Case presentation

A 46-year-old man with a history of recent stroke underwent a head MRI scan and was found to have evidence for both an acute posterior parietal infarct as well as an older frontal infarct. He originally presented with right facial droop and slurred speech; this gradually improved over several months. He underwent several studies to explore the cause of his stroke; a carotid ultrasound with Doppler and hematologic evaluation for a hypercoagulable state found no abnormalities. A transesophageal echocardiogram was performed and demonstrated a long, tunnel-like patent foramen ovale (PFO). Right-to-left shunting on a contrast echo “bubble study” was seen at rest and was apparent even without a Valsalva maneuver. His medications included atorvastatin and aspirin. There was no history of drug or nickel allergy. The medical history was otherwise significant for snoring and he had a family history of premature coronary artery disease. On physical examination, the patient was normotensive and the oxygen saturation was 98% on room air. Jugular venous pressure was normal, the lungs were clear, and there were no pathological murmurs. There was no cyanosis or edema and the pulses were symmetric. The ECG exhibited sinus rhythm and was otherwise normal.

Cardiac catheterization

The patient was referred for percutaneous closure of the patent foramen ovale. The operator attained venous access in the right femoral vein using two vascular sheaths, 11 Fr and 9 Fr respectively. No contrast was used during this procedure, and the PFO closure was done using fluoroscopic and intracardiac echocardiographic guidance. An ACUSON AcuNav™ intracardiac ultrasound catheter was advanced through the 11 Fr sheath to the right atrium. The ICE catheter was rotated clockwise to attain views of the tricuspid valve and, subsequently, of the aortic valve. The catheter was retroflexed to view the septum (Video 47-1). After the intraatrial septum was well visualized and the absence of a thrombus attached to the PFO was confirmed, the patient was given 75 U/kg of unfractionated heparin. Subsequently, a 6 French multipurpose A2 catheter was passed to the right atrium through the 9 French sheath. The catheter was rotated posteriorly, easily crossing the patent foramen ovale into the left atrium with minimal manipulation. A 0.035 inch J-tip Amplatzer exchange length guidewire was passed into the left atrium and the multipurpose catheter removed. Stable wire position in a left pulmonary vein was confirmed by respiratory, but not cardiac, motion of the wire. A 9 French, 45 degree curved Amplatzer delivery sheath preloaded with a 25 mm Amplatzer Cribiform Septal Occluder was advanced across the interatrial septum and the left atrial disk was delivered under fluoroscopic and intracardiac echocardiographic guidance (Figure 47-1 and Video 47-2). The delivery catheter was pulled back until the left atrial disk was snugly apposed to the septum, and the right atrial disk was delivered out of the sheath but remained attached to the delivery cable while positioning was confirmed both by fluoroscopy and by intracardiac echocardiography (Figure 47-2 and Video 47-3). Once a stable position was confirmed and each disk was observed by intracardiac echo in appropriate position with the interatrial septum appearing between the left atrial and right atrial disks, the Septal Occluder was released by rotating the delivery cable in a counterclockwise direction until the delivery cable was disconnected from the Occluder. The position was again confirmed by both fluoroscopy and by intracardiac echocardiography, including injection of agitated saline into the femoral vascular sheath to confirm absence of bubble contrast moving from right to left (Video 47-4).

FIGURE 47-1 This image is a still frame from an intracardiac echocardiogram recorded from the right atrium. The left atrial disk has been deployed within the left atrium but remains attached to the device delivery cable. The interatrial septum can be seen in the appropriate position behind the left atrial disk.

FIGURE 47-2 This image is a still frame from an intracardiac echocardiogram recorded from the right atrium. Both disks have been appropriately deployed. The left atrial disk can be seen on the left atrial side of the interatrial septum while the right atrial disk lies on the right atrial side of the septum. Note that gentle traction has been placed on the attachment cable to allow visualization of both disks with the interatrial septum lying between the two disks.

Postprocedural course

Following the procedure, the patient was admitted to the hospital for observation. He remained symptom-free during his stay. Device positioning was documented by chest radiography and by transthoracic echocardiography later in the day. The patient was treated with aspirin (325 mg daily) and clopidogrel (75 mg daily) for 1 month and provided instructions regarding antibiotic prophylaxis for endocarditis. At 1 month follow-up, the patient underwent repeat transthoracic echocardiography which confirmed a stable Septal Occluder position and absence of shunting. The clopidogrel was discontinued but aspirin prescribed indefinitely due to the history of prior stroke.

Discussion

In the United States, stroke is the third leading cause of mortality. Because nearly 23% of strokes are recurrent (occur in patients with prior strokes), secondary prevention is an important component of caring for these patients. A patent foramen ovale (PFO) has been reported in approximately 27% of patients evaluated by autopsy with otherwise structurally normal hearts. When evaluated by contrast echocardiography, nearly 15% of patients over age 39 without a history of stroke are found to have a PFO. Typically, the echocardiographic diagnosis of PFO is made when contrast microbubbles cross the interatrial septum from right to left within 3 to 4 cardiac cycles of right atrial opacification. Although a patent foramen ovale can provide a mechanism by which paradoxical emboli may pass from the right atrium into the left-sided circulation, there are still inadequate data to document the frequency by which this phenomenon results in stroke (or recurrent stroke). Similarly, it has not yet been possible to document with appropriate clinical trials that PFO closure can prevent such strokes. In addition, the optimal patient cohort to potentially treat with PFO closure has not been adequately defined by such randomized clinical trials.

At present, there are no Class I indications for the treatment of stroke and PFO (August/2009). Both the American Heart Association/American Stroke Association (AHA/ASA) and the American College of Chest Physicians (ACCP) guidelines recommend antiplatelet therapy for patients with ischemic stroke or transient ischemic attack and PFO (AHA/ASA Class IIa, ACCP Grade 1A), unless there are other, independent indications for warfarin (atrial fibrillation, hypercoagulable state; AHA/ASA Class IIa, ACCP Grade 1C). With respect to the prevention of stroke, these guidelines argue that there are no adequate randomized clinical data to recommend PFO closure in patients with a first stroke and a PFO. There is a Class IIb indication for PFO closure in patients with recurrent stroke despite optimal medical therapy.

It is important to note that the Food and Drug Administration (FDA) has not specifically approved any device for PFO closure following stroke, and that it strongly endorses the need for randomized clinical trials to address this important issue. Ideally, all patients treated for PFO and stroke would be enrolled in these randomized clinical trials.