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Interact CardioVasc Thorac Surg 2008;7:797-800. doi:10.1510/icvts.2007.172569 © 2008 European Association of Cardio-Thoracic Surgery
Non-harvestable radial artery. A bilateral problem?
a Heart Center, Tampere University Hospital, P Box 2000, 33521 Tampere, Finland Received 28 November 2007; received in revised form 9 April 2008; accepted 10 April 2008
*Corresponding author. Tel.: +358 3 31165039; fax: +358 3 31165045.
Since radial artery is preferably harvested from a non-dominant hand, our aim was to study whether there are contraindications for radial artery harvest in the dominant hand if the radial artery of the other hand is not suitable for harvesting. Thirty-three patients scheduled to coronary artery bypass grafting with contraindication for radial artery harvest in the non-dominant hand underwent Allen test, upper arm Doppler ultrasonography and digital pletysmography. In ultrasonography, both anatomical and circulatory measurements were performed. Both hands were then compared to each other. Furthermore, twelve control patients without contraindication for radial artery harvest in the non-dominant hand were examined. All 33 patients had contraindication for radial artery harvest in the non-dominant hand. Twenty-four (73%) had contraindication in the dominant hand as well. In terms of morphology, there was no statistically significant difference between the hands but circulatory parameters as a group suggested contraindication. Among controls, four patients (33%) had contraindication in the dominant hand. In the case of a non-harvestable radial artery in a hand there is clearly an increased risk for contraindication for radial artery harvest also in the other hand.
Key Words: Radial artery; Coronary artery bypass grafting; Ultrasonography
Radial artery is widely utilized as a conduit for coronary artery bypass grafting nowadays. It offers many advantages. It is easy to harvest and handle and its patency rates seem superior to venous grafts [1]. When planning total arterial revascularisation it is considered as a conduit of third choice. Optimal preoperative assessment has been studied in detail earlier [2]. Following guidelines drawn by these studies selection of suitable grafts can be done in a safe manner. Traditionally the non-dominant hand is the first choice for harvest in order to avoid neurological and ischemic complications in the dominant hand. Unfortunately there is contraindication for the harvest of radial artery in 10–27.7% of the cases [3, 4]. The evaluation of the dominant arm becomes necessary, when there are contradictory findings preventing the harvest of radial artery in the non-dominant arm or there is need for two radial artery grafts. There are several functional reasons preventing the harvest of the radial artery. The artery itself may be too small or it may have intimal or medial calcifications. The circulation of the hand may be dependent on radial artery due to insufficient anastomotic connections between the radial artery and ulnar artery or the ulnar artery may be hypoplastic or absent. The aim of this study is to find out how the status of the non-dominant arm correlates with the dominant arm and whether the issues leading to non-harvestable radial artery are limited only to the one side of the patient.
Between October 2000 and April 2005, 145 patients who were planned for coronary artery bypass grafting (CABG), with a possible use of the radial artery as a conduit, were examined with Doppler ultrasonography and digital pletysmography. Patients older than 60 years and emergency cases were excluded. Forty patients had a contraindication for radial artery harvest in non-dominant arm. Thirty-three patients out of 40 had their dominant arm examined as well. These 33 patients were included in this study as a study group. Seven patients were left unexamined due to practical reasons such as lack of laboratory time. The majority of patients were right-handed (30 vs. 3) males (29 vs. 4). Mean age was 53.2 years (S.D. 5.0). Additionally, there were 12 patients with both arms examined without contraindication for radial artery harvest in the non-dominant hand. These 12 patients were included as a control group. Patient demographics and risk factors are summarised in Table 1.
Morphological findings were assessed with biplane ultrasonography. Inner diameter of both major arteries was measured both distally and proximally. Sclerosis of the media and intimal calcifications were observed as well as anatomical anomalies. Circulatory measurements included peak systolic velocity (PSV) and end diastolic velocity (ESV) on both radial and ulnar artery. PSV was recorded again on the ulnar artery while the radial artery was occluded by compression. Furthermore, the distal part of the radial artery was controlled for reverse flow while the proximal part was compressed. Emission frequency of the transducer was between 5 and 10 MHz, based on best visibility (Aloka, Pro Sound 5500). Digital blood pressures were measured with pletysmography (Finapress) both at rest and during radial artery compression. Contraindications for radial artery harvest based on these examinations are presented in Table 2.
As each non-dominant hand had its own matched control, namely the dominant hand, the statistical significance was analysed by using McNemars test for paired proportions. Comparisons between study group and control group were analysed with Student's t-test. Analyses were performed using SPSS 15.0 software.
