MDCT coronary angiography for assessment of saphenous vein graft patency and associated clinical risk factors

Abstract Background Long-term failure of saphenous vein grafts (SVGs) continues to compromise the clinical success of coronary artery bypass graft (CABG) surgery, frequently resulting in recurrent myocardial ischemia and adverse cardiovascular events. Although invasive coronary angiography (ICA) remains the reference standard for evaluating graft patency, its invasive nature limits its use for routine postoperative assessment. Multidetector computed tomography coronary angiography (MDCT-CA) provides a noninvasive method for evaluating graft patency. This prospective study aimed to determine the diagnostic performance of MDCT-CA in evaluating SVG patency using ICA as the reference standard and to investigate clinical factors associated with graft occlusion. Results The study included 58 patients with previous CABG and 79 SVGs who underwent MDCT coronary angiography (MDCT-CA) and invasive coronary angiography (ICA), with an interval of 1–4 weeks between the two examinations. Grafts were classified as patent, significantly stenotic (≥ 50% luminal diameter reduction), or occluded, and agreement between MDCT-CA and ICA was assessed using Cohen’s kappa coefficient. Out of the 79 SVGs analyzed, 46 (58.2%) were patent, 8 (10.1%) were stenotic, and 25 (31.6%) were occluded, with the obtuse marginal artery representing the most frequent target vessel (48.1%). MDCT-CA demonstrated excellent agreement with ICA (κ = 0.974, P < 0.001). Compared with the invasive reference standard, MDCT-CA yielded a sensitivity of 100%, specificity of 97.9%, positive predictive value of 97.0%, negative predictive value of 100%, and overall diagnostic accuracy of 98.7%. Diabetes mellitus ( P = 0.001) and a postoperative duration exceeding 5 years ( P = 0.003) were significantly associated with graft occlusion on univariate analysis, whereas hypertension showed a borderline association ( P = 0.053). Age, sex, family history of CAD, smoking, and dyslipidemia were not significantly associated with graft occlusion. Conclusion MDCT-CA demonstrated excellent agreement and high diagnostic accuracy compared with ICA for the assessment of SVG patency. Diabetes mellitus and longer duration since CABG surgery were significantly associated with SVG occlusion on univariate analysis. These findings support the role of MDCT-CA as a noninvasive diagnostic modality for the evaluation of SVGs in clinically referred patients after CABG.