The whole thing is driving Dr. Lasner "nuts" because many of his friends are heavy smokers. Todd Lasner, a young neurosurgical resident, hopes those friends will stop smoking once they hear about the findings unearthed by a research team at the University of Pennsylvania Medical Center. There, Lasner and his colleagues demonstrated, for the first time, a scientific link between smoking cigarettes and cerebral blood-vessel damage. In a report to be published in the Journal of Neurosurgery [September 1997], the scientists have shown that smoking increases one's risk of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH).
"This study is another piece of evidence to support how bad cigarette smoking is on the integrity of blood vessels," says Eugene Flamm, MD, Penn's Chairman of the Department of Neurosurgery and principal investigator of the study, "and it confirms the general impression of a lot of neurosurgeons that patients who smoke have a much more difficult time recovering from a brain hemorrhage than their non-smoking counterparts."
Vasospasm is a violent constriction of arterial walls that interferes with proper blood flow. Following surgery to correct a brain aneurysm, vasospasm occurs when blood spews into the subarachnoid region of the brain. (Such a hemorrhage is an expected complication from aneurysm surgery.) Depending on the intensity and duration of the vasospasm, patients may develop stroke-like symptoms -- including impaired speech, facial movement, and bodily sensations -- that result from the insufficient transport of oxygen to affected brain cells. Indeed, vasospasm is the major cause of delayed death in patients with disrupted aneurysms, and occurs in approximately one-third of all patients who get aneurysms.
For the study, Lasner examined the demographic features and clinical parameters (including smoking, high blood pressure, incidence of heart disease and diabetes) of 70 patients with aneurysmal SAH. They calculated that smokers have nearly five times the chance of developing vasospasm than non-smokers -- all other factors being equal.
The biochemical basis for the increased risk found in the study is unclear. It has been theorized, however, that smoking causes a rise in the serum level of endothelin -- a powerful vasoconstrictor that may mediate vasospasm. Cigarette smoking also seems to induce the impairment of blood vessels by increasing the adherence of plaque-causing molecules onto arterial walls.
"While the exact nature of smoking-induced biochemical deterioration remains cloudy, one message from this study is quite clear -- smoking is hazardous to your health!" says Dr. Lasner. "And, even if I can't convince my friends to quit, I hope the results of our study may prevent others from starting to smoke or convince them to stop."