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Eur J Cardiothorac Surg 1999;15:186-193
© 1999 Elsevier Science NL
a Department of Cardiothoracic Surgery, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
b Department of Anaesthesia, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
c Department of Occupational Therapy, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
Received 20 September 1998; received in revised form 9 December 1998; accepted 16 December 1998.
* Corresponding author. Suite 28, Private Medical Centre, P.O. Box 2135, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia. Tel.: +61-3-9342-8908; fax: +61-3-9342-8908; e-mail: alistair.royse@nwhcn.org.au or june.sherry@nwhcn.org.au
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Abstract |
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 Top Abstract Introduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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Key Words: Radial artery • Total arterial revascularization • Pedicled arterial revascularization
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Introduction |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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Many years later Acar [3] described a number of these patients returning for angiography with patent RA grafts and, what is more, the grafts appeared disease free. This led to their series which revived interest in this conduit worldwide. Their improved results were attributed to more meticulous harvest technique, avoidance of metal probes as a means of vasodilation and the use of prophylactic systemic vasodilators commencing during the operation and continued indefinitely, postoperatively. Most subsequent papers have made reference to these conclusions [4][5][6].
The purpose of this paper is to describe our technique for RA harvest and to provide data on how it has been used, and the functional outcome in the hand and forearm.
As a consequence of the greater availability of arterial conduit offered by the RA, most of the patients at our institution now receive total arterial revascularization (TAR).
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Methods and materials |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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Technique of radial artery harvest
Preoperative Allen's test
Patients with prior hand or forearm surgery or major injury or patients with severe collagen vascular disorder do not have RA harvested. Patients with chronic renal failure are generally not excluded, since arterio–venous fistulae are now usually brachial.
The ulnar and radial arteries are compressed at the wrist for 
30 s to induce hand ischaemia. Blood is evacuated from the hand by clenching. The ulnar artery is released and if hyperaemic reperfusion at the tips of the thumb and index fingers occurs 
5 s then the test is called `normal' and the RA harvested. If reperfusion occurs 6–10 s then the test is called `equivocal' and mostly the RA is used. But if the reperfusion occurs >10 s then the test is deemed `abnormal' and RA is not used.
Radial artery harvest technique
The arm and chest are prepared and draped together. The arm must be placed on an arm board attached to the operating table so that no traction on the arm occurs when the table height is varied.
The incision extends from 1 cm medial and distal to the biceps tendon at the elbow to 1 cm medial and proximal to the radial styloid process.
Diathermy is used to divide tissues to the deep fascia. Care is taken to avoid the lateral cutaneous nerve of the forearm, which crosses the RA from lateral to medial near the distal extremity of the incision.
The deep fascia is then divided 3 mm medial to the edge of brachioradialis muscle so as to avoid the 3–5 branches of the RA that pass around the medial border of this muscle. They are more easily identified and divided after retraction of the muscle.
Deep to brachioradialis lies a well defined fascia surrounding RA and its satellite veins and is referred to as the `neurovascular fascia' (Fig. 1 ). Once this fascia is divided, the RA lies within loose areolar tissue and is very easily harvested (Fig. 2 ). This is the most important step in radial artery harvest. The deep fascia and neurovascular fascia fuse in the distal third of the forearm, beyond the tendon of brachioradialis, and should be divided together. There is also a fascia overlying the deep flexors of the forearm and this should not be divided since the RA lies anterior to this plane.
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The satellite veins should be grasped and not the RA itself. The ulnar artery is easily seen and the RA should be divided distal to this. A large muscular branch to brachioradialis may be preserved if the full length of RA is not required. The RA should be divided at the distal extremity of the incision. This is proximal to the wrist joint and so preserves the collateral supply around this joint. All blood is evacuated from the RA if heparin has not yet been administered to prevent clot formation in the conduit.
