Abstract W P1: Efficacy of IV TPA in Endovascular Trials: A Pooled Analysis
Background: IV TPA is the comparator for many studies of endovascular therapies (EVT) in acute ischemic stroke. We analyzed the efficacy of IV TPA reported in recent large EVTs and compared it to earlier studies. Our hypothesis was that the perceived failure of various therapies in recent EVT trials was due to the unanticipated efficacy of IV TPA alone and not the failure of EVT. This may have adversely affected the design and power assumptions of recent trials.
Methods: We analyzed baseline and outcome data from recent large trials of IV TPA vs placebo and IV TPA alone vs various EVTs with or without IV TPA. Studies included were ECASS I-III, ATLANTIS, NINDS, SITS-MOST, EPITHET, IMS3, and SYNTHESIS. Onset to treatment times, age, and baseline NIHSS scores were examined. The primary outcome was a modified Rankin of 0-2 at 3 months for the IV TPA only patients. When possible we analyzed patients treated 4.5 to 6 hr after symptom onset to mirror the treatment delays seen in EVT.
Results: Across all studies there were 8736 IV TPA only treated patients. The median age was consistent across all trials (67-68 years), as was the mean NIHSS score (11-13 for all, except for 16 in IMS3). Good outcomes were achieved in 40% to 46% of IV TPA only treated patients in the EVT trials compared to 49% for those treated in IV TPA vs placebo trials and 55% treated in open-label IV TPA registries. Limiting the analysis to patients treated 4.5 to 6 hr after stroke onset showed 49% of patients had a good outcome with IV TPA alone vs placebo. One EVT trial under-estimated the efficacy of the IV TPA only arm, with an assumed good outcome rate of only 40% (vs 46% in the actual trial).
Conclusions: Among patients enrolled in EVT trials, IV TPA alone performs quite well, with up to 46% of patients having a good outcome. Any EVTs will have to demonstrate robust efficacy to show a superior clinical benefit when compared to IV TPA alone.
Author Disclosures: M.J. Alberts: Speakers' Bureau; Modest; Genentech. Honoraria; Modest; Genentech. B.J. Connors: None. R. Novakovic: None. C. Olivera: None.
- © 2014 by American Heart Association, Inc.