OBJECTIVE: Hemodynamically relevant internal carotid artery (ICA) stenosis is a major cause of ischemic stroke. Despite its long-term benefit, carotid endarterectomy may also be associated with severe neurologic deficits. Intraoperative and early recognition of ischemia in the region of the ICA may reduce this risk. To date, direct imaging and quantitative analysis of microvascular structures and function in the human ICA region have not been possible. We purposed to visualize and quantify ischemia/reperfusion-induced microcirculatory changes in the terminal vascular bed of the ICA in patients undergoing unilateral ICA endarterectomy. METHODS: Sequential analysis of the ipsilateral and contralateral conjunctival microcirculation was performed with orthogonal polarized spectral imaging in 33 patients undergoing unilateral ICA endarterectomy because of moderate or severe ICA stenosis (North American Symptomatic Carotid Endarterectomy Trial score, 75% +/- 13%), before clamping the ICA (baseline), during clamping of the external carotid artery and ICA, during reperfusion of the ICA (intraluminal shunt), during the second clamping of the ICA (shunt removal), after declamping (reperfusion) of the external carotid artery and ICA, and 15 to 20 minutes after the second ICA reperfusion. RESULTS: During ICA clamping for shunt placement, ipsilateral and contralateral conjunctival capillary perfusion was significantly decreased, but it was completely restored after reperfusion with carotid shunting. Reclamping of the ICA for shunt removal caused microvascular dysfunction, which was significantly less pronounced than that observed during the first clamping. The individual degree of ICA stenosis was inversely correlated with the ipsilateral and contralateral decrease in conjunctival functional capillary density during the first ICA clamping. CONCLUSIONS: These results suggest adaptive mechanisms of capillary perfusion with increasing stenosis and development of collateral compensatory circulation in the vascular region of the human ICA. Conjunctival orthogonal polarized spectral imaging during unilateral ICA reconstruction enables continuous noninvasive analysis of bilateral conjunctival microcirculation in the terminal region of the ICA and enables monitoring for efficient carotid shunt perfusion during and after endarterectomy.
OBJECTIVE: Hemodynamically relevant internal carotid artery (ICA) stenosis is a major cause of ischemic stroke. Despite its long-term benefit, carotid endarterectomy may also be associated with severe neurologic deficits. Intraoperative and early recognition of ischemia in the region of the ICA may reduce this risk. To date, direct imaging and quantitative analysis of microvascular structures and function in the human ICA region have not been possible. We purposed to visualize and quantify ischemia/reperfusion-induced microcirculatory changes in the terminal vascular bed of the ICA in patients undergoing unilateral ICA endarterectomy. METHODS: Sequential analysis of the ipsilateral and contralateral conjunctival microcirculation was performed with orthogonal polarized spectral imaging in 33 patients undergoing unilateral ICA endarterectomy because of moderate or severe ICA stenosis (North American Symptomatic Carotid Endarterectomy Trial score, 75% +/- 13%), before clamping the ICA (baseline), during clamping of the external carotid artery and ICA, during reperfusion of the ICA (intraluminal shunt), during the second clamping of the ICA (shunt removal), after declamping (reperfusion) of the external carotid artery and ICA, and 15 to 20 minutes after the second ICA reperfusion. RESULTS: During ICA clamping for shunt placement, ipsilateral and contralateral conjunctival capillary perfusion was significantly decreased, but it was completely restored after reperfusion with carotid shunting. Reclamping of the ICA for shunt removal caused microvascular dysfunction, which was significantly less pronounced than that observed during the first clamping. The individual degree of ICA stenosis was inversely correlated with the ipsilateral and contralateral decrease in conjunctival functional capillary density during the first ICA clamping. CONCLUSIONS: These results suggest adaptive mechanisms of capillary perfusion with increasing stenosis and development of collateral compensatory circulation in the vascular region of the human ICA. Conjunctival orthogonal polarized spectral imaging during unilateral ICA reconstruction enables continuous noninvasive analysis of bilateral conjunctival microcirculation in the terminal region of the ICA and enables monitoring for efficient carotid shunt perfusion during and after endarterectomy.
Authors: Daniel De Backer; Gustavo Ospina-Tascon; Diamantino Salgado; Raphaël Favory; Jacques Creteur; Jean-Louis Vincent Journal: Intensive Care Med Date: 2010-08-06 Impact factor: 17.440
Authors: Ali Kord Valeshabad; Justin Wanek; Faisal Mukarram; Ruth Zelkha; Fernando D Testai; Mahnaz Shahidi Journal: Microvasc Res Date: 2015-04-24 Impact factor: 3.514
Authors: Vassilios P Kozobolis; Efstathios T Detorakis; George S Georgiadis; Athanassios A Achtaropoulos; Theofanis T Papas; Miltos K Lazarides Journal: Graefes Arch Clin Exp Ophthalmol Date: 2007-04-25 Impact factor: 3.117
Authors: Maziyar M Khansari; Justin Wanek; Anthony E Felder; Nicole Camardo; Mahnaz Shahidi Journal: IEEE Trans Med Imaging Date: 2015-10-06 Impact factor: 10.048