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The predictive value of multidetector CTA on outcomes in patients with below-the-knee vascular injury
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The predictive value of multidetector CTA on outcomes in patients with below-the-knee vascular injury Bernardino C. Branco a, Megan Linnebur b, Mina L. Boutrous c, Samuel S. Leake c, Kenji Inaba b, Kristofer M. Charlton-Ouw c, Ali Azizzadeh c, Gerald Fortuna c, Joseph J. DuBose c,* a
Department of Surgery, University of Arizona, Tucson, AZ, USA Division of Trauma and Surgical Critical Care, University of Southern California, Los Angeles, CA, USA c Department of Cardiothoracic and Vascular Surgery, University of Texas Medical School at Houston, Herman Memorial Hospital, 6400 Fannin St, Suite 2850, Houston, TX 77030, USA b
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 1 June 2015
Background: Multidetector computed tomographic angiography (MDCTA) has become the gold standard for the early assessment of lower extremity vascular injury. The objective of this study was to evaluate the predictive value of MDCTA documented vessel run-off to the foot on limb salvage rates after lower extremity vascular injury. Methods: All trauma patients undergoing lower extremity MDCTA for suspected vascular injury assessed at 2 high-volume Level I trauma centers between January 2009 and December 2012. Demographics, clinical data and outcomes (compartment syndrome requiring fasciotomy and limb salvage) were extracted. The predictive value of MDCTA vessel run-off was tested against an aggregate gold standard of operative intervention, clinical follow-up and all imaging obtained. Results: During the 4-year study period, 398 patients sustained lower extremity trauma and were screened for inclusion into this study. Of those, 166 (41.7%) patients (72.9% at MHH and 27.1% at LAC + USC Medical Center) underwent initial evaluation with MDCTA, 86 (51.8%) had vascular injury below the knee identified by MDCTA. Among these, the average age was 38.0 15.8 years, 80.2% were men and 83.7% sustained a blunt injury mechanism. On admission, 8.1% were hypotensive and the median ISS was 10 (range 1–57). There was a direct correlation between the number of patent vessels to the foot and the need for operative intervention (86.4% with no patent vessels, 56.0% with 1 patent vessel, 33.3% with 2 and 0.0% with 3, p < 0.001). When outcomes were analysed, the rates of fasciotomy for compartment syndrome decreased in a stepwise fashion as the number of patent vessels to the foot increased (63.6% with no patent vessels; 44.0% with 1; 21.2% with 2; and 0.0% with 3; p = 0.003). No amputations occurred in patients with 2 or more patent vessels to the foot (68.2% for no patent vessel; 16.0% for 1; 0.0% for 2; and 0.0% for 3; p < 0.001). Conclusions: In this multicenter evaluation of patients undergoing MDCTA for suspected below-theknee vascular injury, there was a stepwise increase in the need for operative intervention, fasciotomy and amputation as the number of patent vessels to the foot decreased. Published by Elsevier Ltd.
Keywords: Lower extremity vascular trauma Multidetector computed tomography angiography Number of vessel run-offs Compartment syndrome Limb salvage
Introduction Computed tomographic angiography (CTA) has emerged as an important tool in the diagnosis of extremity vascular injury after trauma. Available studies suggest that the sensitivity and specificity of this modality in identifying vascular injury to the
* Corresponding author. Tel.: +1 410 328 0241. E-mail address: [email protected] (J.J. DuBose).
lower extremities exceeds 90% [1–16]. To date, however, the majority of available studies have included predominantly proximal extremity vascular injuries in their analysis. Comparatively less is known about the diagnostic capabilities of CTA in the identification of below-the-knee vascular injuries. Perhaps more importantly, there remains very little data correlating CTA findings to subsequent need for intervention. The importance of documented vascular ‘‘run-off’’ to the distal lower extremity remains a matter of active investigation. Although the optimal treatment of severe extremity injuries remains a
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complex issue, traditional teaching has suggested that the preservation of single-vessel perfusion to the foot provides adequate vascular inflow to facilitate salvage of limbs that do not have devastating soft tissue, bony or neurologic injury. Recent investigators, however, have scrutinised the application of this maxim [17]. The intent of our study was to examine, in a multi-institutional fashion, the CTA evaluation of the below-the-knee vasculature of the lower extremity after trauma. We attempted to correlate positive findings identified on CTA with early clinical outcome. Specifically, we sought to correlate the number of patent arterial vessels to the distal lower extremity to the need for intervention and early limb salvage. Materials and methods After institutional review board approval, all patients with suspected vascular injury to the lower extremity who underwent initial evaluation with multidetector computed tomography angiography (MDCTA) presenting to 2 high-volume Level I trauma centers: the Memorial Herman Hospital-Texas Medical Center (MHH) and to the Los Angeles County + University of Southern California (LAC + USC) Medical Center, between January 1, 2009 and December 31, 2012 were reviewed. The patients were retrospectively screened for inclusion in this study. The inclusion criteria were: (1) age 16 years; (2) injury to the lower extremities (penetrating injury mechanism (gunshot wound, shotgun or stab wound), crush injury to extremities or any blunt mechanism resulting in a long bone fracture or dislocation); and (3) injury site between the knee and ankle. Patients requiring emergency cavitary surgery prior to imaging were excluded from the study. The extremity MDCTA protocol was standardised throughout the study period at both centers (Toshiba Aquilion 64 CFX multislice CT scanner). The following parameters were used: 120 kVp, 200–400 mA s (depending on size of patient, using dose modulation), gantry revolution speed of 0.5 s, beam pitch 0.828, beam collimation of 64 mm 0.5 mm, variable field of view (depending on size of patient), standard body kernel. Through an intravenous line suitable for power contrast injection (18- or 20gauge peripheral IV line in the antecubital fossa or a central venous catheter that has been approved by the manufacturer for power injection), 75–100 cc of Iohexol iodinated IV contrast material (OmnipaqueTM 350; GE Healthcare, Princeton, NJ, USA) was injected at a rate of 4 ml/s followed by a 40 cc saline flush by a Medrad power injector (Spectris; Medrad, Indianola, PA, USA). Contrast bolus tracking was utilised, with a trigger threshold of 180 HU over the region of interest, defined by protocol as the abdominal aorta at the L2–L3 level. Reconstruction with section thickness of 1 mm and 2 mm in the axial, coronal and sagittal planes was performed and additional post processing was performed by the radiologist on a Vitrea1 reformatting workstation (Vital Images, Plymouth, MN, USA) to create volume renderings, maximum-intensity projections, and curved planar reformations as needed. Reconstruction was performed by an attending radiologist or interventional radiology fellow and the final attending read was utilised for the analysis. Demographic and clinical data collected included age, gender, injury mechanism, admission systolic blood pressure (SBP) and Glasgow Coma Scale (GCS) score and 24-h transfusion requirements. All results of imaging and vascular operative procedures were extracted. Injury Severity Score (ISS), Mangled Extremity Severity Score (MESS) [18] hospital length of stay (HLOS), intensive care unit (ICU) LOS, complications (below-the-knee ipsilateral compartment syndrome requiring fasciotomy, acute kidney insufficiency (AKI) surgical site infections (SSI), need for tissue
