The Roles of AMPK in RevascularizationRead the full article
Cardiology Research and Practice publishes original research articles, review articles, and clinical studies focusing on the diagnosis and treatment of cardiovascular diseases, including hypertension, arrhythmia, heart failure, and vascular disease.
Dr. Terrence Ruddy is Director of Nuclear Cardiology at the University of Ottawa Heart Institute, and Professor of Medicine and Radiology at the University of Ottawa. His research is in SPECT and PET imaging techniques in cardiovascular disease.
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A Hypothetical Vascular Stent with Locally Enlarged Segment and the Hemodynamic Evaluation
Among the interventional stenting methods for treating coronary bifurcation lesions, the conventional treatments still have disadvantages, which include increased intervention difficulties or inadequate supply of blood flow to side branches and may alter the physiological function of downstream organs. Thus, the optimized design of stent geometry needs to be improved based on the specific shape of branches to minimize the complications of inadequate blood flow to the downstream organs and tissues. Our research used 3D modeling and fluid dynamics simulation to design and evaluate a new stent with locally enlarged segment by altering the proportion and length of enlarged surface area based on Bernoulli’s equation. The aim is to increase the pressure and blood flow supply at side branches. According to series of blood flow simulations, the stent with 10% enlargement of surface area and length of 3 folders of stent diameter was assigned as the optimized design. The results revealed that by using this design, according to the simulation results, the average pressure on side branches increased at the rate of 43.6%, which would contribute to the adequate blood supply to the downstream organs. Besides, the average wall shear stress (WSS) at sidewalls increased at 9.2% while the average WSS on the host artery wall decreased at 14.1%. There is in the absent of noticeable rise in the total area of low WSS that blows the threshold of 0.5 Pa. Therefore, the present study provides a new method to optimize the hemodynamics features of stent for bifurcation arteries.
Diagnostic Efficacy of Cardiac Scintigraphy with 99mTc-Pyrophosphate for Latent Myocardial Inflammation in Patients with Atrial Fibrillation
Objectives. This work aimed to study the efficacy of hybrid 99mTc-Pyrophosphate SPECT/CT for diagnosis of latent inflammatory processes in the myocardium of patients with atrial fibrillation (AF). Methods. The study comprised 34 patients aged 44 ± 9 years with AF of unknown etiology referred for radiofrequency ablation. The data were acquired using hybrid 99mTc-Pyrophosphate SPECT/CT. To evaluate and interpret the results of hybrid study and to determine localization of radiopharmaceutical accumulation, scintigraphic and CT images were fused. SPECT/CT results were compared with data of endomyocardial biopsy. Results. Sensitivity, specificity, and accuracy of 99mTc-Pyrophosphate SPECT/CT in diagnosing myocarditis were 91%, 100%, and 94%, respectively. Proposed diagnostic criteria for myocarditis comprised intensity of the radiopharmaceutical accumulation in the myocardium and the ratios of focus/lung, focus/vertebral column, and focus/LV pool. Minimum cutoff values for the histologically verified myocarditis were >1.47 for focus/lung index, >0.11 for focus/vertebral column ratio, and >1.26 for focus/lung index. Conclusions. SPECT/CT-based quantitative assessment of 99mTc-Pyrophosphate accumulation in the myocardium is a highly informative noninvasive method for diagnosis of inflammatory process in the heart in patients with AF of undefined etiology.
