Radial Artery Versus Saphenous Vein As
Conduits In Coronary Artery Surgery:
Comparison Of Intermediate To Long-Term
Outcomes
Rajdeep S. Bilkhu, Anne S. Ewing, Vipin Zamvar
Department of Cardiac Surgery, Royal Infirmary of Edinburgh
cite as: Bilkhu RS, Ewing AS & Zamvar V. Radial Artery Versus Saphenous Vein As Conduits In Coronary
Artery Surgery: Comparison Of Intermediate To Long-Term Outcomes. The Physician 2012 vol1;issue1:22-
26 DOI: 10.38192/1.1.2
Abstract
BACKGROUND AND AIMS
The radial artery has become an increasingly popular arterial conduit in coronary artery bypass graft
surgery (CABG), however little data exists with regard to comparison of quality of life in patients
undergoing CABG with radial artery grafts and those with conventional saphenous vein grafts. The aims
of this study were therefore to identify any difference in long term quality of life in surviving patients
between those undergoing CABG with radial artery grafts and those with saphenous vein grafts.
METHODS
Standardised questionnaires (SF-36 and Euroqol EQ5D) were sent to assess quality of life in 130 patients
who had undergone CABG with venous grafts (Group A) and 130 patients who had undergone CABG with
radial artery grafts (Group B). Information was also gathered to determine any angina recurrence
following CABG in the patients included in the study. In addition, information on any major adverse
cardiac events (MACE) occurring post-CABG was collected.
RESULTS
70 responses were received from Group A and 82 from Group B. The mean follow up time was 6 years in
both groups. On analysis there was no statistically significant difference between both groups with regard
to quality of life (based on SF-36 and EQ5D scores), angina recurrence or MACE.
CONCLUSION
Our study identified no additional benefit in using radial artery grafts over saphenous vein grafts with
regard to quality of life, MACE or angina recurrence in the medium term.
Introduction
The advantages of arterial endothelium have resulted in the use of arterial conduits in coronary artery
bypass graft surgery (CABG), and this has become an increasingly popular alternative to saphenous vein
grafts (SVGs). This is largely due to low rates of recurrent atherosclerosis in arterial grafts, which
consequently results in lower incidence of recurrence of symptoms of myocardial ischaemia.1, 2 The left
internal mammary artery
(LIM
) is considered the
“gold standard” conduit in myocardial
revascularisation due to excellent long term patency.1-3 The poor long term results seen with SVGs, and
promising results seen with LIMA has led to the search for additional arterial conduits for CABG.4 The
radial artery (RA) is being used more commonly as a conduit for CABG. Studies have demonstrated
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superior patency rates in patients receiving RA grafts over SVGs. 3,5 It is well known that vasoactive
substances produced by arterial endothelium are protective and so are likely to have a role in the
excellent patency rates of arterial conduits seen in those such as the RA.6, 7 Despite this, there is some
angiographic data in early post-operative patients suggesting poor RA graft patency. This may be related
to the spasmogenic nature of the radial artery.8 Indeed; it was noted soon after Carpentier et al first
proposed the use of radial arteries for CABG in 1973 that spasm and occlusion occurred in these grafts.9
This led to the RA being abandoned before being introduced again in 1992 by Acar et al.9, 10 The benefits
of the radial artery in the longer term should therefore be ascertained to determine its suitability as a
potential alternative to venous grafting͘ In particular, the benefits on patients’ quality of life should be
identified to help in determining the suitability of the radial artery as a conduit for CABG. We therefore
selected a sample of surviving patients in the period 2001- 2002 who underwent CABG and received RA
grafts. We analysed their perceived health related quality of life (QOL) and any major adverse cardiac
events (MACE) occurring post-CABG and compared this to data obtained from patients who had received
SVGs at CABG in the same period. Data was also gathered relating to angina recurrence and further
cardiac procedures performed after CABG such as percutaneous coronary intervention (PCI). Based on
available data, it was hypothesised that those receiving RA grafts would report a higher quality of life, less
angina, and fewer MACE than those receiving SVGs.
Methods
Ethical approval was obtained from the Lothian Research Ethics Committee. Between January 2001 and
December 2002,11,12 patients underwent primary isolated first time CABG at the Royal Infirmary of
Edinburgh. Of these patients 1073 had 3-vessel disease. Patients were divided into three groups
depending on the conduits used for surgery. Group A consisted of patients who received a LIMA graft and
one or two SVGs. Group B consisted of patients who received a LIMA graft, and a RA graft with or without
additional SVGs, as required. All other patients, who received only veins, bilateral mammary artery grafts,
or other conduits were put into group C and excluded from the study. Group A consisted of 591 patients,
and Group B consisted of 194 patients. Patients who died in hospital were excluded from both groups.
