Randomized study comparing mechanical with electronic 2-dimensional intracardiac ultrasound monitoring (MEDIUM) during percutaneous closure of patent foramen ovale in adult patients with cryptogenic stroke

Background: Previous studies have shown that mechanical and electronic intracardiac echocardiography (ICE) improves ultrasound monitoring during transcatheter patent foramen ovale (PFO) interventional closure. Objectives: This study sought to compare the procedural data, clinical imaging quality, and effectiveness PFO closure by using two different ICE monitoring modalities. Methods: Patients referred for PFO closure (n = 82) were randomly assigned to mechanical (group 1) or electronic (group 2) ICE monitoring of Amplatzer device implantation. The digital ICE images were evaluated offline by means of absolute visual grading analysis score (VGAS(abs)), and the residual shunting at follow-up were assessed by means of contrast echocardiographic studies, all blinded regarding the ICE closure monitoring modality. Results: The two groups were comparable with respect to clinical baseline characteristics, intracardiac fossa ovalis measurements, and procedural data (fluoroscopy time, procedure time and measurement of the amount of radiation that the patients absorbed). The total VGAS(abs) ranked the mechanical clinical images in a higher order than the electronic ones (3.78 +/- 0.09 vs 3.58 +/- 0.12, P = 0.005); additionally, three patients (7.3%) of group 2 needed to cross over to mechanical ICE monitoring because a right-convex atrial septal aneurysm configured itself incompletely. No differences in rates of residual shunting were observed at 12 months follow-up between the two groups (97.5% vs 94.7%, P = 0.951). Conclusions: Electronic monitoring of PFO closure performed a less diagnostic impact than the mechanical one while maintaining comparable procedural data and clinical outcome. These results represent an important step in validating these new intracardiac ultrasound imaging modalities.