Predictors of carotid artery in-stent restenosis

Estimated Glomerular Filtration Rate as a Predictor of Restenosis After Carotid Stenting Using First-Generation Stents

This study evaluated the impact of the baseline estimated glomerular filtration rate (eGFR) on clinical and angiographic outcomes and long-term in-stent restenosis (ISR) rates in patients undergoing elective carotid artery stenting (CAS) procedures. Consecutive patients who underwent CAS were retrospectively enrolled (n = 456). At the end of 3 years of follow-up, patients who had died or were lost follow-up were excluded from the study and a final analysis was performed using data from the remaining 405 patients. The study population (n = 405) was divided into 3 tertiles based on the tertile values of the eGFR level (T1, T2, and T3); then, clinical and procedural characteristics and 3-year ISR rates were compared between the groups. An ISR of 50% was detected in 49 (12%) surviving patients. The 3-year ISR was higher among patients with the lowest eGFR values (T1) by 3.7 times (95% CI: 2.01-11.38) than that among patients with the highest eGFR values (T3). These significant relationships persisted following adjustment for confounders. A lower baseline eGFR level was significantly associated with an increased ISR rate. Decreased renal function may be a predictor of ISR after CAS using first-generation stents.

Risk Factors for Restenosis After Carotid Revascularization: A Meta-Analysis of Hazard Ratios

BACKGROUND

Carotid artery restenosis after carotid endarterectomy (CEA) or carotid artery stenting (CAS) will occur in 3%-30% of cases. Restenosis can lead to more frequent clinical and imaging monitoring and the potential for reoperation. We sought to define the demographic, clinical, and radiographic characteristics that influence the restenosis risk after carotid revascularization.

METHODS

The present study was performed in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. A random effects model meta-analysis of hazard ratios (HRs) was conducted.

RESULTS

Eighteen studies with 17,106 patients were included. Diabetes (HR, 1.68; 95% confidence interval [CI], 1.00-2.83; I², 76.7%), dyslipidemia (HR, 1.77; 95% CI, 1.08-2.91; I², 22.5%), female gender (HR, 1.50; 95% CI, 1.14-1.98, I², 0%), chronic kidney disease (HR, 4.15; 95% CI, 1.69-10.19; I², 44.5%), hypertension (HR, 1.99; 95% CI, 1.07-3.72; I², 68%), smoking (HR, 1.65; 95% CI, 1.15-2.37; I², 54.3%), and pretreatment stenosis >70% (HR, 1.04; 95% CI, 1.0-1.08; I², 0%) showed a statistically significant increase in restenosis risk after carotid revascularization. Subgroup analyses of CEA and CAS showed that female gender and smoking status were significantly associated with recurrent stenosis after CEA but not after CAS. In contrast, hypertension was associated with restenosis after CAS but not after CEA. Patch endarterectomy (HR, 0.33; 95% CI, 0.22-0.50; I², 0%) and symptomatic status at presentation in the CAS group (HR, 0.61; 95% CI, 0.41-0.90; I², 0%) were associated with a decreased risk of restenosis. Antiplatelet use and coronary artery disease were not associated with restenosis risk.

CONCLUSIONS

Diabetes, dyslipidemia, female gender, renal failure, hypertension, and smoking were associated with an increased risk of restenosis, and patch endarterectomy and symptomatic status at presentation were associated with a decreased risk of carotid restenosis. Both female gender and current smoking status were only associated with recurrent stenosis after CEA, and hypertension was only associated with restenosis after CAS.

Influence of stenting with open-cell stents vs close-cell stents on the outcomes of patients with bilateral carotid stenosis

BACKGROUND

Carotid artery stenting (CAS) is an effective way to prevent stroke in patients with severe carotid stenosis. However, several studies comparing the outcomes of stenting with open-cell stents (OCS) vs closed-cell stents (CCS) have yielded inconclusive results. This study aimed to compare the outcomes of CAS with OCS vs CCS in the same patients.

METHODS

From year 2000 to 2016, we included 52 patients with severe bilateral carotid stenosis who underwent OCS deployment in one artery and CCS deployment in the contralateral artery. Stents were selected according to arterial anatomy and lesion morphology, and the peri-procedural and long-term outcomes of treatment with OCS vs CCS, were compared in terms of rates of ischemic spot development on early post-procedural diffusion-weighted imaging (ISDWI), in-stent restenosis (ISR), and recurrent stroke.

RESULTS

After stenting with OCS vs CCS, the number (rate) of arteries with no lesion, < 5 lesions, and ≥ 5 lesions on DWI was 9 (32%) vs 8 (27%), 8 (29%) vs 17 (57%), and 11 (39%) vs 5 (17%) (p = .10); number (rate) of arteries with 0%, < 50%, and >50% ISR was 34 (65%) vs 34 (65%), 9 (17%) vs 11 (21%), and 9 (17%) vs 7 (13%) (p = .71); number (rate) of recurrent strokes after CAS was 2 (4%) vs 0 (0%).

