Abstract | OBJECTIVES: We used color Doppler flow mapping to determine whether vena contracta width (VCW) is a load-independent measure of the severity of mitral regurgitation. BACKGROUND: VCW has been proposed to be a relatively load-independent measure of mitral regurgitation severity in flow models using a fixed orifice. However, in patients with mitral regurgitation, VCW may not be load independent because of a dynamic regurgitant orifice. METHODS: RESULTS: Systolic blood pressure (148 +/- 27 to 115 +/- 25 mm Hg) and end-systolic wall stress (121 +/- 50 to 89 +/- 36) decreased with nitroprusside (p < 0.05). Although nitroprusside did not significantly change mean values for VCW (0.5 +/- 0.2 to 0.5 +/- 0.2 cm), regurgitant volume (69 +/- 47 to 69 +/- 56 ml) or effective regurgitant orifice area (0.5 +/- 0.4 to 0.5 +/- 0.6 cm2), individual patients exhibited marked directional variability. Specifically, VCW decreased in 16 patients (improved mitral regurgitation), remained unchanged in 7 patients and increased in 8 patients (worsened mitral regurgitation) with nitroprusside. Also, the VCW response to nitroprusside was concordant with changes in effective regurgitant orifice area and regurgitant volume, and was not different between dynamic and fixed orifice groups. CONCLUSIONS: Contrary to the results from in vitro studies, VCW is not load independent in patients with mitral regurgitation caused by dynamic changes in the regurgitant orifice. The origin of mitral regurgitation does not predict accurately whether the regurgitant orifice is fixed or dynamic. Finally, short-term vasodilation with nitroprusside may significantly worsen the severity of mitral regurgitation in some patients.
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Authors | A M Kizilbash, D L Willett, M E Brickner, S K Heinle, P A Grayburn |
Journal | Journal of the American College of Cardiology
(J Am Coll Cardiol)
Vol. 32
Issue 2
Pg. 427-31
(Aug 1998)
ISSN: 0735-1097 [Print] United States |
PMID | 9708471
(Publication Type: Journal Article)
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Chemical References |
- Vasodilator Agents
- Nitroprusside
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Topics |
- Adult
- Aged
- Blood Pressure
(drug effects, physiology)
- Calcinosis
(complications)
- Cardiac Volume
(physiology)
- Cardiomyopathy, Dilated
(complications)
- Chronic Disease
- Echocardiography, Doppler, Color
- Endocarditis
(complications)
- Female
- Forecasting
- Heart Valve Diseases
(complications)
- Humans
- Infusions, Intravenous
- Male
- Middle Aged
- Mitral Valve
(diagnostic imaging, drug effects, physiopathology)
- Mitral Valve Insufficiency
(diagnostic imaging, etiology, physiopathology)
- Mitral Valve Prolapse
(complications)
- Myocardial Contraction
(physiology)
- Myocardial Ischemia
(complications)
- Nitroprusside
(administration & dosage)
- Rheumatic Heart Disease
(complications)
- Vasodilator Agents
(administration & dosage)
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