SPC365

Coronary CT as a First-Line Strategy for Bypass Graft Assessment: Diagnostic Concordance and Predictors of Occlusion

Session: Sessão de Posters 28 - Do diagnóstico à decisão: cuidados orientados por imagem na era moderna
Speaker: Raquel Fernandes da Silva

Congress: CPC 2026
Topic: B. Imaging
Theme: 03. Imaging
Subtheme: 03.2 Computed Tomography
Session Type: Posters Eletrónicos
FP Number: ---
Authors: Raquel Fernandes da Silva; Marta Paralta de Figueiredo; Diogo Brás; Gustavo Sá Mendes; David Neves; Ângela Bento; Renato Fernandes; Rita Caldeira da Rocha; Manuel Trinca; Lino Patrício

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><strong>Background</strong></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">Assessment of coronary bypass graft patency is essential in symptomatic post-CABG patients. While invasive coronary angiography (ICA) is the reference standard, coronary CT angiography (CTCA) provides a non-invasive alternative. Robust real-world evidence on diagnostic accuracy and predictors of graft occlusion remains limited.</span></span></span></p>

<p>&nbsp;</p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><strong>Objectives</strong></span></span></span><br />
<span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">To evaluate diagnostic agreement between CTCA and ICA for graft occlusion, report sensitivity/specificity metrics, and identify predictors of graft occlusion and discordance.</span></span></span></p>

<p>&nbsp;</p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><strong>Methods</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">Retrospective cohort of 35 post-CABG patients (72 grafts) who underwent CTCA and ICA. Grafts were classified by type (arterial vs venous) and coronary territory. OM and secondary branch grafts in this cohort were predominantly venous. Occlusion was considered only when complete graft occlusion was present on the reference test. Concordance was assessed with Cohen&rsquo;s kappa and chi-square; diagnostic accuracy (sensitivity, specificity, positive and negative predictive values) was calculated. Predictors of occlusion and patterns of discordance (CTCA under- or overestimation) were analysed.</span></span></span></p>

<p>&nbsp;</p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><strong>Results</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">Among 72 grafts (52.8% arterial, 47.2% venous), ICA identified 16 occlusions (22.2%). Venous grafts demonstrated markedly higher occlusion rates than arterial grafts (41.2% vs 5.3%; </span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><em>p</em></span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">&lt;0.001). CTCA showed excellent agreement with ICA (concordance 93.1%; Cohen&rsquo;s kappa = 0.877, </span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><em>p</em></span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">&lt;0.001). Diagnostic performance of CTCA for detecting complete graft occlusion: sensitivity 87.5%, specificity 98.2%, PPV 93.3%, NPV 96.5%. Overall discordance was low (6.9%), mainly due to CTCA underestimation (5.6%). Coronary territory significantly influenced occlusion prevalence (higher in OM and secondary branches; </span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><em>p</em></span></span></span><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">=0.003), but neither graft type nor territory predicted CTCA&ndash;ICA discordance.</span></span></span></p>

<p>&nbsp;</p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000"><strong>Conclusion</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Arial,sans-serif"><span style="color:#000000">CTCA demonstrates very high diagnostic accuracy for detection of complete bypass graft occlusion with excellent agreement with ICA and high sensitivity and specificity. Venous grafts and specific territories bear greater occlusion burden, yet CTCA performance remains robust across types and territories. These findings support the use of CTCA as a reliable first-line imaging strategy in symptomatic post-CABG patients, with potential to reduce diagnostic ICA in selected cases.</span></span></span></p>