CLINICAL STUDY: CARIOVASCULAR ULTRASOUND STUDIES
Is the mitral valve area flow-dependent in mitral stenosis?
A dobutamine stress echocardiographic study
Jagdish C. Mohan, MD*,
Ayan R. Patel, MD, FACC ,
Rajiv Passey, MD*,
Dinesh Gupta, MD*,
Manoj Kumar, MD*,
Ramesh Arora, MD* and
Natesa G. Pandian, MD, FACC ,*
* Department of Cardiology, G. B. Pant Hospital, New Delhi, India
Cardiovascular Imaging and Hemodynamic Laboratory, Tufts-New England Medical Center, Boston, Massachusetts, USA
Manuscript received May 30, 2002;
revised manuscript received July 12, 2002,
accepted August 1, 2002.
* Reprint requests and correspondence: Dr. Natesa G. Pandian, Cardiovascular Imaging and Hemodynamic Laboratory, Tufts-New England Medical Center, 750 Washington Street, Box 32, Boston, Massachusetts 02111, USA. npandian{at}lifespan.org
OBJECTIVES: The purpose of this study was to compare the effect of changes in flow rate on the mitral valve area (MVA) derived from two-dimensional echocardiographic planimetry and Doppler pressure half-time (PHT) methods in patients with mitral stenosis (MS).
BACKGROUND: Dobutamine stress echocardiography has been proposed as a means of assessing the severity of MS. However, data regarding the effect of an increase in flow rate on MVA are limited. If MVA is indeed flow-dependent, this has important implications for the assessment of the severity of MS, particularly in the setting of reduced cardiac output (CO).
METHODS: Dobutamine echocardiography was performed in 57 patients with isolated MS who were in sinus rhythm. The MVA was determined by planimetry and Doppler PHT methods.
RESULTS: Cardiac output increased by 50% in 27 patients (group I) and by <50% in 30 patients (group II). In group I, the MVA by planimetry increased by only 10.6 ± 2% and the MVA by PHT increased by 21.9 ± 4.8%. These changes were similar to those observed in group II (10.7 ± 3% and 14.8 ± 4%, respectively; p = NS), despite a much smaller increase in CO. A clinically important change (from the severe to mild category) occurred in only one patient when using the PHT method and in none by planimetry.
CONCLUSIONS: Changes in flow rate result in small but clinically insignificant changes in echocardiographic MVA measurement. These methods provide an accurate assessment of MS severity in a majority of patients, independent of changes in flow rate.
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Abbreviations and Acronyms
| | CO | | cardiac output | | HR | | heart rate | | LVOT | | left ventricular outflow tract | | MS | | mitral stenosis | | MVA | | mitral valve area | | PHT | | pressure half-time | | PHT-MVA | | mitral valve area measured by pressure half-time | | 2DE-MVA | | mitral valve area measured by two-dimensional echocardiography |
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