The fat and skin, but not the deep fascia is closed. The arm is bandaged immediately without a drain. It is secured by the side of the patient with drapes and the arm board removed. The operation continues without further preparation or draping.
Radial artery spasm
In our experience spasm of RA is uncommon and usually occurs in the setting of rough dissection. Excessive traction and the use of blunt rather than sharp dissection results in localized spasm. It is usually easily corrected by our routine use of topical and intraluminal papaverine (1 mg/ml with or without added blood). Rarely, is probing required.
No intraoperative, prophylactic systemic vasodilator is used. Indeed, approximately two thirds of our patients receive vasoconstrictors as a bolus or infusion in the perioperative period to elevate blood pressure. Storage of RA in cold solution for some time often results in apparent and diffuse narrowing but resolves within seconds of re-estabilishing pulsatile flow.
Conduit ischaemia
Conduit ischaemia is minimized when the left internal mammary artery (LIMA) and left RA are harvested simultaneously and the two joined as a Y graft immediately. When a significant delay is expected prior to reperfusing RA then we store the RA in a solution containing blood.
Functional arm assessment
A non-selected group of patients returned to a clinic at 3 and 12 months postoperatively. Sensation was tested using the Semmes Weinstein monofilaments minikit (North Coast Medical, Campbell, CA) and exert varying pressures [7]. Normal sensation was noted with the 2.83, reduced light touch 3.61 and loss of protective sensation with the 4.56 and 6.65 filaments. In clinical practice both normal and reduced light touch sensation is regarded as normal since the patient may be expected to complete all functional activities and their standard testing protocol was used [7]. Gross grip strength was measured using the Jamar dynamometer (Asimow Engineering, CA). Pinch strength was assessed using a pinchometer (B and L Engineering, Santa Fe Springs, CA). Protocols used were as for Mathiowetz [8]. The control arm was the non-operated arm with patients undergoing bilateral RA harvest being excluded. No preoperative assessment of strength was present for these patients. In addition assessment of the scar and activities of daily living were made.
Preoperative and postoperative index finger pulse oximetry, as well as Allen's test score for the same group of patients were recorded. The highest numeric value of the saturation observed was recorded.
Statistical methods
For analysis of unordered categorical data, the Fisher's exact test was used and for ordered categorical data, the exact Cochran–Armitage trend test [9]. For continuous data the unpaired t-test and for the paired sample tests of strength and pulse oximetry, the paired samples t-test was used.
All tests used the two sided P-value. Statistical significance was considered present if P0.05; or P'0.05 having been adjusted from the raw P-value by the Ryan–Holm stepdown procedure for the Bonferroni inequality [10]. This method controls for excessive familywise Type 1 error rate that results from testing multiple hypotheses [11][12].
SPSS 8.0 for Win95/NT (SPSS, Chicargo, IL) was used for Fisher's exact test, unpaired and paired samples t-test; and StatXact 3.1 for Win95/NT (Cytel Software, Cambridge, MA) was used for the exact Cochran–Armitage test.
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Results |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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A dramatic rise in use of RA occurred during 1996 (Fig. 3 ) following a year in which this conduit was used cautiously, mostly by one surgeon. Since 1997, RA has been used in more than 80% of patients. The main effect on practice has been to increase the TAR rate to approximately 80%. Since many patients receive more than four grafts, such a high TAR rate requires use of sequential and composite grafting techniques that make more efficient use of conduit. This has lead to a similar rapid rise in exclusively pedicled TAR (ie TAR with avoidance of any aortic anastomoses mostly by using composite grafting between LIMA and RA) and is currently approximately 40% of all patients receiving coronary artery bypass surgery (CABG) (Fig. 3).
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Gross and finger pinch strength testing was 4.8 and 5.1% less in the operated compared with the non operated arm respectively (Table 3). Ninety-seven percent of these patients had RA removed from the non dominant arm.
