Impact of the size mismatch between saphenous vein graft and coronary artery on graft patency.

BACKGROUND

The saphenous vein graft (SVG) is widely used in coronary artery bypass grafting because of its availability and ease of use. However, the patency rate of the SVG grafted to the right coronary artery (RCA) is poor. Diameter mismatch between the coronary artery and SVG is an important cause of graft occlusion. In this study, we assessed how the degree of diameter mismatch affects SVG patency.

METHODS

We reviewed the records of 123 patients who underwent aorto-right coronary artery bypass grafting with an SVG. The patency rate of the SVG, SVG diameter, RCA diameter and SVG-RCA diameter ratio (SR ratio) was assessed based on angiography and CT.

RESULTS

The mean SVG diameter was 3.61 ± 0.72 mm, the mean RCA diameter was 1.57 ± 0.32 mm and the mean SR ratio was 2.37 ± 0.57. Cumulative patency rate of the SVG was 95.5 % at the early phase, 85.2 % at 1 year, and 70.2 % at 5 years. Multivariate analysis showed that the SR ratio was an independent predictor of SVG occlusion. The cutoff value of the SR ratio was 2.8, calculated from the point of maximal specificity (81.2 %) and sensitivity (64.7 %), and the area under the ROC curve was 0.734. When the SR ratio was ≤2.8, the 3-year patency rate was 86.1 %.

CONCLUSIONS

A mismatch between SVG diameter and RCA diameter has an impact on the patency rate of the SVG. Evaluation of the saphenous vein before surgery and selection of a graft to minimize mismatch should improve SVG patency.