Body Mass Index and 1-Year Unplanned Readmission in Chinese Patients with Acute Myocardial Infarction: A Retrospective Cohort Study
Background. Evidence regarding the relationship between body mass index (BMI) and 1-year unplanned readmission was limited. Therefore, the objective of this research is to investigate whether BMI was independently related to 1-year unplanned readmission in Chinese patients with acute myocardial infarction (AMI) after percutaneous transluminal coronary intervention (PCI) after adjusting for other covariates. Methods. The present study was a cohort study. A total of 214 participants with AMI after PCI were involved in a hospital in China from 1st January 2017 to 1st January 2018. The target independent variable and the dependent variable were BMI measured at baseline and 1-year unplanned readmission, respectively. Covariates involved in this study included age, gender, TC, triglyceride, HDL-C, LDL-C, PT, APTT, INR, creatinine, HGB, LVEF, discharge medication, marital status, educational level, COPD, diabetes mellitus, heart failure, history of ischemic stroke, history of hemorrhagic stroke, arrhythmia, and hypertension. Results. The average age of 172 selected participants was 60.2 ± 10.8 years old, and about 68.6% of them was male. The rate of readmission in patients with AMI was 26.14%. The result of fully adjusted binary logistic regression showed BMI was negatively associated with risk of readmission after adjusting confounders (hazard ratio (HR) = 1.1, 95% CI 0.93–1.29). Nonlinear relationship was detected between BMI and 1-year unplanned readmission, whose point was 29.3. The effect sizes and the confidence intervals of the left and right sides of inflection point were 0.9 (0.7–1.2, for nonlinearity = 0.530) and 2.8 (1.3–5.8, for nonlinearity = 0.008), respectively. Conclusion. BMI has a nonlinear relationship with 1-year unplanned readmission in patients with myocardial infarction. The 1-year unplanned readmission rate of overweight patients (BMI > 29.3 kg/m2) has increased significantly. Obesity paradox does not exist in terms of readmission of Chinese patients with myocardial infarction after PCI.
Reconstruction of a lncRNA-Associated ceRNA Network in Endothelial Cells under Circumferential Stress
Background. Numerous studies have highlighted that long noncoding RNA (lncRNA) can indirectly regulate the expression of mRNAs by binding to microRNA (miRNA). LncRNA-associated ceRNA networks play a vital role in the initiation and progression of several pathological mechanisms. However, the lncRNA-miRNA-mRNA ceRNA network in endothelial cells under cyclic stretch is seldom studied. Methods. The miRNA, mRNA, and lncRNA expression profiles of 6 human umbilical vein endothelial cells (HUVECs) under circumferential stress were obtained by next-generation sequencing (NGS). We identified the differential expression of miRNAs, mRNAs, and lncRNAs using the R software package GDCRNATools. Cytoscape was adopted to construct a lncRNA-miRNA-mRNA ceRNA network. In addition, through GO and KEGG pathway annotations, we analyzed gene functions and their related pathways. We also adopted ELISA and TUNEL to investigate the effect of si-NEAT1 on endothelial inflammation and apoptosis. Results. We recognized a total of 32978 lncRNAs, 1046 miRNAs, and 31958 mRNAs in 6 samples; among them, 155 different expressed lncRNAs, 74 different expressed miRNAs, and 960 different mRNAs were adopted. Based on the established theory, the ceRNA network was composed of 13 lncRNAs, 44 miRNAs, and 115 mRNAs. We constructed and visualized a lncRNA-miRNA-mRNA network, and the top 20 nodes are identified after calculating their degrees. The nodes with most degrees in three kinds of RNAs are hsa-miR-4739, NEAT1, and MAP3K2. Functional analysis showed that different biological processes enriched in biological regulation, response to stimulus and cell communication. Pathway analysis was mainly enriched in longevity regulating, cell cycle, mTOR, and FoxO signaling pathway. Circumferential stress can significantly downregulate NEAT1, and after transducing si-NEAT1 for 24 h, inflammatory cytokine IL-6 and MCP-1 were significantly increased; furthermore, fewer TUNEL-positive cells were found in the si-NEAT1 treated group. Conclusions. The establishing of a ceRNA network can help further understand the mechanism of vein graft failure. Our data demonstrated that NEAT1 may be a core factor among the mechanical stress factors and that cyclic stress can significantly reduce expression of NEAT1, give rise to inflammation in the early stage of endothelial dysfunction, and promote EC apoptosis, which may play an essential role in vein graft failure.
