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      Dihydropyridine Calcium Antagonists: Beneficial or Adverse Effects in the Setting of Myocardial Ischaemia/Reperfusion?

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          Abstract

          Dihydropyridine (DHP) calcium antagonists are established drugs in the management of hypertension and chronic stable angina. However, recently a dose-related increase in the mortality of patients with coronary artery disease with nifedipine has been suggested. The conclusions of this study were seriously contradicted. Therefore, in our laboratory, the effect of the DHP calcium antagonist nisoldipine on ischaemic myocardial blood flow and function, infarct size, and the functional recovery of reversibly injured, reperfused myocardium was once more investigated in controlled in vivo models. In anaesthetized dogs, in the presence of a severe coronary artery stenosis, intravenous nisoldipine decreased poststenotic subendocardial blood flow and contractile function when arterial pressure was decreased. In contrast, when hypotension was prevented by inflation of an intra-aortic balloon, no aggravation of myocardial ischaemia was seen. During exercise, when aortic pressure is raised by catecholamines, nisoldipine may therefore not exert a proischaemic effect, but may rather improve regional myocardial blood flow and function in the ischaemic region. As has been shown for nifedipine, the functional antagonism of α-adrenergic coronary vasomotor tone contributes to the improvement of myocardial blood flow and function of the ischaemic region, in particular during exercise. In anaesthetized pigs, intracoronary administration of nisoldipine prior to a 90-min low-flow ischaemia tended to decrease infarct size. Infarct size resulting from prolonged and severe myocardial ischaemia is reduced by one or more preceding short episodes of ischaemia and reperfusion, a phenomenon called ischaemic preconditioning. A transient exposure to exogenous calcium has been shown to mimic ischaemic preconditioning. Thus, a blockade of calcium channels may interfere with this reduction of infarct size. However, in anaesthetized pigs, nisoldipine did not prevent the reduction of infarct size by ischaemic preconditioning. Reperfused myocardium after short periods of myocardial ischaemia is characterized by a reversible, prolonged depression of myocardial function, a phenomenon called myocardial stunning. In anaesthetized dogs, preischaemic intravenous administration of nisoldipine improved the functional recovery of stunned myocardium following a 15-min complete occlusion of the left circumflex coronary artery. Since myocardial blood flow during myocardial ischaemia and reperfusion was not altered and afterload was kept constant by an intra-aortic balloon, the beneficial effect of nisoldipine appears to be related to an attenuated calcium overload during early myocardial ischaemia. In conclusion, proischaemic effects of calcium antagonists can be avoided when the dosage or mode of administration are adjusted to prevent significant decreases in arterial pressure. Patients in such a way under treatment with calcium antagonists will experience an increase in exercise tolerance and also a better recovery of contractile function after the termination of ischaemia

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          Author and article information

          Journal
          CRD
          Cardiology
          10.1159/issn.0008-6312
          Cardiology
          S. Karger AG
          978-3-8055-6464-9
          978-3-318-01953-7
          0008-6312
          1421-9751
          1997
          1997
          19 November 2008
          : 88
          : Suppl 1
          : 3-14
          Affiliations
          Department of Pathophysiology, University School of Medicine, Essen, Germany
          Article
          177451 Cardiology 1997;88:3–14
          10.1159/000177451
          9118166
          © 1997 S. Karger AG, Basel

          Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

          Page count
          Pages: 12
          Categories
          Session I

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