Brachiocephalic Artery to Left Brachiocephalic Vein Fistula Complicating Lead

History

A 49-year-old female followed for management of a dual-chamber pacemaker for complete AV block was seen in clinic with complaints of exertional intolerance. Prior clinic evaluations of her pacemaker system had demonstrated intermittent atrial lead noise. Decreasing atrial sensitivity ameliorated inappropriate inhibition due to noise, but resulted in undersensing of atrial activity at higher heart rates. This resulted in symptomatic loss of AV synchrony, given the patient’s very physically active lifestyle.

The patient had a complex prior arrhythmia and device history. She had undergone placement of transvenous abdominal VVI-ICD in 1998 at age 31 for near-syncope and prolonged QT interval, though she had not had documented polymorphic ventricular arrhythmias and was non-inducible at EP testing. 

Three years later, following multiple inappropriate shocks for SVT, she underwent ablation of typical AVNRT resulting in first-degree AV block, but she remained inducible. At this point, her abdominal ICD generator and transvenous lead were removed, and a pectoral dual-chamber ICD was implanted to permit better tachycardia discrimination. Nonetheless, she continued to have symptomatic breakthrough SVT and inappropriate shocks; therefore, she underwent repeat ablation in 2002, which was complicated by complete AV block. 

She underwent ICD generator replacement 5 years later, but in 2013 when replacement was again needed, the decision was made to replace her ICD with a dual-chamber pacemaker in light of the fact that her QT interval had normalized and she had never received appropriate ICD therapies for VT. 

Management options reviewed with the patient included: placement of a new atrial lead only, new atrial and ventricular leads (given the age of the RV lead and expected lead longevity), placement of an entirely new system on the contralateral side, or extraction and replacement of the entire indwelling system. Based on her very active lifestyle, age, the age of her leads (which were now 15 years old), and her desire for an MRI conditional system, the decision was made to attempt extraction of both leads with ipsilateral replacement with a dual-chamber pacemaker. 

Procedure

A coronal section for preoperative CT is shown in Figure 1. Possible areas of calcification can be seen adjacent to the lead in the region of the proximal brachiocephalic vein. The ventricular lead is a Guidant 0147, and the atrial lead is a Guidant 4480 Fineline.

Per institutional protocol, the extraction was done under general anesthesia in the OR with CV surgical backup. A temporary pacing lead was placed from the left femoral vein, and an 0.035-inch Amplatz Super Stiff Guidewire (Boston Scientific) was advanced from the right femoral vein for rapid deployment of an occlusion balloon if required. 

Both leads were prepared in standard fashion with locking stylets (LLD, Spectranetics/Philips). Initial attempts at extraction of the leads with 12 Fr and 14 Fr excimer laser sheaths (GlideLight, Spectranetics/Philips) and conventional Teflon sheaths were unsuccessful due to dense and presumably calcified scar tissue encountered at the level of the brachiocephalic vein. Ultimately, both 11 Fr and 13 Fr rotating mechanical sheaths (TightRail, Spectranetics/Philips) were required to navigate past the adhesions, which extended from the brachiocephalic vein to approximately the SVC/RA junction. With the exception of the distal electrode pair of the right atrial lead, which fractured during the extraction process, the remaining hardware was removed successfully. Venous access was maintained through the extraction sheath, and the amount of bleedback from the extraction sheath was as expected. A new dual-chamber pacemaker was placed without incident. Physical exam the following day was unremarkable, and the patient was discharged from the hospital.

Subsequent Clinical Course

Seven days post operatively, the patient experienced an episode of deep retrosternal pain while walking up a hill. The pain resolved, but the following evening, the patient noted some mild exertional dyspnea and an audible “whirring” sound from her upper chest. She presented to the emergency department for further workup. She remained hemodynamically stable and without recurrent chest pain. On physical exam, a loud holosystolic murmur and thrill were appreciated in the suprasternal notch. A CTA of the neck was done in the ED. No clear evidence of AV communication was noted, but images were felt to be compromised in part due to beam hardening. However, clinical findings were strongly suggestive of an arteriovenous fistula, and based on the location of the murmur and area of densest scar encountered during the extraction, the region of greatest concern was the aorta and arteries of the head and neck, rather than a more peripheral subclavian artery-subclavian vein fistula. 

The patient was referred for arch aortography. Selected images are shown in Figures 2A and 2B. Early filling was noted into the left brachiocephalic vein and SVC consistent with AV fistula. Based on the filling pattern and location of passage of the catheter between the aortic arch and left brachiocephalic vein, the fistula was felt to be reasonably large and resulting in a communication between the brachiocephalic vein and either proximal brachiocephalic artery or potentially the aortic arch itself. 

