Introduction: CLEAR III trial is a multicenter, double-blind, randomized trial comparing external ventricular drainage (EVD) plus intraventricular recombinant tissue plasminogen activator (rtPA) vs. EVD plus placebo for treatment of IVH in patients with obstructive IVH and intracerebral hemorrhage (ICH) volume <30cc. New hemorrhage along the catheter tract (CTH) associated with EVD placement is known to occur but magnitude and significance of CTH is not well understood. We investigated incidence and severity risk factors for CTH in the CLEAR-III trial.
Methods: Retrospective analysis of 4698 CT scans from EVD placement through EVD removal in all 500 patients enrolled in CLEAR III. CTH was characterized using an ordinal severity scale and quantified using both manual and threshold based segmentation to calculate a volume. EVD location was graded using a modification of the Kakarla scale for each CT scan. Demographic and clinical data were assessed for pre-specified associations.
Results: Incidence of CTH was 44.8% (224/500) which included 318 CTHs (single:160 patients; two:51; three:8; four:8). CTH occurred within first 24 hours of placement in 102 (32%), after 24 hours in 132 (41%), after EVD repositioning/manipulation in 19 (6%), after EVD replacement in 15 (5%), and after EVD removal in 50 (16%). The mean CTH volume was 2.01 ml with a range of 0.1 ml - 57.95 ml. CTH volume was not associated with EVD accuracy, nor number of doses given but increased significantly with the number of catheters placed per patient (p<0.001). Furthermore, Grade 2 or 3 CTH (larger than trace, with or without edema) occurred in 31.8% and were significantly associated with lower platelet count (p=0.047) while grade 2/3 CTH on initial placement were significantly associated with pre-admission antiplatelet agent use (p=0.02).
Conclusion: Our data suggest that EVD tract hemorrhages can occur at any point within the acute treatment period with varying severity. Hematologic factors, especially history of antiplatelet agent use may increase risk of larger potentially symptomatic CTH.