Incidence of postoperative acute renal failure among violence-related cardiovascular trauma patients: a review of our experience in 117 cases

Abstract

Background: The purpose of this retrospective study was to determine the incidence of renal failure and hemodialysis (HD) in postoperative period after cardiovascular surgery associated with trauma. Methods: One hundred and seventeen cases of violence-related cardiovascular trauma patients had emergent surgery between 1996 and 2009. Cases were reviewed in three main groups: Cardiac trauma in 11 patients (Group A), vascular trauma in 78 patients (Group B), and cardiovascular trauma in 28 patients (Group C). Postoperative incidence of HD requirements with acute renal failure (ARF) was investigated in these groups of patients postoperatively. Results: Multiorgan deficiency developed in 10 patients from Group A, in 45 patients from Group B, and in 26 patients from Group C. Overall mortality was 81 cases in 117 patients. Total hospitalization periods were 21 ± 2, 17 ± 3, and 27 ± 1 days for Group A, Group B, and Group C, respectively. HD administrations were indicated in 3 patients in Group A, 41 patients in Group B, and 9 patients in Group C. No statistically significant difference presented in any study parameter between groups. Conclusions: Cardiovascular trauma is a common reason for emergent cardiovascular surgery. Postoperative renal failure occurs among these patients in a wide percentage. We strongly advocate a close and detailed follow-up of renal functions in these patients during the hospitalization period and immediate HD at indication.

Keywords:

• cardiovascular trauma
• emergent surgery
• postoperative renal failure
• hemodialysis
• trauma

INTRODUCTION

In this study, we have retrospectively reviewed the postoperative indications of hemodialysis (HD) in all patients undergoing an emergent cardiovascular surgery for cardiovascular trauma from February 1996 through November 2009 in a single academic institution. With analysis of these retrospective data, we detailed the preoperative, intraoperative, and postoperative parameters and HD incidence.

Trauma is one of the leading etiologies of hospital death, accounting approximately 7000 cases annually in Turkey. Cardiovascular trauma presents a dramatic worse prognosis. Mortality rates differ between 15 and 80% depending on the status of other systems of participation.^1,2 Multidisciplinary approaches are essential in majority of severe cardiovascular trauma cases.

MATERIAL AND METHODS

Initial preoperative evaluation of the cases include blood tests (CBC, electrolytes, renal and liver functions, blood type definition, coagulation profile, serology for Hepatitis and HIV), EKG, X-ray studies of cervical region, chest, abdomen and extremities, Doppler US, CT, and MRI investigations with indications. Endoscopic procedures and angiographies may only be administered for patients with stable conditions. Acute renal failure (ARF) conditions in our patients mostly required acute HD. Our indications for HD are summarized as below.

• Creatinine clearance levels less than 20–25 mL/min/1.73 m² and creatinine levels over 12 mg/dL

• Symptoms of uremia: nausea, vomiting, mental degradation, seizure, progressive volume overload

• Severe metabolic acidosis with oliguria/anuria

• Blood urea nitrogen (BUN) levels over 70–100 mg/dL with renal dysfunction

• Acute pericarditis with serious pericardial effusion

• Hyperkalemia with acidosis

• Severe metabolic alkalosis

• Clinical situations with suspicious toxicity caused by medications

• Resistant hypothermia

One hundred and seventeen patients with acute cardiovascular injury related to violence acts were included in this study. Our study group's mean age was 31 (range, 6–78). Male to female ratio was 96 to 21. Patients were divided into three main groups: Group A, Group B, and Group C. Group A consisted of isolated cardiac injuries (n = 11), Group B for isolated vascular trauma (n = 78), and Group C (n = 28) cases were with cardiac and vascular injuries together. These patients presented concomitant morbidities in other organ systems such as skeletal, pulmonary, gastrointestinal, and/or neural systems with cardiovascular system. Preoperative data is summarized for each group in Table 1. Cause of cardiovascular trauma was fire-arms in 28 cases, stab wounds in 80 cases, and fire-arms with concomitant stab wounds at the same time in nine patients. Percentage of distribution for trauma causes for each group is also summarized in Table 1. Statistically significant difference was not observed between three groups on any preoperative data (p > 0.05).

