Fistula from Right Internal Mammary Artery to Superior Vena Cava after Use of a Laser Sheath to Extract a Pacemaker Lead

Abstract

A 55-year-old woman presented with dyspnea on exertion due to a right internal mammary artery-to-superior vena cava arteriovenous fistula that occurred after pacemaker lead extraction with a laser sheath. The fistula was successfully repaired by placing a covered stent in the right internal mammary artery. In this unusual location, endovascular stenting is a reasonable alternative to coil embolization or surgical repair of an arteriovenous fistula resulting from laser lead extraction.

The number of new patients with permanent pacemakers (PPMs) and implantable cardioverter-defibrillators (ICDs) continues to rise, and previously placed PPM–ICD leads are aging. As foreign bodies in the blood vessels, pacer leads are associated with certain potential sequelae, which include infection, venous obstruction, thrombosis, and arteriovenous fistula (AVF) formation.^1–4 Some of these complications warrant lead removal, but this can cause adverse events on its own. The risk increases the longer the lead is left in place.^2–4 We describe the case of a patient who developed a right internal mammary artery (RIMA)-to-superior vena cava (SVC) fistula after lead removal by means of a laser sheath. This is an unusual location for such a fistula.

Case Report

A 55-year-old woman presented at our hospital with a skin infection above her left breast, where a dual-chamber PPM–ICD generator had been implanted with tunneled leads (Fig. 1). The patient had an extensive medical history that included congenital heart block and cardiac arrest related to ventricular fibrillation. Several PPM–ICDs had been implanted and later (because of pocket infections) removed. A pair of atrial and ventricular leads was still present from a previously removed right-sided device (Fig. 1).

Fig. 1 Before lead extraction, chest radiographs in A) the posteroanterior projection and B) the lateral projection show the permanent pacemaker–implantable cardioverter-defibrillator in a low left pectoral position, along with its 2 leads. Two additional, nonfunctional leads are present from a previous right-sided device.

The patient was taken to the cardiovascular hybrid suite, where the PPM–ICD and all 4 leads were removed, without apparent complications, by using 12F and 16F excimer lasers (Excimer CVX-300® Laser System; The Spectranetics Corporation; Colorado Springs, Colo). Because the patient was pacemaker-dependent, a temporary transvenous pacemaker was inserted until the infectious process resolved. A week later, a new PPM–ICD was inserted in the right pectoral area, and the patient was discharged from the hospital without symptoms.

At a follow-up visit 4 weeks later, she reported mild shortness of breath and had a new continuous murmur that was best heard on the upper right sternal border. This finding prompted the physician to suspect an AVF. Although a computed tomographic angiogram failed to disclose a communication, contrast angiography revealed an AVF between the proximal RIMA and the SVC. Pre- and post-fistula stenosis of approximately 90%, with pseudoaneurysm formation, was noted.

To close the AVF, we engaged the RIMA with an 8F hockey-stick guiding catheter, which was inserted percutaneously through the right femoral artery (Fig. 2). Because of the 90% proximal and distal stenoses, the fistula was difficult to cross with a single wire, so we created a buddy system by placing a Hi-Torque Spartacore 0.014-in wire (Abbott Vascular, part of Abbott Laboratories; Redwood City, Calif) across the fistula into the SVC while advancing a HI-TORQUE WHISPER 0.014-in coronary guide wire (Abbott Vascular) through to the distal RIMA. To choose the appropriate stent size, we used an Eagle Eye® Platinum intravascular ultrasound catheter (Volcano Corporation; San Diego, Calif) to evaluate the vessel's diameter. Subsequently, we deployed a 5 × 16-mm iCAST™ covered stent (Atrium Medical Corporation; Hudson, NH) in the RIMA across the fistula. Figure 3 shows the stent positioned across the fistula before deployment. At the end of the procedure, angiography displayed no evidence of the AVF (Fig. 4).

