Direct Visualization Of The Fossa Ovalis For Transeptal Puncture: In Vivo Evaluation Of The Iris Catheter In A Porcine Model

Introduction: Transeptal puncture is required for many interventional procedures but has a serious complication rate of ~1%. The primary risk of the procedure is related to mis-identification of the interatrial septum resulting in inadvertant puncture of the aorta or the atrial wall into the pericardium. We have investigated the utility of a catheter that allows direct visualization of the fossa ovalis to correctly position the transseptal needle at the interatrial septum. Methods: This study included 6 swine. The IRIS catheter (Voyage Medical, Campbell, CA) enables direct visualization using a cone-shaped hood into which saline is infused to exclude blood. In 4/6 animals, intracardiac echocardiography was used to visualize, but not guide, the transeptal puncture; there was no visible tenting of the septum. After transeptal puncture was performed the IRIS catheter was used to directly visualize and cannulate the puncture sites. Results: In 5 animals, transeptal puncture was successfully performed repeatedly (2–4 punctures/animal), and a .035 guidwire passed into the left atrium. IRIS could also guide cannulation of previous puncture in these animals. In 1 animal, visualization could not be performed because the atrial septum was lacerated during an attempt at left atrial visualization via a patent foramen ovale. Pericardial effusion was only observed in this latter animal on post-mortem exam. IRIS visualization of the atrial septum correlated well with the pathological specimen (see Figure ). Conclusion: The IRIS catheter allows direct in vivo visualization of the interatrial septum to guide de novo transeptal puncture or cannulation of previous punctures. Top: A cascade of in vivo IRIS images of transeptal puncture holes (arrows) and a PFO Bottom: Corresponding post mortem speciman