TABLE 1.  Descriptive preoperative patient characteristics

Variable	Group A (n = 11)	Group B (n = 78)	Group C (n = 28)	Total (n = 117)	p-Value
Age (years)	30 ± 8.2 (range, 11–64)	26 ± 9.4 (range, 6–67)	33 ± 9.1 (range, 14–78)	31 ± 10.5 (range, 6–78)	p > 0.05
Male/female	9/2	65/13	22/6	96/21	p > 0.05
Fire-arm/stab ratio	0/9	12/62	16/9	28/80	p > 0.05
Fire-arm and stab injury	2	4	3	9	p > 0.05
Preoperative CPR	4	4	6	14	p > 0.05

Note: CPR, cardiopulmonary resuscitation.

RESULTS

There were no statistically significant difference in values and postoperative measures of operation and intubation time, blood and blood-product utilization, cardiovascular intensive care unit, and total hospitalization time. The sum of this data is showed in Table 2. Statistically significant difference was not observed between three groups on any postoperative data mentioned in Table 2 (p > 0.05).

TABLE 2.  Descriptive operative patient characteristics

Variable	Group A (n = 11)	Group B (n = 78)	Group C (n = 28)	Mean (n = 117)	p-Value
OT	6 ± 4.1	7 ± 2.5	7 ± 1.2	6 ± 9.6	p > 0.05
ET	32 ± 8	17 ± 2	30 ± 8	26 ± 6	p > 0.05
ICUT	12 ± 1.5	8 ± 1.4	17 ± 0.4	14 ± 8.5	p > 0.05
HT	21 ± 2	17 ± 3	27 ± 1	20 ± 6	p > 0.05
BPU	29 ± 3	28 ± 2.4	37 ± 1.1	28 ± 8.4	p > 0.05

Note: OT, operation time (hours), ET, intubation time (hours); ICUT, intensive care unit time (days); HT, hospitalization time (days); BPU, blood and blood-product utilization (number of blood-product units for erythrocytes suspension and fresh frozen plasma).

Overall mortality was observed in 81 cases in early and late postoperative periods. Table 3 presents the detailed mortality in all groups with differentiation of postoperative periods. Early operative mortality was defined as deaths in the first 24 h. Discharged patients were defined in two paths: discharged to home and to another clinic such as general surgery, orthopedic, plastic and reconstructive surgery, nephrology. Statistically significant difference was not observed between three groups on mortality rates shown in Table 3 (p > 0.05). Details of surgery for Group B and Group C are summarized in Table 4 with characteristics of amputation rates, prosthetic/autologous grafts or primary reparation, and/or patch-plasty and fasciotomies. Statistically significant difference was not observed on any data between two groups shown in Table 4 (p > 0.05).

TABLE 3.  Descriptive postoperative mortality characteristics

Variable	Group A (n = 11)	Group B (n = 78)	Group C (n = 28)	Total (n = 117)	p-Value
Operative	3	7	12	22	p > 0.05
Early postoperative	4	19	10	33	p > 0.05
Late postoperative	3	19	4	26	p > 0.05
Discharge	1	33	2	36	p > 0.05

TABLE 4.  Vascular surgery technique variation, amputation rate, and fasciotomies in Groups B and C

Variable	Group B (n = 78)	Group C (n = 28)	Total (n = 106)	p-Value
Amputation	19	6	25	p > 0.05
Fasciotomy	58	22	80	p > 0.05
PTFE graft	24	6	30	p > 0.05
VSM graft	41	19	60	p > 0.05
Primary repair	11	3	14	p > 0.05
Patchplasty	2	0	2	p > 0.05

Note: PTFE, polytetrafluoroethylene; VSM, vena saphena magna.

