similar acute stroke unit care, therapy and active management. Oral antihypertensive therapy is recommended in patients before hospital discharge with a long-term systolic blood pressure goal of 140 mmHg according to secondary stroke prevention guidelines. A projected 2800 subjects are to be enrolled from approximately 140 centres worldwide to provide 90% power (alpha 0.05) to detect a 14% difference in the risk of death and dependency between the groups, which equates to one or more cases of a poor outcome prevented in every 15 patients treated.

Study Outcomes: The primary outcome is the combined end-point of death and dependency according to the modified Rankin Scale at 90 days. The secondary outcomes are the separate components of the primary end-point in patients treated <4 hours of ICH onset, grades of physical function on the modified Rankin Scale, health-related quality of life on the EuroQoL, recurrent stroke and other vascular events, days of hospitalisation, requirement for permanent residential care and unexpected serious adverse events.