Computed tomography correlation of skeletal landmarks and vascular anatomy in civilian adult trauma patients: Implications for resuscitative endovascular balloon occlusion of the aorta

Age affects vascular morphology and predictiveness of anatomical landmarks for aortic zones in trauma patients: implications for resuscitative endovascular balloon occlusion of the aorta

PURPOSE

Understanding the vascular morphology is fundamental for resuscitative endovascular balloon occlusion of the aorta. This study aimed to evaluate the effect of aging on length and diameter of aorta and iliac arteries in trauma patients, and to investigate the predictiveness of anatomical landmarks for aortic zones.

METHODS

A total of 235 patients in a regional trauma center registry from September 1, 2018, to January 3, 2024, participated in the study. Reconstruction of computed tomography was applied to the torso area. The marginal diameter and length of aorta and iliac arteries were measured. Anatomical landmark distances and aortic marginal lengths were compared.

RESULTS

The length and diameter of aorta and iliac arteries increased with age, and a tortuous and enlarged morphology was observed in older patients. There was a good regression between age and diameter of the aorta. Neither the jugular notch, the xiphisternal joint, nor the umbilicus could reliably represent specific margins of aortic zones. The distance between the mid-sternum and femoral artery (427 ± 25 to 442 ± 25 mm for right, and 425 ± 28 to 440 ± 26 mm for left) was predictive for zone 1 in all groups. The distance between the lower one-third junction of the xiphisternum to the umbilicus and femoral artery (232 ± 19 to 240 ± 17 mm for right, and 229 ± 20 to 237 ± 19 mm for left) was predictive for zone 3 aorta.

CONCLUSION

Aging increases the length and diameter of aorta and iliac arteries, with a tortuous and enlarged morphology in geriatric populations. The mid-sternum and the lower one-third junction of the xiphisternum to the umbilicus were predictive landmarks for zone 1 and zone 3, respectively.

Comparison of aortic zones for endovascular bleeding control: age and sex differences

PURPOSE

To gain insight into anatomical variations between sexes and different age groups in intraluminal distances and anatomical landmarks for correct insertion of resuscitative endovascular balloon occlusion of the aorta (REBOA) without fluoroscopic confirmation.

MATERIALS

All non-trauma patients receiving a computed tomography angiography (CT-A) scan of the aorta, iliac bifurcation and common femoral arteries from 2017 to 2019 were eligible for inclusion.

METHODS

Central luminal line distances from the common femoral artery (CFA) to the aortic occlusion zones were measured and diameters of mid zone I, II and III were registered. Anatomical landmarks and correlations were assessed. A simulated REBOA placement was performed using the Joint Trauma System Clinical Practice Guideline (JTSCPG).

RESULTS

In total, 250 patients were included. Central luminal line (CLL) measurements from mid CFA to aortic bifurcation (p = 0.000), CLL measurements from CFA to mid zone I, II and III (p = 0.000) and zone I length (p = 0.000) showed longer lengths in men. The length of zone I and III (p = 0.000), CLL distance measurements from the right CFA to mid zone I (p = 0.000) and II (p = 0.013) and aortic diameters measured at mid zone I, II and III increased in higher age groups (p = 0.000). Using the JTSCPG guideline, successful deployment occurred in 95/250 (38.0%) in zone III and 199/250 (79.6%) in zone I. Correlation between mid-sternum and zone I is 100%. Small volume aortic occlusion balloons (AOB) have poor occlusion rates in zone I (0-2.8%) and III (4.4-34.4%).

CONCLUSIONS

Men and older age groups have longer CLL distances to zone I and III and introduction depths of AOB must be adjusted. The risk of not landing in zone III with standard introduction depths is high and balloon position for zone III REBOA is preferably confirmed using fluoroscopy. Mid-sternum can be used as a landmark in all patient groups for zone I. In older patients, balloon catheters with larger inflation volumes must be considered for aortic occlusion.

Developing a morphomics framework to optimize implant site-specific design parameters for islet macroencapsulation devices

Delivering a clinically impactful cell number is a major design challenge for cell macroencapsulation devices for Type 1 diabetes. It is important to understand the transplant site anatomy to design a device that is practical and that can achieve a sufficient cell dose. We identify the posterior rectus sheath plane as a potential implant site as it is easily accessible, can facilitate longitudinal monitoring of transplants, and can provide nutritive support for cell survival. We have investigated this space using morphomics across a representative patient cohort (642 participants) and have analysed the data in terms of gender, age and BMI. We used a shape optimization process to maximize the volume and identified that elliptical devices achieve a clinically impactful cell dose while meeting device manufacture and delivery requirements. This morphomics framework has the potential to significantly influence the design of future macroencapsulation devices to better suit the needs of patients.

