Morphological features pertinent to interventional closure of patent oval foramen

Despite the growing trend of device closure for patent ovale foramens (PFO), the morphology of these lesions is much neglected. A better understanding of the morphological aspects is needed for developing lesion-specific devices. We reviewed ten heart specimens and distinguished two forms of PFO: valve competent and valve incompetent. In the valve-competent form, the thin valve of the oval foramen adequately overlaps the firmer muscular rim of the foramen, leaving a crevice-like aperture sandwiched between the two structures. In contrast, the valve-incompetent form results from aneurysmal ballooning of the valve, or stretching of the muscular rim, creating an interatrial communication in a previously competent flap valve. Distinguishing between the two forms can help in designing and selecting the most appropriate device for implantation.