Abstract
Background: Intra-abdominal vascular injury (IAVI) is uncommon but continues to be associated with high mortality rates despite technological advances in the past decades. In light of these ongoing developments, we reviewed our contemporary experience with IAVI in an attempt to clarify and refine our management strategies and the outcome of these patients.
Methods: We retrospectively reviewed the charts of all patients admitted between January 2011 and December 2014 at a major trauma centre in South Africa who were found to have an IAVI during laparotomy for trauma. We collected demographic and clinical data including mechanism of injury, location and severity of the injury, concurrent injuries, physiologic parameters and clinical outcome.
Results: We identified 110 patients with IAVIs, of whom 98 had sustained penetrating injuries (55 gunshot wounds and 43 stab wounds). There were 84 arterial injuries (including 21 renal and 17 mesenteric) and 74 venous injuries (including 21 renal and 17 inferior vena caval). Combined venous and arterial injuries were found in almost one-third of patients (34 [30.9%]). Fifty-seven patients (51.8%) required intensive care admission. The overall mortality rate was 28.2% (31 patients); the rate was 62% for aortic injuries and 47% for inferior vena cava injuries. Liver injury, large bowel injury, splenic injury and elevated lactate level were all associated with a statistically significantly higher mortality rate.
Conclusion: The mortality rate for IAVI remains high despite decades of operative experience in high-volume centres. Open operative techniques alone are unlikely to achieve further reduction in mortality rates. Integration of endovascular techniques may provide an alternative strategy to improve outcomes.
Much has been published about intra-abdominal vascular injury (IAVI) over the last 60 years. Most of these publications were retrospective; very few were documented large case series. The persistent theme throughout is that the management of IAVI is challenging and that mortality rates are high. Accessing the injured vessels may be difficult, and patients are often in a physiologically compromised state. In addition, competing priorities and concomitant intraabdominal contamination restrict the options for vascular repair.1
The surgical response to these taxing injuries has been multifaceted. The initial approach was to perfect the surgical exposure and to debate the optimal operative techniques to manage these injuries.2,3 Although standardizing these surgical lessons was important, it has become apparent that there is a natural limit to the extent to which improved operative techniques alone can further improve outcome. There has been much recent focus on imaging techniques, perioperative resuscitation, aggressive replacement of blood products and damage-control strategies. However, the mortality rate has not been substantially reduced over the last 2 decades (37% in 1975–1980 v. 33% in 2004–2009).4–6 It is accepted that exsanguination eclipses coagulopathy as the primary cause of death in IAVI, with 1 study showing that only 24% of the deaths from uncontrollable hemorrhage were attributable to some form of coagulopathy.6 Controlling exsanguination is therefore the single most important objective if one hopes to avoid death in these patients, yet controlling bleeding in these cases remains a challenge. The most recent military reports suggest that the next evolution in the management of these exsanguinating injuries will be a combination of surgical and endovascular-based modalities.7,8
In light of these ongoing developments, we reviewed our contemporary experience with IAVI to attempt to clarify and refine our management strategies and the outcome of these patients.
Methods
We retrospectively reviewed the charts of all patients admitted between January 2011 and December 2014 through the Pietermaritzburg Metropolitan Trauma Service, Pietermaritzburg, South Africa, who were found to have an IAVI during laparotomy for trauma. The data collected included sex, age, mechanism of injury, location and severity of the injury, and admission physiologic parameters, including lactate level. All abdominal vascular injuries were graded with the American Association for the Surgery of Trauma Organ Injury Scale (AAST-OIS) for abdominal vascular injury9 (Table 1). Other data collected included any concomitant solid-organ injury, duration of hospital stay, admission to the intensive care unit (ICU) and end mortality. Ethics approval for this study and for maintenance of the register was obtained from the Biomedical Research Ethics Committee of the University of KwaZulu-Natal.
