Efficacy of treatment of severe carotid bifurcation stenosis by using self-expanding stents without deliberate use of angioplasty balloons

Abstract

Background and purpose: One of the limitations of carotid artery angioplasty is the potential for embolic stroke. Our purpose was to assess whether the force of a self-expanding stent alone is usually sufficient to dilate severely stenotic atherosclerotic plaques without the deliberate use of an angioplasty balloon. If so, the procedural stroke risk might be reduced.

Methods: Over a 30-month period, 21 consecutive patients were prospectively identified with severe symptomatic carotid artery stenosis (>70% NASCET [North American Symptomatic Carotid Endarterectomy Trial]) and relative indications for endovascular treatment. All underwent treatment with the aim of deploying a self-expanding stent across the stenosis without the use of angioplasty balloons or distal protection devices.

Results: Stent deployment was successful in 20/21 patients. In one patient, the stent could not be deployed without balloon predilatation and a stroke occurred. In the other 20 patients, angiography before and immediately after stent deployment showed a reduction in the mean stenosis from 83% to 49%. A second periprocedural stroke occurred as a result of early stent thrombosis at 4 days in a patient who stopped Acetylsalicylic acid while undergoing bowel preparation for colon surgery. He made a good recovery. Average duration of follow-up imaging was 19 months (range, 1-44 months). During the follow-up period there were four deaths, all unrelated to the carotid disease, and no major strokes. At 5-11 months, the average residual stenosis was 21%, which remained stable in 16 of the 18 patients studied between 12 and 44 months (average, 24 months). At last follow-up, in these 16 the mean peak systolic velocity was 123 cm/s (range, 60-238 cm/s) and the mean internal-to-common carotid ratio was 1.8. The other two patients were long-term failures of the "stent-only" approach. In one patient, a heavily calcified plaque prevented stent expansion and the artery occluded at 18 months with a minor stroke. In the second patient, a recurrent stenosis developed at 16 months with one episode of transient ischemic attack.

Conclusion: Deployment of a self-expanding stent alone resulted in a favorable and more gradual reduction of severe symptomatic carotid stenosis. Improvements in stent profile and chronic outward force may widen the indications for simple stent placement without the use of balloons or adjunctive protection devices.

Fig 1.

A, Right CCA digital subtraction arteriogram (DSA), lateral view, showing a very severe atherosclerotic stenosis of the proximal ICA, >95% by NASCET criteria (arrow). B, Repeat DSA, lateral view, immediately poststenting alone, without balloon angioplasty, showing a reduction in the degree of stenosis to approximately 29%.

Fig 2.

A, Left CCA DSA, AP view, showing a severe stenosis of the proximal ICA, measuring approximately 76% (arrow). B, Repeat DSA, AP view, immediately poststenting without balloon angioplasty, showing reduction of the stenosis to approximately 50% (arrow). C, Follow-up DSA, AP view, 3 years poststenting alone, shows no residual ICA stenosis. D, E, and F, Conventional AP radiographs of the neck immediately poststenting (D), 1 month (E) and 8 months (F) poststenting, showing progressive opening of the stent waist (arrow), with maximum expansion occurring in the 1st month postprocedure.

Fig 3.

Follow-up radiologic results based on initial angiography and subsequently conventional radiographs of the stented artery. Degree of stenosis measured according to NASCET method.

Fig 4.

Follow-up sonography results based on peak systolic velocity measurements, Matched pairs of measurements in the same patients at different time intervals after stent placement.

Fig 5.

Follow-up sonography results based on ratio of ICA to common carotid velocity. Matched pairs of measurements in the same patients at different time intervals after stent placement.

Fig 6.

A, Right lateral CCA DSA, showing a severe stenosis of the proximal ICA, measuring approximately 80%. B, Repeat lateral DSA, poststenting alone, showing reduction of the stenosis to approximately 63%. C, D, and E, Conventional AP radiographs of the neck immediately poststenting (C), 5 months (D), and 8 months (E) poststenting. There has been no further expansion of the stent over 8 months. Note the prominent, focal plaque calcification (arrows).

Fig 7.

Table showing breakdown of results according to the degree of immediate or delayed expansion of the self-expanding stent. Percentage results are according to the NASCET criteria, based on the widest luminal diameter of the metallic stent beyond point of maximum stenosis.