Aortic shunt with spinal perfusion and cooling device

Details Aortic shunt with spinal perfusion and cooling device Aortic shunt with spinal perfusion and cooling device

1999-11-16

2003-03-11

Sykes, Angela D. (Department: 3762)

Surgery

Devices transferring fluids from within one area of body to...

With flow control means

C604S096010, C623S001240, C606S195000, C128S898000

Reexamination Certificate

active

06530894

ABSTRACT:

FIELD OF THE INVENTION
The present invention generally relates to medical devices for perfusing a patient's spinal vasculature during thoracoabdominal surgery. More particularly, the devices comprise an aortic shunt which is releasably mounted to a catheter at a first end of the devices and to a tubular member having tubular branches adapted for insertion into spinal arteries at a second end. The shunt also includes an expandable occluder for occluding the aortic lumen and a valve for controlling fluid or blood flow to the spinal arteries. A cooler may be included for providing hypothermic perfusion to the spinal cord.
BACKGROUND OF THE INVENTION
Thoracoabdominal surgeries, including abdominal aortic aneurysm repair, aortic dissection repair, and aortic thrombectomy, are associated with substantial neurologic morbidity. During abdominal aortic aneurysm repair, for example, an arterial clamp is placed across the aorta for total occlusion and the abdominal aorta is incised or transected for repair. The iliac, the superior mesenteric, and the spinal arteries are often ligated at their origins from the aorta. As a result, spinal cord ischemia can occur in up to 30% of patients. Spinal ischemia is caused partly by lack of blood flow to the spinal cord during aortic clamping, and partly by embolization from the aorta into the spinal arteries.
To reduce the incidence of peri-operative spinal ischemia, several devices were developed to maintain perfusion to the spinal arteries during thoracoabdominal surgeries. Moses describes an internal aortic shunt which perfuses the distal aorta. However, the shunt fails to specifically perfuse the spinal arteries. An intravascular device was described in Rom et al., U.S. Pat. No. 5,746,709, incorporated herein by reference, which involves an intra-aortic pump. Disadvantages associated with this device are that (1) puncturing of the aorta is required for inserting an occluder, (2) arterial clamping is required, which carries the risk of thromboembolism, (
3)
the aorta needs to be incised for inserting catheters into the spinal arteries.
Rayhanabad developed a single component device for spinal perfusion during aortic surgeries. However, the device cannot be inserted prior to severing of the aorta and therefore failed to eliminate the need for aortic cross clamping and puncture. Khorasani describes an external shunting system with branches to perfuse the spinal arteries through the aorta. However, this system still requires aortic clamping and perforation.
According, there is a need for devices and methods which provide perfusion to spinal arteries during thoracoabdominal surgeries, and reduce neurologic complication by obviating the need for aortic clamping and puncture.
SUMMARY OF THE INVENTION
The present invention provides intravascular devices which include an intra-aortic and extra-aortic component for perfusing the spinal arteries during thoracoabdominal surgeries. In a first embodiment, the intra-aortic component comprises a catheter having a proximal end, a distal end, and shunt releasably mounted on the distal end of the catheter. The shunt comprises a tubular member having a lumen communicating with a first end and a second end. An expandable occluder, such as an inflatable balloon, is disposed about the tubular member of the shunt and is adapted to occlude the aortic lumen. The shunt also includes a valve distal to the occluder for controlling blood or fluid flow through the lumen of the shunt.
The extra-aortic component comprises a second tubular member having a lumen communicating with a first end and a second end. The first end is adapted for attachment to the second end of the shunt. In certain embodiments, the second end of the shunt is tapered to facilitate its attachment to the second tubular member. The second end of the second tubular member is attached to a plurality of tubular branches. Each tubular branch has a lumen communicating with the lumen of the second tubular member, and a distal opening adapted to enter a spinal or intercostal artery.
In another embodiment, a manometer is included in the first end and/or second end of the shunt for monitoring pressure upstream or downstream the shunt. In certain embodiments, a manometer is included in the second tubular member or in each tubular branch for monitoring perfusion pressure to the spinal arteries.
In another embodiment, a cooler, or heat exchanger, is attached to the second tubular member for providing hypothermic perfusion to the spinal cord. Perfusing the spinal cord at below the normal body temperature, typically at 34° C., is known to protect the spinal cord from ischemic insult. In certain embodiments, an expandable occluder is mounted on a distal region of each tubular member for preventing back leak of blood during perfusion of the spinal arteries. A valve may be included in the distal region of the tubular branch for controlling blood flow through the spinal artery.
Using the devices described above for perfusing the spinal vasculature during thoracoabdominal surgeries, the catheter, having the shunt attached at its distal end, is inserted into the aorta through a peripheral artery, such as the subclavian or the femoral artery. Prior to insertion, the occluder is placed in a collapsed state, and the valve is turned off to allow no flow through the lumen of the shunt. After the shunt is positioned proximal, i.e., upstream, to the region of interest in the aorta, the occluder is expanded to occlude the aortic lumen, thereby obviating the need for aortic cross clamping. The shunt is then released from the catheter. Incision(s) downstream of the occluder are made for aortic repair. The first end of the second tubular member is attached to the second end of the shunt. The distal end of each tubular branch is inserted into the spinal arteries, and sealed from back leakage of blood. The valve on the shunt is then opened to allow blood flow through each tubular branch to perfuse the spinal vasculature.
In another method, prior to perfusing the spinal arteries, the blood is cooled to below body temperature by a cooler attached to the second tubular member. The tubular branches can also be inserted into the iliac, the mesenteric, or the renal arteries to perfuse the bowel or the kidney in addition to perfusing the spinal cord. Pressures in the proximal aorta and the tubular branches can be measured by manometers included in the shunt and/or the tubular branches. The valves in the shunt and/or the tubular branches can be partially opened or closed to maintain adequate perfusion to the spinal vasculature.
It will be understood that there are several advantages in using the intravascular devices and methods disclosed herein for spinal perfusion during thoracoabdominal surgeries. For example, the devices (1) provide perfusion to the spinal arteries throughout the entire vascular procedure, (2) provide hypothermic perfusion to the spinal cord, (3) reduce the risk of embolization by obviating the need for aortic corss-clamping prior to severing the aorta, (4) can be used to perfuse renal and/or mesenteric arteries, (5) do not require a pump, and (
6)
do not require systemic heparinization, thereby avoiding the risk of systemic hemorrhage.


REFERENCES:
patent: 4398907 (1983-08-01), Crais
patent: 4586919 (1986-05-01), Taheri
patent: 4592754 (1986-06-01), Gupte et al.
patent: 4712551 (1987-12-01), Rayhanabad
patent: 4712661 (1987-12-01), Rayhanabad
patent: 4979937 (1990-12-01), Khorasani
patent: 5453084 (1995-09-01), Moses
patent: 5545135 (1996-08-01), Iacob et al.
patent: 5746709 (1998-05-01), Rom et al.
patent: 5957963 (1998-05-01), Dobak, III
patent: 5843050 (1998-12-01), Jones et al.
patent: 6139517 (2000-10-01), Macoviak et al.

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