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Page 2 of 10 Naik et al. Vessel Plus 2018;2:38 I http://dx.doi.org/10.20517/2574-1209.2018.62

Conduits available in CABG can be broadly classified into arterial and venous grafts. Saphenous vein (SV),
Internal Thoracic Artery (ITA), Radial Artery (RA), Ulnar Artery (UA), and right gastroepiploic artery can
[3,4]
be used as grafts . Venous grafts have been found to be more prone to thrombosis, intimal hyperplasia,
[5]
and atherosclerosis in comparison with arterial grafts . Arterial grafts are thus more widely preferred over
[6]
venous grafts .
[7]
The RA has been suggested as a suitable conduit for CABG in the 70’s in virtue of advantages like uniform
[8]
size and easy availability . Its use was initially abandoned due to concerns of vasospasm, but progressively
reconsidered in light of the positive long-term results described in the last decade. At least 6 randomized
clinical trials and several observational studies have positively compared patency rates and outcomes of RA
vs. RITA and saphenous vein graft (SVG), and very recent evidence from a large patient-level meta-analysis
[9]
has declared the actual “renaissance” of the RA . Bilateral internal thoracic artery (BITA) grafting is not
widely used due to a higher incidence of sternal complications when compared to single internal thoracic
artery grafting (SITA) (0.6% vs. 1.9%, 95% CI: 1.5-6.8) which necessitates additional measures to improve
prognosis. Current recommendations are:

Use of ITA in left anterior descending (LAD) bypass in patients where benefits greatly outweigh risks, i.e.,
when the procedure has to be performed.

An alternative to LITA should be used in patients where benefits outweigh risks, i.e., when additional studies
with broad objectives are required.

BITA should be considered in cases where risk of sternal complications is minimal and benefits outweigh
risks, i.e., when additional studies with broad objectives are required.

Risk of infection with BITA, should be reduced by skeletonizing the grafts, encouraging smoking cessation,
[10]
having tight glycemic control, and ensuring adequate sternal stabilization .

Both endoscopic and open techniques are available options for RA harvesting and carry different advantages
and complications.

This review will focus on RA and will examine the main features of this conduit along with the impact of
the available harvesting techniques on clinical outcomes.

PREOPERATIVE CONSIDERATIONS
While there are no major absolute contraindications to the use of RA, some disadvantages include its
increased tendency to spasm owing to a thick tunica media. It is also associated with higher risk of
[3]
atherosclerosis and intimal hyperplasia compared to ITA . Despite initial reports of lower patency rate
of RA grafts in diabetic patients when compared to SVG at 1 year (89.28% were patent in RA vs. 97.05%
[11]
patent in SVG) , the more recent literature and the results of a large patient-level meta-analysis confirm
the suitability of RA in diabetics and its theoretical advantage in terms of sternal wound infections when
compared to BITA [9,12,13] .

Pre-operative suitability of the radial artery is most commonly assessed by the modified Allen’s test which is
used to determine the patency of the vessels supplying the hand. If the patient’s hand flushes within 5-15 s after
the examiner releases the occlusive pressure applied on both the RA and the UA, it is considered a positive
modified Allen’s test. If the hand takes longer than 15 s the test is considered negative. A positive modified
[14]
Allen’s test translates into good blood circulation in the forearm . However, the reliability of this test has
[15]
been repeatedly questioned. Jarvis et al. recommended a Doppler ultrasound to be the gold standard. They