US Patent 7007396 Replacement heart valve sizing device

A heart valve sizing system featuring a lumen advanceable in vasculature, an inside caliper device at the distal end of the lumen, and a readout for reading the dimension gauged by the inside caliper device. In the preferred embodiment, the inside caliper device includes a four bar linkage with first and second opposing pivot points and third and fourth opposing pivot points and a push rod connected to the second pivot point for alternatively urging the third and fourth pivot points together when extended and urging the third and fourth pivot points apart when retracted to gauge the inside dimension of the vasculature.