Anesth Analg 2008; 107:1822-1824
© 2008 International Anesthesia Research Society
doi: 10.1213/ane.0b013e318185d12e
CARDIOVASCULAR ANESTHESIOLOGY
Mitral Valve Prolapse and Systolic Anterior Motion Illustrated by Real Time Three-Dimensional Transesophageal Echocardiography
Bettina Jungwirth, MD*,
David B. Adams, RCS, RDCS ,
Joseph P. Mathew, MD, FASE*,
Madhav Swaminathan, MD, FASE*,
Donald D. Glower, MD , and
G. Burkhard Mackensen, MD, PhD, FASE*
From the *Department of Anesthesiology, Division of Cardiothoracic Anesthesiology and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina; Department of Medicine, Division of Cardiology, Duke University Medical Center, Durham, North Carolina; and Department of Surgery, Division of Cardiovascular and Thoracic Surgery, Duke University Medical Center, Durham, North Carolina.
Address correspondence to G. Burkhard Mackensen, MD, PhD, FASE, Department of Anesthesiology, Duke University Medical Center, Box 3094, Durham, NC 27710. Address e-mail to b.mackensen{at}duke.edu.
A 56-yr-old man presented with increasing dyspnea with mild to moderate exercise. Transthoracic echocardiography demonstrated hypertrophic obstructive cardiomyopathy (HOCM), systolic anterior motion (SAM) of the anterior mitral valve (MV) leaflet, with a left ventricular outflow tract (LVOT) peak velocity of 4.2 m/s at rest (obtained from an apical window) and moderate to severe mitral regurgitation (MR). In agreement with current consensus guidelines, the patient was scheduled for left ventricular surgical septal myectomy.1 The intraoperative two-dimensional transesophageal echocardiography (2D-TEE) before cardiopulmonary bypass confirmed the diagnosis of marked HOCM, SAM, and severe MR and identified a prolapse of the P2 scallop of the posterior mitral leaflet (PML) using standard midesophageal (ME) views (Video Clip 1; please see video clip available at www.anesthesia-analgesia.org). Severe MR was confirmed by both, a vena contracta of 7 mm and systolic reversal during Doppler interrogation of the pulmonary venous flow. Of note, the MR jet peaked in mid and late systole based on color flow Doppler. The MR jet originated anteriorly and was then directed centrally and slightly posteriorly, suggesting a significant role of SAM rather than PML prolapse alone in the etiology of MR (Video Clip 1).2 The diastolic interventricular septal thickness measured 26 mm in the ME long axis view. M-mode assessment of the aortic valve in the ME aortic valve long axis view confirmed dynamic outflow tract obstruction, as leaflets opened initially, but closed in mid systole. Therefore, the patient underwent left ventricular septal myectomy aiming to alleviate LVOT obstruction and SAM and ultimately to improve the degree of MR.2 However, 2D-TEE assessment after myectomy demonstrated unaltered MR and persistent SAM of the MV, prompting the surgeon to replace the MV with a low profile mitral prosthesis (29 mm mechanical St. Jude prosthesis). Immediate MV replacement, rather than an attempt to repair the MV, was selected to avoid the possibility of a third cardiopulmonary bypass run in case of an insufficient repair. Postoperative 2D-TEE and Doppler assessment showed the typical echocardiographic signature of a bileaflet tilting disk valve with no residual regurgitation and no residual outflow tract gradient, and the patient had an unremarkable recovery.
