Doppler echocardiographic appearance of cusp tears in tissue valve prosthesis

Natural history of early aortic paraprosthetic regurgitation: a five-year follow-up

OBJECTIVES

To assess the incidence and natural course of paravalvular leaks detected early after aortic valve replacement.

BACKGROUND

Although the use of echocardiography has simplified the postoperative assessment of patients with aortic valve replacement, there are no data regarding the natural history of early detected paravalvular aortic leaks.

METHODS

Eighty-four consecutive patients with aortic valve replacement were prospectively followed clinically every 6 months and by echocardiography early (11 +/- 7 days), at midterm (27 +/- 3 months), and late (63 +/- 4 months) after aortic valve replacement. The competence of artificial valves was assessed by Doppler color flow mapping.

RESULTS

Paraprosthetic leaks were detected in 40 (47.6%) aortic prostheses during the early study; the majority (90%) were small. All leaks remained unchanged during the follow-up period. Left ventricular dimensions and function did not differ between patients with or without paravalvular leak during the follow-up. Left ventricular fractional shortening, however, increased during the intermediate study in both subgroups, indicating improved left ventricular function overall. Three patients had severe paravalvular regurgitation suddenly develop from late infective endocarditis, and 1 patient had a degenerative tissue valve failure 4 years after implantation.

CONCLUSIONS

Paraprosthetic aortic leaks detected early after surgery, in the absence of valve infection, are common, are usually small, and have a benign course. However, the development of new, usually severe, regurgitation should raise the suspicion of prosthetic valve endocarditis or bioprosthetic valve failure.

The vibratory innocent heart murmur in schoolchildren: a case-control Doppler echocardiographic study

In 810 schoolchildren (aged 5-14 years) the prevalence of a grade 1-3/6 vibratory innocent heart murmur (VIHM) is 41%. Restricted to a grade 2 or 3 VIHM, the prevalence is 14%, decreasing from 21% in the age-class 5-6 years to 8% for children 13-14 years of age. The prevalence of a grade 3 VIHM is 1%. Together with a matched control, 84 children with a grade 2 or 3 VIHM underwent further cardiologic examination including electrocardiography, phonocardiography, and Doppler echocardiography. A positive correlation was found between the presence of a VIHM and higher left ventricular voltages on the ECG, but within the normal range; lower heart rate; smaller diameter of the ascending aorta (AAO); and higher blood flow velocity and higher maximal acceleration of the blood flow in the LVOT and the AAO. In 40% of the children with a VIHM, a systolic aortic valve vibration was seen with a frequency > or = 100 Hz and an amplitude > or = 1 mm, whereas this type of vibration was present in only one case control. No significant difference was found concerning the prevalence of false tendons in the left ventricle, systolic and diastolic diameter of the left ventricle, systolic time intervals, and shortening fraction of the left ventricle. The VIHM is strongly associated with a smaller AAO, with higher velocity and acceleration of the blood flow in the LVOT and AAO, and with a vibratory phenomenon of the aortic valve, pointing towards the LVOT-aortic valve region as the site of origin of the VIHM.

Comparison of transthoracic and transesophageal echocardiography for detection of abnormalities of prosthetic and bioprosthetic valves in the mitral and aortic positions

Two-dimensional echocardiography is the diagnostic procedure of choice for evaluation of prosthetic valve abnormalities. However, transthoracic echocardiography (TTE) may be limited owing to acoustic shadowing and poor acoustic windows. Some of these limitations may be overcome by transesophageal echocardiography (TEE). One hundred twenty-six patients with 148 prosthetic valves (113 bioprostheses and 35 mechanical devices) were studied by M-mode and 2-dimensional TTE and TEE. Prosthetic valve morphology was confirmed by surgery or autopsy in all cases; 124 prostheses were classified as diseased (33 endocarditis, 8 thrombi, and 83 degeneration defined as leaflet thickening > 3 mm with restricted motion) and 24 as normal. Prosthetic valve endocarditis and thrombi were correctly identified by TTE in 12 of 33 (36%) and 1 of 8 (13%) prostheses, respectively, but could be diagnosed by TEE in 27 of 33 (82%; p < 0.001) and 8 of 8 (100%; p < 0.01), respectively. Compared with TTE, TEE had a higher sensitivity for morphologic prosthetic valve abnormalities in patients with either bioprostheses (88 [87%] vs 66 [65%] of 101 prostheses; p < 0.01) or mechanical devices (19 [83%] vs 5 [22%] of 23 prostheses; p < 0.01) and in patients with a prosthesis in either the aortic (49 [77%] vs 32 [50%] of 64; p < 0.01) or mitral (58 [97%] vs 39 [65%] of 60; p < 0.001) position. Overall, sensitivity and specificity were 57 and 63%, respectively, for TTE, and 86 and 88%, respectively, for TEE.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of acceleration flow signals proximal to the leaking orifice in assessing the severity of prosthetic mitral valve regurgitation