flap coverage and reoperation for delayed haemorrhage or access site complication), limb salvage rates and mortality were recorded. AKI was defined as elevation of serum creatinine 2.0 mg/dl during hospitalisation without antecedent renal dysfunction. SSI was defined according to the Centers for Disease Control criteria: (1) superficial incisional, affecting the skin and subcutaneous tissue; (2) deep incisional, affecting the fascial and muscle layers; (3) organ or space infection. Continuous variables were dichotomised using the following clinically relevant cut-points: age (55 vs. <55 years), systolic blood pressure at admission (<90 vs. 90 mm Hg) and ISS (16 vs. <16). The primary outcome measures of this study were ipsilateral below the knee compartment syndrome requiring fasciotomy and limb salvage. Secondary outcome measures were mortality, HLOS, ICU LOS, and complications. The predictive value of MDCTA vessel run-off to the foot was tested against an aggregate gold standard of the final diagnosis at discharge, which included operative exploration, catheter-based angiography results and clinical follow-up. The patients were divided into 4 cohorts according to the number of patent vessels to the foot: no patent vessels, 1, 2 and 3 patent vessels. These 4 cohorts were analysed for differences in demographics and clinical characteristics using univariate analysis. Chi-squared or Fisher’s exact tests were used to compare proportions, and analysis of variance was used to compare means. Logistic regression modelling was performed to control for confounders that were significantly different at the p < 0.05 level among the groups. A Cox regression analysis was used to evaluate the association between the number of patent vessels to the foot and primary outcomes adjusting for all factors that had a p < 0.2 from the univariate analysis. Values are reported as means standard deviation (SD); median (range) for continuous variables and as percentage for categorical variables. All analyses were performed using the Statistical Package for Social Sciences (SPSS Macß), version 22.0 (SPSS Inc, Chicago, IL, USA). Results During the 4-year study period, a total of 398 patients sustained a vascular injury to the lower extremity and were screened for inclusion into this study. Of those, 166 (41.7%) (72.9% at MHH and 27.1% at LAC + USC Medical Center) underwent initial evaluation with MDCTA. There were 86 (51.8%) with a vascular injury below the knee. Trauma registry and chart review did not reveal any vascular injuries below the knee missed by CTA or false positive CTAs between the 2 centers. Associated sensitivity and specificity of CTA for the detection of below-the-knee vascular injury was 100%. The average age of the patients undergoing MDCTA was 38.0 15.8 years, 80.2% were men and 83.7% sustained a blunt injury mechanism. On admission, 9.3% were hypotensive, the mean GCS was 14 3 and the median ISS was 10 (range 1–57). When the MESS scores were analysed, overall, 8.1% of patients had limb ischemia time >6 h, 46.5% sustained a medium energy injury mechanism, such as joint dislocation or open/multiple long bone fractures. Approximately 17.3% of patients demonstrated transient or sustained hypotension after hospital admission. Reduced pulse with normal limb perfusion was present in 60.5% of patients. Demographics and clinical data for patient groups are presented in Table 1. A total of 138 positive arterial findings were detected by MDCTA in this study cohort. Overall, 52 (60.5%) patients sustained an injury to the anterior tibial artery, 33 (38.4%) to the posterior tibial artery, 32 (37.2%) to the peroneal artery and 21 (24.4%) to the below-the-knee popliteal artery. The rate of associated venous injury was 12.8% (13 patients). After MDCTA evaluation, 29 (33.7%) patients underwent operative exploration, 25 (29.1%) underwent
Please cite this article in press as: Branco BC, et al. The predictive value of multidetector CTA on outcomes in patients with below-theknee vascular injury. Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.001
0 (n = 22)
1 (n = 25)
2 (n = 33)
3 (n = 6)
Age (y), mean SD; median (range) Male (%) Blunt (%) GSW (%) SBP on admission, mean SD; median (range) SBP on admission < 90 mmHg (%) GCS on admission, mean SD; median (range) ISS, mean SD; median (range) ISS 16 (%) MESS score Limb ischemia for > 6 h (%) Injury mechanism Low energy (GSW, SW, simple fracture) (%) Medium energy (dislocation, open/multiple fractures) (%) High energy (high speed motor vehicle or rifle shot) (%) Very high energy (high speed trauma + gross contamination) (%) Shock SBP > 90 mmHg consistently (%) Transient hypotension (%) Persistent hypotension (%) Limb ischemia Reduced pulse but normal perfusion (%) Pulseless, paresthesias, slow capillary refill (%) Cool, paralysis, numb/insensate (%) Age <30 y (%) 30–50 y (%) >50 y (%) 1 unit of pRBC within 24 h of admission (%)
35.6 15.7; 32 (16–66) 81.8% (18) 100.0% (22) 0.0% (0) 128.9 25.8; 127 (84–175) 4.8% (1) 13 4; 15 (3–15) 17.0 13.5; 12 (4–50) 36.4% (8)
36.7 16.2; 35 (17–70) 80.0% (20) 80.0% (20) 20.0% (5) 116.2 27.6; 110 (55–174) 16.0% (4) 14 2; 15 (7–15) 15.2 9.6; 10 (9–50) 32.0% (8)
42.3 16.2; 43 (16–84) 81.8% (27) 75.8% (25) 24.2% (8) 130.9 28.2; 129 (79–197) 6.5% (2) 14 3; 15 (5–15) 13.6 9.4; 10 (2–50) 30.3% (10)
29.2 6.4; 29 (23–41) 66.7% (4) 83.3% (5) 16.7% (1) 128.3 9.7; 128 (117–145) 0.0% (0) 15 1; 15 (14–15) 13.6 9.4; 10 (2–50) 33.3% (2)
0.172 0.874 0.108 0.108 0.197 0.402 0.357 0.709 0.973
18.2% (4)
4.0% (0)
6.1% (2)
0.0% (0)
0.234
9.1% (2) 31.8% (7) 31.8% (7) 27.3% (6)
8.0% (2) 60.0% (15) 24.0% (6) 8.0% (2)
15.2% (5) 48.5% (16) 27.3% (9) 9.1% (3)
50.0% (3) 33.3% (2) 16.7% (1) 0.0% (0)
0.103
90.9% (20) 0.0% (0) 9.1% (2)
80.0% (20) 8.0% (2) 12.0% (3)
81.8% (27) 9.1% (3) 9.1% (3)
100.0% (6) 0.0% (0) 0.0% (0)
0.736
36.4% (8) 4.5% (1) 59.1% (13)
40.0% (10) 48.0% (12) 12.0% (3)
81.8% (27) 15.2% (5) 3.0% (1)
83.3% (5) 16.7% (1) 0.0% (0)
<0.001*
50.0% 27.3% 22.7% 59.1%
40.0% 44.0% 16.0% 56.0%
21.2% 48.5% 30.3% 42.1%
83.3% (5) 16.7% (1) 0.0% (0) 50.0% (3)
0.046*
(11) (6) (5) (13)
(10) (11) (4) (14)
(7) (16) (10) (14)
p
0.248
The p-values for categorical variables were derived from chi-square or Fisher’s exact tests; p-values for continuous variables were derived from analysis of variance. MDCTA, multi-detector computed tomographic angiography; GSW, gunshot wound; SBP, systolic blood pressure; GCS, Glasgow Coma Scale; ISS, Injury Severity Score; MESS, Mangled Extremity Severity Score and pRBC, packed red blood cells. * p-Values are significantly different (p < 0.05).
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Number of patent vessels to the foot
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Please cite this article in press as: Branco BC, et al. The predictive value of multidetector CTA on outcomes in patients with below-theknee vascular injury. Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.001
Table 1 Demographic and clinical data for patients sustaining below the knee injuries according to the number of patent vessels to the foot on MDCTA.