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Twenty percent reported scar tightness or hypersensitivity. Five percent reported some difficulty with normal daily activities but none experienced difficulty returning to work.
Preoperative and postoperative index finger pulse oximetry saturations were analyzed (Table 4). There was a small, consistent difference between the operated and non operated hand preoperatively but not postoperatively at 3 or 12 months. There was a consistent increase in saturations in both operated and non operated arms at 3 months compared to preoperative observations. Where patients had a `normal' (5 s) preoperative Allen's test the saturations of the operated hand were consistently higher at 3 months compared with preoperative observations, but not for patients with Allen's 6–10 s (Table 5).
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Incomplete data prevents accurate rates of RA wound infection or haematoma to be published. However, haematoma was present in approximately 1%. Minor infection was present in <1% with no cases of severe infection that required either reoperation or operative drainage.
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Discussion |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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They stated that the improved results related to more meticulous dissection technique, avoidance of metal probe dilation of RA and use of systemic prophylactic vasodilators commencing during the operation to prevent RA spasm. It is possible that these were not the only changes in the technique of CABG in almost 20 years and, therefore, may not entirely explain the improved results.
We harvest and manage the RA in the same manner as for the LIMA. The most important element in harvesting any conduit is to enter the correct anatomical plane. In the case of RA this is found deep to the fascia surrounding the artery and satellite veins (the `neurovascular fascia'). Since the RA is surrounded by loose areolar tissue in this plane, it is therefore easy to harvest this artery with minimal traction and by use of sharp rather than blunt dissection techniques. We agree that probing dilation of the RA is rarely indicated but we would advocate infusion of pharmacological vasodilators into the conduit lumen. We do not see advantage in vasodilating the entire body in order to achieve local RA dilation. Indeed, since most of our patients will undergo cardiopulmonary bypass at normothermia or mild hypothermia (32°C), our patients frequently experience a postoperative vasodilated state and require the administration of vasoconstrictors. We use norepinephrine to maintain a systolic blood pressure of 100 mmHg.
Many reports make reference to a high incidence of RA spasm even with use of systemic vasodilators [3][6][13]. Possible explanations may relate to a greater degree of hypothermia, or topical ice slush or that the RA may be left in solution for extended periods of time before grafting. We do find that the RA appears diffusely narrowed when cold but will become fully vasodilated within seconds of re-establishment of pulsatile flow.
RA was used cautiously during 1995. During the course of 1996 a revolution occurred where, by the end of the year, >80% of patients undergoing CABG had one or more RA harvested. There are several reasons for this.
The goal of TAR has always been appealing to surgeons since the concept of using saphenous vein (SVG) in an arterial circulation has always appeared less than ideal. Although there are histological differences between peripheral arteries, these are relatively minor when comparing arteries to vein. The first limitation has been the availability of sufficient arterial conduit. Bilateral internal mammary artery grafting has not been shown to be very greatly different from single internal mammary artery grafting [14][15][16][17]. Since most patients receive more than three grafts, both groups still received SVG and so the operations were, therefore, not very different.
The availability of RA, which was simple and safe to harvest, allowed most patients receiving three or less grafts to receive TAR. However, many patients still received four or more grafts and TAR was not routinely possible until the widespread introduction of sequential grafting and composite grafting techniques, which make more efficient use of conduit. These also allowed a reduction in the use of bilateral IMA in favour of RA and as a result would be expected to reduce sternal wound infection rates [18][19]. A mortality of approximately 20% may be expected with this complication [19].
The acceptance of RA was very rapid with TAR following a similar trend but more limited (Fig. 3). The continued rise of TAR to more than 80% was made possible by composite arterial reconstruction where arteries are joined to the LIMA as a `Y' graft and avoidance of proximal aortic anastomoses, presently in 40% of all CABG.
RA was not used frequently to the left anterior descending (LAD) territory since most patients receive a LIMA to LAD graft.
