Association of Electronic Cigarette Vaping and Cigarette Smoking With Decreased Random Flap Viability in Rats.

IMPORTANCE: Smoking is a known risk to wound healing, but whether electronic cigarettes present the same risk remains unknown. OBJECTIVE: To evaluate the rate of flap necrosis in the e-cigarette vapor-exposed group and the unexposed control and to detect a difference in the rate of flap necrosis between the traditional cigarette smoke-exposed group and the unexposed control. DESIGN, SETTING, AND PARTICIPANTS: From March 10, 2018, to May 4, 2018, a cohort study was conducted on 45 male Sprague-Dawley rats at Boston University School of Medicine. Each rat weighed approximately 100 g at the beginning of the study and was randomized to 1 of 3 groups: negative control (n = 15), experimental (exposed to e-cigarette vapor; n = 15), and positive control (exposed to traditional cigarette smoke; n = 15). Rats in the experimental and positive control groups were exposed to electronic cigarette vapor and traditional cigarette smoke in a smoking chamber for 30 minutes twice a day for 30 consecutive days. Levels of serum cotinine were monitored and maintained between 150 ng/mL and 200 ng/mL. After 30 days, random pattern dorsal skin flaps were raised. MAIN OUTCOMES AND MEASURES: Percentage of flap necrosis for each group. RESULTS: All 45 rats survived the surgical procedure and postoperative recovery, and all rats thrived and gained weight over the course of the study. The highest rate of flap necrosis was found in the positive control cohort, with a mean (SD) of 68.7% (8.6%), followed by the experimental cohort, with a mean (SD) of 65.9% (11.8%); the negative control cohort had the least amount of flap necrosis, with a mean (SD) of 50.8% (9.4%). The percentage of flap necrosis in the negative control rats (95% CI, 46.0-55.6; P < .001) was substantially lower than that for both the positive control rats (95% CI, 64.3-73.0; P < .001) and the experimental rats (95% CI, 59.9-71.8; P < .001). No statistically significant difference in flap necrosis was noted between the rats in the experimental cohort and the rats in the positive control cohort (95% CI, 59.9-71.8 vs 95% CI, 64.3-73.0; P = .46). CONCLUSIONS AND RELEVANCE: Smoking and vaping appear to be equally detrimental to wound healing and to be associated with a statistically significant increase in flap necrosis compared with the unexposed group. The results suggest that vaping should not be seen as a better alternative to cigarette smoking in the context of wound healing. LEVEL OF EVIDENCE: NA.