Immediate percutaneous coronary intervention (PCI) has long been associated with improved outcomes for STEMI patients presenting less than 12 hours after the onset of symptoms. If the patient presents 12 or more hours after symptom onset, however, is immediate PCI still more beneficial than delayed PCI?
That’s exactly the question a research team out of Korea hoped to answer, sharing its findings in Circulation: Cardiovascular Interventions.
“Given the importance of early timing of PCI in patients with STEMI who present within 12 hours, the recommendation for immediate PCI could be extended to late presenters with ongoing ischemia,” wrote lead author You-Jeong Ki, Seoul National University Hospital, and colleagues. “However, how to manage late presenters in general is unexplored, and evidence supporting the statements is limited.”
Using the Korea Acute Myocardial Infarction Registry, the group evaluated data from nearly 6,000 STEMI patients who were treated from November 2011 to December 2015. Patients were excluded if their symptom onset-to-door time (S-to-D time) could not be determined, they were initially treated with thrombolysis or they did not receive reperfusion therapy. Follow-up data for two full years were available for each patient.
Patients were separated into three groups: early presenters (S-to-D time of <12 hours), late presenters (S-to-D time of 12-48 hours) and very late presenters (S-to-D time of more than 48 hours). While a clear majority of patients (5,104) were early presenters, another 599 patients were late presenters and 265 patients were very late presenters. The authors also categorized each patient’s PCI as being either immediate (door-to-balloon time of 90 minutes or less) or delayed.
Overall, as is to be expected, early PCI was “significantly associated” with a lower major adverse cardiac event (MACE) rate when compared to delayed PCI.
Among late presenters and very late presenters, however, immediate PCI was not associated with an improvement in MACE rate.
“The mortality benefit of reperfusion therapy is greatest two to three hours after symptom onset through myocardial salvage,” the authors wrote. “Thereafter, the mortality benefit of reperfusion decreases with time. Hence, no viable myocardium may remain if significant time passes after the onset of myocardial infarction, and the affected myocardium may not be salvaged by immediate PCI although some hibernating myocardium may be saved by scheduled PCI.”
The full study is available here.
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.