Untreated lesions twice as likely to cause 2nd heart attack

The risk of another heart attack following percutaneous coronary intervention (PCI) was twice as likely to originate from a previously untreated lesion versus the stented lesion, according to a study of a large Swedish cohort published in the Journal of the American Heart Association.

Lead researcher Christoph Varenhorst, MD, PhD, with the Uppsala Clinical Research Center, and colleagues studied 108,615 patients with first heart attacks between July 2006 and November 2014. Over a median follow-up of 3.2 years, another myocardial infarction (MI) occurred in 10.2 percent of patients. Of those who received PCI after the index MI, the re-MI was attributable to a non-culprit lesion (NCL) in 1,243 patients and to a culprit lesion (CL) in 655 patients. There were 1,566 re-MIs that couldn’t be categorized as NCL or CL events.

“A better understanding of long‐term disease progression and whether reinfarctions occur in previously treated (stented) lesions or in new or progressive lesions may have an impact on decisions on type and duration of medical treatment after an initial myocardial infarction,” Varenhorst and coauthors wrote.

The researchers noted patients were more likely to have a re-MI in a new lesion if they had multivessel disease, were men or had a longer duration between the first and second MI.

“Information on the extent of CAD (coronary artery disease) or the presence of multivessel disease is readily available from the index MI catheterization and, thus, likely useful for the prediction of reinfarctions not related to the CL,” they wrote.

Their findings differ with the previous PROSPECT study, which showed a near equal balance between CL-related adverse events (83) and NCL-related adverse events (74). The primary endpoint in PROSPECT included a composite of cardiac events (death from cardiac causes, cardiac arrest, MI, rehospitalization for unstable or progressive angina, revascularization and stent thrombosis) while their own study focused on MI.

“Improved stents, improved stenting techniques, and redefined antithrombotic treatment for the short‐term phase have had a substantial impact on stent‐related adverse outcomes, but perhaps this impact is less on overall disease progression and the risk of NCL‐related adverse outcomes,” Varenhorst et al. wrote.