Subclavian Carotid Bypass of Occluded Common and Internal Carotid Arteries Facilitated by an Anomalous Branch of the Internal Carotid Artery Ryan Shields,1 Mitchell R. Ladd,2 Nishant Patel,2 and Thomas Reifsnyder,2 Baltimore, Maryland
Typically, internal carotid artery (ICA) occlusion precludes carotid endarterectomy. Extracranial branches of the ICA are uncommon. If this anomaly occurs in the setting of total proximal ICA occlusion then revascularization is feasible. We describe a unique example of such a case.
Typically, internal carotid artery (ICA) occlusion precludes carotid endarterectomy. At the time of occlusion, thrombus extends up to the origin of the ophthalmic artery rendering the extracranial ICA unsuitable for reconstruction.1 Uncommonly, there is an extracranial branch of the ICA. If this anomaly occurs in the setting of total proximal ICA occlusion then revascularization is feasible. An example of such a case is presented here.
CASE REPORT A 64-year-old man presented with a 4-month history of multiple episodes of near syncope and repetitive amaurosis fugax of the right eye. He was a heavy smoker despite having undergone chemotherapy and radiation for squamous cell carcinoma of the larynx 9 years earlier. A carotid duplex ultrasound showed occlusion of the right common carotid artery (CCA) and ICA, but did not identify a reconstituted ICA. In addition, the left ICA had a 50e69% stenosis and there was rapid antegrade flow in the vertebral arteries bilaterally. A computerized tomography arteriogram 1
Johns Hopkins School of Medicine, Baltimore, MD.
2
Department of General Surgery, Johns Hopkins Hospital, Baltimore, MD. Correspondence to: Thomas Reifsnyder, MD, Department of General Surgery, Johns Hopkins Hospital, 4940 Eastern Avenue, Building 5A-Center, Baltimore, MD 21224, USA; E-mail: [email protected] Ann Vasc Surg 2015; 29: 362.e1e362.e2 http://dx.doi.org/10.1016/j.avsg.2014.08.019 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: July 8, 2014; manuscript accepted: August 21, 2014; published online: November 13, 2014.
confirmed occlusion of the right CCA and proximal ICA, but revealed reconstitution of the distal cervical ICA at approximately the level of the C2 vertebra (Fig. 1). At this level, a small anomalous branch of the ICA was seen. Finally, the circle of Willis appeared patent. Because the patient was symptomatic, reconstruction via a subclavian carotid bypass was planned. Exposure of the carotid was through a standard incision anterior to the sternocleidomastoid muscle. The subclavian artery was exposed via a separate supraclavicular incision. The anomalous branch of the ICA was identified (Fig. 2) about 1.5 cm distal to the carotid bifurcation. A bypass was then performed using a nonreversed greater saphenous vein graft with the distal anastomosis performed in an end-to-end fashion to the ICA. Unfortunately, while preparing the ICA to perform the anastomosis, the anomalous branch was damaged and had to be ligated. The patient recovered uneventfully and was discharged the following day. Four months after surgery the patient remained asymptomatic.
DISCUSSION Anomalous branches of the ICA are relatively rare.2,3 They were first described in the mid 19th century by Hryltle and Quain.1,4,5 Quain specifically mentions an occipital branch of the ICA.5 A recent study by Small et al. demonstrated a 0.49% prevalence of an anomalous occipital artery and a 6.25% prevalence of a superior pharyngeal artery from the ICA, both rates greater than previously seen in the literature.3 Although rare, anomalous branches of the ICA have significant implications in the surgical treatment of atherosclerotic carotid artery disease because of the natural progression of 362.e1
362.e2 Case reports
Annals of Vascular Surgery
Fig. 1. (A) Computerized tomography arteriogram (CTA): arrows to occluded right CCA and proximal ICA. Arrow to reconstituted distal right ICA. (B) CTA: Arrows to reconstituted distal right ICA and anomalous branch generating the seen collateral flow.
occlusion to the next branch of the ICA. If an anomalous branch exists, retrograde flow either from this branch to the ICA or vice versa may maintain patency of the distal ICA. When this situation exists, then surgical intervention is still possible via a carotid endarterectomy or as in this case with a concomitant CCA occlusion, a subclavian-carotid artery bypass.1 Although this is not the first report of an anomalous branch maintaining distal patency of a proximally occluded ICA, it is the first such case that included an occluded CCA necessitating the use of a subclavian to carotid bypass to restore ICA flow. This case highlights a couple of important aspects in the treatment of carotid artery disease: the need to confirm occlusion of the ICA when seen by duplex scan and to carefully define the anatomy of each patient when deciding on the most appropriate operative approach. REFERENCES
Fig. 2. Intraoperative photography of right ICA approximately 1.5 cm distal to the carotid bifurcation (white vessel loop) and reconstituting anomalous branch presumed to be the occipital artery (blue vessel loop).
1. Bowen JC, Garcia M, Garrard CL, et al. Anomalous branch of the internal carotid artery maintains patency distal to a complete occlusion diagnosed by duplex scan. J Vasc Surg 1997;26:164e7. 2. Cortes-Franco S, Mu~ noz AL, Franco TC, et al. Anomalous ascending pharyngeal artery arising from the internal carotid artery: report of three cases. Ann Vasc Surg 2013;27:240. 3. Small JE, Harrington J, Watkins E. Prevalence of arterial branches arising from the extracranial internal carotid artery on CT angiography. Surg Radiol Anat 2014;36:789e93. 4. Hryltle J. Einige in chirurgischer Hinsicht Wichtige Gefaszvarietaten. Med J ber ost Staates 1841;24e421. 5. Quain R. The Anatomy of the Arteries of the Human Body. London: Taylor and Walton, 1844.