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Fig. 1. Initial management based on MDCTA findings according to the type of arterial injury.
diagnostic angiography and 32 (37.2%) were observed. Based on angiographic findings, 12 (14.0%) additional patients underwent operative exploration. Fig. 1 depicts initial management according to type of arterial injury on MDCTA. Description of the vascular injuries, according to injury grade and management, are presented in Table 2. On MDCTA, there were 6 (7.0%) patients with 3 patent vessels to the foot, 33 (38.4%) with 2 patent vessels, 25 (29.1%) with 1 patent vessel and 22 (25.6%) with no patent vessel to the foot. Fig. 2 depicts initial management according to the number of patent vessels to the foot on MDCTA. Overall, there was a direct correlation between the number of patent vessels to the foot and the need for operative intervention (86.4% for no patent vessels, 56.0% for 1 patent vessel, 33.3% for 2 patent vessels and 0.0% for 3 patent vessels, p < 0.001). Rates of intervention correlated with the number of patent vessels to the foot. Fasciotomy requirement for compartment syndrome decreased in a stepwise fashion as the number of patent vessels to the foot increased (63.6% for no patent vessels, 44.0% for 1, 21.2% for 2, and 0.0% for 3, p = 0.003). With regard to outcomes, no amputations occurred in patients with 2 or more patent vessels to the foot (68.2% for no patent vessel, 16.0% for 1, 0.0% for 2 and 0.0% for 3, p < 0.001). Table 3 depicts outcomes according to the
number of patent vessels to the foot. Cox regression time to event analysis revealed early separation of primary outcome-free curves for 3 or 2 patent vessels to the foot relative to those patients with 1 or no patent vessels (log-rank: p < 0.001) (Fig. 3). Discussion With advancements in computed tomographic technology, this imaging modality has continued to replace older tools as the screening test of choice to identify injury after trauma. This is particularly evident in the diagnosis of vascular trauma, where the addition of contrast-enhancement via CT angiography has proven a valuable resource in the expedient identification and characterization of arterial injury. Initially employed with success in the diagnosis of large vessel injury, CTA has more recently proven a valuable adjunct in the identification of traumatic sequelae within the smaller vasculature of the distal extremities [1–16]. Seamon et al. [9] described the effective utilization of CTA to diagnose vascular injury among trauma victims with extremity injury and an ankle-brachial systolic blood pressure ratio index <0.9. In this subset of patients, they found that diagnostic CTA had a sensitivity and specificity of 100% for clinically relevant injury detection. A number of additional investigators have published
Table 2 Description of injuries according to injury grade and final management. Injury grade
Mild intimal injury
Dissection
Pseudoaneurysm
Occlusion/thrombosis
Transection
Below the knee popliteal a. (n = 21) Anterior tibial a. (n = 52) Posterior tibial a. (n = 33) Peroneal a. (n = 32)
– – – –
– – 3.0% (1) 6.3% (2)
9.5% (2) – – –
71.5% 72.6% 60.7% 75.0%
19.0% 27.4% 33.3% 18.7%
(15) (37) (20) (24)
(4) (14) (11) (6)
Management
Observation/ medical management
Diagnostic angiography
Endovascular treatment
Primary repair
Thrombectomy/ embolectomy
Interposition with vein
Interposition with synthetic graft
Ligation
Exploration without intervention
Below the knee popliteal a. (n = 21) Anterior tibial a. (n = 52) Posterior tibial a. (n = 33) Peroneal a. (n = 32)
9.5% (2)
42.8% (9)
4.8% (1)
9.5% (2)
19.0% (4)
66.7% (14)
4.8% (1)
–
9.5% (2)
63.5% (33) 60.6% (20) 62.5% (20)
40.4% (21) 45.5% (15) 46.9% (15)
– – –
– 6.1% (2) 3.1% (1)
1.9% (1) – 6.3% (2)
34.6% (18) 27.3% (9) 28.1% (9)
– – 3.1% (1)
– 3.0% (1) 3.1% (1)
7.7% (4) 12.1% (4) 9.4% (3)
A total of 138 injuries in 86 patients with positive findings on MDCTA were included in this analysis.
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Fig. 2. Initial management based on MDCTA findings according to the number of patent vessels to the foot.
similar single-center retrospective experiences that have demonstrated sensitivity and specificity of CTA for the identification of vascular injury at greater than 90% [1,2,4–8,10–16]. Inaba et al. [3] examined the use of CTA in a prospective fashion, reporting on the single-center evaluation of 73 patients with soft signs of vascular injury. They identified 24 positive studies, yielding a sensitivity and specificity of 100% for the detection of clinically relevant vascular injuries. In the largest meta-analysis of the literature on the topic, Jens et al. [12] identified 11 studies comprising 891 trauma patients evaluated with CTA following injury. Summary estimates of sensitivity and specificity in this analysis were 96.2% and 99.2%, respectively. This group of researchers noted a cumulative nondiagnostic rate for CTA of 4.2% among available published experiences. These successes suggest that CTA of the injured extremity, when employed in the context of a thoughtful clinical evaluation, has the potential to provide accurate and expedient identification of vascular injury. Although the aforementioned data on CTA use after extremity injury is encouraging, the majority of published experience on the use of this modality in lower extremity evaluation has reported on more proximal arterial injuries. Comparatively less is known about
the value of CTA in predicting need for treatment and outcome of the more distal lower extremity below the knee. In the previously mentioned report by Seamon et al., the investigators identified only 3 injuries below the distal popliteal artery [9]. The important prospective effort conducted by Inaba et al. found only a single positive study described below the level of the trifurcation of the popliteal into the anterior tibial, peroneal and posterior tibial arteries [3]. The value of CT identification and characterisation of these distal injuries is important, as injury to the trifurcation outflow may represent significant challenges relative to more proximal injuries. Lazarides et al. [19] investigated this subset of patients, concluding that victims of trauma with injuries involving the trifurcation outflow may have a risk of subsequent amputation of approximately 70%. While CTA appears to have improved our ability to expediently identify and even characterise distal lower extremity injuries, there remains a need to correlate these findings with subsequent need for intervention and outcome. In particular, it is unknown what degree of perfusion is necessary for limb salvage. Traditional teaching has suggested that single-vessel outflow to the foot may prove adequate for healing and limb salvage. In a contemporary,
Table 3 Outcomes. Number of patent vessels to the foot
0 (n = 22)
1 (n = 25)
2 (n = 33)
3 (n = 6)
Fasciotomy (%) Acute renal failure (%) Surgical site infection (%) Need for tissue flap coverage (%) Need for re-operation for delayed hemorrhage or access site complication (%) Major limb amputation (AKA or BKA) (%) Mortality (%) HLOS, mean SD; median (range) ICU LOS, mean SD; median (range)
63.6% (14) 9.1% (2) 22.7% (5) 22.7% (5) 13.6% (3)
44.0% (11) 20.0% (5) 4.0% (1) 16.0% (4) 4.0% (1)
21.2% (7) 9.1% (3) 0.0% (0) 24.2% (8) 3.0% (1)
0.0% (0) 0.0% (0) 16.7% (1) 0.0% (0) 0.0% (0)
68.2% (15) 4.5% (1) 23.6 15.0; 17 (7–51) 4.8 8.4; 2 (1–38)
16.0% (4) 8.0% (2) 22.2 18.9; 16 (2–73) 4.7 6.5; 2 (1–25)
0.0% (0) 0.0% (0) 18.6 9.8; 17 (1–49) 3.6 5.2; 3 (1–23)
0.0% (0) 0.0% (0) 14.5 4.8; 16 (8–21) 2.2 3.6; 1 (1–9)
Adjusted p 0.003* 0.417 0.016* 0.524 0.328 <0.001* 0.393 0.736 0.391
The p-values were derived from multivariable analysis for ICU LOS and HLOS; and from bivariate analysis for complications and mortality. The p-values were obtained after adjustment for MESS scores. AKA, above knee amputation; BKA, below knee amputation; HLOS, hospital length of stay; ICU, intensive care unit. * p-Values are significantly different (p < 0.05).
