Mitral valve disease







Normal mitral valve


CASE 2-1


Normal mitral valve anatomy



Fig 2.1


Anatomic view of the cardiac valves from the perspective of the base of the heart with the atria cut away and the great vessels transected. All four valves have a close anatomic relationship. In particular, the aortic valve is adjacent to the mitral valve along the midsegment of the anterior mitral leaflet. In the center frame a 3D image shows the mitral aortic relationship. In the right frame, the valve is seen from the ventricular aspect, and the three scallops of the posterior leaflet are appreciated.


(Reproduced with permission from Otto CM. Valvular Heart Disease 2e. Philadelphia: WB Saunders, 2004. ©2004, Elsevier Inc.)



Fig 2.2


Reference view displaying the mitral valve and its anatomic relationship to the aortic root (A) and the left atrial appendage (LAA) as seen from the left ventricular apex or TEE short-axis view. (B) Reference view demonstrating the relationship of the TEE imaging planes to the mitral valve with the probe positioned in the standard midesophageal position. (C) Surgical view of the mitral valve as seen from left atrium with the heart rotated. A1, A2, A3 = anterior leaflet sections; P1, P2, P3 = posterior leaflet sections.

(Reproduced with permission from Foster GP et al. Accurate localization of mitral regurgitant defects using multiplane transesophageal echocardiography. Ann Thoracic Surg 1998; 65:1025-1031. ©1998 Elsevier Inc.)







Fig 2.3


TEE in a four-chamber view at 0 degrees demonstrating the central section of the anterior leaflet (A2) and the central scallop of the posterior leaflet (P2). In the right frame, 3D TEE of the mitral valve is shown, illustrating how the view is developed.



Fig 2.4


TEE mitral commissural view, obtained here at 50 degrees by slight backward rotation from the two-chamber view, demonstrates the central segment of the anterior leaflet (A2) and the medial (P3) and lateral (P1) segments of the posterior leaflet.



Fig 2.5


TEE two-chamber view, obtained at 96 degrees, shows A1, A2, A3, and P3.



Fig 2.6


Further rotation to 130 degrees results in a long-axis view, again showing the central section of the anterior leaflet (A2) and the central scallop of the posterior leaflet (P2).



Fig 2.7


The transgastric short-axis view at the level of the mitral valve demonstrates the anterior mitral leaflet (AML) and the three scallops of the posterior leaflet (PML), along with the posterior (P-COM) and anterior commissures (A-COM). Rotation to about 90 degrees (96 degrees in this case) from the transgastric short axis provides a two-chamber view with visualization of the mitral leaflets, chords, and papillary muscles.



Fig 2.8


A model of the mitral valve with corresponding annular measurements is shown. A = anterior, P = posterior, AL = antero-lateral, PM = postero-medial.



Fig 2.9


The normal mitral valve in vivo, as seen after incisions in the right atrium, and the interatrial septum. On the left is the surgeon’s view from the right side of the operating table. On the right is the valve as it would appear on a basal transgastric short-axis TEE, as in Fig 2.7 .




Comments


The mitral valve apparatus is a complex structure in three dimensions that includes the saddle-shaped mitral annulus, leaflets, chords, and papillary muscles. The anterior leaflet is longer than the posterior leaflet but extends only about one third of the distance around the annulus circumference. The anterior leaflet does not have anatomically discrete segments, but location can be described as the lateral (A1), central (A2), and medial (A3) aspects of the leaflet. The posterior leaflet is shorter but extends a greater distance around the mitral annulus. The posterior leaflet typically has three discrete scallops: lateral (P1), central (P2), and medial (P3). Standard 2D and 3D TEE images are summarized in Table 2-1 . FLOAT NOT FOUND


Mitral regurgitant severity is best evaluated using multiple Doppler measures on a preoperative complete transthoracic echocardiogram (TTE). Decisions about timing of surgery are based not only on severity of regurgitation, but on clinical status and serial changes in left ventricular dimensions and systolic function. When regurgitant severity is reevaluated in the operating room (OR), regurgitant severity may be less than expected because of a lower afterload in the anesthetized versus awake patient. Useful measures of regurgitant severity in the OR include:



  • •

    Vena contracta width—narrowest diameter of the regurgitant jet at the valve orifice or just distal to it; for the mitral valve, best measured in the antero-posterior diameter (midesophageal long axis.)


