Document Detail

Myocardial blood flow in patients with low-flow, low-gradient aortic stenosis: differences between true and pseudo-severe aortic stenosis. Results from the multicentre TOPAS (Truly or Pseudo-Severe Aortic Stenosis) study.
MedLine Citation:
PMID:  18381378     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity. OBJECTIVES: To investigate whether myocardial blood flow (MBF) and MFR differ in low-flow, low-gradient AS depending on whether there is underlying true-severe AS (TSAS) or pseudo-severe AS (PSAS). METHODS: In 36 patients with low-flow, low-gradient AS, dynamic [13N]ammonia PET perfusion imaging was performed at rest (n = 36) and during dipyridamole stress (n = 20) to quantify MBF and MFR. Dobutamine echocardiography was used to classify patients as TSAS (n = 18) or PSAS (n = 18) based on the indexed projected effective orifice area (EOA) at a normal flow rate of 250 ml/s (EOAI(proj )<or= or >0.55 cm(2)/m(2)). RESULTS: Compared with healthy controls (n = 14), patients with low-flow, low-gradient AS had higher resting mean (SD) MBF (0.83 (0.21) vs 0.69 (0.09) ml/min/g, p = 0.001), reduced hyperaemic MBF (1.16 (0.31) vs 2.71 (0.50) ml/min/g, p<0.001) and impaired MFR (1.44 (0.44) vs 4.00 (0.91), p<0.001). Resting MBF and MFR correlated with indices of AS severity in low-flow, low-gradient AS with the strongest relationship observed for EOAI(proj) (r(s) = -0.50, p = 0.002 and r(s) = 0.61, p = 0.004, respectively). Compared with PSAS, TSAS had a trend to a higher resting MBF (0.90 (0.19) vs 0.77 (0.21) ml/min/g, p = 0.06), similar hyperaemic MBF (1.16 (0.31) vs 1.17 (0.32) ml/min/g, p = NS), but a significantly smaller MFR (1.19 (0.26) vs 1.76 (0.41), p = 0.003). An MFR <1.8 had an accuracy of 85% for distinguishing TSAS from PSAS. CONCLUSIONS: Low-flow, low-gradient AS is characterised by higher resting MBF and reduced MFR that relates to the AS severity. The degree of MFR impairment differs between TSAS and PSAS and may be of value for distinguishing these entities.
I G Burwash; M Lortie; P Pibarot; R A de Kemp; S Graf; G Mundigler; A Khorsand; C Blais; H Baumgartner; J G Dumesnil; Z Hachicha; J DaSilva; R S B Beanlands
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Publication Detail:
Type:  Journal Article; Multicenter Study; Research Support, Non-U.S. Gov't     Date:  2008-04-01
Journal Detail:
Title:  Heart (British Cardiac Society)     Volume:  94     ISSN:  1468-201X     ISO Abbreviation:  Heart     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-11-17     Completed Date:  2009-01-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9602087     Medline TA:  Heart     Country:  England    
Other Details:
Languages:  eng     Pagination:  1627-33     Citation Subset:  AIM; IM    
Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
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MeSH Terms
Aortic Valve Stenosis / diagnosis*,  physiopathology
Blood Flow Velocity / physiology
Case-Control Studies
Coronary Circulation / physiology*
Echocardiography, Stress
Positron-Emission Tomography
Young Adult
Comment In:
Heart. 2008 Dec;94(12):1526-7   [PMID:  18669547 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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