Asian Cardiovasc Thorac Ann 2007;15:164-166
© 2007 Asia Publishing EXchange Ltd
Distal Carotid Perfusion in Combined Carotid Endarterectomy and OP-CABG
Parachuri V Rao, FRCS,
Praveen K Hosabettu, MCh,
Sanjay Dhaded, MCh,
Avery Mathew, MCh,
Julius Punnen, MCh,
Muralidhar Kanchi, MD1
Department of Cardiac Surgery
1 Department of Cardiac Anesthesia, Narayana Hrudayalaya Institute of Medical Sciences, Bangalore, India
For reprint information contact: Muralidhar Kanchi, MD Tel: 91 80 2783 5000 Fax: 91 80 2783 5222 Email: kanchi_rules_300a{at}lycos.com, Narayana Hrudayalaya Institute of Medical Sciences, #258/a Bommasandra Industrial Area, Anekal Taluk, Bangalore 560 099, India.
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ABSTRACT
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An alternative method of maintaining carotid perfusion during combined carotid endarterectomy and off-pump coronary artery bypass grafting involves insertion of a cannula in the ascending aorta after a median sternotomy. This cannula is connected to a perfusion cannula, the distal end of which is inserted into the carotid artery beyond the carotid arteriotomy. This technique of aortico-carotid shunting and carotid perfusion was utilized in nine patients who underwent successful combined carotid endarterectomy and off-pump coronary artery bypass grafting.
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INTRODUCTION
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Carotid artery disease is an important risk factor for stroke (cerebrovascular accident) after coronary artery bypass grafting (CABG).1 Hemodynamically significant carotid artery stenosis is associated with as much as 30% of strokes occurring after CABG.2 Prophylactic carotid endarterectomy (CEA) has been shown to be superior to conservative therapy for preventing stroke in symptomatic or asymptomatic patients with high-grade stenosis in patients with coronary artery disease (CAD).3 Coronary artery bypass grafting (CABG) is conventionally performed utilizing cardiopulmonary bypass (CPB), aortic cross clamping, and cardioplegic cardiac arrest. However, CABG without CPB i.e., off-pump CABG (OP-CABG) is now practiced widely and is an accepted technique of myocardial revascularization. Off-pump CABG eliminates the systemic inflammatory response syndrome (SIRS) associated with CPB and is shown to be associated with significantly less myocardial damage as compared to CABG with CPB.4 A combined CEA and CABG performed as a one-stage procedure offers better overall outcome than a two-stage approach.5 Traditionally, cerebral perfusion during CEA is maintained by the use of shunts inserted into the proximal and distal carotid arteries. We describe a technique that uses an aortico-carotid shunt to maintain distal carotid artery perfusion during a combined CEA and OP-CABG.
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TECHNIQUE
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An aortico-carotid shunt was established as follows: after sternotomy and systemic heparinization, a cannula (24-F antero-grade cardioplegia cannula, Chase Medical, Richardson, TX, USA) was placed in the ascending aorta and its distal end was connected to a perfusion cannula (PC) (coronary osteal perfusion cannula, Medtronic, DLP, Minneapolis, MN, USA). The other end of the PC was placed in the distal internal carotid artery (ICA) and was snugged (Figures 1
and 2). Carotid endarterectomy was performed under the control of vascular clamps and the distal ICA was perfused during the time of CEA and repair. Off-pump CABG was then performed using the octopus II stabilizing device.
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Figure 1. Schematic representation of modified carotid artery perfusion during combined CABG and CEA. LCCA= left common carotid artery, PA = pulmonary artery, PTFE = polytetrafluoroethylene.
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Figure 2. Operating photograph of aortico-carotid shunt: a 24-F cannula (marked 1) inserted in the ascending aorta; distal end of this cannula is connected to a perfusion cannula (marked 2), the tip of which is inserted into the distal internal carotid artery to perfuse the ipsilateral cerebral hemisphere.
