The Atherogenic Dyslipidemia Complex and Novel Approaches to Cardiovascular Disease Prevention in Diabetes

Despite the effectiveness of low-density lipoprotein (LDL)-lowering strategies for the treatment of diabetic dyslipidemia, significant residual risk of atherosclerotic cardiovascular disease remains. Residual risk might in part be explained by lipid abnormalities that go beyond LDL cholesterol elevation, collectively termed the “atherogenic dyslipidemia complex (ADC),” consisting of hypertriglyceridemia, elevated small dense LDL particles, reduced high-density lipoprotein cholesterol, and high-density lipoprotein particle numbers, increased remnant lipoproteins, and postprandial hyperlipidemia. In this review, we briefly discuss the pathophysiology of the typical dyslipidemia that occurs in insulin-resistant states including obesity, the metabolic syndrome, and type 2 diabetes. Lipid-modifying strategies including lifestyle modification, ezetimibe, statins, fibrates, niacin, and cholesteryl ester transfer protein inhibitors in treating ADC are discussed. With the advent of novel therapies involving antisense oligonucleotides and monoclonal antibodies, new targets can be specifically downregulated to potentially promote lipoprotein clearance or suppress production. We review novel approaches currently undergoing clinical testing and we speculate on their suitability for use in treating ADC for the prevention of atherosclerotic cardiovascular disease. In addition, future targets that might be considered for therapeutic development are discussed.     

Heart Failure With Preserved Ejection Fraction in Diabetes: Mechanisms and Management

Diabetes mellitus (DM) is a major cause of heart failure in the Western world, either secondary to coronary artery disease or from a distinct entity known as “diabetic cardiomyopathy.” Furthermore, heart failure with preserved ejection fraction (HFpEF) is emerging as a significant clinical problem for patients with DM. Current clinical data suggest that between 30% and 40% of patients with HFpEF suffer from DM. The typical structural phenotype of the HFpEF heart consists of endothelial dysfunction, increased interstitial and perivascular fibrosis, cardiomyocyte stiffness, and hypertrophy along with advanced glycation end products deposition. There is a myriad of mechanisms that result in the phenotypical HFpEF heart including impaired cardiac metabolism and substrate utilization, altered insulin signalling leading to protein kinase C activation, advanced glycated end products deposition, prosclerotic cytokine activation (eg, transforming growth factor-β activation), along with impaired nitric oxide production from the endothelium. Moreover, recent investigations have focused on the role of endothelial-myocyte interactions. Despite intense research, current therapeutic strategies have had little effect on improving morbidity and mortality in patients with DM and HFpEF. Possible explanations for this include a limited understanding of the role that direct cell-cell communication or indirect cell-cell paracrine signalling plays in the pathogenesis of DM and HFpEF. Additionally, integrins remain another important mediator of signals from the extracellular matrix to cells within the failing heart and might play a significant role in cell-cell cross-talk. In this review we discuss the characteristics and mechanisms of DM and HFpEF to stimulate potential future research for patients with this common, and morbid condition.     

Insights on Atrial Fibrillation in Congenital Heart Disease

Patients with congenital heart disease (CHD) have been surviving late into adulthood, with atrial arrhythmias being the most common long-term complication. In recent reports, atrial fibrillation (AF) tended to be the most common form of arrhythmias among groups of patients with adult CHD (ACHD) older than 50 years of age. When compared with their adult counterparts without CHD, AF in patients with ACHD has been characterized by a higher incidence and prevalence, younger age of onset, and a greater risk of progression to persistent AF. Risk factors for the development of AF are not well known but include older age, left atrial dilation, systemic hypertension, and multiple cardiac surgeries. Data on management options such as optimal antiarrhythmic drug therapy, indications for anticoagulation, and efficacy and safety of catheter ablation are limited. There is a crucial need for further research exploring management, prevention, and monitoring strategies for the growing ACHD patient population with AF. This report will provide a contemporary review of the epidemiology, pathophysiology, and management options for AF in this complex patient population.