Flow adjustable artery shunt

Claim 3

The method of claim 1 further comprising the step of monitoring the oxygen level of the blood flowing through said shunt using a sensor.

Claim 4

The method of claim 1 further comprising the step of providing an expandable bladder as part of said shunt and providing a fluid supply for filling said bladder in order to expand said bladder in the flow path defined by said shunt whereby a restriction to blood flow is provided depending on the extent to which said bladder is expanded.

Claim 5

The method of claim 2, wherein said step of monitoring the oxygen level of the blood flowing through said shunt is provided by an oximeter having a sensing probe attached to said shunt.

Claim 6

The method of claim 3, further comprising the step of periodically expanding said bladder to a predetermined state in order to inhibit the formation of pseudo-intima.

Claim 9

The apparatus of claim 6, wherein said adjustable flow restrictor comprises an inflatable bladder.

Claim 10

The apparatus of claim 7, wherein said bladder is constructed of a blood compatible material having a compliance that is greater than that of a material from which the shunt is constructed.

Claim 11

The apparatus of claim 6, wherein said adjustable flow restrictor comprises a bladder formed by a sheet of elastomeric material, a periphery of said bladder material being fastened to an inside portion of said shunt.

Claim 12

The apparatus of claim 7, wherein said restrictor control includes a pump and a reservoir of fluid, the fluid in said reservoir being communicated to and from said bladder by said pump in order to inflate said bladder thereby reducing an effective cross-section of said shunt.

Claim 13

The apparatus of claim 10, wherein said pump is controlled by said restrictor control system and is operative to fill and deflate said bladder in response to sensed oxygen saturation levels in the blood stream.

Claim 14

The apparatus of claim 11, further comprising a means for expanding said bladder periodically in order to inhibit or dislodge the formation of pseudo-intima.

Claim 15

The apparatus of claim 11, wherein said controller stores target values for said oxygen saturation levels and which are compared with said sensed oxygen saturation levels in order to determine whether an inflation state of said bladder needs to be adjusted.

Claim 16

The apparatus of claim 13, further comprising external devices for sending signals to said restrictor control system in order to change said stored target saturation levels.

Claim 19

The apparatus of claim 15, wherein said oxygen sensor comprising an oximeter.

Claim 20

The apparatus of claim 15, wherein said adjustable flow restrictor comprises an inflatable bladder for adjusting the effective size of said restrictor.

Claim 23

The apparatus of claim 18, further comprising an oxygen sensor for monitoring the oxygen saturation level in the patient's blood.

Claim 24

The apparatus of claim 19, wherein said restrictor control system is responsive to oxygen saturation levels sensed by said sensor.

Claim 25

The apparatus of claim 19, wherein said oxygen sensor comprises an oximeter.

Claim 26

The apparatus of claim 21, wherein said oximeter directly monitors the oxygen saturation level of blood flowing in said shunt.

Claim 27

The apparatus of claim 18, further comprising a means for receiving control signals from a device external to the patient's chest, said restrictor control system responding to said control signals to change the effective size of said flow restrictor.

Claim 28

The apparatus of claim 18, wherein said predetermined limits of the oxygen saturation level are stored within said restrictor control system.

Claim 29

The apparatus of claim 24, wherein said predetermined limits are changeable by control signals issued by a device external to said patient's chest.

Claim 32

For a patient having a first vascular structure and a second vascular which under normal conditions receives blood that has travelled through the first vascular structure, an apparatus for treating congenital heart defects, comprising: a) a shunt implanted within a patient's chest cavity having one end adapted to be attached to the first vascular structure of the patient and another end adapted to be attached to the second vascular structure of the patient and operative to communicate blood from the patient's second vascular structure to the patient's first vascular structure; b) an adjustable flow restrictor forming part of said shunt, said adjustable flow restrictor having at least three effective sizes; c) an oximeter including a sensor for monitoring the oxygen level of blood flowing through the patient; d) a restrictor control system responsive to said oximeter to vary the effective size of said flow restrictor said effective size of said flow restrictor being a function of the oxygen saturation level in the blood whereby a blood flow rate through said shunt is adjusted to maintain a oxygen saturation level in said blood between predetermined limits, one limit being substantially 40% and the other limit being substantially 99%; and, e) an implantable power source for providing power for said control system.

Claim 33

For a patient having a first vascular structure and a second vascular which under normal conditions receives blood that has travelled through the first vascular structure, an apparatus for treating congenital heart defects, comprising: a) a shunt implanted within a patient's chest cavity having one end adapted to be attached to the first vascular structure of the patient and another end adapted to be attached to the second vascular structure of the patient and operative to communicate blood from the patient's second vascular structure to the patient's first vascular structure; b) an adjustable flow restrictor forming part of said shunt, said adjustable flow restrictor having at least three effective sizes; c) an oximeter including a sensor for monitoring the oxygen level of blood flowing through the patient; d) a restrictor control system responsive to said oximeter to vary the effective size of said flow restrictor said effective size of said flow restrictor being a function of the oxygen saturation level in the blood whereby a blood flow rate through said shunt is adjusted to maintain a oxygen saturation level in said blood between predetermined limits, one limit being substantially 40% and the other limit being substantially 99%; and, e) an implantable power source for providing power for said control system.