Analysis of Doppler-Obtained Velocity Curves in Functional Evaluation of Mechanical Prosthetic Valves in the Mitral and Aortic Positions

Nily Goldrath*, Ronit Zimes, Zvi Vered

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

A total of 145 patients with 160 mechanical prostheses of the Björk-Shiley or Starr-Edwards type (15 with double mitral plus aortic valves) underwent clinical and Doppler echocardiography analysis. In the mitral position (85 valves) 10 patients with valve-related symptoms, calculated prosthetic area ⩽1 cm2, or mean transprosthetic gradient > 10 mm Hg by Doppler echocardiography were predefined as abnormal. Seven patients had operations, and prosthetic obstruction was confirmed in all. All patients had higher pulmonary pressures (p < 0.001) before valve replacement. Clinical presentation was variable; however, all those with proved prosthetic thrombosis had a fulminant course and distinctive velocity curves on Doppler. In the 75 patients predefined as normal, calculated valve area (2.3 ± 0.6 cm2, mean ± SD, range 1.3 to 3.7 cm2) and mean gradient (4.9 ± 1.7 mm Hg, range 1.5 to 9.5 mm Hg) were widely spread and were independent of prosthetic size ⩾27 mm. Clinically 37 of 75 patients were moderately to severely limited. Mean gradient above 5 mm Hg was associated with a higher incidence of chronic atrial fibrillation (p < 0.05), significant tricuspid regurgitation, failure of the right side of the heart, and significant fiinctional limitation (p < 0.02 for all). In the aortic position (75 valves) peak gradients were 28.2 ± 15 mm Hg (8 to 80 mm Hg). Mean gradients were 18 ±.9.6 mm Hg (6.5 to 46.5 mm Hg). Averaged gradients derived from the average of peak and late systolic gradients were 22.4 ± 12.7 mm Hg (6 to 62 mm Hg). In all five abnormal patients (two with endocarditis and three with hemodynamic decompensation) but also in 18 of 70 clinically normal valves, peak gradients were ⩾36 mm Hg (ranges 36 to 65 mm Hg in both). Gradients were unrelated to symptoms or to the duration of the valve in situ (3 weeks to 20 years). Gradients correlated with prosthetic size (r = 0.57) and were higher (p < 0.001) across small (19 to 23 mm) versus large (25 to 31 min) valves. Regurgitation was present in 40% of the mural prostheses. It was detected in 32% of the mitral prostheses defined as normal and was estimated as mild in most. Aortic regurgitation was present in all five abnormal aortic prostheses, significant in four, and in, 26 of the valves (37%) defined as normal, significant in two. Thus a wide heterogeneity of transprosthetic flow is present in clinically normal mechanical prostheses. In the mitral position valve area ⩽1 cm2 or mean gradient > 10 mm Hg indicates prosthetic obstruction. In the normal range a mean gradient of > 5 mm Hg may indicate a more complicated clinical course. A significant portion of clinically normal aortic prostheses show elevated gradients. Aortic prosthetic dysfiinction is associated with substantial regurgitation and significantly elevated gradients. Mild mechanical prosthetic regurgitation is common and has little significance. Doppler echocardiography is a most valuable tool for the assessment of mechanical prostheses.

Original languageEnglish
Pages (from-to)211-225
Number of pages15
JournalJournal of the American Society of Echocardiography
Volume1
Issue number3
DOIs
StatePublished - 1988
Externally publishedYes

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