**1. Introduction**

Coronary artery bypass graft surgery (CABG) is one of the most commonly performed major surgeries in the United States with over 397,000 CABG's performed in 2010.(Go, Mozaffarian et al. 2012) One of the most dreadful adverse sequelae of CABG is stroke which is also the 2nd most common major post-operative complication seen with CABG, occurring in 1 to 5% of patients.(Furlan, Sila et al. 1992; Brown, Kugelmass et al. 2008) Patients suffering from postoperative stroke have a very high incidence of in-hospital mortality.(Hogue, Murphy et al. 1999) Studies have shown that presence of extracranial carotid artery stenosis (ECAS) is a strong risk factor for post-operative morbidity and mortality due post-CABG strokes.(Brown, Kugelmass et al. 2008) In this book chapter, we will review the epidemiology of concomitant coronary and carotid artery disease, the association with post-operative stroke, recommenda‐ tions for pre-operative ECAS screening and management options for patients in whom ECAS is identified.

Co-prevalence of carotid and coronary artery disease and its implications on perioperative and postoperative morbidity and mortality: Atherosclerosis is a systemic disease which is usually present in multiple vascular beds simultaneously.(Beique, Ali et al. 2006) In a recent study from the Cleveland Clinic involving 45,432 patient's, presence of carotid artery disease was confirmed as a significant risk factor for perioperative stroke after CABG. (Tarakji, Sabik et al. 2011) In the REACH Registry which was comprised of 67,888 patients, 10% of patients had concomitant coronary artery disease (CAD) and cerebrovascular disease (CVD). Anastasiasdis et al evaluated carotid arteries in 307 patients undergoing CABG and reported that while 3 out of 4 patients undergoing CABG had carotid atherosclerosis, the majority of these (63%) had <

© 2013 Sharma and Aronow; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

50% ECAS. (Anastasiadis, Karamitsos et al. 2009). Various studies have reported the incidence of ECAS with varies degree of stenosis among the patient populations undergoing CABG which are summarized in table 1.

**2. Screening for carotid artery disease**

Alexandrov et al. 2007)

**ultrasound**

Screening for carotid artery disease is usually performed with carotid duplex ultrasound. Screening recommendations for carotid artery disease are somewhat controversial and vary across medical societies.(Goldstein, Adams et al. 2006; Bates, Babb et al. 2007; Qureshi, Alexandrov et al. 2007; 2008; Brott, Halperin et al. 2011) The most widely accepted multisocietal vascular practice guidelines involving 14 different vascular societies including the American College of Cardiology Foundation, American Heart Association Task Force on Practice Guidelines, 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 recommend screening for patients with carotid bruit or patients with CAD or symptomatic PAD or atherosclerotic aortic aneurysm as well those who may not have evidence of atherosclerosis but have 2 or more cardiovascular risk factors such as hypertension, dyslipidemia, tobacco smoking, family history of premature atherosclerosis or family history of ischemic stroke.(Brott, Halperin et al. 2011). The US Preventive Service Task Force recommended against screening as it was not cost-effective in asymptomatic patients.(Bates, Babb et al. 2007) The American Society of Neuroimaging recommended against the screening of unselected populations but advised the screening of adults older than 65 years of age who have 3 or more cardiovascular risk factors (Qureshi,

Management of Carotid Artery Disease in the Setting of Coronary Artery Disease ...

http://dx.doi.org/10.5772/55669

389

For patients undergoing elective CABG, the multi-societal guidelines recommend screening for carotid artery disease in patients older than 65 years of age and in those with left main stenosis, PAD, history of cigarette smoking, history of stroke or TIA or carotid bruit. The American Heart Association and American College of Cardiology CABG guidelines offer recommendations consistent with the multi-societal vascular guidelines, however they also recommend that patients who have history of hypertension or diabetes mellitus also undergo

**3. Utility of advanced imaging carotid artery beyond carotid duplex**

Duplex ultrasound is an excellent tool to diagnose ECAS.(Eagle, Guyton et al. 1999) However there are certain inherent errors that can occur with duplex. The presence of calcification at the site of stenosis may cause underestimation of degree of stenosis; similarly contralateral occlusion may lead to falsely elevated velocities in the ipsilateral carotid artery leading to overestimation of the degree of stenosis. (Mitchell E 2004) In such situations additional imaging with computed tomography angiography (CTA) or magnetic resonance angiography (MRA) may further characterize the degree of stenosis as well as provide insight on plaque charac‐

preoperative carotid duplex scanning.(Hillis, Smith et al. 2011)


Abbreviations: CABG, coronary artery bypass grating'; ECAS, extracranial carotid artery stenosis.

**Table 1.** Prevalence of extracranial carotid artery stenosis among patients undergoing coronary artery bypass grafting.

Salasidis et al identified increasing age, history of previous carotid revascularization and presence of PAD in addition to severe ECAS as risk factors for neurological events after cardiac surgery, highlighting that ECAS is only 1 of a number of factors that drives peri-operative stroke risk.(Salasidis, Latter et al. 1995)

Interestingly, the likelihood of having ECAS increases with the underlying severity of CAD (Table 2).


**Table 2.** Prevalence of significant carotid artery stenosis (extracranial carotid artery stenosis ≥ 50%) among patients with different severity of coronary artery disease based on number of vessels involved or left main disease.

It was postulated that increasing degree of stenosis was associated with increased risk of perioperative stroke by Naylor et al who reported that among 5,453 patients undergoing CABG, the risk of perioperative stroke was <2%, 3%, 5% and 7-11% among patients who had < 50% ECAS, 50-99% unilateral ECAS, 50-99% bilateral ECAS and occluded carotid artery respectively.(Naylor, Mehta et al. 2002)
