BRIEF REPORT

Assisted Maturation of Native Fistula in Two Patients with a Continuous Flow Left Ventricular Assist Device Talia Sasson, MD, Richard E. Wing, MD, Thomas H. Foster, PhD, Randeep Kashyap, MD, Devang Butani, MD, and David L. Waldman, MD, PhD ABSTRACT Patients who receive a left ventricular assist device (LVAD) are prone to develop end-stage renal disease. Primary arteriovenous fistula (AVF) maturation in these patients may be unsuccessful secondary to the nonpulsatile flow with an LVAD. Two patients with LVADs are described in whom assisted maturation aided long-term AVF patency.

ABBREVIATIONS AKI = acute kidney injury, AVF = arteriovenous fistula, ESRD = end-stage renal disease, LVAD = left ventricular assist device

Deterioration of renal function is common in patients with advanced heart failure after implantation of left ventricular assist device (LVAD) (1–3). Of patients without renal dysfunction before LVAD implantation, 10%–56% develop postoperative acute kidney injury (AKI) (1–3). Overall, about 32% of patients with an LVAD and AKI require renal replacement therapy in the immediate postsurgical period. In a series of nine patients with AKI after LVAD implantation, 22% developed chronic renal failure and needed long-term dialysis (1). The literature is scant regarding the optimal dialysis method in patients with LVAD and end-stage renal disease (ESRD) possibly because there are relatively few patients in any single center. An in-depth review by Patel et al (4) stated there are no studies of arteriovenous fistula (AVF) maturation in patients with an LVAD. Patel et al (4) believed that AVFs would not mature in patients with an LVAD secondary to nonpulsatile flow, and they recommended arteriovenous grafts instead. We present two cases of patients with

From the Department of Imaging Sciences (T.S., T.H.F., D.B., D.L.W.), Department of Medicine, Division of Nephrology (R.E.W.), and Department of Surgery (R.K.), University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642. Received August 30, 2013; final revision received January 1, 2014; accepted January 13, 2014. Address correspondence to: T.S.; E-mail: [email protected] None of the authors have identified a conflict of interest. & SIR, 2014 J Vasc Interv Radiol 2014; 25:781–783 http://dx.doi.org/10.1016/j.jvir.2014.01.013

ESRD after LVAD implantation in which AVFs were placed for hemodialysis access. In both cases, long-term patency was achieved by assisted maturation.

CASE REPORTS Case 1 A 49-year-old man had a HeartMate II (Thoratec Corporation, Pleasanton, California) LVAD placed owing to left heart failure. After surgery, the patient developed AKI requiring hemodialysis. A right radiocephalic AVF was placed 1 year later. At 77 days after surgery, the fistula was immature, and the patient was referred for an assisted maturation procedure. A fistulogram (Fig 1a) showed 50% stenosis at the anastomosis and a forearm cephalic vein with maximum diameter of 6.1 mm and multiple collateral veins. The cephalic vein in the arm and the central veins were normal. Balloon dilation of the cephalic vein from the level of the elbow to just distal to the arteriovenous anastomosis was performed with an 8-mm balloon (Conquest; C.R. Bard, Covington, Georgia), followed by an 80-mm-long, 10-mm-diameter balloon (Diamond; Boston Scientific, Natick, Massachusetts). The anastomosis was treated 14 days later with a 6-mm balloon (Sterling; Boston Scientific). A fistulogram obtained 30 days later (Fig 1b) showed a maximum cephalic vein diameter of 12.6 mm. The fistula was considered mature and was approved for use. The patient returned 224 days later because of decreased AVF flow. A fistulogram showed an anastomotic stenosis, which was treated with

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Assisted Maturation of AVF in Patients with LVAD

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Figure 1. Case 1. (a) Initial fistulogram shows stenosis of the radiocephalic anastomosis (arrow). Diameter of the cephalic vein is 6.1 mm (asterisk) with collaterals arising from the cephalic vein (arrowhead). (b) Final fistulogram shows cephalic vein 12.6 mm in diameter (asterisk). Most collaterals disappeared, and there is slower flow in the existing collateral (arrowhead). Inflow is normal. The stenosis of the arteriovenous anastomosis disappeared (arrow).

Figure 2. Case 2. (a) Initial fistulogram shows stenosis of the radiocephalic anastomosis (arrow). The cephalic vein diameter is 4.1 mm, and the vein is irregular (asterisk). There are large collaterals near the anastomosis (arrowhead). (b) Fistulogram obtained after maturation shows normal arteriovenous anastomosis (arrow). The cephalic vein is mature with a diameter of 21.6 mm (asterisk). There is still flow in the collateral near the anastomosis (arrowhead).

a 4-mm balloon (Sterling). The patient continued dialysis via the fistula without issue until his death 243 days later because of sepsis from an infected LVAD lead.

Case 2 A 46-year-old man had a HeartMate II LVAD placed. His kidney dysfunction progressed over 34 months to ESRD requiring hemodialysis. He underwent left radiocephalic AVF placement. At 91 days after surgery, the fistula had failed to mature, and he was referred for assisted maturation. A fistulogram (Fig 2a) showed a 4 50% stenosis of the arteriovenous anastomosis with an adjacent 2-cm-long venous stenosis. Distal to the stenosis, the cephalic vein diameter was 4.1 mm, with multiple collaterals. Arm veins and central veins were normal. The anastomosis and the stenotic vein were dilated with a 6-mm balloon (Sterling). The perianastomotic cephalic vein had matured 28 days later and was 21.6 mm in diameter; however, the cephalic vein outflow was occluded from the level of the midforearm with the fistula draining through collaterals. The occlusion was crossed, and the cephalic vein was dilated to the level of the elbow with an 8-mm balloon (Conquest). A fistulogram (Fig 2b) obtained 1 month later showed a mature AVF, ready for dialysis access. The patient presented with decreased fistula flow 294 days after maturation. A fistulogram showed a venous anastomotic stenosis,

which was treated with a 6-mm balloon (Diamond). At the present time, the patient’s LVAD is still operative, and he remains on dialysis via his AVF 511 days from the date of assisted maturation.

