Fall in aortic diastolic pressure immediately after aortic valve destruction can predict severity of regurgitation through the valve and chronic morphological changes in the left ventricle Takayasu Yamada 1 , Shunnosuke Handa 1 , Yumiko Wainai 1 , Tsutomu Yoshikawa 1 , Masahiro Suzuki 1 , Masato Tani 1 , Yoshiro Nakamura 1 , Kazutoshi Mizoi 2 1Cardiopulmonary Division, Department of Internal Medicine, School of Medicine, Keio University 2Keio University Ise Keio Hospital Keyword: 大動脈弁閉鎖不全症(aortic regurgitation) , 肥大(hypertrophy) , 心不全(heart failure) pp.1009-1014
Published Date 1990/10/15
DOI https://doi.org/10.11477/mf.1404910029
  • Abstract
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Aortic regurgitation (AR) has been studied ex-perimentally. however these reports did not inve-stigate compensatory mechanisms in AR in relation with the severity of regurgitation. If the severity of AR can be changed voluntarily, we can evaluate the pathophysiological response to AR in wide range. The purposes of this study were 1) to see if the extent of fall in aortic diastolic pressure im-mediately after the production of AR (ΔAoDP) was a reliable predictor of the severity of AR and 2) to evaluate the process of adaptation through acute and chronic stage in moderate AR in the rabbit model.

AR was produced by perforating the aortic va-lves in Japanese white rabbits. First, aortic pres-sure, volume, weight and wall thickness of the left ventricle were measured. Correlations between ΔAoDP and body weight-corrected volume (LVV/ BW) and weight (LVW/BW) were studied in 18 rabbits soon after, 19 one week after, 23 four weeks after and 10 eight weeks after the production of AR. ΔAoDP was closely correlated with LVV/BW after 1 week (1 week : R=0.667,p<0.01, 4 weeks : R=0.733, p<0.01, 8 weeks : R=0.757, p<0.05) and with LVW/BW after 4 weeks (4 weeks : R=0.484, p<0.05, 8 weeks : R=0.651, p<0.05). The slope of these regression equations increased with time ΔAoDP and LVV/BW : 1 week : 0.0138, 4 weeks : 0.0361, 8 weeks : 0.0577ml/kg?mmHg ; ΔAoDP and LVW/BW : 4 weeks : 0.0142, 8 weeks : O.0310 g/kg・mmHg). Second, serial morphological changes in the left ventricle in moderate AR in which ΔAoDP was between 15 and 40 mmHg were stu-died. LVV/BW progressively increased after 1 week. LVW/BW and FWd increased during 1 week to 4 weeks. After 8 weeks neither LVW/BW nor FWd had changed. Therefore the calculated wall stress of the left ventricle was larger after 8 weeks than after 4 weeks, which may lead to heart failure. We concluded that 1) ΔAoDP is a reliable predictor of the severity of AR and the following morpho-logical changes in the left ventricles and 2) the left ventricle adapts to acute volume loading by its enlargement and following hypertrophy, how-ever, these compensatory mechanisms might be inadequate 8 weeks after AR production.

Copyright © 1990, Igaku-Shoin Ltd. All rights reserved.


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