KAROTIS-EVERSIONSZYLINDER: IDEALES MORPHOLOGISCHES SUBSTRAT ZUR EX-VIVO-QUANTIFIZIERUNG VON KAROTISSTENOSEN

Purpose. Multicenter trials (ECST, NASCET) were able to demonstrate that the angiographically obtained degree of stenosis of the extracranial internal carotid artery is the most reliable predictor for stroke despite several reports pointing out that carotid artery stenosis might angiographically be underestimated. Obtaining intact carotid eversion specimens (CES) following carotid eversion endarterectomy, both linear and plane assessment of the stenosis of the internal carotid artery (ICA) was provided ex vivo, thus verifying the preoperative angiography results. In comparison with the CES, CT angiography (CTA) has not yet been evaluated. Methods. Special casts of every ICA stenosis were prepared by means of methylmethacrylate (Palavit M) in 54 CES and were planimetrically surveyed (both diameter and plane) at the narrowest segment. The local (ECST criteria) and distal degree (NASCET criteria) of the ICA stenosis was evaluated and compared to the preoperative angiography (selective n = 27, non-selective n = 27 CT angiography n = 12) regarding reduction in diameter and plane each (formula: π x r²) CTA. Statistical analysis was performed by means of the non-parametric Wilcoxon matched-pairs test or the paired Student's test. Results. Non-selective angiography significantly underestimates both the local (mean 77.8%) and distal (mean 70%) degree of the ICA stenosis; reduction in diameter/plane locally at the site of CES: 82.8%/91.6% (P = 0.007, P < 0.001), distally: 75.9%/83.4% (P = 0.03/P < 0.001). Assessment of the local and distal degree of the ICA stenosis was more accurately made by selective angiography: 82.9%/75.6%, respectively; reduction in diameter/plane at the site of CES locally 83.3%/89.5% (n.s./P < 0.001), and distally 79%/82% (n.s./P < 0.05). Sensitivity of the non-selective angiography for the high-grade stenosis (≥ 70%) was 85.2% (locally) and 60% (distally), respectively, in contrast to the selective angiography: 100% and 91.3%, respectively. Local degree of the ICA stenosis was precisely determined by means of CTA (CES mean 83%, CTA mean 83%); the distal degree of stenosis was slightly overestimated (79% vs 81%, n.s.). Conclusions. (1) Planimetry of CES allows both the linear and plane degree of ICA stenosis to be evaluated; (2) ICA stenosis might easily be underestimated by angiography; reliable quantification of a high-grade ICA stenosis (≥ 70%) can only be achieved by selective angiography; (3) local degree of ICA stenosis is assessed exactly by means of CTA.