An Unusual Case of Embolic Stroke After Permanent Pacing
A 54-year-old Caucasian male transatlantic airline pilot with no cardiovascular risk factors presented to a neurology clinic after a transient episode of dysphasia. He reported no additional neurological symptoms. Eleven years previously, he had developed asymptomatic sinus node disease and had undergone implantation of a dual-chamber permanent pacemaker to retain his commercial pilot’s license. He was in sinus rhythm, was normotensive (120/70 mm Hg), and had no cardiac murmurs or carotid bruits. Neurological examination was normal.
A computerized tomography scan of his head showed a focal left cerebral infarct. Carotid ultrasonography, holter monitoring, and a thrombophilia screen were normal. A diagnosis of a left-hemisphere transient ischemic event was made. The patient was referred for a transoesophageal echo to exclude an intracardiac source of embolus. Structurally, the heart was normal, but on venous bubble contrast injection from the left arm, there was dense simultaneous opacification of both the left and right sides of the heart, without Valsalva maneuvers (Figure 1). Transthoracic images were subsequently repeated with bubble contrast from the right arm; on this occasion, there was no opacification of the left side of the heart, even with Valsalva maneuvers, effectively excluding a significant patent foramen ovale or intrapulmonary arteriovenous malformation (Movie I).
The patient underwent a venogram from the left basilic vein (Figure 2). This demonstrated a proximal occlusion of the left subclavian vein (in which the 2 pacing leads ran), 2 small collaterals crossing the mediastinum into the superior vena cava (which remained fully patent), and 1 large serpiginous collateral from the subclavian vein at the level of the occlusion draining directly into the left upper pulmonary vein.
The patient was anticoagulated. In view of likely paradoxical embolization through the venovenous right-to-left shunt, the patient was readmitted for closure of the collateral vessel. A 6-mm Amplatzer vascular plug (AGA Corporation, Plymouth, Minn) was deployed via a guide catheter from the left basilic vein, with complete closure of the collateral channel. Repeat contrast echocardiography the next day showed no residual shunt. The patient remains well with no further symptoms, but he has not been able to return to his former employment.
Occlusion of the access vein is a recognized complication of permanent pacing, with an incidence of 15% to 30%,1 unrelated to lead size or number.2 This occlusion rarely causes symptoms because venous collaterals quickly develop. Systemic-to-pulmonary venovenous collaterals have been reported in superior venacaval obstruction3 but not with subclavian vein occlusion alone. It represents a rare but important potential complication from transvenous pacemaker lead implantation.
The online-only Data Supplement, consisting of Movies I and II, is available with this article at http://circ.ahajournals.org/cgi/content/full/115/14/e386/DC1.