Automatic postoperative monitoring of infrainguinal bypass procedures
J. Blebea, M. K. Ali, M. Love, R. Bodenham and B. Bacik
Division of Vascular Surgery, University of Cincinnati Medical Center, Ohio, USA.
OBJECTIVE: To evaluate the usefulness of a portable, computer-based,
oscillometric, noninvasive blood pressure monitor for the automatic
surveillance of postoperative infrainguinal bypasses. DESIGN: Prospective
unblinded study. SETTING: Regional tertiary care Veterans Affairs medical
center. PATIENTS: A total of 60 limbs were examined in 3 groups (n = 20 in
each group): normal, asymptomatic volunteers; older patients with
symptomatic peripheral vascular disease; and patients who had undergone
infrainguinal bypass procedures. INTERVENTIONS: Noninvasive blood pressure
monitor pressures, complete lower extremity arterial studies with Doppler
ankle-brachial index (ABI), segmental pressures, and pulse volume
recordings were performed in all groups. The patients who had undergone
surgery also had hourly noninvasive blood pressure measurements taken. MAIN
OUTCOME MEASURES: Ankle-brachial indices obtained with the noninvasive
blood pressure monitor were compared with simultaneous manual Doppler ABIs
and pulse volume recordings. RESULTS: There was a significant overall
correlation between the Doppler-derived ABIs and automatic oscillometric
values (r = 0.89, P < .001). Although there was a slight difference in
absolute values (+/-SEM) (0.90 +/- 0.03 vs 0.84 +/- 0.03, respectively), an
excellent correlation was found between the 2 methods in the clinically
relevant range of ABI values between 0.60 and 1.10. The oscillometric
method, however, overestimated the ABI when it was less than 0.60 by the
Doppler method (0.61 +/- 0.02 vs 0.44 +/- 0.03, P < .001) and
underestimated it when it was more than 1.10 (1.05 +/- 0.02 vs 1.16 +/-
0.01, P < .001). (All values given as +/-SEM.) Oscillometric
overestimation correlated with depressed pulse volume recording waveforms
(P < .001) or diminished pulse volume recording amplitudes of less than
10 mm (P < .001). CONCLUSION: The automatic oscillometric monitor
provides a useful, accurate, objective, and quantitative method for
postoperative bypass graft surveillance.