Long-term results of stent graft treatment of subclavian artery injuries: Management of choice for stable patients?

Article Outline

• Abstract
• Methods
• Results
  • Initial treatment
  • Early complications (≤30 days) (Table II)
  • Long-term follow-up and complications (Table III)
• Discussion
• Author contributions
• References
• Copyright

Background

The management of penetrating subclavian artery injuries poses a formidable surgical challenge. The feasibility of stent graft repair is already established. General use of this modality is not widely accepted due to concerns regarding the long-term outcome in a generally young patient population. We review our stent graft experience to examine long-term outcomes.

Methods

All patients with penetrating subclavian artery injuries were evaluated for stent graft repair. Patients were excluded when hemodynamically unstable or unsuitable on other clinical and angiographic grounds. Patients were followed prospectively for early (<30 days) and late (>30 days) complications. Clinical and telephone evaluation, Doppler pressures, duplex Doppler, and angiography (when indicated), were used to asses patients at follow-up. Outcomes were recorded as technical success of procedure, graft patency, arm claudication, limb loss, the need for open surgical repair, the presence or absence of other complications, and death.

Results

Fifty-seven patients underwent stent graft treatment during the 10-year period. Mean age was 34, and 91% were men. There were 53 stab wounds and four gunshot injuries. Pathology included false aneurysms (n = 42), arteriovenous fistula (n = 12), and three arterial occlusions. Early complications: One patient (2%) had a femoral puncture site injury which was managed with open surgical repair. One patient died early due to multiple organ failure related to concomitant injuries. Three patients (5%) presented with graft occlusion and nonlimb threatening ischemia in the first week after treatment. All three patients were managed successfully with a second endovascular intervention. Late complications: Twenty-five (44%) of the 57 patients with subclavian artery injuries were followed-up with a mean duration of 48 months. Two patients died as a result of fatal stab wounds months after their first injuries. Five patients (20%) and three patients (12%) presented with angiographically significant stenosis and occlusions, respectively. The stenotic lesions were successfully managed with endovascular intervention, and the occluded lesions were managed conservatively. No patient experienced life or limb loss or any incapacitating symptoms at the end of the study period. There was no need for conversion to open surgery.

Conclusions

This study has reaffirmed the feasibility and safety of stent graft repair in treating stable patients with selected penetrating subclavian artery injuries. The results of this study also confirmed acceptable long-term follow-up without any limb or life threatening complications. We conclude that endovascular repair should be considered the first choice of treatment in stable patients with subclavian artery injuries.

The management of subclavian artery injuries presents a considerable challenge to even the most experienced vascular surgeon.¹ The collective experience in treating these lesions remains limited in most vascular units. Complex surgical exposures required for conventional open repair contribute to a high morbidity and mortality.², ³ Endovascular repair offers an attractive alternative to open surgery for the management of these injuries and the safety and efficacy thereof has been previously reported.⁴, ⁵, ⁶ Concerns regarding the long-term outcome in young trauma patients prevents general acceptance. This report describes the experience and long-term results of a single vascular unit with stent graft treatment of subclavian artery injuries.

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Methods 

All patients with subclavian artery injuries presenting between November 1997 and July 2007 who qualified for endovascular repair were included in this study. Patient selection was based on clinical presentation and diagnostic angiography. Clinical contraindications to stent grafting included active uncontrollable hemorrhage, critical limb ischemia, airway or brachial plexus compression, concomitant aero-digestive injuries, and infected wounds. Arteriographic contraindications were excessive luminal discrepancy between the proximal and distal involved artery and an inability to traverse the lesion by guidewire.

The procedures were performed in an arteriography suite equipped for general anesthesia and conventional surgery. Intravenous heparin (50 units/kg) and prophylactic cefazolin were routinely administered before stent graft deployment and empirically continued for 24 hours at a dosage of 5000 units subcutaneously and 1 gram intravenously respectively every 8 hours. Transfemoral arterial access was gained under local anesthesia. Anatomical location of lesions and proximal and distal vessel diameter were determined with routine angiography, and a final decision regarding stent graft treatment was then taken. As part of this procedure, the inability to pass a guidewire and a lumen discrepancy between the proximal and distal involved arteries that would not allow proximal oversizing of 1 mm without damaging a much smaller distal artery, would exclude stent graft placement.