  • •

    Proximal isovelocity surface area (PISA)—region of flow convergence on the ventricular side of the valve. The instantaneous regurgitant flow rate is the area of a hemisphere (2πr 2 ) times the aliasing velocity.


  • •

    Continuous wave (CW) Doppler—intensity and time course of the regurgitant velocity signal


  • •

    Regurgitant orifice area (ROA)—calculated from PISA and CW Doppler velocity as the instantaneous flow rate (cm 3 /s) divided by the maximum regurgitant jet velocity (cm/s) to yield the cross sectional area of regurgitant flow


  • •

    With primary MR, a ROA of 0.4 cm 2 or greater is consistent with severe MR. For secondary MR, a ROA of 0.2 cm 2 or greater is severe.


  • •

    Regurgitant volume can be calculated as the ROA times the velocity time integral of the MR jet: RV (mL or cm 3 ) = ROA (cm 2 ) × VTIMR (cm).


  • •

    The direction, size, and shape of the regurgitant jet are less useful for quantitation of severity but often help identify the mechanism of regurgitation because the direction of the jet typically is opposite the prolapsing leaflet; for instance, posterior leaflet prolapse results in an anteriorly directed jet. With severe leaflet restriction, the regurgitant jet is typically directed towards the restricted leaflet; for instance, posterior leaflet restriction results in a posteriorly directed jet.



Suggested reading




  • 1.

    Otto CM: Valvular regurgitation. In textbook of clinical echocardiography, ed 5, Philadelphia, 2013, Elsevier Saunders, pp 305–341.


  • 2.

    Hung J: Mitral regurgitation: Valve anatomy, regurgitant severity and timing of intervention. In Otto CM, editor: The practice of clinical echocardiography, ed 5, Philadelphia, 2016, Elsevier, Chapter 18.


  • 3.

    Zoghbi WA, Enriquez-Sarano M, Foster E, et al: Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography, J Am Soc Echocardiogr 16:777–802, 2003.


  • 4.

    Nishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 63:e57-e185, 2014.





Myxomatous mitral valve disease


CASE 2-2


Posterior leaflet prolapse with flail central (P2) scallop


A 46-year-old man with a 20-year history of a murmur was transferred from another hospital with increasing shortness of breath and hemoptysis of 1 month’s duration. A loud holosystolic murmur at the apex was noted on physical examination. Because the patient also had a long history of intravenous drug use, blood cultures were obtained and the patient was started on empiric intravenous antibiotics for possible endocarditis.


Transthoracic echocardiography showed severe mitral regurgitation with a posterior leaflet flail segment and an anteriorly directed regurgitant jet. Left ventricular size was at the upper limits of normal (end-systolic dimension 39 mm) with an ejection fraction of 60%. The left atrium was moderately enlarged and pulmonary pressures were severely elevated with an estimated systolic pressure of 70 mm Hg. Transesophageal echocardiography was performed to evaluate for possible vegetations. This study demonstrated a flail central scallop of the posterior leaflet with severe mitral regurgitation. He was referred for mitral valve surgery.



Fig 2.10


Intraoperative 2D images of the mitral valve from a high esophageal position at 0 degrees rotation show the relatively thin anterior leaflet with normal motion and a thickened, redundant posterior leaflet. The flail segment of the posterior leaflet is seen on the atrial side of the annulus with the tip of the leaflet pointing away from the left ventricular apex. In contrast, with severe prolapse but intact chordae, there is bowing of the leaflet into the atrium, with the leaflet tip still pointing toward the ventricular apex.



