A biopsy assembly includes a catheter, a valve, a device having suction and pressure modes, and a loss of suction indicator. The catheter includes a proximal end, a distal end configured to capture a tissue sample, and defines a lumen therebetween. The valve defines a first port coupled to the device and a second port coupled to the proximal end of the catheter. When suction is applied to the first port, a suction path is defined from the distal end of the catheter through the lumen of the catheter and into the second port, such that the tissue sample is suctioned into the catheter. Upon loss of suction at the distal end, the pressure mode is used to define a pressure path from the first port to an open third port, expelling material therefrom. In the pressure mode, suction is maintained at the second port and catheter coupled thereto.