Echographic Risk Index and Cerebral Ischemic Brain Lesions in Patients Randomized to Stenting versus Endarterectomy for Symptomatic Carotid Artery Stenosis

Abstract

Purpose: It remains to be determined whether the impact of plaque characteristics on procedural risks differs between carotid artery stenting (CAS) and endarterectomy (CEA). We studied whether quantitative assessment of carotid plaque echolucency on ultrasound predicts the risk of embolism during CAS or CEA.

Materials and Methods: In 50 consecutive patients with symptomatic carotid stenosis randomized to CAS (n = 26) or CEA (n = 24) in the International Carotid Stenting Study (ICSS), semi-automated grayscale measurement of carotid plaques on baseline ultrasound was performed. We determined the grayscale median (GSM), percentage of echolucent plaque area, and a previously defined echographic risk index (ERI) calculated with the echolucent area and degree of stenosis. Brain MRI including diffusion-weighted imaging (DWI) was performed within 7 days before and 3 days after treatment. The primary outcome was the presence of at least 1 new hyperintense DWI lesion (DWI+) after treatment.

Results: In the CAS group, DWI+ patients (n = 18) had a significantly higher ERI at baseline (mean 0.11 ± 0.12) than patients without new lesions (n = 8; mean 0.03 ± 0.01; p = 0.012). GSM (mean 26.7 ± 18.7 versus 34.3 ± 8.0, p = 0.16) and echolucent plaque area (mean 42.8 ± 21.1 versus 31.2 ± 8.2, p = 0.054) did not differ significantly. In the CEA group, there were no differences in plaque echogenity measurements between patients with (n = 2) and without DWI lesions (n = 22).

Conclusion: Patients with echolucent plaques causing severe narrowing are at increased risk for cerebral embolism during CAS. Quantitative ultrasound plaque analysis, with ERI in particular, may add to clinical variables in identifying patients at risk for procedural stroke with CAS, but larger studies with clinical endpoints are needed.

Zusammenfassung

Ziel: Plaqueeigenschaften beeinflussen das Risiko periprozeduraler Embolien während Stent-Angioplastie (CAS) und Endarterektomie (CEA). Es ist unklar, ob sich dieser Einfluss zwischen CAS und CEA unterscheidet. Wir haben untersucht, ob die quantitative Bestimmung der Plaque-Echogenität die Embolierate während CAS oder CEA vorhersagt.

Material und Methoden: Wir untersuchten 50 ICSS randomisierte CAS oder CEA Patienten mit semi-automatischen ultraschallgestützten Graustufenmessungen von Karotisplaques. Bestimmt wurden Graustufen-Median (GSM), Prozent der echoluzenten Plaqueanteile, sowie ein echografischer Risikoindex (ERI). Zerebrale Kernspintomografien inklusive DWI-Sequenzen wurden vor und nach Behandlung durchgeführt. Als primärer Endpunkt galt mindestens eine neue hyperintense DWI-Läsion (DWI+).

Ergebnisse: Innerhalb der CAS-Gruppe zeigten DWI+ Patienten (n = 18) signifikant höhere ERI-Werte (Mittelwert 0,11 ± 0,12) im Vergleich zu Patienten ohne Läsionen (DWI−; n = 8; 0,03 ± 0,01; p = 0,012). GSM (26,7 ± 18,7 versus 34,3 ± 8,0, p = 0,16) und hypoechogene Plaqueanteile (42,8 ± 21,1 versus 31,2 ± 8,2, p = 0,054) zeigten keine signifikanten Unterschiede. In der CEA-Gruppe bestanden keine Unterschiede in der Plaqueechogenität zwischen DWI+ (n = 2) und DWI− Patienten (n = 22).

Schlussfolgerung: Patienten mit echoluzenten Plaques und höhergradiger Stenose tragen ein erhöhtes Risiko cerebraler Embolien während CAS. Die quantitative ultraschallgestützte Plaqueanalyse liefert Anhaltspunkte zur Identifizierung von Patienten, die ungeeignet für CAS sind.