Fig 2.11


Rotation of the 2D-image plane to 28 degrees (left) more clearly demonstrates the flail middle scallop of the posterior leaflet (P2) with a torn chord on the left atrial side of the valve in systole. Color flow Doppler at 42 degrees rotation (right) demonstrates a wide eccentric mitral regurgitant (MR) jet with flow acceleration on the ventricular side of the valve. The jet is directed away from the affected leaflet; for example, an anteriorly directed jet with posterior leaflet disease.



Fig 2.12


Further rotation of the image plane to the mitral commissural view (63 degrees) shows the severe prolapse and partial flail of the central scallop of the posterior leaflet (P2). Color Doppler (right) in the mitral commissural plane shows significant mitral regurgitation.



Fig 2.13


In the upper two frames, rotation of the 2D-image plane to 127 degrees (left) also demonstrates the flail middle scallop of the posterior leaflet (P2). Color flow Doppler at 127 degrees rotation (right) also demonstrates a wide eccentric mitral regurgitant (MR) jet with flow acceleration on the ventricular side of the valve and a vena contracta width of 9 mm. The jet is directed away from the affected leaflet—for example, an anteriorly directed jet with posterior leaflet disease. In the lower three frames 3D TEE of the mitral valve is illustrated from the left atrial perspective (left) , from the medial side of the mitral valve with the most medial aspect cropped away (center) , and from the left ventricular perspective (right) . The white arrows indicate the flail P2 segment, the red arrows indicate torn chordae, and the green arrows indicate thickened subvalvular chordae.



Fig 2.14


Approach to mitral valve repair. (1) The mitral valve may be approached through the dome of the left atrium, having developed Sondergaards’s plane by blunt and sharp dissection. (2) The mitral valve may also be approached through the right atrium and interatrial septum. (3) The diseased P2 is excised, the remainder of the posterior leaflet reapproximated, and an annuloplasty ring secured (A–E).

(Cohn L. Mitral valve repair: Operative techniques in thoracic and cardiovascular surgery 1998; 3(2):109–125. Reprinted with permission.)



Fig 2.15


Intraoperative visualization of the valve confirmed the flail middle scallop of the posterior leaflet with the surgical view shown on the left and the resected leaflet segment shown on the right. The anterior mitral leaflet was normal but there were three sets of ruptured chords to the central scallop of the posterior leaflet (P2) (arrows). There was no evidence for vegetation or abscess. The video shows that after resection of the flail leaflet segment and reapproximation of the leaflet edges, an annuloplasty ring was placed with the sutures positioned in the annulus and then the ring positioned.



Fig 2.16


Postrepair images at 0 degrees show increased echogenicity of the posterior leaflet and the annuloplasty ring, with normal leaflet closure in systole on 2D imaging (left) and the absence of mitral regurgitation on color flow imaging (right).



Fig 2.17


Postrepair images in a long-axis view (131 degrees) show the annuloplasty ring (arrow) and the site of the posterior leaflet resection and repair (left) . It is important to evaluate for regurgitation in multiple views; no regurgitation is seen with color flow imaging in this view (right).



Fig 2.18


Pulsed Doppler evaluation of flow in the left upper pulmonary vein shows normal diastolic and systolic atrial inflow (top) . In contrast, the prerepair pulmonary venous flow (bottom) shows holosystolic reversal of flow (arrow) consistent with severe mitral regurgitation.





Fig 2.19


In another patient with similar pathology and an identical procedure, postoperative TEE in the four-chamber view showed systolic anterior motion (SAM) of the anterior mitral leaflet (arrow) (left) . After adjustment of loading conditions, the SAM resolved (right).



Fig 2.20


In a case with a similar clinical presentation, 3D TEE en face view in systole shows torn chordae (red arrows) and a flail P2 segment. There appears to be prolapse of P1 (left) . In the middle, software reconstruction shows the prolapsing P2 and P1 segments. On the right the excised segment with torn chordae (red arrows) is seen. A = anterior, P = posterior, AL = antero-lateral, PM = postero-medial.