Clinical setting
The Pietermaritzburg Metropolitan Trauma Service provides definitive trauma care to the city of Pietermaritzburg, the capital of KwaZulu-Natal province. It also serves as the trauma referral centre for 19 other provincial hospitals within the province. The service manages a high volume of trauma cases. It is pertinent to note the logistical challenges of prehospital medicine in this setting. Much of the catchment areas is rural, and the transfer time to hospital is often much greater than in the European or North American setting. Many patients whose condition is unstable die even before admission to hospital or access to prehospital medicine.
Injury management
The potential for an IAVI exists in all cases of penetrating torso trauma, and a systematic approach is required in this situation. Important clues to the presence of such an injury include the physiologic state of the patient on presentation and the path of the projectile. Patients with penetrating torso trauma whose condition is unstable are expedited to the operating room. In patients whose condition is stable, imaging may be used selectively, and treatment can be individualized according to the findings. At laparotomy a systematic approach is essential. Four-quadrant packing is used to control active bleeding, soiling is mopped up and the bowel eviscerated, and enteric leakage is controlled with packs. Damage-control techniques are implemented, and there is no place in this cohort of patients for prolonged definitive management of enteric injuries.
The management of the IAVI follows standard guidelines. If a large central hematoma is recognized, proximal control of the aorta at the hiatus is recommended before the hematoma is explored. If a suprarenal injury is suspected, a combined left and right medial visceral rotation is required to expose this part of the aorta. If the injury is believed to be infrarenal, a right rotation usually suffices. Lateral hematomas are not explored unless there is active bleeding or rapid expansion. Pelvic hematomas are explored selectively. The path of the projectile is delineated to make sure it is away from any major vessels in the pelvis. All nonessential vessels are ligated. Simple venous injuries are repaired and complex ones ligated. Essential arterial injuries are managed with primary repair if possible; if this is not possible, more complex individual solutions are used, including temporary shunting and the use of interposition grafting or extra-anatomic bypass. The primary concern is always the physiologic status of the patient, and this dictates management.
Statistical analysis
Data are reported as mean or median values for continuous variables and proportions for categorical variables. We used the nonparametric Kruskal–Wallis test to assess differences in presenting heart rate, systolic blood pressure and lactate level dependent on AAST-OIS grade. We assessed categorical variables using the χ2 test. We used a post hoc Dunn test to assess differences between groups.
We assessed concurrent organ injuries and examined their relation with mortality and ICU admission using χ2 analysis. The 4 most common organ injuries and the single physiologic parameter most associated with death were included in a multiple logistic regression analysis. The dependent variable was death. The statistical significance level was accepted as 0.05 for all analyses. All statistical analysis was performed with the use of R 3.3.3 software (R Foundation).
Results
During the study period, 1283 patients underwent laparotomy for trauma, of whom 110 (8.6%) were found to have an IAVI. Ninety patients (81.8%) were male, and the mean age was 29 years (Table 2). Of the 110 injuries, 98 (89.1%) were penetrating trauma, and 12 (10.9%) were blunt. Of the 98 penetrating trauma cases, 55 were gunshot wounds and 43 were stab wounds. The mean admission physiologic parameters were heart rate 105 beats/min, systolic blood pressure 102 mm Hg and serum lactate level 5 mmol/L.
Arterial injuries
There were 84 arterial injuries in total: renal (21), mesenteric (17), aortic (8), external iliac (7), superior mesenteric (6), inferior mesenteric (6), common iliac (5), splenic (5), hepatic (2), internal iliac (2), sigmoid (2) and, in 1 case each, gonadal, omental and pancreaticoduodenal. Table 3 summarizes the patients’ clinical characteristics by AAST-OIS grade. There was a significant difference in heart rate and systolic blood pressure across grade I–IV injuries. The post hoc Dunn analysis revealed this difference to be significant between grade I versus grade III (p < 0.001) and between grade III versus grade IV (p = 0.006) for systolic blood pressure, and between grade I versus grade IV (p = 0.02) for heart rate (Table 4).
