Keywords pseudoaneurysm - artificial vessel graft - brachial artery
Introduction
Arterial pseudoaneurysms occur when a hematoma forms after disruption of the arterial
wall. This presents as a pulsatile hematoma in the artery. It frequently occurs in
the cerebral arteries and brachial arteries are affected in 3 to 10% of the time.[1 ] Brachial artery aneurysm is a rare disease. It usually occurs as a false aneurysm
secondarily caused by infection, trauma, or iatrogenic event.[2 ] Specifically, brachial mycotic pseudoaneurysm can arise rarely after infective endocarditis.[1 ]
[3 ]
[4 ] With infection of the arterial wall, pseudoaneurysm formation can occur without
any iatrogenic injury from surgical or endovascular arterial intervention.[1 ] This is referred as mycotic aneurysms.
Mycotic aneurysm commonly occurs from septic emboli created by native or prosthetic
valve endocarditis, intravenous drug abuse, or invasive endovascular catheter use.[1 ] Mycotic pseudoaneurysm occurs in the upper limb in 10% of the cases and the prevalence
is known to be 0.03% annually.[1 ] Despite its low incidence, prompt diagnosis and treatment are necessary to prevent
severe complications such as limb amputation.[5 ]
Case
We report a case of a 71-year-old male who presented with a mass in his right antecubital
fossa that increased in size slowly over time. Three years ago, the patient underwent
ascending and total arch replacement with artificial vessel graft to treat aortic
root and ascending aorta aneurysm. One year ago, the patient was admitted for treatment
of infective endocarditis. Infection subsided without complication. Preoperative physical
examination of right upper extremity showed a nonpulsatile mass with normal pulse
of axillary, brachial, and radial arteries. No signs of inflammation or infection
were present. Preoperative clinical photo of the patient's arm is shown in [Fig. 1 ]. Initially, the authors' first impression of the disease was a simple hematoma.
Preoperative computed tomography (CT) showed an 8 cm × 2.8 cm × 3.5 cm soft tissue
mass as shown in [Fig. 2 ]. Thus, further CT angiography or invasive arteriography were not performed. Intraoperatively,
a mass encircling the brachial artery was identified. The mass along with part of
the brachial artery was removed. A 1.5-cm length defect of the brachial artery was
replaced by a 1.5-cm sized circumferential great saphenous vein was harvested to reconstruct
the removed portion of the brachial artery as shown in [Fig. 3 ].
Fig. 1 Preoperative clinical photo showing palpable mass in patient's elbow.
Fig. 2 Preoperative computed tomography showing an 8 cm × 2.8 cm × 3.5 cm soft tissue mass.
Fig. 3 Great saphenous vein graft used to reconstruct excised aneurysm from brachial artery.
Two months later, the patient presented with pain and limited range of motion of his
elbow. Severe bruising and edema were present, but no sign of vascular ischemia was
present at the distal end as shown in [Fig. 4A ]. A pulsatile mass was presented in his elbow. For further evaluation, CT angiography
revealed a 7 cm × 7 cm sized pseudoaneurysm in the right brachial artery as shown
in [Fig. 4B ]. Surgical exploration was done in the operation room. The patient was laid supine
with right upper arm abducted. A longitudinal incision on the medial side of the arm
and transverse incision along the antecubital fossa were made. Unlike the first operation,
the authors had to overcome some difficulties. Diffuse swelling, edema, and fibrotic
tissue were present in the entire elbow. This made identification of anatomical landmarks
and dissection very difficult, leading to increased operation time. Due to increased
operation time, arm tourniquet had to be disabled frequently. Even with tourniquet
apply, sluggish venous oozing was present in the operation field.
Fig. 4 (A ) Two months later, the patient presented with pain and limited range of motion of
his elbow. Severe bruising and edema were present. (B ) Computed tomography angiography after recurrent mass showing a 7 cm × 7 cm sized
pseudoaneurysm in brachial artery.
A pseudoaneurysm has recurred and capsule formation extended distally toward radial
and ulnar arteries. Extensive capsulectomy and adhesiolysis were performed. Despite
risk of massive hemorrhage and injury to surrounding neurovascular and muscular structure,
complete excision of the pseudoaneurysm pouch was done to find the proximal ends of
radial and ulnar artery and the distal end of brachial artery. This left about a 10-cm
sized defect in the right brachial artery including the bifurcation point of brachial
artery. A Y-shaped GORE-TEX artificial vessel graft was used for inter positioning
between brachial artery and radial and ulnar artery for revascularization as shown
in [Fig. 5 ]. Permanent biopsy result showed pseudoaneurysm and all microbial results were negative.
Follow-up of the patient at 6 months showed no recurrences or wound problem as shown
in [Fig. 6 ]. An invasive arteriography or CT angiography were not performed but a hand-held
Doppler device patency of both the radial and ulnar side artificial vessel. The patient-reported
partial sensual recovery.
Fig. 5
Y -shaped GORE-TEX artificial vessel graft used as interposition graft connecting brachial
artery with radial and ulnar arteries.
Fig. 6 Follow-up clinical photo at 6 months without sign of recurrence.
