Incidences of Coronary Artery Bypass Graft Failures at Waitemata District Health Board–A 3.5 Year Analysis

Abstract

Background: After coronary artery bypass graft (CABG) surgery, left internal mammary artery (LIMA) grafts have superior patency rates compared to saphenous-venous-grafts (SVG) that degenerate with time. We sought to assess graft failure in patients with prior CABG in our DHB. Methods: Patients who underwent CABG (± valve surgery) between October 2012 and March 2016 who re-presented for clinically-indicated repeat coronary angiography were included. Baseline demographics, clinical characteristics, grafts used and re-presentation reasons were analysed. A graft was deemed to have failed if it had ≥75% stenosis (very early in ≤3months, early ≤12months). Results: 28 consecutive patients were identified: 86% males (mean: age at surgery 67, BMI 28 kg/m2, eGFR 64 mL/min), 36% diabetics, 71% hypertensives, 75% dyslipidaemics and 11% current smokers. All had a LIMA graft, 89% (n = 25) SVG's and 11% (n = 3) had radial grafts. Mean time to re-presentation was 209 days (46% angina, 29% acute coronary syndrome, 14% VF arrest, 11% cardiac failure). 39% (n = 11) had graft failure [9 VG; 2 LIMA], the majority [91% (n = 10)] in ≤12 months; 55% (n = 6) in ≤3months (4 VG; 2 LIMA grafts). Males (p = 0.009) and hypertensive patients (p = 0.037) were more likely to re-present. Being male trended with ≤3months-graft-failure [p = 0.061]. No other clinical predictors for graft failure were observed. Conclusion: Our small study had a high incidence of early graft failure, possibly commoner in males (p = NS). A larger cohort may identify definite clinical predictors for failure.