COMPARISON OFARTERIAL ANDVENOUSGRAFTSINCORONARY ARTERY BYPASSGRAFT(CABG)SURGERYPATIENTSASSESSEDON COMPUTEDTOMOGRAPHYANGIOGRAPHY(CTA)

Abstract

Coronary artery bypass grafting (CABG) remains the gold standard for the treatment of multivessel coronary artery disease, yet long-term success largely dependsongraft patency. Arterial conduits such as the left internal thoracic artery (LITA) offer superior durability, whereas venous grafts like the saphenous vein graft (SVG) are more prone to stenosis, occlusion, and aneurysmal changes. Regional data from South Asia remain scarce, particularly regarding the comparative outcomes of arterial and venous grafts and the influence of demographic, clinical, and anatomical factors. This study aimed to evaluate graft patency and long-term outcomes in post-CABG patients using multidetector computed tomography angiography (MDCTA), with a specific focus on graft type, anatomical parameters, comorbidities, and sociodemographic influences. This study adopted a cross-sectional prospective design and was conducted at the National Institute of Cardiovascular Diseases (NICVD) Karachi, Tando MuhammadKhan(TMK),Sukkur, and the Neurospinal and Cancer Care Institute (NCCI), in collaboration with the Bahria University Health Sciences Campus Karachi (BUHSCK). A purposive sample of 59 post-CABG patients, aged 35–79 years, who presented to the emergency room or outpatient department with cardiac symptoms such as chest pain, dyspnea, or arrhythmias, was included. Patients underwent (MDCTA) using a 128-slice Siemens SOMATOM Definition Edge scanner to assess graft patency, stenosis, or occlusion. Clinical and demographic data, comorbidities, echocardiographic findings (mitral and aortic regurgitation, Left Ventricular End Diastolic diameter (LVED), and extracardiac anatomical parameters (pericardial thickness, sternal–RV distance, and cardiac xi dominance) were recorded. Patient preparation included fasting, beta-blockers, and sublingual nitroglycerin as appropriate, with iohexol contrast administered intravenously. Image reconstruction and analysis were performed using syngo.via software with multiplanar and 3D techniques to evaluate graft lumen status and measure luminal diameters. Ethical approval was obtained from institutional review boards, and informed consent was secured from all participants. The study duration spanned two years, with data collection over seven months and subsequent analysis. Among arterial grafts, LITA demonstrated superior long-term patency, with only 8.6% showing occlusion or calcification, compared to 33.6% of venous grafts. Venous grafts were more frequently stenosed (42.1%) and demonstrated a higher prevalence of aneurysmal or ectatic changes compared to arterial conduits. Patient demographics revealed a male predominance (89.7%), and middle socioeconomic groups comprised the majority (56%). Age significantly influenced venous graft status, with patients aged 60–69 years showing the highest rates of stenosis (45.7%). Comorbidities, particularly diabetes, hypertension, and their combinations, demonstrated a significant association with venous graft occlusion (p=0.013). Continuous variable analysis revealed that arterial graft diameters averaged 1.95–2.0 mm, while venous grafts averaged 2.1–2.3 mm, with venous diameters varying more widely. BMI and LVED values showed modest but important associations with graft outcomes; higher BMI correlated with venous graft stenosis, while LVED remained relatively preserved across groups. Extracardiac changes such as increased pericardial thickness (>4 mm) and greater sternal distances showed trends toward association with venous graft failure but did not reach strong statistical significance. Importantly, anatomical site of anastomosis was strongly linked with graft outcome. Distal anastomoses showed the highest proportion of patent grafts (50.8%), whereas middle and marginal sites were more frequently stenosed or occluded (p<0.001). Native coronary vessels also demonstrated progression of atherosclerosis post-CABG, with venous graft-dependent territories showing higher calcification and mid xii segment stenosis. This study highlights the superior long-term outcomes of arterial grafts compared to venous grafts in South Asian post-CABG patients, reinforcing the importance of arterial-first strategies in surgical planning. MDCTA proved to be a reliable, noninvasive modality for long-term graft surveillance. The inclusion of clinical, demographic, and anatomical predictors—such as graft diameter, LVED, BMI, pericardial thickness, and site of anastomosis—adds novelty and practical value to patient-specific follow-up. As the first multicenter study in Pakistan to assess graft patency in relation to sociodemographic and anatomical factors, these findings emphasize the need for individualized surgical strategies, closer monitoring of venous grafts, and long-term region-specific follow-up programs.