Comparison of Ticagrelor with Clopidogrel on Coronary Microvascular Dysfunction Following Acute Myocardial Infarction Using Angiography-Derived Index of Microcirculatory Resistance.

PURPOSE: This research aimed to assess the impact of ticagrelor and clopidogrel on coronary microvascular dysfunction (CMD) and prognosis following acute myocardial infarction (AMI), using the angiography-derived index of microcirculatory resistance (angio-IMR) as a non-invasive assessment tool. METHODS: In this retrospective study, angio-IMR was performed to evaluate CMD before and after dual antiplatelet therapy (DAPT) with either ticagrelor (90 mg twice daily, n = 184) or clopidogrel (75 mg once daily, n = 72). The primary endpoint is the improvement of CMD evaluated by angio-IMR (delta angio-IMR) following DAPT. Secondary endpoints included myocardial reinfarction and readmission for heart failure during 2-year follow-up. RESULTS: Compared with clopidogrel, ticagrelor exhibited a significantly higher delta angio-IMR [- 3.09 (5.14) versus - 1.99 (1.91), P = 0.008], indicating a superior improvement of CMD with ticagrelor treatment. Multivariate Cox regression indicated that ticagrelor treatment was related to a reduced risk of readmission for heart failure [8 (4.3) versus 9 (12.5), adjusted HR = 0.329; 95% CI = 0.116-0.934; P = 0.018] and myocardial reinfarction [7 (3.8) versus 8 (11.1), adjusted HR = 0.349; 95% CI = 0.125-0.975; P = 0.026]. Furthermore, ticagrelor treatment serves as an independent predictor of readmission for heart failure (HR = 0.322; 95% CI = 0.110-0.943; P = 0.039). CONCLUSION: The results of this study indicate a potential association between ticagrelor treatment and improved CMD, as well as a reduced risk of cardiovascular events, including myocardial reinfarction and readmission for heart failure in AMI patients. Further randomized controlled trials are necessary to confirm the potential benefits of ticagrelor on CMD and cardiovascular prognosis. This clinical trial was registered in www. CLINICALTRIALS: gov (NCT05978726).

Prognostic Value of Coronary Angiography-Derived Index of Microcirculatory Resistance in Non-ST-Segment Elevation Myocardial Infarction Patients.

BACKGROUND: The index of microcirculatory resistance is a reliable measure for evaluating coronary microvasculature, but its prognostic value in patients with non-ST-segment elevation myocardial infarction (NSTEMI) remains unclear. OBJECTIVES: This study aimed to evaluate the prognostic impact of postpercutaneous coronary intervention (PCI) angiography-derived index of microcirculatory resistance (angio-IMR) in patients with NSTEMI. METHODS: The culprit vessel's angio-IMR was measured after PCI in 2,212 NSTEMI patients at 3 sites. The primary endpoint was 2-year major adverse cardiac events (MACEs), defined as a composite of cardiac death, readmission for heart failure, myocardial reinfarction, and target vessel revascularization. RESULTS: The mean post-PCI angio-IMR was 20.63 ± 4.17 in NSTEMI patients. A total of 206 patients were categorized as the high post-PCI angio-IMR group according to maximally selected log-rank statistics. Patients with angio-IMR >25 showed a higher rate of MACEs than those with angio-IMR ≤25 (32.52% vs 9.37%; P < 0.001). Post-PCI angio-IMR >25 was an independent predictor of MACEs (HR: 4.230; 95% CI: 3.151-5.679; P < 0.001) and showed incremental prognostic value compared with conventional risk factors (AUC: 0.774 vs 0.716; P < 0.001; net reclassification index: 0.317; P < 0.001; integrated discrimination improvement: 0.075; P < 0.001). CONCLUSIONS: In patients undergoing PCI for NSTEMI, an increased post-PCI angio-IMR is associated with a higher risk of MACEs. The addition of post-PCI angio-IMR into conventional risk factors significantly improves the ability to reclassify patients and estimate the risk of MACEs. (Angiograph-Derived Index of Microcirculatory Resistance in Patients With Acute Myocardial Infarction; NCT05696379).

Combined risk estimates of diabetes and coronary angiography-derived index of microcirculatory resistance in patients with non-ST elevation myocardial infarction.

BACKGROUND: Diabetes mellitus (DM) and coronary microvascular dysfunction (CMD) increase the risk of adverse cardiac events in patients with non-ST-segment elevation myocardial infarction (NSTEMI). This study aimed to evaluate the combined risk estimates of DM and CMD, assessed by the angiography-derived index of microcirculatory resistance (angio-IMR), in patients with NSTEMI. METHODS: A total of 2212 patients with NSTEMI who underwent successful percutaneous coronary intervention (PCI) were retrospectively enrolled from three centers. The primary outcome was a composite of cardiac death or readmission for heart failure at a 2-year follow-up. RESULTS: Post-PCI angio-IMR did not significantly differ between the DM group and the non-DM group (20.13 [17.91-22.70] vs. 20.19 [18.14-22.77], P = 0.530). DM patients exhibited a notably higher risk of cardiac death or readmission for heart failure at 2 years compared to non-DM patients (9.5% vs. 5.4%, P < 0.001). NSTEMI patients with both DM and CMD experienced the highest cumulative incidence of cardiac death or readmission for heart failure at 2 years (24.0%, P < 0.001). The combination of DM and CMD in NSTEMI patients were identified as the most powerful independent predictor for cardiac death or readmission for heart failure at 2 years (adjusted HR: 7.894, [95% CI, 4.251-14.659], p < 0.001). CONCLUSIONS: In patients with NSTEMI, the combination of DM and CMD is an independent predictor of cardiac death or readmission for heart failure. Angio-IMR could be used as an additional evaluation tool for the management of NSTEMI patients with DM. TRIAL REGISTRATION: URL: https://www. CLINICALTRIALS: gov ; Unique identifier: NCT05696379.

Exosomes and Exosomal Cargos: A Promising World for Ventricular Remodeling Following Myocardial Infarction.

Exosomes are a pluripotent group of extracellular nanovesicles secreted by all cells that mediate intercellular communications. The effective information within exosomes is primarily reflected in exosomal cargos, including proteins, lipids, DNAs, and non-coding RNAs (ncRNAs), the most intensively studied molecules. Cardiac resident cells (cardiomyocytes, fibroblasts, and endothelial cells) and foreign cells (infiltrated immune cells, cardiac progenitor cells, cardiosphere-derived cells, and mesenchymal stem cells) are involved in the progress of ventricular remodeling (VR) following myocardial infarction (MI) via transferring exosomes into target cells. Here, we summarize the pathological mechanisms of VR following MI, including cardiac myocyte hypertrophy, cardiac fibrosis, inflammation, pyroptosis, apoptosis, autophagy, angiogenesis, and metabolic disorders, and the roles of exosomal cargos in these processes, with a focus on proteins and ncRNAs. Continued research in this field reveals a novel diagnostic and therapeutic strategy for VR.