Predictive Value of Peak Systolic Velocity for the Development of Graft Limb Complications After Endovascular Aneurysm Repair

Abstract

To determine the role of peak systolic velocity (PSV) data provided by duplex ultrasound (DUS) surveillance in the prediction of endograft limb complications after endovascular aneurysm repair (EVAR). All 478 consecutive patients (425 men; mean age 75±7 years) who underwent infrarenal EVAR between 2004 and 2010 had DUS scans at 1.5, 3, 6, 9, 12, and 18 months and annually thereafter over a median follow-up of 43 months (range 1-92). In a retrospective study, the PSV recorded from the proximal and distal regions of each stent-graft limb was extracted from each postoperative DUS scan for each patient up to the penultimate scan before diagnosis of a limb complication (limb occlusion, symptomatic or hemodynamically significant kinking, or hemodynamically significant DUS-defined stenosis) requiring reintervention. The median (range) PSV readings from the proximal and distal regions of each stent-graft limb over the course of follow-up were compared between patients who developed a limb complication (n = 38) and those who did not (n = 440). Time-dependent Cox proportional hazards modeling was performed after risk adjustment; results are presented as the hazard ratio (HR) and 95% confidence interval (CI). In the proximal stent-graft limb segment, the median PSV was 106 cm/s (42-308) in patients without limb complications vs. 121 cm/s (50-281) in those with limb complications. Corresponding values in the distal segment of the endograft limb were 113 cm/s (35-400) vs. 129 cm/s (58-420). After risk adjustment, increased PSV over time within both the proximal and distal segments of the stent-graft limb was significantly associated with the risk of limb complications (proximal HR 1.015, 95% CI 1.003 to 1.028, p = 0.014; distal HR 1.010, 95% CI 1.001 to 1.020, p = 0.025). Increases in the peak systolic velocity in stent-graft limbs were associated with an increased risk of limb complication, though no predictive threshold could be identified from scans prior to the development of a complication. This observation requires external validation and further investigation to define its clinical utility.