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Fig. 3. Primary outcomes according to the number of patent vessels to the foot: (a) below-the-knee compartment syndrome requiring fasciotomy; (b) major amputation (AKA or BKA).
retrospective, single-center study of the topic, however, Dua et al. [17] identified a significant failure rate associated with this approach. In their small series of 36 patients with trifurcation outflow injuries identified by CTA, they noted that patients with single-vessel outflow on imaging failed observation in 37.5%. Our presently reported multicenter results support this finding. We noted that 56% of patients with only single vessel outflow identified on extremity CTA required operative intervention. As with the findings of Dua et al. [17], we noted a stepwise relationship between the number of patent uninjured vessels identified on CTA and subsequent successful nonoperative observation. When considering our present results, it is important to note that successful limb salvage remains a complex issue that is not entirely dictated by the presence or degree of vascular injury alone. Several groups have previously conducted thoughtful, multicenter examinations designed to develop effective criteria for predicting outcome after severe lower extremity injury, with disappointing results [20–22]. The interplay of factors requiring consideration, including nerve, soft tissue, bony and vascular elements of injury, require careful multidisciplinary collaboration [23]. It is the hope, however, that our present results will contribute to an improved understanding of the risk to the injured limb relative to the vascular elements of consideration. The ultimate goal of vascular limb salvage remains the restoration or preservation of adequate perfusion to the distal limb/foot to support healing and functional requirements. The assessment of vascular limb salvage relies on a thoughtful evaluation beginning with initial clinical exam/ABI assessment and appropriate utilization of CTA or angiography to identify and triage vascular injury. Additional objective assessments may also be of important clinical utility, including the use of toe pressures by plethysmography or other advanced assessments to determine the adequacy of distal perfusion. It is important to note that almost half of the patients in our study with single-vessel run-off to the foot had limb salvage without the use of tibial revascularization using a variety of individualised assessment approaches. The utility of these adjuncts in single-vessel run-off has not been well studied in a multi-institutional fashion and requires additional study. Similarly, the outcome associated with revascularization of
single-vessel run-off in the injured limb requires additional investigation. Our study has several important limitations that must be recognised. The retrospective design precluded the effective capture of key information, including initial bedside ankle-brachial index assessment and other granularities of the physical exam that may be important in guiding the decision for both CTA evaluation and subsequent operative intervention. There is also likely a significant selection bias to the use of CTA relative to injured extremities in our series. Patients with severe soft tissue or bony injuries may have been taken directly to the operative theater for more expedient intervention, thereby bypassing CTA in favour of intraoperative Doppler ultrasound or traditional angiographic evaluation. While we were able to identify the individual elements of the MESS score through registry and chart review (Table 1), the heterogeneous nature of these injuries compromises our ability to precisely comment on the impact of individual injury elements in dictating the need for subsequent operative intervention. In addition, some defined complications were abstracted from the trauma registries of the respective study institutions. The criteria utilised to define these specific complications, most notably that of Acute Kidney Injury (AKI), while consistent to each specific registry, may have changed over time and differ slightly between centers. The ability to link to source data beyond registry variables for these definitions was limited due to the retrospective nature of our study. Finally, our study only recorded initial hospitalization outcomes. We cannot, therefore, comment on subsequent postdischarge functional outcomes of the patients identified. Patients with dense nerve injuries are left with a viable extremity that is functionless. While they initially refuse amputation, it is our experience that these patients often return to request an elective amputation many months after their injury. Conclusion We hope this multicenter study provides additional insight into the utility of CTA evaluation of the injured distal lower extremity. While significant additional study is required, our present effort provides evidence that the number of patent trifurcation outflow vessels on CTA correlates with subsequent need for intervention. We hope that this information can be utilised in the multidisciplinary evaluation of the injured extremity to guide informed decisions regarding intervention, including the need for revascularization of distal outflow vessels to the lower extremity. Conflicts of interest The authors declare that there are no conflicts of interest or disclosures of any kind to report in regard to this manuscript. References [1] Peng PD, Spain DA, Tataira M, Hellinger JC, Rubin GD, Brundage SI. CT angiography effectively evaluates extremity vascular trauma. Am Surg 2008 Feb;74(2):103–7. [2] Inaba K, Potzman J, Munera F, McKenney M, Munoz R, Rivas L, et al. Multi-slice CT angiography for arterial evaluation in the injured lower extremity. J Trauma 2006;60(Mar (3)):502–6 [discussion 506–507]. [3] Inaba K, Branco B, Reddy S, Park JJ, Green D, Plurad D, et al. Prospective evaluation of multidetector computed tomography for extremity vascular trauma. J Trauma 2011;70(Apr (4)):808–15. [4] Rieger M, Mallhoui A, Tauscher T, Lutz M, Jaschke WR. Traumatic arterial injuries to the extremities: initial evaluation with MDCT angiography. AJR Am J Roentgenol 2006;186(Mar (3)):656–64. [5] Busquets AR, Acosta JA, Colon E, Alejandro KV, Rodriguez P. Helical computed tomographic angiography for the diagnosis of traumatic arterial injuries of the extremities. J Trauma 2004;56(Mar (3)):625–8. [6] Soto JA, Munera F, Cardoso N, Guarin O, Medina S. Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities. J Comput Assist Tomogr 1999;23(Mar–Apr (2)):188–96.
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JINJ-6239; No. of Pages 7 B.C. Branco et al. / Injury, Int. J. Care Injured xxx (2015) xxx–xxx [7] Soto JA, Munera F, Morales C, Lopera JE, Holguin D, Guarin O, et al. Focal arterial injuries of the proximal extremities: helical CT arteriography as the initial method of diagnosis. Radiology 2001;218(Jan (1)):188–94. [8] Anderson SW, Foster BR, Soto JA. Upper extremity angiography in penetrating trauma: use of 64-section multidetector CT. Radiology 2008;249(Dec (3)):1064–73. [9] Seamon MJ, Smoger D, Torres DM, Pathak AS, Gaughan JP, Santora TA, et al. A prospective validation of a current practice: the detection of extremity vascular injury with CT angiography. J Trauma 2009;67(Aug (2)):238–43 [discussion 243–244]. [10] Wallin D, Yaghoubian A, Rosing D, Walot I, Chauvapun J, de Virgilio C. Computed tomographic angiography as the primary diagnostic modality in penetrating lower extremity vascular injuries: a level I trauma experience. Ann Vasc Surg 2011;25(Jul (5)):620–3. [11] Gakhal MS, Sartip KA. CT angiography signs of lower extremity vascular trauma. AJR Am J Roentgenol 2009;193(Jul (1)):W49–57. [12] Jens S, Kerstens MK, Legemate DA, Reekers JA, Bipat S, Koelemay MJ. Diagnostic performance of computed tomography angiography in peripheral arterial injury due to trauma: a systematic review and meta-analysis. Eur J Vasc Endovasc Surg 2013;46(Sep (3)):329–37. [13] Peironi S, Foster BR, Anderson SW, Kertesz JL, Rhea JT, Soto JA. Use of 64-row multidetector CT angiography in blunt and penetrating trauma of the upper and lower extremities. Radiographics 2009;29(May–Jun (3)):863–76. [14] Foster BR, Anderson SW, Uyeda JW, Brooks JG, Soto JA. Integration of 64detector lower extremity CT angiography into whole body trauma imaging: feasibility and early experience. Radiology 2011;261(Dec (3)):787–95.
