(146) Severe Carotid Artery Stenosis Can Cause Cardiac Arrest!

Introduction: Carotid artery stenosis commonly causes transient ischemic attacks (TIAs) – short-lived symptoms with a distinct neurological territory. However, the impact of symptomatic carotid artery stenosis on hemodynamics has been variably described. We present a case of TIA associated with recurrent symptomatic bradycardia and cardiac arrest.

Description: A 62 year-old man with previously controlled hypertension presented after an episode of new-onset left facial numbness and left-sided weakness, and was admitted for presumed TIA. CT angiography revealed bilateral internal carotid artery (ICA) stenosis with 80% right proximal stenosis and 50-60% left stenosis. During his admission, he had recurrent episodes of symptoms when standing that lasted less than 10 minutes. These episodes were associated with hypertension with systolic blood pressures greater than 200 mm Hg and bradycardia to 40s with complete heart block. He had one episode of loss of consciousness for less than 10 secs with asystole and spontaneous recovery. Subsequent pacemaker placement was complicated by intraoperative asystole, and ACLS protocol was started with 1 round of chest compressions. A few days later, he had a transcarotid artery revascularization (TCAR) and stent placement of the right ICA. Since the TCAR, he has not experienced any additional episodes of bradycardia and the pacemaker has not been triggered.

Discussion: Carotid artery stenosis varies from asymptomatic presentation to severe recurrent TIA-like episodes due to cerebral hypoperfusion. Carotid artery stenosis also contributes to baroreceptor failure with subsequent sympathetic hyperactivation and labile hypertension. Our patient did not have bradycardia after TCAR. These observations suggest that his episodic hypertension precipitated reflex AV block with bradycardia. Paradoxically, while hypertensive crises due to baroreceptor failure typically manifest with tachycardia, we hypothesize the location of the proximal stenosis was sufficiently close to the carotid sinus to stimulate a carotid sinus response after onset of severe hypertension. This report suggests that paradoxical bradycardia with hypertension may be a warning sign of severe proximal internal carotid artery stenosis and warrants aggressive evaluation and monitoring.