Energy based devices and methods for treatment of patent foramen ovale

#The invention generally relates to medical devices and methods. More specifically, the invention relates to energy based devices and methods for treatment of patent foramen ovale.

#Fetal blood circulation is much different than adult circulation. Because fetal blood is oxygenated by the placenta, rather than the fetal lungs, blood is generally shunted away from the lungs to the peripheral tissues through a number of vessels and foramens that remain patent (i.e., open) during fetal life and typically close shortly after birth. For example, fetal blood passes directly from the right atrium through the foramen ovale into the left atrium, and a portion of blood circulating through the pulmonary artery trunk passes through the ductus arteriosus to the aorta. This fetal circulation is shown in attached FIG. 1.

#At birth, as a newborn begins breathing, blood pressure in the left atrium rises above the pressure in the right atrium. In most newborns, a flap of tissue closes the foramen ovale and heals together. In approximately 20,000 babies born each year in the US, the flap of tissue is missing, and the hole remains open as an atrial septal defect (ASD). In a much more significant percentage of the population (estimates range from 5% to 20% of the entire population), the flap is present but does not heal together. This condition is known as a patent foramen ovale (PFO). Whenever the pressure in the right atrium rises above that in the left atrium, blood pressure can push this patent channel open, allowing blood to flow from the right atrium to the left atrium.

#FIG. 1 is a diagram of the fetal circulation;

#FIG. 2 is a diagram of a catheter apparatus according to an embodiment of the present invention, having a conductive element and closure device, the catheter passing through the inferior vena cava and right atrium and through the PFO;

#FIG. 3 is a perspective view of a catheter apparatus according to an embodiment of the present invention;

#Devices and methods of the present invention generally provide for patent foramen ovale (PFO) treatment through application or removal of energy. Methods involve advancing a catheter device to a position in the heart for treating the PFO and applying energy to (or removing energy from) tissues adjacent a PFO to substantially close the PFO acutely. Terms such as “substantially,” “acutely,” and “tissues adjacent the PFO” are defined above in the Brief Summary of the Invention. Devices of the invention generally include a catheter device having a proximal end and a distal end and at least one energy transmission member adjacent the distal end for applying energy to or removing energy from tissues adjacent the PFO.

#As mentioned above in the background section, FIG. 1 is a diagram of the fetal circulation. The foramen ovale is shown, with an arrow demonstrating that blood passes from the right atrium to the left atrium in the fetus. After birth, if the foramen ovale fails to close (thus becoming a PFO), blood may travel from the right atrium to the left atrium or vice versa, causing increased risk of stroke, migraine and possibly other adverse health conditions, as discussed above.

#With reference to FIG. 2, one embodiment of a PFO-treatment apparatus 100 may be advanced through the vasculature of a patient to a position in the heart for treating a PFO. In this embodiment, apparatus 100 includes an elongate catheter device 110 having one or more tissue apposition members 112 and one or more energy transmission members 114 at or near its distal end. Optionally, catheter device 110 may be slidably disposed over a guide member 120, such as a guide catheter (as in FIG. 1), a guidewire, or the like. Guide member 120 may include, for example, one or more expanding members 122 or other similar devices for deploying within the PFO to help appose the adjacent tissues. In some embodiments, as described further below, expanding members 122 may comprise (or be coupled with) one or more energy transmission members 114. Generally, apparatus 100 may be used to bring together tissues surrounding and/or adjacent the PFO and to transmit energy to the tissues to close the PFO.