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[15] Patterson BO, Holt PJ, Cleanthis M, Tai N, Carrell T, Loosemore TM, et al. Imaging vascular trauma. Br J Surg 2012;99(Apr (4)):494–505. [16] LeBus GF, Collinge C. Vascular abnormalities as assessed with CT angiography in high energy tibial plafond fractures. J Orthop Trauma 2008;22(Jan (1)):16–22. [17] Dua A, Desai SS, Johnston S, Chinapuvvula NR, DuBose J, Charlton-Ouw K, et al. Observation may be an inadequate approach for injured extremities with single tibial vessel fun-off. Vascular 2014 [Oct 9, pii: 1708538114554925, Epub ahead of print]. [18] Johansen K, Daines M, Howey T, Helfet D, Hansen Jr ST. Objective criteria accurately predict amputation following lower extremity trauma. J Trauma 1990;30(May (5)):568–72 [discussion 572–573]. [19] Lazarides MK, Arvanitis DP, Kopadis GC, Tsoupanos SS, Dayantas JN. Popliteal artery and trifurcation injuries: is it possible to predict outcome? Eur J Vasc Surg 1994;8(Mar (2)):226–30. [20] Rush Jr RM, Arrington ED, Hsu JR. Management of complex extremity injuries: tourniquets, compartment syndrome detection, fasciotomy and amputation care. Surg Clin North Am 2012;92(Aug (4)):987–1007. [21] Ly TV, Travison TG, Castillo RC, Bosse MJ, Mackenzie EJ, LEAP Study Group. Ability of lower-extremity injury severity scores to predict functional outcome after limb salvage. J Bone Joint Surg Am 2008;90(Aug (8)):1738–43. [22] Mackenzie EJ, Bosse MJ, Kellam JF, Burgess AR, Webb LX, Swiontkowski MF, et al. Factors influencing the decision to amputate or reconstruct after high energy lower extremity trauma. J Trauma 2002;52(Apr (4)):641–9. [23] Scalea TM, DuBose J, Moore EE, West M, Moore FA, McIntyre R, et al. Western Trauma Association critical decisions in trauma: management of mangled extremity. J Trauma Acute Care Surg 2012;72(Jan (1)):86–93.
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The predictive value of multidetector CTA on outcomes in patients with below-the-knee vascular injury Bernardino C. Branco a, Megan Linnebur b, Mina L. Boutrous c, Samuel S. Leake c, Kenji Inaba b, Kristofer M. Charlton-Ouw c, Ali Azizzadeh c, Gerald Fortuna c, Joseph J. DuBose c,* a
Department of Surgery, University of Arizona, Tucson, AZ, USA Division of Trauma and Surgical Critical Care, University of Southern California, Los Angeles, CA, USA c Department of Cardiothoracic and Vascular Surgery, University of Texas Medical School at Houston, Herman Memorial Hospital, 6400 Fannin St, Suite 2850, Houston, TX 77030, USA b
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 1 June 2015
Background: Multidetector computed tomographic angiography (MDCTA) has become the gold standard for the early assessment of lower extremity vascular injury. The objective of this study was to evaluate the predictive value of MDCTA documented vessel run-off to the foot on limb salvage rates after lower extremity vascular injury. Methods: All trauma patients undergoing lower extremity MDCTA for suspected vascular injury assessed at 2 high-volume Level I trauma centers between January 2009 and December 2012. Demographics, clinical data and outcomes (compartment syndrome requiring fasciotomy and limb salvage) were extracted. The predictive value of MDCTA vessel run-off was tested against an aggregate gold standard of operative intervention, clinical follow-up and all imaging obtained. Results: During the 4-year study period, 398 patients sustained lower extremity trauma and were screened for inclusion into this study. Of those, 166 (41.7%) patients (72.9% at MHH and 27.1% at LAC + USC Medical Center) underwent initial evaluation with MDCTA, 86 (51.8%) had vascular injury below the knee identified by MDCTA. Among these, the average age was 38.0 15.8 years, 80.2% were men and 83.7% sustained a blunt injury mechanism. On admission, 8.1% were hypotensive and the median ISS was 10 (range 1–57). There was a direct correlation between the number of patent vessels to the foot and the need for operative intervention (86.4% with no patent vessels, 56.0% with 1 patent vessel, 33.3% with 2 and 0.0% with 3, p < 0.001). When outcomes were analysed, the rates of fasciotomy for compartment syndrome decreased in a stepwise fashion as the number of patent vessels to the foot increased (63.6% with no patent vessels; 44.0% with 1; 21.2% with 2; and 0.0% with 3; p = 0.003). No amputations occurred in patients with 2 or more patent vessels to the foot (68.2% for no patent vessel; 16.0% for 1; 0.0% for 2; and 0.0% for 3; p < 0.001). Conclusions: In this multicenter evaluation of patients undergoing MDCTA for suspected below-theknee vascular injury, there was a stepwise increase in the need for operative intervention, fasciotomy and amputation as the number of patent vessels to the foot decreased. Published by Elsevier Ltd.
Keywords: Lower extremity vascular trauma Multidetector computed tomography angiography Number of vessel run-offs Compartment syndrome Limb salvage
Introduction Computed tomographic angiography (CTA) has emerged as an important tool in the diagnosis of extremity vascular injury after trauma. Available studies suggest that the sensitivity and specificity of this modality in identifying vascular injury to the
* Corresponding author. Tel.: +1 410 328 0241. E-mail address: [email protected] (J.J. DuBose).
lower extremities exceeds 90% [1–16]. To date, however, the majority of available studies have included predominantly proximal extremity vascular injuries in their analysis. Comparatively less is known about the diagnostic capabilities of CTA in the identification of below-the-knee vascular injuries. Perhaps more importantly, there remains very little data correlating CTA findings to subsequent need for intervention. The importance of documented vascular ‘‘run-off’’ to the distal lower extremity remains a matter of active investigation. Although the optimal treatment of severe extremity injuries remains a
http://dx.doi.org/10.1016/j.injury.2015.06.001 0020–1383/Published by Elsevier Ltd.
