Research article

Comparison of flow characteristics and vascular reactivity of radial artery and long saphenous vein grafts [NCT00139399]

William CF Chong¹ , Peter Collins^2,3 , Carolyn M Webb^2,3 , Anthony C De Souza¹ , John R Pepper¹ , Christopher S Hayward^2,3,4 and Neil E Moat¹

¹  Department of Cardiothoracic Surgery, Royal Brompton and Harefield NHS Trust, London, UK

²  Department of Cardiology, Royal Brompton & Harefield NHS Trust, London, UK

³  Cardiac Medicine, National Heart and Lung Institute, Imperial College London, London, UK

⁴  Department of Cardiology, St Vincent's Hospital and Victor Chang Cardiac Research Institute, Sydney, Australia

author email corresponding author email

Journal of Cardiothoracic Surgery 2006, 1:4doi:10.1186/1749-8090-1-4

Published:	3 March 2006

Abstract

Background

The morphological and functional differences between arteries and veins may have implications on coronary artery bypass graft (CABG) survival. Although subjective differences have been observed between radial artery (RA) and long saphenous venous (LSV) grafts, these have not been quantified. This study assessed and compared the flow characteristics and in-vivo graft flow responses of RA and LSV aorto-coronary grafts.

Methods

Angiograms from 52 males taken 3.7 ± 1.0 months after CABG surgery were analyzed using adjusted Thrombolysis in Myocardial Infarction (TIMI) frame count. Graft and target coronary artery dimensions were measured using quantitative coronary angiography. Estimated TIMI velocity (V_E) and volume flow (F_E) were then calculated. A further 7 patients underwent in-vivo graft flow responses assessments to adenosine, acetylcholine and isosorbide dinitrate (ISDN) using intravascular Doppler.

Results

The V_E for RA grafts was significantly greater than LSV grafts (P = 0.002), however there was no difference in volume F_E (P = 0.20). RA grafts showed positive endothelium-dependent and -independent vasodilatation, and LSV grafts showed no statistically significant response to adenosine and acetylcholine. There was no difference in flow velocity or volume responses. Seven RA grafts (11%) had compromised patency (4 (6%) ≥ 50% stenosis in the proximal/distal anastomoses, and 3 (5%) diffuse narrowing). Thirty-seven (95%) LSV grafts achieved perfect patency and 2 (5%) were occluded.

Conclusion

The flow characteristics and flow responses of the RA graft suggest that it is a more physiological conduit than the LSV graft. The clinical relevance of the balance between imperfect patency versus the more physiological vascular function in the RA graft may be revealed by the 5-year angiographic follow-up of this trial.