History

A 2-year-old 24.6-kg (54.1-lb) castrated male German Shorthaired Pointer was referred because of a suspected bronchial foreign body. The dog had been examined 1 day earlier by the referring veterinarian because of a 2-day history of lethargy and possible lameness in the right pelvic limb. Results of a CBC performed by the referring veterinarian indicated mild neutrophilia, and results were negative for a heartworm test and a fecal flotation test. Radiography revealed unremarkable findings for the abdomen but a presumptive bronchial foreign body at the level of the right middle lung lobe (not shown); the owners reported that the dog had no history of coughing or abnormal respiratory signs. The referring veterinarian hospitalized the dog overnight; initiated treatment with ampicillin-sulbactam (24.4 mg/kg [11.1 mg/lb], IV, q 8 h), metronidazole (dosage unknown), and fluid therapy (type and dosage unknown); and referred the dog the next day for removal of the suspected bronchial foreign body.

On referral examination, the dog was bright, alert, and responsive and had vital signs within reference limits and no signs of lameness. Thoracic radiography was performed (Figure 1).

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Left lateral (A) and ventrodorsal (B) thoracic radiographic images of a 2-year-old 24.6-kg (54.1 -lb) castrated male German Shorthaired Pointer with a 2-day history of lethargy; the dog had been referred for removal of a potential thoracic foreign body.

Citation: Journal of the American Veterinary Medical Association 258, 9; 10.2460/javma.258.9.953

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Diagnostic Imaging Findings and Interpretation

Thoracic radiography revealed a long, slender, mineral opaque structure (approx 5 × 0.2 cm) that spanned from the level of the carina craniodorsally to the level of the sixth rib caudoventrally (Figure 2). This structure was possibly in the right middle lobar bronchus, artery, or parenchyma. Other radiographic findings were unremarkable.

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Same images as in Figure 1. A long, slender, mineral opaque structure (arrows) is present in the area of the right middle lobar bronchus, artery, or parenchyma. All other pulmonary structures are radiographically unremarkable.

Citation: Journal of the American Veterinary Medical Association 258, 9; 10.2460/javma.258.9.953

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Bronchoscopic evaluation of the airways revealed a mild amount of mucus within the right caudal bronchus but no other abnormalities (not shown). Because these findings ruled out bronchial involvement, the dog underwent general anesthesia for thoracic CT^a to further localize the foreign material. On precontrast CT, a mineral-attenuating structure (approx 5 × 0.2 cm) was identified in the proximal aspect of the right middle lobar pulmonary artery. To verify the intravascular location of the foreign material, contrast medium (iohexol; 240 mg of I/mL, 75 mL, IV) was administered, and postcontrast CT images were obtained (Figure 3). The proximal-most aspect of the structure was at the level of the branching of the right middle and right caudal lobar arteries. No abnormalities were seen in the pulmonary parenchyma. Given the CT and radiographic appearance and location of the foreign material, it was suspected to have been a fragment of a peripheral intravenous catheter (PIVC). After CT, the dog recovered from anesthesia without complication and was scheduled for surgery to remove the foreign material.

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Postcontrast transverse (A), sagittal (B), and dorsal (C) plane reformatted maximum intensity projection CT images of the thorax of the dog described in Figure 1. A 5-cm-long × 0.2-cm-diameter mineral-attenuating structure (arrows) is in the proximal aspect of the right middle lobar pulmonary artery. The lines across the images represent the planes of the orthogonal images (pink for transverse, yellow for sagittal, and green for dorsal). A— The dog's right is to the left of the image (soft tissue window [window width, 657 HU; window level, 37 HU]; 3-mm slice thickness). B—The dog's head is to the left of the image (soft tissue window [window width, 466 HU; window level, 37 HU]; 3-mm slice thickness). C—The dog's right is to the left of the image (soft tissue window [window width, 374 HU; window level, 125 HU]; 3-mm slice thickness).

Citation: Journal of the American Veterinary Medical Association 258, 9; 10.2460/javma.258.9.953

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Treatment and Outcome

One week later, the dog underwent general anesthesia and percutaneous endovascular removal of the foreign body from the right middle lobar pulmonary artery. An area over the dog's right jugular vein was aseptically prepared, and a 4F end-hole catheter was percutaneously introduced into the jugular vein and advanced with fluoroscopic guidance and serial fluoroscopic angiography into the right middle pulmonary artery. A 10-mm gooseneck snare^b was advanced through the lumen of the end-hole catheter and used to snare and remove the foreign body (Figure 4), which when examined was confirmed to have been a fragment of a PIVC (Figure 5). The dog recovered uneventfully and was discharged the following day with a prescription of cephalexin (25 mg/kg [11.4 mg/lb], PO, q 12 h for 14 days). During a recheck examination 2 weeks after surgery, the dog was clinically normal.