All patients in the study group had a contraindication for radial artery harvest in their non-dominant arm. Twelve patients had circulatory parameters that prevented the radial artery harvest; in 11 patients the radial artery wall morphology suggested sclerosis or small diameter and 10 patients had both circulatory and morphological contraindications in their non-dominant arm. Proximal inner diameter of the radial artery in the non-dominant arm was 3.02±0.90 mm (range 1.2–5.3) and distal inner diameter was 2.4±0.65 mm (range 0.9–3.4). Corresponding figures for the dominant arm were 2.97±0.69 mm (range 0.9–3.9) and 2.39±0.60 mm (range 0.9–3.8). The radial artery was smaller than 2 mm in seven patients on the non-dominant arm and in six patients on the dominant arm. Intimal or medial calcifications were present in 13 patients' non-dominant radial artery whereas they were present in 11 patients' dominant arm. Two patients had an anatomical anomaly in the non-dominant arm. The other patient had a high brachial bifurcation level, only 3–4 cm distal to axillary artery and the other patient had a hypoplastic ulnar artery. There was only one anomaly on the dominant arm with a high level of brachial bifurcation. Seventeen patients failed to present reverse flow in the non-dominant distal radial artery during radial artery compression. In the dominant side there were 10 cases of absent reverse flow. In general, the ulnar arteries responded well to radial artery compression. Mean increase in ulnar PSV was 79.7±50.8% in the non-dominant side and 62.1±48.9% in dominant side. Less than 20% increase in ulnar PSV was seen in two non-dominant arms and in three dominant arms. Pletysmographic examination identified 23 patients with contraindication for radial artery harvest in the non-dominant arm and 16 patients with corresponding situation in the dominant arm. Proximal inner diameter of the radial artery in the non-dominant arm among control group was 2.92±0.52 mm (range 2.3–3.7) and distal inner diameter was 2.58±0.51 mm (range 2–3.4). Corresponding figures for the dominant arm among controls were 2.85±0.57 mm (range 2.1–3.8) and 2.44±0.39 mm (range 2–2.9). Three patients in the control group had sclerotic changes in the wall of the radial artery in the dominant hand. Two patients had significant drop in blood pressure in pletysmography during radial artery compression. There was no statistically significant difference in vessel size between the groups. Altogether 24 patients (73%) in the study group had a contraindication for radial artery harvest in their dominant arm. Statistical analysis revealed that there were no significant differences in morphological contraindications. Amongst circulatory contraindication there was dispersion and combining the contraindications there was statistical significance. Results of statistical analysis between the non-dominant and dominant hand among the study group are summarized in Table 3. In the control group there were four patients (33%) with contraindication for radial artery harvest in the dominant hand. Risk of having a non-harvestable radial artery in the dominant hand is doubled when there is a contraindication for radial artery harvest in the non-dominant hand. Risk ratio was calculated to 2.18 (95% confidence interval 1.14–4.14).
Cardiac surgeons are frequently faced with a problem of positive (i.e. abnormal) Allen test in the non-dominant arm of a patient whose radial artery is planned for harvest. In many cases further examinations with Doppler ultrasound and pletysmography reveal a harvestable graft with appropriate dimensions and sufficient compensatory flow in ulnar artery despite the positive Allen test. Some diseases, like diabetes or atherosclerosis, affect the wall of the vessel and thus compromise the graft. These patients can have negative (i.e. normal) Allen test but non-harvestable radial artery nonetheless. Therefore, in cases where the Allen test is positive (i.e. abnormal) or there is suspicion of vessel wall pathology, Doppler ultrasound and digital pletysmography performed preoperatively is a good screening method which decreases unnecessary explorations of the radial artery during the operation. To our knowledge, there are only few studies investigating the intra-individual variation of radial arteries. Abu-Omar et al. [5] performed the Allen test for 287 consecutive patients and found 43 patients with positive (i.e. abnormal) Allen test. These patients underwent Doppler ultrasonography. Out of 43, five had abnormal findings in Doppler ultrasonography and went for further scanning of the contralateral arm. Two patients had contraindications for harvest of the radial artery on both arms. This study was confined only to morphological scanning. No data on circulatory parameters were reported. Dogan et al. [6] have reported their results on the assessment of anatomy of radial artery with computed tomography angiography. Sixteen patients scheduled for CABG were examined and both arms were scanned in all patients. Six patients had contraindications for radial artery harvest, three had calcification on their radial artery and another three had anatomic anomalies. Both arms were scanned but it is not reported which of the arms had contraindications. Doscher and colleagues [7] studied 200 arms on 100 patients with Doppler ultrasound. Dimensions and flow of the major arteries were measured. They found that hand dominance had no significance in determining the vessel size or flow. There was significant difference between gender both in size and flow. Morphological contraindications such as small diameter of the radial artery, intimal or medial calcification or anatomic anomaly are dependent either on patient's anatomy or certain pathologic condition. Size of the artery is related to the body size and is therefore fairly symmetric. Anomalies vary but their number is too low in our material to draw conclusions. Intimal or medial calcifications reflect a systemic disease affecting the wall of the vessel. Both radial arteries are equally exposed to such disease. Circulatory requirements for radial artery harvest are adequate collaterals between the radial and ulnar artery and sufficient response in ulnar artery flow to meet the increased demand after harvest. Digital blood pressure and reverse flow in distal radial artery during radial artery compression reflect the collateral flow. Collaterals between the two major vessels of the arm are formed by four arches, two in the carpal area and two in the palmar area [8]. There is considerable variation in these connections and partly this variation can be intraindividual. Fulfilment of the second requirement is expressed in increased ulnar PSV. These two requirements are somewhat intertwined: without adequate collaterals the ulnar bed remains unchanged and there will be no increased demand. Earlier studies have shown that, after careful evaluation, 10–27.7% of the cases have non-harvestable radial arteries. In this study, we found that if the radial artery is, for some reason, non-harvestable in the non-dominant arm, risk that it is non-harvestable in the dominant arm is at least threefold. We anticipated that the morphological contraindications would be better correlated than the circulatory contraindications. If there is morphological contraindication for harvest of the radial artery in the non-dominant arm it is probable that that the condition is symmetrical and there is contraindication on the dominant arm as well. However, if the contraindication is circulatory there is the possibility that collateral circulation is different from side to side and the radial artery may well be harvestable on the dominant side. We conclude that in the case of non-harvestable radial artery in the non-dominant hand there is clearly an increased risk for contraindication for radial artery harvest in the dominant hand. Analysis of single variables does not reveal a feasible landmark for the decision making whether other radial is available or not.
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Abstract
1. Introduction
