Commentary

Commentary: Should AVFs be ligated after kidney transplant?


 

Hemodynamic complications of arteriovenous (AV) access are uncommon but can be potentially life threatening. Fistulas and grafts can cause a decrease in systemic vascular resistance and secondary increase in cardiac output in patients who may already have myocardial dysfunction secondary to their end-stage renal disease.1 This increased cardiac output is usually insignificant but in rare cases can result in clinically significant cardiac failure. Patients with high-output fistulas with volume flow greater than 2 L/min may be at increased risk of heart failure but volume flow less than 2 L/min does not preclude this complication.2

Dr. Larry A. Scher

Dr. Larry A. Scher

In patients with AV access–related heart failure, optimal medical management and reduction of fistula flow or ligation of the dialysis access should be considered. If continued hemodialysis is necessary, loss of a functioning dialysis access is problematic and difficult management decisions must be made. Following successful renal transplantation, ligation of vascular access in the presence of symptomatic heart failure may represent a straightforward decision. Nonetheless, there is no clear consensus of how to manage patent fistulas or grafts in patients following renal transplantation in the absence of significant cardiac symptoms with particular concern to the important issues of transplant survival and long-term cardiac prognosis. Yaffe and Greenstein3 recommend preservation of almost all fistulas after transplantation in the absence of significant complications such as venous hypertension, pseudoaneurysm, significant high-output cardiac failure or hand ischemia. They recommend taking into account the 10-year adjusted renal transplantation graft survival rates and the relative paucity of donors, recognizing the possibility that the patient may have to return to dialysis at some point in the future. They also reference the lack of information regarding the beneficial impact of fistula ligation on cardiac morphology and function as a rationale for access preservation.

A recent presentation at the American Heart Association Scientific Sessions by Michael B. Stokes, MD,4 from the department of cardiology at Royal Adelaide Hospital in Australia, suggests that cardiovascular disease is responsible for 40% of deaths among kidney transplant recipients and that left ventricular (LV) mass is strongly associated with cardiovascular mortality.

He states that, although there is no guideline consensus on the management of an AV fistula following successful renal transplantation, the fistula continues to contribute adversely to cardiac remodeling and function. The lack of previous randomized controlled trials in this area led Dr. Stokes and his colleagues to randomly assign 64 patients at least 1 year following successful kidney transplantation with stable renal function and a functioning AV fistula to either fistula ligation or no intervention. All patients underwent cardiac MRI at baseline and 6 months.

The primary endpoint of decrease in LV mass at 6 months was significant in the ligation group but not in the control group. The ligation group also had significant decrease in LV end diastolic volume, LV end systolic volume, and multiple other parameters. In addition, NT-proBNP levels and left atrial volume were significantly reduced in the ligation group when compared with the control group. Complications in the ligation group included six patients with thrombosis of their fistula vein and two infections, all of which resolved with outpatient anti-inflammatory or antimicrobial therapy.

Dr. Stokes believes that control patients in his study face “persisting and substantial deleterious cardiac remodeling” and that “further investigation would clarify the impact of AV fistula ligation on clinical outcomes following kidney transplantation.”

I believe this is important information and represents the first randomized controlled data regarding the long-term adverse cardiac effects of a patent fistula after renal transplantation. Unfortunately, information regarding baseline fistula volume flow is not provided in this abstract. As discussed earlier, patients with high-flow fistulas may be at increased risk of heart failure and hemodynamic data can be critical in establishing an algorithm for managing these challenging patients.

Ligation of a functioning and asymptomatic access in a patient with a successful renal transplant should be recommended only after informed discussion with the patient weighing the ongoing potential negative effects on cardiac function of continued access patency versus the potential need for future hemodialysis. Dr. Stokes presents interesting data that must be considered in this controversy. I believe that, in the absence of a universally applicable algorithm, the clinical decision to recommend AV fistula ligation after successful kidney transplantation should be individualized and based on ongoing assessment of cardiac and renal function and fistula complications and hemodynamics.

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