Renal functions were screened twice a day for all patients during ICU period and once a day in cardiovascular surgery department. All patients presented a significant elevation on creatinine and BUN levels during the first three postoperative days. Afterwards, in 64 patients renal function test responded to certain treatment strategies. Nevertheless, these patients' renal functions did not return to baseline values, meaning a slight permanent increase. Acute HD indications with ARF presented in 53 cases. Details of these data are summarized in Table 5. Persistent ARF with HD necessity appeared in 25 patients in total.

TABLE 5.  Descriptive postoperative ARF and HD characteristics

Variable	Group A (n = 11)	Group B (n = 78)	Group C (n = 28)	Total (n = 117)
HD	3	41	9	53
PARF	1	22	2	25
Death ratio	2/3	13/41	8/9	24/53

Notes: HD, hemodialysis; PARF, persistent acute renal failure.

Death ratio is defined as number of deaths in this group of patients with HD indication.

Mean creatinine levels in the first 20 postoperative days are summarized in two groups in Figure 1: HD (HD indicated group of patients, n = 53) and non-HD (patients with moderate renal functional decrease without any indications for HD, n = 64). Deaths in postoperative period were also projected on this figure with their results of creatinine levels during their ICU follow-up.

FIGURE 1. Mean creatinine levels and postoperative alterations following surgery.

STATISTICAL ANALYSIS

All of our numerical data were presented as mean ± SD. In indication, Student's t-test and Mann–Whitney tests were used to assess differences between groups for statistical significance. A value of p < 0.05 was accepted as statistically significant.

COMMENT

Cardiovascular trauma may be categorized as blunt and penetrating trauma. Penetrating injury is often occurring with a stabbing wound and/or a firearm injury. Death incidence is relatively high in this clinical feature. Recently, improved prehospital and perioperative care are beneficial for potentially salvageable patients of trauma, but death and severe complications still take part in a wide range of statistics. Cardiovascular injury may be divided into three main regions: thoracic, abdominal, and peripheral trauma.

Clinical consequences mostly arising from chest trauma are severe and related to early period deaths. Presentation of hemodynamic arrest with clinical shock is not rare. Volume replenishment is essential for preoperative evaluation. A resuscitative thoracotomy frequently raises the survival rates in these patients. In detailed prevalence of thoracic trauma, lung injuries and contusions in 60–70%, trachea-bronchial injuries in 75–80% with airway obstruction, esophageal trauma in 1%, diaphragmatic injury in 15–46%, great vessel lacerations in 0.3 to 10% including aortic trans-section, cardiac injuries, and commotion cordis with fatality rates of 70–80% (right ventricle 43%, left ventricle 34%, right atrium 16%, and left atrium 7% of cases) may occur.^3–5 Possible complications include sudden death, retained pulmonary foreign bodies, pulmonary hematoma, chest wall hernia, lung cysts, systemic air embolism, tracheoesophageal fistula, broncho-pleural fistula, empyema, pneumonia, cardiovascular fistula, and chylothorax.^6,7 Thoracic trauma may include a neck trauma with a multitude localization of organs which augments the imminent mortality. Thoracic trauma is by a majority a reason of non-survival status despite the intense effort of staff perioperatively.

Abdominal vessel injuries are observed in 5–30% of all vascular injuries.^8,9 In contrast to thoracic injuries, abdominal penetrating vascular injuries are more uncommon but highly lethal. Intra-abdominal-vascular injuries are with hemorrhage in rapid blood loss. American Association for Surgery of Trauma notification in Injury Scale for vascular injuries (AAST-OIS) may be a guide to approach abdominal vascular cases. Incidence of intra-abdominal-vascular injury is 10–15% for stab wounds and 20–25% for firearms.¹⁰ Nearly all cases are with visceral injuries. Thus, a patient always requires a multidisciplinary evaluation. Patients with hemorrhagic shock present a metabolic acidosis status, coagulopathy, and hypothermia. Furthermore, postoperative results are more likely to be effected negatively from myelonephropathic-metabolic syndrome with reperfusion injury, ARF with renal trauma and/or massive transfusions, peritonitis, multiorgan dysfunction, wound dehiscence, systemic infection, abdominal compartment syndrome, respiratory complications. Overall mortality rates are 60% for suprarenal aorta injuries, 40–80% for superior mesenteric artery injuries, 100% for vena cava inferior trauma with suprarenal aorta, 50% for infra-renal aorta injuries, and 15% for iliac artery injuries.¹¹