Mortality remained low even though there were dramatic changes to practice (Fig. 3Fig. 4). A 12-month period (1997) was selected after the use of RA stabilized and examined for evidence of preoperative selection bias. Only extent of preoperative myocardial infarction attained significance; although concomitant procedures were more common in those not receiving RA. This time frame examined 673 patients and so some caution in interpreting these results may still be prudent.
The operated hand was found to have a reduction in strength of approximately 5%. Patients recruited at this time however, had their non-dominant arm harvested in 97%. Crosby [20] found a difference of 6% for gross strength and 5% for pinch strength between the dominant and non-dominant hands of normal subjects. Consequently, we consider these findings to indicate normal postoperative arm and hand strength. This is not surprising since most of the muscles of the forearm are predominantly supplied directly or indirectly by the ulnar artery rather than the RA.
The low incidence of nerve damage would indicate that all but the lateral cutaneous nerve of forearm are easily avoided. It is important to consider that the only nerves that the RA may supply are cutaneous and are of lesser importance. The ulnar artery however, provides the main blood supply to the ulnar and median nerves with important sensory as well as motor functions.
Scar tenderness or hypersensitivity was common. Perhaps only an endoscopic harvest technique could eradicate this problem. It was the main reason for patients complaining of impairment to the conduct of activities of daily living using the RA harvest hand; and all of those treated with standard occupational therapy fully recovered.
Our preoperative test prior to all RA harvest was the Allen's test as described earlier. No patient had RA removed if the Allen's test was >10 s. In the patients reviewed for this study, pulse oximetry was recorded preoperatively and at postoperative review (Table 4). No differences were observed between the harvested and non-harvested arms at 3 or 12 month postoperative reviews. We did note differences, preoperatively, between arms destined to be harvested or not. The postoperative values for both harvested and non-harvested arms rose compared to preoperative values on the same arm, probably indicating that the overall SpO2 for the whole patient was improved by surgery. This was also true for harvested arms where the preoperative Allen's test was `normal' (5 s) but not where the test was `equivocal' (6–10 s). Nevertheless, all of the differences are extremely small and although statistically significant, probably not clinically relevant. Certainly no severe reduction in hand SpO2 was recorded. This would correlate with the extremely low incidence of clinically relevant hand ischaemia experienced at our institution for all patients undergoing RA harvest.
There are several limitations to this study. Our technique of harvest and policy on vasodilator/vasoconstrictor therapy have not been subject to prospective randomization. Although RA has been used since December 1994, it has only been used very widely for 2 years and no conclusion as to the late outcome of either the harvested arm and hand or indeed to the RA as a coronary graft can be made. In-hospital mortality may be multifactorial in nature and comprehensive multivariate analysis is required. Additional studies including angiography are currently in progress at our institution.
Peak strength testing is not a good measure of forearm or hand perfusion since short duration isovolemic muscular contraction utilises anaerobic rather than aerobic metabolism. Sustained contraction tests would be better but would need to be carefully selected so as to avoid the pressure within the relevant muscle mass exceeding blood pressure. Also the forearm musculature is predominantly supplied by the ulnar artery and is,therefore, a poor test for the RA. The data would suggest that forearm muscles were not damaged by RA harvest.
Pulse oximetry is a very simple and convenient method of assessment but has limited application in assessing subtle differences in perfusion. This is because the equipment can detect a pulsatile flow even when arterial pressures are very low [21][22].
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Conclusion |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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Acknowledgments |
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Footnotes |
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Appendix A. Conference discussion |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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Dr Royse: Well, the preoperative indications – firstly the Allen's test. If it is more than 10 s, we do not harvest the radial artery in our institution. In terms of its use as an arterial conduit – we have no difficulty with using it, provided in general we use the pedicled LIMA to the LAD. Clearly there is a small percentage of radial arteries which are diseased, either with calcification within the wall or more extensive bone-like calcification and, very rarely, atheromatous disease, where the disease within the radial artery conduit itself becomes a contraindication. In these patients the solution varies amongst the surgeons in the unit. My personal one would then be to harvest the second internal mammary artery and use that as the composite graft, but some of the other's may use saphenous vein.