To further clarify the functional significance of the shunt, RHC was performed with the following results:

• SVC Sat 81%
• IVC Sat 64%
• Right atrial pressure: 15/13/12, Saturation 83%
• Right ventricular pressure: 30/7/13
• Pulmonary arterial pressure: 27/12/21, Saturation 76%
• Pulmonary wedge pressure: 14/20/13
• Qp 6.6 L/min, Qs 4.4 L/min, shunt flow 2.2 L/min, Qp/Qs 1.5

Echocardiogram demonstrated normal RV and LV size and function. Mild-moderate TR was noted.

To gather additional data for the purpose of determining therapeutic options, the images from the neck CTA were reformatted. A representative image is shown in Figure 3, and demonstrates a 6 mm x 8 mm AV fistula between the posterior wall of the brachiocephalic vein and the anterior wall of the brachiocephalic artery, with the proximal end of the fistula 9.5 mm from the aortic origin. 

Consultations were obtained from Interventional Radiology, Vascular Surgery, and Cardiac Surgery, and included watchful waiting, covered stent placement within the innominate, subclavian-subclavian bypass with ligation of the innominate, and open repair via median sternotomy. 

After a review of options was presented, the patient elected to undergo direct repair, which was performed about 6 weeks later. Figure 4 is an intraoperative photograph showing the hole in the brachiocephalic vein repaired at surgery. The pacing lead cannot be seen in the image, but was undamaged. 

Postoperative recovery was uneventful, and the patient returned to full activity and remains active at 1-year follow-up. 

Discussion

There remains significant variance in opinion regarding indication and risk/benefit tradeoffs for extraction of non-infected leads.^1,2 Through multiple studies, major procedural complication rates range from 1.8-2.5% with mortality rates of 0.3-0.9%, with greater success and lower complication rates at higher volume centers.³ What is clear is that the decision to extract is not to be taken lightly. 

Arteriovenous fistulae are a recognized complication of lead extraction with published reports of LIMA-brachiocephalic, left common carotid-brachiocephalic, carotid-subclavian, and, as with our case, brachiocephalic artery-left brachiocephalic vein (BCA-LBCV), with incidence in one large series of 0.4%.⁷ Management of these fistulas is also controversial, with the most common approach being endovascular stenting despite the absence of long-term data on efficacy. To our knowledge, this is only the second reported case of BCA-LBCV fistula managed with open surgical repair.⁴

While proposed, a conservative strategy of “watchful waiting” was not felt to be optimal for several reasons. The size of the fistula would make spontaneous closure highly unlikely and the potential risk of fistula enlargement or subsequent vascular catastrophe unknown. Long-term data are not available on the outcome of acquired AV shunts in this circumstance. Randomized data on secundum ASD patients have suggested that closure is indicated for Qp/Qs>1.7, which this patient does not meet, but aside from the unsettling noise from the shunt, her symptoms of dyspnea suggested that this patient’s exercise capacity would be negatively impacted by the additional pulmonary flow even if RV function remained preserved.⁵ Coiling of the fistula was not an option due to the size of the communication and absence of a defined neck. Endovascular stenting has been reported for treatment of post-ablation fistulas.^6,7 The arteriograms in this case were inconclusive as to the precise location of the fistula with respect to the origin of the brachiocephalic artery, but the reformatted CTA images did demonstrate what was felt to be an adequate “landing zone”. Coated stenting of the subclavian artery has an acute success rate of 93%, but a 5-year patency rate of only 70%,⁸ with 12% presenting with stent thrombosis at 4-year mean follow-up.⁹ In the series reported by Cronin, all fistulas were managed with endovascular stenting. The 3 BCA-LBCV fistulas in their series all presented acutely at time of extraction, and long-term patency data are not available. Given the need for intermittent surveillance with imaging, and the potential for stent thrombosis with potentially catastrophic consequences based on location, the patient did not feel this was a viable option. Had this patient been elderly, or felt to be at unacceptable risk for open repair, this would have likely been a more viable management approach. While there are no long-term data on subclavian-subclavian bypass, the data on subclavian-carotid bypass show patency rates of 96% at 5 years, but given this patient’s very active lifestyle and the anatomic course of a subclavian-subclavian graft, patency rate would likely be lower, with potentially dramatic consequences of graft closure. 

This case was unusual in its delayed presentation, which fortunately did not result in significant hemodynamic compromise. Treatment options for iatrogenic AV fistulas following extraction must be individualized based on the specific anatomy as well as patient characteristics and preferences.

Acknowledgement

The author wishes to acknowledge the contributions of Sara May, MD, Robert Osnis, MD, Daniel Susanto, MD, and Mark Hill, MD, in the preparation of this case report.

Disclosure: The author has no conflicts of interest to report regarding the content herein.  

References

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