Data was obtained from the Registry Office to exclude patients who died after discharge from hospital.
Of the surviving patients, the first 130 in chronological order of operation date from each group were
selected for the purpose of this study. Patients in both groups were sent questionnaires to assess QOL.
Standardised questionnaires, the EuroQol EQ5D and the SF-36 Health Survey were used. 11, 12 To assess
for the presence of exertional chest pain, the shortened ROSE angina questionnaire was used.13, 14 In
addition, a separate questionnaire was written to collect data on patients’ current medication, M CE
occurring post-CABG and any strokes, angina recurrence, follow up percutaneous coronary intervention
(PCI) or CABG and any pain from the conduit harvest sites or from the sternal wound. It was assumed
those reporting higher health related QOL scores in the EQ5D and SF-36 questionnaires would be less
physically and mentally restricted by their ischaemic heart disease and would have had a good outcome
from their CABG. Similarly with angina recurrence and MACE, lower reported rates of these would suggest
a more positive outcome overall and a higher QOL. Patients were asked to complete and return the
questionnaires in the prepaid envelope provided. Those who did not reply were sent reminders after 3
weeks to maximise the number of responses. The replies received were then entered onto a spreadsheet
and quality of life scores calculated.
Results
STATISTICAL ANALYSIS
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Data collected from questionnaires was stored on a spreadsheet and analysed using SPSS v13.0 for
Windows.15 Continuous variables were expressed as the mean ± standard deviation and analysed using
the student’s t-test͘ Categorical variables were analysed using the chi square test or Fisher’s exact test,
as appropriate. A p value of <0.05 was considered statistically significant. 130 questionnaires were sent
to each group. In group A, 46 reminders were sent and a total of 70 responses were received. In group B,
58 reminders were sent, and a total of 82 responses were received. Patients who did not respond were
excluded from the study. Questionnaires were received from 152 patients. The calculated scores and
totals for the domains assessed in group A (n=70) and group B (n=82) were then compared. The patient
characteristics are shown in Table 1.
Results and comparison of the assessed domains is shown in Table 2.
MEAN FOLLOW-UP
The mean follow-up in Group A was 78 months, and in Group B, 72 months.
AGE and OPERATIVE RISK
Patients who received vein grafts, i.e. group A, were on average older than group B patients who received
radial artery grafts, as shown in Table 1.
MAJOR ADVERSE CARDIAC EVENTS (MACE) & STROKE
As shown in table 2, most patients in both groups were taking statin medication at the time of completing
the questionnaire (83% and 85% in group A and B respectively). With regard to MACE, 3 patients in each
group had suffered an MI (p=0.84) where as 2 people suffered a stroke in group A and 3 in group B
(p=0.79) (See Figure 1). No patients in either group underwent a further CABG operation.
PERCUTANEOUS CORONARY INTERVENTION (PCI)
12 (17.1%) in group A and 13 (15.8%) in group B had undergone PCI following their CABG operation (see
Figure 2). However, there was no statistical significant difference (p=0.8). PCI was performed at a mean
of 59 months after CABG in Group A, and 60 months in Group B.
ANGINA RECURRENCE and CHEST PAIN
In group A, a total of 8 patients (11.4%) reported recurrent angina where as 15 (18.3%) in group B had
experienced angina following CABG (p=0.23). ROSE scores showed similar numbers of patients in both
groups experienced exertional chest pain following CABG.13 (See Figures 3&4) 9 from group A and 13
from group B (p=0.18) complained of pain in the sternal wound. When reviewing comments made by
patients, it was noted that most who experienced this described discomfort or an itch as opposed to pain
per se. Some patients complained of reduced sensation on the left side of the chest, correlating with the
use of LIMA. A number of patients, particularly in group B, complained of itching and discomfort in the
conduit harvest sites.
QUALITY OF LIFE
Health related QOL was assessed by administration of Euroqol EQ5D and SF-36 Health Survey.11, 12 After
recoding, scores were calculated. The Euroqol EQ5D provided an overall score based on 5 separate health
related questions, whereas the SF-36 provided scores for a number of ‘health components’ based on the
questions answered, which were then collated to give a physical component summary (PCS) score and a
mental component summary (MCS) score. Group A patients had a mean EQ5D score of 0.7994 whereas
the mean for group B patients was 0.7522 (p=0.26). The mean SF-36 PCS score for group A was 41.6,
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whereas in group B a mean score of 43 was reported (p=0.54). MCS scores for both groups were similar;
52.6 and 54.1 for groups A and B respectively (p=0.36). Both groups scored consistently higher in the
mental component score. (See Figure 5). As part of the EuroQol questionnaire, patients were asked to
score their own health out of a total of 100 (the Euroqol Visual Analogue Scale or EQ-VAS). The mean
scores (detailed in Table 2 as Mean EQ-VAS Score) for groups A and B were, again, similar. Results showed
no statistically significant difference between group A and group B in relation to MACE, PCI procedures
performed after CABG, angina recurrence or QOL. A statistically significant difference was noted with
regard to patient age at the time of operation (p<0.01).
