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Echocardiographic Recognition of Mitral Valve Involvement in Primary Aortic Valve Endocarditis

Rao, Srikantha L., MBBS, MS*; Campbell, David B., MD; Haouzi-Judenherc, Annick R., MD, FASE

doi: 10.1213/ANE.0b013e3181fe756b
Cardiovascular Anesthesiology: Echo Rounds
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Published ahead of print October 21, 2010

From the *Department of Anesthesiology, Department of Surgery, and Department of Cardiology, Penn State Milton S. Hershey Medical Center, Penn State College of Medicine, Hershey, Pennsylvania.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.anesthesia-analgesia.org).

The funding for this manuscript was provided by departmental sources.

The authors report no conflict of interest.

Address correspondence to Srikantha L. Rao, MBBS, MS, Department of Anesthesiology, H187 Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033. Address e-mail to srao1@hmc.psu.edu.

Accepted September 7, 2010

Published ahead of print October 21, 2010

A 65-year-old diabetic man, presenting with new onset fever and altered mental status, was readmitted to our hospital from a skilled nursing facility at which he had been receiving IV antibiotics for aortic valve endocarditis. Blood cultures now yielded Streptococcus viridans. After a transesophageal echocardiogram (TEE) showed new severe mitral regurgitation (MR), he was scheduled for mitral and aortic valve replacement surgery. Consent for publication of this case was obtained from the patient.

Intraoperative TEE examination confirmed the diagnosis of aortic valve endocarditis. In the midesophageal (ME) long-axis view of the aorta and left ventricle with color-flow Doppler (CFD), severe aortic regurgitation was seen, with a wide jet directed towards the anterior mitral leaflet (AML). In the ME 4-chamber (ME 4C) view, an 11 × 20 mm echogenic mobile mass, attached to a flail right aortic valve leaflet that prolapsed through the left ventricular outflow tract (LVOT) contacting the AML during diastole, was seen (Fig. 1, left panel) (Video 1; see Supplemental Digital Content 2, http://links.lww.com/AA/A201; see Appendix for video legends). The ME aortic valve short-axis view confirmed that this large vegetation was attached to the right aortic valve leaflet (Video 2; see Supplemental Digital Content 4, http://links.lww.com/AA/A203; see Appendix for video legends). Upon further interrogation of the aortic root using ME aortic valve short- and long-axis views, there was no evidence of direct extension of infection into the aortic annulus.

Figure 1

Figure 1

The left ventricle was mildly dilated, with reduced systolic function (left ventricular ejection fraction ∼50%). CFD in the ME 4C view demonstrated 2 systolic jets in the left atrium. A central jet, located at the coaptation margin of the mitral valve, was consistent with functional MR possibly because of ventricular dilation. A second eccentric “mitral” regurgitation jet was caused by a perforation of the AML and was located at the (previously described) aortic vegetation's contact point with the AML (Video 3; see Supplemental Digital Content 6, http://links.lww.com/AA/A205; see Appendix for video legends). This eccentric jet was visualized on frame-by-frame analysis in 1 plane: a modified ME 4C view with probe retroflexed, and the image plane angle increased to 11° (Fig. 2), thereby localizing the perforation to the A1–A2 segment junction of the AML. This jet displayed flow convergence over the AML perforation and impinged on the lateral wall of the left atrium and swirled in the left atrium, thereby displaying a Coanda effect. (Wall-impinging jets appear significantly smaller than do centrally directed jets of similar hemodynamic severity, mainly because they flatten out on the wall of the receiving chamber.) This eccentric jet also appeared to have a longer duration than does the central MR jet. Subsequent analysis revealed that a portion of the aortic regurgitant jet in the LVOT continued to flow through the perforation in the AML and caused a diastolic MR jet, contributing to this appearance (Fig. 1, right panel).

