COMPLETE OCT Substudy: Non-Culprit Lesion Plaque Morphology in Patients With ST-Segment Elevation Myocardial Infarction

Findings from a new study presented at the American Heart Association 2019 Scientific Sessions in Philadelphia may explain the benefit of routine percutaneous coronary intervention (PCI) on obstructive non-culprit lesions in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease.

“Complete revascularization with routine PCI of non-culprit lesions after primary PCI improves outcomes in STEMI,” the researchers explained in their study abstract. “Whether non-culprit lesions are more commonly associated with vulnerable plaque morphology is unclear.”

In this prospective sub-study of the COMPLETE trial, researchers assessed the optical coherence tomography (OCT) of at least two major epicardial coronary arteries prior to non-culprit lesion PCI in 93 patients with STEMI and multi-vessel disease. The study categorized non-culprit lesions as either obstructive (≥70% stenosis by visual angiographic assessment) or non-obstructive and as thin cap fibroatheroma (TCFA) or non-TCFA. Overall, 47% of patients had at least one non-culprit lesion TCFA.

The study results showed that among 150 obstructive lesions, 39% were TCFAs and 61% were non-TCFAs. The researchers observed no differentiations in minimal lumen area (MLA) of obstructive TCFAs and non-TCFAs (1.9 vs. 1.7, P=0.52). However, they did find that compared with obstructive non-TCFAs, obstructive TCFAs contained a greater amount of lipid (78.4% vs. 36.5%, P<0.001), macrophages (94.8% vs. 52.2%, P<0.001), and cholesterol crystals (82.8% vs. 45.7%, P<0.001). Overall, the results showed that among 275 non-obstructive lesions, 27% were TCFAs and 73% were non-TCFAs.

“Almost one-half of patients with STEMI and multi-vessel disease harbor obstructive non-culprit lesions containing complex vulnerable plaque morphology,” the authors concluded.