Details of the procedure have been previously described.⁵, ⁶ All stent grafts were placed via a percutaneous transfemoral approach. Bilateral transfemoral access (5F and 9F Cordis [Johnson & Johnson, Waterloo, Belgium] introducer sheaths) were obtained. The appropriate stent graft was introduced via the 9F sheath (11 cm in length) over a stiff guidewire, crossing the lesion, and angiographic control for precise deployment was provided by a diagnostic catheter (via the 11 cm 5F sheath) positioned in the proximal subclavian artery or aortic arch. Early in the study, long introducer sheaths (100 cm in length) were not available locally, and therefore, it was used in very few of these cases. It has the advantage of only one femoral puncture providing stent graft access and angiographic control of deployment, but in very proximal injuries achieving a stable position may be difficult. The stent grafts used included nine Hemobahn endovascular prosthesis (W. L. Gore), 20 Wallgraft (Boston Scientific, Target Therapeutics, Fremont, Calif), 27 Fluency (Bard, Murray Hill, NJ), and one custom-made stent graft consisting of a Palmaz stent with polytetrafluoroethylene (ePTFE) sutured on to it. No long-term anticoagulation or antiplatelet drugs were prescribed.

Data on each patient was collected prospectively from the time of admission. Planned postoperative evaluation included clinical and duplex Doppler evaluation after 1 month and thereafter 3 to 6 monthly, up to the end of the study. Evaluation criteria were graft patency, arm claudication, limb loss, the need for open surgical repair, the presence or absence of other complications, and death. Concerted attempts were made to trace patients not attending follow-up appointments. When telephone contact was made, the presence or absence of claudication in the relevant upper limb was established. Diagnostic and therapeutic angiography was performed if symptomatic stent graft stenosis or occlusion were suspected.

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Results 

Initial treatment 

During the 10-year study period, 145 patients with subclavian artery injuries were seen and managed. Fifty-seven patients (52 male; 5 female) with a mean age of 34 years (range 18-69) underwent stent graft treatment and the remaining 88 open surgery. Fifty-three injuries were the result of stab wounds and four were gunshot injuries. The arterial pathology is depicted in Table I. The most common injuries encountered were false aneurysms (n = 42), followed by arteriovenous fistula (n = 12). Forty-five patients were treated within 1 week of the time of injury, 11 patients within 1 month, and one patient more than 2 years after the injury. The 88 patients that underwent open surgery were excluded form stent graft treatment for clinical contraindications (n = 70), the unavailability of endovascular service after-hours (14), and radiological contraindications (4).

Table I. Subclavian arterial pathology

A variety of stent graft diameters (7-10 mm) and lengths (30-60 mm) were used. Two patients required second stent grafts to repair type 1 endoleaks caused by incorrect positioning of the first stent grafts. All patients in whom endovascular management was attempted by deployment of a stent graft were successfully treated initially. Success was defined as complete exclusion of the lesion with no endoleaks, as confirmed by completion angiography. In none of the patients in whom a stent graft was deployed was it necessary to convert to open repair, and no periprocedural blood transfusions were required.

Early complications (≤30 days) (Table II) 

One patient presented with lower limb ischemia as a result of a femoral puncture site intimal flap, requiring surgical repair. A second patient died 10 days after stent graft placement. The cause of death was multiple organ failure (this patient had multiple other injuries related to her assault). Three patients (5%) presented within the first week after treatment with early stent graft occlusions, associated clinically with nonlimb-threatening ischemia. One patient presented with proximal stent graft collapse and thrombosis. This patient had a large hematoma when he was initially treated, and it is postulated that the hematoma accentuated the compression of the stent graft between the first rib and the clavicle. He was successfully treated with catheter directed thrombolysis using streptokinase and a second stent graft to open the proximal collapsed segment of the first stent graft. This patient was still followed-up at the end of the study period (telephonical contact at 89 months) without any problems. A second patient presented with a thrombosed stent graft for no apparent reason. This was corrected with catheter directed thrombolysis and the stent graft remained patent at 36-month Duplex Doppler follow-up and asymptomatic at 88-month clinical follow-up. The third thrombosed stent graft was also treated with catheter directed thrombolysis and revealed a distal stenosis that was successfully treated in the short term with balloon angioplasty. This patient was then lost to follow-up.