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DISCUSSION
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Patients with co-existent carotid and coronary disease are at increased risk of adverse cerebral outcomes after CABG and hence represent a particularly challenging group of patients. Surgical methods aimed at reducing such risks are therefore desirable, and continue to be a topic of significant debate. Currently, surgical treatments of such concomitant disease are not uniform. Recently published randomized trials of patients with symptomatic carotid artery disease of moderate to high-grade stenosis demonstrated that carotid endarterectomy would decrease the risk of cerebrovascular accidents as compared with the non-operated groups.6 In patients with documented carotid stenosis greater than 80%, the incidence of stroke during CABG increases substantially (15% to 20%) and may be a strong argument for carotid endarterectomy to precede coronary revascularization.7
We have developed a technique of cerebral perfusion suitable for patients undergoing CEA and CABG simultaneously. The technique involves placing a shunt between the ascending aorta and the distal carotid artery. In our series, the incidence of stroke, and the mortality rate in patients selected for combined CEA and CABG was zero. While the total number of patients who underwent CEA + OP-CABG was small, our series reported here is unique in the sense that CEA was performed concurrent with an off-pump technique of CABG. Modified cerebral perfusion using an aortico-carotid shunt was achieved which is technically simple and reproducible. The advantage of this technique is three fold. Firstly: the proximal carotid artery is not cannulated thereby improving surgical access, secondly: it avoids disruption of any atherosclerotic plaques from the proximal carotid artery, and thirdly: the aortic pressure to a large extent is directly transmitted to the distal internal carotid artery to perfuse the cerebral hemisphere. However, this technique is not suitable for patients with diseased or atherosclerotic aorta and those undergoing isolated carotid endarterectomy.
An aortico-carotid shunt using our technique allows improved predictability of flow compared with traditional shunts, thus obviating concern about common carotid or innominate artery lesions. Additionally, the proximal lumen of the traditional shunt may abut against the vessel wall compromising the flow or resulting in a variable flow rate. This is eliminated in the technique described as the flow from the aorta is unlikely to be altered, and the aortic end of the cannula is visible at all times.
Some form of patch closure of the carotid artery after endarterectomy is an accepted technique (vein patch etc.) to prevent luminal narrowing. We use the polytetrafluoroethylene (PTFE) patch, as the vein patch has been shown to be associated with complications such as aneurysm and atheroma formation.
Presented at the Annual Conference of the European Association of Cardiothoracic Anaesthesiologists, London, 9th–11th July, 2004.
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ACKNOWLEDGMENTS
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The authors gratefully acknowledge the contributions of Dr. Ravindra Setty, Dr. Sanjay Kumar Banakal, Dr. Sreekar Balasundaram, and Dr. DP Shetty for assistance during surgery and preparation of the manuscript, and Mr. S Mahadevan for secretarial assistance.
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REFERENCES
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- Faggioli GL, Curl GR, Ricotta JJ. The role of carotid screening before coronary artery bypass. J Vasc Surg 1990;12:724–31.[Medline]
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- Endarterectomy for asymptomatic carotid artery stenosis. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. JAMA 1995;273:1421–8.[Abstract/Free Full Text]
- Braun SL, Barankay A, Mazzitelli D. Plasma troponin T and troponin I after minimally invasive coronary bypass surgery. Clin Chem 2000;46:279–81.[Free Full Text]
- Brodkin IA, Murkin JM. Protection of the brain during cardiac surgery. In: Hensley FA, Martin DE, editors. A Practical Approach to Cardiac Anesthesia. 2nd ed. Boston: Little, Brown and Company, 1995;581–600.
- North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991;325:445–53.[Abstract]
- Gott JP, Thourani VH, Wright CE, Brown WM 3rd, Adams AB, Skardasis GM, et al. Risk neutralization in cardiac operations: detection and treatment of associated carotid disease. Ann Thorac Surg 1999;68:850–7.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
