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Role of Radial Artery Graft in Coronary Artery Bypass Grafting

2005; Elsevier BV; Volume: 79; Issue: 6 Linguagem: Inglês

10.1016/j.athoracsur.2004.07.049

1552-6259

Lokeswara Rao Sajja, Gopichand Mannam, Narasinga Rao Pantula, Sriramulu Sompalli,

Aortic Disease and Treatment Approaches

The use of the radial artery (RA) as a coronary artery bypass graft has assumed a revival and thus a multitude of issues have arisen surrounding the routine and widespread use of this conduit in myocardial revascularization. There has been no uniformity regarding harvest techniques, assessment of the adequacy of hand collateral circulation, antispasm protocols, selection of target vessels, and the site of proximal anastomosis. It is widely believed and practiced that the RA should be harvested as a pedicle graft and preferably be used to bypass critically stenosed (>70% stenosis) coronary arteries. It is used either as a free graft with proximal anastomosis to the ascending aorta or as a composite arterial graft along with the left or right internal thoracic artery. The patency of RA grafts depends on the severity of the target coronary artery stenosis and target artery location rather than its use as an aortocoronary conduit or composite graft. In this article, we reviewed the current knowledge regarding the use of RA grafts as a coronary bypass conduit in an attempt to suggest a few acceptable strategies concerning the above issues in a given clinical scenario. The use of the radial artery (RA) as a coronary artery bypass graft has assumed a revival and thus a multitude of issues have arisen surrounding the routine and widespread use of this conduit in myocardial revascularization. There has been no uniformity regarding harvest techniques, assessment of the adequacy of hand collateral circulation, antispasm protocols, selection of target vessels, and the site of proximal anastomosis. It is widely believed and practiced that the RA should be harvested as a pedicle graft and preferably be used to bypass critically stenosed (>70% stenosis) coronary arteries. It is used either as a free graft with proximal anastomosis to the ascending aorta or as a composite arterial graft along with the left or right internal thoracic artery. The patency of RA grafts depends on the severity of the target coronary artery stenosis and target artery location rather than its use as an aortocoronary conduit or composite graft. In this article, we reviewed the current knowledge regarding the use of RA grafts as a coronary bypass conduit in an attempt to suggest a few acceptable strategies concerning the above issues in a given clinical scenario. Since its reintroduction by Acar and colleagues [1Acar C. Jebara V.A. Portoghese M. et al.Revival of the radial artery for coronary artery bypass grafting.Ann Thorac Surg. 1992; 54: 652-660Abstract Full Text PDF PubMed Scopus (655) Google Scholar], the radial artery (RA) has generated considerable interest as an alternative arterial conduit for coronary artery bypass grafting (CABG). The resurgence of interest in the use of RA has been a sequelae to well-documented incidence of saphenous vein graft failure in the long-term [2Salomon N.W. Page U.S. Bigelow J.C. Krause A.H. Okies J.E. Metzdorff M.J. Reoperative coronary surgery comparative analysis of 6591 patients undergoing primary bypass and 508 patients undergoing reoperative coronary artery bypass.J Thorac Cardiovasc Surg. 1990; 100: 250-259PubMed Google Scholar]. In addition the exceptional results observed with arterial conduits, such as the left internal mammary artery (LIMA) anastomosed to the left anterior descending (LAD) artery, prompted the use of the RA as a second arterial conduit [3Loop F.D. Lytle B.W. Cosgrove D.M. et al.Influence of the internal mammary artery graft on 10-year survival and other cardiac events.N Engl J Med. 1986; 314: 1-6Crossref PubMed Scopus (2304) Google Scholar, 4Tatoulis J. Buxton B.F. Fuller J.A. Patencies of 2127 arterial to coronary conduits over 15 years.Ann Thorac Surg. 2004; 77: 92-107Abstract Full Text Full Text PDF Scopus (362) Google Scholar]. The RA graft is rapidly gaining popularity because of its diameter, length, safety, and ease of harvest