Introduction

Although echocardiography is the imaging modality of choice for cardiac heart valves, it still has significant limitations when imaging prosthetic cardiac valves. These limitations are significant with bioprosthetic valves and are particularly problematic with mechanical valves. The classic limitation is the inability to evaluate mitral regurgitation (MR) from the apical window in patients with mechanical prosthetic valves because of reverberation artifacts and acoustic shadowing. Many of these limitations, particularly while imaging the mitral valve (MV), are overcome by transesophageal imaging; direct imaging from the left atrial side of the valve eliminates these shadowing artifacts, which reside on the ventricular aspect of the valve (Figure 8-1; Video 8-1). Sparse data exist regarding the use of real-time three-dimensional transthoracic echocardiography (RT3DTTE) with prosthetic valves, although in a small series of four patients with endocarditis, vegetations and/or dehiscence not recognized by two-dimensional (2D) TTE were seen.¹ Evaluation of prosthetic valves by RT3D transesophageal echocardiography (TEE) has been extensively reviewed.^2,3 In one study, RT3DTEE has been shown to be particularly accurate for diagnosing all types of prosthetic valve pathology compared with direct surgical inspection.⁴ However, MV visualization, particularly valve leaflet visualization, was far superior to that of aortic or tricuspid valves. Also in this study, most of the valves were free of disease and, in fact, had recently been placed. Despite being a study of 87 patients, fewer than 40 had prosthetic valves, and the number who had metallic prosthetic valves is not clear from the report.

Figure 8-1 Two-dimensional mid-esophageal image of a mechanical double-tilting-disk mitral valve prosthesis captured in the closed position during systole. The image clearly illustrates the characteristic V pattern produced by the occluding disks.

A notable advantage of RT3DTEE compared with 2DTEE for all mechanical valves in the mitral position is the ability to visualize the entire valve in one full-volume or 3D zoom capture compared with visualization of only a single thin slice by 2D (Figures 8-1 to 8-6; Videos 8-1 to 8-6). Besides live 3D imaging, RT3DTEE has the ability to acquire a 3D volume that can then be cropped and rotated to reveal pathology such as leaflet immobility, thrombi or vegetations, dehiscence, or, with the addition of 3D color, even small perivalvular leaks (see Figure 8-4 and Video 8-4). Details of the valve, such as the sewing ring, the individual stitches, the struts, and the entire leaflet motion are well visualized by RT3DTEE (see Figure 8-6 and Video 8-6). Again, such visualization is much less frequently seen in valves in either the aortic or tricuspid position.

Figure 8-2 En face view of a mechanical double-tilting-disk mitral valve prosthesis captured in the open position during diastole. The image clearly illustrates the sewing ring and the two disks.

Figure 8-3 Two-dimensional echocardiographic image of a stented bioprosthetic valve in the mitral position.

Figure 8-4 Ventricular aspect of a stented bioprosthetic valve in the mitral position imaged with three-dimensional transesophageal echocardiography.

Figure 8-5 Two-dimensional mid-esophageal short-axis view of a 23-mm bioprosthetic aortic valve (PERIMOUNT Magna, Edwards Lifesciences, Irvine, CA) in the closed position. The image depicts the three stents at the commissural points.

Figure 8-6 Three-dimensional mid-esophageal en face view of a 23-mm bioprosthetic aortic valve (PERIMOUNT Magna, Edwards Lifesciences, Irvine, CA) in the closed position. The image depicts the three stents at the commissural points as well as the closure line of the three leaflets.

Abnormal Pathology with Mechanical Valves

Visualization of masses or the pannus on mechanical valves by RT3DTEE has not been rigorously studied because such problems are relatively uncommon. Only case reports exist of pannus formation on bileaflet mechanical valves in the mitral position evaluated by RT3DTEE, but in one published case, the pannus was identified by RT3DTEE and not seen at all by 2DTEE.⁵ Thrombus formation can be more precisely evaluated by RT3DTEE than by 2DTEE; in fact, this has confirmed our observation of the ability of RT3DTEE to appreciate that thrombi are larger and more numerous than thrombi detected by 2DTEE.^6,7