Key words

carotid stenosis - plaque echolucency - stenting - endarterectomy - embolism

• References

• 1 Barnett HJ, Taylor DW, Eliasziw M et al. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med 1998; 339: 1415-1425
• 2 European Carotid Surgery Trialists’ Collaborative Group. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: Final results of the MRC European Carotid Surgery Trial (ECST). The Lancet 1998; 351: 1379-1387
• 3 Bonati LH, Lyrer P, Ederle J et al. Percutaneous transluminal balloon angioplasty and stenting for carotid artery stenosis. Cochrane Database Syst Rev 2012; CD000515 9
• 4 Bonati LH, Dobson J, Algra A et al. Short-term outcome after stenting versus endarterectomy for symptomatic carotid stenosis: a preplanned meta-analysis of individual patient data. Lancet 2010; 376: 1062-1073
• 5 Aburahma AF, Thiele SP, Wulu JT et al. Prospective controlled study of the natural history of asymptomatic 60% to 69% carotid stenosis according to ultrasonic plaque morphology. J Vasc Surg 2002; 36: 437-442
• 6 Eyding J, Geier B, Staub D. Current strategies and possible perspectives of ultrasonic risk stratification of ischemic stroke in internal carotid artery disease. Ultraschall in Med 2011; 32: 267-273
• 7 Gray-Weale AC, Graham JC, Burnett JR et al. Carotid artery atheroma: comparison of preoperative B-mode ultrasound appearance with carotid endarterectomy specimen pathology. J Cardiovasc Surg (Torino) 1988; 29: 676-681
• 8 Biasi GM, Sampaolo A, Mingazzini P et al. Computer analysis of ultrasonic plaque echolucency in identifying high risk carotid bifurcation lesions. Eur J Vasc Endovasc Surg 1999; 17: 476-479
• 9 Sabetai MM, Tegos TJ, Clifford C et al. Carotid plaque echogenicity and types of silent CT-brain infarcts. Is there an association in patients with asymptomatic carotid stenosis?. Int Angiol 2001; 20: 51-57
• 10 Gronholdt ML, Nordestgaard BG, Schroeder TV et al. Ultrasonic echolucent carotid plaques predict future strokes. Circulation 2001; 104: 68-73
• 11 el-Barghouty N, Geroulakos G, Nicolaides A et al. Computer-assisted carotid plaque characterisation. Eur J Vasc Endovasc Surg 1995; 9: 389-393
• 12 Tegos TJ, Sabetai MM, Nicolaides AN et al. Comparability of the ultrasonic tissue characteristics of carotid plaques. J Ultrasound Med 2000; 19: 399-407
• 13 Mathiesen EB, Bonaa KH, Joakimsen O. Echolucent plaques are associated with high risk of ischemic cerebrovascular events in carotid stenosis: the tromso study. Circulation 2001; 103: 2171-2175
• 14 Momjian-Mayor I. Accuracy of a Novel Risk index Combining Degree of Stenosis of the Carotid Artery and Plaque Surface Echogenicity. Stroke 2012;
• 15 Ederle J, Dobson J, Featherstone RL et al. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial. Lancet 2010; 375: 985-997
• 16 Bonati LH, Jongen LM, Haller S et al. New ischaemic brain lesions on MRI after stenting or endarterectomy for symptomatic carotid stenosis: a substudy of the International Carotid Stenting Study (ICSS). Lancet Neurol 2010; 9: 353-362
• 17 Featherstone RL, Brown MM, Coward LJ. International carotid stenting study: protocol for a randomised clinical trial comparing carotid stenting with endarterectomy in symptomatic carotid artery stenosis. Cerebrovasc Dis 2004; 18: 69-74
• 18 Sztajzel R, Momjian S, Momjian-Mayor I et al. Stratified gray-scale median analysis and color mapping of the carotid plaque: correlation with endarterectomy specimen histology of 28 patients. Stroke 2005; 36: 741-745
• 19 Sztajzel R, Momjian-Mayor I, Comelli M et al. Correlation of cerebrovascular symptoms and microembolic signals with the stratified gray-scale median analysis and color mapping of the carotid plaque. Stroke 2006; 37: 824-829
• 20 Momjian I, Momjian S, Albanese S et al. Visual analysis or semi-automated gray-scale-based color mapping of the carotid plaque: which method correlates the best with the presence of cerebrovascular symptoms and/or lesions on MRI?. J Neuroimaging 2009; 19: 119-126
• 21 Carotid artery plaque composition--relationship to clinical presentation and ultrasound B-mode imaging. European Carotid Plaque Study Group. Eur J Vasc Endovasc Surg 1995; 10: 23-30
• 22 Biasi GM, Froio A, Diethrich EB et al. Carotid plaque echolucency increases the risk of stroke in carotid stenting: the Imaging in Carotid Angioplasty and Risk of Stroke (ICAROS) study. Circulation 2004; 110: 756-762
• 23 Rosenkranz M, Russjan A, Goebell E et al. Carotid plaque surface irregularity predicts cerebral embolism during carotid artery stenting. Cerebrovasc Dis 2011; 32: 163-169
• 24 Staub D, Partovi S, Imfeld S et al. Novel applications of contrast-enhanced ultrasound imaging in vascular medicine. Vasa 2013; 42: 17-31
• 25 Bamber J, Cosgrove D, Dietrich CF et al. EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 1: Basic principles and technology. Ultraschall in Med 2013; 34: 169-184
• 26 Cosgrove D, Piscaglia F, Bamber J et al. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography.Part 2: Clinical Applications. Ultraschall in Med 2013; 34: 238-253
• 27 Maurice RL, Soulez G, Giroux MF et al. Noninvasive vascular elastography for carotid artery characterization on subjects without previous history of atherosclerosis. Med Phys 2008; 35: 3436-3443
• 28 Schnaudigel S, Groschel K, Pilgram SM et al. New brain lesions after carotid stenting versus carotid endarterectomy: a systematic review of the literature. Stroke 2008; 39: 1911-1919
• 29 Gensicke H, Zumbrunn T, Jongen LM et al. Characteristics of ischemic brain lesions after stenting or endarterectomy for symptomatic carotid artery stenosis: results from the international carotid stenting study-magnetic resonance imaging substudy. Stroke 2013; 44: 80-86