as well as the encouraging early and mid-to-long-term results [5Acar C. Ram Sheyi A. Pogny J.Y. et al.The radial artery for coronary artery bypass grafting clinical and angiographic results at five years.J Thorac Cardiovasc Surg. 1998; 116: 981-989Abstract Full Text Full Text PDF PubMed Scopus (324) Google Scholar, 6Possati G. Gaudino M. Alessandrini F. et al.Midterm clinical and angiographic results of radial artery grafts used for myocardial revascularization.J Thorac Cardiovasc Surg. 1998; 116: 1015-1021Abstract Full Text Full Text PDF PubMed Scopus (164) Google Scholar, 7Calafiore A. Di Giammarco G. Teodori G. et al.Radial artery and inferior epigastric artery in composite grafts improved midterm angiographic results.Ann Thorac Surg. 1995; 60: 517-523Abstract Full Text PDF PubMed Scopus (185) Google Scholar, 8Iacó A.L. Teodori G. Di Giammarco G. et al.Radial artery for myocardial revascularization long-term clinical and angiographic results.Ann Thorac Surg. 2001; 72: 464-469Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar]. It is being used as a conduit of choice over the right internal mammary artery (RIMA) by many surgeons because of the absence of additional risks regarding sternal wound infections, because no differences exist in perioperative or intermediate-term cardiac morbidity and mortality rates, and because the RA indicates equally favorable early and midterm patency rates [9Borger M.A. Cohen G. Buth K.J. et al.Multiple arterial grafts.Radial versus right internal thoracic arteries. Circulation. 1998; 98: II-7-II-14Google Scholar]. We have reviewed the recent literature on the use of RA as a coronary artery bypass conduit. We searched the PubMed database using the following phrases: “RA graft in coronary artery bypass,” “spasm of radial artery,” and “forearm function after radial artery harvest.” Articles published between 1978 and 2003 were analyzed to summarize the current knowledge regarding the use of this conduit with special reference to surgical anatomy, harvest techniques, antispasm protocols, selection of target arteries, and the site of proximal anastomosis. A few selected papers on each one of the abovementioned issues were analyzed and cited. CABG using the RA was introduced clinically by Carpentier and colleagues in 1973 [10Carpentier A. Guermonprez J.L. Deloche A. Frechette C. Dubost C. The aorta-to-coronary radial artery bypass graft a technique avoiding pathological changes in the graft.Ann Thorac Surg. 1973; 16: 111-121Abstract Full Text PDF PubMed Scopus (471) Google Scholar]. Despite early promising clinical outcomes, 2 years later in 1975 Carpentier himself recommended that this procedure be abandoned because of the higher incidence (35%) of narrowing or occlusion [11Carpentier A. Geha A.S. Krone R.J. Mc Cormick J.R. Baue A.E. Discussion of selection of coronary bypass anatomic, physiological and angiographic considerations of vein and mammary grafts.J Thorac Cardiovasc Surg. 1975; 70: 414-431PubMed Google Scholar]. In 1989 Acar and colleagues reviewed the late angiograms performed on an early series of patients studied by Carpentier and to their surprise determined that the radial grafts were patent and functioning well at 15 years which were previously thought to be occluded. Acar attributed this early graft failure to the spasm of radial arteries and introduced pharmacological measures to minimize arterial spasms. In addition, Acar also refined the harvest techniques. Together, these changes resulted in the revival and interest regarding the use of this conduit for CABG [1Acar C. Jebara V.A. Portoghese M. et al.Revival of the radial artery for coronary artery bypass grafting.Ann Thorac Surg. 1992; 54: 652-660Abstract Full Text PDF PubMed Scopus (655) Google Scholar]. The RA is the smaller of the two terminal branches of the brachial artery. It ascends from the brachial artery in the cubital fossa approximately 1.0 cm below the bend of the elbow opposite the neck of the radius and is a more direct continuation of the brachial artery. After its origin it traverses through the lateral aspect of the forearm approaching its lower end where it enters the palm to anastomose with the deep branch of the ulnar artery to complete the formation of the deep