Computed tomography coronary angiography compared to conventional coronary angiography in evaluation and prediction of outcome of percutaneous intervention for coronary chronic total occlusions

Abstract

Aims: To compare between computed tomography coronary angiography (CTCA) and conventional coronary angiography (CCA) in assessment of coronary chronic total occlusions (CTOs). To better define the added value of CTCA in prediction of outcome of percutaneous coronary intervention for chronic total occlusions (CTO PCI). Methods and results: Thirty one coronary CTO lesions were studied. The median estimated CTO duration was 12 months (range 3-108). CTCA was performed in all patients using 320-channel scanner. The median estimated CTO length by CTCA was 22.2 mm (range 7.7-89.4) and by CCA was 20.9 mm (range 6.1-80.7); p= 0.49. Calcification within the CTO segment was detected by CTCA in 24 (77.4%) CTO lesions and by CCA in only 14 (45.2%) CTO lesions; p=0.019. Severe calcification; >50% of cross sectional area (CSA) was detected by CTCA in 12 (38.7%) of the CTO lesions. Proximal vessel tortuosity, shape of the stump and presence of side branch at the CTO entry were similarly detected by both modalities; p=1. Thirty four attempts at CTO PCI were performed in the 31 patients. Eighteen (52.9%) of the attempts utilized the antegrade approach, 3 (8.8%) utilized the retrograde approach alone and 13 (38.2%) of the attempts utilized a bidirectional approach. The overall success rate per attempt was 85.3%. Calcium occupying >50% of CSA by CTCA was the only predictor of failure of the antegrade approach for CTO PCI; p=0.036. There were trends of longer estimated CTO duration and longer estimated CTO length in the failed antegrade approaches for CTO PCI (p=0.073, p=0.063 respectively). None of the CTCA or the CCA factors was found to predict the outcome of the retrograde approach for CTO PCI. A trend of successful outcome of the retrograde approach for CTO PCI was noted with higher Werner collateral channel grades (p=0.057). Conclusions: CTCA provides better means of detection and assessment of calcification within the coronary CTO lesions than CCA. Severe calcification (>50% of CSA by CTCA) was the only statistically significant predictor of failure of the antegrade approach for CTO PCI.