Should all in situ saphenous vein bypasses undergo permanent duplex surveillance?
C. R. Mohan, J. J. Hoballah, M. T. Schueppert, W. J. Sharp, T. F. Kresowik, E. V. Miller and J. D. Corson
Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, USA.
OBJECTIVE: To evaluate the need for color duplex surveillance (CDS) for
pure in situ bypasses beyond 6 months. DESIGN: We reviewed our in situ
surveillance data from August 1987 to April 1994. Lower-extremity
revascularization was performed using 245 pure in situ greater saphenous
vein bypasses in 219 patients. The CDS of the entire bypass and inflow and
outflow arteries was done prior to discharge, at 1 month, every 3 months in
the first year, every 6 months in the second year, and annually thereafter.
A peak systolic velocity of less than 45 cm/s throughout the bypass or a
velocity ratio of greater than 3 (peak systolic velocity at the stenosis
divided by peak systolic velocity at an adjacent normal bypass segment)
were defined as abnormal during the review of this patient subset. The
outcomes were analyzed. Patency and limb salvage rates were calculated by
life-table analysis. PATIENTS: The mean age of this population (120 men and
99 women) was 67 years (range, 32 to 97 years). We analyzed all bypasses
that were subjected to CDS for 6 months or more and identified 171 such
bypasses. These bypasses were followed up for a mean duration of 30 months
(range, 6 to 82 months). RESULTS: The primary and secondary patency and
limb salvage rates at 5 years were 60.4%, 89%, and 92.1%, respectively (SE,
< 10%). During the first 6 months of surveillance, 54 bypasses had
abnormal CDS findings, and 117 had normal CDS findings. Arteriography was
performed on 42 of these bypasses with abnormal CDS findings, and 37 had
significant findings requiring direct surgical or endovascular
intervention. Only two of 117 bypasses that had normal CDS findings for up
to 6 months had to be revised later, compared with 43 of the 54 bypasses
with abnormal CDS findings prior to 6 months, which were occluded or were
revised (significantly different by chi 2 test [P < .001]). CONCLUSIONS:
Vigorous CDS of pure in situ bypasses for up to 6 months is useful to
detect bypass-threatening lesions. Continued CDS of a normal in situ bypass
after 6 months may not be justifiable, as the incidence of lesions
requiring later revision is minimal.