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complex issue, traditional teaching has suggested that the preservation of single-vessel perfusion to the foot provides adequate vascular inflow to facilitate salvage of limbs that do not have devastating soft tissue, bony or neurologic injury. Recent investigators, however, have scrutinised the application of this maxim [17]. The intent of our study was to examine, in a multi-institutional fashion, the CTA evaluation of the below-the-knee vasculature of the lower extremity after trauma. We attempted to correlate positive findings identified on CTA with early clinical outcome. Specifically, we sought to correlate the number of patent arterial vessels to the distal lower extremity to the need for intervention and early limb salvage. Materials and methods After institutional review board approval, all patients with suspected vascular injury to the lower extremity who underwent initial evaluation with multidetector computed tomography angiography (MDCTA) presenting to 2 high-volume Level I trauma centers: the Memorial Herman Hospital-Texas Medical Center (MHH) and to the Los Angeles County + University of Southern California (LAC + USC) Medical Center, between January 1, 2009 and December 31, 2012 were reviewed. The patients were retrospectively screened for inclusion in this study. The inclusion criteria were: (1) age 16 years; (2) injury to the lower extremities (penetrating injury mechanism (gunshot wound, shotgun or stab wound), crush injury to extremities or any blunt mechanism resulting in a long bone fracture or dislocation); and (3) injury site between the knee and ankle. Patients requiring emergency cavitary surgery prior to imaging were excluded from the study. The extremity MDCTA protocol was standardised throughout the study period at both centers (Toshiba Aquilion 64 CFX multislice CT scanner). The following parameters were used: 120 kVp, 200–400 mA s (depending on size of patient, using dose modulation), gantry revolution speed of 0.5 s, beam pitch 0.828, beam collimation of 64 mm 0.5 mm, variable field of view (depending on size of patient), standard body kernel. Through an intravenous line suitable for power contrast injection (18- or 20gauge peripheral IV line in the antecubital fossa or a central venous catheter that has been approved by the manufacturer for power injection), 75–100 cc of Iohexol iodinated IV contrast material (OmnipaqueTM 350; GE Healthcare, Princeton, NJ, USA) was injected at a rate of 4 ml/s followed by a 40 cc saline flush by a Medrad power injector (Spectris; Medrad, Indianola, PA, USA). Contrast bolus tracking was utilised, with a trigger threshold of 180 HU over the region of interest, defined by protocol as the abdominal aorta at the L2–L3 level. Reconstruction with section thickness of 1 mm and 2 mm in the axial, coronal and sagittal planes was performed and additional post processing was performed by the radiologist on a Vitrea1 reformatting workstation (Vital Images, Plymouth, MN, USA) to create volume renderings, maximum-intensity projections, and curved planar reformations as needed. Reconstruction was performed by an attending radiologist or interventional radiology fellow and the final attending read was utilised for the analysis. Demographic and clinical data collected included age, gender, injury mechanism, admission systolic blood pressure (SBP) and Glasgow Coma Scale (GCS) score and 24-h transfusion requirements. All results of imaging and vascular operative procedures were extracted. Injury Severity Score (ISS), Mangled Extremity Severity Score (MESS) [18] hospital length of stay (HLOS), intensive care unit (ICU) LOS, complications (below-the-knee ipsilateral compartment syndrome requiring fasciotomy, acute kidney insufficiency (AKI) surgical site infections (SSI), need for tissue
flap coverage and reoperation for delayed haemorrhage or access site complication), limb salvage rates and mortality were recorded. AKI was defined as elevation of serum creatinine 2.0 mg/dl during hospitalisation without antecedent renal dysfunction. SSI was defined according to the Centers for Disease Control criteria: (1) superficial incisional, affecting the skin and subcutaneous tissue; (2) deep incisional, affecting the fascial and muscle layers; (3) organ or space infection. Continuous variables were dichotomised using the following clinically relevant cut-points: age (55 vs. <55 years), systolic blood pressure at admission (<90 vs. 90 mm Hg) and ISS (16 vs. <16). The primary outcome measures of this study were ipsilateral below the knee compartment syndrome requiring fasciotomy and limb salvage. Secondary outcome measures were mortality, HLOS, ICU LOS, and complications. The predictive value of MDCTA vessel run-off to the foot was tested against an aggregate gold standard of the final diagnosis at discharge, which included operative exploration, catheter-based angiography results and clinical follow-up. The patients were divided into 4 cohorts according to the number of patent vessels to the foot: no patent vessels, 1, 2 and 3 patent vessels. These 4 cohorts were analysed for differences in demographics and clinical characteristics using univariate analysis. Chi-squared or Fisher’s exact tests were used to compare proportions, and analysis of variance was used to compare means. Logistic regression modelling was performed to control for confounders that were significantly different at the p < 0.05 level among the groups. A Cox regression analysis was used to evaluate the association between the number of patent vessels to the foot and primary outcomes adjusting for all factors that had a p < 0.2 from the univariate analysis. Values are reported as means standard deviation (SD); median (range) for continuous variables and as percentage for categorical variables. All analyses were performed using the Statistical Package for Social Sciences (SPSS Macß), version 22.0 (SPSS Inc, Chicago, IL, USA). Results During the 4-year study period, a total of 398 patients sustained a vascular injury to the lower extremity and were screened for inclusion into this study. Of those, 166 (41.7%) (72.9% at MHH and 27.1% at LAC + USC Medical Center) underwent initial evaluation with MDCTA. There were 86 (51.8%) with a vascular injury below the knee. Trauma registry and chart review did not reveal any vascular injuries below the knee missed by CTA or false positive CTAs between the 2 centers. Associated sensitivity and specificity of CTA for the detection of below-the-knee vascular injury was 100%. The average age of the patients undergoing MDCTA was 38.0 15.8 years, 80.2% were men and 83.7% sustained a blunt injury mechanism. On admission, 9.3% were hypotensive, the mean GCS was 14 3 and the median ISS was 10 (range 1–57). When the MESS scores were analysed, overall, 8.1% of patients had limb ischemia time >6 h, 46.5% sustained a medium energy injury mechanism, such as joint dislocation or open/multiple long bone fractures. Approximately 17.3% of patients demonstrated transient or sustained hypotension after hospital admission. Reduced pulse with normal limb perfusion was present in 60.5% of patients. Demographics and clinical data for patient groups are presented in Table 1. A total of 138 positive arterial findings were detected by MDCTA in this study cohort. Overall, 52 (60.5%) patients sustained an injury to the anterior tibial artery, 33 (38.4%) to the posterior tibial artery, 32 (37.2%) to the peroneal artery and 21 (24.4%) to the below-the-knee popliteal artery. The rate of associated venous injury was 12.8% (13 patients). After MDCTA evaluation, 29 (33.7%) patients underwent operative exploration, 25 (29.1%) underwent
Please cite this article in press as: Branco BC, et al. The predictive value of multidetector CTA on outcomes in patients with below-theknee vascular injury. Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.001
0 (n = 22)
1 (n = 25)
2 (n = 33)
3 (n = 6)
Age (y), mean SD; median (range) Male (%) Blunt (%) GSW (%) SBP on admission, mean SD; median (range) SBP on admission < 90 mmHg (%) GCS on admission, mean SD; median (range) ISS, mean SD; median (range) ISS 16 (%) MESS score Limb ischemia for > 6 h (%) Injury mechanism Low energy (GSW, SW, simple fracture) (%) Medium energy (dislocation, open/multiple fractures) (%) High energy (high speed motor vehicle or rifle shot) (%) Very high energy (high speed trauma + gross contamination) (%) Shock SBP > 90 mmHg consistently (%) Transient hypotension (%) Persistent hypotension (%) Limb ischemia Reduced pulse but normal perfusion (%) Pulseless, paresthesias, slow capillary refill (%) Cool, paralysis, numb/insensate (%) Age <30 y (%) 30–50 y (%) >50 y (%) 1 unit of pRBC within 24 h of admission (%)
35.6 15.7; 32 (16–66) 81.8% (18) 100.0% (22) 0.0% (0) 128.9 25.8; 127 (84–175) 4.8% (1) 13 4; 15 (3–15) 17.0 13.5; 12 (4–50) 36.4% (8)
36.7 16.2; 35 (17–70) 80.0% (20) 80.0% (20) 20.0% (5) 116.2 27.6; 110 (55–174) 16.0% (4) 14 2; 15 (7–15) 15.2 9.6; 10 (9–50) 32.0% (8)
42.3 16.2; 43 (16–84) 81.8% (27) 75.8% (25) 24.2% (8) 130.9 28.2; 129 (79–197) 6.5% (2) 14 3; 15 (5–15) 13.6 9.4; 10 (2–50) 30.3% (10)
29.2 6.4; 29 (23–41) 66.7% (4) 83.3% (5) 16.7% (1) 128.3 9.7; 128 (117–145) 0.0% (0) 15 1; 15 (14–15) 13.6 9.4; 10 (2–50) 33.3% (2)
0.172 0.874 0.108 0.108 0.197 0.402 0.357 0.709 0.973
18.2% (4)
4.0% (0)
6.1% (2)
0.0% (0)
0.234
9.1% (2) 31.8% (7) 31.8% (7) 27.3% (6)
8.0% (2) 60.0% (15) 24.0% (6) 8.0% (2)
15.2% (5) 48.5% (16) 27.3% (9) 9.1% (3)
50.0% (3) 33.3% (2) 16.7% (1) 0.0% (0)
0.103
90.9% (20) 0.0% (0) 9.1% (2)
80.0% (20) 8.0% (2) 12.0% (3)
81.8% (27) 9.1% (3) 9.1% (3)
100.0% (6) 0.0% (0) 0.0% (0)
0.736
36.4% (8) 4.5% (1) 59.1% (13)
40.0% (10) 48.0% (12) 12.0% (3)
81.8% (27) 15.2% (5) 3.0% (1)
83.3% (5) 16.7% (1) 0.0% (0)
<0.001*
50.0% 27.3% 22.7% 59.1%
40.0% 44.0% 16.0% 56.0%
21.2% 48.5% 30.3% 42.1%
83.3% (5) 16.7% (1) 0.0% (0) 50.0% (3)
0.046*
(11) (6) (5) (13)
(10) (11) (4) (14)
(7) (16) (10) (14)
p
0.248
The p-values for categorical variables were derived from chi-square or Fisher’s exact tests; p-values for continuous variables were derived from analysis of variance. MDCTA, multi-detector computed tomographic angiography; GSW, gunshot wound; SBP, systolic blood pressure; GCS, Glasgow Coma Scale; ISS, Injury Severity Score; MESS, Mangled Extremity Severity Score and pRBC, packed red blood cells. * p-Values are significantly different (p < 0.05).