A new method using surface landmarks to locate resuscitative endovascular balloon occlusion of the aorta based on a retrospective CTA study

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) can timely prevent the wounded from fatal hemorrhage. However, blind insertion of REBOA in field or emergency room may result in catheter malposition and serious complications. We aim to develop a new method based on surface landmarks to guide the accurate placement of REBOA in zone III of aorta without fluoroscopy.

METHODS

A retrospective study was conducted in a university hospital, including 57 subjects who underwent computed tomography angiography (CTA) from April to December in 2019. External distances and intravascular lengths were measured by three-dimensional reconstruction of CT images, including the distances from the insertion site of femoral artery to the xiphoid process (FA-Xi), the midpoint between the xiphoid process and the umbilicus (FA-mXU), the umbilicus (FA-Ui), the midpoint of the zone III of aorta (FA-mZIII), the lowest renal artery (FA-LRA), and aortic bifurcation (FA-AB). The distal and proximal ideal margin and predicted accuracy were calculated by curvature plane reconstruction. The predicted probability of balloon positioning in zone III by different methods was compared.

RESULTS

The mean age of all patients was 60 years (SD = 9.4). The average length of zone III of aorta was 9.4 cm (SD = 1.0), and the length of FA-mZIII on the right and left sides were 24.4 cm (SD = 2.1), 23.8 cm (SD = 2.1), respectively. FA-Xi was longer than FA-LRA, and FA-Ui was shorter than FA-AB (paired two-tailed test, p < 0.001). Using three methods including the optimal quartering distances, the optimal distances below the xiphoid and above the umbilicus to predict the length of REBOA catheter positioning in zone III showed no statistically significant difference. The predicted accuracy of catheter positioning in zone III on the left and right sides guided by FA-mXU were 84.2% and 86%.

CONCLUSIONS

The midpoint between the xiphoid process and the umbilicus may be a new surface landmark for people of normal weight to guide rapid positioning REBOA in zone III of aorta without fluoroscopy.

Imaging Anatomy and Surface Localization of External Control Device-Targeted Arteries for Noncompressible Torso Hemorrhage

BACKGROUND

External hemorrhage control devices (EHCDs) are effective in reducing the death risk of noncompressible torso hemorrhage (NCTH), but the pressurized area is too large to prevent serious organ damage. This study aims to establish the surface localization strategy of EHCDs based on the anatomical features of NCTH-related arteries through CT images to facilitate the optimal design and application of EHCDs.

METHODS

Two hundred patients who underwent abdominal CT were enrolled. Anatomical parameters such as the length of the common iliac artery (CIA), the external iliac artery (EIA), and the common femoral artery were measured; positional relationships among the EHCD-targeted arteries, umbilicus, anterior superior iliac spine (ASIS), and pubic tubercle (PT) were determined. The accuracy of surface localization was verified by the 3D-printed mannequins of 20 real patients.

RESULTS

Aortic bifurcation (AB) was 7.5 ± 8.6 mm to the left of the umbilicus. The left CIA (left: 46.6 ± 16.0 mm vs. right: 43.3 ± 15.5 mm, P = .038) and the right EIA (left: 102.6 ± 16.3 mm vs. right: 111.5 ± 18.8 mm, P < .001) were longer than their counterparts, respectively. The vertical distance between the CIA terminus and the ipsilateral AB-ASIS line was 19.6 ± 8.2 mm, and the left and right perpendicular intersections were located at the upper one-third and one-fourth of the AB-ASIS line, respectively. The length ratio of EIA-ASIS to ASIS-PT was 0.6:1. The predicted point and its actual subpoint were significantly correlated (P ≤ .002), and the vertical distance between the two points was ≤5.5 mm.

CONCLUSION

The arterial localization strategy established via anatomical investigation was consistent with the actual situation. The data are necessary for improving EHCD design, precise hemostasis, and EHCD-related collateral injuries.Trial registration: Ratification no. 2019092. Registered November 4, 2020-retrospectively registered, www.chictr.org.cn.

Size matters: first-in-human study of a novel 4 French REBOA device

Background

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technique used for non-compressible torso hemorrhage. However, its current use continues to be limited and there is a need for a simple, fast, and low profile REBOA device. Our objective was to evaluate the feasibility of a novel 4 French REBOA device called the COBRA-OS (Control of Bleeding, Resuscitation, Arterial Occlusion System).

