Cigarette smoking increases the development of intimal hyperplasia after vascular injury

Purpose: Our purpose was to determine whether exposure to cigarette smoke increases the development of intimal hyperplasia (IH) after vascular injury. Methods: Sixteen adult male Sprague-Dawley rats underwent standardized balloon catheter injury of the left common carotid artery. For 4 weeks before and 4 weeks after injury, animals in the experimental group (n = 8) were exposed to cigarette smoke with an automated vacuum pump device. Animals in the control group (n = 8) were restrained in the smoking device for an identical amount of time and underwent arterial injury at 4 weeks but were not exposed to cigarette smoke. Carotid arteries were perfusion-fixed in vivo, prepared as histologic cross sections, and stained for elastin. IH was measured by planimetry and is reported both as the absolute area of IH and as the ratio (IH/IEL) of the absolute area of IH to the normalized area enclosed by the internal elastic lamina (expressed as a percent). Results: The absolute area of IH was 2.09 +/- 0.34 for the experimental group compared with 0.94 +/- 0.25 for the control group; mean IH/IEL was 43.7% +/- 7.1% for the experimental group versus 17.7% +/- 4.7% for the control group (p < 0.05, two-tailed unpaired t test). Conclusions: Inhalation of cigarette smoke increases the development of intimal hyperplasia in a rat model of balloon catheter arterial injury.