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Number of patent vessels to the foot
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Table 1 Demographic and clinical data for patients sustaining below the knee injuries according to the number of patent vessels to the foot on MDCTA.
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Fig. 1. Initial management based on MDCTA findings according to the type of arterial injury.
diagnostic angiography and 32 (37.2%) were observed. Based on angiographic findings, 12 (14.0%) additional patients underwent operative exploration. Fig. 1 depicts initial management according to type of arterial injury on MDCTA. Description of the vascular injuries, according to injury grade and management, are presented in Table 2. On MDCTA, there were 6 (7.0%) patients with 3 patent vessels to the foot, 33 (38.4%) with 2 patent vessels, 25 (29.1%) with 1 patent vessel and 22 (25.6%) with no patent vessel to the foot. Fig. 2 depicts initial management according to the number of patent vessels to the foot on MDCTA. Overall, there was a direct correlation between the number of patent vessels to the foot and the need for operative intervention (86.4% for no patent vessels, 56.0% for 1 patent vessel, 33.3% for 2 patent vessels and 0.0% for 3 patent vessels, p < 0.001). Rates of intervention correlated with the number of patent vessels to the foot. Fasciotomy requirement for compartment syndrome decreased in a stepwise fashion as the number of patent vessels to the foot increased (63.6% for no patent vessels, 44.0% for 1, 21.2% for 2, and 0.0% for 3, p = 0.003). With regard to outcomes, no amputations occurred in patients with 2 or more patent vessels to the foot (68.2% for no patent vessel, 16.0% for 1, 0.0% for 2 and 0.0% for 3, p < 0.001). Table 3 depicts outcomes according to the
number of patent vessels to the foot. Cox regression time to event analysis revealed early separation of primary outcome-free curves for 3 or 2 patent vessels to the foot relative to those patients with 1 or no patent vessels (log-rank: p < 0.001) (Fig. 3). Discussion With advancements in computed tomographic technology, this imaging modality has continued to replace older tools as the screening test of choice to identify injury after trauma. This is particularly evident in the diagnosis of vascular trauma, where the addition of contrast-enhancement via CT angiography has proven a valuable resource in the expedient identification and characterization of arterial injury. Initially employed with success in the diagnosis of large vessel injury, CTA has more recently proven a valuable adjunct in the identification of traumatic sequelae within the smaller vasculature of the distal extremities [1–16]. Seamon et al. [9] described the effective utilization of CTA to diagnose vascular injury among trauma victims with extremity injury and an ankle-brachial systolic blood pressure ratio index <0.9. In this subset of patients, they found that diagnostic CTA had a sensitivity and specificity of 100% for clinically relevant injury detection. A number of additional investigators have published
Table 2 Description of injuries according to injury grade and final management. Injury grade
Mild intimal injury
Dissection
Pseudoaneurysm
Occlusion/thrombosis
Transection
Below the knee popliteal a. (n = 21) Anterior tibial a. (n = 52) Posterior tibial a. (n = 33) Peroneal a. (n = 32)
– – – –
– – 3.0% (1) 6.3% (2)
9.5% (2) – – –
71.5% 72.6% 60.7% 75.0%
19.0% 27.4% 33.3% 18.7%
(15) (37) (20) (24)
(4) (14) (11) (6)
Management
Observation/ medical management
Diagnostic angiography
Endovascular treatment
Primary repair
Thrombectomy/ embolectomy
Interposition with vein
Interposition with synthetic graft
Ligation
Exploration without intervention
Below the knee popliteal a. (n = 21) Anterior tibial a. (n = 52) Posterior tibial a. (n = 33) Peroneal a. (n = 32)
9.5% (2)
42.8% (9)
4.8% (1)
9.5% (2)
19.0% (4)
66.7% (14)
4.8% (1)
–
9.5% (2)
63.5% (33) 60.6% (20) 62.5% (20)
40.4% (21) 45.5% (15) 46.9% (15)
– – –
– 6.1% (2) 3.1% (1)
1.9% (1) – 6.3% (2)
34.6% (18) 27.3% (9) 28.1% (9)
– – 3.1% (1)
– 3.0% (1) 3.1% (1)
7.7% (4) 12.1% (4) 9.4% (3)
A total of 138 injuries in 86 patients with positive findings on MDCTA were included in this analysis.
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Fig. 2. Initial management based on MDCTA findings according to the number of patent vessels to the foot.
