AT THE NORTHWESTERN VASCULAR SYMPOSIUM
CHICAGO (FRONTLINE MEDICAL NEWS) – Catheter dependence is often the final option available for hemodialysis patients who have exhausted upper extremity access because of central venous obstruction. But an alternative device that combines a standard expanded polytetrafluoroethylene (ePTFE) arterial graft component with an entirely internalized central venous catheter component may provide an additional option that can help avoid catheters in selected patients, according to pooled results reported at a symposium on vascular surgery sponsored by Northwestern University.
Virginia L. Wong, MD, of University Hospitals Cleveland Medical Center, reported on her group’s and others’ experience using the Hemodialysis Reliable Outflow (HeRO) graft (Merit Medical) to gain access to the superior vena cava (SVC), thus allowing for further upper extremity access options. The device has its limitations in patients with CVO, Dr. Wong noted, “but it can be an important tool for the dedicated access surgeon who is likely to be referred the most complicated patients who have run out of just about every other option.”
The Food and Drug Administration approved the HeRO graft for CVO in 2008, but a recent pooled analysis ( Eur J Vasc Endovasc Surg. 2015;50:108-13 ), which showed a 1-year primary patency rate of 22% and a secondary patency rate of 60%, may provide clarity on how the device can be used to treat CVO in end-stage renal disease (ESRD) patients when the care team desires an alternative to femoral arteriovenous graft, Dr. Wong said. “The 1-year primary patency rate overall was not very good, but with aggressive thrombectomy programs the 1-year patency rate was decent,” she said.
The pooled analysis involved eight series from 2009 to 2015, but the largest series, which involved 164 patients, reported primary and secondary patency rates of 48.8% and 90.8%, respectively ( Eur J Vasc Endovasc Surg. 2012;44:93-9 ). “Patency for these alternative accesses may not be quite what we can achieve with standard upper-extremity access,” Dr. Wong said, “but these patients do not have the standard access as an option.”
Dr. Wong explained where the HeRO fits into the existing vascular practice. “The current data suggest that we should try to exhaust all traditional upper extremity access options before considering anything else, but the HeRO could be considered as an acceptable option for suitable patients,” she said. However, to achieve those outcomes, “you need to have an aggressive thrombectomy program.”
HeRO may be an option for salvage of an existing arm access, plagued by recalcitrant CVO, while still preserving the femoral sites and for future hemodialysis access and/or renal transplantation, Dr. Wong said.
The HeRO also has been used in alternative configurations, taking advantage of axillary or subclavian routes to the SVC when both internal jugular veins are occluded. Dr. Wong has used the femoral route to the inferior vena cava (IVC) for salvaging the femoral AV graft in which iliofemoral venous outflow has been compromised.
Anatomically, the patient must be able to accept a large-bore (19-Fr) access catheter into the central vein. Physiologically, the patient must be able to maintain patency of the long, low-resistance HeRO circuit, which can be up to 50 cm in length, she said. The protocol at Dr. Wong’s institution recommends an inflow arterial diameter of at least 3 mm, along with a left ventricular ejection fraction of 20% or greater and a minimum systolic blood pressure of 100 mm Hg for HeRO on the right side, and possibly higher when coming from the left.
Chronic hypotension is a frequent disqualifier, although some of these patients may benefit from midodrine hydrochloride, she said. In any event, a review of medications and consultation with nephrology and the dialysis unit are mandatory elements of patient screening. “I usually request hemodialysis run sheets from the last three sessions to see what systolic blood pressure excursion is like over the course of treatment,” she said.
The basic principles of hemo-access care are important when considering the HeRO for CVO patients, Dr. Wong said. These include site/side preservation, catheter avoidance and “not to burn any bridges” for future access. “Individualization of care and careful patient selection are probably the best bets if you’re just starting out,” she said. “Choose good patients before resorting to HeRO as the last option for a fairly marginal candidate.”
Dr. Wong had no relevant financial relationships to disclose.