Intracardiac Echocardiography and Transcranial Doppler Ultrasound to Guide Closure of Patent Foramen Ovale

Patent foramen ovale (PFO) is increasingly recognized as a mediator of Patent foramen ovale (PFO) is increasingly recognized as a mediator of paradoxical embolism,1,2 refractory hypoxemia3,4 and platypnea-orthodeoxia syndrome.5–7 Many specialists are involved in PFO patient care, such as vascular surgeons, neurologists, respiratory physicians, and cardiologists; an interdisciplinary working group assumes special importance in the management of this disease. For a long time, transthoracic (TTE) and transesophageal (TEE) echocardiography were considered the main imaging tools for diagnosing PFO, and color Doppler modality, injection of micro-bubble contrast agents, Valsalva or coughing maneuver have increased their sensitivity and specificity8,9 over time. In recent years, innovative and multidisciplinary approaches to diagnosis have been developed including contrast transcranial Doppler (TCD) examination of the middle cerebral artery,10 dye dilution and ear oximetry bedside tests,11,12 transmitral TTE Doppler contrast study,13 harmonic imaging (HI) echocardiographic technique,14,15 bed tilt contrast TTE16 and intracardiac echocardiographic (ICE) technology.17 To the best of our knowledge, this case is the first to show PFO closure using both ICE to guide device deployment as an adjunct to biplane fluoroscopy, and contrast TCD score with provocative maneuver to quantify in real time the intraprocedural degree of right-to-left shunt.18 Case Report. A 63-year-old man with severe chronic obstructive pulmonary disease and PFO associated with a concomitant atrial septal aneurysm underwent cardiac catheterization, ICE evaluation and contrast TCD study under local anesthesia. A screening oxygen saturation measurement for right-to-left shunt was carried out. Assessment of the fossa ovalis anatomy and PFO morphology was performed using ICE tomographic imaging at orthogonal axial aortic valve and sagittal 4-chamber planes. Concurrently, hemodynamic evaluation of right-to-left shunt was examined by means of contrast TCD using a standardized protocol.19,20 The PFO was occluded with a 35 mm Amplatzer PFO Occluder (AGA Medical Corporation, Golden Valley, Minnesota), which was introduced via the right femoral vein using the 9 French (Fr) delivery system. The device was deployed under ICE guidance using a 9 Fr, 9 MHz Ultra ICE catheter (EP Technologies, Boston Scientific/Scimed, Inc., Maple Grove, Minnesota), inserted through the left femoral vein. Contrast TCD examination with the Valsalva maneuver was performed before, during and after of the procedure to estimate in real time the magnitude of the shunt flow. A 2 MHz, pulsed-Doppler transducer (Eden Medical Electronics, Inc., Kent, Washington), which evaluated flow in the middle cerebral artery though the temporal bone window, was used. The fluoroscopy and total procedure times were 10 minutes and 30 minutes, respectively. ICE provided unique images of the morphological and functional characteristics of the fossa ovalis structures (Figure 1) and played a pivotal role in the deployment of the 2 disks of the device on the appropriate side of the atrial septum (Figure 2). Contrast TCD with the Valsalva maneuver revealed important shunts before and after device deployment. After releasing the device, no residual atrial shunt was detected either during normal breathing or during a Valsalva maneuver (Figure 3). The post interventional course was uneventful, and the patient was discharged 1 day post-procedure, commencing aspirin 100 mg once daily and prophylactic antibiotic therapy for 6 months. Discussion. The prevalence of PFO in patients with severe chronic obstructive pulmonary disease is high and a PFO was detected four times more frequently in 48 consecutively studied patients than in control subjects by Sanoudy et al.21 The only proven chronic obstructive pulmonary disease-related cause of stroke is a transient rise of pressure inside the right-sided cardiac chambers, causing right-to-left shunting of venous blood across an incompletely sealed PFO. Small series of patients with pulmonary embolism,22 right ventricular infarction23 and patients undergoing positive pressure ventilation24 have also confirmed this hypothesis. In such patients, preliminary data suggest that surgical25,26 or percutaneous27,28 closure of the PFO can prevent recurrent cerebral events. Current devices permit transcatheter closure using peri-interventional TEE to establish the presence of PFO, to guide device deployment and to establish procedural success. However, TEE is not suitable for a routine examination in all patients, especially in those with severe chronic obstructive pulmonary disease, swallowing dysfunction or poor cooperation. Moreover, patient discomfort, the need for general anesthesia for sedation and risk of early obstruction are other disadvantages of contrast TEE over TCD. Thus, ICE and contrast TCD seem to be alternative methods for an exhaustive evaluation of PFO during transcatheter closure, especially in patients suffering from stroke or chronic pulmonary disease. First of all, ICE is useful for optimal device deployment. The left atrial disk can be seen fully open in the mid-left atrium (Figure 2A) and firmly seated against the atrial septum (Figure 2B). ICE also allows visualization of the right atrial disk providing important information on effective application of the PFO occluder. At this stage of the deployment process, the tension applied by delivery cable twists its shape and form (Figure 2C). After complete release, the device adapts itself to take a characteristic appearance resembling a “flying-saucer” (Figure 2D). This appearance is created by the two flattened retention disks producing a multiray reflection pattern on either side of the atrial septum and the conjoint waist of the device that threads across the oblique-angled pathway of the PFO. Moreover, contrast TCD is an ideal method to noninvasively quantify right-to-left shunt,18 actually allowing evaluation of the cerebral consequences of PFO by real time detection of bubble passage across the brain arteries. Its sensitivity and specificity are higher than contrast TEE.29 This discrepancy is a well-known phenomenon, mainly due to non-effective Valsalva maneuvers caused by the presence of the TEE probe in the esophagus and by deep sedation. In our opinion, the combination of ICE imaging and contrast TCD enables the physician to take advantage of appropriate therapeutic guidelines for successful deployment of the Amplatzer PFO Occluder and probably of other PFO closure devices. We believe that an interdisciplinary collaboration among the cardiologist, the respiratory physician and the neurologist could be important for recognition, correct evaluation and percutaneous therapy of patients with PFO and chronic obstructive pulmonary disease.

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