Transcatheter valve therapies





Transcatheter aortic valve replacement


Since the first transcatheter bioprosthetic aortic valve was implanted, changes have included smaller and more flexible delivery systems for use in smaller vessels; lower frame height in order to minimize interference with coronary blood flow, mitral valve function, and atrioventricular heart block; a basal skirt to minimize paravalvular regurgitation; and greater variety of valve sizes to accommodate different annular dimensions. Figs 13.8 , 13.20 , and 13.21 show the designs in common use today.



Fig 13.1


Normal anatomy of aortic annulus. The aortic leaflets insert into aorta in crown-like fashion (red, blue, and yellow), with high point being sinotubular junction. For purposes of annular sizing, the aortic annulus is defined as a virtual ring (green line) with three anatomical anchor points at nadir (green points) of each of the attachments of the three aortic leaflets.

(From Kasel AM, Cassese S, Bleiziffer S, et al: Standardized imaging for aortic annular sizing: Implications for transcatheter valve selection, JACC Cardiovasc Imaging 6:249–262, 2013. With permission.)



Fig 13.2


A common error that occurs with 2D estimation of aortic annulus is illustrated. Leaflet hinge points seen on 2D midesophageal long-axis image (left) represent the interface of the leaflet and left ventricular wall at either nadir of leaflet or basal plane (red line) or at a point (white circle, purple line) that is a highly variable distance (z) above the basal plane. Use of 3D TEE reconstructive techniques obviates the issue.

(From Jilaihawi H, Kashif M, Fontana G, et al: Cross-sectional computed tomographic assessment improves accuracy of aortic annular sizing for transcatheter aortic valve replacement and reduces incidence of paravalvular aortic regurgitation, JACC 59:1275–1286, 2012.)




CASE 13-1


Balloon expandable bioprosthetic aortic valve


This 82-year-old man with a history of remote CABG for coronary artery disease, type 2 diabetes, and severe COPD, had a 6-month history of progressive dyspnea on exertion, lightheadedness, and substernal chest pain. On TTE he was found to have severe aortic stenosis. Because of his high surgical risk and comorbidities, he was scheduled for transcatheter aortic valve replacement (TAVR).



Fig 13.3


Midesophageal long-axis view shows a heavily calcified aortic valve with mild aortic regurgitation (arrow). Video images show limited leaflet motion without color Doppler flow acceleration proximal to the valve. LV systolic function was normal, and there was only mild, central mitral regurgitation.



Fig 13.4


3D TEE from aortic side of the valve shows heavily calcified leaflets with a small systolic orifice area.



Fig 13.5


Deep transgastric image demonstrates the small jet of central aortic regurgitation. In cases of echo dropout from the esophageal window, gastric views offer an alternative.



Fig 13.6


Using the continuity equation, the aortic valve area is calculated at 0.7 cm 2 .



Fig 13.7


The top images show the use of multiplanar reconstruction (left) in deriving the cross-sectional diameters and area of the left ventricular outflow tract, which are consistent with those obtained by CT scan (right) . The bottom images show the use of multiplanar reconstruction (left) to derive the distance of the left main coronary ostium from the aortic annulus. This distance is consistent with those obtained by CT scan (right) . The risk of coronary artery occlusion by the native leaflets following valvuloplasty is higher with smaller coronary ostia-aortic annular distances. These measurements are made predeployment in an attempt to prevent either the frame of the implanted valve or the native coronary leaflet from extending to the upper margin of the coronary ostium.



Fig 13.8


(Left) The Edwards SAPIEN transcatheter heart valve. (Middle) The Edwards SAPIEN XT transcatheter heart valve. (Right) The Edwards SAPIEN 3 transcatheter heart valve; this newest iteration has a basal skirt designed to minimize paravalvular regurgitation.

Courtesy of Edwards Lifesciences LLC, Irvine, CA.







Fig 13.9


In another patient also having a TAVR, three components of deployment are seen. In the left two frames, balloon commissurotomy is performed; in the right two frames, the crimped valve is positioned 2–3 mm past the hinge point of the aortic and mitral valves and then deployed. Rapid ventricular pacing is used during balloon inflation.



Fig 13.10


Subsequent images are from the original patient. With fluoroscopy, the crimped valve is seen in position (left). In center, the balloon and valve have been expanded, and on right, the balloon has been deflated, leaving the valve in situ.



Fig 13.11


Midesophageal short-axis imaging shows the valve to be in good position, with no evidence of aortic regurgitation seen on color Doppler.



Fig 13.12


Midesophageal long-axis imaging also shows valve to be in good position, with no evidence of aortic regurgitation. There was no impingement of the valve on the anterior mitral leaflet nor was there worsening of preprocedural mitral regurgitation.



Fig 13.13


3D long axis shows the valve in the appropriate position.



