Discussion
Pocket hematoma at the time of device implantation occurs in 2.1-5.3% [1] of all device implantation and can usually be managed conservatively with manual pressure. The most frequent reason for a pocket hematoma is bleeding related to the use of anticoagulation, and typically venous or capillary bleeding [2]. Usually, this bleeding is self limited and managed with manual pressure.
The arterial injury should be considered with a rapidly expanding hematoma that persists despite manual pressure and is associated with hemodynamic compromise and an important hemoglobin drop early post pacemaker implantation. In this scenario CT angiogram can confirm the diagnosis, thereby avoiding unnecessary pocket exploration. Interventional approaches including the use of coils showed in the literature that it may be therapeutic [4].
Arterial injury after device implantation is rare and reported in less than 2% of cases have post-catheterization pseudoaneurysms in upper extremity [3]. This rate is higher than we expected. At our institution 2 such complications were known to occur between January 2012 and December 2021. During this time more than 4208 new device implants were performed suggesting an incidence of less than 0.0005% for this complication making it truly rare. In our cases, venous access was obtained with the first pass so a venogram was not performed as our usual practice is to perform a venogram if access is not readily obtained. These cases highlight the proximity of branches of the main subclavian artery, namely the thoracoacromial artery and its side branches, to the axillary vein and the fact that there may be an unintended and unknown injury of these small vessels during routine and sometimes perceived uncomplicated venous access (Figure 3).
While direct cephalic cut down with visualization of the cephalic vein may avoid this complication, this approach is not always feasible. It remains unclear whether an ultrasound guided approach may facilitate identification and avoidance of injury to small arterial branches adjacent to the axillary vein [5] While venous access with ultrasound guidance may avoid pneumothorax or direct puncture of the main axillary artery if is not clear if this approach will avoid injury to small side branches of the axillary and subclavian artery as these smaller branches may not be visualized. It is possible that more distal access to the axillary vein in the region of the second rib may avoid this complication as there be fewer sub-branches in that area, but this is simply speculative as variation in arterial branching may occur in patients.
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