Methods

This study is the first-in-human feasibility trial of the COBRA-OS. Due to the difficulty of trialing the device in the trauma setting, we performed a feasibility study using organ donors (due to the potential usefulness of the COBRA-OS for normothermic regional perfusion) after neurological determination of death (NDD) prior to organ retrieval. Bilateral 4 French introducer sheaths were placed in both femoral arteries and the COBRA-OS was advanced up the right side and deployed in the thoracic aorta (Zone 1). Once aortic occlusion was confirmed via the left-sided arterial line, the device was deflated, moved to the infrarenal aorta (Zone 3), and redeployed.

Results

A total of 7 NDD organ donors were entered into the study, 71% men, with a mean age 46.6 years (range 26 to 64). The COBRA-OS was able to occlude the aorta in Zones 1 and 3 in all patients. The mean time of placing a 4 French sheath was 47.7 seconds (n=13, range 28 to 66 seconds). The mean time from skin to Zone 1 aortic occlusion was 70.1 seconds (range 58 to 105 seconds); mean balloon volumes were 15 mL for Zone 1 (range 13 to 20 mL) and 9 mL for Zone 3 (range 6 to 15 mL); there were no complications and visual inspection of the aorta in all patients revealed no injury.

Discussion

The COBRA-OS is a novel 4 French REBOA device that has demonstrated fast and safe aortic occlusion in this first-in-human feasibility study.

Level of evidence

Level V, therapeutic.

Standardized distances for placement of REBOA in patients with aortic stenosis

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique where a balloon is advanced through the common femoral artery and temporarily inflated for treatment of cardiac arrest or non-compressible haemorrhage. The aim of this study was to measure intravascular distances relevant for correct placement of the REBOA catheter using computer tomographic (CT) scans. In a series of CT scans of the aorta from 100 patients diagnosed with severe aortic stenosis planned for transcatheter aortic valve implantation, we measured the intravascular distance from the insertion site in the common femoral artery to two potential zones for placement of the REBOA catheter; between the left subclavian artery and the celiac trunk (Zone 1), as well as between the aortic bifurcation and the distal take-off of the renal arteries (Zone 3). The mean (± SD) intravascular distance from the femoral artery to intra-aortic Zone 1 was 36 (± 2.5) cm for the lower border and 60 (± 4.1) cm for the upper border, respectively. For intra-aortic Zone 3, the mean (± SD) intravascular distance was 21 (± 2.1) cm to the lower border and 31 (± 2.3) cm to the upper border. Calculated potentially safe intervals for placement of the REBOA in Zone 1 was with 99.7% likelihood between 43 and 48 cm. No similar potentially safe interval could be calculated for Zone 3. According to this cohort study of patients with severe aortic stenosis, the balloon of the REBOA catheter should travel intraarterially between 43 (lower limit) and 48 cm (upper limit) from the site of insertion into the common femoral artery, which would lead to correct placement in intra-aortic Zone 1 in 99.7% of cases. In contrast, no potential safety interval could be similarly defined for insertion in Zone 3.

Placement accuracy of resuscitative endovascular occlusion balloon into the target zone with external measurement

Background

Resuscitative endovascular balloon occlusion of the aorta (REBOA) should be safely placed at zone 1 or 3, depending on the location of the hemorrhage. Ideally, REBOA placement should be confirmed via fluoroscopy, but it is not commonly available for trauma bays. This study aimed to evaluate the accuracy of REBOA placement using the external measurement method in a Japanese trauma center.

Methods

A retrospective review identified all trauma patients who underwent REBOA and were admitted to our trauma center from 2008 to 2018. Patient characteristics, REBOA placement accuracy, and complications according to target zones 1 and 3 were reviewed.

Results

During the study period, 38 patients met our inclusion criteria. The in-hospital mortality rate was 57.9%. REBOA was mainly used for bleeding from the abdominal (44.7%) and pelvic (36.8%) regions. Of these, 30 patients (78.9%) underwent REBOA for target zone 1, and 8 patients (21.1%) underwent REBOA for target zone 3. The proportion of abdominal bleeding source in the target zone 1 group was greater than that in the target zone 3 group (56.7% vs. 0%). Overall, the proportion of REBOA placement was 76.3% in zone 1, 21.1% in zone 2, and 2.6% in zone 3. The total REBOA placement accuracy was 71.1%. At each target zone, the REBOA placement accuracy for target zone 3 was significantly lower than that for target zone 1 (12.5% vs. 86.7%, p<0.001). No significant associations between non-target zone placement and patient characteristics, complications, or mortality were found.

Conclusions

The REBOA placement accuracy for target zone 3 was low, and zone 2 placement accounted for 21.1% of the total, but no complications and mortalities related to non-target zone placement occurred. Further external validation study is warranted.

Level of evidence

Level IV.