Lessne and Sing raise important considerations regarding the utilization of inferior vena cava (IVC) filters in the United States. A key premise of their argument concerns indications for caval filtration, and they maintain that most filters are currently placed for prophylactic reasons. The references to support this contention are nebulous, and given the huge variability of filter insertion even within similar geographic areas, we doubt that this is known. One of the references cited to support this contention is a review which further cited several studies which also do not prove the contention. In fact, one of the references in this review is from the University of Chicago (one of the author’s institution) in which prophylactic filters comprise < 20% of filters inserted. Incidentally, this same study also reported an 87% retrieval rate showing that with good follow-up, the contention that “optional filters are infrequently removed” is inaccurate. The use of prophylactic filters appears to be decreasing, even in bariatric patients and in trauma centers where prophylactic filter placement is expected to be high., A final complicating factor of this topic is the definition of prophylactic. Does this mean absence of DVT and pulmonary embolism (PE), or DVT but no PE? We favor the former definition, but this is not universal in the published literature.