Geethu Elizabeth, Punnen (2017) A Comparative study of conventional risk models and CT coronary angiography. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION : Coronary artery disease (CAD) is a pathologic process that affects the coronary arteries resulting in its narrowing or complete blockage, and is most commonly caused by atherosclerosis. Atherosclerosis is the process by which cholesterol and fatty deposits build up along the inner walls of arteries resulting in its narrowing, thereby restricting blood flow to the muscles of the heart. In both developing and developed countries, coronary artery disease is one of the leading causes of mortality and morbidity. Although deaths due to coronary heart disease (CHD) have reduced over the past few decades, it is still the leading cause of death, accounting for 17.3 million deaths per year. By 2030, this number is expected to increase to more than 23.6 million. 80 % of global deaths due to CHD occurs in low and middle income countries. AIM: To study the degree of correlation between conventional risk models and coronary atherosclerotic disease burden s well as risk prediction as estimated on coronary CT angiography in a tertiary care hospital in South India. Primary objectives: 1. To determine the NCEP Core risk category among patients referred for a coronary CT angiography. 2. To assess the calcium score (CACS), segment plaque score (SPS), segment involvement score (SIS), segment stenosis score (SSS) and Modified dukes prognostic score, based on coronary CT angiography in the same group of patients. 3. To describe plaque characteristics as lipid rich, fibrous, fibrocalcific and calcified plaques. 4. To correlate the risk prediction of Modified Duke’s score with the NCEP core risk score. Secondary objectives ( long term): To describe the change in medical management, in the referred patients, post coronary CT angiography. Design of data collection: Prospective descriptive study Cases: Patients with suspected/diagnosed coronary artery disease, which are advised to undergo coronary CT angiography in the period between Jan 2015 and April 2016. Sample size : 144 cases. MATERIALS AND METHODOLOGY: Study period: The study was conducted in the Department of Radiology in the period between Jan 2015 and May 2016 after obtaining approval from the Institutional Review Board (IRB Min No 9197 (OBSERVE) DATED 8.12. 2014). Study design: Prospective cross sectional descriptive study. Inclusion criteria: Consecutive patients with suspected coronary artery disease, who were advised to undergo coronary CT angiography in the period between Jan 2015 and May 2016 and gave informed consent for the same, were included. Informed consent was taken by the principal investigator after ensuring that there was no contraindication for undergoing a CT coronary angiogram. Exclusion criteria: 1. Patients with contraindication to the administration of iodinated contrast. 2. Previous history of myocardial infarction, stenting, coronary artery bypass graft stenting. 3. Poor image quality resulting in suboptimal image analysis. 4. Pregnancy. 5. If lipid profile of the patient was not readily available. METHODOLOGY: All consecutive adult patients advised to undergo coronary CT angiography for suspected coronary artery disease will be recruited for the study, assuming they have no contraindication for the same. Informed consent will be obtained by the principal investigator. Demographic details of the patient with relevant history of risk factors, along with lipid profile values will be collected and the Framingham risk score will be calculated. Risk stratification of each patient according the NCEP core risk score will be performed. These parameters will be compared with findings on CT coronary angiography. The scores that will be assessed are : 1. Calcium score, 2. Segment plaque score, 3. Segment involvement score, 4. Segment stenosis score, 5. Modified Duke’s prognostic criteria, 6. Coronary plaque characteristics. Outcome measures: • Burden of coronary artery disease among the NCEP core risk groups as assessed by calcium score, segment plaque score, segment stenosis score, and segment involvement score. • The distribution of plaque characteristics among the risk groups. • The correlation of risk prediction of conventional risk models (NCEP ATP III guidelines) and Modified Duke’s prognostic index in predicting a coronary event. CONCLUSION : In conclusion, it is evident that coronary CT angiography is an accurate, reliable noninvasive imaging tool, especially in patients in low and intermediate risk groups, for the diagnosis of early, subclinical CAD. It also has additional benefits of quantifying plaque burden and detecting the presence of vulnerable low density plaques. It has been demonstrated that there is moderate correlation between Framingham risk estimates and NCEP risk categories and presence of coronary artery plaque and the coronary artery disease burden in our study population, especially among the low risk and high risk groups. But among intermediate risk patients, the correlation of conventional risk scoring systems with plaque burden and vulnerable plaque was observed to be less robust. The results of our study suggests that coronary CT angiography should be considered in the intermediate risk group to guide planning of optimal therapy and preventive strategies.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Comparative study ; conventional risk models ; CT coronary angiography. |
| Subjects: | MEDICAL > Radio Diagnosis |
| Depositing User: | Subramani R |
| Date Deposited: | 23 Dec 2017 18:16 |
| Last Modified: | 23 Dec 2017 18:16 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/4750 |
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