The management strategies used in the patients with arterial injuries are summarized in Table 5. Aortic injury was associated with the highest mortality rate, 62%.
Venous injuries
Seventy-four venous injuries were identified: renal (21), inferior vena cava (17), common iliac (11), external iliac (6), internal iliac (4), superior mesenteric (4), inferior mesenteric (3), gonadal (3), portal (2), pelvic (2) and hepatic (1). Of the 17 inferior vena cava injuries, 9 were infrarenal. Table 6 summarizes the patients’ outcome by AAST-OIS grade. There was no significant difference in rates of death or ICU admission across AAST-OIS grade for all venous injuries.
The management strategies used in the patients with venous injuries are summarized in Table 7. Inferior vena cava injuries had the highest mortality rate, 47%; in most cases (13) of inferior vena cava injury, the patient underwent primary repair.
Arterial and venous injury combined
Combined venous and arterial injuries were found in 34 patients, of whom 11 (32%) died and 21 (62%) were admitted to the ICU.
Concurrent injuries
Concurrent nonvascular injuries were as follows: small bowel (63), large bowel (33), liver (33), kidney (32), stomach (22), pancreas (19), diaphragm (12), duodenum (10), spleen (10), bladder (7) and ureter (4) (Table 8). The injuries associated with the highest mortality rates were of the spleen (60%, p = 0.02) stomach (50%, p = 0.01) duodenum (50%, p = 0.1) and liver (45%, p = 0.008); the lowest mortality rates were associated with ureteric (25%) and renal (25%) injuries. The 4 organ injuries most strongly suggestive of death on the χ2 test and the physiologic parameter most associated with death (lactate level, Table 9) were included in a multiple logistic regression analysis. Liver injury, large bowel injury, splenic injury and elevated lactate level were all associated with a statistically significantly higher mortality rate (Table 10).
Clinical outcome
Fifty-seven patients (51.8%) required admission to the ICU. Thirty-one patients (28.2%) died; causes included renal dysfunction (25 patients), respiratory (6), intra-abdominal sepsis (4), wound sepsis (4), cardiac (3) and neurologic (3). The remaining patients did not require an ICU stay and had an uneventful postoperative recovery. All 4 patients who had vascular grafts had associated enteric injury. One of these patients, who had a destructive external iliac artery injury, had a prosthetic graft to restore continuity. Graft sepsis and graft failure developed, and the patient ultimately died due to hemorrhage from a septic false aneurysm.
Discussion
Numerous reports over the past half-century have reiterated that IAVIs are associated with a high mortality rate. Our findings suggest that this remains the case. Controlling exsanguination is key to achieving a reduction in death rates following IAVIs, and this represents an ongoing surgical challenge. The methods of surgical ligation and repair, which were pioneered in the military conflicts of the mid to late 20th century, have remained largely unchanged.
Repair remains the only feasible option in aortic injuries; aortic ligation is almost universally fatal.10 In this cohort of patients, after aortic injury, the highest mortality rate was found for the hepatic (50%), superior mesenteric (50%) and splenic (40%) arteries. All were managed by ligation apart from 1 injury to the mesenteric artery, which was repaired. Almost all cases of actively bleeding renal artery injuries were managed by nephrectomy. If there is a nonexpanding perirenal hematoma, this should be managed conservatively, as opening Gerota’s fascia generally results in uncontrolled bleeding, which can be dealt with only by nephrectomy. If conservative management is embarked on, endovascular and endo-urological techniques can be used to salvage the situation once the initial operative management is complete.
Inferior vena cava injuries remain highly lethal, as evidenced by our mortality rate of 47%. Although primary repair was the most commonly used approach in our study, ligation is increasingly applied, especially for infrarenal caval injuries.11,12 There were 17 inferior vena cava injuries in the current series, 4 of which (3 infrarenal and 1 suprarenal) were ligated. All 4 patients had associated enteric injuries, but all survived. Among the 13 cases of inferior vena cava repair, 8 patients (62%) died, all but 1 of whom had associated enteric injury.
