Surgery – Instruments – Blood vessel – duct or teat cutter – scrapper or abrader
Patent
1997-09-29
1999-02-23
Dawson, Glenn K.
Surgery
Instruments
Blood vessel, duct or teat cutter, scrapper or abrader
606180, 606170, A61B 1722, A61B 1732, A61B 1714
Patent
active
058738827
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a catheter of the type known as a rotary catheter.
A catheter of this kind is used in particular for treating occlusive diseases of the arteries by dislodging and breaking up stenoses and blood clots. It is introduced into the artery or vein and is advanced as far as the stenosed area which is to be treated. A cutting tool which can be driven in rotation is arranged at its front or leading end.
DISCUSSION OF THE BACKGROUND
The present invention utilizes a cutting edge which extends at least approximately in the axial direction. It is also possible to arrange straight cutting edges inclined with respect to the axial direction or to have one of the cutting edges running in an undulating configuration in the axial direction relative to a cylindrical surface. Since the cutting edges of the rotor may be knife edges, this allows the rotor, even before the shearing action is started, to dislodge from the vessel wall any deposits which are protruding or bulging into the shearing slot. The rotor is at least partially tapered in the direction of its front end and has at its front means to break up loose and solid deposits such as blood clots. This means may include a front face and two adjoining beveled surfaces lying opposite each other while the front face has on a circumference horn-like forwardly extending projections. This ensures that the rotor forces its way through the blood vessel in particular at stenosed or blocked sites. The stator and rotor may be made of metal although other materials such as suitable plastics may be used.
A guide wire which is preferably independent of the catheter extends therethrough. This facilitates the introduction of the catheter into the artery or vein by way of the guide wire which has already been introduced. The stator is connected to the tubular sheath serving as a catheter tube. It is also possible to fasten the stator in a movable manner at the tip or leading edge of the tubular sheath.
A further known catheter, the one from E-PB1-0,267,539, has as its cutting tool a substantially elliptical milling cutter which is provided with abrasive material on its surface and is driven at a speed of up to 160,000 rpm. The milling cutter is connected via a flexible drive shaft to a rotary drive mechanism which is arranged at the other end of the catheter. The drive shaft runs through a tubular sheath which serves as a catheter tube. A guide wire extending right through the drive shaft is introduced into the artery or vein before introduction of the catheter and is pushed forwards.
In this known rotary catheter, it is not possible to exclude the risk of the vessel wall being damaged, particularly at a curve, and in some cases even being drilled through.
Another known rotary catheter has a cutting tool which has two stripping blades and which is driven at a speed of 750 rpm. In this catheter, there is a risk that the stripping blades may, particularly at the relatively slow circumferential speed, pinch or tear or get caught in the vessel wall.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of providing a catheter which is of the type mentioned at the outset and which on the one hand ensures that abnormal deposits in the blood vessels of humans are dislodged cleanly, and on the other hand makes damage to the vessel wall highly improbable.
The catheter according to the invention ensures that only deposits which are protruding and which come between the cutting edges can be caught and dislodged. The possibility of the vessel wall being damaged by the cutting tool is virtually ruled out here. Moreover, the risk of the cutting tool of such a catheter tearing and pinching the vessel wall is in practice eliminated by the shearing action in conjunction with the opposite cutting edge.
In a preferred embodiment the rotor attacks the deposits radially. This ensures that it is not possible, for example in the area of curves, to drill straight into the vessel wall.
Additional safety against damage to the vessel wal
REFERENCES:
patent: 4857046 (1989-08-01), Stevens
patent: 5112299 (1992-05-01), Pascaloff
patent: 5269751 (1993-12-01), Kaliman
patent: 5383884 (1995-01-01), Summers
The Practice of Interventional Cardiology Chapter 13, Percutaneous Transluminal Coronary Rotary Ablation with the Rotablator, pp. 141-147, Michel E. Bertrand, et al.
The Practice of Interventional Cardiology Chapter 14, Coronary Atherectomy with the TEC Device, Michael H. Sketch, Jr., et al., pp. 149-155.
The Practice of Interventional Cardiology Chapter 15, Directional Coronary Atherctomy, Matthew R. Selmon, et al., pp. 157-169.
The Practice of Interventional Cardiology Chapter 16, Percutaneous Rotational Thrombectomy: An Alternative Approach to Thrombolysis, pp. 171-176, Timothy A. Dewhurst, et al.
Mohr Helmuth
Straub Immanuel
Dawson Glenn K.
Straub Medical AG
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