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\begin{document}

\title{A vegetation on the surface of left ventricular muscle and subvalvular
tissue just below the anterolateral commissure of the mitral valve
without exposure to regurgitation or shunt jet}



\author[1]{kenji masada}%
\author[1]{Hironori Ueda}%
\author[1]{Masamichi Ozawa}%
\author[1]{Norimasa Mitsui}%
\author[2]{hiroto utsunomiya}%
\author[1]{Shinya Takahashi}%
\affil[1]{Affiliation not available}%
\affil[2]{Cedars-Sinai Heart Institute}%


\vspace{-1em}



  
  \date{May 26, 2024}


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\selectlanguage{english}
\begin{abstract}
Bacteria can adhere to cardiac endothelium damaged by regurgitation or
shunt jet; however, healthy cardiac endothelium is supposedly resistant
to bacterial adhesion. Bacterial vegetations are most common on cardiac
valves, but are rarely observed at other sites. We report a case of a
vegetation on the surface of left ventricular muscle/subvalvular tissue
without regurgitation or shunt jet. Transthoracic echocardiography did
not detect the vegetation because of its unique location; however,
transesophageal echocardiography (TEE) did detect. In conclusion,
vegetations can form without exposure to regurgitation or shunt jet, and
TEE is highly sensitive for detecting the vegetation in unusual
locations.%
\end{abstract}%



\sloppy


\textbf{A vegetation on the surface of left ventricular muscle and
subvalvular tissue just below the anterolateral commissure of the mitral
valve without exposure to regurgitation or shunt jet}

Running head: A vegetation in the unique location

Kenji Masada\textsuperscript{1}, MD, PhD; Hironori
Ueda\textsuperscript{1}, MD, PhD; Masamichi Ozawa\textsuperscript{2},
MD, PhD; Norimasa Mitsui\textsuperscript{2}, MD, PhD; Hiroto
Utsunomiya\textsuperscript{3}, MD, PhD; Shinya
Takahashi\textsuperscript{4}, MD, PhD

\textsuperscript{1}Department of Cardiovascular Medicine, Hiroshima
Prefectural Hospital, Hiroshima, Japan

\textsuperscript{2}Department of Cardiovascular Surgery, Hiroshima
Prefectural Hospital, Hiroshima, Japan

\textsuperscript{3}Department of Cardiovascular Medicine, Hiroshima
University Graduate School of Biomedical

and Health Sciences, Hiroshima, Japan

\textsuperscript{4}Department of Cardiovascular Surgery, Hiroshima
University Graduate School of Biomedical

and Health Sciences, Hiroshima, Japan

Address for correspondence:

Kenji Masada, MD, PhD

Department of Cardiovascular Medicine, Hiroshima Prefectural Hospital,
Hiroshima, Japan, 1-5-54 Ujina Kanda, Minami-ku, Hiroshima 734-8530,
Japan

Telephone: +81-82-254-1818

Fax: +81-82-256-3569

Email: kmasada-hrs@umin.ac.jp

\textbf{Abstract}

Bacteria can adhere to cardiac endothelium damaged by regurgitation or
shunt jet; however,

healthy cardiac endothelium is supposedly resistant to bacterial
adhesion. Bacterial vegetations are most common on cardiac valves, but
are rarely observed at other sites. We report a case of a

vegetation on the surface of left ventricular muscle/subvalvular tissue
without regurgitation or shunt jet. Transthoracic echocardiography did
not detect the vegetation because of its unique

location; however, transesophageal echocardiography (TEE) did detect. In
conclusion, vegetations can form without exposure to regurgitation or
shunt jet, and TEE is highly sensitive for detecting the vegetation in
unusual locations.

\textbf{Keywords:} infective endocarditis, vegetation, transthoracic
echocardiography, transesophageal

echocardiography, regurgitation, shunt jet

\textbf{Case Report}

A 22-year-old man with a fever was admitted as an emergency patient. At
presentation, his body

temperature was 40.3, and physical examination revealed no obvious
cardiac murmur.

However, there was evidence of splinter hemorrhages and Janeway lesions.
Although transthoracic echocardiography (TTE) revealed no obvious
vegetation or significant valvular disease (Figure 1A; Movie S1), blood
cultures grew gram-positive cocci in clusters, which were identified as
methicillin-sensitive \emph{Staphylococcus aureus} . Therefore, we
performed transesophageal echocardiography (TEE), suspecting infective
endocarditis (IE). TEE revealed a mobile vegetation measuring 15 \selectlanguage{ngerman}× 7 mm
on the surface of left ventricular muscle just below the anterolateral
commissure of the mitral valve (Figure 1B; Movie S2), but no significant
valve stenosis or regurgitation\selectlanguage{english}.IE was diagnosed according to the
modified Duke criteria. According to the American Heart Association
guidelines, early surgery is recommended for class \selectlanguage{english}IIa in patients with
severe valve regurgitation and mobile vegetations \textgreater{} 10 mm
in size\textsuperscript{1}. In our case, severe valve regurgitation was
not seen, but the \textgreater{} 10-mm mobile vegetation was thought to
involve a risk of embolism. Therefore, resection of the vegetation was
performed on the seventh day. Surgical findings revealed that a
vegetation existed on the surface of left ventricular muscle just below
the anterolateral commissure of the mitral valve, which partially
infiltrated subvalvular tissue (Figure 1C). A histological examination
of the vegetation revealed extensive inflammatory cell infiltration with
fibrin precipitation and necrotic tissue (Figure 1D).