To test the value of acceleration flow signals proximal to the leaking orifice in assessing the severity of prosthetic mitral valve regurgitation, 39 consecutive patients undergoing left ventriculography were examined by Doppler color flow imaging. Acceleration flow signals proximal to the regurgitant orifice were detected in 27 of the 31 patients who had prosthetic mitral regurgitation by left ventriculography (sensitivity 87%). All four patients without acceleration flow signals had mild prosthetic mitral regurgitation by angiography. No acceleration flow signals were detected in any patient without prosthetic regurgitation by left ventriculography (specificity 100%). Individual values of the maximal area of acceleration flow signals obtained from three orthogonal planes in seven patients with mild prosthetic mitral regurgitation by angiography ranged from 0 to 17 mm2 (mean 4 +/- 6). In 8 patients with moderate prosthetic mitral regurgitation by angiography, the maximal area of acceleration flow signals ranged from 21 to 58 mm2 (mean 33 +/- 15), whereas the maximal area of acceleration flow signals in 16 patients with severe prosthetic regurgitation ranged from 20 to 173 mm2 (mean 102 +/- 41). The maximal area of the acceleration flow signals from three planes correlated well with the angiographic grade of prosthetic mitral regurgitation. There was a significant difference in the maximal area of acceleration flow signals between mild and moderate (p less than 0.001), moderate and severe (p less than 0.001) and mild and severe (p less than 0.001) prosthetic mitral regurgitation. Thus, measurement of acceleration flow signals by Doppler color flow imaging is useful in assessing the severity of prosthetic mitral regurgitation.

Doppler and echocardiographic characteristics of patients having an Austin Flint murmur

BACKGROUND

The purpose of this study was to investigate the genesis of the Austin Flint murmur using Doppler and echocardiographic imaging.

METHODS AND RESULTS

A total of 51 patients having significant aortic insufficiency and an anatomically normal mitral valve were evaluated. They were divided into two groups; 30 patients had an audible Austin Flint murmur (AFM+) and 21 did not (AFM-). All patients had a complete M-mode, two-dimensional, and Doppler echocardiographic examination to characterize left ventricular size and function, motion of the mitral valve, transmitral flow velocities, direction of the aortic insufficiency jet, and severity of aortic insufficiency. There was no significant difference in severity of aortic insufficiency between groups. There was, however, a significant difference in direction of the insufficiency jet. In the AFM+ group compared with the AFM- group, for the parasternal long-axis view 24 (80%) versus eight (38%) had their insufficiency jet directed at the mitral valve, for the apical five-chamber view the values were 25 (83%) versus five (24%), and for the apical long-axis view the values were 27 (90%) versus five (24%); for all comparisons p less than 0.01. There was also a greater frequency of localized anterior mitral leaflet distortion by two-dimensional echocardiography (AFM+:23 [77%] versus AFM-:five [24%]; p less than 0.001) and a greater frequency of Doppler striations overlying the aortic insufficiency jet (AFM+:25 [83%] versus AFM-:seven [33%]; p less than 0.001). Regarding transmitral flow velocities, there was no significant difference in filling patterns or absolute velocities during early or late diastole between groups. There was no gradient by Doppler analysis or by hemodynamics (n = 26) across the mitral valve in either group. There also was no difference in the frequency of preclosure of the mitral valve (AFM+:two versus AFM-:three). Systolic function was similar in both groups, but the left ventricular end-diastolic dimension was significantly greater in the AFM+ group (6.8 +/- 0.8 cm) than in the AFM- group (6.2 +/- 0.7 cm, p = 0.008).

