The Efficacy of Salvage Intervention with Emergency Transient External Arterial Bypass for Traumatic Artery Occlusion of Main Extremities.

Even if the vascular repair is successful, the frequency of limb loss is still high when popliteal artery injury is associated with postischemic syndrome due to blunt trauma or a prolonged ischemic time. Because prolonged ischemia interferes with an injured foot rescue, shortening of the ischemic time is a major aim of surgeons. We present two types of transient external arterial bypass and two cases of ischemic extremities due to main arterial injury. Even though the injured extremities had no circulation for more than 6 h, a transient external arterial bypass supplied circulation immediately, and they were reconstructed successfully. Although transient external arterial bypass is a dated technique, it is a recommended option, especially in the management of acute traumatic ischemia of the extremities to shorten the ischemic time and provide immediate reperfusion, which will bring the opportunity to save the ischemic limbs. Copyright:

INTRODUCTION

Although the management of vascular trauma has undergone marked refinement during the past 20 years, it still results in high rates of amputation and remains challenging.[1]

Acute arterial occlusion is a disease in which not only the limbs but also the prognosis of life is poor without prompt diagnosis and appropriate treatment.[2]

Downs and MacDonald evaluated 58 patients who had popliteal artery injuries and underwent arterial repair and concluded that 13 (22%) required amputation. Among them, all legs of 19 patients who were treated within 6 h after injury were salvaged.[3] Banderker et al. reviewed 136 patients with popliteal artery injuries and reported that the most significant factors associated with the high amputation rate of 37.5% were an ischemic time longer than 7 h and the presence of compartment syndrome.[4] These reports suggest that the ischemic time is critical for limb salvage.

In this article, we present two types of immediate transient external arterial bypass technique to shorten the ischemic time for the treatment of patients with acute traumatic main extremity artery occlusion.

Surgical procedure of transient external arterial bypass technique

The transient external arterial bypass system consists of two plastic intravenous cannulae (20-gauge: diameter 1.1 mm, length 51 mm, Terumo C. C.) and a polyvinyl extension tube (length 30 cm, Terumo C. C) as the infusion line. These are all common intravenous line devices that are always available in operating and emergency rooms. Each plastic intravenous cannula is connected to both ends of the extension tube.

In the transient local arterial bypass technique, each plastic intravenous cannula is inserted into a healthy part of the artery on either side of the injury. The cannula is sewn and fixed to the adventitia of the artery with nylon thread to prevent it from coming off [Figure 1b and c]. On the other hand, in the limb shunt technique, each intravenous cannula is inserted into the peripheral arteries of the injured limb and the arteries of the healthy limb. The cannula is taped to the skin like a regular arterial line [Figure 2b and c]. To prevent clotting within the circuit, unfractionated heparin (500 IU) are given by intravenous injection first, and then 500 IU were continuously infused per hour for systemic heparinization.[5] Both methods are as simple as inserting a cannula into the artery, so bypass setup can be completed in about 5 min. Immediately after inserting the bypass, it can be confirmed that the artery flows into the ischemic limb through the extension tube, and after a while, the venous return from the ischemic limb can also be confirmed.

Figure 1

(a) Case 1. Contrast-enhanced computed tomography showed that circulation of the left lower leg had ceased due to occlusion of the popliteal artery (arrow). The picture shows that the patient sustained crush and laceration to the left knee. (b) Intra-operative view showing the patient undergoing transient external arterial bypass. (c) Schematic illustration of the transient external arterial bypass system. (d) Contrast-enhanced computed tomography 9 days after surgery revealed favorable popliteal arterial flow and lower leg circulation

Figure 2

(a) Case 2. Contrast-enhanced computed tomography showed that circulation of the left forearm had ceased due to occlusion of the brachial artery (arrow). (b) The picture shows the patient undergoing limb shunt. The circulation was supplied from dorsalis pedis artery to the forearm through the limb shunt. (c) Schematic illustration shows the circulation to the forearm from dorsalis pedis artery through the limb shunt. (d) Contrast-enhanced computed tomography 7 days after surgery revealed favorable popliteal arterial flow and lower leg circulation

As the arterial flow goes through the bypass, reconstruction of the occluded artery, such as embolectomy and vein graft, can be performed while maintaining distal blood flow.

CASE REPORTS

Case 1. Transient local arterial bypass technique

A 45-year-old male had a traffic accident and suffered laceration to the left knee due to being crushed by a car. The patient was referred to a local hospital, and contrast-enhanced computed tomography (CT) revealed that his left popliteal artery had been occluded and the left lower leg showed no arterial circulation [Figure 1a]. Although the patient was brought to our emergency unit by helicopter immediately, it took 4 and half h until his arrival. At the first examination, the patient had a crushed left knee with laceration of skin and gastrocnemius muscle. In addition, anterior and posterior cruciate, and lateral collateral ligaments and the patellar tendon were ruptured, and the popliteal artery flow had ceased. Operative exploration of the relevant arterial segment showed that the popliteal artery had been damaged severely, showing complete occlusion with a blood clot of about 3 cm. As it had already been 5 h and 50 min, the patient underwent transient external arterial bypass to immediately re-perfuse the ischemic leg [Figure 1b and c].

Owing to the re-vascularization through the transient arterial bypass, the ischemia of the foot promptly improved. After the removal of 5 cm of the damaged popliteal artery, a vein graft was inserted into the arterial defect. After the interrupted popliteal artery resumed normal blood flow, the bypass was removed and additional fasciotomy was performed. Finally, external Hoffmann fixation following tendon and ligament repair was performed. Serum creatine kinase (CK) and blood urea nitrogen (BUN) levels were elevated on the next day, but decreased the following day and normalized within 10 days [Figure 3].