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Fluoroscopic image obtained over the cardiac silhouette of the dog described in Figure 1 during percutaneous endovascular removal of a foreign body (white arrow) from the dog's right middle lobar pulmonary artery with the use of a 10-mm gooseneck snare (black arrow) advanced through the lumen of a 4F end-hole catheter placed in the dog's right jugular vein.

Citation: Journal of the American Veterinary Medical Association 258, 9; 10.2460/javma.258.9.953

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Postoperative image of the peripheral intravenous catheter fragment grasped by the gooseneck snare used during percutaneous endovascular removal of the fragment from the dog's right middle lobar pulmonary artery.

Citation: Journal of the American Veterinary Medical Association 258, 9; 10.2460/javma.258.9.953

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Comments

For the dog of the present report, the finding of a mineral opaque structure with similar dimensions as a PIVC prioritized catheter-fragment embolism on our differential diagnosis list. Peripheral intravenous catheter embolization is an uncommon complication of the use of PIVCs but has been reported in human^1,2 and veterinary³ medicine. The overall rate of PIVC fragmentation is unknown and suspected to be rare.⁴ Most instances of PIVC fragmentation are iatrogenic and occur during placement (eg, with multiple placement attempts or poor technique), prolonged cannulation, or removal of the PIVC; however, self-inflicted PIVC fragmentation has also been reported.^1,2 Also in people, complications associated with PIVC embolization (eg, arrhythmias, cardiac perforation, myocardial infarction, thrombosis, endocarditis, sepsis, and vascular wall perforation) lead to an overall mortality rate of 1.8% (4/215).^1,2,3 Although clinical signs can be severe, with the highest morbidity rate among those with catheter-fragment embolism of the right ventricle, a study² of 215 people with catheter-fragment embolisms from PIVCs or implanted (port) catheters shows that 52 (24.2%) of the affected individuals had no symptoms and that the embolizations were found incidentally on thoracic radiography between 10 days and 25 years after the suspected fragmentation incident. For the dog of the present report, the catheter fragmentation incident was suspected to have occurred within 6 months before PIVC embolization was diagnosed, given that the only previous treatment that had involved placement of a PIVC was 6 months earlier when the dog was castrated.

In human medicine, the most common location for a fragmented catheter to embolize is the pulmonary artery.² Similarly, in the dog of the present report, radiographic evidence suggested that the right middle lobar bronchus, artery, or parenchyma could have been involved, and only with CT could we see that the PIVC fragment was in the right middle pulmonary artery, with the fragment's proximal-most end located at the level of the branching of the right middle and right caudal lobar arteries.

Because of the potential risk of serious complications from catheter-fragment embolization, removal at the time of diagnosis is recommended.² In veterinary³ and human^4,5 patients, a percutaneous endovascular technique with fluoroscopic guidance and serial fluoroscopic angiography, as used in the dog of the present report, is effective and relatively safer than thoracotomy. For the technique, we used a gooseneck snare, which required an end of the catheter fragment to be free so that the loop of the snare could be advanced around the fragment to properly grasp and remove it.⁵ The most common complications reported with this procedure in dogs, goats, and horses include transient arrhythmias and procedural failure to remove the foreign body.³ In a study⁴ on human patients, the complication rate was 2% (1/52) for affected patients undergoing the percutaneous endovascular procedure versus 21% (16/76) for those not undergoing this procedure. No complications were observed during or after the procedure in the dog of the present report.

The present report depicted diagnostic and treatment challenges for PIVC embolism, which is infrequently reported in veterinary medicine. Thoracic radiography revealed the catheter fragment but could not identify the soft tissue structures in which it was lodged. Bronchoscopy ruled out bronchial involvement, then pre- and postcontrast CT were used to further localize the foreign body and guide our treatment decisions, such as percutaneous endovascular removal versus thoracotomy. Findings on CT were indispensable in the decision to perform percutaneous endovascular removal of the PIVC embolism with a gooseneck snare. The surgical treatment was effective and relatively safe, easy, and rapid. We recommend that advanced imaging with CT be performed on similarly affected patients so that optimal and prompt removal of catheter-fragment embolisms can be attempted.