Discussion
Arterial aneurysm is defined as a region where 50% increase in diameter compared with
its normal value of artery is observed.[6 ] False aneurysms occur by hemorrhage and extravasation caused by traumatic puncture
of vessels. Fibrosis of hematoma causes false aneurysms.[6 ] True aneurysms are formed when gradual increase in arterial diameter occurs due
to vessel damage.[6 ] Brachial artery aneurysm is a rare disease. It usually occurs in the form of false
aneurysm and its prevalence is reported as 0.5%.[2 ] It develops slowly from months to years for development of any clinical symptoms.[6 ] It is known to be caused secondarily by atherosclerosis, blunt/penetrating trauma,
or other diseases such as neurofibromatosis, Karposi's sarcoma, Kawasaki's disease,
or Buerger's disease.[2 ] Penetrating trauma, such as stabbing, is more common while blunt trauma may also
cause the disease in patients who are hemorrhagic.[5 ] Aneurysms arising after blunt trauma caused by humeral fracture has been reported.[7 ] In our case, the patient had preceding infective endocarditis after ascending and
total arch replacement. The mass was first noticed by the patient 3 years after aorta
replacement and 1 year after incidence of infective endocarditis.
Brachial mycotic pseudoaneurysm is an uncommon complication of infective endocarditis.[1 ]
[3 ]
[4 ] Among upper extremity mycotic pseudoaneurysm, brachial artery is the most commonly
affected site. The most common risk factor is prosthetic valve endocarditis[1 ] which was the case in our patient. The pathophysiology of the disease is the formation
of aneurysm by the occupation of arterial vasa vasorum wall by septic emboli coming
from infective endocarditis.[1 ]
Patients may not show any symptoms when aneurysms are small. This is why our patient
has presented with a palpable mass years after aorta replacement and infective endocarditis.
The most common symptoms are pain, swelling, and neurological signs caused by compression
of median nerve.[8 ] A pulsatile mass accompanying induration and erythema may present.[6 ] Bruit or thrill can be audible. If the lesion enlarges and compresses surrounding
neurovascular structure, pain and edema of the extremity can develop. The symptoms
can be relieved after complete resection of the aneurysm. If thromboembolism develops,
limb ischemia may occur which may require distal amputation if treatment is delayed.[8 ]
Diagnosis can be done using imaging such as ultrasonography or CT angiography.[2 ] On diagnosis, intervention either open surgery or endovascular approach is recommended
to avoid complication.[2 ] With open surgery approach, the lesion can be approached simply with great exposure.[2 ] Delay in treatment may lead to upper limp ischemia, edema, hemorrhage, and neurological
symptoms. The affected brachial artery with pseudoaneurysm should be resected along
with debridement of any surrounding tissue accompanying infection or necrosis. Immediate
revascularization should be done. Simple repair or end-to-end anastomosis with interrupted
or running suture can be done with small lesions.[1 ] Too much tension may lead to thrombosis of anastomosis site. If the lesion is distal
to the bifurcation point of brachial artery, the aneurysm can be simply ligated.[5 ] However, as in our case, if the aneurysm affects the bifurcation point, reconstruction
is necessary for maintaining adequate vascularization to the distal extremity.[5 ] For large defects, interposition can be done using autologous vessel graft or prosthetic
conduit.[1 ] Using prosthetic conduit may have long-term problems or potentially cause infection.[8 ]
If patients accompany with limb ischemia, embolectomy with Fogarty catheter can be
considered. However, severe complications, such as limb amputation, brachial plexus
injury, and flexion contracture, must be considered.[1 ] As opposed to surgery, endovascular procedure can be attempted to apply stent in
the affected region if infection is not present. If infection is present, intravenous
antibiotics and valve replacement of infected valve must be considered.[1 ] Injecting thrombogenic agents to block the aneurysm has been reported.[8 ] However, this may cause complications associated with vessel thrombosis.
In our case, the mass was first explored in open surgery. Despite successful removal
of pseudoaneurysm and reconstruction with a 1.5-cm sized circumferential saphenous
vein graft, a recurrent pseudoaneurysm appeared 2 months later. Autologous vein graft
failure can be divided by three phases. Early failure occurs often within 1 month
due to thrombosis. This may be due to endothelial injury during harvest procedure
or exposure to arterial pressure that increases shear stress to the vein. Consequently,
this leads to vein graft thrombosis. Intermediate failure occurs between 1 month and
1 year. As the vein graft is exposed to high arterial pressure, neointimal hyperplasia
occurs which eventually cause graft luminal loss and atherosclerosis. Late failure
occurs beyond 1 year due to progressive calcified atherosclerosis.[9 ]
[10 ]
[11 ] In our case, the pseudoaneurysm appeared 2 months later. Thus, a mixture of early
and intermediate failure seems to be present. Due to the increased arterial pressure,
the vein graft distended to appear as an aneurysm. This may have caused the remnant
artery to further dilate toward the distal portion. The recurred pseudoaneurysm extended
distally toward the radial and ulnar artery including the bifurcation point of brachial
artery. The extended pseudoaneurysm and capsule formed after the first operation were
totally removed. The reconstruction was challenging due to massive hemorrhage and
due to the need for reconstruction of the bifurcation point to revascularize both
ulnar and radial arteries. Reconstruction was successfully done using a Y -shaped GORE-TEX artificial artery graft. When comparing synthetic vessel graft with
autologous grafts, synthetic grafts have lower long-term patency and higher infection
risk.[12 ]
[13 ] In our second operation, there was about a 10-cm Y -shaped defect. Because of the large defect required for reconstruction and initial
failure of autologous vein graft, an artificial GORE-TEX vessel graft was chosen for
reconstruction.
We present a rare case of brachial artery pseudoaneurysm with history of infective
endocarditis following previous artificial vessel graft placement in the aorta. Pseudoaneurysm
was removed successfully without injuring surrounding soft tissue including nerve,
muscles, and tendon. The arterial defect caused by excision of pseudoaneurysm was
reconstructed successfully with a bifurcated Y -shaped artificial vessel graft after recurrence of the aneurysm after initial reconstruction
with saphenous vein graft.