Extremity vascular traumas are relatively more frequent than thoracic traumas with major and/or minor vessels injuries. Upper extremity vascular injuries alone take part in 30–50% of all extremity vascular traumas. In this group, brachial artery seems to be most susceptible as in 15–30% of cases. Other upper extremity arteries involve in the incidence rates of 5–10% for axillary artery and 5–30% for forearm vessels.¹² For the lower extremities, the predominant cause for injury is especially penetrating wounds. Iatrogenic reasons are also not rare between these patients. Patients with lower extremity vascular injury typically present with arterial and venous trauma together. Stab wounds with bone involvement are extremely rare. Fractured long bones of the lower extremity and dislocated joints frequently increase the overall risk of trauma. On the other hand fire-arm injuries are mostly with collateral damage including neighboring bone and soft tissue with nerves. Rupture of the vessels can be partial or complete and is relatively uncommon to administer an only-medical therapy for these group of patients.

Preoperation of blood and blood products is essential as a preoperative step. In all vascular reconstructive surgery indications, a 3-h preoperative period is the mostly accepted time limit for the best postoperative results. Prognosis of the extremity depends on the intravascular volume, surgery time, regional vessel anatomy, collateral possibilities, and intensive postoperative monitorization. Autologous vein reconstructions are the first choice for better postoperative results but cases with unstable hemodynamic status may receive a polytetrafluoroethylene (PTFE) graft. Some recent authors advocate an endovascular treatment for selected patients.¹³ In most of the cases with emergency, venous traumas are mostly primarily ligated.

During the postoperative period a number of catastrophic scenarios may occur: amputation, reperfusion damage with a wide range of clinical presentations, and compartment syndrome. Prolonged preoperative period is a major reason for extremity losses. The Mangled extremity severity score (MESS) should be considered as a source to identify the amputation risk.¹⁴ Values more than 7 are a strong indicator for amputation. De Bakey¹⁵ reported amputation rates greater than 40% in all cases with vascular surgery during the World War II. On the contrary, Rich et al.¹⁶ reported a rate of 15% depending on the statistics of Korean War. Fasciotomy with an enhanced risk of infection and fluid loss may be beneficial against tissue gangrene or extremity loss. On the other side, renal failure occurs because of myoglobin release as a part of myelonephropathic-metabolic syndrome.¹⁷ Vascular injuries are mostly complicated with concurrent bone, nerve, and soft tissue with muscle trauma. Other postoperative complications include ARF with necessity of HD, graft thrombosis, systemic infections, multiorgan insufficiency, motor or sensory nerve deficits, tissue necrosis, and arterio-venous fistulas and/or aneurysms; restricting the overall survival between 8 and 65%.

Postoperative renal failure is a common risk among these patients with cardiovascular injury. ARF is an acute decline in renal function with acute elevations in plasma BUN and serum creatinine. In ARF, an increase of serum creatinine occurs in a percentage of 50 which characterizes a severe reduction of urine output with oliguria less than 0.5 mL/Kg/hr or anuria in a longer period than 6 hours with an increase in serum creatinine more than 0.5 mg/dL from the baseline. The causes of ARF are conventionally reviewed into three groups: prerenal, renal, and postrenal. Cardiovascular trauma patients may present all these conditions together or alone. Severe hypovolemia and cardiac dysfunction are with prerenal ARF, and postrenal trauma of anatomic structures of urinary tract can be considered with a reason of postrenal ARF. Renal ARF reasons are renal and relevant vascular trauma, massive blood and blood-product perfusions, perioperative nephrotoxic medications and myelonephropathic-metabolic syndrome. Among these scenarios, an acute tubular necrosis (ATN) seems to be the most frequent reason for ARF. ARF may result in four end-points: death, recovery, persistent ARF (complete loss of renal function for 4 weeks), and end-stage kidney disease (complete loss of renal function for more than 3 months). Postoperative medications including aminoglycosides, amphotericin B, radiographic contrast media, cyclosporine and tacrolimus, cisplatin, ifosfamide, foscarnet, and pentamidine have been also shown to cause ARF.

