In Reply to: Case 0400_04 -- The Safety of Pulmonary Angiography in Patients with Severe Pulmonary Hypertension posted by Editor on April 04, 2000 at 17:06:53:
Interesting. In my fellowship I was taught that the cutoff was 2/3 of systemic pressure, and I have used that throughout my career without a problem. I did recently violate the 2/3 rule without a problem, but one case a series does not make.
You raise some very interesting questions. The cutoffs come from ancient data, published before the availablity of nonionic or (maybe more importantly) low-osmolar contrast materials. I am not aware of any large series that addresses your question. Perhaps someone out there is better read than I?