In 2013, one of my then very new colleagues in Berlin published a very interesting paper with the title “Smoking-thrombolysis paradox: recanalization and reperfusion rates after intravenous tissue plasminogen activator in smokers with ischemic stroke”. When you translate this to something less technical, you will conclude that it appears that stroke patients who smoke seem to react better to acute treatment. The drug that they get administered seems to perform better with opening up the blood vessels in the brain so that the oxygen rich blood for can flow again. It sounds weird, even to us at the time, but there is -albeit unlikely – biological scenario that could actually explain this finding.
Irrespective of biology , this first finding was too preliminary to draw strong conclusions as it is based on imaging outcomes only. It didn’t say anything on whether the patients who were active smokers ended up having fewer symptoms. So that’s where this project came is. Using data from the Dutch PSI study, we were able to study the effect of the treatment and whether that effect was actually different in patients who smoked.
The short answer is no – we didn’t find evidence that patients who were active smokers would actually have more benefit from thrombolysis. If we had found this effect, the RR should have been much extremer in the +/+ category than the effect in the +/- category. In fact, all that we saw showed that there was no real difference. But there are some serious limitations to our study, with the main one being that the patients included in this dataset might not have been the best subset of stroke patient to study this phenomenon. So, even though we didn’t see evidence of the phenomenon, we can’t rule it out and conclude, as so often, “that future research is needed”. Before you ask, yes, we indeed did that future research ourselves. The paper is currently under review, but I can already tell you that the conclusion is not going to change a lot. But that paper is still under review (hint: nothing changes)