|Year : 2013 | Volume
| Issue : 2 | Page : 43-47
Prevalence of carotid artery disease in candidates undergoing coronary bypass graft seen at Madras Medical Mission
Abiodun M Adeoye1, Ajit S Mullassari2, SR Ramkumar2, K Latchumanadhas2
1 Department of Medicine, University College Hospital and University of Ibadan, Ibadan, Nigeria
2 Department of Adult Cardiology, Institutes of Cardiovascular Diseases, Madras Medical Mission, Chennai, India
|Date of Web Publication||19-Jul-2013|
Abiodun M Adeoye
Department of Medicine, University College Hospital and University of Ibadan, Ibadan
Source of Support: None, Conflict of Interest: None
Background: Significant carotid artery disease in candidates going for coronary artery bypass graft (CABG) increases the risk of developing peri-operative neurologic events. Therefore, a pre-operative carotid Doppler ultrasonography, which is simple, non-invasive, and cheap may be indispensable. In this study, we report the prevalence of carotid disease in candidates for CABG and assessed the correlates between carotid artery disease and coronary artery disease (CAD). Materials and Methods: Seventy three consecutive patients undergoing elective CABG were recruited over 7 months, January to July 2007. All participants underwent pre-operative carotid Doppler assessment for level of stenosis and site of carotid plaque. Using the criteria defined by the Society of Radiologists in the Ultrasound Consensus, the degree of stenosis was stratified into the categories of normal (no stenosis), 50% non-obstructive carotid disease, 50-69% significant stenosis, 70% critical stenosis to near occlusion, near occlusion, and total occlusion. Patients with previous CABG, congestive cardiac failure, and high-risk surgery were excluded. Results: The mean age of patients was 65.0 ± 7.2 years with male-female ratio of 9:1. Twenty one (28.8%) patients had normal carotid arteries 45 (61.6%) had non-obstructive carotid artery disease 4 (5.5%) had significant carotid stenosis and 3 (4.1%) had critical carotid stenosis. Carotid bulb was the most common site of plaque formation while left internal carotid artery was the commonest site of both significant and critical carotid stenosis. Patients with significant carotid artery disease had 3 times the odd of having severe CAD (left main disease/triple vessel disease). However, this was not statistically significant (OR 2.75, P = 0.284). Conclusion: The high frequency of carotid artery disease in this study underscores the need for routine ultrasonic carotid assessment in candidates for CABG to ensure early detection and prompt management of carotid disease in a candidate of CABG which may prevent untoward peri-operative neurologic events.
Keywords: Carotid artery disease, coronary artery disease, coronary bypass graft
|How to cite this article:|
Adeoye AM, Mullassari AS, Ramkumar S R, Latchumanadhas K. Prevalence of carotid artery disease in candidates undergoing coronary bypass graft seen at Madras Medical Mission. Sahel Med J 2013;16:43-7
|How to cite this URL:|
Adeoye AM, Mullassari AS, Ramkumar S R, Latchumanadhas K. Prevalence of carotid artery disease in candidates undergoing coronary bypass graft seen at Madras Medical Mission. Sahel Med J [serial online] 2013 [cited 2022 May 24];16:43-7. Available from: https://www.smjonline.org/text.asp?2013/16/2/43/115254
| Introduction|| |
Atherosclerosis, a progressive systemic inflammatory disorder is a harbinger of cardiovascular events. Despite the decline in cardiovascular death through preventive measures in United State, cardiovascular disease is the leading cause of death in that community. , The incidence is increasing and has reached epidemic proportions in some developing countries. In India, for example, during the past 30 years, coronary artery disease (CAD) rates have doubled among both rural and urban settlers. By 2015, cardiovascular diseases are projected to account for 34% of male deaths and 32% of female deaths; amounting to a total of 1.5 million deaths.  From the foregoing, it is imperative to improve attention on the disease prevention targeted at early identification of people at risk for optimal intervention.
Carotid artery diseases are common findings in patients with CAD.  Coexistence of carotid and CADs is a challenge. Despite the non-surgical approach to management of CAD, coronary artery bypass graft (CABG) remains one of the most frequent operations world-wide  and patients with concomitant CAD and carotid disease are at the risk of developing peri-operative neurological events with stroke being the most prevalent. ,,,,, Therefore, pre-operative non-invasive carotid Doppler ultrasonography is a useful screening tool for carotid artery disease in all patients undergoing CABG. This technique combines real-time B-mode imaging and a single-gated pulsed Doppler system. Compared to conventional angiography studies, Roederer et al. found that ultrasonic carotid artery duplex scanning yields a sensitivity of 99% and specificity of 84%. The prevalence of carotid artery disease in patients undergoing CABG is reported to be from 2.3% to 54% in different reports.
While the vast majority of these reports were carried out on Caucasians, there are few studies , in India population that assessed the prevalence of carotid stenosis in candidates of CABG. This study therefore reports the prevalence of carotid artery disease in candidates of CABG and assessed the correlation between carotid artery stenosis and CAD.
| Materials and Methods|| |
The study was carried out at the Adult Cardiology Department of Institute of Cardiovascular diseases, Madras Medical Mission, Chennai, India. The hospital has more than 256 beds, five operation theatres and two state-of-the-art cineless Cath Labs besides a host of other facilities. The coronary care unit is 16-bedded and fully equipped to care for all cardiovascular emergencies.
