Response to Letter by Mazzucco et al
We thank Mazzucco and coworkers for their interesting comments. Unfortunately, we were not aware of their study1 because this was reported only in an abstract format and does not appear in the web-based scientific databases.
We do agree with them that the transesophageal echocardiograhy is the gold standard for the diagnosis of patent foramen ovale (PFO), but this is a quite invasive procedure that should be avoided in a research study. Thus, we decided to use the transcranial Doppler in our study. Interestingly, one of the authors of the letter sent by Mazzucco et al seems to agree with us, as he previously2 stated: “In the hot debate on PFO, transcranial Doppler merits a place not less than transesophageal echocardiography… It is therefore surprising that PFO assessment with transcranial Doppler is systematically neglected.” It might be of interest, however, that 2 of the subgroups of our patients with large right-to-left shunt did undergo transesophageal echocardiograhy for clinical reasons and this showed the presence of PFO.
As for genotype-phenotype relation, the hypothesis of Marzucco and coworkers that Arg141Cys mutation could be related with right-to-left shunt due to PFO is intriguing. Unfortunately, none of the patients included in our study carried the Arg141Cys mutation.