Assertion: valve's risk | /r/CapableOf | remain constant
Facets:
Source sentences:
text: In addition, it was observed that the rate of embolisation appears to be decreasing with the passage of time with the pericardial valves, unlike the experience with porcine valves in the mitral position where the risk remained constant during the whole period of follow-up in spite of different schemes of long-term anticoagulation.