Role of Trimethylamine N‐Oxide in Assessing Plaque Instability of the Culprit Lesion in Chinese Patients With ST‐Elevation Myocardial Infarction: Insights From a 7‐Year Long‐Term Follow‐Up Study

This study investigated the relationship between trimethylamine N‐oxide (TMAO) levels and plaque instability in Chinese patients with ST‐elevation myocardial infarction (STEMI) using optical coherence tomography (OCT), with a 7 ‐year follow‐up. Between January 1, 2017, and December 31, 2018, 188 Chinese patients with STEMI who underwent OCT at the Second Affiliated Hospital of Harbin Medical University were enrolled. Patients were stratified into low TMAO (≤ 2.54 μM) and high TMAO (> 2.54 μM) groups. The primary endpoint was major adverse cardiovascular events (MACE: all‐cause mortality, reinfarction, target vessel revascularization, and stroke). Compared with the low TMAO group, the high TMAO group showed a higher incidence of plaque rupture and a lower incidence of plaque erosion. Laboratory findings revealed significantly elevated NT‐proBNP levels in the high TMAO group. OCT analyzes demonstrated greater plaque length and more frequent microchannels in the high TMAO group. During follow‐up, both TMAO and NT‐proBNP were independently associated with 7‐year MACE. Receiver operating characteristic analysis identified TMAO as a predictor of MACE, with a sensitivity of 59.5% and a specificity of 65.8%. In conclusion, elevated TMAO levels were associated with adverse plaque characteristics and independently predicted long‐term cardiovascular events in Chinese STEMI patients. These findings suggest that TMAO may serve as a valuable biomarker for assessing plaque instability and improving risk stratification in this population.