Role of Imaging in Interventions on Structural Heart Disease
Role of Imaging in Interventions on Structural Heart Disease
Several instrumental techniques are available for the accurate assessment of PFO. Their relative characteristics are summarized in Table 1.
TTE (second harmonic mode) is used to evaluate cardiac structure, interatrial septum motility and potential causes of cardiac embolism; it is recommended that TTE should be performed in all patients suspected of having a PFO.
TTE, done with a saline bubble test, can be useful in diagnosing a clinically relevant intracardiac shunt at rest and after Valsalva maneuver. The inter-atrial shunt is defined as the presence of contrast in the left atrium within the first 3 to 5 cardiac cycles after contrast has entered the right atrium. Shunt quantification is: mild or moderate <20 bubbles; severe >20 bubbles. When bubbles are detected in the left atrium after 3 to 5 cardiac cycles, an arteriopulmonary shunt is suspected.
The contrast-enhanced transcranial Doppler ultrasonography (TCD) does not help imaging the PFO, but is much sensitive in detecting a right-to-left shunt if more than 10 air micro-bubble spikes in the middle cerebral artery are evident.
Patent Foramen Ovale
Several instrumental techniques are available for the accurate assessment of PFO. Their relative characteristics are summarized in Table 1.
TTE (second harmonic mode) is used to evaluate cardiac structure, interatrial septum motility and potential causes of cardiac embolism; it is recommended that TTE should be performed in all patients suspected of having a PFO.
TTE, done with a saline bubble test, can be useful in diagnosing a clinically relevant intracardiac shunt at rest and after Valsalva maneuver. The inter-atrial shunt is defined as the presence of contrast in the left atrium within the first 3 to 5 cardiac cycles after contrast has entered the right atrium. Shunt quantification is: mild or moderate <20 bubbles; severe >20 bubbles. When bubbles are detected in the left atrium after 3 to 5 cardiac cycles, an arteriopulmonary shunt is suspected.
The contrast-enhanced transcranial Doppler ultrasonography (TCD) does not help imaging the PFO, but is much sensitive in detecting a right-to-left shunt if more than 10 air micro-bubble spikes in the middle cerebral artery are evident.
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