Fig 13.14


Valve is seen in 3D from the left ventricular outflow tract perspective. There is no evidence of aortic regurgitation. Postdeployment gradients across the new valve were dramatically reduced. There was no change in the mild amount of mitral regurgitation after deployment of valve.




CASE 13-2


Transapical balloon expandable bioprosthetic aortic valve replacement


This 76-year-old man presented with increasing dyspnea and fatigue over a 6-month period. Severe aortic stenosis with an aortic valve area of 0.6 cm 2 was diagnosed by TTE. The patient had comorbidities that included severe PVD with iliac stents, as well as a previous CABG with patent LIMA graft.



Fig 13.15


In patients in whom lower extremity arteries are unable to accommodate the delivery system, a small thoracotomy may be performed to facilitate delivery through left ventricular apex. In this biplane image, a deep transgastric image is seen on left and orthogonal view on right. A guide wire (red arrow) has been introduced into left ventricle via apex, and has been advanced through LVOT and aortic valve.



Fig 13.16


As visualized with fluoroscopy, the delivery apparatus has been introduced into left ventricle via apex (left) and valve deployed (right).



Fig 13.17


In midesophageal short axis, deployed valve shows only mild paravalvular regurgitation (arrow).



Fig 13.18


In midesophageal long axis, deployed valve shows only mild paravalvular regurgitation (arrow). Valve is slightly more ventricular than desired, without any significant effect on mitral valve function.



Fig 13.19


Aortic valvar complex, including aortic valve, annulus, sinuses, aorta, coronary arteries, membranous septum, and mitral valve. Dotted red line indicates insertion of aortic leaflets, from basal ring to sinotubular junction. The proximity of the atrioventricular bundle (AVB) explains why heart block is more common with prostheses that extend further into left ventricle.

(From Leon MB, Piazza N, Nikolsky E, et al: Standardized endpoint definitions for transcatheter aortic valve implantation clinical trials: A consensus report from the Valve Academic Research Consortium, Eur Heart J 32:205–217, 2011. With permission.)




CASE 13-3


Self-expanding bioprosthetic aortic valve


The patient is an 85-year-old man with severe symptomatic aortic stenosis and multiple comorbidities. TAVR was recommended as treatment.



Fig 13.20A


Medtronic CoreValve (Medtronic, Minneapolis, Minnesota), top view. Trileaflet porcine valve is sewn into nitinol wire frame.



Fig 13.20B


Medtronic CoreValve (Medtronic, Minneapolis, Minnesota), side view.



Fig 13.21


Medtronic CoreValve positioned in aortic root.



Fig 13.22


Biplane imaging of deployed valve is seen in this midesophageal long-axis view. White arrow indicates the valve itself, which is above the annulus, which is indicated by the red arrow. Green arrow shows the ventricular portion of the frame abutting the interventricular septum.



Fig 13.23


Color Doppler imaging shows a jet of paravalvular regurgitation (white arrow).



Fig 13.24


3D TEE with color Doppler. Left frame is from left atrial perspective, and center frame is from left ventricular perspective. White arrow indicates anterior paravalvular jet, which is between the anterior mitral leaflet and the prosthetic valve. In right frame, three leaflets of the CoreValve are seen.



Fig 13.25


This series of fluoroscopic images shows the stages of valve deployment. In (A), the undeployed valve has been positioned across the native aortic valve. In (B) valve is allowed to expand from the ventricular side, and this process is carried on in (C). In (D), valve is completely deployed. Subsequent angiography showed coronary circulation to be normal.



Fig 13.26


Following deployment, the patient developed a new left bundle branch block, which resolved in 24 h.




Comments


Transcatheter aortic valve replacement (TAVR) is now a standard approach to treatment of adults with severe symptomatic aortic stenosis (AS) who have a high or prohibitive risk for surgical valve replacement. Echocardiography is essential for determining that AS is severe and for evaluation of ventricular size and function and other concurrent cardiac conditions before the procedure. Currently, transesophageal echocardiography (TEE) often is used during the procedure to assist in valve positioning and for rapid detection of complications after the procedure, as in these examples. In some cases, 3D TEE imaging of the LV outflow tract and aortic annulus may be helpful for valve sizing; however, CT imaging before the procedure is recommended for optimal valve sizing. TEE is feasible when general anesthesia is used for the TAVR procedure. As experienced centers transition to moderate sedation for TAVR procedures, transthoracic imaging may replace intraprocedural TEE with fluoroscopy used to guide placement of the prosthetic valve.


Suggested reading




  • 1.

    Hahn RT, Little SH, Monaghan MJ, et al: Recommendations for comprehensive intraprocedural echocardiographic imaging during TAVR, JACC Cardiovasc Imaging 8(3):261–287, 2015.


  • 2.

    Patel PA, Gutsche JT, Vernick WJ, et al: The functional aortic annulus in the 3D era: Focus on transcatheter aortic valve replacement for the perioperative echocardiographer, J Cardiothorac Vasc Anesth 29(1):240–255, 2015.


