The effect of smoking cessation on lipid metabolism in patients after coronary artery bypass grafting

Abstract

Aim. The study aimed to comparatively assess lipid metabolism in patients with ischemic heart disease (IHD) before and after coronary artery bypass grafting (CABG) and to evaluate the smoking factor and effects of smoking cessation.

Materials and methods. A total of 122 patients with IHD and indications for CABG were examined (101 men, 21 women; mean age 62.4 ± 0.7 years, range 40–83 years). The patients were divided into two groups: Group I (45 patients <60 years) and Group II (77 patients ≥60 years). Within each group, patients were further divided into subgroups based on smoking status: current smokers (Subgroups IA (n = 28, mean age 55.2 ± 0.9) and IIA (n = 18, mean age 65.0 ± 0.8)) and non-smokers (Subgroups IB (n = 17, mean age 55.2 ± 1.3) and IIB (n = 59, mean age 67.1 ± 0.6)). Lipid metabolism parameters were evaluated at two time points: prior to CABG and six months post-surgery. All patients received statin therapy throughout the study period and those identified as smokers ceased smoking prior to undergoing CABG.

Results. Among smokers (Subgroups IA and IIA), mean levels of proatherogenic lipids were 1.2 to 1.5 times higher, and HDL-C levels were markedly reduced, compared to non-smokers (Subgroups IB and IIB). At 6 months post-CABG, a more pronounced positive change in the lipid profile was observed in Subgroups IA and IIA: LDL-C levels decreased by 47.3 % and 40.7 %, respectively; non-HDL-C by 28.2 % and 24.1 %; and TG by 44.7 % and 29.3 %. In non-smokers, the improvement was less pronounced. At baseline, the proportion of individuals achieving target lipid levels was significantly lower among smokers, regardless of age (p < 0.05): LDL-C <1.4 mmol/L was observed in 46.4 % of Subgroup IA patients compared to 70.6 % in Subgroup IB patients; TG <1.7 mmol/L was achieved by 10.7 % of patients in IA compared to 23.5 % in IB. No individuals in Subgroup IA had target HDL-C or non-HDL-C levels at baseline, whereas these proportions were 29.4 % and 17.7 % in Subgroup IB, respectively. After 6 months, target levels for LDL-C, TG (IA, IIA), and non-HDL-C (IIA) were achieved by 90–100 % of patients (p < 0.05), while the changes in Subgroups IB and IIB were less pronounced.

Conclusions. Among patients with indications for CABG, baseline analysis revealed significantly elevated mean levels of proatherogenic lipids and low HDL-C levels among smokers, as well as the highest proportion of patients failing to achieve target lipid levels, despite prior statin therapy. The most pronounced improvement in lipid metabolism at 6 months was documented among the patients who ceased smoking. These findings suggest that smoking cessation enhances the hypolipidemic effect of statin therapy.