[Extracardiac risk factors in heart surgery--drugs]

Preoperative long-term medication continued during and after cardiac surgery may cause dangerous situations, including risks due to drug interactions, and risks as a result of contraindications to previously beneficial substances that develop during the surgical procedure. In the case of a lege-artis-performed anesthesia there is no urgent reason to postpone cardiac surgery because of previous drug treatment. Nevertheless, some compounds or groups of therapeutic agents can cause undue risk. These drugs are: acetylsalicylic acid (known to increase the bleeding tendency), and cardiac glycosides (which produces intraoperative dysrhythmias). Tricyclic antidepressants considerably intensify the effects of sympathomimetic agents. Monoamine-oxidase inhibitors, especially when combined with indirectly acting sympathomimetic agents or pethidine, may cause fluctuations of blood pressure that are difficult to control or can even precipitate a hypertensive crisis. In these cases preoperative discontinuation of drugs needs to be considered. The time of discontinuation must be chosen selectively for each active substance. The most important point for prevention of drug-related risk is to take a precise medical history, including previous drug treatment, in order to take future intraoperative precautions.