Guidance of Percutaneous Valve Placement

TEE is the standard for guiding percutaneous transcatheter aortic valve implantation. Data regarding the use of RT3DTEE for this particular procedure are limited, although it is routinely performed.¹⁰ Several potential advantages exist for RT3DTEE in this setting. The third dimension allows (1) more accurate assessment of the aortic annulus, the left ventricular outflow tract, and the aortic root size and shape; (2) measurement of the distance between the annulus and the left main coronary artery ostium; and 3) seating of the percutaneous valve while viewing the aortic valve en face and visualizing the valve leaflets and the tissue surrounding the prosthetic annulus.¹¹ This en face view is critically important for placement of the prosthetic valve to avoid postprocedure perivavluar regurgitation. RT3DTEE and biplane imaging also assist with the perioperative monitoring of all procedural aspects, including advancements of guidewires into the aortic valve and the placement of pigtail catheters in the sinus of Valsalva and the left ventricle, as well as balloon valvuloplasty or valve deployment. Ultimately, 2DTEE and RT3DTEE should be used as complementary imaging modalities to assess the satisfactory positioning and function of the implanted valve.

Reports of small series of transcatheter mitral valve-in-valve implantations have appeared in the literature. RT3DTEE has also been routinely used for this purpose.¹² Although this procedure is currently not available in the United States, RT3DTEE will be a mainstay for deployment of mitral valve-in-valve devices when they do become available.

Summary

In general terms, 2D and 3D imaging should be seen as complementary modalities. RT3D, especially RT3DTEE, significantly adds to the evaluation of both biologic and mechanical prostheses, especially in the MV position. The capabilities of real-time 3D acquisition—online rendering and cropping—permit accurate identification of the precise location and pathology associated with a prosthetic valve, guide corrective intervention, and will potentially help transition this modality into standard of care. One caveat exists, however; RT3DTEE is subject to the same physical laws of 2D ultrasound and is therefore prone to the same ultrasound artifacts.

Case Studies

Case 1 (Figures 8-7 and 8-8; Videos 8-7 and 8-8)

Bioprosthetic valve in the mitral position: The patient was admitted after a fall. TTE showed increased gradient across the MV. TEE and RT3DTEE showed two of the three leaflets of the valve to be immobile.

Figure 8-7 Three-dimensional transesophageal echocardiography of a bioprosthetic valve in the mitral position viewed from the left ventricular side. Note that two of the three leaflets are immobile (see Video 8-7).

Figure 8-8 Three-dimensional transesophageal echocardiography of a bioprosthetic valve in the mitral position viewed from the left atrial side. Note that two of the three leaflets are immobile (see Video 8-8).

Case 2 (Figures 8-9 to 8-13; Videos 8-9 to 8-12)

Prosthetic valve periprosthetic regurgitation: A bioprosthetic valve in the tricuspid position was placed because of endocarditis. After surgery, TEE was repeated because of suspicion of recurrent endocarditis. However, no vegetations or abscess cavities were appreciated, but periprosthetic regurgitation was found. This seemed to be an incidental finding because the patient had no clinical symptoms that could be the sequelae of the regurgitation.

Figure 8-9 Three-dimensional transesophageal echocardiography image showing periprosthetic regurgitation. This is a bioprosthetic valve in the tricuspid position, and the regurgitant jet is seen just adjacent to the sewing ring.

Figure 8-10 Two-dimensional transesophageal echocardiography of periprosthetic regurgitation adjacent to the sewing ring of a bioprosthetic valve in the tricuspid position (see Video 8-9).

Figure 8-11 Three-dimensional transesophageal echocardiography image of periprosthetic regurgitation adjacent to the sewing ring of a bioprosthetic valve in the tricuspid position (see Video 8-10).

Figure 8-12 Three-dimensional transesophageal echocardiography image of periprosthetic regurgitation adjacent to the sewing ring of a bioprosthetic valve in the tricuspid position (see Video 8-11).

Figure 8-13 Swivel view of the periprosthetic regurgitation adjacent to bioprosthetic valve in the tricuspid position (see Video 8-12).

Case 3 (Figures 8-14 to 8-21; Videos 8-13 to 8-16)

Left ventricular outflow tract mass: A bioprosthetic valve was present in the aortic position. TTE suggested a vegetation on the aortic valve. By TEE, a mass was seen prolapsing into the left ventricular outflow tract and was confirmed by RT3DTEE. Although endocarditis could not be excluded by TEE, it was believed to possibly represent primary valve failure. Subsequent cultures did not grow any organisms. Because of aortic regurgitation, the valve was subsequently replaced with another bioprosthetic valve.

