Inraoperative and Histological Visualization of Disrupted Vulnerable Plaques following Diagnostic Angiography of Moderate Carotid Stenosis

SAGE-Hindawi Access to Research Stroke Research and Treatment Volume 2010, Article ID 602642, 5 pages doi:10.4061/2010/602642 Case Report Inraoperative and Histological Visualization of Disrupted Vulnerable Plaques following Diagnostic Angiography of Moderate Carotid Stenosis Tatsushi Mutoh,1, 2 Tatsuya Ishikawa,2 Akifumi Suzuki,1 and Nobuyuki Yasui2 1 Department of Stroke Science, Research Institute for Brain and Blood Vessels-Akita, Akita 010-0874, Japan 2 Department of Surgical Neurology, Research Institute for Brain and Blood Vessels-Akita, Akita 010-0874, Japan Correspondence should be addressed to Tatsushi Mutoh, Received 18 August 2009; Accepted 29 October 2009 Academic Editor: Turgut Tatlisumak Copyright © 2010 Tatsushi Mutoh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Digital subtraction angiography (DSA) remains an important tool for diagnosis of carotid stenosis but is associated with risk for periprocedural complications. This is the first report of direct intraoperative and histolopathologic visualization of DSA-related carotid plaque disruption. Case. A 64-year-old man diagnosed to have a 60% right carotid stenosis received diagnostic DSA for therapeutic decision-making. He developed transient left hand numbness and weakness immediately after the procedure. Intraoperative imaging during carotid endarterectomy revealed a fragile plaque with sharp surface laceration and intraplaque hemorrhage at the bifurcation. Microscopy of the specimen demonstrated a large atheromatous plaque with fibrous hypertrophy and intraplaque hemorrhage filled with recent hemorrhagic debris. Conclusion. The visualized carotid lesion was more serious than expected, warning the danger of embolization or occlusion associated with the catheter maneuvers. Thus the highest level of practitioner training and technical expertise that ensures precise assessment of plaque characteristics should be encouraged. 1. Introduction Despite recent advances in minimally invasive imaging techniques for carotid vessels like Doppler ultrasonography (US), MR angiography (MRA), and CT angiography (CTA), digital subtraction angiography (DSA) provides the highest spatial resolution and still remains the “gold standard” for diagnosis of carotid artery stenosis, but it is associated with risk for procedure-related neurologic complications. In fact, therapeutic decisions in large clinical trials [1–4] have been based on maximal internal carotid artery (ICA) stenosis depicted with conventional DSA. It is well known that vulnerable carotid plaque is an atheromatous plaque that is particularly prone to disruption, fracture, or fissuring with a higher risk for embolization, occlusion, and consequent ischemic neurological events [5]. Although disruption of such unstable plaques has been commonly implicated as a risk for procedure-related neurological complications in patients undergoing DSA, most resultant stroke events are clinically silent or transient [6, 7], and there are few descriptions of the affected vessel walls. We report a case of direct visualization and histolopathologic examination of carotid plaque disruption associated with the diagnostic DSA for therapeutic consideration of asymptomatic moderate-grade carotid stenosis, which was incidentally detected later during carotid endarterectomy (CEA). 2. Case Report A 64-year-old man with past medical history of hypertension, type 2 diabetes mellitus, hypercholesterolemia, and symptomatic ischemic stroke in the territory of the thalamoperforate artery diagnosed to have an asymptomatic moderate (approximately 50%) right ICA stenosis that was observed on MRA was referred to our center for consideration of surgical intervention. Carotid Doppler ultrasonography demonstrated hypoechoic plaques with 2 an irregular surface at the carotid bifurcation extending to the proximal ICA with stenosis of 83% (by area method) and peak systolic flow velocity at 1.89 m/s (Figures 1(a) and 1(b)). Resting single photon emission CT (SPECT) showed severe hypoperfusion in the right ICA territory (Figure 1(c)), presumably due to less prevalence of collateral flow via the anterior or posterior communicating artery (Figures 1(d) and 1(e)) [8]. For therapeutic decision-making, diagnostic carotid angiography was then performed via a femoral approach. It was difficult to cannulate a 5-Fr. JB-2 catheter (Cook, Bloomington, IN) over an angled 0.035 inch Radifocus guidewire (Terumo, Tokyo, Japan) selectively advanced into the right common carotid artery (CCA). The procedure was repeated with a 5-Fr. Simmons II catheter (Cook, Bloomington, IN) but failed to engage in the CCA due to severe vascular elongation. Therefore, the guidewire was advanced carefully, with special attention not to cross the stenotic lesion at the proximal ICA, into the lingual branch of the external carotid artery (ECA) for support, and the catheter was successfully advanced to the CCA. The DSA revealed a 60% stenosis of the proximal right ICA with wall irregularities (Figure 2(a)), calculated according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method [2]. The contralateral carotid angiogram demonstrated a mild stenosis in the posterior wall of the ICA. Vertebral angiography was discontinued as it was difficult to probe the bilateral vessels due to elongation. The patient developed numbness and mild weakness of the left hand immediately after the procedure. Diffusionweighted MR imaging showed multiple, small hyperintense lesions in the distal ICA territory of the right front-parietal lobe indicative of an embolic origin from the carotid plaques (Figure 2(c)). The symptoms were transient and resolved within 24 hours of the procedure with supplemental intravenous fluids followed by oral clopidogrel (Plavix, Sanofi Pharmaceuticals, New York, NY) 75 mg once daily. Based on the results of the Asymptomatic Carotid Atherosclerosis Study (ACAS) [1] and the Medical Council Asymptomatic Carotid Surgery Trial (ACST) [4], the patient is considered to be a good candidate for elective surgery and given informed consent about CEA. Two weeks later, the patient underwent successful right CEA. Fragile atherosclerotic plaque with sharp surface laceration, somewhat different from atheromatous plaque rupture, accompanied by intraplaque hemorrhage was observed at the proximal ICA close to the bifurcation (Figures 3(a) and 3(b)). There was no evidence of perforation outside the wall. Microscopic examination of the endarterectomy specimen revealed a large atheromatous plaque with fibrous hypertrophy and intraplaque hemorrhage filled with recent hemorrhagic debris that stained red to brown with ElasticaMasson stain, cholesterol crystal formation, and speckled calcification (Figure 3(c)). The postoperative course was unevent (...truncated)