CONCLUSION

The rates of peri-procedural cerebral ischemic insult, long-term stent patency, and stroke recurrence indicate that no one carotid stent cell design is superior to the other. We suggest both OCS and CCS are reasonable options for the treatment of severe carotid stenosis.

Enabling Angioplasty-Ready "Smart" Stents to Detect In-Stent Restenosis and Occlusion

Despite the multitude of stents implanted annually worldwide, the most common complication called in-stent restenosis still poses a significant risk to patients. Here, a "smart" stent equipped with microscale sensors and wireless interface is developed to enable continuous monitoring of restenosis through the implanted stent. This electrically active stent functions as a radiofrequency wireless pressure transducer to track local hemodynamic changes upon a renarrowing condition. The smart stent is devised and constructed to fulfill both engineering and clinical requirements while proving its compatibility with the standard angioplasty procedure. Prototypes pass testing through assembly on balloon catheters withstanding crimping forces of >100 N and balloon expansion pressure up to 16 atm, and show wireless sensing with a resolution of 12.4 mmHg. In a swine model, this device demonstrates wireless detection of blood clot formation, as well as real-time tracking of local blood pressure change over a range of 108 mmHg that well covers the range involved in human. The demonstrated results are expected to greatly advance smart stent technology toward its clinical practice.

Continuous daily use of cilostazol prevents in-stent restenosis following carotid artery stenting: serial angiographic investigation of 229 lesions

BACKGROUND

Several studies have reported that cilostazol (CLS) may reduce in-stent restenosis (ISR) after carotid artery stenting (CAS). However, it is not known for how long CLS must be continued to prevent ISR.

METHODS

We retrospectively reviewed a prospectively collected database of patients who underwent elective CAS and follow-up angiography at 3 months and 1 year after the procedure. ISR was defined as stenosis of 50% or greater on digital subtraction angiography. The cumulative incidence rates of angiographic ISR were compared between the three groups, divided according to duration of CLS use : (1) patients who were maintained on CLS for 12 months or more after CAS (12M CLS group, n=70), (2) patients who were treated with CLS for the first 3 months after CAS (3M CLS group, n=23), and (3) patients who did not receive CLS (no CLS group, n=136).

RESULTS

A total of 229 lesions in 199 patients were included in our analysis. During a median follow-up of 365 days, ISR was detected in 15 lesions. The cumulative ISR rates overall and in the 12M CLS, 3M CLS, and no CLS groups were 5.6%, 0%, 5.0%, and 8.4%, respectively, at 1 year, and the log rank test showed that there was a significant difference between the three groups (p<0.05). Cox regression analysis demonstrated that the 12M CLS group had a significantly lower risk of ISR than the 3M CLS group (adjusted relative risk (aRR) 3.06e-10, 95% CI 0 to 0.51, p<0.05) and the no CLS group (aRR 1.41e-10, 95% CI 0 to 0.15, p<0.001), whereas no difference was found between the 3M CLS group and the no CLS group.

CONCLUSIONS

An overall cumulative ISR rate of 5.6% was documented angiographically at 1 year after CAS. Continuous daily use of CLS (for at least 1 year) may have a beneficial effect on long term prevention of ISR.

Analysis of restenosis after carotid artery stenting: preliminary results using computational fluid dynamics based on three-dimensional angiography

Currently carotid artery stenting (CAS) is a widely used technique for the treatment of carotid artery stenosis. However, some patients with restenosis following CAS have been reported, resulting in potential clinical problems. The purpose of this study was to investigate the hemodynamic changes before and after CAS to find the factors that may influence restenosis. Five patients (two with restenosis, three without restenosis) were included in this study. The geometry and rheological conditions of the carotid arteries were obtained from three-dimensional digital subtraction angiography and ultrasound measurements. Computational fluid dynamics (CFD) modelling was performed to calculate wall shear stress (WSS), wall shear stress gradient (WSSG) and internal carotid artery (ICA) flow ratio. In addition, morphologic analysis was carried out. CFD results indicated that the WSSG of the restenosis group was significantly larger than that of the no-restenosis group. In the restenosis group, the WSS distribution after CAS showed a significant variation at the ICA. The average ICA flow ratio of the restenosis group was 43.5%, while in the no-restenosis group it was 68.6%. Furthermore, there were similar significant differences between the two groups during morphology analysis. CFD technology is useful for physicians in estimating haemodynamic changes during ICA stenosis treatment. These parameters, including ICA flow ratio and WSS distribution, may help to predict carotid restenosis. In future, CFD combined with other medical techniques such as digital subtraction angiography, MRI and pathology technologies will be available for the clinical estimation of ICA restenosis.