Radial Artery Grafts’ String-Sign – Role of Graft Spasm and Competitive Flow.
Chee F Chong1; Neil E Moat2; Peter Collins3
1Thoracic Unit, Department of Surgery, Raja Isteri Pengiran Anak Saleha (RIPAS) Hospital, Bandar Seri Begawan, BA 1710, Brunei Darussalam.
2Department of Cardiothoracic Surgery, Royal Brompton and Harefield NHS Trust, Sydney Street, London SW3 6NP.
3Department of Cardiac Medicine, National Heart and Lung Institute @ Imperial College of Science, Technology and Medicine, Dovehouse Street, London SW3 6LY.
Introduction: Radial artery graft is prone to vasospasm and a small proportion developed string-sign. We investigated the role of vasospasm and competitive flow in radial artery graft string-sign. Materials & Methods: From May 1998 to April 1999, 101 patients (mean age of 59.5 ± 7.1 yr) recruited to the RSVP trial, underwent coronary angiography at 3.7 ± 1.1 months after CABG. Result: A total of 193 grafts (71 radial artery grafts; 122 saphenous vein grafts) were screened. All radial artery grafts were patent, compared with 96% of saphenous vein grafts. Five saphenous vein grafts (4%) were totally occluded and another 1.6% had anastomotic narrowing. Five radial artery grafts (7%) had diffuse string-sign and another 4 (6%) had anastomotic narrowing. Radial artery graft with string-sign had a mean diameter of 1.14 ± 0.25 mm. All responded to nitrate infusion significantly with a mean diameter of 1.38 ± 0.34 mm (p=0.04). These diameter changes were still significantly smaller than the mean diameter of normal radial artery grafts (p<0.0001). Retrospective analyses of preoperative angiograms confirmed presence of non-significant stenosis (<70%) in 3 patients. Conclusion: Our findings indicated that competitive flow and diffuse graft vasospasm may contribute to the pathogenesis of radial artery graft string-sign.
Keywords: Radial artery, string-sign, competitive flow, vasospasm
Correspondence author: Mr Chee F Chong, Thoracic Unit, Department of Surgery, Raja Isteri Pengiran Anak Saleha Hospital, Bandar Seri Begawan, BA 1710, Brunei Darussalam
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Brunei Int Med J. 2017; 13 (2): 51-57