title: Functional evaluation of the bileaflet mechanical valve in the aortic position using dobutamine-stress echocardiography: is a 23-mm prosthetic valve adequately large enough?
abstract: The issue of valve prosthesis-patient mismatch in small annular patients is still controversial. The hemodynamic function of bileaflet mechanical valves in the aortic position was examined using dobutamine-stress echocardiography. Forty-four patients were enrolled in the study and divided into 5 groups, according to prosthesis size, from 21 mm to 29 mm. The aortic peak pressure gradient (APG) increased significantly in all groups with dobutamine-stress and exceeded 50 mmHg in 83% of the 21-mm group, in 64% of the 23-mm group, and in 33% of the 25-mm group. The APG even exceeded 80 mmHg in 22% and 18% of the 21-mm and 23-mm groups, respectively. In these cases, the potential of 'valve prosthesis-patient mismatch' was considered. From the relationship between the APG and the prosthesis valve area index (VAI), 'critical VAIs' were found where patients were likely to enter the 'mismatch' status; that is, 1.22 and 1.77 cm2/m2, respectively, for the 5 and 10 microg/kg per min stages of dobutamine stress. This critical VAI range is useful in predicting the 'mismatch' patients preoperatively. Alternative procedures or prostheses should then be selected for them.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Sapporo Medical University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tsukamoto
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Hachiro
authors.forename: S
authors.initials: S
authors.lastname: Muraki
authors.forename: T
authors.initials: T
authors.lastname: Abe
mesh_terms: D000328:Adult; D000368:Aged; D001021:Aortic Valve / Q000502:physiology* / Q000601:surgery*; D002302:Cardiac Output / Q000502:physiology; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006349:Heart Valve Diseases / Q000503:physiopathology / Q000601:surgery; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011312:Pressure; D011474:Prosthesis Design
chemical_list: D004280:Dobutamine