Quitting smoking after percutaneous coronary revascularization could achieve non-smoker risk level

A South Korean study on a large sample confirms that smokers who have undergone percutaneous coronary revascularization (PCR) have a higher risk than non-smokers of developing cardiovascular events. Quitting smoking, however, would reduce this risk in ex-smokers who have accumulated less than 20 pack-years of smoking.

The presence of nicotine, carbon monoxide and free radicals in tobacco smoke is the main cardiovascular risk factor in smokers. Quitting smoking is regularly presented as a way to reduce this cardiovascular risk.

Percutaneous coronary revascularization (PCR) involves dilating a narrowed coronary artery using a balloon that is inserted and inflated inside the artery at the site of the narrowing. A "stent" (a small metal spring) is then implanted at this site to maintain the result in the long term.[1]. However, large-scale data on the outcomes of patients who underwent this type of intervention, based on their smoking status, were lacking. South Korean researchers have now filled this gap.

After CPR, smokers would present more major cardiovascular events than non-smokers

Using data from the Korean National Health Insurance System (NHIS), the authors of this study analyzed the four-year medical follow-up of 74,471 patients who underwent CPR.[2]. These data provide access to various variables such as age, sex, high blood pressure, diabetes mellitus, body mass index, physical exercise, cardiac events and prescribed treatments. A self-administered questionnaire informing about smoking status and alcohol consumption made it possible to distinguish three groups: non-smokers (45.4 % of the sample), ex-smokers (38.5 %) and smokers (16.1 %). The mean age of this cohort was 62.5 years, 75.8 % of these patients being men.

The results of the study indicate that patients who remained smokers after a RCP would present more major cardiovascular and cerebrovascular events (MACCE) than non-smokers, as well as a higher rate of all-cause mortality. Ex-smokers would benefit, however, from a rate of MACCE equivalent to that of non-smokers. However, these benefits of quitting smoking are only significant below a previous consumption of 20 pack-years of smoking.[3] ; beyond this threshold, the MACCE rate of these ex-smokers (+20% compared to those who stopped) is not significantly different from that of persistent smokers.

Benefits of quitting smoking after a multidisciplinary team meeting

The NHIS database covers 97 % of the Korean population, the authors emphasize the interest of this large-scale study to confirm the cardiovascular consequences of smoking after a CPR. They highlight the usefulness of smoking cessation in patients who have undergone a CPR, especially since the chances of achieving complete smoking cessation are also greater for people who have undergone a CPR. Among the limitations of this study, the authors include the fact that the questionnaires were self-administered and that the count in pack-years does not allow to distinguish whether it is a question of smoking at low doses over the long term or at high doses in a short time.

Keywords: major cardiovascular events, percutaneous coronary revascularization (PCR), smoking cessation, smoker's paradox.

M.F.

[1] Coronary angioplasty, French Federation of Cardiology, updated May 21, 2021, consulted October 5, 2023.

[2] Ki YJ, Han K, Kim HS, Han JK, Smoking and cardiovascular outcomes after percutaneous coronary intervention: a Korean study, European Heart Journal, ehad616, Published online: 26 September 2023https://doi.org/10.1093/eurheartj/ehad616

[3] A pack-year corresponds to the consumption of 20 cigarettes per day for one year.