DISCUSSION An increasing number of patients are living with LVADs and require long-term dialysis. Catheter hemodialysis is undesirable in general because of the high associated morbidity and mortality from infection (5). Patients with LVADs are already susceptible to infection introduced via the lead electrode in the skin (4). AVFs provide optimal hemodialysis access in the general population with prolonged survival, fewer infections, lower hospitalization rates, and reduced costs (5). However, prior literature suggests that AVFs in patients with LVADs do not work for two reasons. The first is that the AVF is unlikely to mature because of lack of vascular reactivity as a result of nonpulsatile flow (4). This conclusion is based on a clinical study that demonstrated nonpulsatile flow was associated with decreased flow-mediated vasodilation (6). In our institution, spontaneous maturation of an AVF has not occurred in any patient. However, if an AVF does not mature on its own, assisted maturation permits successful hemodialysis access in many patients in the general population. A second concern regarding AVFs

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after LVAD placement is that the patient’s blood pressure is maintained in the range of 80–100 mm Hg. Chang et al (7) showed that hypotension during dialysis may cause access thrombosis even in the absence of an anatomic lesion. Although one of our two patients did have a thrombosis, it was successfully treated, and access was preserved for another 211 days. With such a small sample, there is no way to assess whether the thrombosis rate in patients with an LVAD is greater than that of the general population with AVFs. We do not know if the immature AVFs in our patients were the result of continuous flow because 28%–52% of AVFs in patients without LVADs never mature, especially if the AVF is in the forearm (8). Our two patients both had inflow lesions, small cephalic veins, and multiple collaterals. In both patients, the inflow lesions were corrected, and the cephalic veins were dilated. In our practice, we do not routinely performed embolization of collateral veins because we have found in some instances that the collaterals protect the fistula by providing alternative outflow. This alternative outflow may be especially important in a patient with an LVAD who has low blood pressure and is prone to thrombosis. In our second patient, despite an occlusion of the cephalic vein at the midforearm level, the more proximal fistula remained patent because of outflow through the collateral veins. In addition, after recanalization, the fistula has remained open and functional despite the collaterals. Our primary patency (calculated from the time the fistula was approved for use to the first intervention) was 224 days in the first patient and 329 days in the second patient. Cumulative patency was 329 days in the first patient and 511 days in the second patient. These primary and cumulative patencies are similar to the patencies expected in patients without an LVAD in

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whom the primary patency rate is 60% at 1 year and 50% at 2 years with a cumulative patency after intervention of 71% at 1 year and 64% at 2 years (9). In conclusion, the current literature suggests that AVFs are ineffective in patients with an LVAD because of lack of maturation or risk of thrombosis or both. We describe two patients with LVADs who underwent placement of radiocephalic AVFs. Assisted maturation was required in both patients, but when this was accomplished, the fistulas worked with cumulative patency similar to that in patients without an LVAD. On the basis of our limited experience, we suggest that AVFs may be useful in patients with LVADs and ESRD.

REFERENCES 1. Borgi J, Tsiouris A, Hodari A, Cogan CM, Paone G, Morgan JA. Significance of postoperative acute renal failure after continuous-flow left ventricular assist device implantation. Ann Thorac Surg 2013; 95:163–169. 2. Demirozu ZT, Etheridge WB, Radovancevic R, Frazier OH. Results of HeartMate II left ventricular assist device implantation on renal function in patients requiring post-implant renal replacement therapy. J Heart Lung Transplant 2011; 30:182–187. 3. Sandner SE, Zimpfer D, Zrunek P, et al. Renal function and outcome after continuous flow left ventricular assist device implantation. Ann Thorac Surg 2009; 87:1072–1078. 4. Patel AM, Adeseun GA, Ahmed I, Mitter N, Rame JE, Rudnick MR. Renal failure in patients with left ventricular assist devices. Clin J Am Soc Nephrol 2013; 8:484–496. 5. Vassalotti JA, Jennings WC, Beathard GA, et al. Fistula first breakthrough initiative: targeting catheter last in fistula first. Semin Dial 2012; 25:303–310. 6. Amir O, Radovancevic B, Delgado RM 3rd, et al. Peripheral vascular reactivity in patients with pulsatile vs axial flow left ventricular assist device support. J Heart Lung Transplant 2006; 25:391–394. 7. Chang TI, Paik J, Greene T, et al. Intradialytic hypotension and vascular access thrombosis. J Am Soc Nephrol 2011; 22:1526–1533. 8. Robbin ML, Chamberlain NE, Lockhart ME, et al. Hemodialysis arteriovenous fistula maturity: US evaluation. Radiology 2002; 225:59–64. 9. Al-Jaishi AA, Oliver MJ, Thomas SM, et al. Patency rates of the arteriovenous fistula for hemodialysis: a systematic review and meta-analysis. Am J Kidney Dis In press; available online October 30, 2013.

Assisted maturation of native fistula in two patients with a continuous flow left ventricular assist device.

Patients who receive a left ventricular assist device (LVAD) are prone to develop end-stage renal disease. Primary arteriovenous fistula (AVF) maturat...
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