Figure 8-14 Mass seen in the left ventricular outflow tract (see Video 8-13).

Figure 8-15 Severe aortic regurgitation.

Figure 8-16 A mass in the left ventricular outflow tract (see Video 8-14).

Figure 8-17 Two-dimensional transesophageal echocardiography of a mass in the left ventricular outflow tract (see Video 8-15).

Figure 8-18 Two-dimensional transesophageal echocardiography image of a mass prolapsing into the left ventricular outflow tract.

Figure 8-19 Two-dimensional transesophageal echocardiography showing severe aortic regurgitation (see Video 8-16).

Figure 8-20 Two-dimensional transesophageal echocardiography short-axis view of the aortic valve showing a mass in the left ventricular outflow tract.

Figure 8-21 Three-dimensional transesophageal echocardiography (3DTEE) of the mass in the left ventricular outflow tract (LVOT). In this case, the mass is appreciated in its entirety with 3DTEE and is a higher percentage of the LVOT compared with two-dimensional TEE.

Case 4 (Figures 8-22 and 8-23; Videos 8-17 and 8-18)

Thrombosis of St. Jude mitral valve: The patient had voluntarily stopped her oral anticoagulation (warfarin) for her prosthetic St. Jude MV. She was subsequently admitted for cerebrovascular accident and found to have a thrombus, thought to be embolic, in the left middle cerebral artery. TEE was performed and showed a thrombus in the left atrial appendage and a thrombus on the prosthetic MV. Visualization of the thrombus was more optimal with RT3DTEE than with 2DTEE. The size of the thrombus was measured by offline techniques; the diameter was noted to be larger with the use of RT3DTEE than with 2DTEE.

Figure 8-22 Two-dimensional transesophageal echocardiography image showing a thrombus associated with the bileaflet mitral valve (see Video 8-17).

Figure 8-23 Three-dimensional transesophageal echocardiography (TEE) image in the same patient in Figure 8-22. In this case, both the length and width of the thrombus are appreciated to be greater than was demonstrated by two-dimensional TEE (see Video 8-18).

Case 5 (Figures 8-24 to 8-30; Videos 8-19 to 8-22)

Vegetation on a prosthetic aortic valve: TEE was performed on this patient, who had blood cultures positive for Candida tropicalis. A vegetation was seen on the prosthetic St. Jude aortic valve.

Figure 8-24 Two-dimensional transthoracic echocardiography image of a mass, presumed to be a vegetation, seen in the left ventricular outflow tract in a patient with a bileaflet mechanical valve in the aortic position. Blood cultures were positive for Candida tropicalis.

Figure 8-25 Two-dimensional transesophageal echocardiography image showing a mass in the left ventricular outflow tract consistent with a vegetation. The patient’s blood cultures were positive for Candida tropicalis.

Figure 8-26 Three-dimensional transesophageal echocardiography image on the aortic side of the valve, where no mass is seen.

Figure 8-27 Three-dimensional transesophageal echocardiography image on the aortic side of the valve, where no mass is seen.

Figure 8-28 Three-dimensional transesophageal echocardiography on the aortic side of the valve, where no mass is seen.

Figure 8-29 Two-dimensional transthoracic echocardiogram of a mass, presumed to be a vegetation, seen in the left ventricular outflow tract in this patient with a bileaflet mechanical valve in the aortic position. Blood cultures were positive for Candida tropicalis.

Figure 8-30 Two-dimensional transesophageal echocardiography image showing a mass in the left ventricular outflow tract consistent with a vegetation. The patient’s blood cultures were positive for Candida tropicalis.

Case 6 (Figures 8-31 to 8-35; Videos 8-23 to 8-26)

Fungal endocarditis of a bioprosthetic valve in the mitral position: Six months after implantation of a porcine bioprosthetic valve in the mitral position and coronary artery bypass grafting, this 74-year-old female patient was admitted with fever, symptoms of acute heart failure, and multiple episodes of syncope. TEE revealed near-complete stenosis of her stented bioprosthesis due to massive fungal endocarditis (Exserohilum spp.).

