As many as one-fourth of heart attack patients who would normally have a stent implanted can forgo the procedure in favor of conservative management based on the results of optical coherence tomography (OCT), concluded U.S. researchers in a presentation at the European Society of Cardiology congress (ESC 2016) in Rome.
The study used OCT to differentiate plaque erosion from plaque rupture among 405 patients presenting at the emergency department and undergoing coronary angiography, said lead investigator Dr. Ik-Kyung Jang, PhD, from Harvard Medical School in Cambridge, Massachusetts, and Massachusetts General Hospital in Boston.
Distinguishing plaque rupture causes
About 60% of acute coronary syndrome (ACS) cases are caused by plaque rupture, but plaque erosion accounts for another 25% to 44% of cases. These cases have a distinct pathology that is amenable to antithrombotic therapy. OCT can tell the difference between the two.
OCT identified plaque erosion as the underlying pathology in 103 (25.4%) patients. Of these, 60 had a residual diameter stenosis of less than 70% on angiography, a thrombolysis in myocardial infarction (TIMI) flow grade of 3, and were stable without symptoms, the group reported.
These patients were cleared to receive antithrombotic medications alone without stent placement, and were treated with dual antiplatelet therapy (aspirin and ticagrelor), in addition to a glycoprotein IIb/IIIa inhibitor in 63.6%.
At a one-month follow-up, 47 of the 60 patients (78.3%) met the primary endpoint of the study, a greater than 50% reduction in clot size, with 22 patients having no visible clot at all, Jang reported. Overall clot volume decreased from 3.7 mm3 to 0.2 mm3 and minimal flow area increased from 1.7 mm2 to 2.1 mm2.
In the group without stenting, one patient died of gastrointestinal bleeding while on dual antiplatelet therapy; a second patient saw no improvement in the stenotic artery at one month.
Currently all patients with acute coronary syndrome are uniformly treated with stenting regardless of underlying pathology, the researchers said. This study is the first to show that patients with acute coronary syndrome due to erosion may benefit from a noninvasive approach relying on antithrombotic medications, Jang said.
The ability to identify erosion and pursue conservative management may lead to triaging patients away from invasive catheterization, the group concluded.
