Catheter Closure of Perforated Secundum Atrial Septal Defect Under Intracardiac Echocardiographic Guidance Using a Single Amplat

Transcatheter closure of single secundum atrial septal defects (ASDs) or patent foramen ovale (PFO) is a well-accepted alternative to surgical repair in selected patients,¹ and intracardiac echocardiography (ICE) has been demonstrated to be superior to conventional transesophageal echocardiography (TEE) monitoring for guiding device placement.² On the contrary, perforated ASDs³ still remain a challenge for both sonographers and interventionists. This morphological variation has been successfully treated by percutaneous placement of two Amplatzer septal occluder devices^4,5 (AGA Medical Corporation, Golden Valley, Minnesota) or a single one after performing balloon atrial septostomy.⁶ In such cases, an ICE-guided central approach through the flap valve may warrant an improved cosmetic septal reconstruction using only a single Amplatzer PFO or Cribriform occluder device; however, no systematic assessment of its feasibility and effectiveness has been reported. Therefore, the purpose of the present study is to explore the ability to evaluate fossa ovalis size and geometry by ICE in order to attempt transcatheter closure of perforated ASDs using a single Amplatzer PFO or Cribriform occluder device. Methods Study patients. Between July 2000 and July 2003, 207 consecutive eligible patients with hemodynamically significant ASDs (28 males, 60 females) or symptomatic PFOs, with or without ASA (62 males, 57 females), underwent transcatheter closure using the Amplatzer device and ICE as the primary imaging tool both for choosing the proper device size and monitoring each stage of the procedure. Among these, 24 patients (5 males, 19 females) had TEE diagnosis of perforated ASDs; these 24 patients represent the working group of the study. Intracardiac echocardiography. ICE was performed by the same interventional team using a commercially available 9 Fr 9 MHz Ultra ICE catheter-based ultrasound transducer (EP Technologies, Boston Scientific Corporation, San Jose, California), as previously described.7 In order to obtain an adequate spatial architecture of the atrial septum and to understand the relationship between the defects and the neighboring structures, two standardized sections were used: the transverse section on the aortic valve plane and the longitudinal section on the four-chamber plane. This latter view was also used to monitor each stage of the device deployment. The dimensions of both the entire atrial septum and fossa ovalis on these two orthogonal planes, as well as the distance between the eccentric guidewire passage and the more adjacent rim of the fossa ovalis (GW-R) on the longitudinal plane, were measured using end diastolic frames. Moreover, by assuming the fossa ovalis shape to be an ideal ellipse, the following data were calculated: 1) the eccentricity (e = ? a2 - b2 , where e is a number that expresses the shape of the ellipse, and a and b are the semi-major and semi-minor axes of the ellipse, respectively); 2) the periapsis distance (rp = a(1-e), where rp is the smallest radial distance of an ellipse, as measured from a focus on its major axis]; and 3) the diameter of the ideal-derived circle (d = 2? c2 + p2 where d is the diameter of the ideal-derived circle, whereas c and p are the foci half-distance and the semi-latus rectum distance of the elliptical fossa ovalis, respectively), whose circumference and area approximately equal the elliptical perimeter and area of any given fossa ovalis, as previously described.⁸Closure technique and follow-up. All procedures were carried out under local anesthesia with fluoroscopic and continuous ICE monitoring. Figures 1 and 2 demonstrate the fluoroscopic and ICE steps of our “double guidewire” transcatheter closure technique, respectively. Briefly, two 0.035 inch -260 cm guidewires were introduced via the right femoral vein through a 9 Fr sheath, crossing two separate defects (Figure 1, A and B) by means of a 5 Fr Super TorquePlus MP A2 catheter (Cordis Europa, LJ Roden, The Netherlands). For ICE, the Ultra ICE catheter was inserted via a 55° precurved 8.5 Fr venous sheath (Convoy, EP Technologies, Boston Scientific Corporation) from the left femoral vein, and advanced through the inferior vena cava into the right atrium, in order to obtain the aforementioned two orthogonal planes (Figure 2, A and B). Finally, the Amplatzer PFO or Cribriform occluder device size was chosen on the criterion of the complete coverage of the fossa ovalis and the delivery system was advanced through the guidewire, crossing the perforated ASDs in the central position. From a practical point of view, an implant right atrial disk diameter to d value ratio of >= 1:1 was recommended for implantation, postulating a higher closure rate with oversized devices. Follow-up included pre-discharged contrast transthoracic echocardiography (TTE), 3 months TEE, and 12 months TTE or TEE when a residual shunt (classified according to Boutin et al.9 criteria) was detected at 3 months TEE. Statistical analysis. Data were expressed as mean value SD, and in percentages where appropriate. The SPSS PC 11.0 (SPSS Inc.,Chicago, Illinois) software package for Windows was used for statistical analysis. The measured GW-R distances were compared separately with the rp ICE-derived values by means of the Bland-Altman plot.