(HealthDay News) – Patients undergoing heart bypass surgery using saphenous veins are more likely to have signs of graft failure if they are smokers, even if they quit smoking more than a year earlier, according to a study published in the January issue of the Annals of Thoracic Surgery.

Yongxin Sun, MD, of Fudan University in Shanghai, and colleagues examined mRNA and protein levels of matrix metalloproteinase (MMP) subtypes MMP-2 and MMP-9 and tissue inhibitors of metalloproteinase (TIMP) 1 and 2 in saphenous vein conduits in 208 patients with various smoking histories who were undergoing coronary artery bypass grafting.

The researchers found that, compared with nonsmokers, expression of MMP2 and MMP9 was significantly higher, and expression of TIMP1 and TIMP2 was significantly lower, in all other patients, whether they were heavy smokers or had quit smoking for any length of time (from three months to long term). Increased expression of MMP2 and MMP9 was associated with poor saphenous vein graft patency.

“With the elevated native MMP2 and MMP9 gene expression in the saphenous vein induced by heavy smoking, more vein graft disease can be found on long-term follow-up,” the authors conclude. “Although recovery after cessation of smoking appears somewhat disappointing, it illustrates exactly the importance of prompt smoking cessation for patients who will receive coronary artery bypass grafting.”

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