Doppler echocardiographic characteristics of normal and dysfunctioning prosthetic valves in the tricuspid and mitral position

Doppler Echocardiographic Evaluation of Prosthetic Valves in Tricuspid Position

Doppler echocardiographic characteristics of 29 normally functioning prosthetic valves (23 mechanical, 6 biological) and 8 obstructed mechanical prostheses in the tricuspid position are reported. In normally functioning prostheses, peak velocity, mean pressure gradient, and pressure-half time were 1.25 ± 0.18 m·sec−1, 2.6 ± 1.1 mm Hg, and 122.6 ± 30.7 msec, respectively. Although no significant differences were seen in peak velocity and mean pressure gradient between mechanical and biological valves, the pressure half-time was significantly greater in biological valves. All normally functioning prostheses had a mean pressure gradient ⩽5.5 mm Hg and pressure half-time < 200 msec. In obstructed bileaflet valves, peak velocity was 1.66 ± 0.28 m·sec−1, mean pressure gradient was 6.1 ± 2.8 mm Hg, and pressure half-time was 265.8 ± 171.7 msec. These Doppler data were significantly greater than those in normally functioning valves where the mean pressure gradient was ⩽5.1 mm Hg and the pressure half-time was ⩽156 msec in all except one patient. Pathological obstruction of a tricuspid prosthesis can be strongly suspected in patients with a mean pressure gradient > 5.5 mm Hg and a pressure half-time > 200 msec on Doppler echocardiography.

Effect of respiration on Doppler parameters of normal tricuspid porcine bioprosthetic valves

The Doppler indexes of tricuspid porcine bioprosthetic valves were evaluated in twelve patients without clinical and two-dimensional echocardiographic evidence of valve dysfunction. Peak and mean pressure gradients across the prostheses were measured using the simplified Bernoulli equation. All the Doppler measurements were compared during inspiration and expiration. During inspiration peak velocity, peak gradient and mean gradient (1.52 +/- 0.28 m/s; 9.7 +/- 3.05 mmHg; 4.07 +/- 1.16 mmHg) were significantly higher than during expiration (1.28 +/- 0.8 m/s; 6.58 +/- 2.7 mmHg; 2.98 +/- 1.13 mmHg; p < 0.01) but pressure half time was not significantly different (122 +/- 62 ms versus 134 +/- 75 ms; p > 0.05). Inspiratory range of peak velocities, peak gradients, mean gradients and pressure half times were respectively 0.8-2.04 m/s; 4.9-16.6 mmHg; 1.2-7.2 mmHg; 42-340 ms while expiratory range of values was 0.8-1.93 m/s; 2.6-15 mmHg; 1.1-5.7 mmHg; 46-345 ms. These data suggest that even very long pressure half times do not indicate valve dysfunction. This study demonstrates that large variation of Doppler parameters are present during respiration and could produce inaccuracy in the assessment of bioprostheses in tricuspid position if they are not taken in consideration.

Echocardiographic assessment of artificial heart valves: British Society of Echocardiography position paper

Images

Echocardiographic description of the CarboMedics bileaflet prosthetic heart valve

OBJECTIVES

The aim of this study was to describe the echocardiographic appearance of the normal CarboMedics prosthesis in the aortic and mitral positions.

BACKGROUND

Echocardiography is the standard method of assessing prosthetic valves. However, new valve designs may still be marketed without an accompanying echocardiographic description. The CarboMedics prosthesis is in widespread use, but few noninvasive hemodynamic data have been published.

METHODS

Echocardiography was performed in 147 patients with a total of 96 normally functioning CarboMedics prostheses in the aortic position and 75 in the mitral position; in 24 patients, valves were implanted in both positions. The following variables were measured: peak and mean transvalvular velocities, peak and mean instantaneous gradient estimated from the modified Bernoulli equation, aortic acceleration slope, pressure half-time, transvalvular flow and effective orifice area using the continuity equation. Patterns of regurgitation were observed by transthoracic study in all valves and by transesophageal study in selected mitral valve prostheses.

RESULTS

For the aortic valve prostheses, estimated mean gradient ranged between 6 and 19 mm Hg. Effective area differed markedly among the anulus diameters (p < 0.001), with a mean value of 1 cm2 for the 19-mm valve and 2.6 cm2 for the 29-mm valve. For the mitral valve prostheses, mean gradient ranged from 3 to 7 mm Hg. There were a total of four washing leaks, one on either side of each pivotal point, and these lasted throughout systole or diastole. One jet was commonly more prominent than the other three.

CONCLUSIONS

The CarboMedics prosthesis offered relatively little resistance to forward flow except at small anulus diameters. The washing jets were prominent and would be easy to misdiagnose as a sign of paraprosthetic regurgitation.

Color Doppler regurgitant characteristics of normal mechanical mitral valve prostheses in vitro

BACKGROUND

To evaluate normal regurgitant characteristics of St. Jude (SJ) and Medtronic-Hall (MH) mitral valves, four sizes (25-31 mm) of each were studied in a pulsatile flow model.

