External validation of a nomogram predicting risk of bleeding control interventions after high-grade renal trauma: The Multi-institutional Genito-Urinary Trauma Study

External validation of the MiGUTS nomogram for the prediction of bleeding control intervention after renal trauma

INTRODUCTION

The American Association for the Surgery of Trauma (AAST) renal trauma grading leads to a variable management of patients with high-grade renal injuries. For a better prediction of the risk for bleeding interventions, Keihani et al. introduced the multi-institutional genito-urinary trauma study (MiGUTS) renal trauma nomogram in 2019. The aim of this study was to conduct an external validation and generalization for all kidney trauma cases of the nomogram with a European cohort of a Swiss level 1 trauma center.

METHODS

We collected data from the clinical information system of the Kantonsspital Graubünden, Chur, Switzerland. All patients ≥ 18 years of age from 01.01.2008 to 01.12.2020 with a renal trauma who underwent computed tomography imaging of the abdomen were included. The descriptive analysis was performed by a t-test/Wilcoxon signed-rank test and a Chi-square test. The predictions of the nomogram were analysed by the Pearson correlation coefficient. The threshold of prediction of a bleeding intervention was optimized by a ROC analysis.

RESULTS

Overall, 166 patients were included. Most patients were male (80.7%) with a median age of 44 years. Using the prediction from the MiGUTS nomogram developed by Keihani et al. we were able to identify a threshold with a sensitivity of 1.00, specificity of 0.87, positive predictive value of 0.44, negative predictive value of 1.00 and accuracy of 0.88.

CONCLUSION

The MiGUTS nomogram by Keihani et al. demonstrated to be reliable in the prediction of an intervention for bleeding control in our validation study in a European cohort.

Renal embolization for trauma: a narrative review

Renal injuries commonly occur in association with blunt trauma, especially in the setting of motor vehicle accidents. Contrast-enhanced computed tomography is considered the gold-standard imaging modality to assess patients for renal injuries in the setting of blunt and penetrating trauma, and to help classify injuries based on the American Association for the Surgery of Trauma injury scoring scale. The management of renal trauma has evolved in the past several decades, with a notable shift towards a more conservative, nonoperative approach. Advancements in imaging and interventional radiological techniques have enabled diagnostic angiography with angiographic catheter-directed embolization to become a viable option, making it possible to avoid surgical interventions that pose an increased risk of nephrectomy. This review describes the current management of renal trauma, with an emphasis on renal artery embolization techniques.

Proposed revision of the American Association for Surgery of Trauma Renal Organ Injury Scale: Secondary analysis of the Multi-institutional Genitourinary Trauma Study

BACKGROUND

This study updates the American Association for the Surgery of Trauma (AAST) Organ Injury Scale (OIS) for renal trauma using evidence-based criteria for bleeding control intervention.

METHODS

This was a secondary analysis of a multicenter retrospective study including patients with high-grade renal trauma from seven level 1 trauma centers from 2013 to 2018. All eligible patients were assigned new renal trauma grades based on revised criteria. The primary outcome used to measure injury severity was intervention for renal bleeding. Secondary outcomes included intervention for urinary extravasation, units of packed red blood cells transfused within 24 hours, and mortality. To test the revised grading system, we performed mixed-effect logistic regression adjusted for multiple baseline demographic and trauma covariates. We determined the area under the curve (AUC) to assess accuracy of predicting bleeding interventions from the revised grading system and compared this to 2018 AAST OIS.

RESULTS

Based on the 2018 OIS grading system, we included 549 patients with AAST grades III to V injuries and computed tomography scans (III, 52% [n = 284]; IV, 45% [n = 249]; and V, 3% [n = 16]). Among these patients, 89% experienced blunt injury (n = 491), and 12% (n = 64) underwent intervention for bleeding. After applying the revised grading criteria, 60% (n = 329) of patients were downgraded, and 4% (n = 23) were upgraded; 2.8% (n = 7) downgraded from grade V to IV, and 69.5% (n = 173) downgraded from grade IV to III. The revised renal trauma grading system demonstrated improved predictive ability for bleeding interventions (2018 AUC, 0.805; revised AUC, 0.883; p = 0.001) and number of units of packed red blood cells transfused. When we removed urinary injury from the revised system, there was no difference in its predictive ability for renal hemorrhage intervention.

CONCLUSION

A revised renal trauma grading system better delineates the need for hemostatic interventions than the current AAST OIS renal trauma grading system.

LEVEL OF EVIDENCE

Diagnostic Test/Criteria; Level III.

Shattered Kidney After Renal Trauma: Should It Be Classified As an American Association for the Surgery of Trauma Grade V Injury?

