American Journal of Geriatric Cardiology最新文献

Myocardium is flexible when it comes to energy substrate utilization; it uses fatty acid, glucose, lactones, and ketones for its energy requirement. The myocardial energy substrate preference varies in a dynamic manner depending on myocardial perfusion, energy demand, substrate availability, and local/systemic hormonal changes. The authors discuss the metabolic perturbations seen in insulin-resistant myocardium and how they result in structural and other biochemical changes that ultimately result in left ventricular hypertrophy and diastolic and systolic dysfunction. The authors also discuss the utility of metabolic imaging to study metabolic derangement as seen in insulin-resistant rodents. The role of positron emission tomography and cine-magnetic resonance imaging coregistration in quantifying myocardial glucose uptake is demonstrated in fasted, 13-week old Sprague-Dawley rats under insulin-/glucose-stimulated conditions. This study demonstrates the utility of in vivo, noninvasive positron emission tomography and cine-magnetic resonance imaging modalities to longitudinally follow insulin resistance models during disease progression and after specific interventions.

Frailty is a progressive physiologic decline in multiple body systems marked by loss of function, loss of physiologic reserve, and increased vulnerability to disease and death. Until recently, frailty has been poorly defined in the medical literature. One currently accepted definition of frailty is having 3 of the following 5 attributes: unintentional weight loss, muscle weakness, slow walking speed, easy exhaustion, and low physical activity. The mechanisms that underline frailty remain unclear. Significantly higher levels of markers of inflammation and the clotting cascade have been found in frail persons compared with nonfrail persons. These markers are also risk factors for the development of coronary heart disease. Recent research has indicated that frailty is a clinical manifestation of cardiovascular disease, especially of heart failure. Thus, understanding the connection between frailty and cardiovascular disease may lead to development of new interventions that will prevent and reverse the associated morbidity and mortality.

Numerous epidemiologic and intervention trials, including many studying elderly cohorts, have demonstrated the importance of lipids in primary and secondary preventions of cardiovascular diseases, including coronary heart disease (CHD) and stroke. More recent studies have demonstrated that more intensive statin therapy that reduces low-density lipoprotein cholesterol levels to <70 to 80 mg/dL have resulted in more marked cardiovascular event reduction than less intensive statin treatment. The authors review the efficacy and safety of intensive vs less intensive statin therapy. Specifically, 4 such studies with sufficient data in elderly patients, including 2 trials of patients with stable CHD and 2 with acute coronary syndrome, demonstrating the efficacy and safety of intensive statin therapy with high-dose (80 mg) atorvastatin are reviewed in detail. Although elderly patients may be more susceptible to drug interactions when receiving high doses of statins, the present evidence supports the use of intensive statin therapy in most high-risk elderly patients both with stable CHD and following acute coronary syndrome.