Repeated Balloon Inflations Do Not Diminish ST Segment Elevation even though Coronary Collateral Recruitment Is Promoted in Pigs

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Abstract

Objective: Attempts to demonstrate preconditioning during repeated angioplasty balloon inflations (BIs) have not been universally successful. The main obstacle is that the first BI is unreliable, due to the variable degrees of occlusion by the deflated balloon. In the present study, we examined whether ST segment elevation decreases and evaluated its relation to collateral recruitment during repeated angioplasty BIs in the pig. Methods and Results: Twenty male pigs, 7 months old, under general anesthesia, underwent 3 repeated BIs of 120 s, with a 5-min interval between them, in the left anterior descending artery or the right coronary artery. A pressure wave wire was used for the measurement of coronary wedge pressure and to obtain the intracoronary ST segment elevation. Intracoronary ST segment elevation was 1.97 ± 0.76 mV during the 1st BI, 2.09 ± 0.82 mV during the 2nd BI and 1.84 ± 0.82 mV during the 3rd BI (p = n.s.). Coronary wedge pressure was 12 ± 6, 18 ± 18 and 20 ± 20 mm Hg (p < 0.05 vs. 1st BI) during the 3 BIs, respectively. Conclusion: Repeated BIs do not diminish ST segment elevation in the pig model, even though coronary collateral recruitment is promoted.

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Is the development of myocardial tolerance to repeated ischemia in humans due to preconditioning or to collateral recruitment?

Michael Billinger, Martin Fleisch, Franz Eberli … (1999)

The purpose of this study in patients with quantitatively determined, poorly developed coronary collaterals was to assess the contribution of ischemic as well as adenosine-induced preconditioning and of collateral recruitment to the development of tolerance against repetitive myocardial ischemia. The development of myocardial tolerance to repeated ischemia is nowadays interpreted to be due to biochemical adaptation (i.e., ischemic preconditioning). In 30 patients undergoing percutaneous transluminal coronary angioplasty, myocardial adaptation to ischemia was measured using intracoronary (i.c.) electrocardiographic (ECG) ST segment elevation changes obtained from a 0.014-in. (0.036 cm) pressure guidewire positioned distal to the stenosis during three subsequent 2-min balloon occlusions. Simultaneously, an i.c. pressure-derived collateral flow index (CFI, no unit) was determined as the ratio between distal occlusive minus central venous pressure divided by the mean aortic minus central venous pressure. The study patients were divided into two groups according to the pretreatment with i.c. adenosine (2.4 mg/min for 10 min starting 20 min before the first occlusion, n = 15) or with normal saline (control group, n = 15). Collateral flow index at the first occlusion was not different between the groups (0.15 +/- 0.10 in the adenosine group and 0.13 +/- 0.11 in the control group, p = NS), and it increased significantly and similarly to 0.20 +/- 0.14 and to 0.19 +/- 0.10, respectively (p < 0.01) during the third occlusion. The i.c. ECG ST elevation (normalized for the QRS amplitude) was not different between the two groups at the first occlusion (0.25 +/- 0.13 in the adenosine group, 0.25 +/- 0.19 in the control group). It decreased significantly during subsequent coronary occlusions to 0.20 +/- 0.15 and to 0.17 +/- 0.13, respectively. There was a correlation between the change in CFI (first to third occlusion; deltaCFI) and the respective ST elevation shift (deltaST): deltaST = -0.02 to 0.78 x deltaCFI; r = 0.54, p = 0.02. Even in patients with few coronary collaterals, the myocardial adaptation to repetitive ischemia is closely related to collateral recruitment. Pharmacologic preconditioning using a treatment with i.c. adenosine before angioplasty does not occur. The variable responses of ECG signs of ischemic adaptation to collateral channel opening suggest that ischemic preconditioning is a relevant factor in the development of ischemic tolerance.

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Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: a prospective study.

Alain Cribier, Luis Korsatz, René Koning … (1992)

The goal of the study was to evaluate the progressive increase in ischemic threshold with multiple sequential transient coronary occlusions and to assess the role of the collateral circulation in adaptation to ischemia. It has been observed that the duration of balloon inflations during coronary angioplasty can be gradually prolonged during subsequent dilations with a reduction in patient symptoms and diminished ischemic electrocardiographic (ECG) changes. Although the mechanism has not been fully explained, recruitment of coronary collateral circulation induced by repeated coronary occlusion has been reported. The stimuli for recruitment and the natural history of coronary collateral circulation are not understood. Seventeen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricle were enrolled. Angioplasty consisted of five successive prolonged inflations. Sequential changes in clinical, intracoronary ECG and left ventricular indexes of myocardial ischemia were examined. Coronary collateral channels were evaluated during balloon inflations by ipsilateral and contralateral injections of contrast medium and hemodynamically by occlusion pressure. An improved tolerance to myocardial ischemia with repetitive coronary occlusions was demonstrated by a significant reduction of angina, ST segment deviation, left ventricular filling pressure and less impairment of ejection fraction. Left ventricular wall motion abnormalities remained unchanged. Collateral angiographic grade did not change in 7 patients and increased in 10. This study confirms a progressive adaptation of myocardial ischemia to repetitive coronary occlusions and supports the concept that sequential episodes of myocardial ischemia are a stimulating factor for the recruitment of collateral channels in humans. These results also suggest that enhancement of recruitable collateral circulation might be an underlying mechanism of myocardial ischemic preconditioning.

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Electrophysiological Characteristics of Repetitive Ischemic Preconditioning in the Pig Heart

M Shattock (1996)

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Author and article information

Journal

Journal ID (publisher-id): CRD

Journal ID (nlm-ta): Cardiology

Journal ID (doi): 10.1159/issn.0008-6312

Title: Cardiology

Publisher: S. Karger AG

ISSN (Print): 0008-6312

ISSN (Electronic): 1421-9751

Publication date Subscription-year: 2007

Publication date (Print): November 2007

Publication date (Electronic): 13 February 2007

Volume: 108

Issue: 4

Pages: 340-344

Affiliations

^aSecond Department of Cardiology, Hellenic Red Cross Hospital, ^bElpen Experimental Laboratory, ^cCardiovascular Research Institute, and ^dOnassis Cardiac Center, Athens, Greece

Article

Publisher ID: 99106 Other ID: Cardiology 2007;108:340–344

DOI: 10.1159/000099106

PubMed ID: 17299262

SO-VID: fbc61e04-dbd2-4ad2-8e67-9537f6364592

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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.

History

Date received : 19 April 2006

Date accepted : 19 October 2006

Page count

Figures: 2, Tables: 1, References: 15, Pages: 5

Repeated Balloon Inflations Do Not Diminish ST Segment Elevation even though Coronary Collateral Recruitment Is Promoted in Pigs

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Abstract

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Karger: Cardiovascular System

Most cited references 6

Is the development of myocardial tolerance to repeated ischemia in humans due to preconditioning or to collateral recruitment?

Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: a prospective study.

Electrophysiological Characteristics of Repetitive Ischemic Preconditioning in the Pig Heart

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