The management of iliac artery injuries is extremely challenging, with most cases in the current series undergoing primary repair. One patient with an external iliac artery injury required a prosthetic interposition graft, and in 1 case a bleeding internal iliac artery injury was embolized. Interposition grafting is used in large-calibre vessels where flow must be preserved and has been reported in aortic, superior mesenteric artery, renal and iliac artery injuries.13–15 Although complex injuries may require an interposition graft, the presence of intra-abdominal sepsis means that these repairs are at high risk for the development of graft sepsis. The consequences of graft failure in this setting are usually catastrophic. The 2 alternatives to an interposition graft are extra-anatomic bypass and a temporary intravascular shunt. However, creating an extra-anatomic bypass is usually not feasible in an injured patient whose condition is unstable. Although the use of temporary intravascular shunts as part of a damage-control strategy has been reported,16 it has not found widespread use at our institution.
Although exsanguination eclipses coagulopathy as the primary cause of death in IAVI, failure to implement adequate resuscitative and damage-control strategies results in dismal outcomes. This was shown by our parent institution, King Edward VIII Hospital, in Durban, where the mortality rate for caval injuries increased from 35.7% to 88% over a 15-year period 2 decades ago. The increase was attributed to the lack of implementation of damage-control techniques in response to a massive increase in devastating gunshot wounds during a period of great political instability.17 Since that period, damage-control approaches to IAVIs have gained widespread acceptance in our environment. Our current mortality rate is in keeping with the international and national literature, no doubt largely due to adoption of damage-control approaches.6
It is unlikely that we are going to achieve further reductions in mortality rates using exclusively open operative techniques. The most recent military reports suggest that the next evolution in the management of IAVIs will likely be endovascular-based modalities.18 The advent of these techniques has expanded the scope for nonoperative approaches to IAVIs. Endovascular approaches can be used to arrest hemorrhage through balloon occlusion or embolization, or to repair an injured vessel with an endovascular graft. Embolization is an endovascular option for injuries to small and medium-sized nonessential vessels.19 In our series, 4 patients underwent embolization (3 of the renal artery and 1 of the inferior internal iliac artery); all survived. Embolization of the internal iliac artery or its branches is generally well tolerated.20 Although not performed in our analysis, successful embolization of superior mesenteric artery injuries has been reported.21 The superior mesenteric artery territory is a particularly attractive area for endovascular intervention as it is difficult to surgically access this area. The development of hybrid operating rooms such as the so-called RAPTOR suite (resuscitation with angiography, percutaneous techniques and operative repair) may allow for more seamless integration of open and endovascular approaches in the management of IAVIs. Currently, there is great interest in resuscitative endovascular balloon occlusion of the aorta.22 This innovation was prompted by the recent military experience, and reports on its use are limited.23 This technique could be instrumental in facilitating proximal control while allowing endovascular intervention in vessels that are difficult to access without recourse to massive retroperitoneal dissections. The exact place of these techniques is yet to be defined.
Limitations
This was a single-centre experience. For a more thorough analysis, a larger study across multiple centres is required.
Conclusion
Despite the standardization of operative approaches and the implementation of damage-control surgery and resuscitation over the last 50 years, the mortality rate for IAVI remains high. Exsanguination remains the most common cause of death. It is hoped that the ongoing development of endovascular techniques and approaches in the management of these injuries may improve outcomes in the future.
Footnotes
Competing interests: None declared.
Contributors: All authors designed the study. R. Weale, V. Kong, V. Manchev, G Laing and J. Bruce acquired the data, which R. Weale, V. Kong, G. Oosthuizen, G. Laing and D. Clarke analyzed. R. Weale and D. Clarke wrote the article, which all authors reviewed and approved for publication.
- Accepted September 5, 2017.