Smoking is the strongest modifiable risk factor for mortality post coronary revascularisation

The prevalence of coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) is increasing in the general population due to improved prognosis and access to procedures. However, the risk of cardiovascular events and death remains elevated post coronary revascularisation despite the availability of novel medical therapies. In the current study, we aimed to determine the association of the conventional cardiac risk factors to mortality in invasively treated coronary artery disease (CAD) patients in a random sample of Finnish individuals drawn from the general population. The FINRISK studies are carried out every 5 years by the Finnish National Institute for Health and Welfare. The studies are based on stratified random samples of the population aged 25–74 years from specific geographical areas of Finland. Of the 23,803 participants examined in the FINRISK 2002, 2007 and 2012 studies, we identified 383 individuals who had undergone PCI or CABG, and had data available for post revascularisation CAD risk factors and additional variables important for secondary prevention (age, sex, body mass index (BMI), smoking, diabetes, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, systolic blood pressure (SBP), leisure-time physical activity, chronic obstructive pulmonary disease, peripheral artery disease and heart failure). The main outcome was all-cause mortality registered in the nationwide causes of death register before 31 December 2017. Baseline characteristics between cohorts were compared using analysis of variance. We used Cox proportional hazards models and population attributable fractions to determine the relationship between CAD risk factors and death. All risk factors and the cohort year were simultaneously included in the model as dependent variables. A P value less than 0.05 was considered statistically significant. The mean age of invasively treated CAD patients increased from 62.4 years in 2002 to 66.0 years in 2012 (P< 0.001; Table 1). The proportion of CABG patients decreased markedly during the study period from 70% in 2002 to 45% in 2012 (P< 0.001). In addition, the mean LDL-cholesterol and the proportion of heart failure patients decreased from 2.8 (0.8) to 2.2 (0.8) mmol/l (P< 0.001) and from 22.6% to 10.1% (P1⁄4 0.024), respectively. The proportion of patients with diabetes increased from 15.0% to 28.7% from 2002 to 2012 (P1⁄4 0.03). Other risk factors did not significantly change from 2002 to 2012 (Table 1). Ninety-one (23.8%) individuals died over a median follow-up of 10.8 years. Expectedly, age was positively associated with increasing the risk of death after PCI or CABG (hazard ratio (HR) 1.08 per 1 SD increase, 95% confidence interval (CI) 1.04–1.12, P< 0.001). Peripheral artery disease (HR 1.90, 95% CI 1.02– 3.56) and heart failure (HR 1.66, 95% CI 1.00–2.75) both slightly increased the risk of death (Table 1). However, a continuation of smoking after coronary revascularisation increased the risk of death markedly (HR 2.73, 95% CI 1.63–4.59, P< 0.001, Table 1). The population attributable fraction (the proportion of mortality in the population that is attributable to the risk factor) for smoking was 16.6% (95% CI 4.5–28.7%, P1⁄4 0.007). In accordance with current medical standards, all CAD patients are now treated increasingly aggressively with lipid-lowering medications, aspirin and antihypertensive therapies, as recommended in the guidelines. In addition, the treatment targets for blood pressure and LDL-cholesterol are continuously being lowered. As a result, many of the conventional, still important,