Adnan Al Ayoubi, MD PhD, and Sharon Beth Larson, DO
Adapted from 1st edition chapter written by Gabriel Loor, MD, and Douglas R. Johnston, MD
Concept
- Identification of patients with carotid disease undergoing CABG
- Justify the sequence of interventions
- Perioperative strategies for stroke reduction
Chief complaint
“A 70-year-old man presents with a 2-month h/o chest pain to his local cardiologist. He recommends a stress test which is positive for myocardial ischemia. Cardiac catheterization shows the following lesions: 70% mid RCA, 80% mid circumflex and 60% proximal LAD. The patient had a transient ischemic attack (TIA) 1 month ago with no residual deficits. How would you proceed with evaluation and treatment?”
Differential
The patient has diagnosed coronary artery disease. The neurologic disease may be accounted for by embolic disease from arrhythmias or atherosclerotic disease in small or large vessels.
History and physical
The history for any patient undergoing open heart surgery should include a search for risk factors of carotid disease including prior strokes, peripheral vascular disease, coronary artery disease, age, prior carotid endarterectomy (CEA), smoking, diabetes, hypertension and family history. The physical exam should assess for any gross neurologic deficits, carotid bruits, arrhythmias or cardiac murmurs.
Tests
The patient in this scenario has risk factors for carotid disease (age, CAD and prior TIA) and should undergo a carotid duplex as well as a computed tomography (CT) scan of the head to evaluate for and characterize any new or old strokes. The ACCF/AHA issued in 2011 a class IIa recommendation for carotid artery duplex scanning in patients with high risk of concurrent carotid stenosis (age > 65, left main disease, PAD, history of stroke or TIA, hypertension, smoking or DM). An MRA or angiography may be considered for equivocal carotid lesions. It is important to document a complete preop neurologic exam in the event there are deficits postoperatively. The 2011 european peripheral artery disease guidelines recommend carotid duplex in patients > 70 years old, or younger patients with history CVA, carotid bruit, multivessel CAD or PAD (class I, level of evidence C).
Index scenario (additional information)
“He has a history of hypertension and non-insulin dependent diabetes mellitus. He has a right carotid bruit and a duplex shows 70% right ICA stenosis. CT of the head showed no evidence of a prior stroke.”
Treatment/management
Based on most recent guidelines, carotid revascularization is reasonable in CAD patients with neurologic symptoms secondary to substantial carotid stenosis (> 80%; class IIa recommendation, level of evidence C). In asymptomatic patients with severe carotid stenosis, carotid revascularization (regardless of chronology of repair) is safe and efficacious (class IIb recommendation, level of evidence C). These guidelines are based on large body of retrospective studies and expert consensus. Most experts agree that carotid revascularization is indicated if the lesion is symptomatic, bilateral, or both. There is no consensus regarding the effectiveness or staging of prophylactic carotid revascularization in patients planned to undergo CABG.
The options for this man with symptomatic carotid disease (prior TIA) and multivessel symptomatic coronary disease include staged repair (CEA and then CABG) or reversed-staged repair (CABG then CEA) or a synchronous approach under one anesthetic. Meta-analysis has shown that the mortality and stroke rate are higher with a synchronous approach (death – 5% versus 3%; stroke – 6% versus 3%) and therefore should be avoided when possible. The risk of a myocardial infarction (MI) is higher with CEA followed by a CABG and the risk of stroke is higher for CABG followed by CEA. In general, the most symptomatic territories should be addressed first and in combination if both are equally severe. This patient has symptomatic carotid disease and symptomatic coronary disease thus he is at high risk of an MI with a CEA and a stroke with a CABG. The most prudent option would be a synchronous procedure.
If the carotid disease was symptomatic and his coronary disease was not as burdensome (no recent symptoms, chronic stable plaques, mostly < 70%) then it would be reasonable to proceed with the CEA followed in 4-6 weeks by CABG. MI is more common in this situation. If the carotid lesion was asymptomatic with no prior TIA or stroke then he should undergo a CABG followed by a CEA in 4-6 weeks. A severe carotid lesion (> 60% by angio or > 80% by duplex) that is asymptomatic is still grounds for a CEA either first or in combination depending on the severity and symptomatology of the coronary disease. The same goes for a 60-80% stenosis and contralateral occlusion.
Operative steps
- Supine position, arterial line, ETT, swan, cerebral oximetry for neuromonitoring.
- Alternative options for neuromonitoring include EEG, SSEP/MEP (somatosensory evoked potentials/motor evoked potentials), and transcranial Doppler.
