Apparatus and method for testing prosthetic heart valves
First Claim
1. Apparatus adapt to test prosthetic heart valves under flow conditions of a fluid through a flow channel simulating a circulatory system into which the valves are to be used, comprising:
- an intake chamber for receiving said fluid having a fluid inlet, a first intake orifice and a second intake orifice;
a first test chamber in fluid communication with said first intake orifice and defining a first test portion of said flow channel, said first test chamber including a first mounting fixture moveably received therein and having a first cavity adapted for securing a first heart valve whereby the first heart valve may be selectively moved from a passive position out of the flow channel and into a first test position interposed in said flow channel, said first mounting fixture having first dynamic sealing means for maintaining a fluid seal with said first test chamber as the first mounting fixture moves therein;
a second test chamber in fluid communication with said second intake orifice and defining a second test portion of said flow channel, said second test chamber including a second mounting fixture moveably received therein and having a second cavity adapted for securing a second heart valve whereby the second heart valve may be selectively moved from a passive position out of the flow channel and into a second test position in said flow channel, said second mounting fixture having first dynamic sealing means for maintaining a fluid seal with said second test chamber as the second mounting fixture moves therein;
a restriction chamber defining a restrictive portion of said flow channel and having first and second restriction chamber flow orifices, said restriction chamber including restriction means for selectively varying resistance to the flow of the fluid through the restriction chamber;
first conduit means for interconnecting said first restriction chamber flow orifice and said first test chamber for fluid flow therebetween and defining a first conduit portion of said flow channel;
second conduit means for interconnecting said second restriction chamber flow orifices and said second test chamber for fluid flow therebetween and defining a second conduit portion of said flow channel;
first fluid pressure compensation means in fluid communication with the flow channel in said first conduit portion for selectively applying pressure to fluid therein and having a first compensation reservoir adapted to receive excess fluid in the flow channel;
second fluid pressure compensation means in fluid communication with the flow channel in said second conduit portion for selectively applying pressure to fluid therein and having a second compensation reservoir adapted to receive excess fluid in the flow channel; and
pump means for cyclically pumping fluid alternately by a power stroke and a recovery stroke, said fluid being pumped during the power stroke through said fluid inlet towards said first and second test chambers whereby one of said first and second heart valves passes the fluid therethrough while the other one of said first and second heart valves resists fluid flow, fluid being pumped during the power stroke accumulating under pressure in said first and second compensation reservoirs, and during the recovery stroke whereby said one of the heart valves closes and the other one of the heart valves opens so that said first and second fluid pressure compliance means force fluid through the other one of heart valve back into said intake chamber, said restriction means being selectively adjustable to permit flow of a volume of fluid over a time period of one pump cycle which volume is equal to the volume of fluid displaced by the power stroke of the pump;
said intake chamber, said first and second test chambers, said restriction chamber, and said first and second conduit means forming the flow channel containing fluid for circulation therethrough.
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Accused Products
Abstract
An apparatus and method for testing prosthetic heart valves prior to implant in the human body provides a test chamber having a flow channel therethrough and a passageway which receives a mounting fixture for a heart valve. The test chamber is used in a mock circulatory loop with the flow channel being in the loop. Preferably, the test chamber has a transverse passageway that intersects the flow channel, and the mounting fixture advances completely through the test chamber from an insertion location to a disconnect location while a dynamic seal is maintained. Two such test chambers may be used in a mock loop, and the loop is configured with an intake chamber fluidly interconnecting one side of each test chamber, and a restriction chamber fluidly interconnecting the other sides of the test chambers. The restriction chamber is variable, and pressure compensation is provided between each of test chambers and the restriction chamber. A pump cyclically drives a fluid through the loop, and flow meters and pressure sensors monitor the test. A data processor monitors and processes the flow data and controls the pump to create a desired flow waveform. The test can also be visually and optically monitored.
