RESEARCH ARTICLE SA JOURNAL OF DIABETES & VASCULAR DISEASE 8 VOLUME 21 NUMBER 1 • November 2024 controls and that the prevalence of increased CIMT was very high (82.8%) in the Nigerian population.31 In our study, 34% of patients with diabetes had abnormal CIMTs, significantly more than patients with normal CIMTs. Hypertension is multifactorial in cause, including but not limited to, high sodium intake, cigarette smoking, unhealthy diet, low potassium intake, lack of physical activity32 and family history of hypertension.33 Evidence suggests that hypertension is strongly associated with increased CIMT thickening.34 The carotid artery has a relatively small media compared with muscular arteries. Therefore an increased CIMT is thought to primarily represent intimal rather than medial thickening, supporting atherosclerosisrelated cardiovascular events rather than hypertrophy of the medial layer of the carotid artery.35 Our results (Table 2) showed an association between hypertension and an increased CIMT, with significantly more patients presenting with hypertension in the abnormal CIMT group (85.25%) compared to the normal CIMT group (57.14%). Similar observations were reported by Rashid and Mahmud, Magnussen, and Chen et al.28,35,36 The MONICA Risk, Genetics, Archiving, and Monograph (MORGAM) biomarker project demonstrated that adding NT-proBNP to a conventional risk model can improve a 10-year risk estimation for cardiovascular events.37 This study showed that NT-proBNP was significantly higher pre-operatively in patients with an abnormal CIMT. A response to left ventricular strain or ischaemia causes a release of NT-proBNP, which has been found to be an important biomarker for left ventricular systolic dysfunction and left ventricular stress in the general population.38 There was no correlation between CIMT and intra-operative factors, even when a higher abnormal CIMT cut-off value was used. A possible reason is that the study population was too small and that subtle differences may not have been detected. Interestingly, no difference in lactate values was found between the groups. Insufficient oxygen delivery and hypoperfusion during CPB contribute to hyperlactataemia.39 CIMT is a marker of subclinical atherosclerosis and endothelial dysfunction,40 which is a factor that would increase lactate production intraoperatively due to the systemic inflammatory response caused by CPB.41 An increase in lactate is associated with poor outcomes and increased mortality rates in cardiac surgery patients.42 The post-operative complications were comparable between the groups with no statistically significant differences. Our study’s overall post-operative complication rate was low but corresponds with the overall rate of complications reported after CABG surgery (1–3%).43 Data on the accepted normative values are unavailable because there is no widely accepted cut-off value for what constitutes an adverse/abnormal CIMT value. Many variables affect the thickening of the carotid intima in different populations, whether it be age, ethnicity or diet.35 Even when using a higher abnormal CIMT cut-off value of 0.09 cm, there was no relationship between higher CIMT values and increased post-operative outcomes and complications. Our results agree with Aboyans et al.,19 who also found little value in pre-operative CIMT. By contrast, some value was reported in off-pump CABG where increased CIMT (0.9 mm) was associated with increased 30-day morbidity rates.20 However, based on our results, CIMT should not be considered a predictor for surgical outcomes in ACS patients undergoing CABG surgery using CPB. Before criteria for abnormal CIMT can be set, there is a need for measurement consensus and population reference values. There are currently no set CIMT population values for South Africa. This study is limited by its retrospective design and the sample size was small. For this reason, only assumptions can be made. A larger patient population may reveal more definite answers on whether increased CIMT values can predict surgical outcomes. Conclusion Our study demonstrated an association between abnormal CIMT and pre-operative risk factors such as BMI, diabetes, hypertension and NT-proBNP level. However, there was no correlation between abnormal CIMT and an increased rate of adverse intra- and postoperative patient outcomes. Therefore, our study does not support the use of CIMT to predict adverse events in patients undergoing CABG surgery. Further studies that include larger patient numbers are needed to confirm our observations. Acknowledgement The authors thank the Robert WM Frater Cardiovascular Centre for their contribution towards this research study. References 1. Mc Namara K, Alzubaidi H, Jackson JK. Cardiovascular disease as a leading cause of death: how are pharmacists getting involved? Integr Pharm Res Pract 2019; 8: 1–11. 2. Yuyun MF, Sliwa K, Kengne AP, Mocumbi AO, Bukhman G. Cardiovascular diseases in sub-Saharan Africa compared to high-income countries: an epidemiological perspective. Glob Heart 2020; 15(1): 15. 3. Abdelatif N, Peer N, Manda SO. National prevalence of coronary heart disease andstroke in South Africa from 1990–2017: a systematicreview and metaanalysis. Cardiovasc J Afr 2021; 32(3): 46–50. 4. Geroulakos G, O’Gorman DJ, Kalodiki E, Sheridan DJ, Nicolaides AN. The carotid intima–media thickness as a marker of the presence of severe symptomatic coronary artery disease. Eur Heart J 1994; 15(6): 781–785. 5. Kitagawa K, Hougaku H, Yamagami H, et al. Carotid intima–media thickness and risk of cardiovascular events in high-risk patients. Results of the Osaka Follow-Up Study for Carotid Atherosclerosis 2 (OSACA2 Study). Cerebrovasc Dis 2007; 24(1): 35–42. 6. Kablak-Ziembicka A, Tracz W, Przewlocki T, Pieniazek P, Sokolowski A, Konieczynska M. Association of increased carotid intima–media thickness with the extent of coronary artery disease. Heart 2004; 90(11): 1286–1290. 7. Bots ML, Evans GW, Tegeler CH, Meijer R. Carotid intima–media thickness measurements. Chin Med J 2016; 129(2): 215–226. 8. Saxena Y, Saxena V, Mittal M, Srivastava M, Raghuvanshi S. Age-wise association of carotid intima media thickness in ischemic stroke. Ann Neurosci 2017; 24(1): 5–11. 9. Greenland P, Alpert JS, Beller GA, et al. 2010 ACCF/AHA guideline for assessment of cardiovascular risk in asymptomatic adults. J Am Coll Cardiol 2010; 56(25): 50–103. 10. Chambless LE, Heiss G, Folsom AR, et al. Association of coronary heart disease incidence with carotid arterial wall thickness and major risk factors: the Atherosclerosis Risk in Communities (ARIC) study, 1987–1993. Am J Epidemiol 1997; 146(6): 483–494. 11. van der Meer IM, Bots ML, Hofman A, Iglesias del Sol A, van der Kuip DAM, Witteman JCM. Predictive value of noninvasive measures of atherosclerosis for
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