Raghav Gupta1, Andre Jared2, James Mahoney1. 1. Department of Pulmonary and Critical Care Medicine, SUNY Downstate Medical Center, Brooklyn, New York, USA. 2. Department of Internal Medicine, SUNY Downstate Medical Center, Brooklyn, New York, USA.
Dear Editor,Venous-bronchial fistula is a rare and life-threatening entity. The risk factors associated with the development of fistula are few, but known. As much as possible, it is important to understand the risk factors to prevent the formation of venous-bronchial fistula. Here, we present a very interesting case of venous-bronchial fistula found incidentally on routine angiography leading to acute hypoxemic respiratory failure.A 65-year-old woman with a history of end-stage renal disease on hemodialysis was referred to the hospital for the diagnostic angiography for malfunctioning of proximal left upper extremity brachial artery to axillary vein arteriovenous fistula (AVF). She had a history of recurrent stenosis of AVF and failed balloon angioplasty requiring placement of endovascular self-expanding nitinol stent. Angiography revealed extravasation of contrast material from the left axillary vein into the bronchial tree and into bilateral main stem bronchi more in the left suggesting a venous-bronchial fistula [Figures 1 and 2]. Chest radiography revealed patchy opacification of the left hemithorax. The patient was subsequently intubated for worsening hypoxemia and was transferred to Intensive Care Unit. A new stent was placed which successfully sealed off the fistula. Further injecting contrast into the vein, there was no further extravasation into the bronchi [Figure 3]. We, hereby, present a rare case of venous-bronchial fistula caused by the erosion of the old stent into the wall of the vessel creating a new tract. The patient showed rapid clinical and radiographical improvement on the closing of the venous-bronchial fistula and got successfully extubated on the next day.
Figure 1
Angiography showing an extravasation of contrast material from the left axillary vein into the bronchial tree and left main bronchi
Figure 2
Angiography showing an extravasation of contrast material from the left axillary vein into the bronchial tree, left main bronchi, and right main bronchi
Figure 3
Angiography revealing complete closure of the fistula with no leakage of the contrast into the bronchial tree after placement of the new stent
Angiography showing an extravasation of contrast material from the left axillary vein into the bronchial tree and left main bronchiAngiography showing an extravasation of contrast material from the left axillary vein into the bronchial tree, left main bronchi, and right main bronchiAngiography revealing complete closure of the fistula with no leakage of the contrast into the bronchial tree after placement of the new stent
DISCUSSION
Venous-bronchial fistula is an extremely rare finding and often caused by long-term central venous catheters (CVCs).[1] The possible mechanism is friction between the catheter tip and vessel wall by withdrawing blood or by vessel wall irritation with chemotherapy or hyperalimentation agents.[234] Malposition of CVC in the azygos vein is another reportable cause of fistula. It is caused by low blood flow in azygos vein with its proximity to right main stem bronchus.[5] The stent placement for AVF is recommended when recurrent venous stenosis is present or when surgical revision is not possible.[6] Hereby, we report a rare case of venous bronchial fistula caused by the erosion of the stent which was originally placed for the recurrent venous stenosis in hemodialysis venous access. The erosion of the stent into the wall of the vessel created a new tract leading to venous-bronchial fistula. The patient showed remarkable clinical and radiographical improvement on the immediate closing of the fistula by the stent.
CONCLUSION
Evaluation of early removal of CVC and radiographic confirmation of catheter tip is important for the prevention of venous-bronchial fistula. Patients receiving long-term chemotherapy and hyperalimentation agents through CVC carry high risk for venous-bronchial fistula, and high suspicion is needed. Our case highlights the additional risk factor of leaking stent in proximal left upper extremity brachial artery to axillary vein AVF causing the formation of venous bronchial fistula. This case will lead to more expert research in the better understanding of the stent placement, which can further prevent such life-threatening complication. Furthermore, in our case, the placement of the new stent to seal off the fistula showed a good clinical outcome.
Figure 1
Figure 2
Figure 3