Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography
Details
Serval ID
serval:BIB_614307784C43
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography
Journal
Annals of Thoracic Surgery
ISSN
0003-4975 (Print)
Publication state
Published
Issued date
01/1996
Volume
61
Number
1
Pages
48-57
Notes
Comparative Study
Journal Article --- Old month value: Jan
Journal Article --- Old month value: Jan
Abstract
BACKGROUND. Pressure gradients calculated from echo-cardiography after aortic valve replacement are commonly much higher than would be expected from in vitro measurements. METHODS. The mean, peak-to-peak, and maximal gradients across bileaflet aortic prostheses (St. Jude Medical) were measured invasively in 52 patients at high and low heart rate, cardiac index, and stroke volume. One week after operation the gradients were calculated from a standard transthoracic echocardiogram (delta p = 4v2(2)). In a second study 3 to 12 months later, gradients were calculated using the standard, simplified Bernoulli equation, and with the equation considering subvalvular flow velocities (delta p = 4(v2(2-)v1(2)). Invasive and echocardiographic measurements were matched and compared. RESULTS. Invasively measured mean gradients for 21 to 29-mm valves ranged from 7.4 +/- 4.9 to 4.3 +/- 1.6 mm Hg at systolic flow rates from 11.3 +/- 0.7 to 16.2 +/- 1.8 L.min-1.m-2. Mean echocardiographic gradients were 15.1 +/- 4.5 to 7.5 +/- 2.2 mm Hg (p < 0.001) with the standard method, and 10.5 +/- 1.9 to 5.6 +/- 1.5 mm Hg when considering the subvalvular flow velocity (p < 0.001). CONCLUSIONS. Mean gradients across bileaflet prostheses are generally low, even in small valves and with high systolic flow. The correlation of the invasive in vivo with in vitro gradients is good. Standard echocardiography overestimates gradients across bileaflet heart valves and high gradients are not due to valve dysfunction. Gradients obtained by echocardiography considering the subvalvular flow velocity correlate better to invasively measured and in vitro gradients.
Keywords
Adult
Aged
Aortic Valve/*physiopathology/*ultrasonography
Aortic Valve Insufficiency/physiopathology/surgery
Aortic Valve Stenosis/physiopathology/surgery
Blood Flow Velocity
Blood Pressure
Cardiac Output
Catheterization
*Echocardiography, Doppler
Female
Heart Rate
*Heart Valve Prosthesis
Humans
Intraoperative Period
Male
Middle Aged
Pressure
Stroke Volume
Ventricular Pressure
Pubmed
Web of science
Create date
28/01/2008 11:32
Last modification date
20/08/2019 15:18