Fig. 2 Selective angiography of the right internal mammary artery (right anterior oblique projection) shows a large arteriovenous fistula filling the superior vena cava. To close the fistula, we engaged the right internal mammary artery with an 8F hockey-stick guiding catheter, which was inserted percutaneously through the right femoral artery.

1 = 8F internal mammary artery guiding catheter; 2 = proximal right internal mammary artery; 3 = arteriovenous fistula; 4 = superior vena cava

Fig. 3 Angiography shows the 5 × 16-mm covered stent positioned across the fistula before deployment.

Fig. 4 After placement of the stent-graft, repeat selective angiography of the right internal mammary artery (right anterior oblique projection) shows that the arteriovenous fistula is totally sealed.

1 = proximal right subclavian artery; 2 = proximal right internal mammary artery without evidence of a fistula

Discussion

In this case, an AVF between the RIMA and the SVC was associated with PPM–ICD lead extraction by means of a laser sheath. The patient's symptoms were delayed in onset but progressive. If the fistula had not been corrected, it might have led to high-output cardiac failure. This case was complicated by an aneurysmal lesion, with 90% stenosis proximal and distal to the fistula, which we were able to exclude safely by placing a covered stent.

When PPM–ICD leads are first inserted in a vessel, thrombus formation occurs, and the thrombus subsequently organizes. Over time, fibrosis continues along the lead, predominantly in areas that are in contact with the vascular endothelium and endomyocardium.^5,6 These changes, which are basically inflammatory in nature, can extend to nearby arteries, making them more susceptible to injuries. Also, at the time of insertion, a lead might inadvertently follow a route across an arterial vessel before ending in the vein, which predisposes the patient to AVF formation. This usually happens close to the puncture site, thereby involving the subclavian vessels.

In 0.7% to 3.4% of cases, lead extraction results in serious sequelae, the most frequent of which are tamponade, vessel laceration, pneumothorax, hemothorax, stroke, and arrhythmias.^1–4 The Excimer CVX-300 Laser System is one of several systems that have been developed to facilitate PPM–ICD lead extraction. The “powered” extraction sheath is advanced over the lead by means of reduced counterpressure and countertraction. The cool pulses of the ultraviolet laser (308-nm wavelength) at the tip of the sheath create a 50-μm-deep dissection plane along the fibrous tissue surrounding the lead.

The use of laser sheaths increases the procedural success rate but is not free of sequelae. Wilkoff and associates⁴ achieved a significantly higher success rate by extracting leads with laser sheaths rather than non-laser sheaths, but the laser technique was associated with minor and major sequelae. Roux and colleagues³ found that bilateral laser lead extraction is predictive of problems, which are more likely in patients with older leads or with a previous sternotomy. The likelihood of complications also increases with the number of leads removed and with the inexperience of operators.

The incidence of AVF in this situation is unknown, but it is an uncommon adverse event with a broad clinical presentation. It might involve no symptoms, might cause late onset of mild symptoms, or might even result in sudden severe clinical deterioration that leads to death. Using the key words “arteriovenous fistula,” “pacemaker,” and “defibrillator,” we searched the online PubMed database and found reports of 11 iatrogenic AVFs associated with PPM–ICD leads. Three of these fistulae were caused by lead insertion,^7,8 whereas the other 8 fistulae were caused by removal of the leads via excimer laser sheaths.5,6,8,9 The AVFs were in different locations, most involving the left-sided vessels. We found 4 cases of lead extraction involving 5 AVFs that were successfully stented.⁶ Although these data are insufficient to enable definitive conclusions, they show that stenting across the AVF can be effective and safe, as is further confirmed by our case.

To the best of our knowledge, we have reported the first case in which an AVF between the RIMA and the SVC was associated with PPM–ICD lead extraction by means of a laser sheath. Endovascular stenting is a reasonable alternative to coil embolization or surgical repair of an AVF that results from laser lead extraction. As the average age of the population continues to rise, this complication can be expected to occur with increasing frequency.