palmar arch. The proximal RA courses underneath the muscle belly of the brachioradialis muscle and, at this junction, prudence is required to identify and spare the lateral antebrachial cutaneous nerve that lies over the belly of the brachioradialis muscle. Damage to this nerve is associated with parasthesias of the radial side of the ventral aspect of the forearm [12Reyes A.T. Frame R. Brodman R.F. Technique of harvesting the radial artery as a coronary artery bypass graft.Ann Thorac Surg. 1995; 59: 118-126Abstract Full Text PDF PubMed Scopus (132) Google Scholar]. The other important structure in proximity to RA is the median nerve, which is positioned near the most proximal part of the RA and distal part of the brachial artery and should be safeguarded during the harvest. The mid-part of the RA lies near the superficial branch of the radial nerve that is situated under the brachioradialis muscle. In its distal third, the artery becomes superficial and is positioned anterior to the radius and pronator quadratus muscle between the tendons of the brachioradialis and flexor carpi radialis. The structural relationships of RA are indicated in Figure 1. Several variations regarding the termination of the radial and ulnar arteries are common. Although the classic type of superficial palmar arch occurs relatively infrequently, there are always considerable anastomoses between the radial and ulnar arteries in the hand. Two types of deep palmar arches (complete and incomplete) and two types of superficial palmar arches (complete and incomplete) and their variants were described in detail in a study by Ruengsakulrach and colleagues [13Ruengsakulrach P. Eizenberg N. Fahrer C. Fahrer M. Buxton B.F. Surgical implications of variations in hand collateral circulation.Anatomy revisited: J Thorac Cardiovasc Surg. 2001; 122: 682-686Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar]. RA was classified as a type 3 arterial graft with higher propensity to spasm [14He G.W. Arterial grafts for coronary artery by pass grafting biological characteristics functional classification and clinical choice.Ann Thorac Surg. 1999; 67: 277-284Abstract Full Text Full Text PDF PubMed Scopus (144) Google Scholar]. The medial thickness of RA is substantially greater than other arterial conduits such as the internal mammary artery (IMA) or the gastroepiploic artery (GEA) [15He G.W. Yang C.Q. Comparative study on calcium channel antagonists in the human radial artery clinical implication.J Thorac Cardiovasc Surg. 2000; 119: 94-100Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar]. The RA exhibits a greater contraction force to potassium chloride than the IMA or GEA and a higher contraction force to norepinephrine and serotonin than the IMA but not the GEA [16Chardigny C. Jebare V.A. Acar C. et al.Vasoreactivity of the radial artery Comparison with the internal mammary and gastroepiploic arteries with implications for coronary artery surgery.Circulation. 1993; 88: 115-127Google Scholar]. In patients with coronary artery disease, RA atherosclerotic involvement is more frequent than that of the internal thoracic artery (ITA), but far less than of the common carotid artery. The early atherosclerotic changes observed in the RA do not seem to exhibit the potential to influence RA graft patency and endothelial function [17Gaudino M. Tondi P. Serricchio M. et al.Atherosclerotic involvement of the radial artery in patients with coronary artery disease and its relation with mid-term radial artery raft patency and endothelial function.J Thorac Cardiovasc Surg. 2003; 126: 1968-1971Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar]. Hagiwara and associates reported that structural changes rarely develop in RA grafts even at midterm [18Hagiwara H. Ito T. Kamiya H. Akita T. Usui A. Veda Y. Midterm structural changes in the radial artery grafts after coronary artery bypass.Ann Thorac Surg. 2004; 77: 805-810Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar]. It is mandatory to assess the adequacy of the ulnar collateral circulation of the hand before harvesting RA. The Allen test is the most frequently used screening method for the evaluation of the adequacy of collateral hand circulation. The Allen test is considered positive if