METHODS AND RESULTS

Regurgitant flow was measured by flowmeter at left ventricular pressures of 80, 130, and 180 mm Hg. Peak regurgitant flow rates ranged from 6.2 to 12.7 cm3/sec in SJ valves and from 7.9 to 17.5 cm3/sec in MH valves. Regurgitant orifice areas calculated from the Doppler continuity equation ranged from 1.6 to 2.0 mm2 in SJ valves and from 2.2 to 2.9 mm2 in MH valves. Regurgitant volumes across the closed valve at a left ventricular pressure of 130 mm Hg were normalized to an ejection time of 280 msec and ranged from 1.5 to 1.9 cm3 in SJ valves and from 2.1 to 2.8 cm3 in MH valves. Jets were imaged by color Doppler in six rotational planes, and jet size and morphology were compared with those of regurgitant jets from circular orifices with sizes comparable to the calculated prosthetic valve regurgitant orifices (1.1-3.1 mm2). SJ valves showed two converging jets from the pivot points, one central jet, and a variable number of peripheral jets. The mean color jet area derived from the six image planes ranged from 1.6 to 5.3 cm2. Aliasing occurred only close to the valve (maximal distance 0.5-2.0 cm). MH valves showed a large central jet with a maximal length of aliased flow between 2.0 and 5.5 cm. Depending on valve size, driving pressure, and image plane, one or two small peripheral jets were found. These jets did not show aliasing in any case. The mean color jet area ranged from 5.1 to 11.0 cm2. Jets originating from circular orifices of comparable size showed jet areas from 5.5 to 13.9 cm2 and aliasing distances from 3.3 to 7.3 cm. At similar regurgitant orifice areas, driving pressures, and regurgitant flows, the measured color areas and aliasing distances were smallest in SJ valves, larger in MH valves, and largest in simple circular orifices.

CONCLUSIONS

Large, complex regurgitant jets can be found in normal closed SJ and MH valves by color Doppler, although regurgitant flow volume is minimal. Jet size and velocity distribution differs markedly between SJ valves, MH valves, and circular orifices, even with comparable driving pressure, regurgitant orifice area, and regurgitant volume. The characteristic patterns of normal regurgitation must be recognized to avoid incorrect diagnoses of pathological regurgitation in SJ and MH prosthetic valves. MH valves should not be removed solely on the basis of a central regurgitant jet with a long aliasing distance. Peripheral jets in MH valves and all jets in SJ valves should be considered normal as long as no or only minimal aliasing is present. In contrast, peripheral jets with significant aliasing may represent strong evidence of pathological regurgitation.

Doppler echocardiographic evaluation of streptokinase lysis of thrombosed right-sided St. Jude Medical valves in patients with congenital heart defects

Four episodes of St. Jude Medical prosthesis leaflet thrombosis were serially evaluated by two-dimensional and Doppler echocardiography during treatment with streptokinase. Three patients aged 4, 11, and 24 years with congenital heart disease had St. Jude Medical valves in pulmonary positions (two cases) for tetralogy of Fallot and in the tricuspid position (one case). The duration of thrombosis was not known in any patient. Leaflet immobility and its resolution were demonstrated by echocardiography and were confirmed fluoroscopically. Continuous wave Doppler echocardiography showed abnormal stenotic gradients in thrombosed valves that were reduced after thrombolysis. These studies demonstrate the utility of two-dimensional and Doppler echocardiography in serial evaluation of prosthetic pulmonary and tricuspid valve thrombosis during thrombolysis.

Reference values and reproducibility of Doppler echocardiography in the assessment of the tricuspid valve and right ventricular diastolic function in normal subjects

The Doppler echocardiographic indexes of the tricuspid and mitral valves were assessed in 74 normal subjects (35 women and 39 men, mean age 45 years). A reproducibility study was also performed to examine the various sources of technical and biological variability. There were significantly higher peak early and late flow velocities across the mitral valve than across the tricuspid valve (0.67 +/- 0.13 and 0.47 +/- 0.12 vs 0.51 +/- 0.08 and 0.35 +/- 0.09 m.s-1, respectively; all p less than 0.0001). There was no significant difference between the early:late (E:A) velocity ratios of the 2 valves (1.65 +/- 0.73 vs 1.75 +/- 0.67, p less than 0.01). There was a steeper mitral early deceleration slope (-3.59 +/- 1.07 vs -2.95 +/- 0.91 m.s-2) but no significant difference in pressure half-times across the 2 valves (47 +/- 7 vs 51 +/- 12 ms, p less than 0.1). No influence of gender or body surface area could be demonstrated. There was a weak but significant relation between mitral peak early, peak atrial velocity and E:A ratio and age (r = -0.39, p less than 0.001, r = 0.23, p less than 0.01, and r = -0.245, p less than 0.01, respectively). There was no significant correlation between any of the tricuspid flow parameters and age. Respiration caused pronounced variability in the tricuspid Doppler indexes and all tricuspid flows were sampled and analyzed only during inspiration. The intra- and interobserver variabilities were small for all of the Doppler indexes measured, but the day-to-day variability was quite significant especially for the pressure half-time, deceleration and acceleration slope values.(ABSTRACT TRUNCATED AT 250 WORDS)