Abstract
CT coronary calcium (CT Ca) score is a non-invasive method for assessing presence and severity of CAD in an individual. Coronary angiogram (CAG) is an invasive procedure and remains the gold standard for diagnosis of coronary artery disease (CAD). AIM: To compare the efficacy of CT Ca score with CAG, for predicting severity of CAD during pre liver transplant (LT) recipient work-up. METHODS: CT Ca score was done for all listed patients. CAG was reserved for those >50 years or a CT Ca score >400 HU (Agtston scoring system). The severity of coronary artery stenosis by CAG was graded as normal, mild (<50% stenosis), moderate (50-75% stenosis, severe (>75 % stenosis) and extensive (> one major coronary artery) was involved. STATISTICAL ANALYSIS: Weighted Cohen's Kappa was used to assess the agreement between the CT Ca score and CAG for ordinal outcome. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value and diagnostic accuracy) were calculated for CT Ca score considering CAG classification as the gold-standard. RStudio Desktop latest version was used for analysis. RESULTS: 158 patients had both CT Ca score and CAG. There was a significant overlap between CT Ca score and CAG score in detecting CAD. Comparing CT Ca score and CAG, 70 patients were correctly classified (44.3%) by the former, 66 (41.8%) were over-classified and 22 (13.9%) were under-classified. Overall, there was a statistically significant fair agreement between CT CA score and CAG severity index (Weighted Cohen's Kappa = 0.258; 95% CI: 0.140 to 0.377; P < 0.001). The accuracy with CT Ca score was higher (70.89%) for obstructive/non-obstructive CT Ca score i.e. >100 HU) compared to the abnormal/normal CT Ca scores (60.13%). For obstructive/non obstructive classification, CT Ca score was significant for past CAD (0.004). CONCLUSIONS: CT Ca score provides a convenient and non-invasive method for the initial assessment of obstructive/non obstructive CAD in liver transplant recipients.