NEW ORLEANS — Brief inhalation of dilute diesel exhaust at levels comparable with those encountered curbside along city streets promotes myocardial ischemia in patients with coronary heart disease, said Dr. David E. Newby at the annual meeting of the American College of Cardiology.
He presented the first-ever study in which patients with known CHD were exposed to air pollution in an effort to pinpoint the mechanisms underlying the epidemiologic association between air pollution and increased cardiovascular morbidity and mortality.
“Not everybody believes air pollution is linked to cardiovascular disease, particularly pressure groups backed by the automobile industry,” said Dr. Newby, professor of cardiology at the University of Edinburgh.
He and his coinvestigators in Edinburgh and at Umeå (Sweden) University briefly exposed 20 patients with prior MI to either dilute diesel exhaust at a concentration of 300 mcg/m
Exposure to diesel exhaust caused a threefold increase in the magnitude of exercise-induced ST-segment depression: a mean 49 mcV of ST depression, compared with 17 mcV of ST depression while breathing filtered air during exercise. In addition, blood levels of tissue plasminogen activator—a potent endogenous clot dissolver—declined significantly after patients were exposed to diesel exhaust, providing a second specific mechanism to explain the link between air pollution and cardiovascular events.
In a previous study of healthy volunteers, Dr. Newby and his colleagues showed that brief exposure to real-world levels of diesel exhaust caused impairment of arterial vasodilation. The World Health Organization has estimated that nearly 1 million deaths per year are attributable to inhalation of polluted air.
The British Heart Foundation funded his study.
'Not everybody believes air pollution is linked to cardiovascular disease.' DR. NEWBY
Nearly 1 million people a year die from inhaling polluted air, says the World Health Organization. PhotoDisc, Inc.