Figure 2

Figure 2

The aortic valve was replaced with a 23-mm pericardial prosthesis. The perforation in the AML was closed by a simple suture repair, avoiding the planned mitral valve replacement. The patient was weaned from cardiopulmonary bypass on minimal inotropic support. Postbypass TEE interrogation revealed a well-functioning prosthetic aortic valve with no perivalvular leak and trivial MR. The patient was discharged on the 6th postoperative day.

Aortic valve endocarditis may be complicated by perivalvular extension of infection into the aortic root. A systematic approach to TEE interrogation of this area using ME aortic valve short- and long-axis views in 2-dimensional and color-flow imaging is recommended.1 In addition to aortic root abscess, contiguous spread of vegetative material can occur into adjacent areas, especially the relatively avascular mitral–aortic intervalvular fibrosa. An aneurysm of the mitral–aortic intervalvular fibrosa may perforate into the left atrium, causing an aorto–atrial fistula, in which flow from the aorta to the atrium would be throughout the cardiac cycle. However, this flow could be visualized predominantly in systole as an eccentric systolic jet in the left atrium on TEE that may then be misinterpreted as MR.2

In addition to direct extension of infection into subaortic structures, aortic valve endocarditis can also be complicated by mitral valve involvement, especially from aortic vegetations (larger than 6 mm) that prolapse into the LVOT, contacting the ventricular aspect of the AML (“mitral kissing vegetation”). Secondary mitral infection occurs in <10% of such patients.3 The aortic regurgitant jet impinging upon the AML can cause mechanical damage (including a perforation) with or without subsequent infection (“jet perforation”).3,4 Therefore, secondary mitral valve complications must be actively sought in primary aortic endocarditis even if there is no evidence of contiguous spread of infection. When MR is noted, intraoperative TEE should be used to study the valvular structure, assess regurgitation severity, identify its mechanism, including the location of the lesion to specifically determine whether the mitral valve can be repaired, as well as to evaluate the impact of volume overload on the various cardiac chambers.

A systematic approach to examining the mitral valve by using 2-dimensional and Doppler echocardiography in multiple ME views along with a transgastric basal short-axis view should be used. Several indexes, specifically developed to comprehensively evaluate the severity of regurgitation, should be determined using qualitative and quantitative methods from CFD, pulse wave, and continuous-wave Doppler in these same views (color-flow jet area, vena contracta width, mitral inflow, pulmonary vein flow, regurgitant volume, and fraction).5 The transgastric basal short-axis view of the mitral valve is useful to diagnose clefts and perforations, and CFD provides additional information on the origin of the regurgitant jets, and M-mode ultrasound may be used to assess timing of MR.

In patients with proven infective endocarditis, surgery of the native valve is indicated (Class I indication) in the presence of destructive penetrating lesions (e.g., sinus of Valsalva to right atrium, right ventricle, or left atrium fistula; mitral leaflet perforation with aortic valve endocarditis; or infection in annulus fibrosa). When possible, the mitral valve should be repaired instead of being replaced in the setting of active infection because of the risk of infection of prosthetic materials. Intraoperative TEE is indicated to establish the anatomic basis of severe MR to assess feasibility of repair and to guide repair.

In our patient, intraoperative TEE confirmed that mitral leaflet perforation was the cause of the severe MR, thus providing important clinical information that minimized the scope and risk of the surgery (prosthetic material and additional bypass time were avoided), thereby improving his long-term prognosis and survival.6 It reaffirms that an accurate diagnosis of subaortic complications using TEE is crucial to patient management.7

