Two studies recently published in Lancet Neurology indicate that an acute lowering of systolic blood pressure below 140mm Hg is feasible and safe. However, the minimization of blood pressure fluctuations seems to be of prognostic importance.
The evidence on what optimal blood pressure setting looks like in patients with intracerebral hemorrhage (ICH) is patchy. In patients with acute ICH, lowering systolic blood pressure below 140mm Hg can lead to a reduction in blood volume increases. No benefit has been demonstrated so far.
In the INTERACT study (Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial), an acute reduction in systolic blood pressure below 140mm Hg has been shown to be safe and feasible and has reduced the post-operative bleeding rate after ICH. The 'ATACH' study (Antihypertensive Treatment of Acute Cerebral Hemorrhage) also suggested the feasibility and safety of lowering acute blood pressure. The clinical effect of the INTERACT-2 and ATACH-2 studies had not yet been proven. The September issue of Lancet Neurology reported on their results, which we present briefly below.1
The 'INTERACT-2' study in 2,839 patients showed that an intensive lowering of systolic blood pressure (target range < 140mm Hg within 1 h, discontinuation of treatment at < 130mm Hg) within 6 h after ICH improves functional recovery with respect to various secondary outcomes. However, there was no significant difference in the primary endpoint (death or significant disability after 90 days).
The 'ATACH-2' study reviewed a more intensive approach in the first 4.5h (target range 110-139mm Hg within 2h) in 1,000 patients, which did not bring any benefit, but additional renal complications. Meta-analyses showed no overall benefit of early intensive blood pressure reduction compared to the recommended target ranges in the guidelines.
An analysis of the blood pressure variation range in the 'INTERACT-2' patients revealed that the maximum systolic blood pressure in the hyperacute phase (first 24h) and the variability of systolic blood pressure in the acute phase (day 2-7) were the strongest predictors of death or significant disability after 90 days. Smaller studies also provided evidence of benefit by minimizing blood pressure fluctuations around the target range.1
Since both studies excluded patients with hematomas> 60mL and those with high clinical severity (e.g. low GCS - Glasgow Coma Scale), possible associations between the extent of blood pressure lowering and markers for mass effect or increased intracranial pressure (such as hematoma size, obstructive hydrocephalus, large cerebral edema) could have hardly been demonstrated.
However, the benefits or risks of lowering blood pressure and limiting fluctuations are still insufficiently understood, especially for severe hypotension, which could also cause damage. More data is needed for more helpful guidelines. Current results suggest an individualized approach for small and medium-sized ICHs that avoids abrupt, uneven and large drops in systolic blood pressure.
Reference:
1. Ziai, W. C., Gusdon, A. M. & Hanley, D. F. Blood pressure in intracerebral haemorrhage: which variables matter? The Lancet Neurology 18, 810–812 (2019).