Transcatheter Closure of PFO and ASD: Multimodality Imaging for Patient Selection and Perioperative Guidance

Abstract

Transcatheter closure of patent foramen ovale (PFO) and secundum type atrial septal defect (ASD) are common transcatheter procedures. Although they share many technical details, these procedures are targeting two different clinical indications. PFO closure is usually considered to prevent recurrent embolic stroke/systemic arterial embolization, ASD closure is indicated in patients with large left-to-right shunt, right ventricular volume overload, and normal pulmonary vascular resistance. Multimodality imaging plays a key role for patient selection, periprocedural monitoring, and follow-up surveillance. In addition to routine cardiovascular examinations, advanced neuroimaging studies, transcranial-Doppler, and interventional transesophageal echocardiography/intracardiac echocardiography are now increasingly used to deliver safely and effectively such procedures. Long-standing collaboration between interventional cardiologist, neuroradiologist, and cardiac imager is essential and it requires a standardized approach to image acquisition and interpretation. Periprocedural monitoring should be performed by experienced operators with deep understanding of technical details of transcatheter intervention. This review summarizes the specific role of different imaging modalities for PFO and ASD transcatheter closure, describing important pre-procedural and intra-procedural details and providing examples of procedural pitfall and complications.

Keywords: atrial septal defect; multimodality imaging; patent foramen ovale; transcatheter closure.

Figure 1

Anatomy of atrial septum. Left panel shows right atrial view of atrial septum and anatomic relationship with superior vena cava, inferior vena cava, coronary sinus. The bulging of aorta toward the atrial septum (torus aorticus) is shown. The central insert is a TEE three-dimensional view showing the relationship between aortic root and fossa ovalis. The right panel represents a cross-anatomical section set at the level shown in the left panel. The extracardiac space between the aortic root (anteriorly) and atrial chambers (posteriorly) is the sinus transversus of pericardium. A TEE view of such space is presented in the right-top insert (*).

Figure 2

Anatomy of PFO. Detailed anatomy of PFO tunnel is presented. Three different cross-section planes are shown located at three different levels of septum primum. Due to the particular anatomy of septal attachment, central plane should be used for procedural measurement of PFO amplitude and length for proper device selection. Selected three-dimensional TEE left atrial view of PFO and appropriate cut for PFO amplitude measurement are presented. AO = AOrta; CS = Coronary Sinus; FO = Fossa Ovalis; IVC = Inferior Vena Cava; PFO = Patent Foramen Ovale; PV = Pulmonary Valve; SVC = Superior Vena Cava; TEE = Trans-Esophageal Echocardiography; TV = tricuspid valve.

Figure 3

Atrial septal defect and surrounding borders. Right atrial view of atrial septum is shown along with relationship between atrial septal defect and surrounding borders. Appropriate and border-specific TEE views are presented. Anatomical view is provided for comparison (left insert). TEE = Trans-Esophageal Echocardiography.

Figure 4

Neuroimaging features of embolic lesion. Diffusion-weighted MRI showing different lesion (arrowheads) patterns. (A) bilateral lesions in the right and left middle cerebral artery territory. (B) small subcortical lesion. (C) large corticosubcortical lesion in the right posterior cerebral artery territory. (D) multiple small lesions in the left middle cerebral artery territory. A cartoon showing cerebral vascular territories at the level of the body of the lateral ventricles (left image), at the level of the basal ganglia and internal capsule (center image) and at the level of the mesencephalon (right image) is provided.

Figure 5

Transcranial Doppler Study. Top row (left to right) shows basal TCD tracing, routine transcranial acoustic window and Valsava maneuver effect on TCD tracing. Bottom row shows suggest site for peripheral vein cannulation, mechanism of Valsalva-mediated effect on PFO-associated paradoxical embolization. The central tracing depicts a moderate shunt. Suggested threshold for TCD shunt grading with pertinent samples tracings are also presented. HITS: High Intensity Transient Signals; TCD = Trans-Cranial Doppler.

Figure 6

Challenging anatomies for PFO closure. Common anatomical features increasing procedural complexity and complication during PFO closure. PFO = Patent Foramen Ovale.

Figure 7

Challenging anatomies for ASD closure. Common anatomical features increasing procedural complexity and complication rate during ASD closure. ASD = secundum type Atrial Septal Defect; AVV = Atrio-Ventricular Valve; CS = Coronary Sinus.

Figure 8

Complication after ASD closure. Examples of complication or sub-optimal procedural result after ASD closure. Please note in (F), the presence of shunt between the device and torus aorticus is to be compared with normal “intra-device” flow seen in (G). Device embolization to the left ventricular cavity is shown in (I,J). ASD = secundum type Atrial Septal Defect; LA = Left Atrium; RPV = Right Pulmonary Valve; SVC = Superior Vena Cava.

Figure 8

Complication after ASD closure. Examples of complication or sub-optimal procedural result after ASD closure. Please note in (F), the presence of shunt between the device and torus aorticus is to be compared with normal “intra-device” flow seen in (G). Device embolization to the left ventricular cavity is shown in (I,J). ASD = secundum type Atrial Septal Defect; LA = Left Atrium; RPV = Right Pulmonary Valve; SVC = Superior Vena Cava.