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REFERENCES

1. Stechert MM, London MJ. Native aortic root endocarditis with invasion of the right outflow tract. Anesth Analg 2010;110:36–8
2. Stechert MM, Kellermeier JP. Aorto–atrial fistula: an important complication of aortic prosthetic valve endocarditis. Anesth Analg 2007;105:332–3
3. Piper C, Hetzer R, Körfer R, Bergemann R, Horstkotte D. The importance of secondary mitral valve involvement in primary aortic valve endocarditis; the mitral kissing vegetation. Eur Heart J 2002;23:79–86
4. Frogel JK, Weiss SJ, Kohl BA. Transesophageal echocardiography diagnosis of coronary sinus thrombosis. Anesth Analg 2009;108:441–2
5. Zoghbi WA, Enriquez-Sarano M, Foster E, Grayburn PA, Kraft CD, Levine RA, Nihoyannopoulos P, Otto CM, Quinones MA, Rakowski H, Stewart WJ, Waggoner A, Weissman NJ. Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography. J Am Soc Echocardiogr 2003;16:777–802
6. Karalis DG, Bansal RC, Hauck AJ, Ross JJ Jr, Applegate PM, Jutzy KR, Mintz GS, Chandrasekaran K. Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications. Circulation 1992;86:353–62
7. Sexton DJ, Spelman D. Current best practices and guidelines. Assessment and management of complications in infective endocarditis. Cardiol Clin 2003;21:273–82
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APPENDIX: Online Echocardiographic Still and Video Images

Video 1: Midesophageal 4-chamber view displays a large vegetation attached to a flail right aortic leaflet prolapsing through the left ventricular outflow tract (LVOT), contacting the anterior mitral leaflet during ventricular diastole. LA = left atrium; RV = right ventricle.

Video 2: Midesophageal aortic valve short-axis view displays the vegetation attached to the right aortic leaflet briefly disappearing from the visual plane as it prolapses into the left ventricular outflow tract (LVOT). LA = left atrium; RV = right ventricle.

Video 3: A modified midesophageal 4-chamber view with color-flow Doppler (with the probe slightly retroflexed and the image plane increased to 11°). Two systolic jets are seen in the left atrium (LA). In early systole, a central systolic jet of mitral regurgitation is seen. Later in systole, an eccentric jet, caused by the perforation in the anterior mitral leaflet that encircles the LA, is seen. The eccentric jet is located at the prolapsing aortic vegetation's contact point with the mitral leaflet. The regurgitant flow through the perforation was “biphasic,” with a larger systolic component and a smaller diastolic component. Note that a portion of the aortic regurgitant jet (asterisk) passes through the perforation in the mitral leaflet, causing a diastolic mitral regurgitation (MR). LA = left atrium; RA = right atrium; LV = left ventricle.

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Clinicians' Key Teaching Points By Martin Stechert, MD, Nikolaos J. Skubas, MD, and Martin J. London, MD
  • Aortic valve endocarditis usually begins with verrucous lesions of the cusps that may extend to the aortic root with formation of abscess or fistula tracts. Mitral valve involvement occurs in 10% of patients, either by contiguous spread along the mitral–aortic intervalvular fibrosa or by physical contact of a large prolapsed aortic vegetation with the anterior mitral leaflet (“kissing vegetation”).
  • A detailed systematic transesophageal echocardiogram (TEE) evaluation (including color Doppler and M-mode imaging) of the aortic valve and aortic root (midesophageal [ME] short-axis and long-axis views) should be performed to evaluate vegetations or cusp perforations resulting in aortic insufficiency and abscesses or fistula formation resulting in abnormal chamber communication.
  • In this case, a right coronary cusp vegetation prolapsing into the left ventricular outflow tract caused perforation of the anterior mitral leaflet, resulting in a posteriorly directed systolic mitral regurgitation jet. Diastolic mitral regurgitation was also noted, caused by the aortic insufficiency jet entering the left atrium through the mitral perforation. TEE was used to image the origin, mechanism, and timing of these regurgitant jets and differentiate them from a cleft mitral leaflet or an aorto-left atrial communication.
  • Secondary involvement of the mitral valve in aortic valve endocarditis is a common occurrence and should be investigated routinely in ME and transgastric views. TEE is superior to other imaging modalities for the examination of subaortic complications of infectious endocarditis involving the mitral valve.

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