Figure 8-31 Two-dimensional mid-esophageal zoomed transesophageal echocardiography image of a completely overgrown bioprosthetic valve in the mitral position. Massive fungal endocarditis has resulted in severe mitral valve stenosis with an effective orifice area of 0.3 cm² (see Video 8-23).

Figure 8-32 Three-dimensional transesophageal echocardiography en face view of the completely overgrown bioprosthetic valve in the mitral position shown in Figure 8-31. Note the severely stenosed mitral valve bioprosthesis with an effective orifice area of 0.3 cm² (see Video 8-24).

Figure 8-33 Three-dimensional transesophageal echocardiography color image of overgrown prosthetic valve indicates the extremely limited mitral valve orifice (see Video 8-25).

Figure 8-34 The completely overgrown bioprosthetic valve shown in Figure 8-31 as it was excised from the mitral position. Note that the fungal process has resulted in a near-complete obliteration of the bioprosthesis.

Figure 8-35 Postoperative three-dimensional (3D) en face image in the patient shown in Figure 8-31 obtained with live 3D acquisition demonstrating the replaced bioprosthesis in the mitral position (see Video 8-26).

Case 7 (Figures 8-36 and 8-37; Videos 8-27 to 8-29)

Thrombosis of a mechanical bileaflet tilting-disk valve with a stuck anterior disk in the mitral position: This young patient had neglected to take warfarin as prescribed and was admitted to the hospital in acute renal failure with symptoms of heart failure.

Figure 8-36 Mid-esophageal two-chamber view of the thrombosed mitral valve prosthesis with a stuck anterior leaflet (see Video 8-27).

Figure 8-37 Three-dimensional transesophageal echocardiography en face view of the thrombosed mitral valve prosthesis with a stuck anterior leaflet (see Video 8-28).

Case 8 (Figures 8-38 to 8-42; Videos 8-30 to 8-34)

A 64-year-old man who underwent coronary artery bypass grafting and St. Jude mitral valve replacement in 1998: The patient developed Streptococcus constellatus endocarditis and underwent repeat MV replacement in January 2008 with a CarboMedics (Sorin Group, Milan, Italy) mechanical valve. After that surgery, the patient never regained his previous state of health and had progressive loss of strength as well as increasing shortness of breath at rest and with mild activity. He was ultimately found to have persistent anemia; blood cultures were positive for methicillin-resistant Staphylococcus epidermidis on four occasions, and he was placed on appropriate antibiotics. TTE showed severe MR and a rocking MV prosthesis. Intraoperative TEE confirmed anterior dehiscence of the mechanical bileaflet tilting-disk valve in the mitral position along with rocking motion. The extent and location of the dehiscence are easily appreciated on the RT3DTEE en face view, but the mid-esophageal, two-chamber view with the multiplane angle at 90 degrees does not reveal the dehiscence.

Figure 8-38 Zoomed two-dimensional transesophageal echocardiography image of an anteriorly dehisced bileaflet tilting-disk prosthesis in the mitral position. The asterisk indicates the dehiscence (see video 8-30).

Figure 8-39 Zoomed two-dimensional transesophageal echocardiography image demonstrating the significant regurgitant jet anterior of the dehisced bileaflet tilting-disk prosthesis in the mitral position (see Video 8-31).

Figure 8-40 Two-dimensional transesophageal echocardiography two-chamber view of the same dehisced tilting-disk prosthesis in the mitral position shown in Figure 8-39. Note that the dehiscence is not necessarily being detected at this orientation of the multiplane angle (i.e., 96 degrees). However, the moving image demonstrates the rocking motion of the mechanical valve (see Video 8-32).

Figure 8-41 Zoomed real-time three-dimensional transesophageal echocardiography en face image of the anteriorly dehisced tilting-disk prosthesis shown in Figure 8-39. Note that the dehiscence extends at the entire anterior aspect of the valve (arrows) (see Video 8-33). AV, aortic valve.

Figure 8-42 Three-dimensional color transesophageal echocardiographic image illustrates the enormous extent of the dehiscence of the mechanical valve shown in Figure 8-39 from the anterior aspect of the mitral valve annulus (see Video 8-34).