The spectrum and distribution of imaging findings at coronary computed tomography angiogram in patients suspected to have coronary artery disease. A Cross-sectional study carried out at plaza imaging solutions in Nairobi, Kenya
Background Coronary CT angiography (CCTA) has in the recent past evolved rapidly due to development of sophisticated multi detector row CT (MDCT). The cardinal indication for CCTA is the evaluation of suspected or known coronary artery disease (CAD). Coronary CTA imaging can detect and characterize atherosclerotic plaques. In addition, it can confirm or exclude luminal stenosis. Other applications include identification and assessment of variations in coronary arterial circulation patterns, evaluation of isolated anomalous coronary vessels, by-pass grafts, coronary stents patency and assessment of left ventricular function. Study objective: This study was set to determine the spectrum, pattern and distribution of imaging findings at Coronary CT angiograms as detected by a 320 row MDCT in patients who had undergone coronary CTA. Study design: A cross sectional study. Setting: Plaza Imaging Solutions Limited, Nairobi, Kenya. Subjects: Patients imaged at Plaza Imaging Solutions Limited over a period of 6 months. Materials and methods: Study subjects: Consecutive patients referred for coronary CTA at Plaza Imaging Solutions Limited and met the inclusion criteria. Ethical considerations: Ethical approval and clearance was obtained from the KNH-UON Ethics Review Board. Written and verbal consent was obtained from the participating persons and/or their kin. Tools: A two-part data collection form was used to manually record all the relevant data. The information included socio-demographics, clinical and imaging finding of Coronary CTA. A low dose calcium scan and a standard coronary CTA were performed. Each Coronary CTA study was reviewed by a radiologist together with the researcher. Statistical analysis: Data analysis was performed using the Statistical Package for Social Sciences (SPSS) employing relevant statistical tests. The results were presented in form of frequency tables, graphs and charts and discussed accordingly. Statistical significance was set at p < 0.05 Results During the 6 month period, 38 out of a total of 42 scanned patients were recruited into the study. The age distribution ranged from 21 to 89 years with a mean age of 56 years (SD 14.819.2). Male to female ratio was 5:4 Chest pain (angina) accounted for the commonest indication for imaging at 63.2%. Risk factors of hypertension and diabetes mellitus were noted in 39.5% of patients. More males reported a co- morbid state of diabetes mellitus (DM-Type II) while more females 50% had hypertension. Overall there were more patients with abnormal scans at 76% than the normal. Atherosclerotic coronary plaque lesions were the most commonly encountered abnormality accounting for 93.1%. The predominant plaque type was the non-calcified plaque seen in 50% of males and 61.5% of females. The total calcium scores (Agatston) ranged from 0 to 242. Calcified plaques were predominantly on the left anterior descending coronary artery (LAD), while the non-calcified plaques were significant on the right coronary artery (RCA). Conclusion The study demonstrated the common occurrence of coronary atherosclerotic plaques in the older age group with lower incidence seen in younger individuals. It also demonstrated the wide spectrum of luminal effect caused by the atherosclerotic plaques. Furthermore it demonstrated the paucity of calcified atherosclerotic plaques amongst the local population undergoing coronary CTA highlighting the insignificant nature of coronary calcium score in this setting. Recommendations Based on the findings and conclusions of this study, a recommendation is made for coronary CTA to be performed in the older age group of > 55 years of age with symptomatic features of ischemic heart disease. Coronary calcium scoring is not necessary in individuals undergoing coronary CTA in this setting (black race) as no correlation is found between total calcium score and atherosclerotic disease burden.