Does stereotactic thrombolysis with alteplase for intracerebral haemorrhage alter intraventricular haematoma volume? A secondary analysis of the MISTIE-III trial

Background Stereotactic thrombolysis reduces intracerebral haemorrhage (ICH) volume in patients with spontaneous ICH. Whether intrahaematomal alteplase administration is associated with a change in intraventricular haemorrhage volume (deltaIVH) and functional outcomes is unknown.Methods Post hoc secondary analysis of the Minimally Invasive Surgery plus Alteplase for Intracerebral Hemorrhage Evacuation Phase III (MISTIE-III) trial in patients with IVH on the stability CT scan. Exposure was minimally invasive surgery plus alteplase (MIS+alteplase). Primary outcome was deltaIVH defined as IVH volume on end-of-treatment CT minus IVH volume on stability CT scan. Secondary outcomes were favourable functional outcome (modified Rankin Scale 0-3) and mortality at 365 days. We assessed the relationship between MIS+alteplase and deltaIVH in the primary analysis using multivariable linear regression, and between deltaIVH and functional outcomes in secondary analyses using multiple logistic regression.Results Of 499 patients in MISTIE-III, 310 (62.1%) had IVH on stability scans; mean age (SD) was 61.2 +/- 12.3 years. A total of 146 (47.1%) received the MISTIE procedure and 164 (52.9%) standard medical care (SMC) only. The MIS+alteplase group had a greater mean reduction in IVH volume compared with the SMC group (deltaIVH: -2.35 (5.30) mL vs -1.15 (2.96) mL, p=0.02). While IVH volume decreased significantly in both treatment groups, in the primary analysis, MIS+alteplase was associated with greater deltaIVH in multivariable linear regression analysis adjusted for potential confounders (beta -0.80; 95% CI -1.37 to -0.22, p=0.007). Secondary analysis demonstrated no associations between IVH reduction and functional outcomes (adjusted OR (aOR) for poor outcome 1.02; 95% CI 0.96 to 1.08, p=0.61; aOR for mortality 0.99; 95% CI 0.92 to 1.06, p=0.77).Conclusions Alteplase delivered into the ICH in MISTIE-III subjects with IVH was associated with a small reduction in IVH volume. This reduction did not translate into a significant benefit in mortality or functional outcomes at 365 days.Trial registration number NCT01827046.