Triglyceride glucose index combined with plaque characteristics as a novel biomarker for cardiovascular outcomes after percutaneous coronary intervention in ST-elevated myocardial infarction patients: an intravascular optical coherence tomography study

Abstract

Background and aim: This prospective study explored plaque morphology according to the underlying culprit lesion pathology (rupture versus erosion) in relation to the triglyceride glucose (TyG) index in patients with acute ST-elevated myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention and optical coherence tomography (OCT) for culprit lesions to elucidate the effects of the TyG index and type of plaque on the incidence of major adverse cardiovascular events (MACEs).

Methods and outcomes: A total of 274 patients with STEMI aged ≥ 18 years who underwent pre-intervention OCT imaging of culprit lesions between March 2017 and March 2019 were enrolled. The TyG index was calculated using the formula ln[fasting TG (mg/dL) × fasting glucose (mg/dL)/2]. Patients with plaque rupture (PR) and plaque erosion (PE) were divided into three groups across the TyG tertiles. MACEs were defined as a composite of all-cause death, myocardial infarction (MI) recurrence, and ischaemic stroke. In fully adjusted analyses, the middle tertile of TyG was significantly associated with greater rates of MACEs in patients with PR but not in those with PE (relative to the low tertile, HR [hazard ratio], 6.01; 95% confidence interval [CI], 1.25-28.88; P = 0.025). Cox regression models indicated a significantly higher HR for MACEs in patients in the middle tertile of TyG than in those in the low tertile of TyG after full additional adjustment (HR, 5.45; 95% CI, 1.10-27.09; P = 0.038). However, being in the high tertile of TyG independently and significantly increased the risk of major bleeding events among patients with PE (HR, 2.50; 95% CI, 1.11-5.65; P = 0.028). The area under the receiver operating characteristic curve for predicting MACEs to evaluate the diagnostic value of the TyG index combined with the morphological characteristics of plaque after full adjustment was 0.881 (sensitivity = 94.74%, specificity = 78.04%, cut-off level = 0.73). Kaplan-Meier curves were generated for the cumulative incidence of MACEs for up to a median of 1.98 years stratified by tertiles of TyG among the PR and PE subgroups. Among patients with PR, there were significant differences among the tertiles of TyG (p = 0.030).

Conclusion and relevance: Microstructural OCT features of culprit lesions in combination with the TyG index, a surrogate estimate of insulin resistance, can be used in clinical practice to support risk stratification and predict adverse events in patients with STEMI.

Conflict of interest statement

1. Non-financial competing interests. 2. Non-financial competing interests include family associations, political, religious, academic or any other.

Figures

Fig. 1

Representative cross-sectional optical coherence tomography images. A Thin-cap fibroatheroma was defined as a lipid-rich plaque (lipid identified as signal poor and attenuating) of more than two quadrants of vessel lumen with a fibrous cap (identified as signal rich, or brightly reflecting, with low attenuation) thickness measuring 65 mm or less. (arrow). B Lipid plaque (arrow) most often appears as diffusely bordered, signal-poor regions with overlying signal-rich bands. C Macrophage infltration (arrow) defned as a signal-rich, distinct or confuent punctate region of higher intensity than background speckle noise that generates remarkable backward shadowing. D Plaque rupture identified by disruption of the fibrous cap and cavity formation (asterisk). E Plaque erosion identified by the presence of attached thrombus (asterisk) overlying an intact plaque. F Microvessels defined as tubule luminal structures that do not generate a signal, with no connection to the vessel lumen (arrow). G Red thrombus consists mainly of red blood cells; relevant OCT images are characterized as high-backscattering protrusions with signal free shadowing (asterisk). White thrombi mainly consisted of white blood cells (WBCs) and platelets and were characterized as signal-rich, low-backscattering, billowing projections protruding into the lumen (asterisk). H Cholesterol crystal (arrow) identified by linear, highly backscattering structures without remarkable backward shadowing

Fig. 2

Flow chart 2 Study flow chart. OCTAMI, Optical Coherence Tomography Examination in Acute Myocardial Infarction; OCT optical coherence tomography, AMI acute myocardial infarction

Fig. 3

Bar graphs of optical coherence tomography findings of coronary plaques between groups. Comparisons of the incidence of plaque rupture, showed significant differences between patients in TyGlow and TyGmid. Comparisons of the incidence of patients without mixed plaque and patients without lipid plaque showed significant differences between patients in the in TyGlow, TyGmid and TyGhigh. However, there are no significant differences among patients with plaque erosion

Fig. 4

Receiver operating characteristic curve of triglyceride glucose index combined with plaque characteristics for predicting MACES. The area under the ROC was 0.88 (95% CI, 0.84–0.92; this figure). The Youden index was 0.73 and corresponding sensitivity and specificity were 94.74% and 78.04%. MACEs, major adverse cardiovascular events; AUC, areas under the ROC curve; CI, 95% confidence interval

Fig. 5

Kaplan-Meier curves showing cumulative MACE rates for up to median 1.98 years stratified by the tertiles level of TyG characteristic among patients with plaque rupture and erosion. A Kaplan–Meier curves showing cumulative MACE rates stratified by the level of TyG among patients with plaque rupture. TyG_Tertiles = 1 represents the patients with low level of TyG among patients with plaque rupture. TyG_Tertiles = 2 represents the patients with mudium level of TyG among patients with plaque rupture. TyG_Tertiles = 3 represent the patients with high level of TyG among patients with plaque rupture. B Kaplan–Meier curves showing cumulative MACE rates stratified by the level of TyG among patients with plaque erosion. TyG_Tertiles = 1 represents the patients with low level of TyG among patients with plaque erosion. TyG_Tertiles = 2 represents the patients with mudium level of TyG among patients with plaque erosion. TyG_Tertiles = 3 represent the patients with high level of TyG among patients with plaque erosion. MACE, major adverse cardiovascular events; TyG, TyG triglyceride glucose