When the rivet is released within {HEAD ~ an artificial fistula} formed through the aorta and {TAIL ~ vena cava walls}, it expands to trap the walls between the two expanded heads 
formed through
When the rivet is released within { HEAD ~ an artificial fistula } formed through the aorta and { TAIL ~ vena cava walls } , it expands to trap the walls between the two expanded heads
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH