A Norwegian study offers further evidence to support the use of intravenous thrombolysis to treat stroke even in patients with contraindications to the drug.
The analysis found that treatment with tissue plasminogen activator (tPA) improved short-term outcomes and mortality to a similar extent in stroke patients with and without contraindications.
Accordingly, the researchers say that more randomized trials are needed to clarify which patients should and should not be considered for tPA therapy.
Norwegian national guidelines for use of tPA in ischemic stroke patients at the time of the study derived from the strict exclusion criteria of early thrombolytic trials, few of which are evidence-based, explain Christopher Kvistad (University of Bergen) and team.
"As a result, only 2-4% of the ischemic stroke patients receive intravenous thrombolysis, even though 20-30% arrive within 3 hours after symptom onset," they write.
To investigate, the team analyzed outcomes of 265 patients admitted to Haukeland University Hospital with acute cerebral infarction or transient ischemic attack (TIA) between 2006 and 2011.
All patients received tPA within 4.5 hours of symptom onset despite 135 of the patients (50.9%) having contraindications, as judged by national guidelines.
Contraindications included age over 80 years (n=75), systolic blood pressure above 185 mmHg (n=47), diastolic blood pressure above 110 mmHg (n=21), prior stroke or diabetes mellitus (n=6), and prior cerebral hemorrhage (n=3).
Reporting their findings in Acta Neurologica Scandinavica, Kvistad et al say that patients in whom tPA was contraindicated tended to be older and have more severe strokes than those without contraindications.
Despite these differences, patients with contraindications had a similar rate of clinical improvement as those without contraindications, as well as a similar rate of symptomatic intracerebral hemorrhage (SICH).
However, patients with contraindications also showed a trend to less favorable outcomes and higher mortality than those without contraindications.
In logistic regression analysis, stroke severity was the only significant independent predictor of either disability or 30-day mortality; the presence or otherwise of contraindications was not independently associated with outcomes, after adjusting for baseline differences.
Finally, short-term outcomes and mortality were similar between patients with contraindications who received tPA and patients with contraindications who did not receive tPA, Kvistad et al remark.
The researchers conclude: "Our study showed that tPA can be administered safely in ischemic stroke patients with formal contraindications to tPA. The presence of contraindications did not lead to an increase in SICHs.
"Prospective randomized trials are imperative to clarify the need for a re-evaluation of the current contraindications to tPA."
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