- Prep and drape for both a CEA and CABG.
- Begin with the CEA while the leg vein is being harvested.
- Decide ahead of time what conduits to use, if any, and determine if an adequate length of vein is available for both the bypass and CEA. Vein patches may have increased tendency for aneurysmal dilation, many surgeons prefer using a prosthetic such as bovine or hemashield patch. Choice of patch is surgeon dependent. If eversion CEA is elected, no patch is required for closure.
- Oblique incision along the anterior border of the sternocleidomastoid muscle (SCM). Divide the facial vein.
- Dissect down to the carotid artery and expose the common, internal and external carotid. Take care not to injure the vagus during this dissection.
- Get proximal and distal control (external and internal) with vessel loops.
- Give 5000 – 10,000 units of heparin, clamp. Consider a shunt if the cerebral oximetry drops excessively or EEG changes. Open the artery from the proximal common carotid up to the internal carotid beyond the area of gross intimal disease.
- Dissect the plaque with a blunt dissector. Close with vein, bovine or hemashield patch if unable to close primary defect.
- Flush all vessels beginning with the external then the internal and finally the common carotid.
- Obtain hemostasis and pack the wound.
- Complete the vein harvest, median sternotomy, and mammary takedown. Carefully palpate the aorta given the risk for ascending calcification which may require axillary cannulation. Consider utilizing epiaortic ultrasound to place aortic cannula.
- General measures to reduce stroke risk would include keeping MAPs greater than 70 mmHg during bypass, avoiding excessive manipulation of the aorta and limiting cross clamp time and frequency (single clamp vs. double). Consider off-pump CABG based on surgeon experience. After heparin has been reversed, ensure hemostasis in the neck and close over a drain.
Potential questions/alternative scenarios
“Postoperatively the patient has evidence of left sided upper extremity weakness.”
A neuro exam should be performed as soon as possible following the combined approach. Any abnormalities warrant a head CT, neuro consultation and carotid duplex. Maintain a low threshold for returning to the operating room to explore the patch if there is any hint that the neurologic impairment is due to a structural issue with the patch.
“Postoperatively the patient develops a large neck hematoma with tracheal deviation.”
If a neck hematoma develops and compromises the airway it should be opened immediately at the bedside or in the operating room if time permits. Always protect the airway with an endotracheal tube if the patient has already been extubated. After draining the hematoma, ensure hemostasis, irrigate and close over a drain.
Pearls/pitfalls
- Symptomatic coronary artery disease (worsening angina, NSTEMI, STEMI) requires coronary intervention urgently. If the patient has symptomatic carotid disease with at least moderate grade carotid stenosis (50% by duplex) then perform a CEA in the same setting. Carotid artery stenting in the same hospitalization/day may be performed prior to CABG. There are currently very limited data on the efficacy of this method.
- CEA should also be considered in the same setting if a patient who needs an urgent CABG has an asymptomatic carotid lesion > 60% by angio or > 80% by duplex. Same goes for a patient with 60-80% stenosis but contralateral occlusion.
- CEA can be safely delayed in patients undergoing CABG with mild or moderate grade lesions (< 80% duplex) who have not had a prior stroke or TIA.
- If the carotid disease is symptomatic and his coronary disease is not as burdensome (no recent symptoms, chronic stable plaques, mostly < 70%) then it would be reasonable to proceed with the CEA followed in 4-6 weeks by CABG.
Suggested readings
- Brott TG, Halperin JK, Abbara, S et al: 2011 SA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. Circulation 124:e54-e130, 2011.
- Naylor AR, Bown MJ. Stroke after cardiac surgery and its association with asymptomatic carotid disease: an updated systematic review and meta-analysis. Eur J Vasc Endovasc Surg 41:607-624, 2011
- Burger MA et al. Coronary bypass and carotid endarterectomy: does a combined approach increase risk of stroke? A meta-analysis. Ann Thor Surg 1999;68;14-20.
- Ouzounian M, LeMaire SA, Coselli JS. Chapter 73 Occlusive disease of the brachiocephalic vessels and management of simultaneous surgical carotid and coronary disease. Selke FW, del Nido PJ, Swanson SJ (eds). Sabiston & Spencer Surgery of the Chest 2016
- Kwon MH, Tolis Jr G, Sundt TM. Chapter 20 Myocardial revascularization with cardiopulmonary bypass. Cohn LH and Adams DH (eds). Cardiac Surgery in the Adult 2018
