Search

Following myocardial ischemic injury, the most effective clinical intervention is timely restoration of blood perfusion to ischemic but viable myocardium to reduce irreversible myocardial necrosis, limit infarct size, and prevent cardiac insufficiency. However, reperfusion itself may exacerbate cell death and myocardial injury, a process commonly referred to as ischemia/reperfusion (I/R) injury, which primarily involves cardiomyocytes and cardiac microvascular endothelial cells (CMECs) and is characterized by myocardial stunning, microvascular damage (MVD), reperfusion arrhythmia, and lethal reperfusion injury. MVD caused by I/R has been a neglected problem compared to myocardial injury. Clinically, the incidence of microvascular angina and/or no-reflow due to ineffective coronary perfusion accounts for 5-50% in patients after acute revascularization. MVD limiting drug diffusion into injured myocardium, is strongly associated with the development of heart failure. CMECs account for > 60% of the cardiac cellular components, and their role in myocardial I/R injury cannot be ignored. There are many studies on microvascular obstruction, but few studies on microvascular leakage, which may be mainly due to the lack of corresponding detection methods. In this review, we summarize the clinical manifestations, related mechanisms of MVD during myocardial I/R, laboratory and clinical examination means, as well as the research progress on potential therapies for MVD in recent years. Better understanding the characteristics and risk factors of MVD in patients after hemodynamic reconstruction is of great significance for managing MVD, preventing heart failure and improving patient prognosis., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objectives: Percutaneous coronary interventions (PCIs) save countless acute myocardial infarction (AMI) patients. However, endothelial injury is still an inevitable complication. Circulating microparticles (MPs) play important roles in vascular dysfunction. Whether PCI affects function of MPs remains unclear., Methods: MPs were obtained from AMI patients (n = 38) both preoperatively and 24 h after PCI, and healthy subjects (n = 20). MPs origins were tested by flow cytometry. Rat thoracic aortas were incubated with MPs to determine the effects of MPs on phosphorylation of endothelial nitric oxide synthase (eNOS), caveolin-1 expression, eNOS association with heat shock protein 90 (Hsp90), generation of nitric oxide (NO) and superoxide anion (O2), and endothelial-dependent vasodilatation., Results: Compared with healthy subjects, MP concentrations increased in AMI patients. Undergoing PCI had no further effect on MPs concentration, but it results in increased endothelial-derived MPs proportion and decreased platelet-derived MP ratio. MPs from AMI patients decreased eNOS phosphorylation at Ser1177, increased eNOS phosphorylation at T495 and caveolin-1 expression, decreased eNOS association with Hsp90, decreased NO production but increased (O2) generation, damaged endothelial-dependent vasodilatation. All of these effects of MPs were strengthened by PCI., Conclusions: PCI further enhances the vascular injury effect of MPs. Circulating MPs may be a potential therapeutic target for patients undergoing PCI.

Background: The triglyceride-glucose (TyG) index is regarded as an independent predictor of cardiovascular (CV) consequences and a reliable surrogate measure of insulin resistance (IR). However, the predictive significance of the TyG index in patients with type 2 diabetes mellitus (T2DM) and ischemic cardiomyopathy (ICM) remains unknown. Methods: This study included 1514 consecutive subjects with ICM and T2DM. The tertile of the TyG index values was used to categorize these patients into three groups. Major adverse cardiac and cerebral events (MACCEs) were also noted. The TyG index was calculated using the [fasting triglycerides (mg/dL) × fasting plasma glucose (mg/dL)/2] equation. Results: After adjusting for age, BMI, and other potential confounders, the scores of multivariate Cox proportional hazards regression models for chest pain [9.056 (4.370 to 18.767), p< 0.001], acute myocardial infarction [4.437 (1.420 to 13.869), p=0.010], heart failure [7.334 (3.424 to 15.708), p< 0.001], cardiogenic shock [3.707 (1.207 to 11.384), p=0.022], malignant arrhythmia [5.309 (2.367 to 11.908), p< 0.001], cerebral infarction [3.127 (1.596 to 6.128), p< 0.001], gastrointestinal bleeding [4.326 (1.612 to 11.613), p=0.004], all-cause death [4.502 (3.478 to 5.827), p< 0.001] and cumulative incidence of MACCEs [4.856 (3.842 to 6.136), p< 0.001] increased significantly with an increase in TyG index levels (all p< 0.05). Time-dependent ROC analysis revealed that the area under the TyG index curve (AUC) reached 0.653 in the 3rd year, 0.688 in the 5th year, and 0.764 in the 10th year. The predictive efficiency of this model on MACCEs improved [net reclassification improvement (NRI): 0.361 (0.253 to 0.454); C-index: 0.678 (0.658 to 0.698); integrated discrimination improvement (IDI): 0.138 (0.098 to 0.175), all p< 0.05] following the incorporation of the TyG index into the base risk model. Conclusion: TyG index could be useful in predicting MACCEs and initiating preventive measures in subjects with ICM and T2DM. [ABSTRACT FROM AUTHOR]