Discussion
Despite the increasingly popular use of the RA as a conduit for CABG, this study has shown no statistically
significant difference in the long term with regard to health related QOL, angina recurrence or major
adverse cardiac events between those undergoing CABG with SVGs and those receiving RA grafts. The
results obtained are contrary to what we believed, as it was anticipated those undergoing CABG with RA
grafts would report lower rates of angina recurrence, lower rates of MACE and a higher QOL. The results
are somewhat contradictory to the popular conception that RA grafts are superior to venous grafts.10,
18, 19 Promising data from Shah et al demonstrated patency rates of RA grafts to be as high as 96% after
5 years, in a sample of 209 post-CABG patients. Certainly, others have confirmed similar findings.20 This
has led to some considering the R a second choice conduit after the “gold standard” LIM
͘ 21,22 In our
study, all patients received left internal mammary artery (LIMA) to left anterior descending (LAD) grafts.
Based on strong evidence from numerous studies, the LIMA has been shown to have particularly high
patency rates.23-25 The LAD artery is the most important of the three coronary arteries, and grafting this
with the LIMA is responsible for the majority of the beneficial effect of CABG operation. In our study we
compared the RA versus SVG applied to the second and third most important coronary arteries. The
possible additional benefit of using RA grafts was studied and showed no difference in QOL or angina
recurrence. Although no specific studies have been conducted into QOL in this context, many have looked
at angiographic data in patients who had received RA grafts and compared this to those who have
undergone CABG with SVGs. Calafiore et al identified improvement in long term angiographic outcomes
in patients receiving RA grafts as compared to those receiving SVGs and showed that vein graft patency
was worse (91.7%) than radial graft patency (99%) suggesting a greater incidence of angina recurrence in
those receiving SVGs.5 Our study is unique in that the comparison of health related QOL in patients
receiving venous and arterial grafts is not well documented. Studies have looked at the effects on QOL
post CABG and have demonstrated supremacy against medical treatment of coronary artery disease.26
Despite this there has been no specific study assessing QOL and comparing this in those who have
undergone bypass with venous or arterial grafts. As mentioned, the QOL scores in both patient groups
were similar. The difference between SF-36 health scores of both groups was not statistically significant,
similarly with EQ-5D scores. Even with numerous studies demonstrating superiority of the RA over SVGs
in terms of patency rates, this it appears did not translate to a higher patient perceived health related
QOL in the RA group of our study. The similarity in results may be accounted for by use of LIMA, in that
the use of this “gold standard” conduit may have had such a dominant influence on outcome in the
studied patients due to its excellent long term patency, resulting in both groups experiencing similar
results and therefore reporting similar QOL and to some extent, angina recurrence. As well as this, the
length of follow up in the study may have had a role to play. In our study, the average follow up was 6
years and so an even longer follow up may have identified a more significant difference in QOL and in
angina recurrence. With regard to the age of the patients studied, the mean age of group B was
significantly less than that of group A. As patients in group A were older, it is likely that many of these
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patients suffer co-morbidities, such as musculoskeletal or respiratory disease and most likely this would
produce a lower QOL score. As patients in group B were younger, this would not seem to account for the
similarity in QOL scores observed as one would expect these to be higher than group A scores. This may
suggest those in group B are more limited from their cardiovascular disease. However, as the number of
those reporting angina recurrences and other MACE is similar, it would not seem appropriate to draw the
conclusion that quality of life is lower than what one would expect in this group.
A limitation of the study is the relatively small sample size and that despite showing a marginal difference
between both groups, this possible difference did not reach statistical significance to allow us to draw
fully valid conclusions. A further, larger follow up study would be a suitable means of assessing any
possible difference in QOL, angina recurrence and MACE. In addition, matching patients, particularly in
terms of age may help to provide a more accurate assessment of quality of life between both groups as
the impact of illness and disease is highly likely to have an influence on the quality of life of a patient at
different ages in life.
CONCLUSION
In summary, our results show that the use of the RA as a conduit for CABG does not confer any additional
benefit over SVGs in the intermediate-tolong term with regard to QOL, angina recurrence or MACE. ■
Acknowledgements
Funding for this study was received from the Royal Medical Society, Edinburgh.
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