the reperfusion of thenar eminence, thumb, and index finger does not occur even at 10 seconds after the release of occlusion of the ulnar artery while maintaining the occlusion of the RA at the wrist joint. An intraoperative Allen test may be useful in the presence of the high origin of the superficial palmar branch or an anomalous anterior interosseous artery when a preoperative Allen test can be falsely negative [19Buxton B.F. Windsor M. Komeda M. Gaer J. Fuller J. Liu J. How good is the radial artery as a bypass graft.Coronary Artery Dis. 1997; 8: 225-233Crossref PubMed Scopus (26) Google Scholar]. Another method employed to assess the adequacy of hand collateral circulation includes use of a continuous wave Doppler placed on the superficial palmar arch to observe whether RA compression results in a decrease in the audibility of palmar arch signals. A decrease in audible Doppler signals with RA compression is considered to be a positive modified Allen test. No change or increase in the signals is considered as a negative test [20Wolk S.W. Mores H.K. Lampman R.H. et al.The use of pre-operative non-invasive vascular studies for evaluation of radial artery conduits for coronary artery bypass grafting.Vasc Surg. 1998; 32: 249-253Crossref Scopus (5) Google Scholar]. Another modification of the Allen test is the measurement of the first and second digit pressures before and during RA compression with a 2.5 cm digit pressure cuff placed on the proximal phalanx. Decrease in the systolic digit pressure of 40 mm Hg or more (digit δ p) in either digit with RA compression is considered a positive test [21Starnes S.L. Wolk S.W. Lampman R.M. et al.Noninvasive evaluation of hand circulation before radial artery harvest for coronary artery bypass grafting.J Thorac Cardiovasc Surg. 1999; 117: 261-266Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar]. Oxymetric plethysmographic waveform analysis is also used to assess the adequacy of ulnar collateral circulation. Furthermore a combination of these methods can be used to assess the adequacy of the ulnar collateral system to avoid hand ischemia after RA harvest [22Sajja L.R. Mannam G. Sompalli S. Is Allen’s test not reliable in the selection of patients for radial artery harvest?.Ann Thorac Surg. 2002; 74: 296Abstract Full Text Full Text PDF PubMed Google Scholar]. Currently RA is accepted as a secondarily preferred arterial conduit for coronary revascularization subsequent to the left internal thoracic artery (LITA). The usual target arteries for its usage are obtuse marginal branches of the circumflex artery, ramus intermedius, and right coronary artery (RCA). RA has been increasingly used as a composite arterial conduit to achieve total arterial revascularization. The advantages of composite radial arterial graft include greater conduit length and minimizing aortic manipulation particularly so when coronary revascularization is performed on beating heart [7Calafiore A. Di Giammarco G. Teodori G. et al.Radial artery and inferior epigastric artery in composite grafts improved midterm angiographic results.Ann Thorac Surg. 1995; 60: 517-523Abstract Full Text PDF PubMed Scopus (185) Google Scholar, 23Johnson W.H. Cromartic R.S. Arrants J.E. Wuamette J.A. Holt J.M. Simplified method for candidate selection for radial artery harvesting.Ann Thorac Surg. 1998; 65: 1167Abstract Full Text Full Text PDF PubMed Google Scholar]. A positive Allen test is a contraindication for the RA harvest from the ipsilateral forearm. Approximately 11.6% of patients indicate a unilateral positive Allen test [24Brodman R.F. Frame R. Camacho M. Ha E. Chen A. Hollinger I Routine use of unilateral and bilateral radial arteries for coronary artery bypass graft surgery.J Am Coll Cardiol. 