CONCLUSIONS

The results of this study suggest that the primary factor responsible for the Austin Flint murmur is the presence of an aortic insufficiency jet directed at the anterior mitral leaflet. This, combined with the biphasic pattern of transmitral flow, distorts the shape of the anterior mitral leaflet as it opens and closes during diastole, making it shudder. The leaflet's shuddering sets up vibrations and shock waves that distort the aortic insufficiency jet, causing the observed Doppler striations and probably the sound of the murmur. There is no evidence from this study to support prior theories that have proposed functional mitral stenosis or diastolic mitral regurgitation as the source of the murmur.

Patients' observations of bioprosthetic valve failure: "my heart is honking, doctor"

Audible cardiac murmurs are uncommon and may indicate severe native valve dysfunction. In six patients with bioprosthetic mitral valves audible honking systolic murmurs suddenly developed. Doppler echocardiography showed characteristic striated regurgitant signals. At operation each prosthesis had torn cusps. New audible murmurs and striated Doppler signals originating from mitral bioprosthetic valves are indicators of cusp tears. Recognition of this is important because early detection of prosthetic valve dysfunction may improve subsequent surgical outcome.

Doppler echocardiography assessment of prosthetic heart valves

Transthoracic Doppler echocardiography is an accurate noninvasive method for the evaluation of prosthetic valve function. The flow characteristics and pressure gradients of normally functioning mechanical and bioprosthetic valves have been, in general established. Normal functioning mitral valve prostheses have a valve area greater than 1.8 cm 2 with the St. Jude valve having the largest effective valve area and normally functioning aortic prosthetic valves have a peak instantaneous gradient of less than 45 mmHg, with the Starr-Edwards valves (Starr-Edwards, Irvine CA) showing the highest gradients. The incidence of minimal or mild regurgitation is approximately 15% to 30% in the mitral position and 25% to 50% in the aortic position, with the higher incidence of regurgitation seen with mechanical compared to bioprosthetic valves. Transthoracic Doppler echocardiography can accurately detect patients with prosthetic valvular stenosis. The presence of prosthetic aortic regurgitation can also generally be accurately assessed, except in the presence of both prosthetic aortic and mitral valves. Assessment of prosthetic mitral regurgitation remains limited due to significant attenuation of the ultrasound beam by the prosthesis and the frequent underestimation of severity of regurgitation. Other limitations of transthoracic studies include assessment of leaflet morphology, detection of vegetations and valve abscesses, and differentiation between valvular and paravalvular regurgitation.

Colour flow Doppler mapping in the assessment of prosthetic valve regurgitation

Two hundred Carpentier-Edwards, Björk-Shiley, and Starr-Edwards prostheses in 173 patients were examined. Sixteen (16%) in the aortic and 24 (25%) in the mitral position were associated with clinical signs of regurgitation. A phased array system (Hewlett-Packard A77020A) with a 2.5 MHz duplex and 1.9 MHz continuous wave transducer was used. Colour flow mapping showed trivial transvalvar regurgitation in 23 (53%) metal aortic prosthesis, and only nine (20%) metal mitral prostheses. This difference was probably attributable to shielding of the left atrium by the metal components. Colour mapping confirmed abnormal regurgitation in all aortic prostheses with early diastolic numbers, but regurgitation was also shown in 25 (29%) with no diastolic murmur. Abnormal mitral regurgitation was found in 13 (54%) patients with a pansystolic murmur, but also in six (8%) with no systolic murmur. Two patients, thought on clinical grounds to have mild mitral regurgitation, had unexpectedly large jets on colour flow mapping. About one in three prostheses had paraprosthetic leaks, 65 (79%) of which were small with a jet area less than 20% of the area of the receiving chamber. The development of new paraprosthetic leaks led to the diagnosis of bacterial endocarditis in two patients. In eight patients regurgitation was first diagnosed with continuous wave Doppler, but was afterwards shown with colour mapping and in a further 10 regurgitation could only be shown by continuous wave Doppler. Colour flow mapping was less sensitive than continuous wave Doppler in detecting regurgitation,but seemed able to distinguish normal transvalvar from paraprosthetic regurgitation. Further studies in the natural course of paraprosthetic leaks and a comparison of the transoesophageal and transthoracic approaches in the assessment of mitral prostheses are needed.