similar single-center retrospective experiences that have demonstrated sensitivity and specificity of CTA for the identification of vascular injury at greater than 90% [1,2,4–8,10–16]. Inaba et al. [3] examined the use of CTA in a prospective fashion, reporting on the single-center evaluation of 73 patients with soft signs of vascular injury. They identified 24 positive studies, yielding a sensitivity and specificity of 100% for the detection of clinically relevant vascular injuries. In the largest meta-analysis of the literature on the topic, Jens et al. [12] identified 11 studies comprising 891 trauma patients evaluated with CTA following injury. Summary estimates of sensitivity and specificity in this analysis were 96.2% and 99.2%, respectively. This group of researchers noted a cumulative nondiagnostic rate for CTA of 4.2% among available published experiences. These successes suggest that CTA of the injured extremity, when employed in the context of a thoughtful clinical evaluation, has the potential to provide accurate and expedient identification of vascular injury. Although the aforementioned data on CTA use after extremity injury is encouraging, the majority of published experience on the use of this modality in lower extremity evaluation has reported on more proximal arterial injuries. Comparatively less is known about
the value of CTA in predicting need for treatment and outcome of the more distal lower extremity below the knee. In the previously mentioned report by Seamon et al., the investigators identified only 3 injuries below the distal popliteal artery [9]. The important prospective effort conducted by Inaba et al. found only a single positive study described below the level of the trifurcation of the popliteal into the anterior tibial, peroneal and posterior tibial arteries [3]. The value of CT identification and characterisation of these distal injuries is important, as injury to the trifurcation outflow may represent significant challenges relative to more proximal injuries. Lazarides et al. [19] investigated this subset of patients, concluding that victims of trauma with injuries involving the trifurcation outflow may have a risk of subsequent amputation of approximately 70%. While CTA appears to have improved our ability to expediently identify and even characterise distal lower extremity injuries, there remains a need to correlate these findings with subsequent need for intervention and outcome. In particular, it is unknown what degree of perfusion is necessary for limb salvage. Traditional teaching has suggested that single-vessel outflow to the foot may prove adequate for healing and limb salvage. In a contemporary,
Table 3 Outcomes. Number of patent vessels to the foot
0 (n = 22)
1 (n = 25)
2 (n = 33)
3 (n = 6)
Fasciotomy (%) Acute renal failure (%) Surgical site infection (%) Need for tissue flap coverage (%) Need for re-operation for delayed hemorrhage or access site complication (%) Major limb amputation (AKA or BKA) (%) Mortality (%) HLOS, mean SD; median (range) ICU LOS, mean SD; median (range)
63.6% (14) 9.1% (2) 22.7% (5) 22.7% (5) 13.6% (3)
44.0% (11) 20.0% (5) 4.0% (1) 16.0% (4) 4.0% (1)
21.2% (7) 9.1% (3) 0.0% (0) 24.2% (8) 3.0% (1)
0.0% (0) 0.0% (0) 16.7% (1) 0.0% (0) 0.0% (0)
68.2% (15) 4.5% (1) 23.6 15.0; 17 (7–51) 4.8 8.4; 2 (1–38)
16.0% (4) 8.0% (2) 22.2 18.9; 16 (2–73) 4.7 6.5; 2 (1–25)
0.0% (0) 0.0% (0) 18.6 9.8; 17 (1–49) 3.6 5.2; 3 (1–23)
0.0% (0) 0.0% (0) 14.5 4.8; 16 (8–21) 2.2 3.6; 1 (1–9)
Adjusted p 0.003* 0.417 0.016* 0.524 0.328 <0.001* 0.393 0.736 0.391
The p-values were derived from multivariable analysis for ICU LOS and HLOS; and from bivariate analysis for complications and mortality. The p-values were obtained after adjustment for MESS scores. AKA, above knee amputation; BKA, below knee amputation; HLOS, hospital length of stay; ICU, intensive care unit. * p-Values are significantly different (p < 0.05).
Please cite this article in press as: Branco BC, et al. The predictive value of multidetector CTA on outcomes in patients with below-theknee vascular injury. Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.001
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JINJ-6239; No. of Pages 7 6
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Fig. 3. Primary outcomes according to the number of patent vessels to the foot: (a) below-the-knee compartment syndrome requiring fasciotomy; (b) major amputation (AKA or BKA).
retrospective, single-center study of the topic, however, Dua et al. [17] identified a significant failure rate associated with this approach. In their small series of 36 patients with trifurcation outflow injuries identified by CTA, they noted that patients with single-vessel outflow on imaging failed observation in 37.5%. Our presently reported multicenter results support this finding. We noted that 56% of patients with only single vessel outflow identified on extremity CTA required operative intervention. As with the findings of Dua et al. [17], we noted a stepwise relationship between the number of patent uninjured vessels identified on CTA and subsequent successful nonoperative observation. When considering our present results, it is important to note that successful limb salvage remains a complex issue that is not entirely dictated by the presence or degree of vascular injury alone. Several groups have previously conducted thoughtful, multicenter examinations designed to develop effective criteria for predicting outcome after severe lower extremity injury, with disappointing results [20–22]. The interplay of factors requiring consideration, including nerve, soft tissue, bony and vascular elements of injury, require careful multidisciplinary collaboration [23]. It is the hope, however, that our present results will contribute to an improved understanding of the risk to the injured limb relative to the vascular elements of consideration. The ultimate goal of vascular limb salvage remains the restoration or preservation of adequate perfusion to the distal limb/foot to support healing and functional requirements. The assessment of vascular limb salvage relies on a thoughtful evaluation beginning with initial clinical exam/ABI assessment and appropriate utilization of CTA or angiography to identify and triage vascular injury. Additional objective assessments may also be of important clinical utility, including the use of toe pressures by plethysmography or other advanced assessments to determine the adequacy of distal perfusion. It is important to note that almost half of the patients in our study with single-vessel run-off to the foot had limb salvage without the use of tibial revascularization using a variety of individualised assessment approaches. The utility of these adjuncts in single-vessel run-off has not been well studied in a multi-institutional fashion and requires additional study. Similarly, the outcome associated with revascularization of
single-vessel run-off in the injured limb requires additional investigation. Our study has several important limitations that must be recognised. The retrospective design precluded the effective capture of key information, including initial bedside ankle-brachial index assessment and other granularities of the physical exam that may be important in guiding the decision for both CTA evaluation and subsequent operative intervention. There is also likely a significant selection bias to the use of CTA relative to injured extremities in our series. Patients with severe soft tissue or bony injuries may have been taken directly to the operative theater for more expedient intervention, thereby bypassing CTA in favour of intraoperative Doppler ultrasound or traditional angiographic evaluation. While we were able to identify the individual elements of the MESS score through registry and chart review (Table 1), the heterogeneous nature of these injuries compromises our ability to precisely comment on the impact of individual injury elements in dictating the need for subsequent operative intervention. In addition, some defined complications were abstracted from the trauma registries of the respective study institutions. The criteria utilised to define these specific complications, most notably that of Acute Kidney Injury (AKI), while consistent to each specific registry, may have changed over time and differ slightly between centers. The ability to link to source data beyond registry variables for these definitions was limited due to the retrospective nature of our study. Finally, our study only recorded initial hospitalization outcomes. We cannot, therefore, comment on subsequent postdischarge functional outcomes of the patients identified. Patients with dense nerve injuries are left with a viable extremity that is functionless. While they initially refuse amputation, it is our experience that these patients often return to request an elective amputation many months after their injury. Conclusion We hope this multicenter study provides additional insight into the utility of CTA evaluation of the injured distal lower extremity. While significant additional study is required, our present effort provides evidence that the number of patent trifurcation outflow vessels on CTA correlates with subsequent need for intervention. We hope that this information can be utilised in the multidisciplinary evaluation of the injured extremity to guide informed decisions regarding intervention, including the need for revascularization of distal outflow vessels to the lower extremity. Conflicts of interest The authors declare that there are no conflicts of interest or disclosures of any kind to report in regard to this manuscript. References [1] Peng PD, Spain DA, Tataira M, Hellinger JC, Rubin GD, Brundage SI. CT angiography effectively evaluates extremity vascular trauma. Am Surg 2008 Feb;74(2):103–7. [2] Inaba K, Potzman J, Munera F, McKenney M, Munoz R, Rivas L, et al. Multi-slice CT angiography for arterial evaluation in the injured lower extremity. J Trauma 2006;60(Mar (3)):502–6 [discussion 506–507]. [3] Inaba K, Branco B, Reddy S, Park JJ, Green D, Plurad D, et al. Prospective evaluation of multidetector computed tomography for extremity vascular trauma. J Trauma 2011;70(Apr (4)):808–15. [4] Rieger M, Mallhoui A, Tauscher T, Lutz M, Jaschke WR. Traumatic arterial injuries to the extremities: initial evaluation with MDCT angiography. AJR Am J Roentgenol 2006;186(Mar (3)):656–64. [5] Busquets AR, Acosta JA, Colon E, Alejandro KV, Rodriguez P. Helical computed tomographic angiography for the diagnosis of traumatic arterial injuries of the extremities. J Trauma 2004;56(Mar (3)):625–8. [6] Soto JA, Munera F, Cardoso N, Guarin O, Medina S. Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities. J Comput Assist Tomogr 1999;23(Mar–Apr (2)):188–96.
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Please cite this article in press as: Branco BC, et al. The predictive value of multidetector CTA on outcomes in patients with below-theknee vascular injury. Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.001