Patent Foramen Ovale: Current Pathology, Pathophysiology, and Clinical Status
Hidehiko Hara, MD*,
Renu Virmani, MD ,
Elena Ladich, MD,
Shannon Mackey-Bojack, MD ,
Jack Titus, MD,
Mark Reisman, MD ,
William Gray, MD,
Masato Nakamura, MD||,
Michael Mooney, MD*,
Anil Poulose, MD* and
Robert S. Schwartz, MD*,*
* Minneapolis Heart Institute and Foundation, Minneapolis, Minnesota
CV Path, International Registry of Pathology, Gaithersburg, Maryland
Jesse E. Edwards Registry of Cardiovascular Disease, St. Paul, Minnesota
Swedish Medical Center, Seattle, Washington
|| Division of Cardiovascular Medicine, Toho University Ohashi Hospital, Tokyo, Japan
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Figure 1 Diagrammatic representation of patent foramen ovale development from embryology. Right sagittal and coronal views. Adapted from Konstantinides et al. (8). LA = left atrium; RA = right atrium.
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Figure 2 Gross anatomy of the patent foramen ovale. (a) View from the right atrium showing a patent foramen ovale. Patency is determined by probing. The limbus (arrow) is seen forming a rounded cuff around the valve of the foramen ovale. The anatomic locations relative to the coronary sinus (CS) and tricuspid valve (S = septal leaflet; A = anterior leaflet) can be appreciated. (b) Same case viewed from the left atrium with probe demonstrating patency. The anterior leaflet of the mitral valve is seen below the probe.
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Figure 3 Histopathology of the tissue membranes constituting a patent foramen ovale. (a) Longitudinal section of the atrial septum, showing a patent foramen ovale (box) with valve (arrow). The superior epicardial surface (E) and a portion of the mitral valve (MV) are also seen. The septal wall consists predominantly of myocardium and adipose tissue. RA = right atrium. (b) A higher magnification of boxed area in panel a, showing the valve with a thickened fibrotic right endocardial surface (arrow). The atrial septum (*) in this region consists of myocardium and becomes predominantly fibrotic inferiorly. Movat x1.25. (c) A higher magnification of the valve from the left side, showing a relatively thin endocardial surface (arrow). The underlying myocardium is composed of bundles of cardiac myocytes. Movat x20. (d) A higher magnification of the valve from the opposite side (right), highlighting the endocardial surface (arrow), which consists of a thick layer of collagen and elastic fibers. Movat x20.
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Figure 4 (a) Posterior longitudinal section of the atrial septum from the same case shown in Figure 3. The limbus (*) and valve (arrow) of the foramen ovale are indicated. A portion of mitral valve (MV) is seen at the inferior margin. (b) Boxed area demonstrates the area where the limbus attaches to the valve of the foramen ovale. Note the thick endocardial layer of the limbus and underlying myocardium separated by wide connective tissue bands. Movat x1.25. (c) A higher magnification of the boxed portion of the limbus in panel b characterized by a thickened endocardial surface rich in collagen and elastic fibers. Connective tissue bands are seen separating myocyte bundles. Movat x4.
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Figure 5 Longitudinal section of the foramen ovale and atrial septum from a heart with closed foramen ovale. The left endocardial surface of the valve is shown by the arrow. Note the slightly thickened left endocardial surface (arrow) compared to the right side. RA = right atrium.
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