A decision analysis of thrombolytic therapy compared with standard therapy in acute ischaemic stroke

Experts draw different conclusions on whether thrombolysis can be recommended or not for acute ischaemic stroke. A major problem is weighing the improvement in functional ability against the risk of increased mortality. We wanted to examine this uncertainty regarding thrombolysis using a systematic approach and with a strong emphasis on the patient's point of view.

We performed a decision analysis where the base case focused on an average stroke patient. We used published probabilities for different functional outcomes after standard supportive care and after adding tissue plasminogen activator (tPA), and we tried to estimate corresponding long-term survival. We interviewed 158 subjects with the standard gamble method to elicit their preference values (utility) for these outcomes.

When using the baseline data for an average stroke patient, thrombolysis with tPA was the better choice, with 48 extra quality-adjusted living days; tPA was also superior in 117 individual decision analyses, giving from 10 to 173 extra days. However, sensitivity analysis showed that these results were highly susceptible to changes in utility for major disability, probability of early death, and long-term survival after thrombolysis. To increase the gain as well as the margin of safety regarding the treatment choice, thrombolysis should be restricted to patients who assign low utility values < 0.6-0.7 to major poststroke disability (death = 0.0, good health = 1.0).

Evaluated by decision analysis, thrombolysis with tPA is on average superior to standard therapy for the few patients fulfilling the strict medical inclusion criteria. Individual incorporation of the patient's point of view narrows the indication even further.