Hemodynamic Consequences of Internal Iliac Artery Occlusion Following Endovascular Abdominal Aortic Aneurysm Repair Assessed by Near-Infrared Spectroscopy

Abstract

The purpose was to evaluate endovascular aortic repair (EVAR) patients with known gluteal claudication using near infrared spectroscopy (NIRS), and secondly to assess the hemodynamic consequences of occluding one internal iliac artery (IIA) during EVAR.EVAR interventions with occlusion of one IIA were examined. Gluteal claudicants were recruited from the outpatient clinic at their annual EVAR control (Group A; n=7) and a second cohort was collected consecutively and prospectively before and after the intervention (Group B; n=10). A treadmill test (12% incline, 2.4 km/h) with NIRS (INVOS-5100) sensors applied bilaterally on the gluteal regions was performed. NIRS was used to asses muscle oxygenation. NIRS data was divided into baseline, exercise and recovery values. Recovery times and absolute NIRS values (oxygenation) from the two gluteal sides were compared.Mean recovery times (group A) of the occluded and patent sides were 512 sec and 137 sec [0-643] (p=0.046) respectively. Using 240 seconds (suggested by literature) as cut-off the sensitivity and specificity were both 71% for finding the occluded IIA. Group B revealed similar oxygenation level of the two gluteal regions pre EVAR. Post EVAR an overall absolute reduction of the oxygenation were noted and a significant difference in the recovery values of the two gluteal sides (p<0.05).In this explorative study NIRS does show relevant changes of the oxygenation on the gluteal region following occlusion of an IIA in groups of patients. But given the lack of statistical power the efficacy of diagnostic use in individual patients has yet to be proven.