Venous Thromboembolism in the Elderly:Introduction and Overview

Henry I. Bussey

The indications for anticoagulation therapy, the avail-able agents, and our knowledge about how best to man-age such therapy have increased dramatically over justthe last few years. Most of the indications for antico-agulation have a much higher prevalence in the elderlythan in younger patients. This makes the managementof such patients more challenging because the elderlyare more prone to thromboembolism, they may bemore sensitive to the effects of certain antithromboticagents, the pharmacokinetics of these agents may bealtered by the aging process, the elderly are at agreater risk of major bleeding, and they frequently aretaking more medications, a fact that increases the riskof drug interactions. We are very pleased to be able toprovide the readers of this journal with a categorizedbibliography of some of the best references in this areaprovided by national authorities in the clinical manage-ment of anticoagulation.

First, Dr. Fred Anderson, from the University ofMassachusetts Medical Center, provides us with se-lected references that address the epidemiology of ve-nous thrombosis in the elderly. Dr. Anderson is one ofthe pioneering investigators in this area, and it is hisown work that has demonstrated the marked increasein venous thrombosis among elderly hospitalized pa-tients.

The second section of bibliographical entries dealswith a number of areas related to warfarin use in theelderly. Dr. Ann Wittkowsky, from the University ofWashington Medical Center, provides us with an exten-sive list of selected references that address how thepharmacokinetics and pharmacodynamics of warfarinmetabolism in the elderly differs from what is seen inyounger patients. Next, Dr. Rebecca Beyth, from CaseWestern Reserve University, lists key references thatexamine the increased risk of bleeding related to theuse of warfarin in the elderly. Finally, Dr. Philip Han-sten, from the University of Washington School ofPharmacy, includes selected citations that cover thecritical area of warfarin drug interactions, which is aparticular concern in the elderly.

The fourth section deals with new information onthe use of unfractionated heparin, low molecularweight heparins, and heparinoids. Dr. Spinler and Ms.Evans, from Philadelphia College of Pharmacy and Sci-ence at the University of Pennsylvania, in addressingthe literature on several new agents, have taken aslightly different approach than that used by theauthors in the preceding section on warfarin. First,

they provide sources that address the effectiveness ofthese agents, followed by references on pharmacoki-netic differences in the elderly; and they conclude withcitations dealing with adverse reactions of theseagents in the elderly. Personal communication withthese authors indicate that they have concluded thatthe effectiveness of unfractionated heparin, low mo-lecular weight heparins, and heparinoids in the elderlyappear to be comparable with that seen in youngerpatients for either venous or arterial thromboem-bolism. They point out, however, that pharmacokinet-ics differences in the elderly may require a reductionin dosage of unfractionated heparin or low molecularweight heparin. Bleeding risks with these agents ap-pear to be higher in the elderly than in the young, butwhether the heparinoids exhibit such pharmacokineticdifferences or a higher bleeding risk in the elderlyremains to be established.

The ~nal section, by Dr. David Green and Dr. PaulaPodrazik from Northwestern University, provides se-lected citations dealing with the rapidly expandingarea of antiplatelet therapy in the elderly. Here again,the authors concluded that the organization of informa-tion was best managed in a slightly different format.The references they have selected are grouped into~ve categories: general reviews, drug interactions,pharmacokinetics and pharmacodynamics, adverse re-actions, and miscellaneous. As one might expect,within each of the ~ve categories, the selected refer-ences are further subdivided according to speci~c anti-platelet agents (i.e., aspirin, dipyridamole, ticlopidineand clopidogrel, glycoprotein IIb/IIIa inhibitors).Again, through personal communication with theseauthors, they pointed out that the major use of theseagents in the elderly is the prevention of myocardialinfarction, the treatment of cerebral transient ischemicattacks and ischemic strokes, and in maintainingpatency of coronary artery stents. In most cases, low-dose aspirin alone, ticlopidine alone, or the combinationhas been used. The safety and ef~cacy of a number ofpotent, new anti-platelet agents in the elderly needs tobe examined. The ~nal category of references in thissection (“miscellaneous”) provides some interestingreading on nonantithrombotic uses of these agents in

Address for correspondence: Henry I. Bussey, Pharm D, FCCP,Associate Professor, Division of Pharmacotherapy, The Univer-sity of Texas, Health Science Center, 7703 Floyd Curl Drive, SanAntonio, TX 78284-6200, USA

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Journal of Thrombosis and Thrombolysis 2000;9:111–112

© Kluwer Academic Publishers. Boston. Printed in the Netherlands.

the elderly, such as their effects on bone mineral den-sity and fracture risk, their relationship to the develop-ment of Alzheimer’s disease, and how their use mayin_uence the development of cataracts.

Whether for clinical practice, teaching activities, orin developing research initiatives, the hope is that thereader will ~nd this special issue a valuable resource oforganized references.

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