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Page 2 of 8 Yanagawa et al. Vessel Plus 2018;2:1 I http://dx.doi.org/10.20517/2574-1209.2017.37

ANATOMICAL CLASSIFICATION
Anatomically, traumatic PAI is classified into transection/rupture/laceration, pseudoaneurysm, dissection
and fistula.

A transection, rupture, disruption, perforation, tear or laceration of the PA is thought to be a near-complete
tear through all layers of the PA due to trauma; however, there is no consistent definitive terminology .
[1]
Clinical symptoms due to such trauma include cardiac arrest or hemodynamic insufficiency due to massive
hemorrhaging or cardiac tamponade, and dyspnea due to hemothorax or hemoptysis . Chest pain due
[1,2]
to concomitant thoracic cage injury has also been reported. Rarely, this PAI, which involves hemostasis
by clotting, is incidentally found on enhanced computed tomography (CT) without specific symptoms, as
[3,4]
whole-body enhanced CT is routinely performed in patients following a high-energy accident .
A pseudoaneurysm is an encapsulated hematoma in communication with the lumen of a ruptured vessel.
This may form when re-epithelialization of the perforation does not occur, and a delayed diagnosis can occur
[5]
even 60 years later . The pseudoaneurysm may stabilize and spontaneously resolve or expand and rupture,
depending on the etiology, size and intravascular pressure . A pseudoaneurysm can be asymptomatic
[1]
[6,7]
or characterized by symptoms of hemoptysis, shortness of breath and chest pain . An iatrogenic
pseudoaneurysm of the PA is most common, followed by trauma-induced events. A pseudoaneurysm of the
PA can also be congenital or have a non-traumatic cause, which includes infections and neoplasms .
[6,7]
An arterial fistula is an abnormal connection between the artery and other lumen organs. If an abnormal
connection between an artery and a vein occur, this is called as an arteriovenous (AV) fistula. In a trauma
setting, arterial fistulas can be asymptomatic or characterized by right ventricular dysfunction, acute
respiratory failure or transient ischemic attack (TIA) [8-12] . Traumatically, fistulas occur between the PA and
left atrium, internal mammary artery, aorta or pulmonary vein. Non-traumatic pulmonary AV fistulas can
also be associated with hereditary hemorrhagic telangiectasia . The initial clinical manifestations include
[13]
thrombotic or embolic stroke, brain abscess and TIA but can also be asymptomatic in non-traumatic cases .
[13]
The clinical trial of cyanosis, exertional dyspnea and digital clubbing is common, but there have been no
[13]
reports describing triads due to trauma .
PA dissections (PADs) are created by the occurrence of a small tear in the tunica intima, which allows blood
to enter and cause the intima layer to strip away from the media layer, in effect dividing the muscle layers of
the vascular wall. The mechanism of blunt traumatic PAD is likely similar to that seen in the aorta as a result
of shearing forces and differential deceleration of the mediastinum and the spine. However, unlike aortic
dissection, PAD progresses rapidly and typically ruptures rather than developing a reentry site, which causes
cardiogenic shock or sudden death, especially in non-traumatic cases with pulmonary hypertension . Five
[14]
major etiological groups can be identified: congenital malformation, infection or inflammation, acquired
cardiac diseases, iatrogenic causes and trauma [15-17] . Traumatic PADs usually resolve or remain stable unless
associated with pulmonary hypertension, in which case the risk of bleeding can be quite high [1,16] .

IATROGENIC PAI
The most common cause of PA ruptures and pseudoaneurysms is iatrogenic, with PA catheters being a
particularly common culprit [2,18-20] . Other iatrogenic causes include intraoperative surgical procedures [21-24] ,
indwelling chest tubes [25,26] , pacemaker implantation , central venous catheterization and Kirschner wire
[27]
[28]
migration .
[29]
[2]
The incidence of PAI induced by catheters is not very high, averaging 0.01%-0.47% . The mortality rate of
PAI induced by catheter averages 50% but can be as high as 75% in anticoagulated patients. If death occurs,