Code Stroke Activation Following Cardiac Catheterization Procedures: Contrast-Induced Encephalopathy Versus Stroke

Contrast-induced encephalopathy (CIE) is a rare but clinically significant complication following intra-arterial iodinated contrast administration, often mimicking acute ischemic stroke (IS). Its true incidence following cardiac catheterization procedures remains poorly defined.

This study aimed to evaluate the incidence of CIE following cardiac catheterizationprocedures and to characterize its clinical presentation, diagnostic features and outcomes.

We conducted a single-center retrospective cohort study at an academic institution, evaluating all in-hospital code stroke activations from January 2016 to December 2022 (n = 855). Cases occurring after cardiac catheterization (n = 16) were reviewed in detail to identify those consistent with CIE based on clinical presentation, neuroimaging, and exclusion of alternative diagnoses. Diagnoses were adjudicated by a stroke neurologist.

Among 34,760 coronary procedures performed during the study period, two cases of probable CIE were identified, yielding an incidence of 0.006%. Both patients were elderly with chronic hypertension and underwent diagnostic angiography with < 100 mL of hypo-osmolar iodinated contrast. Neurological symptoms developed within minutes to hours post-procedure. In both cases, symptoms resolved completely within 24-48 h with conservative management.

CIE is a rare complication of cardiac catheterization procedures, but its stroke-mimicking presentation poses diagnostic and therapeutic challenges. We discuss diagnostic imaging strategies, risk factors such as hypertension and contrast volume, and propose clinical measures to enhance recognition and avoid mismanagement. Increased interdisciplinary awareness, careful risk factor mitigation, and integration into post-catheterization stroke protocols are critical to prevent misdiagnosis and inappropriate interventions. Despite the diagnostic uncertainty it may cause, CIE generally carries an excellent prognosis with complete symptom resolution in most cases. Further multicenter studies are needed to refine diagnostic criteria and guide management strategies.