Method and apparatus for treating venous insufficiency

#This invention relates to the treatment and correction of venous insufficiency or varicose veins, and more particularly to a minimally invasive procedure using a catheter-based system to deploy an electrode for providing radio frequency (RF) energy, microwave energy, or thermal energy to shrink a vein intraluminally to change the fluid flow dynamics and to restore the competency of the venous valve and the proper function of the vein.

#The human venous system of the lower limb consists essentially of the superficial venous system and the deep venous system with perforating veins connecting the two systems. The superficial system includes the long or great saphenous vein and the short saphenous vein. The deep venous system includes the anterior and posterior tibial veins which unite to form the popliteal vein, which in turn becomes the femoral vein when joined by the short saphenous vein.

#The venous systems contain numerous one-way valves for directing blood flow back to the heart. Venous valves are usually bicuspid valves, with each cusp forming a sack or reservoir for blood which, under pressure, forces the free surfaces of the cusps together to prevent retrograde flow of the blood and allow antegrade flow to the heart. When an incompetent valve is in the flow path of retrograde flow toward the foot, the valve is unable to close because the cusps do not form a proper seal and retrograde flow of blood cannot be stopped.

#FIG. 1 shows a cross-sectional view of a dilated vein having incompetent venous valves in a lower limb which are to be treated in accordance with the present invention;

#FIG. 2 shows a representative view of a venous section from FIG. 1 taken along lines 2-2 which is to be treated in accordance with the present invention;

#FIG. 3 shows a partial cross-sectional view of a catheter having electrodes being delivered antegrade to a venous treatment site in accordance with the present invention;

#As shown in the exemplary drawings, the invention is directed toward the intravenous treatment of veins using a catheter to deliver at least one electrode to a venous treatment site. As used herein, like reference numerals will designate similar elements in the various embodiments of the present invention to be discussed. In addition, unless otherwise noted, the term working end will refer to the direction toward the treatment site in the patient, and the term connecting end will refer to the direction away from the treatment site in the patient. The invention will be described in relation to the treatment of the venous system of the lower limbs. It is to be understood, however, that the invention is not limited thereto and may be employed intraluminally to treat veins in other areas of the body such as hemorrhoids, esophageal varices, and venous-drainage-impotence of the penis. Furthermore, although the invention will be described as using RF energy from the electrode, it is to be understood that other forms of energy such as microwaves, ultrasound, direct current, circulating heated fluid, radiant light, and lasers can be used, and that the thermal energy generated from a resistive coil or curie point element may be used as well.

#A partial cross-sectional view of a dilated vein from a lower limb having incompetent valves is shown in FIG. 1. These veins are often disposed within muscle tissue. Veins have bicuspid valves, and in a normal and competent valve, each cusp forms a sack or reservoir for blood which, under pressure, forces the free edges of the cusps together to prevent retrograde flow of the blood and allow only antegrade flow to the heart. The arrow leading out the top of the vein represents the antegrade flow of blood back to the heart. The venous valves prevent retrograde flow as blood is pushed forward through the vein lumen and back to the heart.

#When an incompetent valve encounters retrograde flow, the valve is unable to close, the cusps do not seal properly and retrograde flow of blood may occur. Incompetent valves may result from the stretching of dilated veins. As the valves fail, increased pressure is imposed on the lower veins and the lower valves of the vein, which in turn exacerbates the failure of these lower valves. A cross-sectional perspective view of a dilated vein taken along lines 2-2 of FIG. 1 is illustrated in FIG. 2. The valve cusps can experience some separation at the commissure due to the thinning and stretching of the vein wall at the cusps.