Dr D. Javidi (Tehran, Iran): Have you had postoperative angiographic studies in the patients you have carried out this radial artery proceedure on, in this big series. How do you basically treat your radial arteries before anastomosing in these patients? How do you treat your radial arteries pharmacologically before anastomosing?
Dr Royse: Well, we treat the radial artery exactly the same as the LIMA. We use topical and intraluminal papaverine. We do not use a prophylactic systemic vasodilator in the perioperative period. Indeed, approximately two-thirds of our patients actually receive vasoconstrictors. As I have a policy of trying to maintain a minimum systolic arterial pressure of 100 mmHg during the entire perioperative period and also practice `warm heart surgery', we observe a low resistance state in more than half of the patients. Low blood pressure is treated either with a bolus of Metaraminol, for example, or as an infusion for many hours of noradrenaline. We don't seem to see the high incidence of spasm that is always referred to in papers and presentations. Indeed, spasm in our experience is primarily related to excessive traction and blunt rather than sharp dissection techniques during radial artery harvest. It is generally quite easily treated by topical and intraluminal papaverine, although rarely we do need to probe the vessel.
We have almost 100 radial artery angiograms. Given the nature of this talk, that has not been included, and I have submitted an abstract for the STS meeting. We have found a string sign in 13.4% of patients overall, most of whom were asymptomatic. We see a spectrum of degree of vasoconstriction depending on the degree of native coronary stenosis, and we are pursuing the investigation of the `autoregulation' of arterial conduit that may be possible in the face of competitive flow.
Dr R. Moses (Boston, MA): What is your rejection rate based on the preoperative Allen test? Do you have any comments about the effect of transradial catheterization that cardiologists are now doing on the utility of the radial artery graft?
Dr Royse: Firstly, to some extent the rejection rate varies a little between the surgeons. I don't recall ever rejecting a patient on the basis of an abnormal Allen's test where there has been no previous hand injury or surgery where I might otherwise have rejected them anyway. Our institutional rejection rate is less than 5%. I think that recent reports suggesting, perhaps, 20% of patients should be rejected is certainly not our experience. Regarding the radial artery as an angiographic port of entry. Yes, obviously we have some concern. However, a number of our patients, particularly those undergoing reoperation have already had cannulation of the radial artery by blood pressure monitoring devices, etc. We do sometimes see a little bit of scarring distally in those patients, but it has generally not been a problem. The radial artery is about 20–25% longer than the non-skeletonized LIMA and quite frequently the full length may not be required.
Dr N. Stolf (Sao Paulo, Brazil): Do you inject papaverine solution or do you just keep the radial artery in the solution? We have more or less the same number you have, and our preference now is to use the composite graft with anastomose on mammary artery. Do you have a study comparing patency with the composite graft end anastomosing on the aorta?
Dr Royse: Firstly, the papaverine. We use topical and intraluminal papaverine. Some use it with blood, some use it without. However, we would all use the same concentration, about 1 mg/ml. Regarding the angiographic assessment of both techniques. There are two concurrent studies, as well as, any symptomatic patients who are being angiogramed anyway, that we are tracking. Regarding the clinical outcome of both, we have some data. I can quote you the figures from last year, 1997, where total arterial revascularization as a group: the in-hospital mortality was 0.7%; and the composite group (the pedicled group, if you like) was 0%. I have not examined, specifically for this talk, the two techniques, but I am in the process of doing that analysis for a manuscript that I am preparing at present. Unfortunately there is still some missing data and we are having to take the records out before finally completing the analysis.
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References |
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TopAbstractIntroduction
Methods and materials
Results
Discussion
Conclusion
Appendix A. Conference...References |
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