63 Citations
42 Claims
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1. Apparatus adapt to test prosthetic heart valves under flow conditions of a fluid through a flow channel simulating a circulatory system into which the valves are to be used, comprising:
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an intake chamber for receiving said fluid having a fluid inlet, a first intake orifice and a second intake orifice; a first test chamber in fluid communication with said first intake orifice and defining a first test portion of said flow channel, said first test chamber including a first mounting fixture moveably received therein and having a first cavity adapted for securing a first heart valve whereby the first heart valve may be selectively moved from a passive position out of the flow channel and into a first test position interposed in said flow channel, said first mounting fixture having first dynamic sealing means for maintaining a fluid seal with said first test chamber as the first mounting fixture moves therein; a second test chamber in fluid communication with said second intake orifice and defining a second test portion of said flow channel, said second test chamber including a second mounting fixture moveably received therein and having a second cavity adapted for securing a second heart valve whereby the second heart valve may be selectively moved from a passive position out of the flow channel and into a second test position in said flow channel, said second mounting fixture having first dynamic sealing means for maintaining a fluid seal with said second test chamber as the second mounting fixture moves therein; a restriction chamber defining a restrictive portion of said flow channel and having first and second restriction chamber flow orifices, said restriction chamber including restriction means for selectively varying resistance to the flow of the fluid through the restriction chamber; first conduit means for interconnecting said first restriction chamber flow orifice and said first test chamber for fluid flow therebetween and defining a first conduit portion of said flow channel; second conduit means for interconnecting said second restriction chamber flow orifices and said second test chamber for fluid flow therebetween and defining a second conduit portion of said flow channel; first fluid pressure compensation means in fluid communication with the flow channel in said first conduit portion for selectively applying pressure to fluid therein and having a first compensation reservoir adapted to receive excess fluid in the flow channel; second fluid pressure compensation means in fluid communication with the flow channel in said second conduit portion for selectively applying pressure to fluid therein and having a second compensation reservoir adapted to receive excess fluid in the flow channel; and pump means for cyclically pumping fluid alternately by a power stroke and a recovery stroke, said fluid being pumped during the power stroke through said fluid inlet towards said first and second test chambers whereby one of said first and second heart valves passes the fluid therethrough while the other one of said first and second heart valves resists fluid flow, fluid being pumped during the power stroke accumulating under pressure in said first and second compensation reservoirs, and during the recovery stroke whereby said one of the heart valves closes and the other one of the heart valves opens so that said first and second fluid pressure compliance means force fluid through the other one of heart valve back into said intake chamber, said restriction means being selectively adjustable to permit flow of a volume of fluid over a time period of one pump cycle which volume is equal to the volume of fluid displaced by the power stroke of the pump; said intake chamber, said first and second test chambers, said restriction chamber, and said first and second conduit means forming the flow channel containing fluid for circulation therethrough. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. In apparatus for testing the operation of a prosthetic heart valve wherein the apparatus includes a flow channel simulating the circulatory system into which the valve is to be implemented, the improvement comprising:
- a test chamber having a flow channel region extending between a first orifice and a second orifice and adapted for insertion in fluid communication into the flow channel of said apparatus for conducting flow of fluid from one orifice to the other orifice, said test chamber having a passageway therethrough intersecting said flow channel region;
a mounting fixture sized for mated engagement in said passageway whereby the mounting fixture may be inserted into an entry opening of said passageway on one side of the test chamber, slideably moved through the passageway and removed from the passageway at an exit opening on another side of said test chamber, said mounting fixture having a cavity extending therethrough and provided with mounting means for mounting and supporting a heart valve to be tested whereby said cavity may be moved into fluid communication with said flow channel region and said heart valve oriented in the flow of fluid through the test chamber; and
dynamic sealing means on said mounting fixture for maintaining fluid seal as the mounting fixture is moved through the passageway. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
- a test chamber having a flow channel region extending between a first orifice and a second orifice and adapted for insertion in fluid communication into the flow channel of said apparatus for conducting flow of fluid from one orifice to the other orifice, said test chamber having a passageway therethrough intersecting said flow channel region;
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33. A method for testing prosthetic heart valves by placing a heart valve in a simulated circulatory system defining a flow channel and having adjustable fluid flow rates and pressure, comprising the steps of:
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providing at least one test chamber in said flow channel, said test chamber having oppostie test chamber flow orifices whereby fluid may flow from one orifice to the other orifice as part of the flow channel, said test chamber including a first transverse passageway completely therethrough and intersecting said flow channel; providing a first mounting fixture having a first cavity sized to mount a first heart valve for orientation in the flow channel; mounting said first heart valve in said first cavity and advancing said first mounting fixture through said first passageway from a passive position wherein said first heart valve is not in said flow channel, through an entryway into the first passageway to a test position wherein the first heart valve is oriented in the flow channel, and to a disconnect location for removal of the first mounting fixture from said first passageway opposite said entryway; maintaining a dynamic seal between said first test chamber and said first mounting fixture during the movement of the first mounting fixture through the first passageway; measuring the flow rate of fluid through the flow channel adjacent the heart valve to generate flow rate data; and measuring the pressure of the fluid upstream and downstream of the heart valve to generate channel pressure data. - View Dependent Claims (34, 35, 36, 37, 38)
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39. A method for testing a prosthetic heart valve oriented at a test location in a simulated circulatory system having a flow channel containing test fluid for circulation, a selectively adjustable fluid restriction element operative to selectively resist flow of fluid through the flow channel, a compensation chamber having a compensation reservoir in fluid communication with the flow channel downstream of the heart valve and a pressure means adapted to selectively and adjustably apply pressure to fluid in the flow channel, and a pump having a selectively adjustable period, amplitude and duty cycle for driving the fluid in a selected waveform through the flow channel, comprising the steps of:
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providing data processing means for automatically monitoring fluid conditions in the flow channel and adjusting the pressure applied by the fluid restriction element and controlling the waveform of the pump; loading said data processing means with data corresponding to the desired waveform of fluid flow through the flow channel; setting an initial fluid resistance applied by said fluid restriction element; activating said pump through the desired waveform according to its duty cycle; measuring the flow rate of fluid through the flow channel adjacent the heart valve to generate flow rate data; measuring the pressure of the fluid upstream and downstream of the heart valve to generate channel pressure data; inputting said flow rate data and channel pressure data into said data processing means and calculating the fluid flow and pressure waveform through said flow channel; comparing the fluid flow and pressure waveform and the desired waveform to determine waveform error; and adjusting the resistance of the fluid restriction element to proportionally reduce the waveform error by interative processing of the flow rate and channel pressure data to tune the fluid flow and pressure waveform on successive cycles of the pump until the fluid flow and pressure waveform models the desired waveform within predefined error range. - View Dependent Claims (40, 41, 42)
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Specification