Exacerbation of acute platelet thrombus formation in stenosed dog coronary arteries with smoke from a non-tobacco-burning cigarette. The tobacco industry proposes to release a "new" cigarette with a burning charcoal tip, which heats the tobacco as air is drawn through it and into the lungs of the smoker. It is claimed to be safer because the tobacco does not burn. Using our established canine model of coronary artery stenosis with moderate intimal damage, we compared this new cigarette (0.4 mg nicotine) with a regular cigarette by ventilating dogs (n = 10) with room air and then either new or regular smoke (two cigarettes over about 10 minutes). In our dog model, periodic acute platelet thrombus formation followed by embolization produced cyclical flow reductions in coronary blood flow where the rate of flow decline was proportional to the degree of in vivo platelet-vessel wall interaction. The rate of flow decline increased from -4.81 +/- 1.29 ml/min2 to -9.60 +/- 2.29 ml/min2 after ventilation with the new-type smoke (p less than 0.01). Similarly, the rate of flow decline increased from -5.43 +/- 1.28 ml/min2 to -9.28 +/- 2.31 ml/min2 after ventilation with regular cigarette smoke (p less than 0.01). Despite the lack of a clear causal link between cigarette smoking and the acute manifestations of cardiovascular disease, the data presented here indicate that the new cigarette is just as potent as regular cigarettes at increasing in vivo platelet activity and exacerbating acute platelet thrombus formation in the dog. We conclude that the new proposed non-tobacco-burning cigarette has deleterious effects similar to those of conventional cigarettes, and thus does not eliminate smoking as a risk factor in cardiovascular disease in human beings. 