Background: Elevated intracranial pressure (ICP) and inadequate cerebral perfusion pressure (CPP) are mechanisms causing poor outcomes in spontaneous intraventricular hemorrhage (IVH). We characterized intracranial hypertension in severe IVH requiring extraventricular drainage (EVD).
Methods: Prospective analysis of ICP in all 500 patients enrolled in the CLEAR III trial, a multicenter, double-blind, randomized study comparing EVD + intraventricular recombinant tissue plasminogen activator (rtPA) vs. EVD + placebo for treatment of obstructive IVH and intracerebral hemorrhage (ICH) volume <30cc. Maximum and minimum ICP/CPP were recorded every 4 hours until 7 days post randomization (rand), analyzed at pre-defined thresholds and compared by clinical and radiological variables.
Results: of 23,406 ICP readings, maximum ICP ranged from 0-97 mmHg (median, IQR; 11,8); 90.7% (21,223) were ≤20mmHg, 1.8% >30, 0.5% >40, and 0.2% > 50mm Hg. Proportion of threshold events >20mmHg were more frequent with persistent closure of the lower ventricular system after day 3 (p=0.02), and was correlated with initial and end of treatment (72 hours post rand) ICH volumes (p=0.01, p=0.04, respectively). ICP elevation >20mmHg occurred during a required 1 hr EVD closure interval after 566/3712 (15.3%) study agent injections. Early re-opening of the EVD occurred in 3.9%. Shunting for hydrocephalus occurred in 18.6% over 1 year follow-up and was associated with % of high ICP events >20 and 30 mmHg (p=0.01 for both). After adjustment for ICH severity factors and IVH volume, % of ICP readings>20 mmHg was significantly associated with 30 and 180 day mortality (p=0.01; p=0.03 respectively), and borderline with modified Rankin Scale (mRS4-6) (p=0.09; p=0.11 respectively). Proportion of CPP readings <70mmHg was associated with day 30 poor mRS (p=0.02), with a weaker association for day 180 mRS (p=0.07).
Conclusions: Elevated ICP and inadequate CPP are not infrequent during monitoring and EVD drainage in severe IVH and predict higher short and long-term mortality. Early opening of the lower ventricular system may reduce high ICP events. These results permit future correlation of ICP and CPP with treatment rendered (thrombolysis vs placebo), with upcoming unblinding of the trial.