2.1.1

TEE protocol

TEE was conducted using a GE Vivid7 (General Electric Corp., Nowrfolk, and VI, USA) with contrast injection and Valsalva maneuver under local anesthesia: R-L shunt was defined as permanent, small, medium, and large following Homma et al. , whereas atrial septal aneurysms (ASA) were classified according to Olivares et al. . PFO diameter was calculated measuring with electronic caliper the maximum opening of the PFO in the end-diastolic frames. Atrio-ventricular function was evaluated following the standard recommendations .

2.1.2

Transcranial Doppler (TDC) protocol

TCD was performed using intravenous bubble study by a neurologist experienced in this examination, according to current standard and using a TCD monitoring device (DWL MultidopX, ScanMed Medical, UK). Both MCAs were simultaneously monitored through the temporal window by the use of 2-MHz probes. The contrast was obtained by mixing 100 cm ³ of saline solution with 2–3 cm ³ of Emagel and loading a 10 cm ³ syringe with this mixture. The solution, agitated between two 10-mL syringes, connected by a 3-way stopcock, was immediately injected with a 20-gauge/32-mm catheter placed in the antecubital vein to obtain a bolus of air microbubbles. This procedure was performed 3 times during normal breathing and the same number of times during a Valsalva maneuver. The bolus of microbubbles was injected in 1 to 2 s when this 7-s period ended. We quantified the importance of R-L shunting by counting the number of signals in 1 MCA within 7 s of the injection, as previously reported: Mild (<10 bubbles within three cardiac cycles), moderate (> 10 bubbles within three cardiac cycles) with shower effect (many bubbles but still countable), severe (> 10 bubbles within three cardiac cycles) with curtain effect (many bubbles but not countable). A distinct pattern of shunt occurs when bubbles are identifiable before the Valsalva maneuver (basal or permanent shunt).

2.1.3

ICE study protocol

Patients who met the criteria for PFO closure were evaluated with an intracardiac echocardiography study using the mechanical 9F 9MHz UltraICE catheter (EP Technologies, Boston Scientific Corporation, San Jose, CA, USA) or the electronic 90° phased-array 8F intracardiac probe (ACUNAV, Biosense WebsterInc, Diamond Bar, CA, USA). The intracardiac echocardiography study was conducted as previously described , by performing a manual pull-back from the superior to the inferior vena cava through 5 sectional planes; measurement of diameters of the oval fossa, the entire atrial septum length and rims were obtained with electronic caliper edge-to-edge on the aortic valve plane and the 4-chamber plane. PFO tunnel length was also measured. Intracardiac echocardiographic monitoring of the implantation procedure was conducted on the 4-chamber plane. Normal diameter of fossa ovalis was defined as fossa ovalis < 15 mm in the four-chamber view.

Atrial septal aneurysms (ASA) were classified according to Olivares et al. : ASA were classified in 1 to 5 depending on the excursion of the aneurysm (5 being the most severe aneurysm), and as R or L depending on the prevalence toward the right atrium or the left atrium of the excursion. RL identified ASA with a bidirectional excursion in which right atrium excursion was preponderant whereas LR means bidirectional excursion but preponderant toward the left atrium.

Hypertrophic rims were defined as having a thickness ≥ 8 mm, whereas lipomatosis was defined as thickness of ≥15 mm, on ICE study. Long tunnel-type PFO was defined as length ≥ 10 mm by intracardiac echocardiogram.

2.1.4

Closure protocol

Combined antibiotic therapy [(gentamicin 80 mg plus ampicillin 1 g (or vancomicin 1 g if allergy has been recorded on anamnesis)] was administered intravenously 1 h before the procedure. The right femoral vein was catheterized through an 8 French sheath which was used for preoperative right cardiac catheterization, and replaced with a 9 or 12 French long sheath for device implantation, whereas the left femoral vein was catheterized through an 8 French sheath which was replaced with a pre-curved 9French long sheath for the intracardiac echocardiography study.

