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Calcium score of coronary artery stratifies the risk of obstructive coronary artery diseases.

BACKGROUND AND AIMS
Coronary heart disease is a major health problem in Malaysia with high morbidity and mortality. Common primary screening tool of cardiovascular risk stratification is exercise treadmill test (ETT). This communication is to determine the performance of coronary artery calcium score a new method to stratify the presence of obstructive coronary artery disease (CAD) in comparison to traditional ETT in patients having coronary artery diseases.


MATERIALS AND METHODS
Patients between 30 to 60 years old attended the ETT to screen for ischemic heart disease were recruited for Agatston coronary artery calcium score (CACS) of multi-sliced computed tomography (MSCT). Subsequently all patients underwent a full MSCT coronary angiography. The major determinant was the state of CAD whether obstructive (50% stenosis or more) or non-obstructive (less than 50% stenosis). All patients diagnosed with obstructive CAD on MSCT coronary angiogram were subjected to invasive coronary angiogram (ICA) to confirm the findings and planned the need for revascularization.


RESULTS
The CACS was 100% sensitivity and 97.5% specificity in detecting obstructive CAD at the optimal cut-off value of 106.5 and above. The positive predictive value (PPV) at CACS ≥ 106 was 71.4% and the negative predictive value (NPV) was consistent at 100%. Compare to ETT, the CACS discriminative value and diagnostic performance was much better (PPV 71.4% vs. 45.5%), respectively.


CONCLUSION
CACS can be a good diagnostic screening tool in patients suspected of CAD, and particularly within the non-diagnostic ETT subgroup with low to moderate cardiovascular risks.