In these trauma patients, myelonephropathic-metabolic syndrome is a result of rhabdomyolysis and chain reactions of reperfusion after cardiovascular surgery. Rhabdomyolysis is first described by the victims of crush injury in 1940–1941 in London with World War II bombings. In a severe trauma situation toxic cellular content and free oxygen radical's leakage into the systemic circulation from muscle fibers and reperfused tissue result in several clinical consequences with a reduced renal function.¹⁸ Myelonephropathic-metabolic syndrome for a trauma patient may cause and may be caused by hypovolemia, hyperkalemia, metabolic acidosis, disseminated intravascular coagulation, and ARF. In these patients, a serum creatine kinase test can be performed with 100% sensitivity. A serum peak with 3–10 times from the baseline typically presents a diagnose. Also an elevation for aldolase, lactate dehydrogenase, and glutamic axaloacetic transaminase may be found as nonspecific enzyme markers.

After cardiovascular surgery, renal dysfunction incidence may decrease with appropriate fluid resuscitation and rapid evaluation. Mortality associated with ARF is high and varies between 10 and 80% of trauma cases. In the medical literature on this topic, ARF incidence as a complication of surgery is reported in 29–34%.^19–21 In our study group ARF occurred in 53 cases of 117 patients with a ratio of 54% which was significantly higher. Reasons of this elevation of ARF ratio in our study is considered to be caused by the prolonged duration between trauma and operation according to the transport period. A suprarenal cross clamp may be applied for 40 min safely but longer periods are reported to be with worsened renal functions. Twenty-four patients died after surgery in this HD group in a rate of 45%, which points almost half of the patients. In our opinion, ARF is a component of multi-organ dysfunction (MOD).

Uppermost attention and treatment is mandatory against reduced renal functions in cardiovascular surgery with adequate fluid resuscitation, limited ischemic periods for kidneys during surgery, avoidance of renally toxic medications and prevention of hypotensive postoperative status.

STUDY LIMITATIONS

Our study data derived were from a limited quantity of patients due to high mortality rates of cardiovascular trauma prior to administrations to the emergency department in our hospital region. Our data cannot definitely establish an etiologic link between the presence of ARF and certain complicated clinical status. ARF was assumed to be multifocal. We were also not able to gather data of preoperative renal functions of patients to determine an unknown kidney failure as in a mild chronic renal dysfunction in most cases. Preoperative reduced renal functions may clearly affect the incidence and severity of postoperative ARF. Likewise, postoperative early deaths according to patients' severe clinical situation and multiorgan dysfunction, HD incidence rates may be affected with short follow-ups. Because of these early deaths, a HD application was not a matter of choice. The fact that HD indications were so similar between groups suggests that any such misclassification about renal functions was minor. On the other hand, larger series may represent a keener result with more detailed data. Long-term follow-ups also were not recorded after discharges. Furthermore, iatrogenic trauma and non-violence causes such as high-velocity vehicle accidents and/or occupational multitrauma cases were excluded from the study.

CONCLUSION

Cardiovascular trauma is a common reason for emergent cardiovascular surgery. Postoperative renal failure is not rare and occurs among these patients in a wide percentage by a relationship with severe hypotension periods, myelonephropathic-metabolic syndrome, and concurrent urinary system injury, and massive blood, blood-product transfusions, and as a complication of surgical maneuvers. Renal failures strengthen the risk of mortality depending on the fact that ARF is a component of postoperative multiorgan deficiency. HD applications are life-saving procedures and essential in treatment algorithm after surgery. We strongly advocate a close and detailed follow-up of renal functions in these patients during the hospitalization period and immediate dialysis at indication.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.