The anchor point algorithm: A morphometric analysis of anatomic landmarks to guide placement of temporary aortic Rescue stent grafts for noncompressible torso hemorrhage.

BACKGROUND

Noncompressible hemorrhage remains a high-mortality injury, which requires rapid damage control within minutes to avoid exsanguination. Retrievable stent grafts offer perfusion preserving hemorrhage damage control, and yet algorithms for device selection and positioning are lacking for an anatomically diverse human population. We hypothesized that easily acquired external measurements could be used to rapidly triage patients to receive one of several presized stents and that these metrics may further predict a single target on the aorta by which to optimize both mesenteric perfusion and aortic hemorrhage control.

METHODS

Metrics were acquired from computed tomography imaging of 203 male and female patients aged 18 to 50 years. Algorithms for metric based triage and stent sizing were examined against the cohort for effectiveness. Linear regression was used to predict a single target on the aorta for alignment of a multitiered stent. Next, the relationship of the anchor point to the palpable xiphoid was determined.

RESULTS

Clavicle to pubis measurements correlated with aortic length and was used to triage patients to one of three stent grafts. Stents for each triage group were sized to achieve >75% coverage of aortic Zones 1 and 3 in most patients while preserving carotid and visceral perfusion. A metric/sex-based equation that predicts the location of the superior mesenteric artery relative to the palpable xiphoid was derived. By alignment of a single point on the stent with this target, known as the anchor point, the remainder of the stent can be rapidly deployed while minimizing coverage of critical branches. When applied back to the cohort, only 10.4% had potential serious branch coverage events predicted.

CONCLUSION

Simple anatomic metrics offer rapid triage in this study population to one of three presized stent grafts and predict the location of key vascular branches. Confirmatory human trials will be essential to demonstrate safety and effectiveness of this approach.

LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level IV.