Non-thrombogenic devices for treating edema
The invention provides intravascular devices for treating certain medical conditions such as edema without causing thrombosis. The intravascular devices of the disclosure include non-thrombogenic surfaces that improve blood compatibility by reducing device-related thrombus formation and inflammatory reactions. The non-thrombogenic surfaces may include surface topographies (e.g., surface roughness) and modified chemistries (e.g., coatings and/or treatments), which prevent thrombosis by reducing local shear forces and inhibiting adhesion of blood clotting factors.
1 . A device for treating edema, the device comprising:
a catheter dimensioned for insertion into a vein, the catheter comprising:
a proximal portion;
a distal portion;
a cage attached to the distal portion of the catheter, the cage comprising:
a proximal region comprising one or more inlet openings;
a distal region comprising one or more outlet openings, said distal region being occlusive to axial blood flow;
an inner lumen; and
an exterior surface between the proximal region and the distal region and having an impeller rotatably disposed therein,
wherein the impeller is configured to pump blood through the one or more inlet openings through the cage to the one or more outlet openings to thereby create a low pressure region in the vein proximal to the one or more inlet openings, wherein the impeller pumps blood from the low pressure region through the cage to a region of higher relative pressure while mitigating recirculation,
wherein, when the impeller operates to pump blood, the inner lumen, the one or more inlet openings, and the one or more outlet openings define a fluid flow path configured to mitigate blood recirculation; and
an expandable member attached to the exterior surface of the cage between the proximal region and the distal region, wherein the expandable member surrounds a portion of the impeller and blood pumped through the cage,
wherein a portion of a surface of the expandable member comprises a non-thrombogenic surface comprising a hydrophilic material or hydrophilic coating configured to selectively bind water molecules to the exclusion of one or more blood plasma proteins thereby preventing blood clots.
2 . The device of claim 1 , wherein the non-thrombogenic surface comprises a block copolymer comprising a first polymeric block and a second polymeric block.
3 . The device of claim 2 wherein the first polymeric block comprises a hydrophilic functional group.
4 . The device of claim 3 wherein, the second polymeric block comprises a polymer repeat unit selected to enhance flexibility in the second polymeric block.
5 . The device of claim 4 wherein, the first and the second polymeric blocks are substantially immiscible and, when copolymerized, form phase separated blocks within a polymer matrix.
6 . The device of claim 1 , wherein the surface of the expandable member includes portions with the hydrophilic coating and portions without the hydrophilic coating.
7 . The device of claim 1 , wherein the hydrophilic coating comprises one selected from the group consisting of a polysaccharide, a polymer, and a hydrogel.
8 . The device of claim 7 , wherein the polymer comprises a polymer with a hydrophilic chain segment.
9 . The device of claim 7 , wherein the polysaccharide comprises a polymeric derivative of heparin.
10 . The device of claim 1 , wherein the hydrophilic coating comprises more than half of the surface of the expandable member that is exposed to blood when the expandable member is in an expanded state inside the vein.
11 . The device of claim 1 , wherein the expandable member is a balloon.
12 . The device of claim 11 , wherein upon expansion of the balloon, the balloon opposes a wall of a blood vessel and directs blood flow into one or more openings of the cage.
13 . The device of claim 11 , wherein when the catheter is operating inside the vein blood moves through the cage and out of the one or more outlet openings.
14 . The device of claim 13 , wherein upon expansion of the balloon, a distal-most portion of the balloon is aligned over the one or more outlet openings to mitigate blood recirculation.
15 . The device of claim 11 , wherein the balloon comprises a collapsed state for delivery and an expanded state for treatment wherein, in the collapsed state, a membrane of the expandable member is substantially unstressed and in the expanded state the membrane is stressed by a balloon inflation pressure.
16 . The device of claim 15 , wherein transitioning to the expanded state comprises an unfolding of the membrane.
17 . The device of claim 15 , wherein the balloon comprises a tubular segment and the expanded state comprises a radial expansion of the balloon tubular segment.
18 . The device of claim 17 , wherein the radial expansion of the tubular segment comprises an increase in the circumference of the balloon of 300% or greater.
19 . The device of claim 1 , wherein the expandable member is attached to a proximal attachment surface and a distal attachment surface of the exterior surface of the cage.
20 . The device of claim 19 , wherein the proximal attachment surface and/or the distal attachment surface comprise interstitial surfaces.
21 . The device of claim 20 , wherein the interstitial surfaces comprise a multiplicity of asperities and a plurality of interstices.
22 . The device of claim 21 , wherein attachment of the expandable member to the interstitial surfaces comprises an interpenetration of some of the material of the expandable member around the asperities of the interstitial surface and into the interstices of the interstitial surfaces.
23 . The device of claim 19 , wherein the proximal attachment surface and the distal attachment surface comprise a single tubular surface with a proximal end and a distal end.