LETTER
Transient Ischemic Attack after Air Contrast Echocardiography in Patients with Septal Aneurysm
T. Narain Srivastava and
Eric K. Undesser
1 March 1995 | Volume 122 Issue 5 | Page 396
TO THE EDITOR:
Intravenous air is frequently used during echocardiography to show right-to-left heart shunting [1]. Small amounts are considered safe because of the lung's filtering action. Associated cerebral ischemic symptoms have not been reported either because of their infrequency or subtlety or because of a reluctance to report an iatrogenic complication. We have done 46 air contrast studies in patients in whom atrial septal aneurysm was diagnosed during routine echocardiography. Right-to-left shunts were found in seven patients, and transient ischemic attacks occurred in three patients.
Contrast echocardiography [2] was done using 10 mL of agitated air and normal saline. No patient had a history of transient ischemic attack. In two patients, transcranial Doppler studies were done during or after the procedure. Air emboli were identified in both patients for as long as 2 hours by their characteristic audio "chirps" and transcranial Doppler waveform [3].
All symptoms appeared when patients arose, and they resolved in minutes or hours. Neurologic deficits consisted of dizziness and paraparesis with numbness in patients with large shunts; diplopia, left hemiparesis, and right seventh-nerve weakness in patients with moderate shunts; and left upper extremity numbness and paresthesias in patients with small shunts.
Air embolism appeared to be responsible for the observed symptoms because no patient had a history of transient ischemic attack and because symptoms occurred soon after procedures done with documented intracranial air emboli. Clinicians should exercise care when injecting air bubbles, given the risk for neurologic deficits. Vigorous agitation of the air contrast to reduce bubble size does not completely eliminate this risk. Use of a more soluble gas, such as oxygen or carbon dioxide, may be prudent. Further, because of the risk for paradoxical air embolism in patients with unsuspected right-to-left heart shunts, great care should be exercised in the flushing and proper connection of intravenous lines in all patients.
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Author and Article Information
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Veterans Affairs Medical Center, Jackson, MS 39216.
1. Valdes-Cruz L, Pieroni D, Roland J, Varghese J. Echocardiographic detection of intracardiac right-to-left shunts following peripheral vein injections. Circulation. 1976; 54:558-62.
2. Henry WL, DeMaria A, Gramiak R, et al. Report of the American Society of Echocardiography Committee on nomenclature and standards in two-dimensional echocardiography. Circulation. 1980; 62:212-7.
3. Spencer MP. Detection of cerebral arterial emboli. In: Newell DW, Aaslid R, eds. Transcranial Doppler. New York: Raven Press; 1992:215-30.
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