Fig 2.21


The flail segment was resected, and an annuloplasty ring placed. The anterior leaflet has a dropout defect (red arrow) but functions as a monocusp, and completely covers the mitral orifice during systole; in real time it can be appreciated that the posterior leaflet is much reduced in size.



Fig 2.22


In a similar case, a complete annuloplasty ring is chosen, as opposed to the C-shaped ring used in the first case.



Fig 2.23


In another patient with an excision of the P3 scallop, postoperative imaging revealed a very eccentric jet (white arrow) through the repaired posterior leaflet (white arrow) , suggesting that the posterior leaflet closure was not intact. This was confirmed on reexploration, and re-repaired. (The annuloplasty ring is indicated by the red arrows.)




CASE 2-3


Posterior leaflet prolapse of medial (P3) scallop


The patient is a 79-year-old woman who states that she was in reasonable health until 3 months before admission, when she was admitted to an outside hospital with severe shortness of breath and was found to have heart failure. An echocardiogram showed severe mitral regurgitation and a massively enlarged left atrium, an enlarged left ventricle and ejection fraction of 55%. Based on the presence of severe mitral regurgitation with heart failure symptoms and an ejection fraction over 30%, she had an ACC/AHA Class I indication for intervention; thus she was referred for mitral valve surgery.



Fig 2.24


Preoperative MRI. In this two-chamber view, a jet of MR (arrow) as well as an enlarged left atrium is seen.



Fig 2.25


In this midesophageal, four-chamber view, A2 and P2 are seen coapting during systole; however, an apparent echolucent circular mass is seen in the left atrium, which does not appear to connect to the mitral valve in this tomographic view. The left atrium is enlarged.



Fig 2.26


In this midesophageal commissural view, the mitral leaflets move normally during diastole; however, during systole, P3 prolapse occurs; therefore, this view confirms that the apparent “mass” seen in the left atrium in the four-chamber view is in fact the P3 scallop.



Fig 2.27


The multiplane angle is rotated to obtain a two-chamber view, in which P3 is again seen to be prolapsing; in the right frame, a broad jet of MR with a vena contract width of 8 mm is seen.



Fig 2.28


3D TEE of the mitral valve from the LA perspective. In systole, a thickened and prolapsing P3 scallop is seen (left); on the right, during diastole, with the image slightly rotated, the P3 segment moves very little, and is seen to be encroaching on the medial commissure (red arrow) . Because of this, the valve was deemed irreparable, and was replaced with a bileaflet mechanical prosthesis.




CASE 2-4


Anterior leaflet prolapse of medial (A3) scallop


Two years before admission, when still living in Mexico, this 27-year-old male presented with left-sided chest pain, progressive shortness of breath on exertion, and tingling in his fingers. An echocardiogram was done, which showed that he had mitral valve prolapse with at least moderate mitral regurgitation. Although surgery was contemplated, the patient declined. He was doing relatively well and moved to this region approximately 4 months ago. However, recently he began to have some more chest discomfort, as well as tingling in his fingers. He saw his primary care doctor who referred him for echocardiography which showed severe MR with normal LV systolic function but with significant LV dilation. The decision was made to proceed with mitral valve surgery.



Fig 2.29


2D imaging in a posteriorly angulated four-chamber view at 0-degrees rotation during systole demonstrates normally functioning A2 and P2 segments; however, there is presumably a flail segment of one of the mitral leaflets (arrow) . Color flow imaging showed a posteriorly directed mitral regurgitant jet, which is most consistent with anterior leaflet disease.



Fig 2.30


Pulsed wave Doppler in the right upper pulmonary vein (RUPV) is normal. In the left upper pulmonary vein (LUPV), two components of the systolic (S) wave are evident—the S1 wave is a result of atrial relaxation, and the reversed S2 wave is a result of severe MR.


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Dec 30, 2019 | Posted by in CARDIOLOGY | Comments Off on Mitral valve disease

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