Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy

Abstract

Background: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials.

Methods: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up.

Results: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface.

Conclusions: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials.

Keywords: atherosclerosis; carotid stenosis; endarterectomy; endovascular treatment; plaque length; restenosis.

Fig 1

Measurement of length of stenosis. Stenosis length 1 (red line): distance between the two definite shoulders of the lesion. Stenosis length 2 (blue line): distance between the proximal and distal points where the degree of stenosis decreases to 80% of its maximum. Stenosis length is expressed as a fraction of the diameter (D) of the undiseased CCA. Examples a–c show length 1 and length 2 in different situations. (a) two definite lesion shoulders are present – length 1 and length 2 are similar; (b) two definite lesion shoulders are present but lesion proximally extends to carotid bifurcation – length 1 > length 2; (c) no definite lesions shoulders – only measurement of length 2 is possible. CCA, common carotid artery; ICA, internal carotid artery; ECA, external carotid artery.

Fig 2

Study profile. *, 2 fatal strokes, 1 perforated duodenal ulcer. §, complications of preoperative cardiac pacing. EVT, endovascular treatment; CEA, carotid endarterectomy; DSA, Digital Subtraction Angiography; MRA, Magnetic Resonance Angiography; US, ultrasound; CTA, Computed Tomographic Angiography.

Fig 3

Peri-procedural stroke or death across quartiles of length of stenosis. Bars represent percentages of patients with the combined outcome event, vertical lines represent standard errors. See text for definition of length of stenosis. EVT, endovascular treatment; CEA, carotid endarterectomy.

Fig 4

Comparison of peri-procedural stroke or death, nonprocedural ipsilateral stroke, and restenosis ≥50% between treatment arms, according to anatomical factors. Unadjusted odds ratios and hazard ratios with 95% confidence intervals (95% CI) of outcome events in EVT compared with CEA. Median degree of stenosis was 81% according to the method used in the NASCET trial. Threshold length of stenosis was 0.65 times the diameter of the distal common carotid artery, using the definition of length 2 (see text for details). *, P = 0.003 for interaction between length of stenosis, treatment, and restenosis. EVT, endovascular treatment; CEA, endarterectomy.

Fig 5

Cumulative incidence of restenosis ≥50% in both treatment arms, according to length of stenosis at baseline. Threshold length of stenosis was 0.65 times the diameter of the distal common carotid artery, using the definition of length 2 (see text for details). The interaction between length of stenosis, treatment, and restenosis was significant (P = 0.003). EVT, endovascular treatment; CEA, endarterectomy; HR, hazard ratio (95% confidence interval).