Force-based heart valve sizer

摘要

A valve sizer for determining an appropriate replacement valve size when performing a heart valve replacement procedure is provided. In one version the valve sizer has a hollow shaft with proximal and distal ends. A movable sizing element couples to the distal end of the shaft and is radially expandable between first, contracted and second, expanded positions. An actuator assembly on a handle includes an actuator coupled to a clutch member via a ball-spring-detent clutch. A rod extends through the shaft and maintains a fixed distance between the handle and a distal hub in the sizing element. Movement of the actuator causes axial movement of the shaft, thereby causing radial expansion of sizing petals relative to the hub. The clutch slips when a predetermined reaction force from the surrounding valve annulus is met by the petals.

主权项

1. A heart valve sizer for determining an appropriate replacement prosthetic heart valve size when performing a valve replacement procedure comprising:
a proximal handle having an actuator comprising an actuator ring mounted for rotation about the handle; a shaft extending distally from the proximal handle and having a movable member and a stationary member; a sizing element coupled to the distal end of the shaft, the sizing element having a hub and a plurality of petals each radially movable between a first retracted position and a second expanded position, the hub being fixed to the stationary member in the shaft and the petals being connected to expand radially upon displacement of the movable member in the shaft; and a clutch mechanism in the proximal handle connected between the actuator and the movable member in the shaft so as to transmit movement forces therebetween, the clutch mechanism including a clutch ring rotatably coupled to the actuator ring via a plurality of bearings movable with the clutch ring and biased by springs into detents in the actuator ring, wherein rotation of the actuator ring causes displacement of the movable member via the clutch ring and consequently outward radial expansion of the petals in the sizing element into contact with a surrounding heart valve annulus, wherein the clutch mechanism slips at a predetermined desired reaction force imparted by the heart valve annulus against further outward radial expansion of the petals.