Device selection was accomplished on the basis of intracardiac echocardiography findings and measurements depending on the availability of different devices throughout the years. In the early period only the Amplatzer PFO Occluder (AGA Medical Corporation, Golden Valley, MN), whereas in the early 2000s the operator could to select the Amplatzer ASD Cribriform Occluder (AGA Medical Corporation, Golden Valley, MN) in case of bidirectional moderate aneurysm (3 RL or 3LR), in all the case of large aneurysm (4 and 5 RL or 4 and 5 LR) and in all the cases of multi-perforated atrial septal aneurysm being careful to cross the most central hole in the oval fossa with the guide-wire during intracardiac echocardiography guidance. After 2005 the Premere™ PFO Closure System (St. Jude Medical Inc. GLMT) was available and was selected when PFO tunnel length was more or equal to 10 mm, and in all case of hypertrophy of the Interatrial septum rims (thickness more than 10 mm). Indications for BiostarOccluder (NMT) during the period 2010–2012 were unidirectional and moderate (3RL or 3LR atrial septal aneurysm) aneurysm and clear allergy to nickel.

However, in all cases, independently from the device selected, care was taken to choose a device with an entire left disk diameter which possibly not exceeding the ratio device size/entire atrial septum length of 0.8 on intracardiac echocardiography.

2.1.5

Medications

Aspirin 100 mg for 6 months has been prescribed to all patients with no coagulation abnormalities who received a Premere or an Amplatzer devices. Aspirin 100 mg and Clopidogrel 75 mg for 6 months have been prescribed to patients who received the Biostar device. Warfarin for 6 months was prescribed to patients with coagulation abnormalities such as abnormal factor V of Leiden and anticardiolipin/antiphospholipid antibodies.

2.1.6

Definitions

Procedural success has been defined as implanted device with good position on ICE monitoring. Electrical complications were divided in acute (within 30 days) and long-term complications including temporary and permanent AF, temporary and permanent atrial flutter, temporary and permanent AVB, and supraventricular arrhythmias.

2.1.7

Follow-up

Cardiologic examination was scheduled at 1, 6, 12 months and yearly. TEE was scheduled at three months and repeated at 9-months post-closure if there was more than a trivial shunt, to assess for potential erosions or thrombosis and residual shunts. TDC ultrasound and magnetic resonance imaging of the brain were scheduled one month after the procedure. TTE was scheduled at 12 months after the transcatheter closure and yearly to assess mid-term residual shunt, and the effect of the device on atrial and heart valve function. Any residual shunt was graded as trivial, small, moderate, or severe as previously described . Holter 24-h monitoring was scheduled at 1 month after the procedure and at any time when felt necessary on the basis of clinical suspicion (anamnesis positive for palpitation) or on the basis of electrocardiogram (multiple supraventricular beats or more organized arrhythmias) recorded at any schedule cardiologic examination. Clinical examination was then scheduled yearly, whereas TTE was scheduled every two years, if no events were reported. No patient was lost during the follow-up period (see Fig. 1 .)

2.1.8

Statistical methods

Data have been expressed as mean ± SD and percentages. Stepwise logistic regression analysis was used to determine independent determinants of electrical complications (any of atrial fibrillation, supraventricular arrhythmias, atrio-ventricular block of any grade) after closure. The analyzed variables were age, sex, grade of atrial septal aneurysm (ASA), permanent R-L shunt on TCD, shunt grade on TEE, rim thickness ≥ 8 mm, tunnel length ≥ 10 mm, device disk >30 mm, and a mean ratio between device size and entire atrial septum length ≥ 0.8, type of device (Amplatzer, Biostar and Premere). Cox regression has been performer during the follow-up. Statistical analysis was performed using a statistical software package (SAS for Windows, version 8.2; SAS Institute; Cary, NC). A probability value of <0.05 was considered to be statistically significant.