OBJECTIVE

To study the prevalence and management of shattered kidney and to evaluate if the new description of "loss of identifiable renal anatomy" in the 2018 American Association for the Surgery of Trauma (AAST) organ injury scale (OIS) would improve the ability to predict bleeding control interventions.

METHODS

We used high-grade renal trauma data from 21 Level-1 trauma centers from 2013 to 2018. Initial CT scans were reviewed to identify shattered kidneys, defined as a kidney having ≥3 parenchymal fragments displaced by blood or fluid on cross-sectional imaging. We further categorized patients with shattered kidney in two models based on loss of identifiable renal parenchymal anatomy and presence or absence of vascular contrast extravasation (VCE). Bleeding interventions were compared between the groups.

RESULTS

From 861 high-grade renal trauma patients, 41 (4.8%) had shattered kidney injury. 25 (61%) underwent a bleeding control intervention including 18 (43.9%) nephrectomies and 11 (26.8%) angioembolizations. 18 (41%) had shattered kidney with "loss of identifiable parenchymal renal anatomy" per 2018 AAST OIS (model-1). 28 (68.3%) had concurrent VCE (model-2). Model-2 had a statistically significant improvement in area under the curve over model-1 in predicting bleeding interventions (0.75 vs 0.72; P = .01).

CONCLUSION

Shattered kidney is associated with high rates of active bleeding, urinary extravasation, and interventions including nephrectomy. The definition of shattered kidney is vague and subjective and our definition might be simpler and more reproducible. Loss of identifiable renal anatomy per the 2018 AAST OIS did not provide better distinction for bleeding control interventions over presence of VCE.

Grade V renal trauma management: results from the multi-institutional genito-urinary trauma study

PURPOSE

To investigate management trends for American Association for the Surgery of Trauma (AAST) grade V renal trauma with focus on non-operative management.

METHODS

We used prospectively collected data as part of the Multi-institutional Genito-Urinary Trauma Study (MiGUTS). We included patients with grade V renal trauma according to the AAST Injury Scoring Scale 2018 update. All cases submitted by participating centers with radiology images available were independently reviewed to confirm renal trauma grade. Management was classified as expectant, conservative (minimally invasive, endoscopic or percutaneous procedures), or operative (renal-related surgery).

RESULTS

Eighty patients were included, 25 of whom had complete imaging and had independent confirmation of AAST grade V renal trauma. Median age was 35 years (Interquartile range (IQR) 25-50) and 23 (92%) had blunt trauma. Ten patients (40%) were managed operatively with nephrectomy. Conservative management was used in nine patients (36%) of which six received angioembolization and three had a stent or drainage tube placed. Expectant management was followed in six (24%) patients. Transfusion requirements were progressively higher with groups requiring more aggressive treatment, and injury characteristics differed significantly across management groups in terms of hematoma size and laceration size. Vascular contrast extravasation was more likely in operatively managed patients though a statistically significant association was not found.

CONCLUSION

Successful use of nonoperative management for grade V injuries is used for a substantial subset of patients. Lower transfusion requirement and less severe injury radiologic phenotype appear to be important characteristics delineating this group.

Nephrectomy After High-Grade Renal Trauma is Associated With Higher Mortality: Results From the Multi-Institutional Genitourinary Trauma Study (MiGUTS)

OBJECTIVE

To test the hypothesis that undergoing nephrectomy after high-grade renal trauma is associated with higher mortality rates.

METHODS

We gathered data from 21 Level-1 trauma centers through the Multi-institutional Genito-Urinary Trauma Study. Patients with high-grade renal trauma were included. We assessed the association between nephrectomy and mortality in all patients and in subgroups of patients after excluding those who died within 24 hours of hospital arrival and those with GCS≤8. We controlled for age, injury severity score (ISS), shock (systolic blood pressure <90 mmHg), and Glasgow Coma Scale (GCS).

RESULTS

A total of 1181 high-grade renal trauma patients were included. Median age was 31 and trauma mechanism was blunt in 78%. Injuries were graded as III, IV, and V in 55%, 34%, and 11%, respectively. There were 96 (8%) mortalities and 129 (11%) nephrectomies. Mortality was higher in the nephrectomy group (21.7% vs 6.5%, P <.001). Those who died were older, had higher ISS, lower GCS, and higher rates of shock. After adjusting for patient and injury characteristics nephrectomy was still associated with higher risk of death (RR: 2.12, 95% CI: 1.26-2.55).

CONCLUSION

Nephrectomy was associated with higher mortality in the acute trauma setting even when controlling for shock, overall injury severity, and head injury. These results may have implications in decision making in acute trauma management for patients not in extremis from renal hemorrhage.