RESULTS
Recruitment
Trial recruitment was from December 2009 until October 2013. A total of
712 patients were assessed for eligibility. Of 195 patients who were
approached, 109 consented, and 97 were randomised into the trial.
Overall, 46 patients were allocated to receive conventional harvest, and
51 to receive pedicled harvest; 49 to receive low pressure, and 48 to
receive high pressure (Figure 1 ).
The primary analysis included 96 randomised patients, excluding one
patient who was withdrawn during surgery as no vein grafts were
harvested. Protocol deviations occurred in 37 grafts from 21 patients
(Table 1 , Appendix Table A1 ). In total, 17 patients
randomised to pedicled harvest received conventional harvest, 6 patients
randomised to low-pressure received high-pressure. Unblinding of
treatment allocation occurred for one patient randomised to the pedicled
harvest and high-pressure group.
A total of 20 of the 96 patients did not attend for the 12-month IVUS
and angiography assessment, 12 of whom returned at least one
questionnaire at 12 months. Seventeen patients formally withdrew from
the trial, 15 from 12-month IVUS and angiography assessment only and 2
from all follow-up (Figure 1 , Appendix Table A2) .
Baseline
data
The mean age of participants was 66.0 years (SD 8.9), and 87/96 (91%)
were male. By chance, patients randomised to pedicled harvest were
slightly older than those randomised to the conventional harvest group
(mean 67.3 years vs. 64.5 years), and the low-pressure group had
proportionally more males than the high-pressure group (96% vs. 85%).
From histology of veins after surgical preparation, the median wall
thickness was greater in the low-pressure (0.39 vs. 0.32mm) and pedicled
harvest (0.39 vs. 0.31mm) groups and the median lumen diameter was
smaller in these groups (pressure comparison 2.87 vs. 3.30mm; harvest
comparison 2.87 vs. 3.35mm) (Table 2, Appendix Table
A3 ).
Operative
details
The median duration of surgery was 3 hours and was similar across
groups. Overall, 28/96 (29%) procedures were performed on-pump. Study
participants received a total of 275 grafts (mean 2.9 grafts per
patient), of which 160 (58%) were vein grafts. The most common vein
graft sites were RCA-PDA (n=50, 31%), Diag (n=21, 13%), OM1 (n=39,
24%) and OM2 (n=19, 12%), while the majority of arterial grafts were
LAD (n=90, 80%). Most vein graft conduits were judged good quality
(n=90, 56%), with a higher proportion of good quality conduits in the
conventional harvest group compared to the pedicled harvest group (61%
vs. 52%). Most vein grafts were taken from the left leg long saphenous
vein (n=132, 83%, Table 3, Appendix Tables A4 and A5 ).
Primary Outcomes at 12
months