Abstract 1122‐000070: Multiple Watershed Strokes Following Catheter Ablation Procedure
Authors: Babici Denis , Bayas Angel , Hanafy Khalid 
Published: December 2021

Introduction
: Cerebral watershed strokes involve the junction of two non‐anastomosing arterial systems, which are hemodynamic zones at risk. Strokes occur in 3% to 9% of patients after cardiac procedures. The mechanism underlying post‐cardiac surgery watershed stroke involves a combination of hypoperfusion and embolization, but the role of hypoperfusion has not been well elucidated. Watershed strokes in the general population are usually secondary to global hypoperfusion, such as during cardiac arrest, but may also be attributable to stenosis of the carotid artery or other major vessel, leading to local hypoperfusion. Atrial fibrillation confers a threefold to fivefold increase in the risk of stroke, causing 15–20% of all thromboembolic events in the United States. Catheter ablation of atrial fibrillation is the treatment of choice, and currently one of the most commonly performed electrophysiology procedures in the United States. Successful catheter ablation in patients with atrial fibrillation is associated with a decrease in systolic blood pressure. One study showed that in patients with hemodynamically significant stenosis, the average decrease in mean blood pressure during TIA attack was 26.4. mm Hg. In addition, carotid artery stenosis is frequently associated with stenosis of the vertebral arteries, carotid siphon, and cerebral arteries. In these patients, cerebral blood flow is directly dependent on perfusion pressure, due to the loss of normal autoregulatory capacity in the cerebral circulation.

Methods
: Single Case Study

Results
: 84‐year‐old male patient with a past medical history of hypertension, gastrointestinal hemorrhage, coronary artery disease status post coronary artery bypass graft, prostate cancer, and atrial flutter on Apixaban status post recent catheter ablation performed five days prior to presentation at the hospital. Patient presented to the emergency room with complaints of spotty vision. The remainder of the neurologic exam was unremarkable. Patient’s vision changes started after the cardiac ablation procedure and progressively worsened. At the time of assessment, NIH score was 1 due to left eye hemianopsia. CT scan of the head without contrast was done and was negative for hemorrhage. CTA of the neck showed 60% stenosis of the left carotid artery. MRI of the brain was done and showed infarct zones between the right anterior cerebral artery and right middle cerebral artery, the right middle cerebral artery and right posterior cerebral artery, the left anterior cerebral artery and left middle cerebral artery, and in the area supplied by the right posterior cerebral artery. Interestingly, based on the radiologic features, all of these strokes happened at approximately the same time.

Conclusions
: This case demonstrates that even in asymptomatic patients with hemodynamically insignificant carotid stenosis, hypotensive episodes can elicit hemodynamically significant changes that may result in ischemic stroke. Current guidelines don’t include radiologic assessment of the carotid arteries before catheter ablation procedure in patients with known atherosclerotic disease. Based on our findings, in patients with known atherosclerotic disease, we recommend radiologic assessment of the carotid arteries prior to catheter ablation. Patient who undergo catheter ablation usually have an echocardiogram done prior to the procedure.