Mega-fistula

Salvage Aneurysmorrhaphy as an Adaptable and Still Pertinent Technique in the Management of Challenging True Aneurysms of Arteriovenous Fistulas: A Case Series of Different Variations, With Illustrative Surgical Pictures

Introduction

Aneurysmorrhaphy, described as reduction aneurysmoplasty, partial aneurysmectomy, or vessel wall recalibration, can be considered a suitable surgical plan for true aneurysms of arteriovenous fistulas (AVFs), allowing for a dynamic approach to reconstruction of aneurysmal AVFs of different severities, ensuring salvage of the native access.

Report

Six challenging cases of AVF aneurysms are presented, some with extremely dilated and tortuous megafistulas, for which three surgical technique variations were performed. The patients had a mean age of 59.2 years, 50% were female, with brachiocephalic (n = 5, 83.3%) or brachiobasilic (n = 1, 16.7%) AVFs. The fistulas were created an average of 4.67 years previously, and the aneurysms had an average maximum diameter of 37.5 mm (range 25-60 mm). Surgical indications were rupture risk, thrombosis, or outflow stenosis compromising haemodialysis, infections, and concerns for quality of life (affected by post-puncture bleedings, disfiguring aesthetics, pain, and discomfort). The surgical techniques were simple aneurysmorrhaphy (n = 3, 50%), aneurysmorrhaphy with partial excision of aneurysmal segment with end to end anastomosis of venous ends (n = 2, 33.3%), and aneurysmorrhaphy with establishment of new venous outflow (n = 1, 16.7%). All AVFs were patent post-operatively and at follow up (mean 5.6 months, median one month). Haemodialysis was resumed through the AVFs at a mean of 2.17 weeks post-operatively, with placement of an alternative route for haemodialysis in the meantime. No patients experienced post-operative complications.

Discussion

Experience with the more challenging cases shows that aneurysmorrhaphy can still be considered an acceptable, flexible, and pertinent method for salvage of megafistulas, giving the surgeon the much needed versatility to adapt to anatomical and pathological variations, with high patency rates and minimal complications, especially when other treatment options are not possible in complicated cases. AVF salvage through aneurysmorrhaphy allows for a dynamic approach to the reconstruction of severely tortuous, dilated veins, ensuring patency of the native AVF.

Salvage of a megafistula causing high-output cardiac failure in a young adult with aneurysmorrhaphy and banding

We present the case of a 21-year-old male with significant lengthening and aneurysmal degeneration of his brachiocephalic arteriovenous fistula resulting in a megafistula and high-output cardiac failure. A computed tomography angiogram showed narrowing at the cephalic arch. Further evaluation during the operation revealed kinking and elongation of the fistula in addition to compression of the cephalic arch in the deltopectoral groove leading to outflow obstruction. The aneurysmal fistula was treated successfully with aneurysmorrhaphy of the remaining conduit and banding of the inflow. This case demonstrates a unique etiology of venous outflow obstruction for a fistula and describes the surgical approach to its treatment in a young patient suffering from cardiac failure.

Mega Fistulae! A case series

A mega fistula can be defined as generalized aneurysmal dilatation of arteriovenous fistula. Mega fistulae can lead to complications like high output cardiac failure, steal syndrome, skin ulceration and rupture. We describe a series of ten patients who were referred to our interventional nephrology practice for evaluation of mega fistula which had not been in use for a long time. Nine out of ten patients were post-transplant while one was pre dialysis. Five patients had Radiocephalic while four had Brachiocephalic and one had Brachial artery to Median Cubital vein fistula. All except one patient had severe outflow stenosis. The most common site of stenosis in Radiocepahlic and Brachiocepahlic fistula was cephalic vein at the elbow and cephalic arch respectively. Half of the patients had chronic total occlusion of the outflow vein. Successful angioplasty was done in only two patients. Seven patients underwent ligation while one had spontaneous thrombosis of the fistula. None of the patients had regular surveillance of their access for a long time as they were not on dialysis. Unrecognized and uncorrected outflow stenosis over a long time period can lead to creation of mega fistula. Once a mega fistula develops there are not many treatment options other than ligation. This leads to loss of the access which might be needed in future. Continuous access surveillance in patients who are not on dialysis is important to prevent complications like mega fistula.

A technique for the salvage of megafistulas allowing immediate dialysis access

OBJECTIVE

Almost two million individuals are undergoing renal replacement therapy worldwide, with hemodialysis being the common form. Many factors influence the primary patency of an arteriovenous fistula (AVF), including vessel size, fistula flow rates, cannulation practice, and thrombotic tendencies. Excess dilation of the AVF, resulting in the development of a megafistula, is a complication that can result in a need for AVF revision and subsequent failure.

METHODS

The charts of patients who underwent autogenous AVF revision because of the development of a megafistula with aneurysmectomy and vein transposition by a single surgeon during a 7-year period from 2009 through 2016 were reviewed. A technique is described in which after aneurysmorrhaphy, the repaired venous component of the AVF is transposed through a new tunnel while the vein is rotated 90 degrees. This allows the AVF to be accessed immediately, making placement of a tunneled dialysis catheter unnecessary.

RESULTS

There were 102 patients included in the study, with follow-up ranging from 7 to 95 months. In our cohort, 92 of the 102 revised AVFs (90.2%) maintained primary functional patency. Of the 102 patients who underwent this revision technique, there were 10 fistulas that subsequently failed after a mean of 29 months. There were only seven patients who experienced recurrent fistula dilation requiring repeated aneurysmectomy.

CONCLUSIONS

We describe a technique for management of the development of a megafistula that uses only autogenous tissue and, perhaps most important, eliminates the need for temporary dialysis catheter placement.