Should the radial artery be used as a bypass graft following radial access coronary angiography

The radial artery (RA) is often selected as the next conduit of choice following the internal thoracic artery for coronary artery bypass grafting operations (CABG). Radial access coronary angiography (RA-CA) has grown in popularity among cardiologists and has been advocated as the access route of choice for coronary angiography and intervention by many groups. However, sheath insertion and instrumentation may lead to structural and functional damage to the RA, which may preclude its use as a bypass conduit. The increasing use of RA-CA may therefore have an adverse effect on the ability to use the RA as a bypass conduit at subsequent CABG. To review this, a best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was: 'should the radial artery be used as a bypass conduit following radial access coronary angiography'? Altogether, 167 papers were found using the reported search; 11 papers were identified that provided the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these studies were tabulated. Acute RA occlusion occurs in 2.3-30.5% of patients undergoing RA-CA. While a significant number of occluded RA's show recanalization on early follow-up, markers of endothelial function such as intima-media thickening (IMT) and flow-mediated dilatation remain impaired. RA-CA causes structural injury to the RA with evidence of histological injury (including intimal hyperplasia, periarterial tissue/fat necrosis and adventitial inflammation) along with intimal tears and medial dissections evident along the entire length of the vessel. Only one paper directly assesses patency rates of RA's used as bypass grafts following RA-CA finding a significant adverse effect on graft patency (77% patency in RA-CA, compared with 98% in the control group). We recommend avoiding the RA as a bypass conduit if it has previously been used for RA-CA. In situations where conduit options are limited, if possible, the RA should be avoided for at least 3 months following RA-CA and it may be beneficial to assess the RA's patency and flow characteristics with Doppler ultrasound preoperatively.