Echocardiographic Predictors of All-Cause Mortality in Patients with Hypertrophic Cardiomyopathy following Pacemaker Implantation
Objectives. To examine the association between the echocardiographic parameters measured as left atrial diameter (LAD) and left ventricular end-diastolic diameter (LVEDD) and long-term risk of all-cause mortality in adults with hypertrophic cardiomyopathy (HCM) following pacemaker implantation. Methods. A total of 94 adult patients with HCM who underwent pacemaker implantation from November 2002 to June 2013 in our Arrhythmia Center for symptomatic bradycardia and did not receive an implantable cardiac defibrillator (ICD) or cardiac resynchronization therapy (CRT) during follow-up were retrospectively extracted. Results. After careful examination of the medical records, we retrospectively evaluated the clinical characteristics of 74 patients with LAD records (58.1 ± 14.9 years) and 76 patients with LVEDD records (57.6 ± 15.2 years). Based on the receiver-operating characteristic (ROC) curve, the values of LAD = 44 mm and LVEDD = 43 mm were identified to predict the all-cause mortality. In the Kaplan–Meier survival, LAD ≥44 mm and LVEDD ≥43 mm were both significantly associated with all-cause mortality (log-rank test ). Cox regression analysis indicated that LAD ≥44 mm (HR 3.580; 95% CI = 1.055–12.148; ) was an independent predictor of all-cause mortality, while LVEDD ≥43 mm was not significantly associated with all-cause mortality. LVOTO was also significantly associated with all-cause mortality (HR = 0.166; 95% CI = 0.036–0.771; ). Conclusions. In HCM patients with pacemaker implantation, LAD ≥44 mm was an independent predictor of all-cause mortality.
Intracardiac Fibrinolysis and Endothelium Activation Related to Atrial Fibrillation Ablation with Different Techniques
Objective. The effect of pulmonary vein isolation (PVI) on fibrinolytic and endothelial activation with currently applied periprocedural anticoagulation has not been explored. We measured markers of fibrinolysis and endothelium activation before and after PVI with the second-generation cryoballoon (Cryo), pulmonary vein ablation catheter (PVAC-Gold), and irrigated radiofrequency (IRF). Methods. Markers of fibrinolysis and endothelium activation in left atrial (LA) blood samples were measured in 31 patients before and after PVI (Cryo:10, PVAC-Gold: 7, IRF: 14). Periprocedural anticoagulation included uninterrupted vitamin K antagonist and iv heparin (ACT≥300 sec) during LA dwelling. Results. Levels of D-dimer (median; interquartile range, mgFEU/L) increased with all techniques (PVAC: 0.34; 0.24–0.50 versus 0.70; 0.61–1.31; , Cryo: 0.33; 0.28–0.49 versus 0.79; 0.65–0.93; ; IRF 0.33; 0.21–0.44 versus 0.83; 0.56–1.21; ). PAP complex level (ng/ml) increased after Cryo (247.3, 199.9–331.6 versus 270.9, 227.9–346.7; ) and IRF (265.3; 202.0–800.1 versus 325.6, 250.2–701.9; ), but not after PVAC (). PAI-1 activity (%) decreased with the PVAC (1.931; 0.508–3.859 versus 0.735, 0.240–2.707; ) and Cryo (0.361; 0.080–1.575 versus 0.378; 0.111–0.915; ). A similar trend was observed with IRF (). Both VWF antigen levels and FVIII activity increased after PVI with all the 3 techniques. The levels of soluble VCAM-1 (ng/ml) did not change after PVAC procedures, but increased after Cryo (542, 6; 428.5–753.1 versus 619.2; 499.8–799.0; ) and IRF (679.3; 505.0–744.7 versus 770.9; 631.9–894.0; ). Conclusion. PVI with contemporary ablation techniques and periprocedural antithrombotic treatment induces coagulation and endothelium activation of similar magnitude with different ablation methods.