Smoking Hurts Bypass Odds

Smoking habits can alter chances of a successful bypass graft even a year after quitting

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) There are a lot of reasons to quit smoking. Improved outcomes in bypass surgery is one of them. Quit now and be healthier sooner and later.

A recent study looked at a group of patients in need of coronary artery bypass grafting to improve blood flow through the heart. The group was split into groups defined by smoking habits. Nonsmokers and long-term quitters had much better rates of success than heavy smokers and recent quitters.

"Talk to your doctor about a plan to stop smoking."

Sun Yongxin, MD, from the Department of Cardiac Surgery at Zhongshan Hospital at Fudan University in Shanghai, China, led a team to investigate the effects of smoking on heart surgery, even after quitting smoking.

For the study, 208 coronary artery bypass grafting (CABG) surgery patients were split into six groups:

  • Nonsmokers (36)
  • Heavy smokers (45)
  • 3-month quitters (33)
  • 6-month quitters (27)
  • 12-month quitters (38)
  • Long-term quitters (29)

In CABG, part of the saphenous vein from the leg is used to repair the coronary artery to recreate open and healthy vascular flow.

In order for a CABG to be successful, the vein needs to be healthy and fully functional for the graft to properly take. The goal is for CABG to be successful for the lifetime of the patient.

In the saphenous vein there are specific enzymes, a matrix of metalloproteinase enzymes to be exact. Heavy smoking can increase these levels and throw off the enzyme balance in the vein, making it less viable for successful grafting.

Researchers found smoking was related to higher levels of metalloproteinase, which was linked to vein graft disease in post-surgical follow-up.

Follow-ups were done with multi-detector spiral computed tomography (MSCT) coronary angiographic assessment at 1 month, 1 year and 2 years after surgery.

Enzymes were more than five to nine times greater in heavy smokers compared to nonsmokers. Levels were still nearly double for 12-month quitters compared to nonsmokers. Long-term quitters had slight elevations of enzymes, but less than 1.5 times that of nonsmokers.

Authors said, “[A] noticeable recovery needs at least 6 months (of the enzymes from quitting smoking), and the recovery cannot return to normal levels…[and] can be found in the data from long-term follow-up.”

Post-operative complications were greater in patients who continued to smoke, including heart attack and the need for a re-operation of the CABG.

Authors stressed the need to encourage smoking cessation for quality of health.

This study was published in January in The Annals of Thoracic Surgery.

Research was supported by a grant from the Shanghai Medical Development Research Fund.

No conflicts of interest were reported.

Reviewed by: 
Review Date: 
January 3, 2013
Last Updated:
January 3, 2013