Poststenotic Distal Caliber Reduction Predicts Very High-Grade Proximal Internal Carotid Artery Stenosis

Area of Science:

• Vascular Ultrasound
• Cerebrovascular Disease Assessment
• Medical Imaging Analysis

Background:

• Traditional angiography measures lumen reduction against the distal lumen (NASCET criterion).
• This method is unreliable in severe stenosis due to distal lumen collapse.
• The study investigated the utility of poststenotic caliber as an additional sonographic criterion.

Purpose of the Study:

• To evaluate the reduced poststenotic caliber as an additional sonographic criterion for estimating stenosis degree.
• To determine if distal lumen size can aid in differentiating severe internal carotid artery (ICA) stenosis.

Main Methods:

• Measured distal internal carotid artery (ICA) lumen caliber in patients with low-grade (<50%) and high-grade (≥50%) stenosis.
• Classified stenosis severity based on international recommendations and used poststenotic velocity criteria.
• Assessed interrater reliability for ultrasonic lumen measurements.

Main Results:

• Patients with 50-70% stenosis had a distal lumen of 4.3 ± 0.6 mm.
• Patients with ≥80% stenosis had a significantly smaller distal lumen of 2.6 ± 0.5 mm (p<0.0001).
• A distal lumen ≤ 3.2 mm accurately predicted very high-grade stenosis (sensitivity 0.92, specificity 0.96, AUC 0.986).

Conclusions:

• The distal poststenotic lumen serves as a valuable additional ultrasonic criterion for differentiating very high-grade ICA stenosis.
• This measurement can prevent misinterpretation of stenosis severity caused by variable intrastenotic velocities.
• Utilizing distal lumen size enhances diagnostic accuracy in complex ICA stenosis cases.