Many patients who quit smoking after percutaneous coronary intervention (PCI) go on to have long-term cardiovascular outcomes comparable to patients who never smoked at all, according to new research published in European Heart Journal.[1] This encouraged the study’s authors, who had feared any history of smoking regularly would do permanent, irreversible damage.
The analysis focused on data from more than 74,000 patients who underwent PCI from 2009 to 2016 in South Korea. Within the first year of PCI, each patient told their healthcare providers if they were current smokers, ex-smokers or nonsmokers. Their cardiovascular health was then tracked for a total of approximately four years.
While 45.4% of patients were nonsmokers after PCI, 38.5% were ex-smokers and 16.1% were current smokers. While nonsmokers were more likely to be older, current smokers were more likely to younger. Also, ex-smokers were less likely to present with diabetes, and current smokers were more likely to present with diabetes, higher fasting glucose, higher total cholesterol or higher triglyceride levels.
Overall, the study’s primary outcome of major adverse cardiovascular and cerebrovascular events (MACCE)—a composite of all-cause mortality, myocardial infarction, coronary revascularization and stroke four years after PCI—was seen in 19.3% of patients. The outcome was 19.8% more likely among patients who continued smoking after PCI compared to nonsmokers—and a similar difference was seen between current smokers and ex-smokers.
Perhaps the biggest takeaway from the team’s analysis was that patients who stopped smoking after PCI and had accumulated less than 20 “pack years” in their lives had cardiovascular outcomes comparable to patients who never smoked at all. However, when a patient had accumulated more than 20 pack years—a sign that they were a heavy smoker for a long period of time—it became harder for them to reverse the harm smoking had done to their health. These patients had a 20% higher MACCE rate than non-smokers, comparable to current smokers.
“From the beginning of this study, my colleagues and I, as clinical researchers, suspected that there could be a threshold for irreversible harm resulting from smoking,” senior author Jung-Kyu Han, an internal medicine specialist with Seoul National University Hospital in South Korea, said in a prepared statement. “Yet, the revelation that this threshold lies around 20 pack years—not just five or 10 pack years—was an encouraging discovery. It suggests that smokers undergoing PCI, who have not reached a cumulative smoking exposure of 20 pack years, may still have an opportunity to evade the lasting detrimental effects on their cardiovascular outcomes caused by smoking.”
Click here to read the full study in European Heart Journal, a publication of the European Society of Cardiology.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.