Association of plasma trimethylamine N-Oxide level with healed culprit plaques examined by optical coherence tomography in patients with ST-Segment elevation myocardial infarction.

Background And Aims: Healed plaque is a hallmark of previous regional plaque rupture or erosion. We hypothesized that the plasma level of trimethylamine N-oxide (TMAO) is related to healed culprit plaque in ST-segment elevation myocardial infarction (STEMI) patients.

Methods And Results: A prospective cohort of 206 patients with STEMI, who were examined by optical coherence tomography (OCT) was enrolled in our study. After exclusion, 156 patients were categorized into healed plaque (n = 54) and nonhealed plaque (n = 102) groups. Plasma TMAO levels were detected by stable isotope dilution liquid chromatography tandem mass spectrometry in these two groups. Increased age and low BMI were more common in patients with healed plaques than in those without healed plaques. Through OCT observation, plaque rupture (81.5% vs. 45.1%, p < 0.001), thin cap fibroatheroma (TCFA) and macrophages (42.6% vs. 20.6%, p = 0.004, 70.4% vs. 26.5%, p < 0.001, respectively) were more frequently seen in patients with healed plaques than in those without healed plaques. The TMAO level in patients with healed plaques was significantly higher than that in patients with nonhealed plaques (3.9 μM [2.6-5.1] vs. 1.8 μM [1.0-2.7], p < 0.001). Furthermore, the receiver operating characteristic curve showed that TMAO can be used as a potential biomarker to predict healed plaque presence with a cutoff value of 2.9 μM (AUC = 0.810, sensitivity: 72.2%, specificity: 81.4%).

Conclusions: Healed plaque in STEMI patients is associated with a high level of plaque vulnerability and inflammation. A high level of plasma TMAO can be a useful biomarker to differentiate STEMI patients with healed culprit plaques.