Prediction of restenosis after carotid artery stent implantation

Follow-up results of carotid angioplasty with stenting as assessed by duplex ultrasound surveillance

BACKGROUND

Carotid artery stenting (CAS) has become an alternative modality to carotid endarterectomy (CEA) for the treatment of carotid occlusive disease. We report a retrospective review of our institution's experience with CAS versus CEA.

METHODS

Postprocedure surveillance duplex, recurrent symptoms, postprocedure strokes, progression of lesions, and rates of re-operation were analyzed in 46 patients who underwent CAS and 48 patients who underwent CEA. The mean length of follow-up evaluation was 13 months. All CAS procedures included neuroprotection devices.

RESULTS

Statistically significant differences in progression to critical restenosis (2% vs 2%, P = 1.0), rate of subsequent symptoms or stroke (2% vs 10%, P = .1), or rate of re-interventions were not observed between CAS and CEA groups (2% vs 4%, P = .98). Total mortality (0% vs 2%, P = .33), and the occurrence of major adverse events (2% vs 10%, P = .18) also were not significantly different in the CAS compared with the CEA patients. The average rate of increase in internal carotid velocity at 6 to 12 months (-1% vs 1.1%, P = NS) and 12 to 24 months (-5% vs -6.5%, P = NS) also were equivalent.

CONCLUSIONS

Our observed results indicate that CAS may be performed with comparable clinical outcomes and durability of repair comparable with CEA.

Complications and Follow-up after Unprotected Carotid Artery Stenting

PURPOSE

This prospective study was undertaken to determine the success rate, complications, and outcome of carotid artery stenting (CAS) without the use of cerebral protection devices.

METHODS

During 12 months, 94 high-grade stenoses of the carotid artery in 91 consecutive patients were treated. Sixty-six (70%) of the stenoses were symptomatic and 28 (30%) were asymptomatic.

RESULTS

In all 94 carotid stenoses CAS was successfully performed. During the procedure and within the 30 days afterwards, there were 2 deaths and 3 major strokes in the 66 symptomatic patients, resulting in a combined death and stroke rate of 5 of 66 (7%). Only one of these complications, a major stroke, occurred during the procedure. In the 6-month follow-up, one additional major stroke occurred in a originally symptomatic patient resulting in a combined death and stroke rate of 6 of 66 (10%) for symptomatic patients at 6 months. No major complications occurred in asymptomatic patients during the procedure or in the 6-month follow-up period. At 6 months angiographic follow-up the restenosis rate with a degree of >50% was 3 of 49 (6%) and the rate with a degree of >or=70% was 1 of 49 (2%).

CONCLUSIONS

Cerebral embolization during CAS is not the only cause of the stroke and death rate associated with the procedure. The use of cerebral protection devices during the procedure may therefore not prevent all major complications following CAS.

Prevention of carotid artery restenosis after sirolimus-coated stent implantation in pigs

BACKGROUND AND PURPOSE

To test the feasibility of self-expanding drug-coated nitinol stents for prevention of restenosis in an animal model. Stent implantation in the carotid artery (CA) has been shown to be feasible for treatment of CA stenosis. Even though the restenosis rate in CA is reported to be lower than in the coronary and peripheral arteries, problems may arise with increasing numbers of treated patients and lengthier follow-up.

METHODS

After predilatation with 8-mm balloons, 8 Goettinger minipigs were randomly selected to receive a sirolimus-eluting self-expanding nitinol stent (7 mm/80 mm) as well as the same stent without sirolimus/polymer coating in the right or left CA. Aspirin was given starting 3 days before the intervention and administered for an additional 4 weeks. Clopidogrel was administered for 10 days.

RESULTS

After 6 weeks, 2 subacute occlusions were observed in both groups. In the remaining vessels, the neointima was significantly reduced by sirolimus/polymer-coated stents (5.9+/-2.5 versus 0.7+/-1.0 mm2).

CONCLUSIONS

Sirolimus self-expanding nitinol stents may be an effective tool in reducing neointimal formation in CA.

Compliance matching stent placement in the carotid artery of the swine promotes optimal blood flow and attenuates restenosis

OBJECTIVES

We assessed the value of a gradient-compliant stent in an animal model.

METHODS

Bilateral carotid arteries were stented with nitinol stents having variable-oversizing, variable-stiffness, and with (CMS, 10 animals) and without (SMART, four animals) compliance-matching endings. Angiography, hemodynamic, scanning-electron-microscopic and histological analyses were performed at 3-month. The protocol was completed in 14 among 19 swines.

RESULTS

Transient (1-month) exaggerated recoil, attributable to stress-induced phasic inhibition of vasorelaxation, developed at CMS endings. At mid-term, all stents were endothelialized; CMS-stents, but not SMART-stents, were incorporated into walls (one-strut-thickness). Restenosis developed outside SMART-stents (cell migration+wall-compensatory enlargement) whereas CMS-stents elicited no or focalized cell-accumulations at endings that bulged vascular walls radially outward. SMART-stents were blood-flow neutral, whereas CMS-stents favored (higher-stiffness, higher-oversizing) or opposed (lower-stiffness, less-oversizing) carotid blood flow.

CONCLUSIONS

Direct carotid stenting with stents having compliance-matched endings and specific requirements of stiffness and oversizing can optimize blood flow to the brain and restrict local restenosis.