Guidewire with internal pressure sensor
The present document describes a pressure guidewire comprising: a shaft tube with a proximal section; a middle section extending from the proximal section of the shaft tube, the middle section having greater flexibility than the proximal section; an inner hypotube installed substantially within the middle section for optimal mechanical properties; a pressure sensor with a communication means routed through the middle section and the proximal section; and a sensor housing for receiving the pressure sensor. There are also described methods for joining the inner hypotube to the shaft tube.
1. A pressure guidewire comprising:
a shaft tube comprising:
a proximal section providing pushability to the pressure guidewire;
a middle section extending further distally relative to the proximal section, the middle section being cut according to a cut pattern thereby resulting in greater flexibility in the middle section than in the proximal section;
a sensor housing extending further distally relative to the middle section;
a pressure sensor communication means routed to the sensor housing through the proximal section and the middle section;
a tip pressure sensor embedded within the sensor housing and communicatively connected to the pressure sensor communication means,
an inner hypotube comprising a nickel/titanium alloy (Nitinol) or stainless steel portion installed at least completely inside the middle section, for providing stiffness and torquability, wherein the nickel/titanium alloy (Nitinol) or stainless steel portion forms a continuous cylindrical tube; and
a window through the shaft tube giving access to the inner hypotube for welding, soldering or bonding the inner hypotube within the middle section of the shaft tube.
2. The pressure guidewire of claim 1 , wherein the proximal section, the middle section and the sensor housing are made from a unitary and continuous piece of material.
3. The pressure guidewire of claim 2 , wherein the unitary and continuous piece of material comprises stainless steel.
4. The pressure guidewire of claim 1 , further comprising a small piece of material in contact with a wall of the inner hypotube and protruding within the window through the shaft tube, the small piece of material being welded to the inner hypotube.
5. The pressure guidewire of claim 4 , wherein the middle section has two ends and comprises two windows, each one of the two windows located at a respective one of the two ends of the middle section and thereby providing two areas for welding, soldering or bonding the inner hypotube within the middle section of the shaft tube.
6. The pressure guidewire of claim 1 , further comprising an adhesive or solder for joining the inner hypotube and the shaft tube.
7. The pressure guidewire of claim 1 , wherein the inner hypotube and the shaft tube are made of stainless steel, the inner hypotube comprising a distal portion having a diameter which is profiled.
8. The pressure guidewire of claim 1 , wherein the tip pressure sensor comprises an optical pressure sensor for measuring a pressure of a fluid in a blood vessel in which the pressure guidewire is inserted.
9. The pressure guidewire of claim 1 , wherein the inner hypotube is a nickel titanium alloy (nitinol) hypotube, the inner hypotube comprising a distal portion having a diameter which is profiled, thereby constituting a profiled portion.
10. The pressure guidewire of claim 9 , wherein a distal end of the profiled portion is enlarged.
11. The pressure guidewire of claim 9 , wherein the inner hypotube comprises two ends which are bonded to the shaft tube with an adhesive.
12. The pressure guidewire of claim 1 , wherein the pressure sensor communication means comprises an optical fiber.
13. The pressure guidewire of claim 1 , wherein the pressure sensor communication means is also routed within the inner hypotube.
14. The pressure guidewire of claim 1 , wherein the pressure sensor communication means has an end providing a connection to the tip pressure sensor.
15. The pressure guidewire of claim 14 , wherein the shaft tube defines a lumen, and wherein the end providing a connection to the tip pressure sensor fully occupies the lumen of the shaft tube in the proximal section.
16. The pressure guidewire of claim 1 , further comprising a band to which the pressure sensor communication means is bonded, the band being bonded to the shaft tube.
17. A pressure guidewire comprising:
a shaft tube comprising:
a proximal section providing pushability to the pressure guidewire;
a middle section extending further distally relative to the proximal section, the middle section being cut according to a cut pattern thereby resulting in greater flexibility in the middle section than in the proximal section;
a sensor housing extending further distally relative to the middle section;
a pressure sensor communication means routed to the sensor housing through the proximal section and the middle section;
a band to which the pressure sensor communication means is bonded, the band being bonded to the shaft tube; and
a tip pressure sensor embedded within the sensor housing and communicatively connected to the pressure sensor communication means,
wherein the sensor housing comprises a joining window, the band being provided at the joining window for bonding the band.
18. The pressure guidewire of claim 17 , wherein the band is a radiopaque marker band.
19. The pressure guidewire of claim 17 , wherein the band is a non radiopaque marker band.