1996; 28: 959-963Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar]. A prior operation for carpal tunnel syndrome leads to periarterial fibrosis of the distal segment of the RA and may preclude its use. A previous RA cannulation at the wrist may cause periarterial fibrosis. However these RA conduits may still be useful as a conduit after discarding the few distal centimeters. The use of the RA as a bypass conduit after transradial catheterization should be managed cautiously, as intimal damage may have occurred during catheter manipulations [25Kamiya H. Ushijima T. Kanamori T. et al.Use of the radial artery graft after transradial catheterization is it suitable as a bypass conduit?.Ann Thorac Surg. 2003; 76: 1505-1509Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar]. Diffuse arteriosclerosis and medial calcification observed in the elderly is a contraindication for its use. However specks of calcium seen in the RA do not preclude its use. It is reported that RA is not an ideal conduit to bypass target arteries that indicate less critical (< 70%) stenosis because of the possibility of competitive flow that results in either complete occlusion or formation of “string sign” [26Royse A.G. Royse C.F. Tatoulis J. et al.Post operative radial artery angiography for coronary artery bypass surgery.Eur J Cardiothorac Surg. 2000; 17: 294-304Crossref PubMed Scopus (102) Google Scholar, 27Maniar H.S. Sundt III, T.M. Barner H.B. et al.Effect of target stenosis and location on radial artery graft patency.J Thorac Cardiovasc Surg. 2002; 123: 45-52Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar]. Most surgeons perform the RA harvest from the nondominant forearm [1Acar C. Jebara V.A. Portoghese M. et al.Revival of the radial artery for coronary artery bypass grafting.Ann Thorac Surg. 1992; 54: 652-660Abstract Full Text PDF PubMed Scopus (655) Google Scholar, 28Kulshrestha P. Rao L. Garb J.L. Rousou J.A. Engelman R.M. Wait R.B. Use of extrafascially harvested radial artery for coronary artery revascularization technical considerations.J Card Surg. 1999; 14: 26-31Crossref PubMed Scopus (17) Google Scholar] although others harvest bilateral radial arteries routinely [24Brodman R.F. Frame R. Camacho M. Ha E. Chen A. Hollinger I Routine use of unilateral and bilateral radial arteries for coronary artery bypass graft surgery.J Am Coll Cardiol. 1996; 28: 959-963Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar, 29Tatoulis J. Buxton B.F. Fuller J.A. Bilateral radial artery grafts in coronary reconstruction technique and early results in 261 patients.Ann Thorac Surg. 1998; 66: 714-720Abstract Full Text Full Text PDF PubMed Scopus (106) Google Scholar]. Occasionally a long length of RA can be divided into two segments to graft two separate targets [24Brodman R.F. Frame R. Camacho M. Ha E. Chen A. Hollinger I Routine use of unilateral and bilateral radial arteries for coronary artery bypass graft surgery.J Am Coll Cardiol. 1996; 28: 959-963Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar] or to construct multiple distal anastomoses in a sequential fashion [30da Costa F.D.A. da Costa I.A. Poffo R. et al.Myocardial revascularization with the radial artery a clinical and angiographic study.Ann Thorac Surg. 1996; 62: 475-479Abstract Full Text PDF PubMed Scopus (33) Google Scholar, 31Weinschelbaum E.E. Gabe E.D. Macchia A. Smimmo R. Suarez L.D. Total myocardial revascularization with arterial conduits radial artery combined with internal thoracic arteries.J Thorac Cardiovasc Surg. 1997; 114: 911-916Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar]. The RA has been used as an effective conduit in coronary reoperations [32Tatoulis J. Buxton B.F. Fuller J.A. The radial artery in coronary re-operations.Eur J Cardio Thorac Surg. 2001; 19: 266-272Crossref PubMed Scopus (10) Google Scholar]. The common technique of harvesting RA is along with venae committantes using low strength electrocautery as an open method [33Reyes A.T. Frame R. Bordman R.F. Technique for harvesting the radial artery as a coronary artery bypass graft.Ann Thorac Surg. 1995; 59: 118-126Abstract Full Text PDF PubMed Scopus (173) Google Scholar, 34Tatoulis J. Royse A.G. Buxton B.F. et al.The radial artery in coronary surgery A 5-year experience clinical and angiographic results.Ann Thorac Surg. 2002; 73: 143-148Abstract Full Text Full Text PDF PubMed Scopus (141) Google Scholar]. The extrafascial technique of harvesting has also been reported [28Kulshrestha P. Rao L. Garb J.L. Rousou J.A. Engelman R.M. Wait R.B. Use of extrafascially harvested radial artery for coronary artery revascularization technical considerations.J Card Surg. 1999; 14: 26-31Crossref PubMed Scopus (17) Google Scholar]. Other methods include harvesting