Five days later, a new systolic cardiac murmur was ausculted. TTE and
TEE showed that moderate/severe mitral regurgitation owing to
anterolateral scallop flail leaflet. Chordal rupture supposedly occurred
due to infiltration of the vegetation; mitral valve plasty was performed
on the 19\textsuperscript{th} day. Postoperatively, the patient remained
stable. Penicillin G, 24 million units, was infused continuously over 24
hours, and blood cultures were consistently negative for 6 weeks. On the
26\textsuperscript{th} and 27\textsuperscript{th} day, we performed
18-Fluorodeoxyglucose positron emission tomography
(\textsuperscript{18}FDG-PET/CT) (Figure 1E) and gallium-67 scintigraphy
(Figure 1F). No abnormal accumulation in left ventricular muscle was
seen. The patient discharged on the 56\textsuperscript{th} hospital day.

Although the normal endothelial lining of the heart is resistant to
bacterial adhesion, bacteria are able to adhere to abnormal or damaged
endothelium in the presence of regurgitation or shunt
jet\textsuperscript{2}. A recent study revealed that vegetations exist
mostly on the valves or pacemaker leads; less than 3\% of vegetations
occur at other sites\textsuperscript{3}. We described a rare case of IE
that a vegetation on the surface of left ventricular muscle and
subvalvular tissue just below the anterolateral commissure of the mitral
valve without exposure to regurgitation or shunt jet. The results
of\textsuperscript{18}FDG-PET/CT and gallium-67 scintigraphy suggested
that vegetation did not exist on other lesions.

According to a previous review article, in patients with suspected
native valve endocarditis, TEE has a sensitivity of 90\% to 100\% and a
specificity of 90\% for detection of vegetations, and it is superior to
TTE\textsuperscript{4}. In the present case, IE could not be diagnosed
by TTE because of its unique location; however, TEE made it possible to
detect the vegetation. This case indicates the possibility that
vegetations may form without exposure to regurgitation or shunt jet.

\textbf{Acknowledgments}

None.

\textbf{Conflict of interests}

None.

\textbf{Data availability statement}

Data sharing is not applicable to this article as no new data were
created or analyzed in this study.

\textbf{Author contributions}

All authors contributed to patient care and to preparing the images and
writing/reviewing the manuscript. KM revised the manuscript attentively.
All authors read and approved the final manuscript.

\textbf{References}

\begin{enumerate}
\tightlist
\item
  Baddour LM, Wilson WR, Bayer AS, et al. American Heart Association
  Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of
  the Council on Cardiovascular Disease in the Young, Council on
  Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia,
  and Stroke Council. Infective endocarditis in adults: diagnosis,
  antimicrobial therapy, and management of complications. Circulation.
  2015;132:1435-1486.
\item
  Werdan K, Dietz S, Loffler B, et al. Mechanisms of infective
  endocarditis: pathogen-host interaction and risk states. Nat Rev
  Cardiol. 2014;11:35-50
\item
  Satoshi Nakatani, Kotaro Mitsutake, Takahiro Ohara, et al. Recent
  picture of infective endocarditis in Japan -- Lessons From Cardiac
  Disease Registration (CADRE-IE) --. Circ J. 2013;77:1558-1564
\item
  Thomas J. Cahill, Larry M. Baddour, Gilbert Habib, et al. Challenges
  in infective endocarditis. J Am Coll Cardiol. 2017;69:325-344
\end{enumerate}

\textbf{Figure Legends}

\textbf{Figure 1.}

A. Apical two-chamber transthoracic echocardiography view showing no
obvious vegetation.

B. Bicommissural transesophageal echocardiography view showing a mobile
vegetation (arrows) on the surface of left ventricular muscle just below
the anterolateral commissure of the mitral valve.

C. Resection of the vegetation approached from aortic valve was
performed on the seventh day of hospitalization. Surgical findings show
a vegetation (arrows) on the surface of left ventricular muscle and
subvalvular tissue just below the anterolateral commissure of the mitral
valve.

D. A histological examination of the vegetation shows extensive
inflammatory cell infiltration with fibrin precipitation and necrotic
tissue (hematoxylin and eosin, original magnification x 100).

E. 18-Fluorodeoxyglucose positron emission tomography shows no evidence
of abnormal accumulation in left ventricular muscle.

F. gallium-67 scintigraphy shows no evidence of abnormal accumulation in
left ventricular muscle.

LA = Left atrium; LV = left ventricle.

\textbf{Supporting information}

Additional supporting information may be found online in the Supporting
Information section.

Movie S1. Apical two-chamber transthoracic echocardiography view showing
no obvious vegetation. LA = Left atrium; LV = left ventricle.

Movie S2. Bicommissural transesophageal echocardiography view showing a
mobile vegetation on the surface of left ventricular muscle just below
the anterolateral commissure of the mitral valve. LV = Left ventricle.

\textbf{Hosted file}

\verb`Figure.pptx`  available at \url{https://authorea.com/users/727092/articles/709159-a-vegetation-on-the-surface-of-left-ventricular-muscle-and-subvalvular-tissue-just-below-the-anterolateral-commissure-of-the-mitral-valve-without-exposure-to-regurgitation-or-shunt-jet}

\selectlanguage{english}
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\end{document}

