Predictors of Carotid Clamping Intolerance during Endarterectomy That Would Be Wise to Apply to Stenting Procedures

Abstract

Background and Purpose: Carotid artery stenting procedures are increasingly being performed with devices such as the MO.MA or the Parodi system that involve endovascular clamping of the common carotid artery, thus exposing the ipsilateral hemisphere to the risk of hypoperfusion. The aim of the present study was to look for predictors of carotid clamping intolerance by means of transcranial Doppler. Patients and Methods: We analysed the findings of an earlier Italian multicentre prospective study (SCITEA, Italian Cooperative Study of Transcranial Doppler in Carotid Endarterectomy) in which 513 consecutive patients (males/females 397/116, mean age 67 ± 7 years, mean carotid stenosis 81 ± 11%, NASCET method) scheduled to undergo carotid endarterectomy had been investigated non-invasively with transcranial Doppler, and we correlated the data obtained preoperatively with the need to insert a shunt during surgery as an index of intolerance to carotid clamping. Results: Four hundred and thirty-nine patients (85.6%) underwent surgery without and 74 (14.4%) with the insertion of a shunt. Patients who needed a shunt (intolerant) had a significantly higher decrement in mean flow velocity in the ipsilateral middle cerebral artery (MCA) after compression of the ipsilateral common carotid artery (71.8 ± 22 vs. 30.6 ± 24%) and were significantly more likely to have non-recruitable collateral pathways (75 vs. 18%). Logistic regression analysis confirmed that an MCA decrement of >85% (p = 0.005) and no potential collateralization (p = 0.011) were independent predictors of clamping intolerance. Combining the results of both compression tests (MCA decrement and collateral recruitment) yielded a sensitivity of 64%, a specificity of 99%, a positive predicted value of 88%, a negative predicted value of 95% and an overall accuracy of 95% in predicting shunt insertion. Conclusions: The preoperative assessment of recruitable collaterals and of maximal decrement in MCA mean flow velocity after carotid compression are useful predictors of carotid clamping intolerance. The criteria derived from carotid endarterectomy need to be applied and validated in a prospective series of patients undergoing carotid artery stenting procedures.

Simultaneous Bilateral Carotid Stenting in High-Risk Patients

“…Although bilateral carotid stenosis has been shown to potentially increase the risk for complications during CEA or CAS and has been included as 1 of the high risks for CEA, our data revealed that there was no significant difference in outcome at 30 days or at 6 months between the bilateral and unilateral stent-placement patient groups. 1,10,[29][30][31] Although the outcome at 6 months did not reveal a significant difference in our study, the incidence of HPS in the SB-CAS group was higher than that in the unilateral stent-placement group (P ϭ .036). One characteristic difference we observed in our study was the onset of HPS, because 2 of 4 patients developed it 11 days and 3 weeks, respectively, after SBCAS in contrast to all 5 patients who developed HPS within 1 day following the stent placement procedure in the unilateral stent placement group.…”

Evaluation of Cerebrovascular Reserve in Patients Undergoing Carotid Artery Stenting and Its Usefulness in Predicting Significant Hemodynamic Changes During Temporary Carotid Occlusion

“…Following breath-holding test, the direction of flow in both ophthalmic arteries at an insonation depth of 50±5 mm was obtained, with flow direction away from the probe (flow reversal) considered abnormal and suggestive of depleted CVR. With regard to the previously published values defining normal BHI range (Zavoreo and Demarin 2004, Jimenez-Caballero and Segura 2006, Bago-Rozankovic et al 2009, Barret et al 2001) and in accordance with our observation derived from the control group, we arbitrarily defined the cut-off values for impaired BHI as <0.95 and as completely depleted in the case of BHI <0.69 as reported by Vernieri et al (1999).…”

“…Several authors have tried to estimate the role of pre-procedural TCD to detect severe hemodynamic changes during temporary carotid occlusion. Interestingly, it has been suggested that a pre-procedural carotid compression test might be useful in determining the patients who would tolerate carotid occlusion well (Anzola et al 2008). This test, however, carries a risk of stroke due to mobilization of plaque content.…”

The Role of Neurosonology in the Diagnosis and Management of Patients with Carotid Artery Disease: A Review

“…Manual compression of the CCA during TCD examination has been used for the preinterventional assessment of individuals with >70% stenosis. Decrement of >85% of the ispilateral MCA blood flow and absence of collateralization were independent predictors of clamping intolerance, whereas combined, the two parameters yielded a sensitivity of 64%, specificity of 99%, positive predictive value of 88%, negative predictive value of 95%, and overall accuracy of 95% in predicting clamping intolerence . Others found a threshold of 60% reduction in the MFV of the MCA after carotid compression to predict the need for shunting during clamping .…”