Seventy three consecutive patients undergoing elective CABG were recruited over 7 months from January to July 2007. All the subjects had detailed history and clinical assessment. Anthropometric measurements including height and weight were obtained. Height was measured without shoes to the nearest centimeter using a ruler attached to the wall while weight was measured to the nearest 0.1 kg on an electronic scale with the subject wearing light outdoor clothing and no shoes. Blood samples were taken for estimation of cholesterol. The carotid arteries were evaluated using high resolution B mode ultrasonography with 7.5 MHz linear-array transducer to evaluate the presence and site of plaques and to quantify the degree of stenosis. Examination was performed with the patient in the supine position and the head slightly tilted towards the opposite side. Using the criteria defined by the Society of Radiologists in the Ultrasound Consensus, , the degree of stenosis was classified as normal (no stenosis), 50% non-obstructive carotid disease, 50-69% significant stenosis, ≥70% critical stenosis and total occlusion. Participants with critical carotid stenosis had carotid stents done prior to surgery. Patients with previous CABG, congestive cardiac failure, and high-risk surgery were excluded from the study.
Data collected was entered into the computer and analyzed using the Statistical package for the Social Sciences, version 15 (SPSS Inc. Chicago, IL, USA). Descriptive statistics such as means and standard deviations were used to summarize quantitative variables while categorical variables were summarized using frequencies and proportions. Likely predictors of CAD were determined using the binary logistic regression. All tests were declared at the 5% level of significance.
| Results|| |
The mean age of subjects was 65.0 ± 7.2 years with male:female ratio 9:1 [Table 1]. Normal carotid arteries were seen in 21 (28.8%) patients while 45 (61.6%) had non-obstructive carotid artery disease, 4 (5.5%) had significant carotid stenosis and 3 (4.1%) had critical carotid stenosis [Figure 1]. Carotid bulb was the most common site of plaque formation while left internal carotid artery was the commonest site of both significant and critical carotid stenosis [Figure 2]. Patients with significant carotid artery disease have almost 3 times the odd of having severe coronary disease (left main disease/triple vessel disease). This was however not statistically significant (OR 2.75, P = 0.284).
|Figure 1: Proportional distribution of carotid artery plaques in study subjects (N = 73)|
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| Discussion|| |
The present study showed high frequency of carotid diseases among Indian patients undergoing elective CABG. Carotid artery disease in preclinical stage with carotid intima-media thickness (CIMT > 1 mm) and non-obstructive (<50% plaques) is associated with an increased risk of stroke, neurologic injury, in-hospital mortality, and longer hospitalization in patients undergoing cardiac surgery.  The risk of perioperative stroke in patient with normal carotid artery undergoing CABG is between 0.2% and 5.3%, but it increases to 15% in patient with critical carotid stenosis (>70% lesion). ,,
Previous studies on pre-operative carotid ultrasonography have shown the prevalence of significant carotid artery stenosis in candidates of CABG to from 2% to 18%. ,,,,,,,,, Like in the current report, Cirilo et al.  reported a prevalence rate of non-obstructive carotid diseases of 61.6% in an apparently greater study population. In contrast to our finding, they reported 10.2% critical stenosis among their subjects. The higher frequency of significant carotid stenosis in their study is similar to result from the Western Nations and may be due to the high rate of cardiovascular risk factors in this group. Cirilo et al.  documented active smoking, dyslipidemia, and diabetes in 79.1% 54%, and 28.1% of patients, respectively. 
Interestingly, Rath et al.  from the same region, in their investigation reported non-obstructive carotid disease, significant carotid disease and critical stenosis in 66.3%, 5.3% and 3.7% of patients respectively, which is similar to our findings. This underscores the need for non-selective carotid screening before cardiac surgery with a view to identify those at risk of stroke during surgery that will benefit from pre-operative carotid interventions. They also demonstrated that untreated critical carotid artery stenosis was associated with a higher stroke rate. While critical stenosis is an important risk for stroke during surgery, the presence of carotid disease irrespective of degree of stenosis heightens the risk among those undergoing cardiac surgery as demonstrated in Cirilo study,  which showed that out of 31 participants that developed stroke in the course of their study, only 8 (26%) had critical carotid stenosis while the rest had non-obstructive carotid diseases. The high prevalence of non-obstructive carotid disease in our study is worrisome, despite the uneventful course in the hospital; therefore, A prospective study is required to assess long-term post-operative outcomes.
We observed that carotid bulb was the most common site of plaque formation and critical stenosis was at the left internal carotid artery. This is similar to the work of Kallikazaros et al.  who reported bulb as the most common site followed by internal carotid artery, and the common carotid artery (CCA).
While the past research focus has been on CIMT prediction of cardiovascular events, it has been shown that carotid plaques reflect overall atherosclerosis burdens, and when compared to CIMT, it serves a better predictor of cardiovascular death and non-fatal myocardial infarction. ,,,,,,, Though several studies have correlated the presence of increase CIMT with CADs, correlational studies on the degree of carotid stenosis and severity of CADs are few. , In the current report, subjects with obstructive carotid disease have three times the odd of having severe CADs though this was not statistically significant. The lack of statistical significance may be accounted for by small study population and the short duration of the study. Prospective study in a larger study population is required to substantiate our findings.
We conclude that the high prevalence of carotid artery disease in this study underscores the need for routine ultrasonic carotid assessment in candidates of CABG. Early detection and prompt management of carotid disease irrespective of degree of stenosis may prevent untoward cerebrovascular events pre and post CABG.
| Acknowledgments|| |
We would want to thank World Heart Federation who through her Twin center training fellowship sponsored the training of corresponding author at Madras Medical Mission Chennai, India, which provided an opportunity for this study. Special thanks go to Professors O.A Ogunniyi, B. L Salako, and A. O Lasisi of University College Hospital Nigeria who read through the manuscript and made useful suggestions.
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[Figure 1], [Figure 2]