the RA in a skeletonized fashion [35Amano A. Takahashi A. Hirose H. Skeletonized radial artery grafting improved angiographic results.Ann Thorac Surg. 2002; 73: 1880-1887Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar]. Connolly and associates [36Connolly M.W. Torrillo L.D. Stauder M.J. et al.Endoscopic radial artery harvesting results of first 300 patients.Ann Thorac Surg. 2002; 74: 502-505Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar] have popularized the endoscopic technique. The hemostasis during harvest is achieved with either low strength cautery [37Sajja L.R. Mannam G. Sompalli S. Neurological hand complications after radial artery harvest for coronary artery bypass grafting.J Thorac Cardiovasc Surg. 2002; 123: 585-586Crossref PubMed Google Scholar] or an ultrasonically activated scalpel [38Psacioglu H. Atay Y. Cetindag B. Saribulbul O. Buket S. Hamulu A. Easy harvesting of radial artery with ultrasonically activated scalpel.Ann Thorac Surg. 1998; 63: 984-985Abstract Full Text Full Text PDF Scopus (49) Google Scholar]. Locker and associates reported that the compound effect of RA harvesting with a harmonic scalpel and topical treatment with the α-blocking agent, regitine, increases RA free flow and markedly decreases intraoperative spasticity [39Locker C. Ben-Gal Y. Paz Y. et al.Technical aspects of harvesting the radial artery with harmonic scalpel.Heart Surg Forum. 2003; 6: 345-347PubMed Google Scholar]. Rukosujew and colleagues reported that skeletonization of the RA using scissors and clips is more time-consuming and technically more difficult, but yields considerably longer graft. Skeletonization with an ultrasonic scalpel did not result in additional length and was more frequently associated with severe endothelial damage [40Rukosujew A. Reichelt R. Fabricius A.M. et al.Skeletonization versus pedicle preparation of the radial artery with and without the ultrasonic scalpel.Ann Thorac Surg. 2004; 77: 120-125Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar]. Pedicle preparation using scissors or an ultrasonic scalpel is much simpler and faster and does not jeopardize endothelial integrity [40Rukosujew A. Reichelt R. Fabricius A.M. et al.Skeletonization versus pedicle preparation of the radial artery with and without the ultrasonic scalpel.Ann Thorac Surg. 2004; 77: 120-125Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar]. Usually the distal end of the RA is used for coronary anastomosis and the proximal end of the RA to the aorta or internal mammary artery. At times when the RA becomes sclerosed at the level of the wrist, this end may be used to create the proximal anastomosis and the healthy proximal part (elbow end) of the RA may be used for coronary anastomosis [41Locker C. Mohr R. Paz Y. et al.Pretreatment with X-adrenergic blocker for prevention of radial artery spasm.Ann Thorac Surg. 2002; 74: S1368-S1370Abstract Full Text Full Text PDF PubMed Google Scholar]. The RA is preferably grafted to the native coronary artery with stenosis greater than 70% to avoid the risk of competitive flow and the development of string sign. The usual targets are the left circumflex (LCx), ramus intermedius, or RCA. Numerous published studies indicate decreased RA patency rates when grafted to bypass the RCA [26Royse A.G. Royse C.F. Tatoulis J. et al.Post operative radial artery angiography for coronary artery bypass surgery.Eur J Cardiothorac Surg. 2000; 17: 294-304Crossref PubMed Scopus (102) Google Scholar, 27Maniar H.S. Sundt III, T.M. Barner H.B. et al.Effect of target stenosis and location on radial artery graft patency.J Thorac Cardiovasc Surg. 2002; 123: 45-52Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar]. If sequential grafting is required, the intermediate anastomoses can exhibit lower degree stenosis albeit that the last territory is severely stenosed [26Royse A.G. Royse C.F. Tatoulis J. et al.Post operative radial artery angiography for coronary artery bypass surgery.Eur J Cardiothorac Surg. 2000; 17: 294-304Crossref PubMed Scopus (102) Google Scholar]. The RA can be used as an aortocoronary bypass graft (free graft) [30da Costa F.D.A. da Costa I.A. Poffo R. et al.Myocardial revascularization with the radial artery a clinical and angiographic