Table II. Early and late complications

Early (<30 days)

Femoral artery puncture site intimal flap requiring surgical repair: 1

Early stent thromboses: 3

Death due to multiorgan failure: 1

Late (>30 days)

≥50% stent graft stenosis: 5 (mean 11 months; range 2-25 months)

Stent graft occlusion: 3 (mean 26 months; age 23-32 months)

Stabbed to death with stent grafts patent: 2 (13 and 30 months)

Long-term follow-up and complications (Table III) 

Patient availability for long-term follow-up is depicted in Table III. Thirty-one of the surviving 56 patients with subclavian stent grafts were completely lost to follow-up after their initial management. The mean duration of the follow-up of the remaining 25 patients was 49 months (range 5-104 months). Nine of these patients had incomplete follow-up, being lost before the end of the study period but 16 could still be contacted either telephonically or personally. The complete follow-up data of these 25 patients are recorded in Table IV.

Table III. Follow-up

Table IV. Follow-up data for 25 patients

PTA, Percutaneous transluminal angioplasty.

Among the nine patients that were lost before the end of the study, two late deaths, the result of subsequent violent assaults, were recorded. Both patients were asymptomatic and clinically seen with equal radial pulses and Doppler pressure measurements shortly before their deaths. Of all patients available for evaluation, five patients (20%) presented with angiographically significant (>50%) stenosis (at mean follow-up of 11 months; range 2-25 months) and three (12%) with stent graft occlusion (at mean follow-up of 26 months). The five stent grafts with stenoses were all proximal and in-stent stenoses, and one had significant poststent dilatation that remodeled on follow-up after balloon angioplasty. In total, significant stenosis or occlusion took place in eight (32%) of the 25 patients available for long-term follow-up. These eight patients all presented with non-incapacitating claudication, and the stenotic lesions were all successfully treated with angioplasty and remained patent on follow-up. Occlusions were treated conservatively, without a requirement for open surgery to improve symptoms or to achieve limb salvage. No patient needed open surgery on long-term follow-up. The three stent grafts presenting with occlusion all presented late and no attempt at chemical or mechanical thrombolysis were made. Structurally, these seven stent grafts were intact, and no evidence of stent graft fracture or compression between the first rib and clavicle were present. None of the patients presented with early or late graft sepsis.

In total, stent graft failures amounted to six occlusions (three early; three late) and five significant (>50%) stenoses (two within 6 months and the remainder late). None of these stent grafts were Hemobahn (nitinol) stents, 10 were Wallgraft (stainless steel) stents, and one was a Fluency (nitinol). The failure rate for the Hemobahn stents was none of nine, for Wallgraft stents 10 of 20 (50%), and for the Fluency stents, one of 27 (4%). The patient with the custom-made stent graft remained asymptomatic for the duration of the study.

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Discussion 

The treatment of subclavian artery injuries can pose a major challenge even in the elective setting where access may requires a sternotomy or thoracotomy.⁷, ⁸, ⁹ Overall mortality, including deaths at the scene, is reported to be as high as 70% to 80% and, in patients surviving to the operating room, 5% to 15%.⁹ We and others previously reported the endovascular management of these injuries in selected patients to be a safe, effective, and minimally invasive alternative to open repair.⁶, ¹⁰ This was again confirmed in this large study with a technical success rate of 100% and no procedure-related deaths or limb loss occurring. Early stent graft failure (within 30 days) occurred in three of 57 subclavian artery injuries (5%). Review of the literature on open repair of subclavian artery injuries, reveals early failure rates reported by McKinley et al¹¹ (12 of 236 repairs) and Degiannis et al¹² (3 of 54 repairs) to be about 5%. As a whole, the early graft failure rate of endovascular repair of this vessel compares favorably with open repair. None of these patients presented with critical arm ischemia or other thromboembolic complications. Two of them were, after the initial correction of patency, followed-up for more than 7 years with no upper limb complaints. All three stent graft thromboses occurred early in our experience and with Wallgrafts. Factors that could have played a role include choosing a too short stent graft, not covering all residual clots in the vicinity of the injury, and compression of the less flexible stents, especially when used in patients with large false aneurysms, causing compression of the device in relation to the clavicle and first rib. In this study, no short or long-term antiplatelet therapy was attempted due to poor patient compliance. It might be of some benefit in terms of stent graft patency in individual patients in a more reliable patient population.

