[Antithrombotic therapy in the elderly patient]

In 1994 there were about 100,000 deaths in Portugal (99.621), most of these (43%) were caused by cardiocirculatory and cerebrovascular diseases. A revision about antithrombotic therapy in the elderly is completely justified by the importance of these numbers. In respect to oral anticoagulant therapy, special attention is given to its use in atrial fibrillation concerning the actual therapeutic levels. The current recommendations point to the use of INR levels inferior to those usually used. An INR superior to 2.0-3.0 is only used in the case of valvular mechanical prosthesis. Particular importance is given to the problem of therapeutic induction, mentioning the principal causes of fluctuation of dose/response to oral anticoagulants in the elderly, with special attention to the possible alterations of vitamin K metabolism and the therapeutic interference. Finally, we specify the hemorrhagic complications of this kind of antithrombotic treatment, and give the recommended measures for a practical action for patients with a high level of INR with or without hemorrhages. Concerning heparin therapy, an explanation of the action of heparin and the principal differences between standard heparin and low molecular weight heparins are presented. In the elderly, we point out the secondary effects, such as hemorrhages, thrombocytopenia induced by heparin and osteoporosis. The usual measures for its minimization are related to the recommended dose and type of heparin administered. Finally, we approach the problem of the antiplatelet therapy. The current knowledge is reviewed concerning its use in primary prevention and the minimum dose of aspirin that seems to be effective. The use of aspirin in primary prevention, even if it is not well specified, can be proposed, in a minimum dose, in the elderly with high vascular risk (among other associated factors). However, some particular cases must be studied because an identical clinical attitude cannot be accepted for all patients. The minimum effective dose of aspirin is now also known to be significantly inferior to the one that has been used. With the possible exceptions of atrial fibrillation and valvular prosthesis, aspirin seems to be effective in doses of approximately 75 to 150 mg/day. Other possibilities of antiplatelet therapy, are also analysed, with emphasis on platelet receptor inhibitors and metabolic inhibitors, even if their indications not yet been have completely established.