Feasibility of Calculating SYNTAX Score Using Coronary Computed Tomography with Reference to Invasive Coronary Angiography

Abstract

Complexity of coronary artery disease and coronary lesion characteristics are well recognized predictors of periprocedural complications and long-term mortality. The SYNTAX score was developed to comprehensively assess lesion characteristics and better anticipate the risks of percutaneous or surgical revascularization and hence guide the team of managing physicians ‘Heart team’ to the optimal method of revascularization. We tested the feasibility of calculating SYNTAX score using Multislice Computed tomography Coronary Angiography (MSCTCA) in comparison to using invasive coronary angiography as a means of noninvasive assessment which can facilitate upstream communication between the heart team and pre plan ad hoc PCI versus CABG if results of the ICA were confirmatory to the CT. Our study was conducted on 40 patients presenting to the Cardiology department at Ain shams university hospitals and Dar AL Fouad hospital between July 2014 and September 2015 who initially underwent MSCT CA for the assessment of CAD. Regarding the conventional vessel based analysis, the number of vessels affected by MSCT CA was 1.78 ± 0.73 and by ICA was 1.75 ± 0.70 (Kappa = 0.88) indicating an almost perfect measure of agreement between both modalities. The number of lesions identified by MSCT CA was 2.15 ± 1.09 and by ICA was 2.07 ± 1.02 (kappa = 0.69) indicating a substantial measure of agreement. The number of segments involved by MSCT CA was 2.50 ± 1.45 and by ICA was 1.75 ± 0.70 (kappa = 0.67) indicating also a substantial measure of agreement between both techniques. The mean total SYNTAX score by CT was 16.08 ± 8.53 and ICA was 15.98 ± 8.54. (p= 0.745) indicating a statistically insignificant difference between both modalities. Assessment of the SYNTAX score for the LAD by MSCT CA showed a mean score of 13.36 ± 7.30 and by ICA was 12.71 ± 7.79 (p = 0.280) indicating a statistically insignificant difference between both modalities. The SYNTAX for the LCX by MSCT CA was 4.08 ± 2.52 and by ICA was 5.00 ± 4.21 (p=0.324) indicating a statistically insignificant difference between both modalities. MSCT CA calculation of RCA Syntax was 7.55 ± 3.35 and by ICA was 7.32 ± 3.68 (p value = 0.299) indicating a statistically insignificant difference between both modalities. The mean SYNTAX per lesion using CT was 7.98 ± 6.9 and using CAwas 7.85 ± 6.8 p = 0.219 indicating a statistically insignificant difference at the level of analyzing the SYNTAX for the aforementioned means by both modalities. A lesion based analysis compared 78 lesions that were identified by both modalities for individual parameters of the SYNTAX score. A near perfect agreement was seen with regards to the number of total occlusions, bifurcation, trifurcation and tortuous lesions with a kappa Value of 1. Long lesions also showed a substantial agreement with a Kappa of 0.779. Calcified lesions were only identified by CT whereas thrombi filled lesions were only seen by ICA denoting no agreement of both techniques. Sub analysis of bifurcation lesions looking at Medina Class and total occlusions looking at blunt stump and first segment visible to total occlusion also revealed an almost perfect agreement with Kappa values of 0.964, 0.965 respectively.) Based on our results we believe that clinical decisions based on SYNTAX score calculated from MSCT CA may be recommended and can have impact on reducing hospital stay, establishing a heart team recommendation prior to ICA and reducing total cost and risk of complications by planning an ad hoc procedure rather than deferring the patient for intervention in another session if necessary.