  • 3.

    Wang H, Hanna JM, Ganapathi A, et al: Comparison of aortic annulus size by transesophageal echocardiography and computed tomography angiography with direct surgical measurement, Am J Cardiol 115(11):1568–1573, 2015.



CASE 13-4


Paravalvular regurgitation after TAVR deployment


The patient is a 64-year-old man who over the previous 2 years had become increasingly short of breath, with frequent syncope. He was diagnosed with severe aortic stenosis. Because of hepatic cirrhosis, he was offered TAVR.



Fig 13.27


Mechanisms of para-prosthetic aortic regurgitation. After transcatheter aortic valve implantation, paravalvular leaks can result from underexpansion of prosthesis stent frame, which might be caused by calcifications of the annulus or cusps of the native valve (A), valve malposition with too shallow (B) or too deep (C) implantation depth of the prosthesis, and/or annulus-prosthesis size mismatch (D) .

(From Sinning JM, Hammerstingl C, Vasa-Nicotera M, et al: Aortic regurgitation index defines severity of peri-prosthetic regurgitation and predicts outcome in patients after transcatheter aortic valve implantation, JACC 59:1134–1141, 2012. With permission.)



Fig 13.28


Preoperative midesophageal long-axis imaging showed a heavily calcified aortic valve.



Fig 13.29


Using multiplanar reconstruction, the top two images showed a heavily calcified valve at the level of the leaflet bodies, whereas the bottom two images show less calcification at the leaflet edges.



Fig 13.30


3D TEE from the aortic perspective shows heavy calcification, with most of remaining leaflet tissue shadowed.



Fig 13.31


Using multiplanar reconstruction, diameter and area measurements were made. Corresponding CT measurements at right. Currently, CT measurements are recommended for clinical decision making about the type and size of TAVR valve.



Fig 13.32


In left panel is a midesophageal long-axis view with CD, showing paravalvular regurgitant jet. Middle panel is a zoomed image with the jet width measured at 0.48 cm. On right, the jet in short axis is seen. Location is posterior, and hugs anterior mitral leaflet. Quantification is difficult because the true vena contract is not evident. The jet width suggests a moderate degree of paravalvular regurgitation.



Fig 13.33


Pulsed Doppler of descending aorta does not show diastolic flow reversal. Arrows indicate QRS with systolic flow signal seen below zero baseline.




Suggested reading




  • 1.

    Abdelghani M, Soliman OI, Schultz C, et al: Adjudicating paravalvular leaks of transcatheter aortic valves: A critical appraisal, Eur Heart J 2016 Apr 13.


  • 2.

    Oh JK, Little SH, Abdelmoneim SS, et al: CoreValve U.S. Pivotal Trial Clinical Investigators: Regression of paravalvular aortic regurgitation and remodeling of self-expanding transcatheter aortic valve: An observation from the CoreValve U.S. Pivotal Trial, JACC Cardiovasc Imaging 8(12):1364–1875, 2015.


  • 3.

    Pibarot P, Hahn RT, Weissman NJ, et al: Assessment of Paravalvular Regurgitation Following TAVRA Proposal of Unifying Grading Scheme. JACC Cardiovasc Imaging 8(3): 340–360, 2015.



CASE 13-5


Transcatheter bioprosthetic valve prolapse


This 78-year-old man with symptomatic aortic stenosis presented with multiple comorbidities, including three previous sternotomies for coronary artery disease. He was offered TAVR as an alternative to sternotomy and surgical aortic valve replacement.



Fig 13.34


In this midesophageal long-axis view, there is obvious calcification of aortic leaflets.



Fig 13.35


Balloon commissurotomy was performed and the balloon expandable valve was deployed. It appeared to be in good position. White arrows indicate the valve frame.



Fig 13.36


Within seconds, the prosthetic valve had prolapsed back into the LVOT, and was now completely covering the anterior mitral leaflet. Red arrow indicates the new leaflets. Although there was no interference with mitral valve function, the native, stenotic valve is now evident. With color Doppler, aortic regurgitation is now seen, probably worsened by balloon commissurotomy.



Fig 13.37


Angiography shows the new valve (red arrow) to be well below the aortic sinuses (white arrow).



Fig 13.38


Following an attempt at pulling the first balloon expandable valve back with inflated balloon, a second balloon expandable valve is introduced through the first.



Fig 13.39


Following deployment of second valve, there was less contact with anterior mitral leaflet (left) . White arrow indicates the coaptation point of mitral leaflets. On right, the red arrow indicates the first valve whose leaflets are no longer functional, and white arrow indicates the new transcatheter balloon expandable valve that was deployed overlapping the top end of the first valve.



Fig 13.40


On fluoroscopic imaging, the combination of valves is indicated by white arrow. In real time, no aortic regurgitation is seen.


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Jan 2, 2020 | Posted by in CARDIOLOGY | Comments Off on Transcatheter valve therapies

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