Page 17 - Journal of Structural Heart Disease Volume 2, Issue 5

Original Research Article
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TranscatheterPFOclosuremaybeperformedwith a variety of closure devices, which are manufactured in multiple sizes. Appropriate sizing of the selected de- vice is critical to ensure adequate closure of the defect, minimize the likelihood of embolization, and avoid erosion of nearby cardiac structures. Too-large devices have been associated with erosion and an increased risk of atrial brillation [11, 12]. Conversely, devices that are too small increase the risk of incomplete closure and are at risk for embolization [13].
While there are clear guidelines for the sizing of atrial septal defect (ASD) closure devices, including use of the stop- ow technique, at this time, there is no consensus regarding the selection of closure de- vice size for PFO closure when utilizing the Amplatzer Septal Occluder “Cribriform” (ASOC) device (St. Jude Medical, SJM; St. Paul, MN, USA) for o -label closure of symptomatic PFOs. The instructions for the use of the ASOC, which is intended for ASD closure, sug- gest device size selection that maximizes device size such that the radius of the discs does not exceed the shortest distance from the defect in the septum to ei- ther the aortic root or superior vena cava (SVC) [14]. These criteria ensure that the device is large enough to cover fenestrated ASDs without impinging sur- rounding structures. Sizing balloons may be used to approximate the diameter of a PFO [15]. However, the compliant nature of the septum primum and secun- dum make this technique imprecise, and the use of a sizing balloon carries the risk of interatrial septum rupture [16]. Currently, PFO device size is selected at the discretion of experienced operators, who may rely on anatomic factors (e.g., presence of interatrial septal aneurysm, tunnel length, shunt visualization) and clinical factors (e.g., patient age, sex, and body mass index (BMI)).
This study sought to identify patient characteris- tics and echocardiographic ndings associated with size selection of the ASOC for PFO closure.
Methods
A retrospective review was performed of patients under- going percutaneous PFO closure with the ASOC device at our institution between July 2010 and December 2014. Demo- graphic and clinical characteristics were obtained. All avail- able pre- and intraprocedural echocardiography, including
transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and intracardiac echocardiography (ICE) were evaluated. Preprocedure TTE studies were reviewed for the presence of atrial septal aneurysm (ASA), which was universally de ned as atrial septal excursion >15 mm. Pre- and intra-procedural TEE and ICE were reviewed for the presence of ASA and abnormal thickening of the atrial septum (de ned as >4 mm, which is the waist length of the ASOC device used in this study). In addition, measurements of pertinent atrial anatomy were also completed, including the presence and length of any appreciable PFO tract and fossa ovalis diame- ter. All cases were performed using the ASOC self-expanding, double-disc device. The device has a double-disc design and comprises Nitinol mesh and polyester fabric. It is manufac- tured in four disc diameter sizes: 18, 25, 30, and 35 mm. The 40-mm device is not currently available in the United States. Device size selection was at the discretion of the attending interventional cardiologist.
Univariate analyses of each measured variable were per- formed to assess for association with device size selection. Fisher’s exact test was used to examine the association be- tween the individual categorical variables and the size of the nal closure device implanted. One-way analysis of variance was used for univariate analysis of continuous variables. Cate- gorical variables that were individually associated with device size were combined with pertinent clinical variables to create a total of seven hypothesized prediction scores. These scores were tested with Kruskal-Wallis H Test and Fisher’s exact test to assess the association between the proposed scoring system’s score and the size of nal closure device implanted. In addi- tion, receiver operating characteristic (ROC) curves were gen- erated to assess the sensitivity and speci city of the scores. p < 0.05 was considered signi cant. All statistical analysis was performed using STATA (StataCorp, College Station, TX, USA).
Results
A total of 36 patients underwent percutaneous PFO closure during the study period. Patient demo- graphics, pre- and intraprocedural imaging, and PFO characteristics are listed in Table 1. The indication for closure was cryptogenic stroke/transient ischemic attack in 75% of cases. Refractory hypoxemia and overwhelming deep vein thrombosis burden ac- counted for the remaining 25% of cases. Each case (100%) was successful, with complete resolution of shunt at the 6-month follow-up. No cases were com- plicated by erosion or device embolization. In three cases, a smaller device was initially delivered across the PFO before it was determined to be too small and then removed prior to the delivery and deployment of a larger device. Two of these cases resulted in chang- es from 25- to 30-mm diameter devices. One case
Journal of Structural Heart Disease, October 2016
Volume 2, Issue 5:217-223