The risk of recurrent myocardial infarction (MI) originating from an untreated lesion — or non-culprit lesion — was more than twice as high as the risk of reinfarction from a previously treated lesion among patients with MI who underwent percutaneous coronary intervention (PCI), according to results of the SWEDEHEART study presented Tuesday at Scientific Sessions.
Despite improvements in the care of patients with MI and a reduced mortality in recent years, one in five patients in unselected MI cohorts experience a new ischemic event — recurrent MI, stroke or death — within the first year after an MI, according to researcher Christoph Varenhorst, MD, PhD, of Uppsala Clinical Research Center and the Department of Medical Sciences, Cardiology, at Uppsala University in Sweden.
“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 MI,” Varenhorst said in an interview prior to Scientific Sessions.
Varenhorst and colleagues conducted a prospective cohort study in 99,546 patients with first MI enrolled in the Swedish Web-system for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) between January 2006 and December 2014. A culprit lesion was identified in 41,789 patients who underwent angiography. Reinfarction occurred in 3,603 patients, 597 originated from the culprit lesion and 1,193 originated from a non-culprit lesion.
The cumulative event probability for reinfarction within eight years related to a culprit lesion was 0.03 compared with 0.06 for a non-culprit lesion.
At index infarction, patients with subsequent culprit compared with non-culprit reinfarction were similar according to baseline characteristics including gender, age, infarction type, diabetic status, current smoking, hyperlipidemia and hypertension. However, the researchers did find that patients with culprit reinfarction were less likely to have 3-vessel disease at index (12 percent versus 18 percent) compared to patients with non-culprit reinfarction. Procedural characteristics including number of stents, total stent length and mean stent diameter were similar between the two groups.
“Although patients undergo a successful PCI for the coronary stenosis believed to need revascularization, a substantial proportion of patients experience recurrent MIs that do not originate from the treated lesion,” Varenhorst said. “This insight highlights that secondary prevention post-MI is not only indicated to prevent the patient from stent-related adverse events, but maybe even more to prevent overall coronary disease progression.”