This case of complex MV disease in the context of SAM and HOCM highlights the potential difficulties in identifying the etiology of MR. Specifically, it demonstrates the diagnostic dilemma to discern the contribution of SAM of the MV versus intrinsic disease of the MV apparatus by using conventional 2D-TEE. In this context, novel techniques, such as the recently introduced real time three-dimensional (RT-3D)-TEE, may soon help to better guide the surgical approach and predict postoperative outcome. In this case, RT-3D-TEE was performed in addition to 2D-TEE using the recently released RT-3D-TEE Matrix transducer (IE33 system; Philips Medical Systems, Andover, MA). The 3D en-face view of the MV is in accordance with the surgical view and is particularly suited to illustrate the complex structure of the MV apparatus including possible abnormalities. In this patient, RT-3D-TEE revealed a myxomatous and prolapsed PML and a significant malcoaptation between the A1/A2 and P1/P2 scallops of the MV in mid and late systole while both leaflets moved anteriorly (Fig. 1, Video Clip 2; please see video clip available at www.anesthesia-analgesia.org). Three-D imaging of the LVOT and MV from the left ventricular side confirmed this pronounced anterior movement of both leaflets and the lack of coaptation during the second half of systole. This lack of coaptation is in part due to the failure of the PML to move as much forward as the anterior mitral valve leaflet (AML) (Video Clip 3; please see video clip available at www.anesthesia-analgesia.org).3 RT-3D-TEE also allows for spatial assessment of the extent of maximal septal thickness, the degree of LVOT obstruction and the intimate relationship between MV and LVOT (e.g., the extent of systolic mitral leaflet-to-septal contact), important information that may assist the surgeon to optimize the site and size of the septal myectomy.4 As shown by Willert et al., 3D-TEE might be especially helpful when patients present with a combination of both obstruction of the LVOT as well as intrinsic MV pathology.5 In addition to information provided by Willert et al., our case emphasizes the novelty of real-time assessment of the MV and the LVOT and introduces additional features obtained by using available built-in software. Careful cropping of the 3D image of the LVOT at the point of maximal AML-septal contact revealed a diastolic LVOT area of 6.25 cm2 which significantly decreased to 4.57 cm2 during systole (Figs. 2A and B). Although this initially may seem as a large systolic cross-sectional area, this remaining space was almost completely covered with the anteriorly moved AML. Also, by using available built-in software (e.g., Q-LAB, Philips Medical Systems, Andover, MA), additional information may be obtained. In our case, this included an anterolateral to posteromedial diameter of the MV annulus of 5.3 cm and an anterior to posterior diameter of the MV annulus of 4.1 cm (compared to 4.1 cm measured with 2D-ME 4 chamber view during early diastole and 5.5 cm measured with 2D-ME 2 chamber view). Additionally, the software was able to identify the location of prolapsed scallops (Fig. 3). Further, as typically seen in patients with HOCM, this patient had an unusually long posterior MV leaflet and a decreased ratio of AML/PML (AML 2.2 cm by RT-3D-TEE compared to 3.1 cm by 2D-TEE and PML 2.7 cm by RT-3D-TEE and 2.8 cm by 2D-TEE), which could have independently contributed to the dynamic obstruction of the LVOT. Finally, RT-3D-TEE lends itself as a superb educational tool to demonstrate the spatial relationship between the MV and its surrounding structures, and explain complex pathophysiology such as SAM and LVOT obstruction to trainees in echocardiography, anesthesia, and surgery.
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Figure 1. The en-face view of the mitral valve corresponding to the surgical view obtained by real-time three-dimensional transesophageal echocardiography. The posterior mitral leaflet appears myxomatous and prolapsed (P1/P2 scallops). PML = posterior mitral leaflet; AML = anterior mitral valve leaflet; ALC = anterolateral commissure; PMC = posteromedial commissure; Ao = aortic valve.
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Figure 2. Three-dimensional image of the left ventricular outflow tract (LVOT) at the point of maximal anterior mitral leaflet (AML)-septal contact. Cropping of this image revealed a diastolic LVOT area of 6.25 cm2 (A) which significantly decreased to 4.57 cm2 during systole (B). LVOT = left ventricular outflow tract; AML = anterior mitral leaflet.
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Figure 3. Advanced three-dimensional model of the mitral valve generated using built-in software (Q-LAB, Philips Medical Systems, Andover, MA). This model confirms the prolapse of the P1 and P2 scallops of the posterior mitral leaflet and allows for a quantitative approach to MV assessment. A = anterior mitral leaflet; P = posterior mitral leaflet; AL = anterolateral commissure; pm = posteromedial commissure; Ao = aortic valve.
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In summary, RT-3D-TEE is a recently introduced technique providing the perioperative caregiver with live 3D echocardiographic images. These images are easily acquired, avoid time-consuming offline reconstruction, and may provide additional information not previously known. In the case presented, retrospective analysis of the RT-3D-TEE dataset revealed additional information about the abnormalities of the MV apparatus, especially related to the extensive role of SAM in the LVOT obstruction. RT-3D-TEE at this point remains a new technique and more experience and prospective studies are needed to fully assess its additional value. However, this case illustrates the potential for RT-3D-TEE compared to conventional 2D-TEE to provide additional information which might support changes in surgical planning and potentially improve outcome.
Footnotes
This article has supplementary material on the Web site: www.anesthesia-analgesia.org.
Accepted for publication June 25, 2008.
Reprints will not be available from the author.
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