Doppler study of precordial musical murmurs

Using phonocardiography, continuous- and pulsed-wave Doppler, 51 patients with precordial "musical" murmurs (49 with cardiac abnormalities) and 21 patients with noisy murmurs were examined. With M-mode echocardiography, fine fluttering of the structure generating the murmur was evident in 23 patients with musical murmurs and in 5 with noisy murmurs. A continuous-wave Doppler spectral signal characterized by parallel harmonics (Doppler musical signal) was evident in all patients with musical murmurs and in none with a noisy murmur. With pulsed-wave Doppler, the musical signal had less defined spectral features because of range ambiguity. Such a signal was experimentally reproduced by activating a diapason bathed in saline solution. The source of the musical murmur was established in all 51 patients by Doppler. The musical signal was associated with a valvular regurgitation signal in 36 patients and with a ventricular septal defect in 1 patient. The musical signal always disappeared when the pulsed-wave Doppler sample volume was placed 2 cm away from the generating structure. In 11 patients with musical murmur examined by color Doppler, no abnormal bidirectional flow signal was observed in the structures generating the signal. In 6 of the patients without valvular regurgitation, no flow disturbance was found. In conclusion, Doppler is valuable in determining the source of musical murmurs, and musical murmurs are caused by a vibrating structure even in the absence of flow turbulence.

Reliability of M-mode, two-dimensional and Doppler echocardiography in diagnosing a flail mitral valve leaflet

The purpose of this study was to evaluate the M-mode, two-dimensional, and Doppler echocardiographic signs for a flail mitral valve leaflet. This was a retrospective evaluation of 54 patients who had (1) significant mitral regurgitation, (2) a technically adequate echocardiographic study, and (3) description of valve anatomy done at surgery or necropsy. The following M-mode signs were examined for their ability to detect a flail valve: (1) systolic flutter of the mitral valve closure line, sensitivity 29%, specificity 76%; (2) abnormal diastolic posterior leaflet motion, sensitivity 73%, specificity 71%; (3) abnormal diastolic anterior leaflet motion, sensitivity 67%, specificity 86%; (4) systolic atrial echoes, sensitivity 28%, specificity 68%; (5) multiple independent systolic closure lines, sensitivity 71%, specificity 52%. The two-dimensional echocardiographic signs evaluated were (1) diastolic inversion of the anterior leaflet toward the left atrium, sensitivity 29%, specificity 96%; (2) diastolic inversion of the posterior leaflet toward the left atrium, sensitivity 54%, specificity 93%, (3) systolic inversion of the anterior leaflet into the left atrium, sensitivity 57%, specificity 93%; (4) systolic inversion of the posterior leaflet into the left atrium, sensitivity 79%, specificity 86%; (5) systolic whipping of the mitral leaflets, sensitivity 73%, specificity 74%; (6) presence of floating apical chordae, sensitivity 30%, specificity 91%. Doppler echocardiographic signs evaluated were (1) presence of left atrial systolic antegrade flow, sensitivity 30%, specificity 91%; (2) vertical striations superimposed on the typical regurgitant flow pattern, sensitivity 75%, specificity 69%. When all the two-dimensional signs except systolic whipping and the M-mode signs for abnormal diastolic leaflet motion were combined, the sensitivity for detecting a flail mitral valve was maximized at 97%, but specificity was reduced to 64%. In conclusion, two-dimensional echocardiographic signs are more sensitive and specific than either M-mode or Doppler signs for detecting a flail mitral valve. The various M-mode, two-dimensional, and Doppler echocardiographic signs, however, are complementary to each other, and sensitivity is maximized when they are combined.