study.Ann Thorac Surg. 1996; 62: 475-479Abstract Full Text PDF PubMed Scopus (33) Google Scholar, 42Dietl C.A. Benoit C.H. Radial artery graft for coronary revascularization technical considerations.Ann Thorac Surg. 1995; 60: 102-109Abstract Full Text PDF PubMed Scopus (120) Google Scholar, 43Chen A.H. Nakao T. Brodman R.F. et al.Early postoperative angiographic assessment of radial artery grafts used for coronary artery bypass grafting.J Thorac Cardiovasc Surg. 1996; 111: 1208-1212Abstract Full Text Full Text PDF PubMed Scopus (108) Google Scholar] or as a composite Y or T graft extending from the LITA [44Calafiore A.M. Di Giammarco G. Luciani N. Maddestre N. Di Nardo E. Angclini R. Composite arterial conduits for a wider arterial myocardial revascularization.Ann Thorac Surg. 1994; 58: 185-190Abstract Full Text PDF PubMed Google Scholar]. Some groups have also described usage of the RA as an extension graft to the in situ right internal thoracic artery (RITA) or right gastroepiploic artery (RGEA) [45Sajja L.R. Mannam G. Right internal mammary artery and radial artery composite in situ pedicle graft in coronary artery bypass grafting.Ann Thorac Surg. 2002; 73: 1856-1859Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 46Kamiya H. Watanabe G. Takemura H. Tomita S. Nagamina H. Kanamori T. Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting.J Thorac Cardiovasc Surg. 2004; 127: 1151-1157Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar]. Composite arterial grafts with RA extending from the LITA are more vulnerable to detrimental effects of chronic native competitive flow and should be used only for target vessels with a stenosis greater than 80% [26Royse A.G. Royse C.F. Tatoulis J. et al.Post operative radial artery angiography for coronary artery bypass surgery.Eur J Cardiothorac Surg. 2000; 17: 294-304Crossref PubMed Scopus (102) Google Scholar, 27Maniar H.S. Sundt III, T.M. Barner H.B. et al.Effect of target stenosis and location on radial artery graft patency.J Thorac Cardiovasc Surg. 2002; 123: 45-52Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar]. In a recently published study Maniar and associates concluded that the site of the proximal anastomosis does not seem to influence the patency, but both the RA-to-aorta and composite conduits are sensitive to target location and stenosis [47Maniar H.S. Barner H.B. Bailey M.S. et al.Radial artery patency are aortocoronary conduits superior to composite grafting.Ann Thorac Surg. 2003; 76: 1498-1504Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar]. Different patterns of RA use in total arterial revascularization has been described [7Calafiore A. Di Giammarco G. Teodori G. et al.Radial artery and inferior epigastric artery in composite grafts improved midterm angiographic results.Ann Thorac Surg. 1995; 60: 517-523Abstract Full Text PDF PubMed Scopus (185) Google Scholar, 45Sajja L.R. Mannam G. Right internal mammary artery and radial artery composite in situ pedicle graft in coronary artery bypass grafting.Ann Thorac Surg. 2002; 73: 1856-1859Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 46Kamiya H. Watanabe G. Takemura H. Tomita S. Nagamina H. Kanamori T. Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting.J Thorac Cardiovasc Surg. 2004; 127: 1151-1157Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar, 48Tector A.J. Amundsen S. Schmal T.M. et al.Total arterial revascularization with T-grafts.Ann Thorac Surg. 1994; 57: 33-39Abstract Full Text PDF PubMed Scopus (217) Google Scholar, 49Quigley R.L. Weiss S.J. Highbloom R.Y. Pym J. Creative arterial bypass grafting can be performed on the beating heart.Ann Thorac Surg. 2001; 72: 793-797Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar, 50Christensen J.B. Lund J.T. Kassis E. Kelback H. Complete arterial coronary revascularization using radial artery conduit for double thoracic artery inlet flow arterial sling operation.Eur J Cardiothorac Surg. 2002; 21: 391-394Crossref PubMed Scopus (15) Google Scholar, 51Prifti E. Bonacchi M. Frati G. Proietti P. Giunti G. Leacche M. λ graft with the radial artery or free left internal mammary artery anastomosed to the right internal mammary artery flow dynamics.Ann Thorac Surg. 2001; 72: 1275-1281Abstract Full Text Full Text