The Effect of Smoking on Sternal Scar Healing

A Prospective Cohort Study

A.E.K. Deliaert, MD, PhD; J.F. Mermans, MD; S.J. Schop, MD, MSc; T.S. Dormaar, MD; E.M. Heerdt, BSc; S.A. Xanthoulea, PhD; J.G. Maessen, MD, PhD; E. van den Kerckhove, PhD; R.R.W.J. van der Hulst


Wounds. 2019;31(8):200-204. 

In This Article

Abstract and Introduction


Introduction: Cardiothoracic surgery with a median sternotomy is an electing factor for the development of a hypertrophic scar. Hypertrophic scars, characterized by an increased vascularity, often result in aesthetic and functional problems. Smoking, due to its negative effects on vascularization, could therefore have an effect on scar healing.

Objective: A prospective cohort study was conducted to evaluate the effect of smoking on scar healing after cardiothoracic surgery with a median sternotomy incision.

Materials and Methods: One hundred patients who underwent cardiac surgery with a median sternotomy were divided into 3 groups: smokers, ex-smokers, and nonsmokers. Erythema values of the scar were measured with a colorimeter on 3 standardized parts of the scar. Scar evaluation was performed at 6 weeks, 3 months, 6 months, and 12 months after surgery.

Results: During 1 year, a total of 90 patients were followed after a median sternotomy; 10 patients were lost to follow-up. There were 23 smokers, 52 ex-smokers, and 15 nonsmokers with an overall mean age of 61.5 ± 8.83 years. No significant difference in redness as a parameter for hypertrophic scarring was observed between the 3 groups. Nevertheless, a trend in favor of the smokers was seen, as they developed less hyperemic scars. The caudal part of the scar showed a significantly higher incidence of hypertrophy compared with the middle and cranial part of the scar (P < .001) at all time points.

Conclusions: It is presumed that a large sample size with younger patients is needed to confirm the results herein. Furthermore, more caudally located skin, especially the subxiphoidal part, is prone to hypertrophic scarring and should, for that reason, be avoided in the incision.


Presternal scarring after cardiothoracic surgery is known for its aberrant scar formation that can lead to hypertrophic or keloid scar formation. These scars are notorious for their functional and aesthetic problems and associated reduced quality of life.[1–3]

Hypertrophic scars develop frequently after full-thickness burn injuries and surgery performed at locations where skin tension is largest.[4,5] The border of a hypertrophic scar remains typically within the confines of the original lesion in contrast to keloids, which are characterized by expansive growth and a genetic predisposition. The thorax is one of the preferential locations for hypertrophic scar formation. These scars are seen in 10% to 57% of Caucasian patients after cardiothoracic surgery.[2,6,7]

The exact etiology for aberrant scar formation remains unclear. One of the predicting factors is an increased vascular density compared with normotrophic scars.[3] Smoking may have a negative effect on the vascularization of a wound due to endothelial dysfunction and is thought to be responsible for a significant increase in postoperative wound complications.[8,9] However, as a side effect, due to its impact on vessels, smoking also may lower the risk of developing hypertrophic scarring.

To examine this hypothesis, a prospective study was conducted in which both redness, as parameter of hypertrophy, and the incidence of scar hypertrophy among smokers, ex-smokers, and nonsmokers after a median sternotomy were evaluated.