The above letter was referred to Drs. Jacobs, Maraj, and Kotler, who reply in this manner:
We wish to respond to Dr. Cheng's letter with the following comments:
First, in the review article that was referenced in our case report, 1 we previously reported a patent foramen ovale (PFO) frequency range of 5–38% in controls. Certainly a frequency of 20% or 27.3% falls in this range.
Second, a persistent Eustachian valve is a common finding and may indeed cause right-to-left shunting across the PFO, due to streaming.
Third, the patient in our case report was equally hypoxic in the supine and standing positions and had a markedly positive bubble-contrast echocardiographic test for PFO in both these positions. This was independent of respiratory maneuvers. Although platypnea-orthodeoxia may be a rare cause of persistent right-to-left shunting across a PFO, it does not appear to have been significant in our patient.
Fourth, it is difficult to prove that a patient with paradoxical embolism does not have transient pulmonary hypertension induced by pulmonary embolism.
Fifth, at the time we wrote this case report, a transcatheter closure device was considered a “humanita-rian-use device,” which limited its use to facilities that had established an institutional review board (IRB) to supervise the clinical testing of the device. The device could be used only after an IRB had approved its use to treat a specific disease. The trans-catheter closure device has recently been approved by the FDA.