¹⁰ Results Out of 207 patients, the 24 who underwent transcatheter closure of interatrial communications (11.6%) had a TEE diagnosis of perforated ASD. Demographic and procedural data are reported in Table 1, whereas the ICE measurements and their geometric-derived calculi are listed in Table 2. The greatest axes across the atrial septum and the fossa ovalis were always found along their longitudinal plane (65.6 mm and 32.3 mm, respectively), whereas the smallest axes were always found along their transverse plane (40.4 mm and 26.5 mm, respectively). The GW-R distance, as measured by ICE, was 7.03 ± 1.56 mm (range 4.5–9.9 mm), whereas the rp derived value was 7.15 ± 1.79 mm (range 4.14–10.4 mm), showing a sufficiently close agreement between these two measurement methods (Table 3). Defining an implant right atrial disk diameter to a d value ratio of >= 1:1 to be mandatory for adequate coverage of the fossa ovalis, two Amplatzer PFO occluders 25 mm, 9 Amplatzer PFO occluders 35 mm, and 13 Amplatzer Cribriform occluders (four 25 mm and nine 35 mm) were implanted successfully. In 8 patients, an implant right atrial disk diameter to a d value ratio = 1 was used, whereas in the remaining 16 patients, the ratio was > 1.1:1. During follow-up (31.4 ± 7.2 months), complete closure by contrast echo-color Doppler occurred in 16/24 (67%) patients after 24 hours, 19/24 (79%) after 1 month, 20/24 (83%) after 3 months, 22/24 (92%) after 1 year, and 23/24 (96%) after 2 years. Immediate complete closure of the shunt was achieved in all patients in whom the implant right atrial disk diameter to d value was > 1.1:1, confirming our suspicion of a higher closure rate with oversized devices, whereas after 24-hour follow-up, a small residual shunt was observed only in the 8 patients in whom the implant right atrial disk diameter to “d” value ratio was 1:1. There were no ICE-related complications, and no patients experienced symptoms during follow-up. Discussion The current study presents the first long-term follow-up of perforated ASD transcatheter closure using a single Amplatzer PFO or Cribriform occluder device in a patch-like fashion under ICE guidance. Currently, three different techniques for transcatheter closure of perforated ASDs have been reported. The first technique involves the simultaneous implantation of two Amplatzer Septal occluder devices. This usually requires that the distance between the two holes should be at least 7 mm, and it is recommended to deploy the smallest device first, with the larger device overlapping the smaller one.^4,5 The second technique imposes a balloon atrial septostomy maneuver in order to create a confluence between the holes before placing a single larger Amplatzer Septal occluder.6 Both techniques have their own drawbacks. On one hand, there are no experimental or clinical data on the endothelization of the Amplatzer prosthesis when two devices overlap each other, because there is a point of no contact with the endocardial surface of the atrial septum. On the other hand, the balloon atrial septostomy seems to be a hazardous maneuver, because the new larger hole is not regularly elliptical in shape, and the resulting estimated balloon sizing is unpredictable, leading to both undersizing or oversizing of the generated defect. Finally, it has been recently demonstrated that perforated ASDs may be effectively closed with a single Amplatzer septal occluder device if the distance from the main defect to the second communication is less than 7 mm.¹¹ The results of this study compare favorably to the experience reported by Szkutnik et al.¹¹on transcatheter device closure using a single Amplatzer septal occluder. Szkutnik’s report demonstrated the same progressively decreased shunting through the defect over the course of follow-up. Moreover, this paper adds new, qualitative and quantitative information, with several clinical implications. First, it has been shown that ICE allows clear visualization of the two guidewires and their eccentric or central position across the flap valve on the two orthogonal planes. Second, it has been demonstrated that ICE identifies a vertical fossa ovalis major axis, meaning that it is on the parasagittal plane in respect to the body. Third, a sufficiently close agreement has been found between measured GW-R distances and rp-derived values, suggesting that the guidewire approximately crosses through the focus of the elliptical fossa ovalis, as demonstrated by means of geometric assumptions derived from the properties of the ordinary conic sections. Finally, it has been indirectly established that an implanted right atrial disk diameter to “d” value ratio of >= 1.1:1 might better warrant an immediate complete closure of the perforated ASDs, whereas the closing mechanism of the residual shunt may be due to delayed neointimal formation along the edges of the non-oversized devices. In conclusion, perforated ASDs may be effectively closed with a single Amplatzer PFO or Cribriform occluder device. The ICE-guided “double guidewire” technique seems to be a rational way to employ the Amplatzer device as a patch-like prosthesis, minimizing both the costs of two implanted devices and the risks of balloon atrial septostomy techniques. Moreover, our suggested strategy may simplify these challenging procedures.

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