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Patency of Radial-Artery vs. Saphenous-Vein Bypass Grafts

Overall, patency was better with radial-artery grafts, but longer follow-up and comparison with right internal artery grafts are needed.

Which is a better conduit for coronary artery bypass grafting (CABG), the radial artery or the saphenous vein? To find out, researchers conducted a multicenter, randomized trial involving 561 patients (age, <80; estimated LV ejection fraction, >35%) with triple-vessel disease who were undergoing nonemergency CABG with a left internal mammary graft to the left anterior descending coronary artery.

All subjects underwent both radial-artery and saphenous-vein grafting, with the target vessel chosen randomly in the operating room. If the radial-artery graft was paired with the left circumflex artery, then the saphenous-vein graft was paired with the right coronary artery, and vice versa. (This design allowed each patient to be his or her own control.) Additional grafts were permitted as necessary. All patients had native-vessel stenosis 70%. Postoperative drug therapy included aspirin and calcium-channel blockade.

At 8 to 12 months postsurgery, 78% of patients underwent follow-up angiography. Complete graft occlusion was significantly more common with saphenous-vein grafts (13.6%) than with radial-artery grafts (8.2%). However, an angiographic "string" sign (diffuse narrowing to <1 mm) was evident in significantly more radial-artery (7.0%) than saphenous-vein (0.9%) grafts. For radial-artery grafts, complete occlusion and diffuse narrowing were significantly less common when native-vessel stenosis was 90% than when it was 70% to 89%; for saphenous-vein grafts, the difference was not significant. Adverse clinical events were no more likely to be associated with one type of graft or the other.

Comment: This study's unique design was intended to minimize differences in patient characteristics, surgical technique, concurrent medications, and angiographic follow-up. A major finding is that radial-artery graft patency is influenced by the severity of proximal native-vessel stenosis: The grafts are more likely to occlude if there is less flow in the bypassed vessel. Overall, patency was better with radial-artery grafts than with saphenous-vein grafts. The importance of the higher incidence of string signs in the radial-artery grafts is debatable; the authors note that this sign is not often associated with ischemia, and may improve with time. However, an accompanying perspective piece suggests that 5-year follow-up is needed to prove this point and raises the possibility that right internal artery grafts may be as good as or better than radial-artery grafts.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology January 7, 2005

Citation(s):

Desai ND et al. for the Radial Artery Patency Study Investigators. A randomized comparison of radial-artery and saphenous-vein coronary bypass grafts. N Engl J Med 2004 Nov 25; 351:2302-9.

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• Medline abstract (Free)

Lytle BW. Prolonging patency -- Choosing coronary bypass grafts. N Engl J Med 2004 Nov 25; 351:2262-4.

• Original article (Subscription may be required)
• Medline abstract (Free)