ASA: Smoking May Affect TIA Risk
Reported February 24, 2010
SAN ANTONIO — Smoking was associated with transient ischemic attack (TIA) at a younger age than was seen in those who have quit or have never taken a puff, a retrospective study showed.
At a single center, smokers who sought emergency treatment for a TIA were more than a decade younger, on average, than nonsmokers (age 56.7 versus 72.2 for ex-smokers and 69.1 for never-smokers, P<0.001), according to Nandavar Shobha (Shoba), DNB, DM, a fellow at the University of Calgary in Alberta.
This suggests “a role for smoking-induced thrombus formation in even modest plaques, as significant vascular stenosis was rarely observed in these patients,” she said at a press briefing at the American Stroke Association meeting here.
A similar age effect was not seen among patients with ischemic stroke.
Commenting on the study, Bruce Obviagele, MD, of the University of California Los Angeles, said the reason smoking appears to be related to age at presentation for TIA and not for stroke might have something to do with the clot.
“It’s thought that the kind of TIAs that you see in smokers might be different from the kind of TIAs or stroke in people who don’t smoke or used to smoke,” explained Obviagele, who moderated the press conference at which the results were presented.
The clot itself might be more important than the plaque in smokers, he said.
“That clot is a little bit friable and dissolves very easily,” he said. “So that’s why there might be more TIAs in young people who smoke than in people who have strokes where it’s a persistent event due to occlusion and hard plaque as opposed to that soft clot.”
Shobha and her colleagues decided to look at the effects of smoking status because they were seeing many young patients with TIA whose only risk factor was smoking.
From April 2002 to May 2007, 1,047 patients with acute ischemic stroke (75.4%) or TIA (24.6%) presented to Foothills Medical Center in Calgary within 24 hours of symptom onset.
Overall, 22.3% were smokers, 12.5% had quit at least three months before the event, and 65.2% had never smoked.
All patients had a head CT scan and a CT angiogram of the head and neck. There were no significant differences in disease of the neck or intracranial vessels based on smoking status.
Severity of event did not differ among the three groups.
At three months after the stroke or TIA, the rate of TIA was 6.7% for current smokers, 5.1% for ex-smokers, and 1.7% for those who had never smoked. The differences were not statistically significant.
The rate of stroke at three months was similar in the three groups as well.
Hypertension and dyslipidemia were more frequent in ex-smokers than in current smokers and those who had never smoked (P=0.05 for both).
Smokers were more likely to be male than individuals in the other two groups (70% versus 55%, P=0.003).
Source : MedPage Today