| 摘要 |
Rotating element catheters and catheter assemblies employ clutch assemblies for preventing rotational energy from being transmitted from a motor drive unit to the catheter element under defined circumstances. The catheter assembly includes an elongate member in which there is disposed a rotatable catheter drive cable. The catheter drive cable may have an operative element, e.g., an ultrasonic transducer or an artherectomy blade, distally mounted thereon for providing diagnostic or therapeutic functions to the physician. To control the rotation of the catheter drive shaft, the clutch assembly is configured such that the catheter drive shaft is operated in a drive mode (i.e., it is allowed to rotate) and in a release mode (i.e., it is prevented from rotating). The clutch assembly can be formed from a driven member and a driver member, which cooperate with each other, such that the driven and driver members are rotatably engaged with each other before an applied torque exceeds the critical magnitude, and rotatably unengaged with each other after the applied torque exceeds the critical magnitude. This clutching function can be actuated by any of a variety of physical forces, e.g., frictionally or magnetically.
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