Cardiovascular physiology in the older adults

Abstract

Journal of Geriatric Cardiology (2015) 12: 196−201 ©2015 JGC All rights reserved; www.jgc301.com Cardiovascular Care for Older Adults Open Access • Cardiovascular physiology in the older adults Xuming Dai 1 , Scott L Hummel 2 , Jorge B Salazar 3 , George E Taffet 4 , Susan Zieman 5 , Janice B Schwartz 6 Division of Cardiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Division of Cardiovascular Medicine, Department of Medicine, University of Michigan, Ann Arbor, MI Ann Arbor Veterans Affairs Health System, Ann Arbor, MI, USA Division of Cardiology, Mayo Clinic, Rochester, MN, USA Division of Geriatrics, Geriatrics and Cardiovascular Sciences, Houston Methodist Hospital, Baylor College of Medicine, Houston, TX, USA Division of Geriatrics and Clinical Gerontology, National Institute of Aging, Bethesda, MD, USA Divisions of Geriatrics and Clinical Pharmacology, Department of Medicine, University of California, San Francisco, CA, USA J Geriatr Cardiol 2015; 12: 196−201. doi:10.11909/j.issn.1671-5411.2015.03.015 Keywords: Aging; Cardiovascular disease; Left ventricular 1 Introduction In an aging society with persistent high prevalence of cardiovascular disease (CVD) in the elderly population, the health care system is facing an increasing challenge to ef- fectively care for these patients. However, due to the un- der-representation of CVD patients over 75 years of age in clinical trials, assessing safety and efficacy of diagnostic and therapeutic approaches, the evidence for managing eld- erly CVD patients is especially limited. Physiological chang- es of aging intertwined with pathophysiology of CVD, and comorbid conditions often complicate clinical management. With the rapid adoption in older patients of invasive car- diovascular procedures, such as percutaneous coronary in- tervention and trans-catheter aortic valve replacement, the magnitude of this challenge is increasing. Understanding key aspects of cardiovascular physiology in older adults can serve as a foundation to guide interpretations of clinical presentation, diagnostic responses, formulating therapeutic strategies, and monitoring clinical efficacy in elderly pa- tients with CVD. Advanced age is an important risk factor for cardiovas- cular disease, and a powerful independent predictor of car- diovascular morbidity, mortality and disability. As a result of decades of complex molecular and cellular aging proc- Correspondence to: Janice B Schwartz, MD, Department of Medicine, University of California, San Francisco, California, CA, USA. E-mail: janice.schwartz@ucsf.edu Telephone: +1- 415-4061573 Fax: +1-415-4061577 Received: April 8, 2015 Revised: April 30, 2015 Accepted: May 7, 2015 Published online: May 15, 2015 esses, cardiovascular physiology in the older adult is char- acterized by: (1) endothelial dysfunction, (2) increased arte- rial stiffness, (3) increased left ventricular (LV) stiffness, (4) altered coupling of LV and arterial stiffness and function, (5) attenuated baroreflex and autonomic reflexes, and (6) de- generative changes of the conduction system. These chan- ges produce a cardiovascular system that has reduced max- imal function compared to younger people and less reserve capacity, and can fail to meet needs when stressed. The purpose of this paper is to highlight the changes in the vasculature and heart that impact on the basal and stressed physiology of the older patient with cardiovascular disease. 2 Endothelial dysfunction 2.1 Physiology and age-related changes The endothelium plays an active role in maintaining vascular homeostasis by balancing vasodilation and vaso- constriction, growth inhibition and promotion, anti- and pro-thrombosis, anti- and pro-inflammation, and anti- and pro-oxidation. Endothelial cells secrete various vasoactive molecules such as the vasodilators, nitric oxide (NO), prostacyclin, and endothelium-derived hyperpolarizing fac- tor, and vasoconstrictors, such as endothelin-1, angiotensin II and thromboxane A 2 . The most frequently used tool to investigate age-related changes in endothelial function is NO mediated vasodilatation. Age-related decreases in NO-mediated vasodilatory responses are well documented at every level of the vasculature from the coronary mi- cro-circulation to larger epicardial coronary arteries and the peripheral circulation. [1] Endothelial-dependent forearm va- http://www.jgc301.com; jgc@jgc301.com | Journal of Geriatric Cardiology