As a result of the notorious difficulty in follow-up of trauma patients, long-term outcome statistics are difficult to collect. The same is true for open surgery and medium-/long-term data following the performance of open surgery in this group of patients is lacking. This series presents a single center experience with the endovascular treatment of a selected group of patients with an intensive effort to maintain follow-up during a 10-year period. We initially planned to asses all patients on follow-up by clinical examination (comparing radial pulses), Doppler pressure comparison, duplex Doppler scanning, and angiography where necessary. Duplex Doppler study can be inaccurate in the assessment of subclavian stent graft patency due to the difficulty in visualizing the artery posterior to the clavicle and sternum. As the study progressed, it became increasingly difficult to have patients attend follow-up visits, especially those without symptoms or complications. We therefore relied more on clinical evaluation, Doppler pressures, and telephonical interview to detect pulses, incapacitating symptoms, limb or life loss, or the need for open surgery elsewhere. Although objective assessment of stent graft patency cannot be claimed, due to erratic patient attendance for follow-up, the success of treatment in terms of limb salvage, absence of incapacitating symptoms, and survival has been determined with reasonable accuracy.

Although the number of patients successfully followed-up was only 26, the mean follow-up was fairly long at about 4 years. The 16 patients that were still followed-up at the end of the study had a mean follow-up of 61 months (range 8-104). All these patients were alive, actively using their arms without significant claudication, and with no other stent graft related problems. The five patients (19%) who complained of claudication all had significant stenoses on arteriogram. We treated them all aggressively and successfully with balloon angioplasty. In most of these patients, the claudication was mild and could probably have been initially managed conservatively. Three patients (12%) with occlusions were all asymptomatic or experienced nonincapacitating symptoms that did not need further treatment. Review of the literature fails to identify any long-term follow-up results for open surgical repair of subclavian artery injuries. This can be ascribed to the unreliable nature of trauma patients and their generally poor socioeconomic status.

Elective surgery for nontraumatic pathology of these vessels does not represent a comparative model as the data is limited and patient profile and differences in pathology are confounding factors. It cannot be stated precisely how many of the stent grafts are patent, but it can be said that, of the 26 patients who were followed-up, none experienced any limb or life threatening complications. This was also true for the 16 patients that were still followed-up at the end of the study (mean follow-up 61 months) and, of these, six patients had a patent graft on clinical examination (mean follow-up 72 months).

A superiority of the more flexible Hemobahn and Fluency stent grafts in comparison with the more rigid Wallgraft in the tortuous subclavian artery in terms of patency, stent deformation and stent compression has been reported by others,¹³, ¹⁴, ¹⁵ and was also demonstrated in this series. All three stents are self expandable with the Hemobahn and Fluency consisting of a nitinol stent covered with ePTFE and the Wallgraft being a super metal alloy-composed (Elgiloy) stent, covered with woven low-porosity polyethylene terephthalate. Combined failure rate for the nitinol/ePTFE stents were 3%, and 50% for the Wallgraft. It is unclear whether the stent metal, covering material, or both contributed to the difference in outcome. No instance of stent graft fracture in either group was encountered on follow-up; a complication that has been described by other authors for bare stents and covered stents in the subclavian artery. This, however, only holds true for patients presenting with complications and a few others undergoing radiological imaging at some stage. No significant endoleaks translating to growing false aneurysms or other complications were encountered.

It is concluded that stent graft management of selected subclavian artery injuries is safe with morbidity and mortality rates comparable with open surgery. The long-term results demonstrated in this study are acceptable, and there are no published results available to provide any evidence that open surgery might be better. In this unit, we therefore would consider any patient stable enough to undergo an angiogram as a possible candidate for stent graft treatment if a subclavian artery injury is demonstrated. Emerging clinical contraindications to endovascular management include a large hematoma causing compression symptoms, concomitant injuries that warrant exploration in their own right, such as tracheal or esophageal injuries, and grossly infected wounds that might lead to graft sepsis. Technical restrictions include a significant lumenal size discrepancy between the proximal and distal parts of the involved artery, leading to graft sizing difficulties, with the possibility of proximal endoleaks, or distal over sizing and vessel damage. This is especially problematic when treating chronic arteriovenous fistulae and can be partly overcome by using tapered stents. Other technical restrictions include an inability to traverse the lesion with a guide wire. This is a potential problem with old arteriovenous fistulae, false aneurysms, and arterial occlusions with widely displaced proximal and distal arterial lumens. Femoral and brachial punctures with snaring of the femoral guide wire in the lesion via the brachial approach may potentially address this problem. In this experience, 39% of all patients with subclavian artery injuries qualified for stent graft treatment. We believe that, with improving endovascular techniques and increasing general acceptance of this modality, up to 50% of injuries can be treated endovascularly. This correlates well with a retrospective evaluation by Xenos,¹⁶ demonstrating a 52% suitability of their patients for endovascular repair. Stent graft repair is now our first choice in the management of selected, stable patients with subclavian artery injuries.

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Author contributions 

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References 

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