Typically, internal carotid artery (ICA) occlusion precludes carotid endarterectomy. Extracranial branches of the ICA are uncommon. If this anomaly occurs in the setting of total proximal ICA occlusion then revascularization is feasible. We describe a unique example of such a case.
Typically, internal carotid artery (ICA) occlusion precludes carotid endarterectomy. At the time of occlusion, thrombus extends up to the origin of the ophthalmic artery rendering the extracranial ICA unsuitable for reconstruction.1 Uncommonly, there is an extracranial branch of the ICA. If this anomaly occurs in the setting of total proximal ICA occlusion then revascularization is feasible. An example of such a case is presented here.
CASE REPORT A 64-year-old man presented with a 4-month history of multiple episodes of near syncope and repetitive amaurosis fugax of the right eye. He was a heavy smoker despite having undergone chemotherapy and radiation for squamous cell carcinoma of the larynx 9 years earlier. A carotid duplex ultrasound showed occlusion of the right common carotid artery (CCA) and ICA, but did not identify a reconstituted ICA. In addition, the left ICA had a 50e69% stenosis and there was rapid antegrade flow in the vertebral arteries bilaterally. A computerized tomography arteriogram 1
Johns Hopkins School of Medicine, Baltimore, MD.
2
Department of General Surgery, Johns Hopkins Hospital, Baltimore, MD. Correspondence to: Thomas Reifsnyder, MD, Department of General Surgery, Johns Hopkins Hospital, 4940 Eastern Avenue, Building 5A-Center, Baltimore, MD 21224, USA; E-mail: [email protected] Ann Vasc Surg 2015; 29: 362.e1e362.e2 http://dx.doi.org/10.1016/j.avsg.2014.08.019 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: July 8, 2014; manuscript accepted: August 21, 2014; published online: November 13, 2014.
confirmed occlusion of the right CCA and proximal ICA, but revealed reconstitution of the distal cervical ICA at approximately the level of the C2 vertebra (Fig. 1). At this level, a small anomalous branch of the ICA was seen. Finally, the circle of Willis appeared patent. Because the patient was symptomatic, reconstruction via a subclavian carotid bypass was planned. Exposure of the carotid was through a standard incision anterior to the sternocleidomastoid muscle. The subclavian artery was exposed via a separate supraclavicular incision. The anomalous branch of the ICA was identified (Fig. 2) about 1.5 cm distal to the carotid bifurcation. A bypass was then performed using a nonreversed greater saphenous vein graft with the distal anastomosis performed in an end-to-end fashion to the ICA. Unfortunately, while preparing the ICA to perform the anastomosis, the anomalous branch was damaged and had to be ligated. The patient recovered uneventfully and was discharged the following day. Four months after surgery the patient remained asymptomatic.
DISCUSSION Anomalous branches of the ICA are relatively rare.2,3 They were first described in the mid 19th century by Hryltle and Quain.1,4,5 Quain specifically mentions an occipital branch of the ICA.5 A recent study by Small et al. demonstrated a 0.49% prevalence of an anomalous occipital artery and a 6.25% prevalence of a superior pharyngeal artery from the ICA, both rates greater than previously seen in the literature.3 Although rare, anomalous branches of the ICA have significant implications in the surgical treatment of atherosclerotic carotid artery disease because of the natural progression of 362.e1
362.e2 Case reports
Annals of Vascular Surgery
Fig. 1. (A) Computerized tomography arteriogram (CTA): arrows to occluded right CCA and proximal ICA. Arrow to reconstituted distal right ICA. (B) CTA: Arrows to reconstituted distal right ICA and anomalous branch generating the seen collateral flow.
occlusion to the next branch of the ICA. If an anomalous branch exists, retrograde flow either from this branch to the ICA or vice versa may maintain patency of the distal ICA. When this situation exists, then surgical intervention is still possible via a carotid endarterectomy or as in this case with a concomitant CCA occlusion, a subclavian-carotid artery bypass.1 Although this is not the first report of an anomalous branch maintaining distal patency of a proximally occluded ICA, it is the first such case that included an occluded CCA necessitating the use of a subclavian to carotid bypass to restore ICA flow. This case highlights a couple of important aspects in the treatment of carotid artery disease: the need to confirm occlusion of the ICA when seen by duplex scan and to carefully define the anatomy of each patient when deciding on the most appropriate operative approach. REFERENCES
Fig. 2. Intraoperative photography of right ICA approximately 1.5 cm distal to the carotid bifurcation (white vessel loop) and reconstituting anomalous branch presumed to be the occipital artery (blue vessel loop).
1. Bowen JC, Garcia M, Garrard CL, et al. Anomalous branch of the internal carotid artery maintains patency distal to a complete occlusion diagnosed by duplex scan. J Vasc Surg 1997;26:164e7. 2. Cortes-Franco S, Mu~ noz AL, Franco TC, et al. Anomalous ascending pharyngeal artery arising from the internal carotid artery: report of three cases. Ann Vasc Surg 2013;27:240. 3. Small JE, Harrington J, Watkins E. Prevalence of arterial branches arising from the extracranial internal carotid artery on CT angiography. Surg Radiol Anat 2014;36:789e93. 4. Hryltle J. Einige in chirurgischer Hinsicht Wichtige Gefaszvarietaten. Med J ber ost Staates 1841;24e421. 5. Quain R. The Anatomy of the Arteries of the Human Body. London: Taylor and Walton, 1844.