Figure 3

Changes in serum blood urea nitrogen, creatine, and potassium levels (BUN: Blood urea nitrogen, K: Potassium), and creatine kinase level (CK: Creatine kinase) in Case 1 and 2

Contrast-enhanced CT performed 9 days after surgery revealed favorable popliteal arterial flow and lower leg circulation [Figure 1d]. The patient received additional skin graft to resurface the wound caused by fasciotomy 23 days after primary surgery, and he was discharged 3 weeks later, walking on his injured leg with a cane.

Case 2. Limb shunt technique

A 54-year-old man suffered from left brachial artery occlusion and left elbow joint open dislocation. He was immediately taken by helicopter after seeing a nearby doctor, but by the time he arrived at our hospital, 8 h had already passed since the injury. Contrast-enhanced CT showed complete occlusion of the brachial artery [Figure 2a]. Limb shunt (dorsalis pedis artery to radial artery) was performed immediately and revascularization of the left ischemic upper limb was started [Figure 2b and c].

Operative exploration revealed that the brachial artery had been damaged, showing complete occlusion with a blood clot of about 3 cm. After the removal of damaged artery, a vein graft was inserted into the arterial defect [Figure 2d]. Finally, external Hoffmann fixation following tendon and ligament repair was performed.

Serum CK and BUN levels were normal throughout the pre-and post-operative course [Figure 3]. Contrast-enhanced CT performed 7 days after surgery revealed favorable forearm circulation. The patient received an additional skin graft to resurface the wound caused by fasciotomy 21 days after primary surgery, and he was discharged without sensory and motor dysfunctions 3 weeks later.

DISCUSSION

Complete limb ischemia due to main extremities arterial injury, such as popliteal and brachial vessels, is associated with high amputation rates among all peripheral vascular injuries, accounting for 22%–65%.[34678] A prolonged ischemic time damages the muscles and causes postischemic syndromes, which can lead to limb amputation and impair patients’ activities and quality of lives. Hossny evaluated seven patients with popliteal artery injuries with complete lower limb ischemia and concluded that all patients with an ischemic time of longer than 6 h required amputation, compared with no patients with an ischemic time of <5 h.[9] Many investigators suggested that shortening of an ischemic time to <6 h is indispensable to prevent postischemic syndrome, such as compartment syndrome, or myonephropathic metabolic syndrome (MNMS), which resulted in ischemic contracture, muscle loss, nerve injury, and sometimes limb loss.[101112] Especially, because ischemic muscular tissue degenerates irreversibly within 6–8 h, muscle ischemia for longer than 6 h can cause necrosis.[1314] MNMS is a serious muscle reperfusion injury associated with acute renal failure and often leads to loss of limb and life. Once MNMS develops, leg amputation rates range between 40% and 50%, and mortality rates between 30% and 80%.[15]

The duration of ischemia depends on not only the vascular repair time, but also the transportation time, manpower, and preoperative examinations and preparation.[10] Grantham et al. evaluated the presurgical periods of 19 patients with upper extremity amputations and concluded that they were brought by aircraft to a tertiary surgery center with a mean time of 105.2 min and the mean presurgery time was 154.6 min.[16] Patients may take a much longer time until surgery start and are often examined and treated by few surgeons on holidays and at night-time, as in our case. In these cases, our immediate transient external arterial bypass technique can shorten the ischemic time for noncirculated legs.

A temporary arterial shunt technique was first reported by Cooley in 1956 for carotid endarterectomy and was improved to develop an intravascular shunt in the fields of cardiac and brain surgeries, such as endovascular repair of pararenal aortic aneurysms and carotid endarterectomy.[1718192021] As temporary arterial shunting after blunt limb trauma significantly reduces the total ischemic time, the routine use of shunts for popliteal artery injuries became recommended.[9] Recently, these shunts tend to be used as a component of damage control management in patients with severe, multisystem trauma. Inaba et al. evaluated 213 patients who required temporary arterial shunts and reported that 79.6% survived and the limb salvage rate of survivors was 96.3%.[22]

Our cases showed that only a 20-gauge (diameter: 1.1 mm) cannula could supply sufficient arterial blood flow for improving ischemia of extremities. Moreover, the external arterial bypass is available for any size of the artery. Our method requires only plastic cannulae and an extension tube, which are usually available in every operation room or emergency unit. Our procedure may be a favorable option for patients who require immediate circulation for ischemic legs.

Since this paper is based on two cases, there is little evidence that transient external arterial bypass definitely contributed to limb relief. However, this method reduces tissue damage caused by long-term ischemia and may help improve the functional prognosis of the limbs. We also believe that it is a useful way to avoid the systemic crisis caused by postischemic syndrome.

CONCLUSION

We presented surgical treatment for patients who suffered traumatic popliteal artery occlusion with more than 6 h of leg ischemia. Owing to transient external arterial bypass, the patients could undergo re-vascularization earlier, and the ischemic extremities were reconstructed successfully. Although a transient external arterial bypass is archaic, it is an attractive technique, especially in the management of acute traumatic ischemia of extremities to shorten the ischemic time and reduce the risk of amputation due to postischemic syndromes, which will bring the opportunity to save the ischemic extremities.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Research quality and ethics statement

The authors followed applicable EQUATOR Network (http://www.equator-network.org/) guidelines, notably the CARE guideline, during the conduct of this report.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.