SAN ANTONIO — The safety of intravenous thrombolytic therapy in patients with unwitnessed strokes surpassed the safety in patients with witnessed strokes when physicians based treatment decisions on the last time patients were seen in their usual state of health, a review of more than 1,500 stroke patients in Ontario shows.
The finding makes sense, because “last time seen normal” is a conservative estimate of stroke onset, Dr. Demetrios J. Sahlas said at the International Stroke Conference.
“Patients with unwitnessed symptom onset were less likely to undergo hemorrhagic transformation following treatment with intravenous TPA [tissue plasminogen activator]” than patients with witnessed symptom onset, reported Dr. Sahlas, professor of stroke management at McMaster University in Hamilton, Ont.
The study results also documented the frequency of unwitnessed stroke among treated patients. Of 1,562 patients who had an out-of-hospital, first-time ischemic stroke in Ontario during July 2003–March 2008 and received intravenous TPA within 5 hours of either their witnessed symptom onset or their last time seen normal, 480 patients (31%) had unwitnessed strokes. The unwitnessed subgroup matched the witnessed patients very closely for demographic and clinical parameters reviewed, including stroke severity, length of stay, mortality, and status at hospital discharge, Dr. Sahlas said at the meeting, sponsored by the American Heart Association.
The 1,562 patients underwent treatment at any one of the 11 designated stroke centers in Ontario. Their average age was 73, and about half were men. During the period reviewed, patients received intravenous TPA if their treatment could be started within 3 hours of either their witnessed symptom onset or their last time seen normal. Patients with unwitnessed strokes had an 8% rate of hemorrhagic transformation following TPA treatment, compared with a 12% rate in patents with a witnessed stroke. In an analysis adjusted for any baseline differences, patients with unwitnessed strokes were 38% less likely to have a cerebral hemorrhage than were those with a witnessed stroke, a statistically significant difference.
Dr. Sahlas said he and his associates had no disclosures.
The finding makes sense, because 'last time seen normal' is a conservative estimate of stroke onset.
Source DR. SAHLAS