Application of the Risk Analysis Index in Endovascular Aortic Aneurysm Repair Procedures
Wayne Tse, MD, Matthew George, MD, Luke Wolfe, MS, Michael F. Amendola, MD.
VA Medical Center/VCU Health System, Richmond, VA, USA.
BACKGROUND:
There are several risk calculators utilized in management of surgery patients. A formal screening process has been developed to identify frail patients considering elective surgery called the risk analysis index (RAI). This tool has been validated to discriminate frail patients from non-frail patients. Our group and others have utilized total psoas muscle area (TPA) as a predictor of late mortality in patients undergoing endovascular aortic aneurysm repair (EVAR). We sought to implement the RAI score retrospectively to predict post-operative mortalities after EVAR.
METHODS:
All patients who underwent elective EVAR at a single Veterans Affairs Medical Center from December 2010 to March 2016 were included. Patient characteristics and clinical data such as age, body mass index, comorbidities, AAA preoperative size, preoperative serum albumin, length of stay, post-operative complications (urinary, pulmonary, technical and other), date of last known follow up, date of death and RAI score were collected retrospectively. All CT images were analyzed in Phillips iSite PACS v 3.6 (Philips Healthcare, Andover, Mass) for left and right psoas muscles area measurements. All measures were taken on the axial CT slice immediately inferior to the fourth lumbar (L4) superior endplate using the standard PACS manual outline tool. TPA was calculated by adding the cross-sectional areas of the left and right psoas muscles. Fisher’s Exact** and two-tail t-test* were utilized as well as multi-variant logistical regression.
RESULTS:
A total of 119 entries had complete records for RAI scoring. Comparing the groups:
| Alive at End of Study n=90 | Post-Operative Death n=29 | p value | |
| Length of Stay (days ± SD) | 2.3 ± 1.7 | 4.8 ± 4.8 | 0.0002* |
| TPA (cm2 ± SD) | 26.2 ± 6.3 | 23.5 ± 6.3 | 0.0.002* |
| Age (years ± SD) | 69.0 ± 6.9 | 74.2 ± 7.3 | 0.0008* |
| RAI (score ± SD) | 9.8 ± 2.6 | 12.2 ± 9.2 | 0.003* |
| Post-Operative Complication (%) | 28.8% | 51.7% | 0.04** |
There was significant difference between the alive and mortality groups except chronic kidney disease (31.3% vs. 11.1%, p=0.01**) respectively.
CONCLUSIONS:
In our analysis, retrospective application of the RAI to patients undergoing EVAR found a significantly higher score in patients who were not alive at the end of the study period. Mean TPA was also significantly lower for the mortality group. These data should encourage utilization of the RAI as a screening tool to predict post-operative mortality and guide risk discussions for patients undergoing EVAR.
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