Sally A. McCoy

Ultrasound criteria for severe in-stent restenosis following carotid artery stenting

PURPOSE In-stent restenosis (ISR) is a known complication following carotid artery stenting (CAS). However, ultrasound criteria determining ISR are not well established. We evaluated alternative ultrasound velocity criteria for >70% ISR in our institution. METHODS Clinical records of 256 patients undergoing 282 consecutive CAS procedures over a 42-month period were reviewed. Follow-up ultrasounds were available for analysis in 237 patients. Selective angiograms and repeat interventions were performed for >70% ISR. Ultrasound criteria including peak systolic velocity (PSV), end diastolic velocity (EDV), and internal carotid to common carotid artery ratios (ICA/CCA) were examined. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PSV (200, 250, 300, 350, and 400 cm/s), EDV (70, 80, 90, 100 cm/s), and CCA/ICA (3, 3.5, 4, 4.5, 5). RESULTS Twenty-two carotid angiograms were performed and 18 lesions had confirmations of >70% ISR in 11 patients including prior CEA in five patients and neck irradiation in two patients. Receiver operator characteristics (ROC) was analyzed for PSV, EDV, and CCA/ICA ratio. For 70% or greater angiographic ISR, PSV > 300 cm/s correlated to a 94% sensitivity, 50% specificity, 90% positive predictive value (PPV), and 67% negative predictive value (NPV); EDV > 90 cm/s correlated to an 89% sensitivity, 100% specificity, 100% PPV, and 67% NPV; and ICA/CCA > 4 had a 94.4% sensitivity, 75% specificity, 94% PPV, and 75% NPV. A significant color flow disturbance was detected in one patient who did not meet the aforementioned ultrasound velocity criteria. Further statistical analysis showed that an EDV of 90 cm/s provided the best discriminant value. CONCLUSION Our study demonstrated that PSV > 300 cm/s, EDV > 90 cm/s, and ICA/CCA > 4 correlated well with >70% ISR. Although still rudimentary, these velocity criteria combined with color flow patterns can reliably predict severe ISR in our vascular laboratory. However, due to the relatively infrequent cases of severe ISR following CAS, a multicentered study is warranted to establish standard post-CAS ultrasound surveillance criteria for severe ISR.

Carotid artery stenting with distal protection using the carotid wallstent and filterwire neuroprotection: single-center experience of 380 cases with midterm outcomes.

Emerging data have supported the clinical efficacy of carotid artery stenting (CAS) in stroke prevention in high-risk surgical patients. This study was performed to evaluate the midterm clinical outcome of CAS using the Carotid Wallstent and FilterWire distal protection (both Boston Scientific, Natick, MA) at an academic institution. Risk factors for in-stent restenosis (ISR) were also analyzed. Clinical variables and treatment outcome of high-risk patients who underwent Carotid Wallstent placement with FilterWire EX/EZ neuroprotection were analyzed during a recent 54-month period. Three hundred eighty CAS procedures were performed in 354 patients. Technical success was achieved in 372 cases (98%), and symptomatic lesions existed in 85 (24%) patients. No patient experienced periprocedural mortality or neuroprotective device–related complication. The 30-day stroke and death rate was 2.7%, and the overall complication rate was 6.9%. The overall major or fatal stroke rates in symptomatic and asymptomatic patients were 4.6% and 1.3%, respectively (not significant). The overall stroke and death rates between the symptomatic and asymptomatic groups were 5.8% and 2.4%, respectively (not significant). The median follow-up period was 29 months (range 1–53 months). With Kaplan-Meier analysis, the rates of freedom from 60% or greater ISR after CAS procedures at 12, 24, 36, and 48 months were 97%, 94%, 92%, and 90%, respectively. The rates of freedom from all fatal and nonfatal strokes at 12, 24, 36, and 48 months were 97%, 91%, 89%, and 85%, respectively. Multivariable analysis of significant univariate predictors identified that postendarterectomy stenosis (odds ratio [OR] 3.98, p = .02) and multiple stent placement (OR 3.68, p = .03) were independent predictors of ISR. Our study yielded favorable short-term and midterm clinical results using Carotid Wallstent with FilterWire neuroprotection. Late follow-up results showed low rates of fatal and nonfatal stroke and favorable ISR rates compared with other carotid stent trials. Postendarterectomy and multiple stent placement were associated with subsequent ISR.

Validating common carotid stenosis by duplex ultrasound with carotid angiogram or computed tomography scan

BACKGROUND No consensus exists for duplex ultrasound criteria in the diagnosis of significant common carotid artery (CCA) stenosis. In general, peak systolic velocity (PSV) >150 cm/s with poststenotic turbulence indicates a stenosis >50%. The purpose of our study is to correlate CCA duplex velocities with angiographic findings of significant stenosis >60%. METHODS We reviewed the carotid duplex records from 2008 to 2011 looking for patients with isolated CCA stenosis and no ipsilateral internal or contralateral carotid artery disease who received either a carotid angiogram or a computed tomography scan. We identified 25 patients who had significant CCA disease >60%. We also selected 74 controls without known CCA stenosis. We performed receiver operating characteristics analysis to correlate PSV and end-diastolic velocity (EDV) with angiographic stenosis >60%. The degree of stenosis was determined by measuring the luminal stenosis in comparison to the proximal normal CCA diameter. RESULTS Most patients had a carotid angiogram (21/25), four only had a computed tomography angiography and four had both. Eighteen patients had history of neck radiation. The CCA PSV ≥250 cm/s had a sensitivity of 98.7% (81.5%-100%) and a specificity of 95.7% (92.0%-99.9%), CCA PSV ≥300 cm/s had a sensitivity of 90.9% (69.4%-98.4%) and a specificity of 98.7% (92.0%-99.9%). The CCA EDV ≥40 cm/s had a sensitivity of 95.5% (95% confidence interval of 75.1-99.8%) and specificity of 98.7% (92.0%-99.9%), EDV ≥60 cm/s had a sensitivity of 100% (75.1%-99.8%) and specificity of 87% (94.1-100%), and EDV ≥70 cm/s had a sensitivity of 86.4% (64.0%-96.4%) and specificity of 100% (94.1%-100%). The presence of both PSV <250 cm/s and EDV <60 cm/s had a 98.7% negative predictive value, and the presence of both PSV ≥250 cm/s and EDV ≥60 cm/s had 100% positive predictive value. CONCLUSIONS Establishing CCA duplex criteria to screen patients with significant stenosis is crucial to identify those who will need further imaging modality or treatment. In our laboratory, CCA PSV ≥250 cm/s and EDV ≥60 cm/s are thresholds that can be used to identify significant (>60%) CCA stenosis with a high degree of accuracy.